During the operation of an electric machine, some electrical components of the machine may increase in temperature. In some electric machines, it may be undesirable for some electrical components of the machine to increase in temperature during operation and, at the same time, it may be desirable for some other electrical components of the machine to increase in temperature during operation. In conventional electric machine thermal management systems, coolant fluid is commonly utilized to provide cooling to components of an electric machine, or to the electric machine in its entirety. In such systems, directed cooling to particular components of the electric machine may be difficult because of the dynamic operation of some electric machines.
For example, in some electric machines, such as electric motors or generators, the machine includes a stationary component, often referred to as a stator, and a rotational component, often referred to as a rotor. In electric motors, electric current is translated into electromagnetic fields that exert a mechanical force, or torque, between the stator and the rotor, which may be used to do work. Generators work on similar principles as electric motors but with mechanical force being translated into electric current. While primarily described in terms of rotational force, or torque, the principles described herein are also applicable to linear motors. For example, in some linear motors, the rotor serves as the stationary component while the stator serves as a translated component.
Particularly in electrical motors, windings of electrical wire or conductive elements disposed on and/or in the stator and/or rotor of the motor increase in temperature during continued operation of the machine. Thermal management of these windings or conductive elements is particularly important in electric motors because as the temperature of the windings or conductive elements increases, the output performance of the electric motor decreases. As such, liquid coolant is often flowed through the motor during operation to provide cooling to the windings or conductive elements disposed on and/or within the stator and/or rotor of the machine. Unfortunately, these conventional thermal management systems and methods of electric machines may generate inefficiencies and additional losses of performance to other components of the electric machine. Therefore, an improved thermal management system and method of electric machines are necessary for the improvement of the performance of electric machines and motor assemblies.
The present disclosure provides systems and methods of thermal management of electric machines using coolant cans.
In some aspects of the disclosure, an electric machine having a thermal management system includes a stator having a stator core and a rotor having a rotor core that is movable with respect to the stator. One or more windings are included in at least one of the stator or the rotor of the electric machine. One or more coolant cans encapsulate the one or more windings of the at least one of the stator or the rotor in an interior compartment of the coolant can that defines a coolant flow passage through the one or more windings. The coolant can includes a coolant inlet and a coolant outlet in fluid connection with the interior compartment of the coolant can that is fluidically isolated from the stator core and the rotor core.
In another aspect of the disclosure, an electric machine having a thermal management system includes a stator having a stator core, a rotor having a rotor core that is movable with respect to the stator, a coolant pump, and a controller in electrical connection with the coolant pump that is configured to control the coolant pump. One or more windings are included in at least one of the stator or the rotor of the electric machine. One or more coolant cans encapsulate one or more of the windings disposed on or within the at least one of the stator or the rotor in an interior compartment of the coolant can that defines a coolant flow passage through the one or more windings. The coolant can includes a coolant inlet and a coolant outlet in fluid connection with the interior compartment, and the coolant pump is in fluid communication with one or more coolant inlets of the one or more coolant cans.
In still another aspect of the disclosure, a method for thermal management of an electric machine having a thermal management system includes flowing a coolant through an interior compartment of one or more coolant cans that encapsulate one or more windings of the electric machine within the interior compartment of the coolant can. The interior compartment of the coolant can being fluidically isolated from other components of the electric machine.
The foregoing and other aspects and advantages of the disclosure will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred configuration of the disclosure. Such configuration does not necessarily represent the full scope of the disclosure, however, and reference is made therefore to the claims and herein for interpreting the scope of the disclosure.
As detailed above, some electric machines may require a thermal management system, including cooling and thermal management systems, during operation in order to maintain performance and increase the lifecycle of the machine. This disclosure relates to a thermal management system of an electric machine, for example, an electric motor with an electromagnetically coupled rotor and stator. In an electric motor, either or both of the stator and the rotor include windings of electrical wire or conductive elements that allow for electromagnetic coupling by currents travelling through the windings. These currents cause heat to dissipate in the windings, with potentially negative effects to the performance and lifespan of the electric motor. For example, the conductors or associated components of the electric motor may be mechanically damaged by high temperatures, or the electrical resistance of the conductors may be increased as the temperature of the windings increases resulting in decreased performance of the electric motors.
Liquid coolant can be used to maintain acceptably low temperatures in windings of electric machines, such as windings of an electric motor. Conventional cooling in electric motors includes, for example, forced air cooling, spray cooling and immersion cooling. Forced air cooling pushes air through the motor assembly to cool windings or conductive elements of the motor. Spray cooling systems can be configured to target specific motor components with jets of coolant. Immersion cooling systems immerse the entire motor assembly in a contained volume of liquid coolant in operation. Of these conventional cooling systems, immersion cooling is the most effective at cooling the windings, however, both of the cooling systems described above result in significant amounts of coolant in the working volume of an electric motor, thus causing either or both of at least two undesirable effects.
First, windage or drag losses are increased when moving components of the motor come in contact with coolant, especially when coolant is present in the air gap (i.e., the gap between the stator and the rotor) of the motor, a common result of immersive cooling. Spray cooling may reduce this negative effect but with decreased cooling effectiveness compared to immersive cooling. Additionally, spray cooling typically involves significant interaction between other motor components due to both proximity of the stator and the rotor bodies within the working volume of the motor assembly and effects arising from operation. Forced air cooling also suffers from windage or drag losses, especially at higher air flows that are required for advanced cooling capability or power dense machine designs.
Second, as described above, in conventional electric motor designs, it is beneficial to maintain windings at a lower temperature than their corresponding stator core or rotor core. Immersive cooling, including significant coolant in the working volume of the motor, applies cooling indiscriminately to the windings, the stator core, and the rotor core, such that, as the windings are cooled, the stator core and rotor core are cooled as well. Likewise, spray cooling can result in unintentional cooling of the stator core and the rotor core as the sprayed coolant flows from the windings and disperses in the working volume of the motor, including on the stator core and the rotor core.
In addition, whereas many conductive elements, such as copper in a non-limiting example, are most efficient when regulated at the lowest possible temperature as the resistivity of the winding conductors is proportional to the operating temperature, other materials used in a motor, such as steel laminations in a non-limiting example, may benefit from higher operating temperatures wherein their losses can be minimized under such conditions, for instance. Thus, the direct cooling of some bodies in an electric machine is not always beneficial or desirable, presenting conflicting requirements within a given machine. Other components such as magnets, semiconductors, or even simply the stator or the rotor may demand different thermal capabilities and operating conditions relative to each other, further compounding the thermal management needs of an electric machine.
Furthermore, many traditional electric motor and motor assembly designs utilize passive or active heat jackets that function to remove heat from the conductive elements through the machine core, magnetic elements, or housings of the machine. That is, the thermal flow of the electric machine and the machine assembly is designed to operate through the magnetic components that produce a thermal gradient in which the conductors are a higher temperature than the core. This, in some instances, is detrimental to the performance of the core and/or machine itself as described above.
Recognizing these drawbacks, and in an effort to increase performance of electric machines having windings or conductive elements, the present disclosure provides systems and methods of a thermal management system that provide cooling to windings or conductive elements in isolation from the working volume, including other internal components, of the electric machine. For example, the electric machines described in the present disclosure include coolant cans that encapsulate windings or conductive elements, such that coolant flows through the coolant cans and contacts only the windings or conductive elements of a stator, a rotor, or both. In operation, the coolant cans effectively provide the efficiency benefits of immersive cooling but only to the windings or conductive elements. The coolant cans fluidically isolate the coolant from other internal components of the electric machine, for example, the stator core or the rotor core of an electric motor on which the windings or conductive elements are mounted or electrically in communication with, such that a relatively high temperature can be maintained in the stator core or the rotor core in relation to the encapsulated windings or conductive elements. In some cases, the present disclosure enables the stator core and/or the rotor core to be maintained at a higher temperature than the windings or conductive elements disposed therein during motor operation, representing a significant break with conventional internal motor processes.
As described above, in an electric motor, fluidic isolation of coolant in the windings or conductive elements to the stator core or rotor core can result in improved motor performance. Unlike motor windings, which typically decrease in efficiency as their temperature rises (e.g., because of increasing resistance), stator cores and rotor cores often exhibit increased efficiency with increasing temperature, because induced eddy currents in the stator cores and rotor cores are correspondingly decreased with increasing temperature. Induced eddy currents act to heat the stator cores and rotor cores independently of any heat transferred from the windings. The inclusion of coolant cans in the thermal management systems of the present disclosure allows a relatively high temperature to be maintained in the stator core or rotor core, thereby simultaneously increasing winding efficiency and housing/core efficiency. As used herein, the “performance” of an electric machine refers to the power density, the thermal headroom, and/or the efficiency of the electric machine.
As will be described herein, the present disclosure provides systems and methods for a thermal management system of an electric machine using coolant cans that are configured to provide directed cooling to windings or conductive elements of an electric machine. In one non-limiting example, an electric motor includes coolant cans that encapsulate windings or conductive elements disposed on or within the stator of the motor. Additionally or alternatively, an electric motor or electric motor assembly includes coolant cans that encapsulate windings or conductive elements disposed on or within the rotor of the motor. Additionally or alternatively, an electric motor or electric motor assembly includes coolant cans that encapsulate windings or conductive elements disposed on or within both the stator and the rotor of the motor. Additionally or alternatively, an electric motor or electric motor assembly includes coolant cans that encapsulate windings or conductive elements that are in electrical communication with either the stator or the rotor, or both. Additionally, systems and methods are provided for monitoring and/or regulating coolant flow within, and temperature of, an electric motor or electric motor assembly having a thermal management system using coolant cans.
Although the discussion below frames the present disclosure to electric machines including a stator and/or a rotor, the disclosure is not intended to be limited to such electric machines. In some implementations, the thermal management systems and methods, including the coolant cans, may be applied to other electric machines having windings or conductive elements, for example, an electrical transformer and an electrical inverter. In various implementations, the thermal management systems and methods may be applied to generators, coupled electric (or electromagnetic) systems, and mechanical and/or electrical power conversion devices that alter the mechanical or electric pressure and flow of energy from one input to a desired output.
In some implementations, the thermal management systems and methods, including the coolant cans, described below may be applied to provide coolant or thermal regulation to electrical components or environments other than windings or conductive elements of an electrical machines. For example, in some implementations, a transformer of an electrical machine can be encapsulated within one or more coolant cans according to the present disclosure. In some implementations, an inverter of an electrical machine or system can be encapsulated within one or more coolant cans according to the present disclosure.
For the purposes of this disclosure, windings and conductors/conductive elements may be used interchangeably throughout. Conductive elements may include bars, printed circuit boards (PCBs), semiconductors, litz wire, multi-turn coils, cast or solid conductors, carbon nanotubes, or any other element that can conduct electricity in an electrical circuit.
The electric motor 102 has an output shaft 108 rotatable with respect to a motor housing 110. The motor housing 110 is considered a datum with respect to rotations and other motions of motor components. In use, the output shaft 108 can be coupled to the load 106, and the electric motor 102 can impart rotary power to the load 106 when electrically activated by appropriate electrical power and signals from the motor controller 104. In some implementations, the output shaft 108 extends through the motor 102 and is exposed at both ends, meaning that rotary power can be transmitted at both ends of the motor 102. Motor housing 110 can be symmetric about a rotation axis of output shaft 108, but the motor housing 110 may be of any external shape and can generally include means for securing the motor housing 110 to other structures to prevent rotation of the housing 110 during operation of the motor 102.
The electric motor 102 may include an active magnetic component 112, such as a stator, and a passive magnetic component 114, such as a rotor. In some implementations, for instance when a rotor has conductors or conductive elements being driven by an inverter or controllable power source, the rotor may be active. The stator, rotor, or both, may have an electrical circuit which is controlled to create an electromagnetic field in a position with respect to the opposing component(s) such that a mechanical force is produced between the components. For illustration purposes herein, in the illustrated implementation, a stator is used as a representative example of the active magnetic component 112 and rotor is used as a representative example of the passive magnetic component 114. In other implementations, the active magnetic component 112 and the passive magnetic component 114 may be other components of other electric machines or motors.
The electric motor 102 may also be described as including at least two magnetic components 112, commonly with a stationary component, or stator, and a component which is free to move 114, such as a rotary component, or rotor. The stator, rotor, or both, have an electrical circuit which is controlled to create an electromagnetic field in a position with respect to the opposing component(s) such that a mechanical force is produced between the components. For illustration purposes herein, in the present implementation, a stator is used as a representative example of the fixed magnetic component 112 and rotor is used as a representative example of the moveable magnetic component 114. In other implementations, the fixed magnetic component 112 and the moveable magnetic component 114 may be other components of other electric machines or motors. The rotor 114 is configured to electromagnetically interact with the stator 112 and can be disposed within the stator 112, e.g., in an internal rotor radial-gap motor, or parallel to the stator 112, e.g., in an axial-gap motor or in a linear motor, or outside of the stator 112 in an external rotor radial-gap motor, or some combination thereof. Electrical activity in the stator 112 drives motion of the rotor 114. The rotor 114 is rotationally coupled to the output shaft 108, such that any resultant rotation of the rotor is transmitted to the output shaft 108, causing the output shaft 108 to rotate. The stator 112 is fixed to the electric motor 102 such that during operation the rotor 114 moves about the stator 112 or parallel to the stator 112.
Electrical current flowing through a loop of electric wire or conductive elements results in a magnetomotive force (MMF) and a motor pole through the wound, or encircled, region of the wire or element. In a typical electric motor, such a loop is designed to have a sufficient diameter to carry the desired current load, which in some implementations should be thin enough such that a skin depth of the drive frequency fully penetrates the loop. In some implementations, many turns, or overlapping loops of wire, are used to increase the pole magnetic field strength. This topology may be referred to as a wound field pole. Such a set of overlapping loops is referred to as a coil.
For the purposes of this disclosure, a coil of electrical wire or conductive elements that is configured to act with other coils or conductive elements within an electrical machine, such as on the stator or rotor of an electric motor, are referred to as a “winding.” In practice, windings may take a variety of forms. For example, in some instances, a wire coil is wound together in series such that each turn of the coil has the same magnetic axis. Such coils wound in series or around individual rotor or stator teeth can be referred to as a “concentrated winding.” In some instances, coils can overlap and encompass multiple teeth of either a rotor or a stator. Such overlapping coils can be referred to as an armature or a “distributed winding.” A pole is a magnetic center of this distributed winding, and as such, the pole can move relative to the individual coils within such a distributed winding depending upon the drive current passing through the winding. In some instances, coils can be wrapped from the tooth slot around the yoke or back iron of either a rotor or a stator. Such coils can be referred to as a “toroidal winding.”
In the example electric motor 102 of
A plurality of stator teeth 214 extend radially from the stator core 202 and are oriented circumferentially around the stator core 202. An outer end 218 of the plurality of stator teeth 214 define an outer diameter 220 of the stator core 202. Each of the plurality of stator teeth 214 are configured to receive an opening of the plurality of coolant cans 204 (see
In some implementations, the stator core 202 (including the stator teeth 214) is comprised of a magnetically permeable material, such as iron. In some implementations, the stator core 202 is comprised of one or more cylinders having stator teeth formed on an outer surface. In some implementations, the stator core 202 is comprised of a plurality of stator plates or laminations that reduce eddy currents within the magnetically permeable material of the stator core 202. For example, in some implementations, stator laminations are included in portions of the stator core 202 that form the outer surface of the stator core 202.
In some implementations, the stator core 202 includes elements in addition to a magnetically permeable material. For example, in some implementations the stator core 202 includes adhesives and/or electrically insulating material (e.g., varnish and/or a metal oxide). In some implementations, portions of the stator core include or are encapsulated in epoxy or another insulating material.
Referring to
Referring to
In some implementations, the winding 250 includes elements besides electrical wire. For example, in various implementations, the winding 250 includes an adhesive or binding structure configured to hold together bundles of electrical wire of the winding 250 and/or a potting compound, such as a thermoplastic, configured to fill spaces between individual wires of the winding 250.
In some electrical machines, electrical insulation is required to prevent undesired conduction, or conduction of electrical current that is detrimental to the performance, safety, or lifespan of the system, within the electric machine. For instance, in an electric motor, insulation is required between the conductive elements and the magnetic components (see
Accordingly, in some implementations, the winding 250 includes one or more layers of insulation that enclose the electrical wires or conductive elements of the winding 250 within the interior compartment 232 of the coolant can 204, such that the winding 250 is electrically insulated from other components of the stator 200, other components of the electrical machine, and/or machines or machine components external to the electrical machine while being cooled by coolant flowing through the coolant can 232. Insulating material may include papers, plastics, varnishes, rubbers, or potting compounds that comprise some or all of the coolant can structure (see
The body 230 defines a fluid flow passage through the interior compartment 232 of the coolant can 204, such that when coolant is flowed into the interior compartment 232 of the body 230 via the one or more inlets 236 the coolant flows through gaps of the stator winding 250 (see
The cooling efficiency of windings 250 encapsulated in coolant cans 204 may be dependent on the volume of the interior compartment 232 of the coolant can 204 and the volume of the winding 250 disposed within the interior compartment. The more volume that the winding 250 has the less volume of coolant can flow through the interior compartment 232. In some implementations, a ratio between a volume of an interior compartment of a coolant can and a volume of one or more windings disposed therein is between 100:95 to 100:75. In some implementations, the ratio between the volume of the interior compartment of the coolant can and the volume of the one or more windings disposed therein is between 10:9 to 10:7. In some implementations, the ratio between the volume of the interior compartment of the coolant can and the volume of the one or more windings disposed therein is between 5:4 to 2:1. In some implementations, the ratio between the volume of the interior compartment of the coolant can and the volume of the winding is between 5:3 to 10:3.
In some implementations, the effectiveness of cooling the conductive elements may be described by the fluidic thickness established within the coolant can. While traditional thought would prescribe high amounts of fluid relative to conductors in order to adequately submerge and/or reject the requisite heat in operation, greater performance can be achieved by a thinner fluid thickness, or decreased fluidic volume with respect to conductor volume. In some implementations, the fluidic thickness within the interior compartment 232 of the coolant can 204 is in a range of about 0.2 mm to 0.7 mm. In some implementations, the fluidic thickness within the interior compartment 232 of the coolant can 204 is in a range of about 0.5 mm to 1.5 mm. In some implementations, the fluidic thickness within the interior compartment 232 of the coolant can 204 is in a range of about 1 mm to 3 mm. Interestingly, the clearance to minimize the peak coil temperature may not be the same as the clearance necessary to minimize Joule heating losses, which may benefit from the smallest possible clearance. In some applications, reducing peak temperature may be preferred (for instance, high power density applications). In other applications, reducing Joule heating losses may be preferred (for instance, highly efficient applications).
In some implementations, the interior compartment 232 of the coolant can 204 is not fully sealed from other components of the electric motor. For example, in some implementations, portions of two or more coolant cans 204 are in fluid connection with one another and form a partial seal between the interior compartments 232 of the two or more coolant cans 204. In some implementations, the coolant cans 204 may include openings defined in the body 230 of the coolant can in addition to the one or more inlets and outlets 236, 240, such that coolant may flow out of the coolant can 204 and contact other components of the electric motor. For example, one or more holes may be defined in the bottom wall 246 of the body 230 of the coolant can 204 such that when coolant flows through the interior compartment of 232 a volume of coolant may leak out through the one or more holes and come into contact with the stator core 202 or the rotor of the electric motor.
For example, in some implementations, less than 5% of the total volume of coolant that flows into the interior compartment 232 may leak out of the coolant can 204 through paths other than the one or more outlets 240 of the coolant can 204. In some implementations, less than 3% of the total volume of coolant that flows into the interior compartment 232 may leak out of the coolant can 204 through paths other than the one or more outlets 240 of the coolant can 204. In some implementations, less than 1% of the total volume of coolant that flows the interior compartment 232 may leak out of the coolant can 204 through paths other than the one or more outlets 240 of the coolant can 204.
For purposes of this disclosure, in some implementations wherein the coolant cans are configured to facilitate when small amounts of coolant to leak out of the coolant cans, as described above, the coolant cans are still “fluidically isolated” from the stator core or rotor, as defined in this disclosure.
Referring again to
Counter to traditional design wherein you attempt to utilize all of the available slot area for windings to maintain high performance, coolant cans may decrease conductor slot fill factor while still providing high performance operation or improving performance. This may increase the current density of the conductor within a machine which is typically associated with lower performance, but still offer performance enhancement as described throughout this application. In other applications, such as highly torque dense applications, coolant cans allow for added magnetic core material when compared to the requisite slot area of a traditional electric machine which enables the machine to lower saturation for the same magnetomotive force, as well as saturate at a higher level for additional electromagnetic performance.
Accordingly, in some implementations, the stator core 202 is configured such that each of the stator teeth 214 receive a coolant can 204, and thus, each of the stator teeth 214 are surrounded by one or more windings 250 encapsulated within the coolant can 204. In such implementations, two or more coolant cans 204 disposed circumferentially adjacent to each other may have a common wall between the bodies 230 of the coolant cans 204. In some implementations, a stator tooth 214 is surrounded by multiple windings 250. In some implementations, a single coolant can 204 spans across and is received by multiple stator teeth 214.
Referring again to
As mentioned above, in some electrical machines, it may be beneficial to have windings including coils that overlap and encompass multiple teeth of either a rotor or a stator, i.e., a distributed winding. Some stators or rotors according to this disclosure include distributed windings. In such implementations, because each winding is distributed across much or all of a circumference of the stator or rotor and is interwoven between multiple teeth, the coolant cans that define corresponding coolant flow passages in stators or rotors with distributed windings may have a different structure from those described for concentrated windings.
Moreover, in some electrical machines, it may be beneficial to have windings including coils that wrap a tooth slot of either a rotor or a stator around their respective back iron, i.e., a toroidal winding. Some stators or rotors according to this disclosure include toroidal windings (see
Referring to
Referring now to
A plurality of coolant can elements 350 are disposed circumferentially between the inner and outer rims 344, 346 of the endcaps 330, 332 and extend axially through the interior wall 342 of the endcaps 330, 332 of the coolant can frame 324. The coolant can elements 350 face radially inward toward the longitudinal axis 314 of the stator 300, such that an outer wall 354 of the coolant can element 350 is disposed radially within the outer diameter 336 of the endcaps 330, 332. The coolant can element 350 include a first side wall 356 and a second side wall 358, opposite the first side wall 356. An air gap opening 360 (see
Referring to
In some implementations, the stator core 326 is comprised of a magnetically permeable material, such as iron. In some implementations, the stator core 326 includes stator laminations that reduce eddy currents within the magnetically permeable material of the stator core 326. In some implementations, the stator core 326 includes elements besides a magnetically permeable material. For example, in some implementations the stator core 326 includes adhesives and/or an electrically insulating material (e.g., varnish and/or a metal oxide). In some implementations, portions of the stator core 326 include or are encapsulated in epoxy or another insulating material.
Referring to
In some implementations, the coolant can frame 324 is comprised of a single piece. In such implementations, the coolant can frame 324 may be overmolded within the stator core 326. In some implementations, the coolant can frame 324 is comprised of two or more pieces that are joined within the stator core 326. In such implementations, the two or more pieces or the coolant can frame 324 may be joined by one or more of a variety of methods, including ultrasonic welding, adhesives, and mating clips. These methods of joining pieces of the coolant can frame 324 may also be used to join other components of the coolant can frame as described herein.
Referring now to
Referring to
The endcap pieces 304, 306 include a plurality of openings 390 disposed circumferentially around the endcap pieces. In some implementations, the endcap pieces 304, 306 include the same number of openings 390. In some embodiments, first endcap piece 304 includes more openings 390 than the second endcap piece 306, or vice versa. In some embodiments, one of the endcap pieces 304, 306 includes no openings 390.
Referring now to
In some implementations, some coolant can elements 350 may not be in fluid communication with some other coolant can elements 350. In some implementations, some coolant can elements 350 are in fluid communication with only the interior compartment 392 of the first endcap 330 and some coolant can elements 350 are in fluid communication with only the interior compartment 394 of the second endcap 332.
In this implementation, the stator core 326 is fluidically isolated from the coolant flow through the interior compartments 384 of the coolant can elements 350 of the coolant can frame 324. Therefore, the stator core 326 may maintain a higher temperature during motor operation in comparison to conventional forced air, spray, or immersive cooling methods. In some implementations, the coolant can frame 324 is configured to provide coolant to the stator core 326 via additional outlets disposed in the interior compartment 384 of one or more coolant can elements 350 and/or in the interior compartments 392, 394 of the endcaps 330, 332.
In some implementations, the thermal management system having coolant cans for concentrated, distributed, or toroidal windings, as described above, may be applied to either a stator, a rotor, or both in an electrical machine. In some implementations, a stator of an electrical machine can have distributed windings and a rotor of an electrical machine can have concentrated windings, or vice versa. In some implementations, an electrical machine can include concentrated or distributed windings on components other than a stator or a rotor. In some implementations, an electrical machine other than an electric motor may include concentrated or distributed windings.
Some types of electrical machines may require concentrated windings having configurations different than the concentrated winding described with reference to
Referring to
Referring now to
The interior compartment 424 of the coolant can 404 is configured to encapsulate the toroidal winding 410, such that the toroidal winding 410 is fluidically isolated from the stator core 402 and other components of the electric motor. The assembled coolant can 404 includes an opening 430 disposed through the first and second pieces 420, 422 of the coolant can 404 and defines an interior wall 432 extending through the interior compartment 424 of the coolant can 404. The opening 430 of the coolant can 404 is configured to receive a stator segment 436 (see
For purposes of illustration, in
In some implementations, the conductors 450 of each winding 410 is in electrical connection with one or more other components of the thermal management system of the electric machine or other component components of the electric machine. For example, in some implementations, the conductors 450 of each winding 410 is in electrical connection with the conductors 450 of another winding 410 that may be encapsulated in a separate coolant can. In some implementations, the conductors 450 of each winding 410 is in electrical connection with a bus bar. In some implementations, the conductors 450 of each winding 410 is in electrical connection with an active electrical circuit.
The interior compartment 424 of the coolant can 404 defines a fluid flow passage, such that when liquid coolant is flowed into the interior compartment 424 of the coolant can 404 via the inlet 440 the coolant flows through the toroidal winding 410 and out the interior compartment 424 via the outlet 444 of the coolant can 404. In this implementation, the coolant can 404 is fluidically isolated from the stator core 402 such that flow of coolant through the interior compartment 424 of the coolant can 404 contacts the winding 410 but does not contact portions of the stator core 402.
Referring now to
Each stator segment 454 is further configured to mate with two other stator segments 454 disposed circumferentially adjacent to it, such that the assembled stator segments 454 form the stator core 402. In this implementation, the stator segment 454 includes a mating groove 480 and a mating recess 482. The stator 400 is assembled by inserting the mating groove 480 of one stator segment 454 with the mating recess 482 of another stator segment 454. When two stator segments 454 each having coolant cans 404 are mated, the coolant can 404 disposed on one stator segment 454 contacts the second inner side surface 472 and the second side surface 476 of the bottom portion of the other stator segment 454. The outer surfaces 468 of the stator segments 454 are configured to form a substantially continuous outer surface of the stator core 402 having a first diameter 490 (see
In some implementations, a ratio between the first and second diameters 490, 492 of the stator core 402 is in a range of 10:9 to 3:2. In some implementations, a ratio between the first and second diameters 490, 492 of the stator core 402 is in a range of 7:5 to 9:5. In some implementations, a ratio between the first and second diameters 490, 492 of the stator core 402 is in a range of 13:10 to 2:1. In some implementations, a ratio between the first and second diameters 490, 492 of the stator core 402 is in a range of 19:10 to 5:2.
In some implementations, the stator segments 454 that form the stator core 402 includes materials and laminations as described for stator cores throughout this disclosure, for example, stator core 326 of
Referring to
Referring now to
The interior compartment 524 of the coolant can 504 is configured to encapsulate the toroidal winding 510 such that the toroidal winding 510 is fluidically isolated from the stator core 502 and other components of the electric motor. The assembled coolant can 504 includes an opening 530 disposed through the first and second pieces 520, 522 of the coolant can 504 and defines an interior wall 532 extending through the interior compartment 524 of the coolant can 504. The opening 530 of the coolant can 504 is configured to receive a stator segment 536 (see
For purposes of illustration, in
In some implementations, the conductors 550 of each winding 510 is in electrical connection with one or more other components of the thermal management system of the electric machine and/or other component components of the electric machine. For example, in some implementations, the conductors 550 of each winding 510 is in electrical connection with the conductors 550 of another winding 510 that may be encapsulated in a separate coolant can. In some implementations, the conductors 550 of each winding 510 is in electrical connection with a bus bar. In some implementations, the conductors 550 of each winding 510 is in electrical connection with an active electrical circuit.
The interior compartment 524 of the coolant can 504 defines a fluid flow passage, such that when liquid coolant is inserted into the interior compartment 524 of the coolant can 504 via the inlet 540 the coolant flows through the toroidal winding 510 and out the interior compartment 524 via the outlet 544 of the coolant can 504. In this implementation, the coolant can 504 is fluidically isolated from the stator core 502 such that flow of coolant through the interior compartment 524 of the coolant can 504 contacts the winding 510 but does not contact the stator core 502 or the stator segments 536.
Referring now to
Each stator segment 554 is further configured to mate with two other stator segments 554 disposed circumferentially adjacent to it, such that the assembled stator segments 554 form the stator core 502. In this implementation, the stator segment 554 includes a first mating surface 580 and a second mating surface 582, configured to mate with the first mating surface 580. The stator 500 is assembled by inserting the first mating surface 580 of one stator segment 554 with the second mating surface 582 of another stator segment 554. Unlike the coolant cans 404 and the stator segments 454 of
In some implementations, a ratio between the first and second diameters 590, 592 of the stator core 502 is in a range of 10:9 to 3:2. In some implementations, a ratio between the first and second diameters 590, 592 of the stator core 502 is in a range of 7:5 to 9:5. In some implementations, a ratio between the first and second diameters 590, 592 of the stator core 502 is in a range of 13:10 to 2:1. In some implementations, a ratio between the first and second diameters 590, 592 of the stator core 502 is in a range of 19:10 to 5:2.
According to the present disclosure, the thermal management system including coolant cans for concentrated toroidal windings, as described above, may be applied to either a stator, a rotor, or both in an electrical machine. In some implementations, a stator of an electrical machine can have concentrated toroidal windings and a rotor of an electrical machine can have concentrated or distributed windings, or vice versa. In some implementations, an electrical machine can include concentrated toroidal windings on components other than a stator or a rotor.
As described throughout the present disclosure, it may be beneficial to provide a thermal management system for an electric motor including coolant cans on a rotor of the electric motor. Induced currents in windings of a rotor dissipate heat as described throughout this disclosure. Induced eddy currents in the rotor core represent loss of performance, such that it may be desirable to cool the rotor windings while maintaining the rotor core at a relatively high temperature to reduce eddy current generation. For example, one or more portions of the rotor core may have a higher temperature than one or more windings of the rotor during operation of the electric motor. Accordingly, in some implementations of the present disclosure, a rotor of an electric motor can include windings encapsulated by one or more coolant cans, rather than or in addition to coolant cans disposed on a stator of the electric motor.
Referring now to
A first endcap 622 is received by the first end 608 of the shaft 606 and a second endcap 624 is received by the second end 610 of the shaft 606. A plate 626 is disposed between each side of the coolant cans 612 and is configured to support the coolant cans 612 as the rotor 600 rotates. The coolant cans 612 are configured to encapsulate one or more windings 630 of the rotor 600 (see
Referring now to
The coolant can 612 includes an opening 642 extending through a top wall 644 and a bottom wall 646 of the coolant can 612. The opening 642 defines an interior wall 648 of the coolant can 612 and is configured to receive a lower portion 652 of a rotor pole 650.
The coolant can 612 includes an inlet 656 and an outlet 658 that are each in fluid communication with the interior compartment 640 of the coolant can 612. The interior compartment 640 defines a liquid flow path 660 such that when coolant is flowed into the interior compartment 640 via the inlet 656 the coolant flows through the winding 630 and out the interior compartment 640 via the outlet 658 of the coolant can 612.
The first endcap 622 is received by the first end 608 of the shaft 606 through a hole 668 of the endcap 622. A first collar 670 is disposed between the hole 668 of the first endcap 622 and the shaft 606. The first endcap 622 has an interior compartment 672 with a plurality of inlet holes 674 disposed circumferentially around the hole 668 that are in fluid communication with the interior compartment 672 of the first endcap 622. In this implementation, a plurality of outlet holes 676 are disposed at a radial distance from the hole 668 and are in fluid communication with the interior compartment 672 of the first endcap 622. The outlet holes 676 of the first endcap 622 are configured to couple with the inlets 656 of the coolant cans 612. In other implementations, the first endcap 622 includes a number of outlet holes 676 that is greater than a number of coolant cans 612 of the rotor 600. In some implementations, the first endcap 622 includes a number of outlet holes 676 that is less than a number of coolant cans 612 of the rotor 600.
Similarly, the second endcap 624 is received by the second end 610 of the shaft 606 through a hole 678 of the endcap 624. A second collar 680 is disposed between the hole 678 of the second endcap 624 and the shaft 606. The second endcap 624 has an interior compartment 682 with a plurality of outlet holes 684 disposed circumferentially around the hole 678 that are in fluid communication with the interior compartment 682 of the second endcap 624. In this implementation, a plurality of inlet holes 686 are disposed at a radial distance from the hole 678 and are in fluid communication with the interior compartment 682 of the second endcap 624. The inlet holes 686 of the second endcap 624 are configured to couple with the outlets 658 of the coolant cans 612. In other implementations, the second endcap 624 includes a number of inlet holes 686 that is greater than a number of coolant cans 612 of the rotor 600. In some implementations, the second endcap 624 includes a number of inlet holes 686 that is less than a number of coolant cans 612 of the rotor 600.
When the rotor 600 is assembled, the interior compartment 672 of the first endcap 622 is in fluid communication with the interior compartment 640 of each of the coolant cans 612 via the inlets 656 of the coolant cans 612 and the second endcap is in fluid communication with the interior compartment 640 of each of the coolant cans 612 via the outlets 658 of the coolant cans 612. Thus, the interior compartments 672, 682 of the first and second endcaps 622, 624 are in fluid communication with each other (see
A plurality of outlet holes 692 are disposed circumferentially on the shaft 606 near the first end 608 and extend into the first counterbore 688. The plurality of inlet holes 692 are configured to align with the inlet holes 674 of the first endcap 622, such that the first counterbore 688 is in fluid communication with the interior compartment 672 of the first endcap 622 when the rotor 600 is assembled. Likewise, a plurality of outlet holes 694 are disposed circumferentially on the shaft 606 near the second end 610 and extend into the second counterbore 690. The plurality of outlet holes 694 are configured to align with the outlet holes 684 of the second endcap 624, such that the second counterbore 690 is in fluid communication with the interior compartment 682 of the second endcap 624 when the rotor 600 is assembled. Thus, in this implementation, the first counterbore 688 is in fluid communication with the second counterbore 690 when the rotor 600 is assembled through the interior compartments 672, 682 of the endcaps 622, 624 and the interior compartments 640 of the coolant cans 612.
Still referring to
In some implementations, the rotor 600 is configured such that the main outlet of the rotor 600 is in fluid communication with the working volume of the motor. In some implementations, the coolant cans 612 include additional outlets in addition to the outlets 658 that are configured to facilitate flow of coolant out of the coolant can 612, other than through the outlets 658. For example, the coolant cans 612 can be configured to provide spray cooling of coolant to the stator (not shown) or other components of the motor.
In some implementations, it may be beneficial to provide a thermal management system that provides cooling to electrical components other than windings. For example,
In the illustrated example implementation of
Still referring to
In this implementation, an electrical component 750 is disposed within the through hole 712 of the shaft 706 between the plurality of inlet and outlet holes 792, 794 of the shaft 706, i.e. along the second flow path 732. Thus, the second portion of the volume of coolant flows toward and around the electrical component 750 and provides cooling to the electrical component 750 while the first portion of the volume of coolant provides cooling to the windings 630 within the coolant cans 612 of the rotor 600. This implementation may be beneficial because the second portion of the volume of coolant is not exposed to the high temperatures of the windings 630, which are cooled by the first portion of the volume of coolant.
In some implementations, the first and second portions of the volume of coolant have the same volume. In some implementations, the first portion of the volume of coolant is larger than the second portion of the volume of coolant, or vice versa. In some implementations, the through hole 712 of the shaft 706 has cross-sections with different diameters. For example, portions of the through hole 712 of the shaft 706 near the main inlets and outlets 720, 722 may have a larger diameter than a middle portion of the through hole 712 of the shaft 706 disposed between the aforementioned portions of the through hole 712, or vice versa.
In some implementations, the rotor 600 may include three or more parallel coolant flow paths through the rotor 600. Additionally, electrical components may be disposed within any coolant flow path through the rotor 600. For example, with reference to
Although this disclosure has provided example implementations in which a rotor is surrounded by a stator, in some implementations an external rotor and internal stator include coolant cans as described throughout this disclosure.
The stator and rotor implementations described throughout this disclosure are examples; in other implementations within the scope of this disclosure, various aspects of the systems for thermal management of an electric motor using coolant cans may be different. For example, a number of windings encapsulated by each coolant can, a number of inlets and/or outlets of each coolant can, a number of teeth included in each of the stator or rotor, and a number of teeth surrounded by each coolant can may be different from the examples shown throughout this disclosure. Shapes of the coolant cans, windings, stator core, and rotor core may be different from the shapes described throughout this disclosure.
In various implementations, coolant cans are comprised of, for example, plastic or another material resistant to corrosion by coolant and capable to withstand the elevated temperatures within the motor. In some implementations, the coolant cans are comprised of a thermally and/or electrically insulating material. In some implementations, the coolant cans are, for example, overmolded or insert-molded. In some implementations, the coolant cans are comprised of metal and/or a composite material. A thickness of one or more walls of the body of the coolant cans may be, in various implementations, at or below 0.15 mm. In other implementations, the thickness of the walls of the body of the coolant cans may be in a range of about 0.15 mm to 0.25 mm. In other implementations, the thickness of the walls of the body of the coolant cans may be in a range of about 0.25 to 0.5 mm. In other implementations, the thickness of the walls of the body of the coolant cans may be in a range of about 0.5 mm to 1.0 mm.
The coolant cans, or components thereof, and/or components of the stator and/or rotors described above may be formed through additive manufacturing techniques, such as by additive manufacturing. To that end, a number of additive manufacturing techniques may be implemented to form the coolant cans, such as vat photopolymerization, material jetting, binder jetting, powder bed fusion, material extrusion, directed energy deposition, and/or sheet lamination. In some embodiments, the coolant cans, or components thereof, may be additively manufactured directly upon a stator and/or a rotor. In some embodiments, a portion of a coolant can may be additively manufactured over a winding disposed in a bottom portion of the coolant can.
In some implementations, various electrical components may be electrically coupled or connected to one or more windings disposed in the stator, the rotor, the motor, and/or the motor assembly.
In some implementations, the discrete circuit component 800 includes a passive circuit component electrically coupled or connected to one or more windings disposed in the stator and/or rotor. In some implementations, the passive circuit component includes a diode or capacitor in certain non-limiting examples. In some implementations, the active circuit component includes one or more transistors. In some implementations, the discrete circuit component 800 includes an integrated circuit electrically coupled or connected to one or more windings disposed in the stator and/or rotor. In some implementations, the integrated circuit includes an active or passive frequency filter.
In some implementations, the discrete circuit component 800 includes a rectifier shorted to at least one winding of the rotor. The rectifier may serve to reduce current ripple in the winding of the rotor by introducing asymmetry into the winding's response to magnetic fields generated by windings of the stator, or to control the current or voltage within an electric machine either in the rotor, the stator, or both. In some implementations, these rectifiers may be included as auxiliary circuits within the electric machine. In some implementations, the rectifier may include a diode, e.g., a p-n junction diode, a gas diode, a Zener, or a Schottky diode. In some implementations, when a Schottky diode is included in the rectifier, the Schottky diode can be a silicon carbide diode. In some implementations, the rectifier includes an active circuit, such as an insulated-gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). In some implementations, the rectifier comprises an AC/DC rectifier that receives alternating current (AC) power from an AC power source, such as a utility grid or an external generator, and outputs direct current (DC) power to other components of the electric machine and/or to other machines or systems external to the electric machine. For example, the electric machine may be a generator that produces AC power via one or more windings of the generator that include one or more discrete circuit components comprising an AC/DC rectifier, which outputs DC power to an external electric machine, such as a rotor of an electric motor.
In some implementations, the discrete circuit component 800 includes an electrical switch electrically coupled or connected to one or more windings of the stator and/or rotor. The electrical switch may be configured to control electrical current to and/or from the one or more windings 810. In some implementations, the electrical switch includes a busbar in electrical connection to a power source. In some implementations, the electrical switch and busbar are encapsulated in one or more coolant cans with the one or more windings coupled thereto.
In some implementations, the discrete circuit component 800 comprises one or more switches or semiconductor devices coupled to one or more windings and arranged in an electrically conductive network. In such implementations, the plurality of switches or semiconductor devices arranged in an electrically conductive network, which may comprise a plurality of microinverters within a microinverter network, are included as part of an electric machine, for example an electric motor, that are in electrical connection with an electronic motor controller of the electric motor that may regulate the supply of current or voltage to the electric motor.
Current may pass through discrete circuit components 800 as well as through the windings 810 themselves, and thus, the discrete circuit components 800 may heat up during motor operation. Therefore, in some implementations, the discrete circuit components 800 may be encapsulated within one or more coolant cans with the one or more windings 810 coupled thereto, such that coolant contacts the winding and the one or more discrete circuit components 800. In this implementation, the discrete circuit components 800 may be cooled simultaneously with the windings 810. In some implementations, some discrete circuit components 800 and sub-components are encapsulated within the one or more coolant cans with the one or more windings coupled thereto while some discrete circuit components 800 and sub-components are not encapsulated within the coolant can of the one or more windings coupled thereto.
Various implementations of one or more inlets of coolant cans are within the scope of this disclosure. Besides fluidic inlets as described throughout this disclosure, one or more coolant can inlets in some implementations also function as ports for wires or other conductors, e.g., wires providing power to windings or carrying sensor signals. For example, with reference to
In some implementations, the coolant cans may include internal protrusions (e.g., internal walls, bumps, and/or ridges).
Still referring to
In some implementations, coolant cans are configured to have a smooth inner or outer surface, depending on whether the particular coolant can is disposed on the stator or rotor, that faces the air gap between the stator and the rotor of the electric motor. For example, as shown in
In some electrical machines, it may be desirable to provide a system and method for a thermal management system of the electrical machine that is configured to selectively provide cooling to some components of the machine while isolating such cooling from other components of the machine. For example, in conventional electric motor design, the temperature of the stator core and/or the rotor core (in which some windings may be disposed on) is maintained at a lower temperature than the temperature of the windings in order to create an effective thermal gradient for the motor windings. However, as the temperature of the motor core is reduced, the output performance of the electric motor may decrease, which is inverse to the relationship between the temperature of the windings and motor performance, as discussed above. This inverse relationship exists in conventional electric motor design because the stator core and/or the rotor core function similar to a heat sink by removing heat from the windings disposed thereon. Thus, in traditional motor designs, motor performance is typically increased via windings maintaining lower temperatures during motor operation. This is often achieved as a result of heat transferred from the winding to the stator core and/or rotor core directly and/or through the stator core and/or the rotor core to a liquid jacket. Thus, traditional methods of thermal management aim to cool both the core and the windings as discussed herein. However, motor performance can be increased and maintained to the extent that heat in the stator core and/or the rotor core can be maintained, as the core has greater performance at a higher temperature and the gradient is not required to be less than the winding. A undesired effect of conventional electric motor design is that the overall performance of the motor can be increased if the stator core and/or the rotor core is maintained at a temperature that is not dependent on cooling of the windings disposed thereon.
Electric machines having thermal management systems including coolant cans, according to the present disclosure, for example electric motors, do not require the stator core and/or the rotor core to facilitate cooling of the windings disposed thereon, and, therefore, can be operated at higher temperatures. In some implementations, the coolant cans can be configured to facilitate differential thermal management of one or more windings of a stator relative to the stator core of the stator and/or of one or more windings of a rotor relative to the rotor core of the rotor. For example, at the initial start of operation of the electric motor, where both the windings and the stator core and/or rotor core may be at the same relatively low temperature, it may be desirable to improve performance or efficiency of the motor to increase the temperature of the stator core and/or rotor core while cooling the windings disposed thereon.
To continue with this non-limiting example, the coolant cans may be configured to have a coolant flow passage that removes heat from the windings and transfers heat to the stator core and/or rotor core. In such implementations, under steady state continuous operating conditions, the winding temperature is on average equal to the average core temperature for the same operation condition, with stator core and/or rotor core temperature measured by direct thermo-probe and winding temperature measure by electrical resistance, or alternatively as a thermal gradient across the coolant can. In some implementations, a temperature of a winding is on average 5 degrees Celsius less than an average temperature of the stator core and/or rotor core disposed thereon. In some implementations, the temperature of the winding is on average 7.5 degrees Celsius less than the average temperature of the stator core and/or rotor core disposed thereon. In some implementations, the temperature of the winding is on average 10 degrees Celsius less than the average temperature of the stator core and/or rotor core disposed thereon. In some implementations, the temperature of the winding is on average 15 degrees Celsius less than the average temperature of the stator core and/or rotor core disposed thereon. In some implementations, the temperature of the winding is on average 20 degrees Celsius or more less than the average temperature of the stator core and/or rotor core disposed thereon.
For some electrical design and operation purposes it may be beneficial to electrically isolate one or more windings from other components or from the entire system in some electrical machines. For example, in some implementations, the coolant cans can be configured to facilitate electrical isolation of one or more windings from a stator core and/or rotor core. In some implementations, the coolant cans can be configured to be part of an insulator structure of an electric machine, the insulator structure being configured to electrically isolate one or more windings of the electric machine from other components of the machine or from electrical components outside of the machine.
In some implementations, a system for thermal management of an electric machine as described in this disclosure, for example an electric motor having coolant cans, may include temperature control modules that monitor and/or regulate coolant flow and temperature of the electric machine.
The temperature control module 900 may be coupled to the stator 904 and/or rotor 906 via couplings 910, 912, respectively. Couplings 910, 912 may be fluidic couplings and/or electrical couplings between the temperature control module 900 and the stator 904 and/or rotor 906, respectively. The stator 904 and the rotor 906 may be any of the stators and rotors described throughout this disclosure or any other stators and rotors not described in this disclosure.
The temperature control module 900 may include various sub-modules 920, each of which may be communicatively coupled to any or all of the other sub-modules 920.
In some implementations, the temperature control module 900 includes one or more temperature sensors 922 that are configured to measure temperatures in the stator 904 or rotor 906. For example, in some implementations, the temperature sensors 922 measure temperatures within one or more coolant cans disposed on the stator 904 and or rotor 906, thus, providing temperature data on windings encapsulated within the coolant cans. In some implementations, temperature sensors 922 measure temperatures of the stator core (e.g., of stator teeth or stator laminations) and/or of the rotor core (e.g., of rotor teeth or rotor laminations). In some implementations, the temperature sensors 922 are in direct fluid communication with the coolant (e.g., positioned inside coolant cans, or positioned on an inlet or outlet flow path to or from the coolant cans). In some implementations, the temperature sensors 922 include one or more of thermocouples, resistive temperature sensors, thermistors, and optical temperature sensors.
In some implementations, the electrical resistance of one or more windings may be measured to infer the future heating load of the rotor or stator on which the winding is mounted. The resistance may be measured by, for example, the motor controller 908, which may send a signal to a controller 930 of the temperature control module 900 to cause the controller 930 to increase or decrease coolant flow in accordance with the measured temperature. Because winding resistance may be a leading indicator of cooling needs (e.g., increased dissipated power in the windings is reflected in a higher winding resistance before coolant temperature would change measurably), this approach may provide more effective and/or more efficient cooling than waiting for a measured temperature to indicate a need to modify coolant flow.
In some implementations, the temperature control module 900 includes one or more flow sensors 924, located, for example, in the coolant cans, and/or in flow paths to and/or from the coolant cans (e.g., in a rotor shaft through which coolant flows). In some implementations, the flow sensors 924 measure a coolant flow rate. In some implementations, the flow sensors 924 measure a volume of coolant (e.g., to determine whether a coolant can is full of coolant).
In some implementations, the temperature control module 900 includes one or more pressure sensors 926 located, for example, in one or more coolant cans, or in flow paths to and/or from one or more coolant cans. The pressure sensors 926 may be configured to measure a fluid pressure of coolant flow for analysis by the temperature control module 900.
In some implementations, the temperature control module 900 and the stator 904 and/or rotor 906 are configured to maintain a positive pressure of coolant inside one or more coolant cans compared to a pressure outside the one or more coolant cans (e.g., compared to a pressure present in the air gap between the stator 904 and rotor 906). The presence of a positive pressure inside one or more coolant cans may reduce coolant backflow in comparison to the presence of an equal or negative pressure inside the one or more coolant cans, and may provide a constant flow of coolant through the one or more coolant cans. In addition, a positive coolant pressure inside one or more coolant cans may maintain full, or substantially full, coolant levels in the one or more coolant cans by reducing interrupted coolant flow inside the coolant cans as the motor operates and thereby increases the mechanical stability of the motor.
Coolant regulation features of the temperature control module 900 may include, in some implementations, one or more coolant pumps 950 and/or one or more flow regulators 952. The coolant pumps 950 are fluidically coupled to one or more inlets of one or more coolant cans (e.g., by tubes and/or pipes). In some implementations, the coolant pumps 950 are fluidically coupled to one or more outlets of one or more coolant cans, and thus, establishing a coolant flow loop. In some implementations, the flow regulators 952 may include, for example, valves, which can modulate flow and/or start or stop coolant flow through the valves. In some implementations, the coolant pump 950 is adjustable, for example, to increase or decrease an output pressure of coolant and/or to increase or decrease a coolant flow rate. In some implementations, separate pumps are used for the stator 904 and the rotor 906. In some implementations, the coolant pumps 950 and/or the flow regulators 952 are configurable by the controller 930 of the temperature control module 900. The controller 930 may include one or more processors 932, one or more storage devices 934, and one or more memory devices 936. In some implementations, the storage devices 934 and/or the memory devices 936 store machine-readable, non-transitory instructions implementing active control by the controller 930.
Flow regulators 952 may be implemented in software to control the flow rate of one or more coolant pumps 950. The control of the flow regulators 952 may be controlled in response to operating conditions in certain implementations, such as the duty cycle or predicted duty cycle of operation. This control may be achieved by a lookup table, multi-input/multi output (MIMO) controller, a plant model such as model predictive control (MPC).
In some implementations, the controller 930 receives a stream of temperature data from the one or more temperature sensors 922 and, in response, sends signals to the coolant pumps 950 and/or the flow regulators 952 to adjust coolant flow. A “stream” of data, as used herein, refers at least to an analog and/or digital electrical interpretable by the controller to indicate a corresponding measurement value and/or configuration.
For example, if a particular temperature sensor 922 indicates that a temperature of one or more windings of the stator 904 is above a threshold value, the controller 930 may send a control signal to a valve in fluid communication with the stator 904 and/or one or more coolant cans disposed on the stator 904 to cause increased coolant flow to the stator 904 (e.g., the control signal may cause the valve to switch to a more open configuration).
In some implementations, the controller 930 receives a stream of coolant flow data from the one or more flow sensors 924 and, in response, sends signals to the coolant pumps 950 and/or the flow regulators 952 to adjust coolant flow. For example, if a particular flow sensor 924 indicates that coolant flow through one or more coolant cans disposed on the rotor 906 is above a threshold value, the controller 930 may send a control signal to a valve to cause decreased coolant flow to the one or more coolant cans of the rotor 906.
In some implementations, the controller 930 receives a stream of coolant pressure data from the one or more pressure sensors 926 and, in response, sends signals to the coolant pumps 950 and/or the flow regulators 952 to adjust coolant pressure. For example, if a particular pressure sensor 926 indicates that a coolant flow passage within one or more coolant cans of the stator 904 is no longer at a positive pressure compared to a pressure within another volume of the motor 902, the controller 930 may send a control signal to a valve to cause increased coolant flow to the one or more coolant cans of the stator 904.
In some implementations, the controller 930 also receives, and send control signals in response to, other data. For example, in some implementations the controller 930 receives signals from the motor controller 908 indicating a change in motor condition (e.g., an imminent increase in speed of the motor 902), to which the controller 930 responds by sending corresponding control signals to match coolant flow conditions to the expected operating condition of the motor 902. This proactive approach may provide more effective and/or more efficient cooling than waiting for a measured temperature to indicate a need for, for example, increased coolant flow.
In some implementations, the motor controller 908 sends a stream to the controller 930 indicating the electrical resistance of one or more windings of the stator 904 and/or rotor 906, or sends a signal to the controller 930 indicating that the electrical resistance of one or more windings of the stator 904 and/or rotor 906 is, for example, above a threshold value. In response, the controller 930 may send signals to the coolant pumps 950 and/or the flow regulators 952 to adjust coolant flow.
Coolant flow control methods are not limited to the foregoing examples that make use of threshold values. In various implementations, coolant flow control methods may include continuous coolant flow response based on continuous input data (e.g., electrical resistance or temperature data). In some implementations, coolant flow control may include using machine learning to predict an anticipated need for coolant flow rate based on motor operation parameters, the machine learning algorithm executed by the one or more processors 932 of the controller 930 of the temperature control module 900 or the motor controller 908.
In some implementations, the temperature control module 900 includes a communication module 928, the communication module 928 configured to, for example, receive signals from and/or transmit signals to any of the sensors described above, the motor controller 908, or another device or signal source. In some implementations, the communication module 928 includes wireless communication devices, such as a near-field communication module, a Bluetooth module, a cellular communication module, and/or a WiFi communication module. In some implementations, the communication module 928 includes hardwired connections to components with which the communication module 928 is communicatively coupled.
In some implementations, the controller 930 of the temperature control module 900 is at least partially mechanical. For example, in some implementations the controller 930 implements coolant flow regulation at least partially by a mechanical response to readings of temperatures, pressures, and/or flow rates, rather than, or in addition to, by the computer processing of machine-readable instructions.
In some implementations, an electric machine as described in this disclosure, for example an electric motor having coolant cans, may include one or more coolant manifolds configured to regulate coolant flow within the electric machine.
In some implementations, the coolant pump 972 may be the one or more coolant pumps 950 that are configurable by the controller 930 of the temperature control module 900, as discussed above (see
In some implementations, the outlets of coolant cans disposed on the stator and/or the rotor may be configured to provide directed cooling to other components of the electric motor. For example, in some implementations, coolant cans are configured such that coolant, after flowing through the coolant cans of the stator and/or the rotor, enters the working volume of the electric motor (e.g., by outlets that drain directly into the working volume of the motor). In some implementations, the outlets of the coolant cans are positioned such that coolant flowing out of the coolant cans of the stator and/or the rotor enters a portion of the working volume in which the coolant will cause relatively few windage losses, such as a sump port positioned at the gravitational bottom of the motor and in fluidic communication with the working volume (see
In addition, in some implementations, outlets of the coolant cans are configured to direct coolant from the coolant cans to particular components of the motor, e.g., other components that increase in temperature during motor operation and may be desirable to cool. For example, in some implementations the coolant is directed out of the coolant can outlets to contact bearings of the motor, thereby cooling the bearings.
In some implementations, outlets of coolant cans disposed on the rotor may be configured to provide spray cooling to the stator windings. In some implementations, outlets of coolant cans disposed on the stator may be configured to provide spray cooling to the rotor windings. For example, with reference to
The various implementations described throughout this disclosure refer to flow of a coolant within an electric machine; in other implementations within the scope of this disclosure, various aspects of the coolant may be different. In some implementations, the liquid coolant comprises a mix of a coolant and a lubricant, configured to provide sufficient cooling to one or more windings encapsulated within one or more coolant cans while providing cooling and lubrication to other components of the electric machine outside of the coolant cans. In some implementations, the coolant is a gas configured to provide gaseous cooling to the one or more windings encapsulated within one or more coolant cans. In some implementations, one or more coolant cans includes two or more interior compartments that are fluidically isolated from each other and each having an inlet and an outlet, such that one interior compartment encapsulates one or more windings with an inlet configured to receive coolant while the inlet of one or more other interior compartments are configured to receive a flow of lubricant through the interior compartment to one or more outlets, which may be directed to other components of the electric machine. In such implementations, the thermal management system of the electric machine may include two or more separate fluid pumps, at least one configured to pump coolant and one configured to pump lubricant. In such implementations, the thermal management system may include a single fluid manifold in fluid connection with the two or more separate fluid pumps, such that the coolant and the lubricant pumped to the manifold are mixed in the manifold and while flowing to the one or more coolant cans.
Although some of the discussion above is framed in particular around thermal management systems, such as the various electric machines having thermal management systems including coolant cans, those of skill in the art will recognize therein an inherent disclosure of corresponding methods of use (or operation) of the disclosed systems, and the methods of installing the disclosed systems. Correspondingly, some non-limiting examples of the disclosure can include methods of using, making, and installing electric machines having thermal management systems including coolant cans.
Although some of the discussion above is framed in particular around systems, such as the various electric machines including winding coolant cans, those of skill in the art will recognize therein an inherent disclosure of corresponding methods of use (or operation) of the disclosed systems, and the methods of installing the disclosed systems. Correspondingly, some non-limiting examples of the disclosure can include methods of using, making, and installing electric machines including winding coolant cans.
For example, some implementations can include a method for thermal management of an electric machine having a thermal management system by flowing a coolant through an interior compartment of one or more coolant cans that encapsulate one or more windings or conductive elements of the electric machine within the interior compartment of the coolant can that is fluidically isolated from other components of the electric machine, such that the one or more windings have a lower temperature than other components of the electric machine. In an example implementation, with reference to
In some implementations, the method can further include detecting a temperature of the one or more windings encapsulated within the one or more coolant cans and determining whether the detected temperature is above a threshold value. Then flowing additional coolant through the interior compartment of the one or more coolant cans in response to determining that the detected temperature is above the predetermined threshold value. In an example implementation, with reference to
In some implementations, the method can further include detecting a pressure within the one or more coolant cans and the working volume of the electric machine. Determining whether the detected pressure within the one or more coolant cans is below the detected pressure within the working volume of the electric machine. Then applying a positive pressure, by a pump, within one or more of the coolant cans compared to the detected pressure of the working volume of the electric machine. In an example implementation, with reference to
Although the invention has been described and illustrated in the foregoing illustrative non-limiting examples, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the invention can be made without departing from the spirit and scope of the invention, which is limited only by the claims that follow. Features of the disclosed non-limiting examples can be combined and rearranged in various ways.
Furthermore, the non-limiting examples of the disclosure provided herein are not limited in application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other non-limiting examples and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
Also, the use the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “right”, “left”, “front”, “back”, “upper”, “lower”, “above”, “below”, “top”, or “bottom” and variations thereof herein is for the purpose of description and should not be regarded as limiting. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
Unless otherwise specified or limited, phrases similar to “at least one of A, B, and C,” “one or more of A, B, and C,” etc., are meant to indicate A, or B, or C, or any combination of A, B, and/or C, including combinations with multiple or single instances of A, B, and/or C.
In some non-limiting examples, aspects of the present disclosure, including computerized implementations of methods, can be implemented as a system, method, apparatus, or article of manufacture using standard programming or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a processor device, a computer (e.g., a processor device operatively coupled to a memory), or another electronically operated controller to implement aspects detailed herein. Accordingly, for example, non-limiting examples of the invention can be implemented as a set of instructions, tangibly embodied on a non-transitory computer-readable media, such that a processor device can implement the instructions based upon reading the instructions from the computer-readable media. Some non-limiting examples of the invention can include (or utilize) a device such as an automation device, a special purpose or general purpose computer including various computer hardware, software, firmware, and so on, consistent with the discussion below.
The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier (e.g., non-transitory signals), or media (e.g., non-transitory media). For example, computer-readable media can include but are not limited to magnetic storage devices (e.g., hard disk, floppy disk, magnetic strips, and so on), optical disks (e.g., compact disk (CD), digital versatile disk (DVD), and so on), smart cards, and flash memory devices (e.g., card, stick, and so on). Additionally, it should be appreciated that a carrier wave can be employed to carry computer-readable electronic data such as those used in transmitting and receiving electronic mail or in accessing a network such as the Internet or a local area network (LAN). Those skilled in the art will recognize many modifications may be made to these configurations without departing from the scope or spirit of the claimed subject matter.
Certain operations of methods according to the invention, or of systems executing those methods, may be represented schematically in the figures or otherwise discussed herein. Unless otherwise specified or limited, representation in the figures of particular operations in particular spatial order may not necessarily require those operations to be executed in a particular sequence corresponding to the particular spatial order. Correspondingly, certain operations represented in the figures, or otherwise disclosed herein, can be executed in different orders than are expressly illustrated or described, as appropriate for particular non-limiting examples of the invention. Further, in some non-limiting examples, certain operations can be executed in parallel, including by dedicated parallel processing devices, or separate computing devices configured to interoperate as part of a large system.
As used herein in the context of computer implementation, unless otherwise specified or limited, the terms “component,” “system,” “module,” etc. are intended to encompass part or all of computer-related systems that include hardware, software, a combination of hardware and software, or software in execution. For example, a component may be, but is not limited to being, a processor device, a process being executed (or executable) by a processor device, an object, an executable, a thread of execution, a computer program, or a computer. By way of illustration, both an application running on a computer and the computer can be a component. One or more components (or system, module, and so on) may reside within a process or thread of execution, may be localized on one computer, may be distributed between two or more computers or other processor devices, or may be included within another component (or system, module, and so on).
As used herein, the term, “controller” and “processor” and “computer” include any device capable of executing a computer program, or any device that includes logic gates configured to execute the described functionality. For example, this may include a processor, a microcontroller, a field-programmable gate array, a programmable logic controller, etc. As another example, these terms may include one or more processors and memories and/or one or more programmable hardware elements, such as any of types of processors, CPUs, microcontrollers, digital signal processors, or other devices capable of executing software instructions.
This application claims priority to U.S. Provisional Application No. 63/106,096, titled “Motors Including Coolant Cans,” filed on Oct. 27, 2020, which is hereby incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/US21/56917 | 10/27/2021 | WO |
Number | Date | Country | |
---|---|---|---|
63106096 | Oct 2020 | US |