ROTARY TRANSFORMER WITH INTEGRATED POWER ELECTRONICS

BACKGROUND OF THE INVENTION

A wound-rotor synchronous machine (WRSM) is an electric motor having a rotor and a stator. The stator is the fixed part of the machine, and the rotor is the rotating part of the machine. The stator usually has a multi-phase winding, and the rotor is made with a field winding instead of permanent magnets. The rotor spins in a magnetic field, and the magnetic field can be produced by the windings or field coils. A field coil is an electromagnet used to generate a magnetic field in an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. It includes a coil of wire through which a current flows. In the case of a machine with field coils, a current must flow in the coils to generate the field, otherwise no power is transferred to or from the rotor. The process of generating a magnetic field by means of an electric current is called excitation. Field coils yield the most flexible form of magnetic flux regulation and de-regulation, but at the expense of a flow of electric current.

Conventionally, the rotor windings of a WRSM can be powered or excited using a slip ring and brush assembly system. However, slip ring and brush assembly systems have disadvantages, including being inefficient at high speeds, frequently requiring maintenance, and being lossy overall, especially at high speeds due to the high contact resistances between the brush and the slip ring.

To avoid the shortcomings of slip ring and brush assembly excitation methods, wireless (or contactless) excitation systems or wireless power transfer systems have been developed. In general, wireless power transfer uses various technologies to transmit energy by means of electromagnetic fields (EMFs) without a physical link. In a wireless power transfer system, a transmitter device, driven by electric power from a power source, generates a time-varying EMF, which transmits power via mutual inductance (M) across space to a receiver device. The receiver device uses M to extract power from the EMF and supply the extracted power to an electrical load. Wireless power transfer provides power to electrical devices/loads where interconnecting wires are inconvenient, hazardous, or not possible. Wireless power techniques mainly fall into two categories, near-field and far-field. In near-field techniques, the time-varying EMF is generated using a variety of techniques, including resonant inductive coupling. Resonant inductive coupling is the near-field wireless transfer of electrical energy between magnetically coupled coils that are part of a resonant circuit tuned to resonate at the same frequency as the driving frequency.

Rotary transformers (RTs) are a type of wireless power transfer system that can be used for the controlled wireless excitation of the rotor windings of a WRSM. An RT performs the same general function as a conventional transformer in that both transfer electrical energy from one circuit to another at the same frequency but different voltages. A conventional transformer works on the principle of electromagnetic induction, i.e., the electromotive force is induced in the closed circuit due to the variable magnetic field around it. An RT differs from a conventional transformer in that the RT geometry is arranged so that the primary windings and the secondary windings can be rotated with respect to each other with negligible changes in the electrical characteristics. In a known configuration, the RT can be constructed by winding the primary and secondary windings into separate halves of a cup core. The concentric halves face each other, with each half mounted to one of the parts that rotate with respect to one another. Magnetic flux provides the coupling from one half of the cup core to the other across an air gap, providing the M that transfers energy from the RT's primary windings to its secondary windings.

Known approaches to using RT systems to provide excitation for a WRSM can include a resonant tuning network, which is also known as a compensation network. A resonant tuning network can include circuit components (e.g., various combinations of resistors, inductors and/or capacitors) that enable the associated transformer to store oscillating electrical energy similar to a resonant circuit and thus function as a band pass filter, allowing frequencies near their resonant frequency to pass from the primary to secondary winding, but blocking other frequencies. The amount of M between the primary and the secondary windings, together with the quality factor (Q factor) of the circuit, determines the shape of the frequency response curve. Resonant circuits are often calls LC or LRC circuits because of the inductive (L), resistive (R), and capacitive (C) components used to form the resonant circuit. In material science, every material has its own natural frequency. If the external vibration is equal to the natural frequency, resonance occurs. In electrical science, impedance of the inductors and capacitors depends on the frequency. Capacitive impedance is inversely proportional to frequency while inductive impedance is directly proportional to the frequency. At a particular frequency both cancel each other. Such a circuit is called as resonant circuit, and that particular frequency is resonant frequency.

In conventional RT systems that provides resonant tuning or compensation (i.e., a RT compensation system), the resonant tuning network (or compensation network) is provided on both the stationary (or stator, or primary) side and the rotating (or rotary, or secondary) side of the WRSM. For the primary coil, a basic function of “compensation” is minimizing the input apparent power and/or minimizing the voltage-ampere (VA) rating of the power supply. For the secondary coil, the compensation cancels the leakage inductance of the secondary coil in order to maximize the transfer capability.

In general, electric motors can be relatively complex structures with parts that rotate at high speeds and generate high temperatures. Additionally, the use of various forms of electromotive force, EMFs, complex communications signals, complex motor control operations, and the like, can add further complexity. Further, for many applications, the motor size and weight must be controlled. Thus, there is value in providing motor designs that prioritize providing compact size; reduced cost; simplicity in electrical, mechanical and thermal design; and reduced eddy current losses.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the disclosure provide an electric drive motor system that includes a stationary-side, a rotating-side, and a first mounting and communications structure on the rotating-side. A secondary is winding physically coupled to the first mounting and communications structure. A rectifier system is physically coupled to the first mounting and communication structure.

Embodiments of the disclosure provide a method of fabricating an electric drive motor system that includes forming a stationary-side, forming a rotating-side, and forming a first mounting and communications structure on the rotating-side. A secondary is winding physically coupled to the first mounting and communications structure. A rectifier system is physically coupled to the first mounting and communication structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram illustrating a non-limiting example of an electric drive motor system having integrated power electronics in accordance with aspects of the disclosure;

FIG. 2 is a simplified block diagram illustrating a non-limiting example of how the electric motor drive system shown in FIG. 1 can be implemented in accordance with aspects of the disclosure;

FIG. 3 is a simplified block diagram illustrating a three-dimensional (3D) view and a front-side view of a non-limiting example of how a portion of a rotating-side of an electric machine can be configured to include integrated power electronics in accordance with aspects of the disclosure;

FIG. 4 is a simplified block diagram illustrating a front-side view and a left-side view of a non-limiting example of how a portion of a rotating-side of an electric machine can be configured to include integrated power electronics in accordance with aspects of the disclosure;

FIG. 5 is a simplified block diagram illustrating a left-side view of a non-limiting example of how a portion of a rotating-side of an electric machine can be configured to include integrated power electronics in accordance with aspects of the disclosure;

FIG. 6 is a simplified flow diagram illustrating front-side view of a structure after fabrication operations for forming a portion of a rotating-side of an electric machine configured to include integrated power electronics in accordance with aspects of the disclosure;

FIG. 7 is a simplified flow diagram illustrating front-side view of a structure after fabrication operations for forming a portion of a rotating-side of an electric machine configured to include integrated power electronics in accordance with aspects of the disclosure; and

FIG. 8 is a simplified flow diagram illustrating front-side view of a structure after fabrication operations for forming a portion of a rotating-side of an electric machine configured to include integrated power electronics in accordance with aspects of the disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the disclosure provide a novel integrated power electronics system that can be used in an electric motor drive system having a wireless power transfer (or RT) network. The electric motor drive system can include an electric motor (e.g., a WRSM) having a stationary-side and a rotating-side. In embodiments of the disclosure, the integrated power electronics system can be implemented as an integrated mounting and/or communications structure with which selected portions of the motor and/or the wireless power transfer system can be integrated to provide improved physical support, improved electronic communications, and improved cooling. On the rotating-side, an instance of the integrated mounting and/or communications structure can be used to integrate secondary windings; rotating-side elements of the RT (if any); a rectifier; and various electronic connections between the secondary windings, the rotating-side elements of the RT, and the rectifier. On the stationary-side, an instance of the integrated mounting and/or communications structure can be used to integrate an inverter; stationary-side elements of the RT; primary windings; and various electronic connections between the inverter, the stationary-side elements of the RT, and the primary windings. In some embodiments of the disclosure, the integrated mounting and/or communications structure can be implemented as a multi-layered printed circuit board (PCB) operable to incorporate within its layers primary windings, secondary windings, transistors (e.g., for the inverter), diodes (e.g., for the rectifier), wiring, and the like. On the rotating-side where cooling is needed, the PCB can incorporate an assembly region operable to house certain components (e.g., diodes for the rectifier) and cooling mechanisms for the housed components.

Accordingly, the integrated mounting and/or communications structures (e.g., a PCB) described herein provide technical benefits and technical effects. The secondary windings and the rectifier subsystems are assembled in the same PCB structure, which significantly simplifies the design, prototyping, and production of the associated RT. Embodiments of the disclosure also mitigate or eliminate the difficulties in terminations and interconnections between the rectifier and the secondary winding assemblies. Embodiments of the disclosure further allow the assembly region (e.g., the assembly region that houses diodes of the rectifier) can be directly mounted on the motor shaft using aluminum support sleeve, which provides high mechanical robustness and simpler thermal management. Thus, in accordance with aspects of the disclosure, the integrated mounting and communications structure enables motor designs that prioritize compact size; reduced cost; simplicity in electrical, mechanical and thermal design; and reduced eddy current losses.

Turning now to a more detailed description of embodiments of the disclosure, FIG. 1 depicts a system 100 embodying aspects of the disclosure. The system 100 includes an energy source 110 electronically coupled to an electric motor drive system 102. The electric motor drive system 102 includes an inverter/RT system 120, an alternating-current (AC) excited motor 140, and a controller 170, configured and arranged as shown. In accordance with aspects of the disclosure, the inverter/RT system 120 includes an integrated mounting and communications structure 160 operable to integrate with an inverter system 122; an RT compensation system 124; electric connectors 128 operable to electrically couple the inverter system 122 to the RT compensation system 124; primary windings 126; and electric connectors 130 operable to electrically couple the RT compensation system 124 to the primary windings 126. In accordance with aspects of the disclosure, the DC excited motor 140 includes an integrated mounting and communications structure 162 operable to integrate with secondary windings 146; a rectifier system 142; and electric connectors 150 operable to electrically couple the secondary windings 146 to the rectifier system 142. Although the inverter/RT system 120, the DC excited motor 140, and the controller 170 are depicted as separate components, it is understood that the inverter/RT system 120, the DC excited motor 140, and the controller 170 can be configured and arranged in any suitable combination. For example, the controller 170 can be incorporated within the inverter/RT system 120; the inverter/RT system 120 can be incorporated within the DC excited motor 140; and/or the inverter/RT system 120 and the controller 170 can be incorporated within the DC excited motor 140.

The energy source 110 can be implemented in a variety of forms, including, for example as a battery. In some embodiments of the disclosure, the battery can be a battery pack having a set of one or more individual battery cells connected in series or in parallel and that operate under the control of one or more controllers, such as a battery control module (BCM) that monitors and controls the performance of the battery pack. The BCM can monitor several battery pack level characteristics such as pack current measured by a current sensor, pack voltage, and pack temperature, for example. The battery pack can be recharged by an external power source (not shown). The battery pack can include power conversion electronics operable to condition the power from the external power source to provide the proper voltage and current levels to the battery pack. The individual battery cells within a battery pack can be constructed from a variety of chemical formulations. Battery pack chemistries can include, but are not limited, to lead acid, nickel cadmium (NiCd), nickel-metal hydride (NIMH), lithium-ion or lithium-ion polymer.

The inverter 122 can be a resonant inverter 122 electrically coupled between the energy source 110 and the DC excited motor 140 to transfer excitation energy from the energy source 110 through the RT compensation system 124 and the primary windings 126 to the DC excited motor 140. More specifically, the resonant inverter 122 is operable to provide energy from the energy source 110 to the RT compensation system 124 at a desired resonant frequency for purposes of providing excitation through the primary windings 126 to the DC excited motor 140. In embodiments of the disclosure, the resonant inverter 122 is operable to convert the direct-current (DC) voltage from the energy source 110 to AC current at the desired resonant frequency as required by the DC excited motor 140 and the RT compensation system 124 for motor excitation. In embodiments of the disclosure, the resonant inverter 122 can be a full-bridge resonant inverter having four switches organized as two “phase legs.” Each phase leg can include two switches connected in series and between a positive DC rail and a negative DC rail. A phase node can be positioned between the two switches of each phase leg to provide the phases of an AC waveform output at a desired resonant frequency. In some embodiments of the disclosure, the resonant inverter 122 generates HF AC. The controller 170 is electronically coupled to the phase leg switches to control the on/off states of the switches, thereby controlling the frequency and phase of the AC waveform generated by the resonant inverter 122. The controller 170 includes a computing device, which includes a computer, a microprocessor, a digital signal processor, and the like, configured and operable to execute software commands and programs, and which can include associated firmware, such that the controller is configured and operable to control the on/off switching operations of the resonant inverter 122. The controller 170 is also configured to send various control commands to the DC excited motor 140 to control, for example, torque and/or speed of the motor 140.

The DC excited motor 140 can be any eclectic motor design that is suitable for the work to be performed by the motor. Examples of work that can be done by motors in conventional automobile-based motor applications include operating or moving power windows; power seats; fans for the heater and the radiator; windshield wipers; and/or the engine of a vehicle having a hybrid-electric vehicle configuration. Regardless of the type of the DC excited motor 140, it relies on electromagnetism and flipping magnetic fields to generate mechanical power. A conventional implementation of the DC excited motor 140 includes five basic parts, namely, a stator; a rotor; a solid axle; coils; and a so-called “squirrel cage.” The winding of the stator in an DC excited motor is a ring of electromagnets that are paired up and energized in sequence, which creates the rotating magnetic field. The rotor in an DC excited motor does not have any direct connection to a power source, and it does not have brushes. Instead, it often uses the previously-described squirrel cage. The squirrel cage in an DC excited motor is a set of rotor bars connected to two rings, one at either end. The squirrel cage rotor goes inside the stator. When excitation power is sent through the stator, it creates an EMF. The bars in the squirrel cage rotor are conductors, so they respond to the flipping of the stator's poles, which rotates the rotor and creates its own magnetic field. The key to an induction motor, where the field of the rotor is induced by the field of the stator, is that the rotor is always trying to catch up. It is always looking for stasis, so it is rotating to find that steady state. However, the EMF produced by the stator is always going to be a little faster than the rotor's field. The spin of the rotor is creating the torque needed to create mechanical power to turn the wheels of a car or the blades of a fan. Some DC excited motors use a wound rotor (e.g., a WRSM), which is wrapped with wire instead of being a squirrel cage. In either case, there is only one moving part in an DC excited motor, which means there are fewer things that need to be replaced or maintained.

As noted, in some embodiments of the disclosure, the DC excited motor 140 can be a WRSM. A WRSM is a rotating electric motor having a rotor and a stator. The stator is the fixed part of the machine, and the rotor is the rotating part of the machine. The stator usually has a multi-phase winding, and the rotor is made with a field winding instead of permanent magnets. The rotor spins in a magnetic field, and the magnetic field can be produced by the windings or field coils. In the case of a machine with field coils, an excitation current must flow in the coils to generate the field, otherwise no power is transferred to or from the rotor. Field coils yield the most flexible form of magnetic flux regulation and de-regulation, but at the expense of a flow of electric current. Conventionally, the rotor winding of a WRSM can be powered or excited with a slip ring and brush assembly. However, slip ring and brush systems have disadvantages, including being inefficient at high speeds, frequently requiring maintenance, and being lossy overall, especially at high speeds due to the high contact resistances between the brush and the slip ring systems.

To avoid the shortcomings of slip ring and brush assembly excitation methods, the RT compensation system 124, the primary windings 126, and the secondary windings 146 are operable to provide wireless excitation or wireless power transfer from a stator-side of the motor 140 to a rotor-side of the motor 140. In some embodiments of the disclosure, the RT compensation system 124 can be implemented as a specially designed only-stationary-side RT compensation system 124. In general, the RT is a circuit and method for wireless power transfer to the secondary windings of a WRSM for controlled excitation. An RT is essentially the same as a conventional transformer in that it transfers electrical energy from one circuit to another at the same frequency but different voltage. In general, a conventional transformer works on the principle of electromagnetic induction, i.e., the electromotive force is induced in the closed circuit due to the variable magnetic field around it. An RT differs from a conventional transformer in that the RT's geometry is arranged so that the primary windings and secondary windings can be rotated with respect to each other with negligible changes in the electrical characteristics. In a known configuration, the RT can be constructed by winding the primary and secondary windings into separate halves of a cup core. The concentric halves face each other, with each half mounted to one of the parts that rotate with respect to one another. Magnetic flux provides the coupling from one half of the cup core to the other across an air gap, providing the M that couples energy from the RT's primary windings to its secondary windings.

In conventional RT designs that provides resonant tuning or compensation (i.e., a RT compensation system), a resonant tuning network (or compensation network) is provided on both the stationary (or primary) side and the rotating (or secondary) side of the WRSM. RT designs that have resonant circuit components on both the stationary-side and the rotating-side of the WRSM are difficult to implement. For example, it is difficult to, in practice, place a resonant tuning network or compensation circuitry on the secondary-side due to very limited rotor space and the high-temperature rotor operating conditions that exceed the temperature rating of commercially available compact capacitors. Moreover, having a resonant tuning capacitor on the secondary-side increases the complexity of the rotating part, increases the mechanical mass, increases the inertia, and reduces mechanical reliability, especially at high rotational speeds.

The only-stationary-side implementation of the RT compensation system 124 addresses the difficulties associated with actually implementing (i.e., building and using) conventional RT designs that include double-sided compensation networks by providing the benefits of wireless power transfer without the difficulties associated with providing compensation circuitry on a rotating-side of an DC excited motor 140 (e.g., a WFSM). More specifically, the only-stationary-side implementation of the RT compensation system 124 is operable to deliver rotor excitation current from the primary windings 126 to the secondary windings 146 wirelessly, thereby eliminating the brush and slip ring maintenance issues, as well as the inefficiencies, fabrication challenges, and design drawbacks associated with brush and slip ring systems.

In aspects of the disclosure, the only-stationary-side implementation of the RT compensation system 124 accounts for having no resonant tuning capacitor on the secondary side by providing an extra resonant tuning capacitor (i.e., one of the resonant tuning capacitors C₁, C_f1of the only-stationary-side resonant LCC 124A shown in FIG. 2) on the primary side and adjusting the two primary side resonant tuning capacitors so that the uncompensated secondary side doesn't impose inefficiencies or other drawbacks on the RT system 124. In embodiments of the disclosure, an only-stationary-side LCC design methodology is provided that includes reflecting the impendence and/or inductance of the secondary side to the primary side, and the leakage inductance of this secondary coil (e.g., L₂shown in FIG. 2) is tuned on the primary side. In general, a reflected impedance (or inductance) is the part of the impedance of a circuit (e.g., circuit A) that is due to the influence another coupled circuit (e.g., circuit B). In embodiments of the disclosure, this can be accomplished by deriving the equivalent circuit models of the system 100, as well as the overall impedance model of the system 100, which allows the reflective impedance from the secondary to the primary to be computed. A further simplification is applied to the derived equivalent circuit models so the overall impedance seen by the resonant inverter 122 can be calculated. In order to tune this overall impedance to a unity power factor, a tuning capacitor (e.g., C₁shown in FIG. 2) of the LCC design is recalculated. Thus, the only-stationary-side implementation of the RT system 124 eliminates the need for capacitor tuning on secondary side, and the need for a secondary side resonant tuning capacitor(s) and tuning thereof, by providing additional primary side tuning components (e.g., a resonant tuning capacitor(s)) and adjusting the values of the tuning components on the primary side.

FIG. 2 depicts a system 100A having a vehicle battery 110A electronically coupled through a DC-link capacitor (C_dc) to an electric motor drive system 102A. The system 100A is a non-limiting example implementation of the system 100 (shown in FIG. 1); the vehicle battery 110A is a non-limiting example implementation of the energy source 110 (shown in FIG. 1); and the electric motor drive system 102A is a non-limiting example implementation of the electric motor drive system 102 (shown in FIG. 1). The electric motor drive system 102A can be implemented as a resonant inverter 122A electronically coupled to the controller 170 and a simplified representation of an electric machine 140A. The resonant inverter 122A is a non-limiting example implementation of the inverter 122 (shown in FIG. 1). The electric machine 140A is an example implementation of the DC excited motor 140 (shown in FIG. 1). The electric machine 140A includes a novel only-stationary-side resonant LCC 124A, stationary-side primary excitation windings L₁, rotating-side secondary excitation windings L₂, a rectifier 142A, and a rotor element represented by a rotor inductance L_rotorand a rotor resistance R_rotor. The novel only-stationary-side resonant LCC 124A is a non-limiting example implementation of the RT system 124 (shown in FIG. 1). The system 100A includes a stationary-side (e.g., stator-side) 220 and a rotating-side (e.g., a rotor-side) 230. In general, the stationary-side 220 includes the primary windings L₁and the circuit elements to the left thereof, and the rotating-side 230 include the secondary windings L₂and the circuit elements to the right thereof. In accordance with aspects of the disclosure, the stationary-side 220 includes the previously-described integrated mounting and communications structure 160 implemented as a printed circuit board (PCB) 160A operable to integrate with an inverter 122A; an only-stationary-side resonant LCC 124A; the various electric connectors that electrically couple the inverter 122A to the only-stationary-side resonant LCC 124A; primary windings L₁; and the various electric connectors that electrically couple only-stationary-side resonant LCC 124A to the primary windings L₂. In accordance with aspects of the disclosure, the rotating-side 230 includes the integrated mounting and communications structure 162 implemented as a PCB 162A and operable to integrate with the secondary windings L₂; a rectifier 142A; and the various electric connectors that electrically couple the secondary windings L₂to the rectifier system 142A.

Although the resonant inverter 122A, the electric machine 140A, and the controller 170 are depicted as separate components, it is understood that the resonant inverter 122A, the electric machine 140A, and the controller 170 can be configured and arranged in any suitable combination of components. For example, the controller 170 can be incorporated within the resonant inverter 122A; the resonant inverter 122A can be incorporated within the electric machine 140A; and/or the resonant inverter 122A and the controller 170 can be incorporated within the electric machine 140A.

Referring still to FIG. 2, the stationary-side 220 is configured to transfer power using inductive power transfer, and the rotating-side 230 is configured to receive power via inductive power transfer from the stationary-side 220. The stationary-side 220 includes a DC vehicle battery 110A, a DC link capacitor C_dc, a resonant inverter 122A, the only-stationary-side resonant LCC 124A, and the primary or stator-side coil L₁. The resonant inverter 122A receives a DC input signal from the vehicle batter 110A and converts the DC input signal to an AC output signal at a desired resonant frequency. In some embodiments of the disclosure, the resonant inverter 120A is a full bridge inverter circuit operable to include four power electronics switching device T₁, T₂, T₃, T₄, configured and arranged as shown. The switching devices T₁, T₂, T₃, T₄can be implemented in any suitable format, including but not limited to, metal oxide semiconductor field effect transistors (MOSFETs), BJTs, FETs, IGBTs, IGFETs, and the like. The inverter controller 170 is electrically coupled to each of the switching devices T₁, T₂, T₃, T₄to control the switching operation of the resonant inverter 120A. The inverter controller 170 turns the switching devices T₁, T₂, T₃, T₄on and off to generate the AC output signal V_{inv_0}at the desired resonant frequency. The inverter controller 170 includes a computing device (with memory), which includes a computer, a microprocessor, a digital signal processor, and the like, operable to execute software commands and programs, and which can include associated firmware, such that the controller 170 is configured and operable to control the on/off switching operations of the resonant inverter 120A. The controller 170 is also configured to send various control commands through the PCBs 160A, 162A to the DC excited motor 140A to control, for example, torque and/or speed of the motor 140A.

The only-stationary-side resonant LCC 124A interconnects the resonant inverter 122A with the primary or stator-side coil L₁. In the non-limiting example embodiment of the disclosure depicted in FIG. 2, the only-stationary-side resonant LCC 124A includes the primary or stator-side inductor L_f1, a stator-side series capacitor C₁, and a stator-side parallel capacitor C_f1. The primary or stator-side inductor L_f1and the stator-side series capacitor C₁are serially coupled together and coupled to a positive terminal of the primary or stator-side coil L₁, and stator-side parallel capacitor C_f1is coupled in parallel with the primary or stator-side coil L₁.

The rotating-side 230 includes a secondary or rotor-side coil L₂electrically coupled to a rectifier 142A. The secondary or rotor-side coil L₂is sufficiently close to the primary or stator-side coil L₁to be within an EMF generated by the primary or stator-side coil L₁such that M is between the primary or stator-side coil L₁and the secondary or rotor-side coil L₂. The secondary or rotor-side coil L₂uses M to generate an AC charging signal, and the rectifier 142A converts the AC charging signal to a DC charging signal (Irotor). In some embodiments of the disclosure, the rectifier 142A is a bridge rectifier circuit includes four diodes D₁, D₂, D₃, D₄. The DC charging signal is provided to a rotor of the electric machine 140A. The rotor is represented in FIG. 2 as the inductor L_rotorin parallel with the resistor R_rotor.

Energy is transferred through the M between the primary or stator-side coil L₁and the secondary or rotor-side coil L₂, but any L₁/L₂leakage inductance does not have a direct contribution to the active power transfer. Leakage inductance can be further undesirable because it causes the voltage to change with loading. In conventional approaches to decreasing leakage inductance and increasing M, a rotor-side compensation circuit (e.g., a rotor-side capacitive circuit/element) is provided on the rotating-side 230. However, for applications such as the system 100, 100A where the rotor-side rotates with respect to the stator-side, it is difficult to fabricate a rotor having a rotor-side compensation circuit. Embodiments of the disclosure avoid the need for the rotor-side compensation circuit/element by configuring and arranging the only-stationary-side resonant LCC 124A such that compensation that would in conventional RT designs be provided by a rotor-side compensation circuit/element on the rotating-side 230 is instead provided by the design and component values settings of the only-stationary-side resonant LCC 124A.

FIG. 3 depicts additional details of how the integrated mounting and communications structure 162, the secondary windings 146, the electric connectors 150, and the rectifier system 142 (all shown in FIG. 1) can be implemented as an integrated windings/rectifier 300 in accordance with aspects of the disclosure. FIG. 3 depicts a 3D-view and a front-side-view of the windings/rectifier 300, which includes a PCB mounting/communication element 310, a PCB-based secondary coil 312, a configuration of diodes 322 arranged as a rectifier circuit, a rectifier assembly 320, and a rotor shaft 324, configured and arranged as shown. In general, a rotor shaft is a central component of an electric motor. The rotor shaft is the carrier shaft for the laminated core of the rotor and thus transmits the electrically induced torque via a corresponding command from the controller 170 (shown in FIG. 2). The PCB mounting/communication element 310 is an example implementation of the integrated mounting and communications structure 162; the PCB-based secondary coil 312 is an example implementation of the secondary windings L₂; and the diodes 322 are configured to form a rectifier circuit that is an example implementation of the rectifier 142A. The PCB mounting/communications element 310 is a multi-layer PCB structure operable to incorporate in one or more of its layers the PCB-based secondary coil 312 (with or without a magnetic core), along with some or all of the electric connectors 150. In some embodiments of the disclosure, the rectifier diodes 322 can be incorporated within one or more layers of the PCB mounting/communications element 310. In some embodiments of the disclosure, the rectifier diodes 322 are spaced-apart from one another and mounted within a rectifier assembly 320 that is mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed surface of the PCB mounting/communications element 310. In accordance with aspects of the disclosure, the PCB mounting/communications element 310 and the rectifier assembly 320 are physically bonded to one another such that they function as a unitary structure that houses the PCB-based secondary coil 312, the rectifier diodes 322 and some or all of the electric connectors 150. In some embodiments of the disclosure, the rectifier assembly can be configured to include suitable thermal management elements operable to dissipate heat generated on the rotating-side 230 during operation of the electric motor 140, 140A. In some embodiments of the disclosure, the rectifier assembly 320 has an elongated cylindrical shape with a height dimension extending away from the PCB mounting/communications element 310. The elongated cylindrical shape and height dimension provide sufficient volume in the rectifier assembly 320 to house the previously-described suitable thermal management elements, along with some or all of the electric connectors 150.

FIGS. 4 and 5 depict alternative configurations of the windings/rectifier structure 400, 500, respectively. More specifically, FIG. 4 depicts a front-side-view and a left-side-view of the windings/rectifier 400 having a PCB mounting/communication element 410, a PCB-based secondary coil 412, a configuration of diodes 422 arranged as a rectifier circuit, a rectifier assembly 420, and a rotor shaft 424, configured and arranged as shown. The windings/rectifier structure 400 has substantially the same features and functionality as the windings/rectifier structure 300 (shown in FIG. 3) except the PCB mounting/communications element 410 is physically mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed outer surface of the rectifier assembly 420; and the rectifier assembly 420 is physically mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed outer surface of the rotor shaft 424.

FIG. 5 depicts a left-side-view of the windings/rectifier 500 having a PCB mounting/communication element 510, a PCB-based secondary coil 512, a configuration of diodes 522 arranged as a rectifier circuit, a rectifier assembly 520, and a rotor shaft 524, configured and arranged as shown. The windings/rectifier structure 500 has substantially the same features and functionality as the windings/rectifier structure 300 (shown in FIG. 3) except the PCB mounting/communications element 510 is physically mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed outer surface of the rotor shaft 524; and the rectifier assembly 420 is also physically mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed outer surface of the rotor shaft 524. In some embodiments of the disclosure, the rectifier assembly 520 is also physically mounted (e.g., through soldering or another suitable bonding mechanism) to an exposed surface of the PCB mounting/communications element 510.

FIGS. 6, 7, 8 and 4 depict examples of how the windings/rectifier 400 can be fabricated in accordance with aspects of the disclosure. Although, the fabrication operations focus on the windings/rectifier 400, substantially the same fabrication operations can be used to form the windings/rectifier 300 (shown in FIG. 3) and/or the windings/rectifier 500 (shown in FIG. 5). For the sake of brevity, conventional techniques related to making and using aspects of the disclosure may or may not be described in detail herein. In particular, various aspects of fabricating PCBs, electrical components, electronic connections, bonding techniques, and the like that can be used to implement the various technical features described herein are well known. Accordingly, in the interest of brevity, many conventional implementation details are only mentioned briefly herein or are omitted entirely without providing the well-known system and/or process details.

As shown in FIG. 6, known PCB fabrication techniques have been used to form the initial structures and layers of the PCB mounting/communications element 410 having an opening 602 for formation and attachment of the rotor shaft 424. As shown in FIG. 7, known fabrication techniques have been applied to form the PCB-based secondary coils 412 in one or more layers of the PCB mounting/communications element 410. Additionally, known fabrication techniques have also been used to form the electric connectors 150 (shown in FIG. 1) in one or more layers of the PCB mounting/communications element 410.

In embodiments of the disclosure, the PCB-based secondary coil 412 can be formed as a multi-turn conductive structure or trace on or in the PCB mounting/communications element 410 and extending around the opening 602 that will house the rotor shaft 424 (shown in FIG. 4). The PCB-based secondary coil 412 can be formed in one or more of the multiple layers of the PCB mounting/communications element 410. Some or all of the electric connectors 150 (shown in FIG. 1) can be formed in or on the PCB mounting/communications element 410 for electronically coupling the PCB-based secondary coil 412 to the diodes 422. Any suitable form (e.g., copper wire layers and the like) of interconnection mechanism can be used as the electric connectors 150.

As shown in FIG. 8, known fabrication techniques have been used to fabricate the rectifier assembly 420 having the diodes 422 and the previously-described features related portions of the electric connectors 150 and heat dissipation elements. Known fabrication techniques have been further used to physically mount (e.g., through soldering or another suitable bonding mechanism) the PCB mounting/communications element 410 to an exposed outer surface of the rectifier assembly 420. Finally, as shown in FIG. 4, known fabrication techniques have been used to physically mount (e.g., through soldering or another suitable bonding mechanism) the rectifier assembly 420 is to an exposed outer surface of the rotor shaft 424.

Although FIGS. 3-8 focus on an example implementation of the integrated mounting and communications structure 162, the secondary windings 146, the electric connectors 150, and the rectifier system 142 shown in FIG. 1, substantially the same structure options and fabrications option apply to the integrated mounting and communications structure 160, the inverter system 122, the electric connectors 128, the RT system 124, the electric connectors 130, and the primary windings 126 shown in FIG. 1.

Accordingly, it can be seen from the foregoing detailed description that the integrated mounting and/or communications structures (e.g., a PCB) described herein provide technical benefits and technical effects. The secondary windings and the rectifier subsystems are assembled in the same PCB structure, which significantly simplifies the design, prototyping, and production of the associated RT. Embodiments of the disclosure also mitigate or eliminate the difficulties in terminations and interconnections between the rectifier and the secondary winding assemblies. Embodiments of the disclosure further allow the assembly region (e.g., the assembly region that houses diodes of the rectifier) can be directly mounted on the motor shaft using aluminum support sleeve, which provides high mechanical robustness and simpler thermal management. Thus, in accordance with aspects of the disclosure, the integrated mounting and communications structure enables motor designs that prioritize compact size; reduced cost; simplicity in electrical, mechanical and thermal design; and reduced eddy current losses

The various components/modules of the systems illustrated herein are depicted separately for ease of illustration and explanation. In embodiments of the disclosure, the functions performed by the various components/modules/models can be distributed differently than shown without departing from the scope of the various embodiments of the disclosure describe herein unless it is specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

The diagrams depicted herein are illustrative. There can be many variations to the diagram or the steps (or operations) described therein without departing from the spirit of the disclosure. For instance, the actions can be performed in a differing order or actions can be added, deleted or modified. Also, the term “coupled” describes having a signal path between two elements and does not imply a direct connection between the elements with no intervening elements/connections therebetween. All of these variations are considered a part of the present disclosure.

The following definitions and abbreviations are to be used for the interpretation of the claims and the specification. As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains” or “containing,” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, a mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus.

Additionally, the term “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or designs. The terms “at least one” and “one or more” are understood to include any integer number greater than or equal to one, i.e. one, two, three, four, etc. The terms “a plurality” are understood to include any integer number greater than or equal to two, i.e. two, three, four, five, etc. The term “connection” can include both an indirect “connection” and a direct “connection.”

The terms “about,” “substantially,” “approximately,” and variations thereof, are intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application. For example, “about” can include a range of ±8% or 5%, or 2% of a given value.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.

While the disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

ROTARY TRANSFORMER WITH INTEGRATED POWER ELECTRONICS

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