The disclosure relates generally to heat generation. In particular aspects, the disclosure relates to a computer system and a method for heat generation in vehicles. The disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.
In vehicles, heating devices are used for a number of purposes and commonly a single vehicle is provided with several heating devices. A non-exhaustive list includes cabin heaters, engine block heaters, and exhaust gas heaters. When striving to minimize cost for production of a vehicle one approach is to remove as many redundant components as possible.
One solution to this problem is to use an electrical motor already present in the vehicle for heat generation. However, available methods based on this concept suffer from poor efficiency and limited accessibility during driving of the vehicle.
According to a first aspect of the disclosure, a computer system is provided. The computer system comprises processing circuitry configured to: obtain a maximum achievable flux linkage of an electrical machine, obtain a reference torque of the electrical machine based on the maximum achievable flux linkage, obtain a first set of d and q current values resulting in the reference torque, obtain a second set of d and q current values resulting the reference torque, and produce heat in the electrical machine by oscillating the d and q currents between the first and second set of current values while maintaining the reference torque. The first aspect of the disclosure may seek to efficiently provide heat generation by the electrical machine also during normal operation of the electrical machine. A technical benefit may include allowing the currents to oscillate for increased heat generation in the stator of the electrical machine, which is beneficial if the machine is cooled by a liquid coolant in the housing. Further, a pulsating field in the rotor will heat the magnets of the electrical machine. This is especially important when dealing with permanent magnet materials that easily demagnetize at cold temperatures. Further, precise control over the torque is enabled by following the iso-torque line with all current combinations which are allowed considering the voltage and current constraints. It is also possible to impose time-varying fields in the stator and rotor while still maintaining a constant torque, as well as making it possible to heat magnets and the rotor in a controlled fashion, also during driving.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain the maximum achievable flux linkage based on the angular frequency of the electrical machine. A technical benefit may include a simple approach to a speed dependent flux constraint for the dq currents.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain the maximum achievable flux linkage as
where UDC is the terminal voltage of the electrical machine. A technical benefit may include a simple approach to adding a voltage constraint for the dq currents.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain a maximum torque of the electrical machine based on the maximum achievable flux linkage, and crop the reference torque of the electrical machine based on the maximum torque. A technical benefit may include preventing over voltage of the electrical machine.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain the first set of d and q current values as a maximum d current value and a maximum q current value. A technical benefit may include using a first reference set of dq currents corresponding to a maximum limit for the currents, thereby increasing the current span.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain the second set of d and q current values as a minimum d current value and a minimum q current value. A technical benefit may include using a second reference set of dq currents corresponding to a minimum limit for the currents, thereby maximizing the current span.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain a normalized current factor of the electrical machine based on the normalized reference torque. A technical benefit may include a simple parameter allowing for fast reference and lookup in associated current tables.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain a cropped normalized current factor based on the normalized reference torque. A technical benefit may include a further increase in processing speed when obtaining the reference currents.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: oscillate the d and q currents between the first and second set of current values by a frequency of 10-50 Hz, preferably by a frequency of 15-25 Hz. A technical benefit may include a robust and efficient heat generation.
Optionally in some examples, including in at least one preferred example, the processing circuitry is further configured to: obtain the maximum achievable flux linkage based on the angular frequency of the electrical machine, obtain the maximum achievable flux linkage as
where UDC is the terminal voltage of the electrical machine, obtain a maximum torque of the electrical machine based on the maximum achievable flux linkage, crop the reference torque of the electrical machine based on the maximum torque, obtain the first set of d and q current values as a maximum d current value and a maximum q current value from a current reference lookup table, obtain the second set of d and q current values as a minimum d current value and a minimum q current value from a current reference lookup table, obtain a normalized current factor of the electrical machine based on the normalized reference torque, obtain a cropped normalized current factor based on the normalized reference torque, and oscillate the d and q currents between the first and second set of current values by a frequency of 10-50 Hz, preferably by a frequency of 15-25 Hz, thereby producing heat in windings and/or a stator of the electrical machine.
According to a second aspect of the disclosure, a vehicle is provided. The vehicle comprises the computer system of the first aspect.
Optionally in some examples, including in at least one preferred example, the vehicle comprises: an electrical machine, and a heat generation system configured to transmit a request for increased heat generation to the computer system. A technical benefit may include using the electrical machine to produce heat, thereby reducing the need for extra heating devices of the vehicle.
According to a third aspect of the disclosure, a computer-implemented method is provided. The computer-implemented method comprises: obtaining, by processing circuitry of a computer system, a maximum achievable flux linkage of an electrical machine, obtaining, by the processing circuitry, a reference torque of the electrical machine based on the maximum achievable flux linkage, obtaining, by the processing circuitry, a first set of d and q current values resulting in the reference torque, obtaining, by the processing circuitry, a second set of d and q current values resulting the reference torque, and producing, by the processing circuitry, heat in the electrical machine by oscillating the d and q currents between the first and second set of current values while maintaining the reference torque. The third aspect of the disclosure may seek to efficiently provide heat generation by the electrical machine also during normal operation of the electrical machine. A technical benefit may include allowing the oscillating currents to increase the heat generation in the stator of the electrical machine, which is beneficial if the machine is cooled by a liquid coolant in the housing.
Optionally in some examples, including in at least one preferred example, the method further comprises: obtaining, by the processing circuitry, the maximum achievable flux linkage based on the angular frequency of the electrical machine. A technical benefit may include a simple approach to a speed dependent flux constraint for the dq currents.
Optionally in some examples, including in at least one preferred example, the method further comprising: obtaining, by the processing circuitry, a maximum torque of the electrical machine based on the maximum achievable flux linkage, and cropping, by the processing circuitry, the reference torque of the electrical machine based on the maximum torque. A technical benefit may include preventing over voltage of the electrical machine.
Optionally in some examples, including in at least one preferred example, the method further comprising: obtaining, by the processing circuitry, the first set of d and q current values as a maximum d current value and a maximum q current value. A technical benefit may include using a first reference set of dq currents corresponding to a maximum limit for the currents, thereby increasing the current span.
Optionally in some examples, including in at least one preferred example, the method further comprising: obtaining, by the processing circuitry, the second set of d and q current values as a minimum d current value and a minimum q current value. A technical benefit may include using a second reference set of dq currents corresponding to a minimum limit for the currents, thereby maximizing the current span.
According to a fourth aspect of the disclosure, a computer program product is provided. The computer program product comprises program code for performing, when executed by the processing circuitry, the method of the third aspect.
According to a fifth aspect of the disclosure, a non-transitory computer-readable storage medium is provided. The non-transitory computer-readable storage medium comprises instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of the third aspect.
The disclosed aspects, examples (including any preferred examples), and/or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.
There are also disclosed herein computer systems, control units, code modules, computer-implemented methods, computer readable media, and computer program products associated with the above discussed technical benefits.
The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.
The examples presented herein provide a solution to use an electrical machine of a vehicle to generate heat in a controlled manner. For a requested torque, the electrical machine is controlled by selecting d and q current values on the same iso-torque curve, and by oscillating the d and q currents between the selected values to generate excessive heat in the electrical machine. This heat can be utilized by other components of the vehicle, thereby allowing a reduction of heating capacity of the existing components or even allowing one or more dedicated heating components to be removed from the vehicle architecture. In particular, control of the electrical machine is performed by considering a voltage limit which is used to crop the d and q current values, thereby allowing heat to be generated also at higher speeds of the electrical machine.
The vehicle 1 comprises, at least to some extent, processing circuitry 110 forming part of a computer system 100 (see
The vehicle 1 may further comprise communications circuitry 90 configured to receive and/or send communications. The communications circuitry 90 may be configured to enable the vehicle 1 to communicate with one or more external devices or systems such as a cloud server 20. The communication with the external devices or systems may be directly or via a communications interface such as a cellular communications interface 30, such as a radio base station. The cloud server 20 may be any suitable cloud server exemplified by, but not limited to, Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), IBM Cloud, Oracle Cloud Infrastructure (OCI), DigitalOcean, Vultr, Linode, Alibaba Cloud, Rackspace etc. The communications interface may be a wireless communications interface exemplified by, but not limited to, Wi-Fi, Bluetooth, Zigbee, Z-Wave, LoRa, Sigfox, 2G (GSM, CDMA), 3G (UMTS, CDMA2000), 4G (LTE), 5G (NR) etc. The communication circuitry 90 may, additionally or alternatively, be configured to enable the vehicle 1 to be operatively connected to a Global Navigation Satellite System (GNSS) 40 exemplified by, but not limited to, global positioning system (GPS), Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), Galileo, BeiDou Navigation Satellite System, Navigation with Indian Constellation (NavIC) etc. The vehicle 1 may for example be configured to utilize data obtain from the GNSS 40 to determine a geographical location of the vehicle 1.
The vehicle 1 in
With reference to
The dq frame is a mathematical tool used to simplify the analysis and control of electrical machines, such as electric motors or generators.
The dq frame is a coordinate system that rotates with the rotor of the electrical machine, with the d-axis aligned with the magnetic field from the permanent magnets in the rotor, i.e. the magnetization field, and the q-axis 90 degrees ahead of the d-axis. By transforming the three-phase electrical quantities of the machine (i.e. with regards to voltage and current) from the stationary orthogonal frame to the rotating dq frame, it is possible to represent the behavior of the electrical machine as a set of two variables, i.e. the direct-axis (d-axis) and the quadrature-axis (q-axis) components.
The d-axis and the q-axis components may represent any electrical or magnetic quantity (such as current, voltage, or flux) that changes in a three-phase system when the phases are shifted 120 degrees in space and time.
Using the dq frame, it is possible to control the behavior of the electrical machine with regards to speed and torque output by manipulating the d-axis and q-axis components of the voltage and current.
A commonly used way to control electrical machines is called field-oriented control (FOC). FOC involves adjusting the d-axis and q-axis components to control the machine's magnetic field. By adjusting these components in real-time, it is possible to maintain a desired speed or torque output from the machine.
FOC typically requires the position of the rotor as an input. For this purpose, a resolver may be arranged at the rotor shaft, providing resolver signals indicative of the position of the rotor.
In
The heat generation system 200 is configured to provide control signals Iqref, Idref for field-oriented control of the electrical machine 10. The motor control system 12 is configured to receive the control signals Iqref, Idref for providing the desired control of the electrical machine 10. The motor control system 12 comprises a transformation circuitry 13 configured to measure and transform the motor phase currents to the dq frame, resulting in measured dq frame currents Id and Iq. These transformed currents Id and Iq are compared to the control signals Idref and Iqref (i.e. the flux reference and the torque reference) by regulators 14a, 14b, outputting reference voltages Vdref and Vqref in the dq frame. An inverse transformation circuitry 15 is configured to invert the reference voltages Vdref and Vqref to the voltage components Varef and Vβref of the stator vector voltage in the stationary orthogonal reference frame. These reference voltages are inputs to a space vector pulse-width modulator 16 which is configured to provide drive signals to an inverter 17.
Each of the transformation circuitry 13 and the inverse transformation circuitry 15 may require information of the position of the rotor 11b, which may be provided from the resolver 11a.
Assuming this, the maximum achievable flux linkage that can be linked with the stator windings without causing an over voltage is estimated by
where ω is the electrical angular frequency of the electrical machine 10.
The heat generation system 200 further comprises a torque obtainer 220. The torque obtainer 220 is configured to obtain a reference torque T*crop of the electrical machine 10 based on the maximum achievable flux linkage {circumflex over (ψ)} obtained by the flux linkage obtainer 210. For this, a torque command may be received by the torque obtainer 220, corresponding to a requested torque T* of the electrical machine 10. The torque obtainer 220 may receive the maximum achievable flux linkage {circumflex over (ψ)} from the flux linkage obtainer 210 and use this as input to a flux linkage/torque lookup table 222. The flux linkage/torque lookup table 222 will return a value corresponding to the maximum torque T*max of the electrical machine 10 given the achievable flux linkage {circumflex over (ψ)}. From the requested torque T* and the maximum torque T*max the torque obtainer 220 will output a reference torque T*crop to be used for control of the electrical machine 10; if the maximum torque T*max is lower than the requested torque T*, the requested torque T* will be cropped such that the resulting reference torque T*crop equals T*max.
The flux/torque lookup table 222 may be stored locally or remotely with reference to the heat generation system 200. In the shown example the flux/torque lookup table 222 forms part of the heat generation system 200; in another example the heat generation system 200 is in communication with the flux/torque lookup table 222.
The flux/torque lookup table 222 may be created by first defining the flux levels in an equidistant vector. The maximum torque is then derived for each flux level using the following equations:
Equation (2) is here a cost function, where ψPM(id, iq), Lq(id, iq) and Ld(id, iq) in (4) can be found using separate lookup tables.
Equations (3) and (4) act as constraints for the cost function defined by Equation (2).
The torque obtainer 220 is also determining a normalized reference torque T*norm. For example, the normalization may be done with regards to a scale of 0 to 1, where 0 corresponds to the lowest possible torque of the electrical machine 10 while 1 corresponds to the maximum possible torque of the electrical machine 10. If considering a positive scale only, 0 may correspond to zero torque. If the resulting reference torque T*crop is 80% of the maximum possible torque of the electrical machine 10, the normalized reference torque T*norm would be 0.8.
The heat generation system 200 further comprises a factor obtainer 230. The factor obtainer 230 is configured to obtain a factor k* that corresponds to an interval of valid positions on the iso-torque line for a given torque. For explaining this further, reference is made to
In the dq coordinate system, the currents that oscillate with the synchronous frequency with a constant amplitude will appear as constant quantities. Consequently, a conventional PI controller can be used to reach the defined references accurately. The dq currents can be calculated if the phase currents and the rotor position are available:
Where θ is the rotor's angular position in relation to when the permanent magnet flux is aligned with phase A. The dq current together with the permanent magnet flux and the dq inductances give the torque as
Several lines are drawn in the diagrams in
Now considering the diagram of
Again referring to
The heat generation system 200 further comprises a d and q current value obtainer 240. The d and q current value obtainer 240 is configured to obtain, based on the cropped reference torque T*crop and based on the cropped factor k*crop, the minimum and maximum d current values Idmax, Idmin for obtaining the cropped reference torque T*crop. The d and q current value obtainer is further configured to obtain the minimum and maximum q current values Iqmax, Iqmin. These d and q current values may be obtained by calling a current value lookup table 242 using the cropped reference torque T*crop and the minimum/maximum of the cropped factor k*crop as input, and the current value lookup table 242 will return the minimum and maximum d and q current values.
Hence, the d and q current value obtainer 240 obtains a first set of d and q current values Idmax, Idmin resulting in the reference torque T*crop, and a second set of d and q current values Iqmax, Iqmin resulting in the same reference torque T*crop. Optionally, the q current values can be obtained from looked up d current values and the reference torque T*crop.
The heat generation system 200 further comprises an oscillator 250 being configured to produce heat in the electrical machine 10 by oscillating the d and q currents between the first and second set of current values while maintaining the reference torque T*crop.
To find the corresponding q current value for each torque and d current, the objective function can be formulated as:
Examples of simulations are shown in
The speed and torque results from the simulations are visualized in the upper two diagrams. In addition, the current references are found in the bottom two diagrams. The resulting torque follows the reference well even though the current references and the resulting currents oscillate. When the speed increases the ranges of the currents are decreased. Eventually the speed becomes so high that the algorithm must derate the torque. In this instant only one current combination that creates the derated torque reference can be realized, and the dq currents become constant. When the speed decreases the torque reference is no longer derated and the current references start to oscillate once more when a range of current combinations can be realized.
The computer system 500 may comprise at least one computing device or electronic device capable of including firmware, hardware, and/or executing software instructions to implement the functionality described herein. The computer system 500 may include processing circuitry 502 (e.g., processing circuitry including one or more processor devices or control units), a memory 504, and a system bus 506. The computer system 500 may include at least one computing device having the processing circuitry 502. The system bus 506 provides an interface for system components including, but not limited to, the memory 504 and the processing circuitry 502. The processing circuitry 502 may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory 504. The processing circuitry 502 may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processing circuitry 502 may further include computer executable code that controls operation of the programmable device.
The system bus 506 may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and/or a local bus using any of a variety of bus architectures. The memory 504 may be one or more devices for storing data and/or computer code for completing or facilitating methods described herein. The memory 504 may include database components, object code components, script components, or other types of information structure for supporting the various activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory 504 may be communicably connected to the processing circuitry 502 (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory 504 may include non-volatile memory 508 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory 510 (e.g., random-access memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with processing circuitry 502. A basic input/output system (BIOS) 512 may be stored in the non-volatile memory 508 and can include the basic routines that help to transfer information between elements within the computer system 500.
The computer system 500 may further include or be coupled to a non-transitory computer-readable storage medium such as the storage device 514, which may comprise, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device 514 and other drives associated with computer-readable media and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, and the like.
Computer-code which is hard or soft coded may be provided in the form of one or more modules. The module(s) can be implemented as software and/or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device 514 and/or in the volatile memory 510, which may include an operating system 516 and/or one or more program modules 518. All or a portion of the examples disclosed herein may be implemented as a computer program 520 stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device 514, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processing circuitry 502 to carry out actions described herein. Thus, the computer-readable program code of the computer program 520 can comprise software instructions for implementing the functionality of the examples described herein when executed by the processing circuitry 502. In some examples, the storage device 514 may be a computer program product (e.g., readable storage medium) storing the computer program 520 thereon, where at least a portion of a computer program 520 may be loadable (e.g., into a processor) for implementing the functionality of the examples described herein when executed by the processing circuitry 502. The processing circuitry 502 may serve as a controller or control system for the computer system 500 that is to implement the functionality described herein.
The computer system 500 may include an input device interface 522 configured to receive input and selections to be communicated to the computer system 500 when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processing circuitry 502 through the input device interface 522 coupled to the system bus 506 but can be connected through other interfaces, such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) 1394 serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system 500 may include an output device interface 524 configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 500 may include a communications interface 526 suitable for communicating with a network as appropriate or desired.
The operational actions described in any of the exemplary aspects herein are described to provide examples and discussion. The actions may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the actions, or may be performed by a combination of hardware and software. Although a specific order of method actions may be shown or described, the order of the actions may differ. In addition, two or more actions may be performed concurrently or with partial concurrence.
Example 1: A computer system comprising processing circuitry configured to: obtain a maximum achievable flux linkage ({circumflex over (ψ)}) of an electrical machine (10), obtain a reference torque (T*crop) of the electrical machine (10) based on the maximum achievable flux linkage ({circumflex over (ψ)}), obtain a first set of d and q current values (Idmax, Iqmax) resulting in the reference torque (T*crop), obtain a second set of d and q current values (Idmin, Iqmin) resulting the reference torque (T*crop), and produce heat in the electrical machine (10) by oscillating the d and q currents between the first and second set of current values (Idmax, Iqmax, Idmin, Iqmin) while maintaining the reference torque (T*crop).
Example 2: The computer system of Example 1, wherein the processing circuitry is further configured to: obtain the maximum achievable flux linkage ({circumflex over (ψ)}) based on the angular frequency (ω) of the electrical machine (10).
Example 3: The computer system of Example 2, wherein the processing circuitry is further configured to: obtain the maximum achievable flux linkage ({circumflex over (ψ)}) as
where UDC is the terminal voltage of the electrical machine (10).
Example 4: The computer system of any of Examples 1 to 3, wherein the processing circuitry is further configured to: obtain a maximum torque (T*max) of the electrical machine (10) based on the maximum achievable flux linkage ({circumflex over (ψ)}), and crop the reference torque (T*crop) of the electrical machine (10) based on the maximum torque (T*max).
Example 5: The computer system of any of Examples 1 to 4, wherein the processing circuitry is further configured to: obtain the first set of d and q current values (Idmax, Iqmax) as a maximum d current value and a maximum q current value.
Example 6: The computer system of any of Examples 1 to 5, wherein the processing circuitry is further configured to: obtain the second set of d and q current values (Idmin, Iqmin) as a minimum d current value and a minimum q current value.
Example 7: The computer system of Example 5 and 6, wherein the processing circuitry is further configured to: obtain a normalized current factor (k*) of the electrical machine (10) based on the normalized reference torque (T*norm).
Example 8: The computer system of Example 7, wherein the processing circuitry is further configured to: obtain a cropped normalized current factor (k*crop) based on the normalized reference torque (T*norm).
Example 9: The computer system of any of Examples 1 to 8, wherein the processing circuitry is further configured to: oscillate the d and q currents between the first and second set of current values (Idmax, Iqmax, Idmin, Iqmin) by a frequency of 10-50 Hz, preferably by a frequency of 15-25 Hz.
Example 10: The computer system of Example 1, wherein the processing circuitry is further configured to: obtain the maximum achievable flux linkage ({circumflex over (ψ)}) based on the angular frequency (ω) of the electrical machine (10), obtain the maximum achievable flux linkage ({circumflex over (ψ)}) as
where UDC is the terminal voltage of the electrical machine (10), obtain a maximum torque (T*max) of the electrical machine (10) based on the maximum achievable flux linkage ({circumflex over (ψ)}), crop the reference torque (T*crop) of the electrical machine (10) based on the maximum torque (T*max), obtain the first set of d and q current values (Idmax, Iqmax) as a maximum d current value and a maximum q current value from a current reference lookup table (242), obtain the second set of d and q current values (Idmin, Iqmin) as a minimum d current value and a minimum q current value from a current reference lookup table (242), obtain a normalized current factor (k*) of the electrical machine (10) based on the normalized reference torque (T*norm), obtain a cropped normalized current factor (k*crop) based on the normalized reference torque (T*norm), and oscillate the d and q currents between the first and second set of current values (Idmax, Iqmax, Idmin, Iqmin) by a frequency of 10-50 Hz, preferably by a frequency of 15-25 Hz, thereby producing heat in windings and/or a stator of the electrical machine (10).
Example 11: A vehicle (1) comprising the computer system of any of Examples 1-10.
Example 12: The vehicle of Example 11, further comprising: an electrical machine (10), and a heat generation system (200, 300) configured to transmit a request for increased heat generation to the computer system.
Example 13: A computer-implemented method (400), comprising: obtaining (410), by processing circuitry of a computer system, a maximum achievable flux linkage (ψ) of an electrical machine (10), obtaining (420), by the processing circuitry, a reference torque (T*crop) of the electrical machine (10) based on the maximum achievable flux linkage ({circumflex over (ψ)}), obtaining (430), by the processing circuitry, a first set of d and q current values (Idmax, Iqmax) resulting in the reference torque (T*crop), obtaining (440), by the processing circuitry, a second set of d and q current values (Idmin, Iqmin) resulting the reference torque (T*crop), and producing (450), by the processing circuitry, heat in the electrical machine (10) by oscillating the d and q currents between the first and second set of current values (Idmax, Iqmax, Idmin, Iqmin) while maintaining the reference torque (T*crop).
Example 14: The method of Example 13, further comprising: obtaining, by the processing circuitry, the maximum achievable flux linkage ({circumflex over (ψ)}) based on the angular frequency (ω) of the electrical machine (10).
Example 15: The method of Example 13 or 14, further comprising: obtaining, by the processing circuitry, a maximum torque (T*max) of the electrical machine based on the maximum achievable flux linkage (
Example 16: The method of any of Examples 13 to 15, further comprising: obtaining, by the processing circuitry, the first set of d and q current values (Idmax, Iqmax) as a maximum d current value and a maximum q current value.
Example 17: The method of any of Examples 13 to 16, further comprising: obtaining, by the processing circuitry, the second set of d and q current values (Idmin, Iqmin) as a minimum d current value and a minimum q current value.
Example 18: The method of any of Examples 13 to 17, wherein the processing circuitry is further configured to: obtain a normalized current factor (k*) of the electrical machine (10) based on the normalized reference torque (T*norm).
Example 19: A computer program product comprising program code for performing, when executed by the processing circuitry, the method of any of Examples 14 to 18.
Example 20: A non-transitory computer-readable storage medium comprising instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of any of Examples 14 to 18.
The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. 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. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof.
It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.
Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.
Number | Date | Country | Kind |
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23218111.5 | Dec 2023 | EP | regional |