A powertrain and vehicle

Abstract

This application discloses a powertrain and a vehicle. The powertrain includes a motor and a motor controller. The motor includes a first winding and a second winding, and the motor controller includes a control unit, a first drive circuit, and a second drive circuit. The control unit is used to control the first drive circuit to stop working and control the second drive circuit to work when the motor load is less than a preset load; it is also used to control both the first and second drive circuits to work when the motor load is greater than or equal to the preset load. In the first drive circuit, each phase's power device is an insulated-gate bipolar transistor (IGBT); in the second drive circuit, each phase's power device is a wide-bandgap semiconductor device. Furthermore, the current density of the first winding is greater than the current density of the second winding. This powertrain can improve the working efficiency of the motor controller and the motor, thereby increasing the driving range of the electric vehicle.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and more particularly to a powertrain and vehicle. Background Technology

[0002] In electric vehicles, the motor control unit (MCU) typically uses an IGBT (Insulated Gate Bipolar Transistor) three-phase half-bridge drive circuit to drive the motor. Since the motor is an AC motor, the function of the motor controller is to invert the DC power output from the power battery pack into AC power to supply the motor.

[0003] However, due to the significant energy losses of the IGBT devices used in the motor controller, the controller itself suffers considerable energy loss during vehicle operation. Since the battery pack of an electric vehicle has a limited capacity, excessive energy consumption by the IGBT devices reduces the efficiency of the motor controller, thus impacting the electric vehicle's driving range. Summary of the Invention

[0004] To address the above technical problems, this application provides a powertrain and vehicle that can improve the efficiency of the motor controller.

[0005] In a first aspect, this application provides a powertrain including a motor and a motor controller. The motor includes a first winding and a second winding, and the motor controller includes a control unit, a first drive circuit, and a second drive circuit. The first drive circuit is used to invert DC power output from a corresponding DC power source into AC power to supply the first winding; the second drive circuit is used to invert DC power output from a corresponding DC power source into AC power to supply the second winding. The control unit is used to control the first drive circuit to stop working and control the second drive circuit to work when the load of the motor is less than a preset load; it is also used to control both the first drive circuit and the second drive circuit to work when the load of the motor is greater than or equal to the preset load. In the first drive circuit, the power devices in each phase are of the same type, namely insulated-gate bipolar transistors (IGBTs); in the second drive circuit, the power devices in each phase are of the same type, namely wide-bandgap semiconductor devices.

[0006] When the control unit determines that the motor load is less than the preset load (i.e., light load), it controls the first drive circuit to stop working and controls the second drive circuit to work. Since the second drive circuit has lower losses, its application to the motor under light load can reduce the losses generated by the motor controller, thereby improving the efficiency of the motor controller. When the control unit determines that the motor load is greater than or equal to the preset load (i.e., heavy load), it controls both the first and second drive circuits to work, increasing the current supplied to the motor to ensure that the motor can work normally under heavy load.

[0007] Therefore, this motor controller can utilize both the high current-carrying capacity of the first drive circuit and the low loss of the second drive circuit. Current-carrying capacity characterizes the maximum current a power device can withstand during normal operation; that is, the higher the current-carrying capacity of the power device, the higher the maximum current it can withstand during normal operation. In other words, this motor controller combines the advantages of both the first and second drive circuits, improving efficiency while ensuring safety under high current conditions. When applied to electric vehicles, the motor can be the one used in the electric vehicle. Light-load scenarios correspond to situations like lightly pressing the accelerator pedal and low vehicle speed, while heavy-load scenarios correspond to situations like heavily pressing the accelerator pedal and high vehicle speed. Since the battery pack capacity of electric vehicles is limited, improving the efficiency of the motor controller can also improve the driving range of the electric vehicle.

[0008] In conjunction with the first aspect, in the first possible implementation, the current density of the first winding is greater than that of the second winding. The lower the current density of the motor windings, the lower the copper loss per unit area. Compared to a structure with equal current density distribution between the first and second windings, the structure with a lower current density in the second winding can further reduce the copper loss of the motor in its commonly used operating range, improving efficiency. Simultaneously, due to the lower current density, the aging rate of the second winding under long-term use can be reduced.

[0009] In a second possible implementation, combining the first aspect and any of the above implementations, the conductor area of ​​the first winding is larger than that of the second winding. The current density of the first winding is greater than that of the second winding, specifically manifested in the first winding having a larger slot area (i.e., conductor area) or a smaller number of conductors.

[0010] In a third possible implementation, combining the first aspect and any of the above implementations, the star point of the first winding and the star point of the second winding are connected. The star point is the neutral point of the three-phase Y-connection system, that is, the midpoint of the three-phase Y-connection. By connecting the star points of the first winding and the second winding, the functions of boost charging and auxiliary heating can be achieved.

[0011] In a fourth possible implementation, combining the first aspect and any of the above implementation methods, the star point of the first winding and the star point of the second winding are connected by a wire or a switch.

[0012] Combining the first aspect and any of the above implementation methods, in the fifth possible implementation, the motor includes a first motor and a second motor. The first motor includes a first winding, and the second motor includes a second winding. That is, the first winding and the second winding can be located in different motors. This scheme, where each of the two motors includes a set of windings, and the two sets of windings are connected at a star point, not only gives the motor and motor controller fault tolerance but also allows the motor and motor controller to adapt to different load conditions.

[0013] Combining the first aspect and any of the above implementation methods, in the sixth possible implementation method, the number of motor windings is at least a multiple of 3N, where N is an integer greater than or equal to 2. Since the power system includes at least two drive circuits, each with a three-phase half-bridge structure, the corresponding number of motor windings is at least a multiple of 3N, where N is an integer greater than or equal to 2. When one drive circuit fails, the other drive circuit can continue to operate normally, thus increasing the fault tolerance of the power system.

[0014] In combination with any of the first aspect and above implementation methods, in the seventh possible implementation method, the motor includes a six-phase winding, the first winding includes a three-phase winding of the six-phase winding, and the second winding includes the other three-phase winding of the six-phase winding.

[0015] In combination with any of the first aspect and above implementation methods, in the eighth possible implementation method, the wide bandgap semiconductor device is any one of the following: silicon carbide metal oxide semiconductor field-effect transistor (SiC-MOSFET) or gallium nitride transistor (GaN).

[0016] In a ninth possible implementation, combining the first aspect and any of the above implementations, the motor includes six-phase windings. The first drive circuit is an IGBT three-phase half-bridge drive circuit, and the second drive circuit is a SiC-MOSFET three-phase half-bridge drive circuit. The IGBT three-phase half-bridge drive circuit drives three-phase windings in the motor, and the SiC-MOSFET three-phase half-bridge drive circuit drives the other three-phase windings in the motor. When the motor is lightly loaded, the SiC-MOSFET devices have low losses, so the SiC-MOSFET three-phase half-bridge drive circuit can reduce the losses of the motor controller and improve its efficiency when operating independently. Because IGBT devices have high current handling capability, they can handle large currents, so only one IGBT device is needed for each half-bridge arm. Furthermore, when the motor is heavily loaded, the second drive circuit as a whole does not need to carry a large current, thus reducing the number of parallel SiC-MOSFET devices. This saves on device costs and reduces the number of SiC-MOSFET devices controlled by the control unit, improving control reliability.

[0017] In a tenth possible implementation, combining the first aspect and any of the above implementations, the motor includes six-phase windings. The first drive circuit is an IGBT three-phase half-bridge drive circuit, and the second drive circuit is a GaN three-phase half-bridge drive circuit. The IGBT three-phase half-bridge drive circuit drives three-phase windings in the motor, and the GaN three-phase half-bridge drive circuit drives the other three-phase windings in the motor. When the motor is lightly loaded, due to the lower losses of GaN devices, the GaN three-phase half-bridge drive circuit can reduce the losses of the motor controller and improve its efficiency by operating independently. Because IGBT devices have high current handling capacity, they can handle larger currents, requiring only one IGBT device per half-bridge arm. Furthermore, under heavy loads, the second drive circuit as a whole does not need to carry a large current, thus reducing the number of parallel GaN devices. This saves on device costs and reduces the number of GaN devices controlled by the control unit, improving control reliability.

[0018] In a possible eleventh implementation, combining the first aspect and any of the above implementations, the motor controller further includes a filter capacitor. The two ends of the filter capacitor are connected to the input terminals of the first drive circuit and the second drive circuit. The filter capacitor can be used to filter out noise from the signal.

[0019] In a twelfth possible implementation, combining the first aspect and any of the above implementations, the motor controller further includes: a first filter capacitor and a second filter capacitor. The two ends of the first filter capacitor are connected to the input terminal of the first drive circuit, and the two ends of the second filter capacitor are connected to the input terminal of the second drive circuit. The first filter capacitor and the second filter capacitor correspond to different DC power supplies.

[0020] When the first drive circuit and the second drive circuit correspond to different DC power supplies, the first filter capacitor and the second filter capacitor also correspond to different DC power supplies. Under heavy load, the current through the two drive circuits is different. Therefore, the capacitance value of the corresponding filter capacitor can be flexibly determined according to the output capability of the corresponding DC power supply, which can further reduce the current ripple on the filter capacitor.

[0021] Secondly, this application also provides a vehicle comprising the powertrain provided in any of the above implementations. The powertrain includes a motor and a motor controller. The motor includes a first winding and a second winding. The motor controller includes a control unit, a first drive circuit, and a second drive circuit. The first drive circuit inverts the DC power output from a corresponding DC power source into AC power and supplies it to the first winding. The second drive circuit inverts the DC power output from a corresponding DC power source into AC power and supplies it to the second winding. The control unit controls the first drive circuit to stop operating and controls the second drive circuit to operate when the load of the motor is less than a preset load; it also controls both the first drive circuit and the second drive circuit to operate when the load of the motor is greater than or equal to the preset load. In the first drive circuit, each phase uses the same type of power device, which is an insulated-gate bipolar transistor (IGBT); in the second drive circuit, each phase uses the same type of power device, which is a wide-bandgap semiconductor device. Furthermore, the current density of the first winding is greater than the current density of the second winding.

[0022] Because the second drive circuit has lower conduction losses, only the second drive circuit can operate under light load conditions, reducing losses generated by the driver itself and improving the energy conversion efficiency of the motor controller. When the control unit determines that the motor load is greater than or equal to the preset load (i.e., heavy load), it controls both the first and second drive circuits to operate. This utilizes the higher current-carrying capacity of the first drive circuit and the lower losses of the second drive circuit, combining the advantages of both circuits to improve efficiency while ensuring safety under high current conditions.

[0023] Furthermore, based on the first and second drive circuits, this application also provides a solution where the current densities of the first and second windings of the motor are unequal when current flows, with the current density of the first winding being greater than that of the second winding. The lower the current density of the motor windings, the lower the copper loss per unit area. When the vehicle's motor is under light load, the control unit controls the second drive circuit to drive the motor. Simultaneously, because the current density of the second winding is lower (compared to a structure with equal current density distribution between the first and second windings), copper loss under light load conditions, such as in commonly used operating areas, can be further reduced, improving efficiency and slowing down the aging rate of the second winding under long-term use.

[0024] When the motor needs to output a large torque, such as when the motor reaches its peak torque, the motor load is greater than or equal to the preset load. The control unit controls the first drive circuit to supply power to the first winding, and simultaneously controls the second drive circuit to supply power to the second winding. Because the current density of the first winding is larger (compared to a structure where the first and second windings have equal current density distribution), the temperature rise is higher. However, this operating condition only occurs for a short time and is not used for a long period of time. Therefore, the winding distribution scheme proposed in this embodiment can maximize the utilization of the current density of the first and second windings.

[0025] In summary, the vehicle provided by the embodiments of this application can improve the working efficiency of the motor controller and the motor, thereby increasing the driving range of the electric vehicle. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an IGBT three-phase half-bridge drive circuit.

[0027] Figure 2 A schematic diagram of a powertrain provided in an embodiment of this application;

[0028] Figure 3 A schematic diagram of another powertrain provided in an embodiment of this application;

[0029] Figure 4 A schematic diagram of the driving signals provided in the embodiments of this application;

[0030] Figure 5 A schematic diagram of yet another powertrain provided in an embodiment of this application;

[0031] Figure 6 A schematic diagram of yet another powertrain provided in an embodiment of this application;

[0032] Figures 7A to 7B A circuit diagram of a powertrain provided in an embodiment of this application;

[0033] Figures 8A to 8B Another circuit diagram of the powertrain provided in the embodiments of this application;

[0034] Figure 9 A circuit diagram of powertrain auxiliary heating provided in an embodiment of this application; Detailed Implementation

[0035] To facilitate a better understanding of the technical solutions provided in this application by those skilled in the art, the following description uses a motor and motor controller in an electric vehicle as an example. The embodiments of this application do not limit the specific application scenarios of the motor and motor controller.

[0036] In electric vehicles, the powertrain includes the motor and the motor controller. The motor controller's function is to obtain electrical energy from the battery pack, convert it into the current and voltage required by the motor, and then use the motor to provide power to the load. Therefore, the conversion efficiency of the motor controller affects the efficiency of the battery pack and thus the driving range of the electric vehicle.

[0037] First, we will introduce the working principle of an electric vehicle motor using an IGBT three-phase half-bridge drive circuit.

[0038] See Figure 1 The figure shows a schematic diagram of a motor using an IGBT three-phase half-bridge drive circuit.

[0039] Among them, motor 10 is a three-phase motor, and the motor controller includes IGBT three-phase half-bridge drive circuit 20, with filter capacitors connected in parallel across the two ends of IGBT three-phase half-bridge drive circuit 20.

[0040] IGBT devices have significant losses, leading to substantial energy loss in the motor controller itself. This reduces the conversion efficiency of the battery pack in electric vehicles, especially under light motor loads. For example, under light motor loads, the accelerator pedal is lightly pressed, resulting in a lower vehicle speed. At this time, the motor's output power is also lower, and the switching losses of the IGBT devices account for a large proportion of the total losses.

[0041] To address the above technical problems, this application provides a powertrain including a motor and a motor controller composed of hybrid power devices. The motor includes a first winding and a second winding, and the motor controller includes at least two drive circuits, including a first drive circuit and a second drive circuit. This improves the efficiency of the motor controller, thereby increasing the driving range of the electric vehicle's power battery pack.

[0042] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings. It is understood that the terms "first" and "second" in the following embodiments are for ease of explanation only and do not constitute a limitation of the present application.

[0043] This application provides a powertrain, and the following description will take the application of the powertrain in an electric vehicle scenario as an example.

[0044] See Figure 2 The figure is a schematic diagram of a powertrain provided in an embodiment of this application.

[0045] The powertrain includes a motor controller and a motor. The motor controller includes a control unit 203 and at least two drive circuits: a first drive circuit 201 and a second drive circuit 202. The motor includes a first winding 101 and a second winding 102.

[0046] The first drive circuit 201 inverts the DC power output from the corresponding DC power supply into AC power and supplies it to the first winding 101 of the motor.

[0047] The second drive circuit 202 inverts the DC power output from the corresponding DC power supply into AC power and supplies it to the second winding 102 of the motor.

[0048] It should be noted that the first driving circuit 201 and the second driving circuit 202 can correspond to the same DC power supply or different DC power supplies. For example, the first driving circuit 201 corresponds to DC power supply A and the second driving circuit 201 corresponds to DC power supply B.

[0049] In practical applications, when the application scenario is an electric vehicle, the DC power source can be the electric vehicle's battery pack. When the first drive circuit 201 and the second drive circuit 202 correspond to the same DC power source, the electric vehicle includes one battery pack. When the first drive circuit 201 and the second drive circuit 202 correspond to two different DC power sources, the electric vehicle can include two battery packs.

[0050] The types of power devices in the first drive circuit 201 of this motor controller are different from those in the second drive circuit 202. Specifically, the power device losses in the first drive circuit 201 are greater than those in the second drive circuit 202, and the current-carrying capacity of the power device in the first drive circuit 201 is also greater than that in the second drive circuit 202. This current-carrying capacity characterizes the power device's ability to allow the maximum current to flow through it.

[0051] When the control unit 203 determines that the motor load is less than the preset load, i.e., when the motor is in a light-load state, it controls the first drive circuit 201 to stop working and controls the second drive circuit 202 to work. The second drive circuit 202 has a lower current-carrying capacity but also lower losses. When the motor is under light load, it can reduce the losses generated by the motor controller, thereby improving the efficiency of the motor controller. The above light-load motor scenario corresponds to the common operating conditions of electric vehicles in actual applications, such as NEDC (New European Driving Cycle) and WLTC (World Light Vehicle Test Procedure), such as lightly pressing the accelerator pedal and low vehicle speed.

[0052] When the control unit 203 determines that the motor load is greater than or equal to the preset load, it controls both the first drive circuit 201 and the second drive circuit 202 to operate. This utilizes both the higher current-carrying capacity of the first drive circuit and the lower loss of the second drive circuit, thus combining the advantages of both circuits to improve efficiency while ensuring safety under high current conditions. The above-described heavy-load motor scenario corresponds to situations in practical applications where the motor reaches its peak torque, such as when the accelerator pedal is pressed hard or the vehicle speed is high.

[0053] The preset load can be determined according to the actual situation. This application embodiment does not make specific limitations on this. The control unit can obtain the current load status of the motor through the vehicle controller of the electric vehicle.

[0054] In summary, by utilizing the powertrain provided in this application, the operating state of the drive circuit can be determined based on the magnitude of the motor load, thereby improving the efficiency of the motor controller. For example, when the motor is used in an electric vehicle, this can further enhance the driving range of the electric vehicle's onboard battery (power battery pack).

[0055] The motor controller will be explained below with reference to specific types of power devices.

[0056] For example, the power device of the first driving circuit 201 is an IGBT (Insulated Gate Bipolar Transistor), and the power device of the second driving circuit is a wide bandgap semiconductor device. Specifically, the wide bandgap semiconductor device can be a SiC-MOSFET (Silicon Carbide Metal Oxide Semiconductor) or a gallium nitride (GaN) transistor.

[0057] Taking an example where the power device in the first drive circuit is an IGBT and the power device in the second drive circuit is a SiC-MOSFET, this explanation is provided. When this motor driver is applied to an electric vehicle, the first drive circuit can be an IGBT three-phase half-bridge drive circuit, and the second drive circuit can be a SiC-MOSFET three-phase half-bridge drive circuit. Taking a motor winding consisting of six phases as an example, specifically including two three-phase windings, the IGBT three-phase half-bridge drive circuit is used to drive the three-phase windings in the motor, and the SiC-MOSFET three-phase half-bridge drive circuit is used to drive the other three phase windings in the motor.

[0058] Specifically, the first drive circuit 201 is an IGBT three-phase half-bridge drive circuit. The first drive circuit 201 is connected to the first winding 101 of the motor, namely the three-phase windings U, V, and W in the figure.

[0059] When using IGBT devices, the number of devices can be reduced due to their high current handling capability; that is, each bridge arm includes one IGBT device in both the upper and lower halves.

[0060] The second drive circuit 202 is specifically a SiC-MOSFET three-phase half-bridge drive circuit. The second drive circuit 202 is connected to the second winding 102 of the motor, namely the three-phase windings X, Y, and Z in the figure.

[0061] Because the current-carrying capacity of SiC-MOSFET devices is lower than that of IGBT devices, in practical operation, multiple SiC-MOSFET devices need to be connected in parallel to be equivalent to a single power device when handling the same current. This means that each SiC-MOSFET device shunts the overall current. Specifically, the upper and lower halves of each bridge arm (202a) actually include multiple parallel SiC-MOSFET devices; the figure only shows these multiple parallel SiC-MOSFET devices as equivalent to a single SiC-MOSFET device. However, IGBT devices have a higher current-carrying capacity and can handle larger currents, so only one IGBT device is needed for each half-bridge arm.

[0062] The number of SiC-MOSFET devices connected in parallel can be determined according to the actual situation, for example, by combining the specific setting value of the preset load. This application embodiment does not make specific limitations here.

[0063] Since the motor controller includes at least two drive circuits, and the motor correspondingly includes at least two windings, in practical applications, when both the first drive circuit 201 and the second drive circuit 202 are three-phase half-bridge drive circuits, the motor windings will include at least six-phase windings. For example, the motor 101 includes at least two three-phase windings—a first winding 101 and a second winding 102. The first drive circuit 201 drives the first winding 101, and the second drive circuit 202 drives the second winding 102.

[0064] It should be noted that, in this embodiment based on the first drive circuit 102 and the second drive circuit 202, the current densities of the first winding 101 and the second winding 102 of the motor are not equal when current flows through them, and the current density of the first winding 101 is greater than that of the second winding 102. Specifically, the smaller current density is manifested by the corresponding winding having a larger slot area (i.e., conductor area) or a smaller number of conductors, etc.

[0065] The lower the current density of the motor windings, the lower the copper loss per unit area. Taking electric vehicles as an example, under normal operating conditions (NEDC / WLTC, etc.), the motor load is less than the preset load, and the motor current only needs to reach less than 1 / 2 of the peak current. At this time, the control unit 203 controls the second drive circuit 202 to drive the motor. At the same time, since the current density of the second winding 102 is smaller (compared to the structure of equal current density distribution between the first and second windings), the copper loss in the normal operating condition area can be further reduced, efficiency can be improved, and the aging rate of the second winding 102 under long-term use can be reduced.

[0066] When the motor needs to output a large torque, for example when the motor reaches its peak torque, and the motor load is greater than or equal to the preset load, the control unit 203 controls the first drive circuit 201 to supply power to the first winding 101, and simultaneously controls the second drive circuit 202 to supply power to the second winding 102. Because the current density of the first winding 101 is larger (compared to a structure where the first and second windings have equal current density distribution), the temperature rise is higher. However, this operating condition only occurs for a short time and will not be used for a long time. Therefore, the winding distribution scheme proposed in this embodiment can maximize the utilization of the current density of the first and second windings.

[0067] The motor driver also includes a filter capacitor C1.

[0068] The filter capacitor C1 is connected between the input terminals of the first driving circuit 201 and the second driving circuit 202. The filter capacitor C1 can be used to filter out noise in the signal.

[0069] In this embodiment, the first driving circuit 201 and the second driving circuit 202 are not simply superimposed. The first driving circuit 201 and the second driving circuit 202 need to be controlled by the control unit 203 to drive the motor 101. The working principle of the control unit 203 is explained in detail below.

[0070] See Figure 3 , Figure 3 A schematic diagram of another powertrain provided in an embodiment of this application;

[0071] The control unit 203 generates drive signals for the first drive circuit 201 and the second drive circuit 202. Specifically, the first set of drive signals corresponds to the first drive circuit 201, and the second set of drive signals corresponds to the second drive circuit 202. The first set of drive signals, after being amplified by the first drive chip 204a, is used to control the operating state of the power devices in the first drive circuit 201. The second set of drive signals, after being amplified by the second drive chip 204b, is used to control the operating state of the power devices in the second drive circuit 202. Both drive chips have signal amplification functions. The two drive chips can be set independently or integrated together; this embodiment does not specifically limit this.

[0072] See Figure 4 This figure is a schematic diagram of the driving signals provided in an embodiment of this application.

[0073] The VCU (Vehicle Control Unit) of an electric vehicle can send the current load of the motor to the control unit 203 of the drive. When the current load of the motor is lower than the preset load, the second control unit 203b stops sending the second set of drive signals to the power devices of the second drive circuit 202, so that the second drive circuit 202 stops working. At this time, only the first drive circuit 201, i.e. the SiC-MOSFET device, works, which can reduce the losses generated by the motor controller and thus improve the efficiency of the motor controller.

[0074] When the motor load exceeds the preset load (i.e., heavy load), the first control unit 203a and the second control unit 203b simultaneously send drive signals. The phase difference φ between the first and second sets of drive signals ranges from 0 to 180°. That is, the control circuit interleaves the signals from the two drive circuits, compared to... Figure 1 The solution shown can reduce the ripple current of the filter capacitor C1, thus reducing the capacitance requirement of the filter capacitor C1, lowering the component cost, and making the motor torque ripple smoother and with lower NVH (Noise, Vibration, Harshness, a comprehensive indicator for measuring the quality of automobile manufacturing).

[0075] The phase difference between the first set of driving signals and the second set of driving signals is in the range of 0-180 degrees. The phase difference between the first set of driving signals and the second set of driving signals can be set according to actual needs, and no specific limitation is made in this embodiment.

[0076] When the motor is under heavy load, the two power devices work together, taking advantage of the high current withstand capability of the first drive circuit and the low loss of the second drive circuit. This combines the advantages of both the first and second drive circuits, improving working efficiency and ensuring safety under high current. Furthermore, the second drive circuit as a whole does not need to carry a large current, thus reducing the number of parallel SiC-MOSFET devices. This saves on device costs and reduces the number of SiC-MOSFET devices controlled by the control unit, thereby improving control reliability.

[0077] In summary, the motor controller provided in this application allows for the determination of the operating state of the drive circuit based on the magnitude of the motor load, thereby improving the efficiency of the motor controller and extending the driving range of the electric vehicle's on-board battery (power battery pack). Furthermore, since the motor controller includes at least two drive circuits, when one drive circuit fails, the controller can control the other drive circuit to continue operating normally, thus increasing the fault tolerance of the motor controller.

[0078] See Figure 5 This figure is a schematic diagram of another powertrain provided in an embodiment of this application;

[0079] The motor controller provided in this embodiment and Figure 2 The difference in the powertrain shown is that the powertrain may specifically include the following two filter capacitors: a first filter capacitor C1 and a second filter capacitor C2, that is, each drive circuit corresponds to one filter capacitor.

[0080] As shown in the figure, the first filter capacitor C1 is connected to the input terminal of the first driving circuit 201. The second filter capacitor C2 is connected to the input terminal of the second driving circuit 202.

[0081] When the first drive circuit 201 and the second drive circuit 202 correspond to different DC power supplies, the first filter capacitor C1 and the second filter capacitor C2 also correspond to different DC power supplies. Under heavy load, the current through the two drive circuits is different. Therefore, the capacitance value of the corresponding filter capacitor can be flexibly determined according to the output capability of the corresponding DC power supply, which can further reduce the current ripple on the filter capacitor.

[0082] In another implementation of this application, when the motor windings include six-phase windings, the first drive circuit is an IGBT three-phase half-bridge drive circuit for driving the three-phase windings of the motor, and the second drive circuit is a GaN three-phase half-bridge drive circuit for driving the other three-phase windings of the motor. The working principles of GaN devices and SiC-MOSFET devices are similar. In this case, the control unit of the motor controller can use a control method similar to that described above to control the operating state of the two drive circuits, which will not be repeated here.

[0083] Based on the above embodiments, the first winding and the second winding may also have a structure for leading out star points, which is used to connect the star points of the first winding and the star points of the second winding.

[0084] See Figure 6 This figure is a schematic diagram of another powertrain provided in an embodiment of this application.

[0085] Specifically, the first drive circuit 201 is an IGBT three-phase half-bridge drive circuit. The first drive circuit 201 is connected to the first winding of the motor 101, namely the three-phase windings U, V, and W in the figure.

[0086] When using IGBT devices, the number of devices can be reduced due to their high current handling capability; that is, each bridge arm includes one IGBT device in both the upper and lower halves.

[0087] The second drive circuit 202 is specifically a SiC-MOSFET three-phase half-bridge drive circuit. The second drive circuit 202 is connected to the second winding of the motor 101, namely the three-phase windings X, Y, and Z in the figure. Embodiment 2, regarding the implementation method of a powertrain including a motor and a motor controller composed of hybrid power devices to improve efficiency while considering cost, is the same as the powertrain embodiment described above, and will not be repeated here.

[0088] It should be noted that the star point of the first winding 101 and the star point of the second winding 102 are connected by a wire or by a switch, which can be a relay. The star point is the neutral point of the three-phase Y-connection system, that is, the midpoint of the three-phase Y-connection.

[0089] By connecting the star point of the first winding 101 and the star point of the second winding 102, boost charging and auxiliary heating functions can be achieved. See [link / reference] Figure 7A and Figure 7B , Figures 7A to 7B This is a circuit diagram of a powertrain provided in an embodiment of this application. For ease of explanation, only the inductor charging and discharging current on one side of the IGBT module is shown in the figure. Figure 7A In this circuit, the positive terminal of the charging power supply is connected to the positive terminal of the powertrain bus voltage (BUS+), and the negative terminal of the charging power supply is connected to the star point of the first winding 101 and the star point of the second winding 102. When the inductor is charging, the three-phase bridge arm connected to the BUS+ side is turned on, and the three-phase bridge arm connected to the negative terminal of the bus voltage (BUS-) side is turned off. At this time, the first winding 11 is in the energy storage stage. Figure 7BIn the process, when the first winding 101 is connected in series with the charging power supply to discharge to the power battery, the three-phase bridge arm connected to the BUS+ side is turned off, and the three-phase bridge arm connected to the BUS- side is turned on. At this time, the current in the first winding 101 continues through the three-phase bridge arm connected to the BUS- side.

[0090] See Figure 8A and Figure 8B , Figures 8A to 8B This is another circuit diagram of the powertrain boost charging provided in the embodiment of this application. For ease of explanation, only the inductor charging and discharging current on the IGBT module side is shown in the figure. Figure 8A In this circuit, the negative terminal of the charging power supply is connected to the negative terminal of the powertrain bus voltage (BUS-), and the positive terminal of the charging power supply is connected to the star point of the first winding 101 and the star point of the second winding 102. When the inductor is charging, the three-phase bridge arm connected to the BUS- side is turned on, and the three-phase bridge arm connected to the positive terminal of the bus voltage (BUS+) side is turned off. At this time, the first winding 201 is in the energy storage stage. Figure 8B In the process, when the first winding 201 is connected in series with the charging power supply to discharge to the power battery, the three-phase bridge arm connected to the BUS- side is turned off, and the three-phase bridge arm connected to the BUS+ side is turned on. At this time, the current in the first winding 201 continues through the three-phase bridge arm connected to the BUS+ side.

[0091] For ease of explanation, Figures 7A to 7B , Figures 8A to 8B All examples demonstrate the use of only the first driving circuit, i.e., the IGBT module, for boost charging. Since the second driving circuit SiC module is connected in parallel with the first driving circuit IGBT module, it is possible to choose to use only the IGBT module, only the SiC module, or both modules simultaneously for boost charging, based on the same working principle described above.

[0092] See Figure 9 , Figure 9 This is a circuit diagram illustrating auxiliary heating for a powertrain according to an embodiment of this application. Taking an electric vehicle as an example, since the star point of the first winding 201 and the star point of the second winding 202 are connected, the motor can be heated using zero-sequence current (current components with the same three-phase current waveform that do not generate torque), and the generated heat can be transferred to other vehicle locations requiring heating, such as the battery or passenger compartment, through a motor heat collection system. The motor heat collection system can be constructed by connecting the powertrain cooling water circuit to the cooling water circuit of the battery or passenger compartment.

[0093] Based on the above powertrain embodiment, the motor may include two motors: a first motor and a second motor. The first motor includes a first winding, and the second motor includes a second winding. That is, the first winding and the second winding can be located in different motors. By adopting a scheme in which each of the two motors includes a set of windings and the two sets of windings are connected in a star-point configuration, both boost charging and parking auxiliary heating functions can be achieved. For details, please refer to the above powertrain embodiment, which will not be repeated here.

[0094] The above embodiment uses a motor winding comprising six phases, with the first drive circuit and the second drive circuit each driving three phases as an example. In practical applications, the number of phases in the motor windings can be increased according to load requirements. For example, motors with nine, twelve, or fifteen phases can also be used. In this case, multiple first drive circuits or multiple second drive circuits may be included, and a third drive circuit may be included that uses different power devices than the first and second drive circuits. It should be noted that the number of phases in the motor windings must be a multiple of three.

[0095] In practical applications, the implementation methods of the various motor controllers and motors mentioned above can be determined by comprehensively considering factors such as the specific type of electric vehicle (car, bus, truck, etc.), motor load conditions (light load, heavy load) and component costs. This application does not impose specific limitations on these aspects.

[0096] By increasing the number of motors, the number of phases, and the number of drive circuits, not only are the motors and motor controllers made fault-tolerant, but they can also adapt to different load conditions. Furthermore, when the number of motor phases is fixed, by adjusting the types of power devices used in each drive circuit, an optimal (or near-optimal) balance can be achieved between motor efficiency, motor stability, and device cost.

[0097] Based on the powertrain provided in the above embodiments, this application also provides a vehicle including the powertrain provided in the above embodiments. The vehicle includes the powertrain, wherein the powertrain specifically includes a motor and a motor controller. The motor includes a first winding and a second winding, and the motor controller includes a control unit, a first drive circuit, and a second drive circuit.

[0098] The vehicle provided in this application includes the powertrain described in any of the above embodiments. The motor drive includes at least two different drive circuits: a first drive circuit and a second drive circuit. The types of power devices in the first drive circuit are different from those in the second drive circuit. The power device losses in the first drive circuit are greater than those in the second drive circuit, and the current-carrying capacity of the power devices in the first drive circuit is also greater than that in the second drive circuit. When the control unit of the motor controller determines that the motor load is less than a preset load (i.e., light load), it controls the first drive circuit to stop working and controls the second drive circuit to work. Because the second drive circuit has lower conduction losses, only the second drive circuit works under light load, which reduces the losses generated by the driver and improves the driver efficiency. When the control unit determines that the motor load is greater than or equal to the preset load (i.e., heavy load), it controls both the first and second drive circuits to work. This utilizes the higher current-carrying capacity of the first drive circuit and the lower losses of the second drive circuit, combining the advantages of both circuits to improve efficiency and ensure safety under high current conditions.

[0099] An electric motor is used to provide power to a load. The first and second windings of the motor have different current densities when current flows through them, with the first winding having a higher current density than the second. Specifically, a smaller current density manifests as the corresponding winding having a larger slot area (i.e., conductor area) or fewer conductors.

[0100] It should be noted that the star point of the first winding and the star point of the second winding may not be connected, or they may be connected by a single wire or by a switch, wherein the switch may be a relay.

[0101] The number of windings in the motor is at least a multiple of 3, where N is an integer greater than or equal to 2. For example, the motor windings can be any of the following: six-phase windings, nine-phase windings, twelve-phase windings, fifteen-phase windings, and more. The first and second windings can also be located in different motors.

[0102] In summary, the power system provided in this application, when applied to electric vehicles, can improve the efficiency of the motor controller, thereby increasing the driving range of the electric vehicle's on-board battery (power battery pack). Furthermore, since the power system includes at least two drive circuits, if one drive circuit fails, the other drive circuit can continue to operate normally, thus increasing the fault tolerance of the power system.

[0103] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0104] The above description is merely a preferred embodiment of this application and is not intended to limit the application in any way. Although this application has disclosed preferred embodiments above, it is not intended to limit the application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A powertrain, characterized in that, The device includes a motor and a motor controller. The motor includes a first winding and a second winding, and the motor controller includes a first drive circuit and a second drive circuit. The positive terminal of the powertrain bus voltage is connected to the positive terminal of the power battery, and the negative terminal of the powertrain bus voltage is connected to the negative terminal of the power battery. The positive terminal of the powertrain bus voltage is connected to one side of the first drive circuit and one side of the second drive circuit, respectively, and the negative terminal of the powertrain bus voltage is connected to the other side of the first drive circuit and the other side of the second drive circuit, respectively. The star point of the first winding and the star point of the second winding are connected by a wire or a switch; The positive terminal of the charging power supply is connected to the positive terminal of the bus voltage of the powertrain, and the negative terminal of the charging power supply is connected to the star point of the first winding and the star point of the second winding. At least one of the first drive circuit and the second drive circuit is used to charge the power battery, wherein: One side of the bridge arm of the first drive circuit is turned on, then the other side of the bridge arm of the first drive circuit is turned off, and the first winding is connected in series with the charging power supply to charge the power battery. One side of the bridge arm of the second drive circuit is turned on, then the other side of the bridge arm of the second drive circuit is turned off, and the second winding is connected in series with the charging power supply to charge the power battery. Alternatively, the positive terminal of the charging power supply is connected to the star point of the first winding and the star point of the second winding, and the negative terminal of the charging power supply is connected to the negative terminal of the bus voltage of the powertrain. At least one of the first drive circuit and the second drive circuit is used to charge the power battery, wherein: The other side of the first drive circuit is turned on, then the other side of the first drive circuit is turned off, and the first side of the first drive circuit is turned on. The first winding is connected in series with the charging power supply to charge the power battery. The other side of the second drive circuit is turned on, then the other side of the second drive circuit is turned off, and the first side of the second drive circuit is turned on. The second winding is connected in series with the charging power supply to charge the power battery.

2. The powertrain according to claim 1, characterized in that, The current density of the first winding is greater than the current density of the second winding.

3. The powertrain according to claim 1 or 2, characterized in that, The conductor area of ​​the first winding is larger than that of the second winding.

4. The powertrain according to any one of claims 1-3, characterized in that, The motor includes a first motor and a second motor, the first motor including a first winding and the second motor including a second winding.

5. The powertrain according to any one of claims 1-4, characterized in that, The number of winding phases of the motor is N times 3, where N is an integer greater than or equal to 2.

6. The powertrain according to any one of claims 1-5, characterized in that, The motor includes a six-phase winding, the first winding includes three phase windings of the six-phase winding, and the second winding includes the other three phase windings of the six-phase winding.

7. The powertrain according to any one of claims 1-6, characterized in that, In the second driving circuit, the power device for each phase is a wide bandgap semiconductor device, which is any one of the following: silicon carbide metal oxide semiconductor field-effect transistor (SiC-MOSFET) or gallium nitride transistor (GaN).

8. The powertrain according to any one of claims 1-7, characterized in that, It also includes: filter capacitors; The two ends of the filter capacitor are respectively connected to the input terminals of the first driving circuit and the second driving circuit.

9. The powertrain according to any one of claims 1-8, characterized in that, Also includes: First filter capacitor and second filter capacitor; The first filter capacitor is connected to the input terminal of the first driving circuit; The second filter capacitor is connected to the input terminal of the second driving circuit.

10. A vehicle, characterized in that, The vehicle includes a powertrain and a power battery as described in any one of claims 1-9, wherein the power battery is used to output direct current to the motor controller.

11. The vehicle according to claim 10, characterized in that, It also includes a vehicle controller, which sends the load of the motor to the control unit of the motor controller.

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