MOTOR CONTROL UNIT, POWERTRAIN, CONTROL METHOD, AND ELECTRIC VEHICLE

Abstract

This application discloses a motor control unit, a power train, a control method, and an electric vehicle, and relates to the field of electric vehicle technology. The input end of the motor control unit is connected to a power battery pack, and the output end of the motor control unit is connected to three phases of a motor winding of a motor, and the motor control unit includes an inverter circuit and a controller. The input end of the inverter circuit is an input end of the motor control unit, and each phase of the output end of the inverter circuit is connected to one phase of a motor winding of the motor. The controller controls the inverter circuit to output current to the three phases of the motor winding simultaneously, and controls the current input to all phases of the motor winding to reach a preset current in sequence. According to the motor control unit, the heat generating capacity of the motor winding is fully used to heat the power battery pack, the symmetry and reliability of the motor are ensured, and the case where an additional heating device is used to heat the power battery pack can be avoided, and the occupied space and cost are reduced.

Description

[Technical field]

[0001] The present application relates to the field of electric vehicle technology, in particular to a motor control unit, a powertrain, a control method and an electric vehicle. [Background technology]

[0002] In the modern society, energy shortage and environmental pollution are becoming serious, so new energy vehicles and electric vehicles have been widely paid attention. An electric vehicle is powered by a power battery pack and uses a motor to convert electrical energy into mechanical energy to drive the motor.

[0003] Due to the large number of electric vehicles deployed, many electric vehicles are used in cold regions in winter and in regions where it is always cold. However, the power battery pack of an electric vehicle has relatively poor discharge performance at low temperatures, so the power battery needs an efficient low-temperature heating measure to ensure that the power battery pack can output power to the motor within a safe temperature range.

[0004] FIG. 1 is a schematic diagram of a heating device for a power battery pack in the prior art.

[0005] The heating device includes a positive temperature coefficient (PTC) resistor Rp and a controllable switching transistor S. The PTC resistors Rp and S are connected in series, and then connected in parallel with a bus capacitor Co of the electric vehicle. When a Battery Management System (BMS) of the electric vehicle determines that the battery temperature is relatively low, the controllable switching transistor S is controlled to be closed, and the PTC resistor Rp is connected in the circuit, which then releases heat and heats the power battery pack. However, this heating method requires an additional heating device to be added, which occupies space and increases costs.

[0006] Another method of heating the power battery pack in the prior art is as follows: waste heat generated from the motor winding is absorbed using a heat conducting medium and used to heat the power battery pack. However, this method solution has two problems: first, the heat generated only from the motor winding is utilized, and the heating power is relatively small and the heating speed is relatively low. Second, in this method, the three phases of the motor winding are utilized as a current loop, and the current is injected into the motor winding in the following manner: current is input into one phase of the winding, and the other two phases of the winding output current; or current is input into one phase of the winding, one phase of the winding outputs current, and the current of the third phase of the winding is zero. However, regardless of the method used, the currents of the three phases of the winding cannot be equal, and therefore the three phases of the winding generate heat unevenly. Due to the uneven heat generation, the phase of the winding that generates relatively high heat will age relatively quickly, which is likely to cause problems such as three-phase imbalance, thus affecting the performance of the motor. Also, due to uneven heat generation, the winding temperature rise is limited by the hottest winding phase. This through-current heating method does not fully utilize the heat generation capability of the three phases of the winding. Summary of the Invention

[0007] The present application provides a motor control unit, a powertrain, a control method, and an electric vehicle to avoid the need for an additional heating device to be added to heat the power battery pack, reduce the occupied space and cost, and improve the heating effect of the power battery pack.

[0008] According to a first aspect, the present invention provides a motor control unit (MCU). An input end of the motor control unit is connected to a power battery pack, and an output end of the motor control unit is connected to three phases of a motor winding of a motor. The motor control unit includes an inverter circuit and a controller. An input end of the inverter circuit is an input end of the motor control unit, and each phase of the output end of the inverter circuit is connected to one phase of a motor winding of the motor. The controller: controls the inverter circuit to output currents to the three phases of the motor winding simultaneously, and controls the currents input to all the phases of the motor winding to reach a preset current sequentially.

[0009] The controller controls the inverter circuit to output current to the three phases of the motor winding simultaneously. In this case, all three phases of the motor winding generate heat, so that the overall heating output of the motor increases. The controller also controls the output current of the inverter circuit so that all currents of the phases of the motor winding reach the preset current in sequence. When the current of the motor winding is the preset current, the motor winding has a relatively high heating output, so that the three phases of the motor winding generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This makes full use of the heat generation capacity of the motor winding, improves the heating speed of the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened because the motor winding generates heat for a long time, thus further improving the symmetry and reliability of the motor. The solution provided in this application also avoids the case where an additional heating device is added to heat the power battery pack, reducing the occupied space and cost.

[0010] The controller is an application-specific integrated circuit. t、The PLD may be an ASIC, a Programmable Logic Device (PLD), a Digital Signal Processor (DSP), or a combination thereof. The PLD may be a Complex Programmable Logic Device (CPLD), a Field-programmable Gate Array (FPGA), a Generic Array Logic (GAL), or any combination thereof. This is not particularly limited in this application.

[0011] The inverter circuit includes a controllable switching transistor. The type of the controllable switching transistor is not particularly limited in this application. For example, the controllable switching transistor can be an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), or a silicon carbide metal oxide semiconductor (SiC MOSFET).

[0012] The controller sends a control signal to the controllable switching transistor to control the operating state of the controllable switching transistor. The control signal may be a Pulse Width Modulation (PWM) signal.

[0013] In a possible implementation, the controller further determines the preset current based on a temperature of the power battery pack, the magnitude of the preset current being negatively correlated with the temperature of the power battery pack.

[0014] For the power battery pack, within the same heating time, it indicates that the lower the temperature of the power battery pack, the higher the rate at which the power battery pack is needed to heat up, and the corresponding larger magnitude of the preset current is needed.

[0015] The controller may obtain temperature information of the power battery pack using a Vehicle Control Unit (VCU) or BMS to determine the temperature of the power battery pack.

[0016] In a possible implementation, the controller further determines a preset current based on the obtained heating command, and the heating command is used to indicate the magnitude of the preset current. The driver may determine the heating output level of the power battery pack (a higher heating output level indicates a higher heating speed) or adjust the heating time of the power battery pack (a shorter heating time corresponds to a higher heating output level) based on the actual requirements. The Vehicle Control Unit (VCU) may: driver In response to the input operation performed by the controller, the controller refers to the current temperature information of the power battery pack to determine a corresponding heating command, and sends the heating command to the controller. The heating command is used to indicate the magnitude of the preset current.

[0017] In a possible implementation, the controller is configured, inter alia, to: determine an amplitude and a phase of an input current for each phase of the motor winding based on a preset position angle and a preset current, where the preset position angle represents the angle between the preset current and a d-axis of the motor; determine an amplitude and a phase of an input voltage for each phase of the motor winding based on the amplitude and phase of the input current for each phase of the motor winding and the impedance of each phase of the motor winding; determine a duty cycle of a control signal for the inverter circuit based on the amplitude of the input voltage, and determine a transmission time of the control signal for the inverter circuit based on the phase of the input voltage, so as to control the motor control unit using the corresponding control signal.

[0018] In a possible implementation, the controller is particularly configured to control the preset position angle to vary periodically within the preset angle range such that the current input to all phases of the motor windings sequentially reaches the preset current.

[0019] In a possible embodiment, the preset angle range is from 0° to 360°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive divisor of 120.

[0020] Positive divisors of 120 include 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, and 120.

[0021] In a possible implementation, the preset angle range is from 0° to 120°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive submultiple of 60.

[0022] Positive divisors of 60 include 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

[0023] In a possible implementation, the controller is specifically configured to control the current output by the inverter circuit to each of the three phases of the motor winding to have one of the following waveforms: sine wave, square wave, or triangular wave.

[0024] In a possible implementation, the inverter circuit is a three-phase two-level inverter circuit or a three-phase three-level inverter circuit.

[0025] In a possible implementation, the controller is further configured to control an operating state of the pump device, wherein the motor performs heat exchange using the first cooling loop and uses the pump device to drive a cooling medium circulating within the first cooling loop.

[0026] According to a second aspect, the present application provides a powertrain. The powertrain includes a motor control unit provided in the above implementation, and further includes a motor, a first cooling loop, a second cooling loop, a pump device, and a heat exchanger. The first cooling loop is configured to perform heat exchange for the motor. The second cooling loop is configured to perform heat exchange between the motor control unit and a power battery pack. The pump device is configured to drive a cooling medium to circulate in the first cooling loop. The heat exchanger is configured to perform heat exchange between the cooling medium in the first cooling loop and the cooling medium in the second cooling loop.

[0027] The first and second cooling loops of the powertrain sufficiently absorb the heat generated from the motor control unit and the motor windings and heats up the power battery pack, thus increasing the rate at which the power battery pack heats up.

[0028] According to a third aspect, the present application further provides a control method for a motor control unit, the control method being used to control the motor control unit provided in the above-mentioned implementation. The method includes the following steps: determining a preset current to be used by all phases of the motor winding to heat the power battery pack; controlling the inverter circuit to simultaneously output current to three phases of the motor windings; and controlling the current input to all of the phases of the motor windings to sequentially reach a preset current.

[0029] According to this control method, all three phases of the motor winding can be controlled to generate heat, and thus the heat output of the entire motor is increased. Also, the output current of the inverter circuit is controlled so that the current of all phases of the motor winding reaches the preset current in sequence. When the current of the motor winding is the preset current, the motor winding has a relatively high heating output, and thus the three phases of the motor winding generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This allows the heating capacity of the motor winding to be fully used, the speed of heating the power battery pack to be increased, and the case where the life of one phase of the motor winding is significantly shortened due to the motor winding generating heat for a long time is avoided, and therefore the symmetry and reliability of the motor are further improved. Also, no additional heating device is required, and the occupied space and cost can be reduced.

[0030] In a possible implementation, the step of determining the preset currents to be used by all phases of the motor windings to heat the power battery pack may in particular include: Determining a preset current based on a temperature of the power battery pack, the magnitude of the preset current being negatively correlated with the temperature of the power battery pack.

[0031] Temperature information of the power battery pack may be obtained using the VCU or BMS to determine the temperature of the power battery pack.

[0032] In a possible implementation, the step of determining the preset currents to be used by all phases of the motor windings to heat the power battery pack may in particular include: Determining a preset current based on the obtained heating command, the heating command being used to indicate a magnitude of the preset current.

[0033] In response to the input operation performed by the driver, the VCU refers to the current temperature information of the power battery pack to determine a corresponding heating command, and sends the heating command to the controller. The heating command is used to indicate the magnitude of the preset current.

[0034] In a possible implementation, the steps of controlling the inverter circuit to simultaneously output current to three phases of the motor winding and controlling the current input to all of the phases of the motor winding to sequentially reach a preset current include in particular: determining an amplitude and a phase of an input current for each phase of the motor winding based on a preset position angle and a preset current, the preset position angle representing an angle between the preset current and a d-axis of the motor; determining an amplitude and phase of an input voltage for each phase of the motor winding based on the amplitude and phase of the input current for each phase of the motor winding and the impedance for each phase of the motor winding; and determining a duty cycle of a control signal for the inverter circuit based on the amplitude of the input voltage; and determining a transmission time of the control signal for the inverter circuit based on the phase of the input voltage.

[0035] In a possible implementation, the step of controlling the current input to all phases of the motor windings to reach the preset current in sequence particularly includes the step of: controlling the preset position angle to vary periodically within a preset angle range.

[0036] In a possible implementation, the preset angle range is from 0° to 360°, and controlling the preset position angle to periodically change within the preset angle range. teeth: The method includes controlling the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a submultiple of 120. Positive submultiples of 120 include 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, and 120.

[0037] In a possible implementation, the preset angle range is from 0° to 120°, and controlling the preset position angle to periodically change within the preset angle range. teeth: The method includes controlling the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a submultiple of 60. Positive submultiples of 60 include 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

[0038] According to a fourth aspect, the present application further provides an electric vehicle, the electric vehicle including the powertrain provided in the above-mentioned implementation, and further including a power battery pack, an output terminal of the power battery pack is connected to an input terminal of the motor control unit, and the power battery pack is configured to supply a direct current for the powertrain.

[0039] The motor control unit provided in the above embodiment is applied to an electric vehicle, thus increasing the overall heating output of the motor. Also, the three phases of the motor winding are controlled to generate heat evenly. This increases the speed of heating the power battery pack, and avoids the case where the motor winding generates heat for a long time, which significantly shortens the life of the motor winding phases, thus improving the symmetry and reliability of the motor. Also, it avoids the case where an additional heating device is added to heat the power battery pack, thus reducing the cost of the electric vehicle. [Brief description of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram of a heating device for a power battery pack in the prior art.

[0041] [Diagram 2] FIG. 1 is a schematic diagram of an exemplary electric vehicle electrical system according to one embodiment of the present application.

[0042] [Diagram 3]FIG. 1 is a schematic diagram of an exemplary motor structure according to an embodiment of the present application.

[0043] [Figure 4] FIG. 2 is a schematic diagram of a motor control unit according to an embodiment of the present application.

[0044] [Diagram 5] FIG. 2 is a schematic diagram of an exemplary asymmetric three-phase current according to an embodiment of the present application.

[0045] [Figure 6] FIG. 2 is a schematic diagram of an exemplary three-phase current according to an embodiment of the present application.

[0046] [Figure 7] FIG. 2 is a schematic diagram of a control method for a motor control unit according to an embodiment of the present application.

[0047] [Figure 8] FIG. 1 is a schematic diagram of a powertrain according to an embodiment of the present application.

[0048] [Figure 9] 1 is a schematic diagram of an electric vehicle according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] In order to allow those skilled in the art to better understand the technical solutions provided in the embodiments of the present application, application scenarios of the technical solutions provided in the present application are first described below.

[0050] figure 2 1 is a schematic diagram of an exemplary electric vehicle electrical system according to one embodiment of the present application.

[0051] The electrical system of the electric vehicle shown in the figure mainly includes a motor control unit 10, a motor 20, a power battery pack 30, a high voltage power distribution unit 40, a DC-DC circuit 50, a low voltage battery 60, a DC charging circuit 70, and an AC charging circuit 80.

[0052] The power battery pack 30 is configured to supply high voltage direct current. A portion of the high voltage direct current is converted to alternating current using the high voltage power distribution unit 40 and the motor control unit 10, and the alternating current is supplied to the motor 20 to drive the electric vehicle. Another portion of the high voltage direct current is converted to low voltage direct current using the high voltage power distribution unit 40 and the DC-DC circuit 50, and the low voltage direct current is supplied for the low voltage battery 60 and the low voltage system of the electric vehicle.

[0053] When an electric vehicle is being charged, in some embodiments, the electric vehicle uses a DC charging circuit 70 to charge the power battery pack 30. In this case, the DC charging circuit 70 connects to a DC charging pile. This charging method is also called "DC fast charging."

[0054] In some other embodiments, the electric vehicle is charged using an AC charging circuit 80, which in this case connects to an AC charging pile. In this case, the AC charging circuit 80 may be an On-Board Charger (OBC). The OBC may also charge the low-voltage battery 60.

[0055] The operating principle of the motor 20 will now be described.

[0056] FIG. 3 is a schematic diagram of an exemplary motor structure according to an embodiment of the present application.

[0057] The motor 20 includes a housing 201 , a rotating shaft 202 , a stator 203 , and a rotor 204 .

[0058] The motor 20 is an oil-cooled motor, and the respective core, shaft 202, and rotor 204 of the housing 201 of the motor 20 are provided with a cooling loop. A cooling medium may reside and circulate within the cooling loop. The cooling medium is configured to cool the motor 20 and further configured to lubricate motor components, such as bearings, within the motor 20. The cooling medium may flow in and out of the motor cavity from the motor housing, or may flow in and out of the motor cavity from both ends of the motor.

[0059] The stator 203 of the motor is the stationary part of the motor and mainly includes an iron core and a stator winding.

[0060] The motor rotor 204 is the rotating component of the motor and is configured to convert electrical energy into mechanical energy.

[0061] The power losses of the motor 20 typically include portions such as copper losses, iron losses, and permanent magnet losses.

[0062] Copper loss refers to the heat generated when current flows through a copper conductor. The heating power P1 of copper loss is I1 2 ·R1, where I1 is the current flowing through the copper conductor and R1 is the resistance of the copper conductor.

[0063] Iron loss is loss that occurs in an AC magnetic field due to ferromagnetic materials of the motor 20, such as steel or silicon steel sheets, and includes hysteresis loss, eddy current loss, stray loss, and the like.

[0064] The permanent magnet losses are the corresponding eddy current losses that arise due to the fact that the permanent magnet material of the motor 20 is electrically conductive and therefore generates eddy currents due to induction in an alternating magnetic field. The heating power P2 of the permanent magnet losses is I2 2 ·R2, where I2 is the current generated in the permanent magnet material due to induction and R2 is the resistance of the eddy current loop.

[0065] Currently, a commonly used analysis method for the three-phase currents of the motor 20 is the Park's Transformation, which converts the stationary three-phase coordinates into rotating dq-axis coordinates for ease of analysis. The d-axis (direct axis) is also called the direct axis, and the d-axis is parallel to the motor's rotation axis (field axis). The q-axis (quadrature axis) is also called the quadrature axis, and is perpendicular to the motor's field axis.

[0066] Currently, the power battery pack can be heated by using a solution of arranging an additional heating device. However, the heating device occupies extra space and increases the hardware cost. In addition, the heating device also has problems such as uneven heating and low heating efficiency, and cannot effectively increase the temperature of the power battery pack, so that the electrochemical performance of the power battery pack cannot be effectively improved.

[0067] In order to solve the above problems, the present application provides a motor control unit, a powertrain, a control method, and an electric vehicle. An AC current is injected into a stator winding of a motor using a motor control unit, and a d-axis position of the AC current is determined based on a preset position angle. The preset position angle is periodically and regularly changed with respect to the actual d-axis so that the three-phase windings of the motor generate heat evenly and generate enough heat to heat the power battery pack.

[0068] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application are described below with reference to the accompanying drawings in the embodiments of the present application.

[0069] The terms "first" and "second" in the following description of this application are used solely for descriptive purposes and shall not be understood as an indication or implication of relative importance or an implicit indication of the quantity of the indicated technical features.

[0070] In this application, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense, for example, "connection" may be a fixed connection, a removable connection, an integral connection, a direct connection, or an indirect connection via an intermediate medium.

[0071] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present application provides a motor control unit, which will be described in detail below with reference to the accompanying drawings.

[0072] FIG. 4 is a schematic diagram of a motor control unit according to an embodiment of the present application.

[0073] The input of the motor control unit 10 is connected to a power battery pack 30 , and the output of the motor control unit is connected to the windings of the motor 20 .

[0074] Motor 20 includes three phase windings designated U, V, and W, respectively.

[0075] The motor control unit 10 includes a three-phase output, each phase of the output being connected to one phase of the motor windings of the motor.

[0076] The motor control unit 10 includes an inverter circuit 101 and a controller 102 .

[0077] The inverter circuit 101 is sometimes called a direct current (DC)-alternating current (AC) conversion circuit, and is sometimes called an inverter.

[0078] The inverter circuit 101 may be a three-phase two-level inverter circuit or a three-phase three-level inverter circuit. is limited In the following description, a case where the inverter circuit 101 is a three-phase two-level inverter circuit will be described as an example.

[0079] The input terminal of the inverter circuit 101 is the input terminal of the motor control unit 10 , and each phase of the output terminal of the inverter circuit 101 is connected to one phase of the motor winding of the motor 20 .

[0080] The inverter circuit 101 is configured to: convert a direct current supplied by the power battery pack 30 into an alternating current, and output the alternating current to the motor windings.

[0081] The controller 102 is configured to: control the inverter circuit 101 to output currents to the three phases of the motor windings simultaneously, and control the currents output to all phases of the motor windings to reach a preset current in sequence. The preset current is is limited Not determined.

[0082] First, the principles and ideas underlying the solution of the present application will be explained.

[0083] FIG. 5 is a schematic diagram of an exemplary asymmetric three-phase current according to an embodiment of the present application.

[0084] For a motor containing three phases U, V, and W, the vector coordinate axes of the motor's three-phase currents are shown in the figure.

[0085] The integral current vector is a sum vector including the current vectors of all the coordinate axes of the three-phase coordinate system (or the dq coordinate system). The illustrated integral current vector is represented by Is.

[0086] When it is envisaged to use the heat generated by the motor windings to heat the power battery pack, regardless of whether the current Is injected into the motor is direct or alternating, there is a problem that the motor windings generate heat non-uniformly. This is because, regardless of how the integral current vector Is is given, the projections Iu, Iv, Iw of Is on the coordinate axes of the three phases are not necessarily equal. Thus, the winding phases with a relatively large current component have a high heating power, the temperature rises quickly and the winding temperature limit is reached quickly. Moreover, the winding phases with a relatively low current component have a relatively low heating power and the temperature remains low.

[0087] However, in this case, the heating output of the motor cannot be increased by further increasing the magnitude of the current, and the heating output of the motor encounters a bottleneck. Therefore, the heating capacity of the motor winding cannot be fully used, resulting in an insufficient heating rate for the power battery pack, which has a relatively large impact on the life of the winding phase that generates heat for a long time. In this case, the symmetry and reliability of the motor are greatly affected.

[0088] The controller 102 in this embodiment of the present application controls the operation state of the inverter circuit 101 so that the inverter circuit 101 outputs current to the three phases of the motor windings simultaneously. In this case, current flows through each of the three phases of the motor windings, and the three phases of the motor windings generate heat, thus increasing the heating output of the motor. Furthermore, the controller controls the current input by the inverter circuit to all phases of the motor windings to reach a preset current sequentially. It can be understood that the preset current is a current value that can enable the motor windings to generate heat with a relatively high output. In some embodiments, the preset current is a maximum current value corresponding to the winding to maximize the heating output of the motor windings.

[0089] For example, the U-phase winding reaches the preset current first and starts to generate heat with a relatively high output. In this case, the current flowing through the V-phase winding and the W-phase winding is smaller than the preset current, and the V-phase winding and the W-phase winding generate heat with a relatively small output. After that, the V-phase winding reaches the preset current. At this time, the current flowing through the U-phase winding and the W-phase winding is smaller than the preset current, and the U-phase winding and the W-phase winding generate heat with a relatively small output, and the U-phase winding enters a buffer period, and the temperature no longer continues to rise. After that, the W-phase winding reaches the preset current. In this case, the current flowing through the U-phase winding and the V-phase winding is smaller than the preset current, and the U-phase winding and the V-phase winding generate heat with a relatively small output, and the V-phase winding also enters a buffer period, and the temperature no longer continues to rise. This cycle is repeated.

[0090] When the time during which the current in each phase of the motor winding is the preset current is relatively short, in other words, when the current flowing through each phase of the motor winding is switched at a relatively high frequency, the three phases of the motor winding will generate heat uniformly, and the heating output will be maintained at a relatively high state, so that the heat generating capacity of the motor winding can be fully utilized.

[0091] In some embodiments, the controller 102 in the above description may be an ASIC, a PLD, a DSP, or a combination thereof. The PLD may be a CPLD, an FPGA, a GAL, or any combination thereof. This is the case in this embodiment of the present application. is limited Not determined.

[0092] The inverter circuit 101 includes a controllable switching transistor. The type of the controllable switching transistor is is limited For example, the controllable switching transistor may be an IGBT, a MOSFET, or a SiC MOSFET.

[0093] The controller 102 may send a control signal to the controllable switch transistor to control the operating state of the controllable switch transistor. In some embodiments, the control signal is a PWM signal.

[0094] In conclusion, according to the motor control unit provided in this embodiment of the present application, all three phases of the motor winding can generate heat, and thus the overall heating output of the motor is increased. Also, the currents of the three phases of the motor winding are controlled to be preset currents in sequence, so that the three phases of the motor winding can generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This makes full use of the heat generating capacity of the motor winding, improves the heating speed of the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened due to the motor winding generating heat for a long time, and thus further improves the symmetry and reliability of the motor.

[0095] A specific control method of the motor control unit will be described below.

[0096] FIG. 6 is a schematic diagram of three-phase currents according to an embodiment of the present application.

[0097] Here, Id represents the preset current that all phases of the motor winding reach sequentially. The motor winding generates heat when the preset current passes through the motor winding. Therefore, within the allowable range of the motor winding parameters, the larger the magnitude of the preset current, the greater the heating output of the motor winding and the higher the heating rate of the power battery pack.

[0098] First, a method for determining the preset current will be described below.

[0099] In a possible implementation, the controller determines the preset current based on a temperature of the power battery pack, the magnitude of the preset current being negatively correlated with the temperature of the power battery pack.

[0100] For the power battery pack, within the same heating time, the lower the temperature of the power battery pack, the more heat is needed, in other words, a higher heating rate of the power battery pack is needed, a higher heating output of the motor winding is needed, and a corresponding larger magnitude of the preset current is needed.

[0101] Thus, the controller may determine the preset current based on the temperature of the power battery pack, with a lower temperature indicating a larger preset current being required to complete the heating of the power battery pack within the same heating time. The correspondence between temperature and preset current may be predetermined and stored in the form of a data table and recalled by the controller for use.

[0102] The controller may obtain temperature information of the power battery pack using the VCU to determine the temperature of the power battery pack. Alternatively, the controller may obtain temperature information of the power battery pack from the BMS to determine the temperature of the power battery pack.

[0103] In another possible implementation, the controller determines the preset current based on an obtained heating command, and the heating command is used to indicate the magnitude of the preset current.

[0104] The driver may determine the heating output level of the power battery pack based on the requirements (a higher heating output level indicates a higher heating rate) or adjust the heating time of the power battery pack (a shorter heating time corresponds to a higher heating output level). driver In response to the input operation performed by the VCU, the VCU refers to the current temperature information of the power battery pack to determine a corresponding heating command, and sends the heating command to the controller. The heating command is used to indicate the magnitude of the preset current.

[0105] The temperature information of the power battery pack is transmitted to the VCU by the BMS.

[0106] After obtaining the heating command, the controller determines the corresponding preset current. The correspondence between the heating command and the preset current may be predetermined and stored in the form of a data table and recalled by the controller for use.

[0107] The process by which the controller regulates the input currents of the three phases of the motor windings is described in detail below.

[0108] The controller first obtains the current preset position angle, which represents the angle between the preset current and the d-axis of the motor.

[0109] In the figure, an example is used in which the direction of the U-phase current is the d-axis of the motor, and the angle θ0 between the preset current Id and the d-axis of the motor is the preset position angle.

[0110] The controller determines the amplitude and phase of the input current for each phase of the motor winding based on the preset position angle θ and the preset current I, as will be described in detail below.

[0111] The controller controls the current output by the inverter circuit to each of the three phases of the motor winding to have a waveform that can exhibit alternating positive and negative conversion, such as a sine wave, a square wave, or a triangular wave. Hereinafter, a specific description will be given using a sine wave as an example. The same principle applies when using other types of waveforms. Details will not be described in this embodiment.

[0112] If t represents time, ω represents the frequency of the signal, and iu(t), iv(t), and iw(t) represent the instantaneous directions of current in the three phases U, V, and W, respectively, then we have the following relationships:

number

[0113] In this embodiment of the present application, the three phases of the motor winding are controlled to generate heat simultaneously to increase the heating output of the motor. The preset position angle θ0 is controlled to vary periodically so that Id overlaps the three phases U, V, W at different periods to implement that the currents of the three phases of the motor winding reach the preset current at different periods. When one phase of the motor winding generates heat with the preset current, this phase of the motor winding has the maximum heating output, and the other two phases of the motor winding generate heat with a relatively small heating output.

[0114] Ko The controller controls the preset position angle θ0 so that it periodically changes within the preset angle range, as will be described later in detail.

[0115] In a possible implementation, the preset angle range is from 0° to 360°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, where the value of the preset angle increment is a positive submultiple of 120.

[0116] In this embodiment of the present application, the preset time interval is limited The preset time interval is usually set to a relatively short time, for example, the second level time.

[0117] The positive divisors of 120 include 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, and 120. An example will be used below. In the following explanation, Iu, Iv, and Iw are the amplitudes of the currents of the three phases U, V, and W, respectively. Please refer to equation (a) for the instantaneous equations corresponding to each current. We will not list the equations one by one.

[0118] (1) First, we will describe an implementation where the preset angle increment is 120°, using an example where the preset time interval is 10 seconds (abbreviated as s).

[0119] [0s, 10s], θ0=0°, that is, Id is aligned with phase U. In this case, Iu=Id, Iv=Iw=Id / 2.

[0120] (10s,20s], θ0=120°, i.e., Id is aligned with the V phase. In this case, Iv=Id, Iu=Iw=Id / 2.

[0121] (20s,30s], θ0=240°, i.e., Id is aligned with the W phase. In this case, Iw=Id, Iu=Iv=Id / 2.

[0122] This process is then repeated periodically until heating of the power battery pack is complete.

[0123] (2) Below we describe an implementation where the preset angle increment is 60°, again using an example where the preset time interval is 10 s.

[0124] [0 sec, 10 sec], θ0=0°, i.e., Id is aligned with phase U. In this case, Iu=Id, Iv=Iw=Id / 2.

[0125] (10s,20s], θ0=60°, i.e., Id is aligned to the -W phase. In this case, Iw=Id, Iu=Iv=Id / 2.

[0126] (20s, 30s], θ0=120°, i.e., Id is aligned with the V phase. In this case, Iv=Id, Iu=Iw=Id / 2.

[0127] (30s, 40s], θ0=180°, i.e., Id is aligned with the -U phase. In this case, Iu=Id, Iv=Iw=Id / 2.

[0128] (40s,50s], θ0=240°, i.e., Id is aligned with the W phase. In this case, Iw=Id, Iv=Iu=Id / 2.

[0129] (50s,60s], θ0=300°, i.e., Id is aligned with the -V phase. In this case, Iv=Id, Iu=Iw=Id / 2.

[0130] This process is then repeated periodically until heating of the power battery pack is complete.

[0131] (3) Another implementation is described below where the preset angle increment is 120° and the preset time interval is still 10s. In this case, Id is not aligned to one phase of the axis, but is always kept at a constant angle relative to one phase of the axis. We use an example where the constant angle is 30°. In this case, we have the following cases:

[0132] [0 sec, 10 sec], θ0=30°. In this case, Iu=Iw=0.866*Id, Iv=0.

[0133] (10s,20s], θ0=150°, in this case Iv=Iu=0.866*Id, Iw=0.

[0134] (20s,30s], θ0=270°. In this case, Iw=Iv=0.866*Id, Iu=0.

[0135] This process is then repeated periodically until heating of the power battery pack is complete.

[0136] (4) An implementation where the preset angle increment is 60° is described below, and the preset time interval is still 10s. In this case, Id is not aligned to one phase of the axis, but is always kept at a constant angle relative to one phase of the axis. Using an example where the constant angle is 30°, we have the following cases:

[0137] [0s, 10s], θ0=30°. In this case, Iu=Iw=0.866*Id, Iv=0.

[0138] (10s,20s], θ0=90°. In this case, Iv=Iw=0.866*Id, Iu=0.

[0139] (20s,30s], θ0=150°. In this case, Iu=Iv=0.866*Id,Iw=0.

[0140] (30s,40s], θ0=210°. In this case, Iu=Iw=0.866*Id,Iv=0.

[0141] (40s,50s], θ0=270°. In this case, Iv=Iw=0.866*Id,Iu=0.

[0142] (50s,60s), θ0=330°. In this case, Iu=Iv=0.866*Id,Iw=0.

[0143] This process is then repeated periodically until heating of the power battery pack is complete.

[0144] In another possible implementation, the preset angle range is from 0° to 120°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive submultiple of 60.

[0145] Positive divisors of 60 include 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

[0146] Let us explain using an example below. In the following explanation, Iu, Iv, and Iw are the amplitudes of the currents of the three phases U, V, and W, respectively. For the instantaneous equations corresponding to each current, please refer to equation (a). We will not list the equations one by one.

[0147] (1) First, an implementation in which the preset angle increment is 60° is described, using an example in which the preset time interval is 10 s.

[0148] [0s, 10s], θ0=0°, that is, Id is aligned with phase U. In this case, Iu=Id, Iv=Iw=Id / 2.

[0149] (10s,20s], θ0=60°, i.e., Id is aligned with the W phase. In this case, Iw=Id, Iu=Iv=Id / 2.

[0150] (20s,30s], θ0=120°, i.e., Id is aligned with the V phase. In this case, Iv=Id, Iu=Iw=Id / 2.

[0151] This process is then repeated periodically until heating of the power battery pack is complete.

[0152] (2) An implementation is described below where the preset angle increment is 60°, and the preset time interval is still 10s. In this case, Id is not aligned to one phase of the axis, but is always kept at a constant angle relative to one phase of the axis. An example is used where the constant angle is 30°. In this case, we have the following cases:

[0153] [0s, 10s], θ0=30°. In this case, Iu=Iw=0.866*Id, Iv=0.

[0154] (10s,20s], θ0=90°. In this case, Iv=Iw=0.866*Id, Iu=0.

[0155] (20s,30s], θ0=150°. In this case, Iu=Iv=0.866*Id, Iw=0.

[0156] This process is then repeated periodically until heating of the power battery pack is complete.

[0157] After determining the amplitude and phase of the input current for each phase of the motor winding based on the preset position angle and the preset current, the controller determines the amplitude and phase of the input voltage for each phase of the motor winding based on the amplitude and phase of the input current for each phase of the motor winding and the impedance of each phase of the motor winding.

[0158] Voltage is equal to the product of current and impedance.

[0159] The impedance of the motor windings is an intrinsic parameter of the motor windings and may be predetermined and stored, and recalled for use by the controller.

[0160] The controller then determines a duty cycle of a control signal for the inverter circuit based on the amplitude of the input voltage, determines a transmission time of the control signal for the inverter circuit based on the phase of the input voltage, and controls the operating state of the inverter circuit using the control signal.

[0161] When the motor control unit is applied to an electric vehicle, the cooling loop of the electric vehicle can be directly reused to transfer the heat generated by the motor windings to the power battery pack, as will be described in detail below.

[0162] The cooling loop of the electric vehicle includes a first cooling loop and a second cooling loop. The first cooling loop is configured to perform heat exchange of the motor. For the method of cooling the motor by the loop, please refer to the description of FIG. 2. The cooling medium of the first cooling loop absorbs heat generated by the windings of the motor and transfers the heat to the cooling medium of the second cooling loop using a heat exchanger. The second cooling loop is configured to: perform heat exchange between the motor control unit and the power battery pack, and transfer the heat obtained from the motor control unit and the heat obtained from the heat exchanger to the power battery pack to heat the power battery pack.

[0163] The thermal cycle of the cooling medium in the first cooling loop is driven by a pump device. In some embodiments, the controller may further be configured to control the operating state of the pump device, for example, to control the output power, start time, and stop time of the pump device. It may be understood that the pump device may also be controlled by another controller, such as a vehicle control unit. In some implementations, when the power battery pack heats up, the controller controls the pump device to start to drive the cooling medium to circulate in the first cooling loop.

[0164] The inverter circuit of the above embodiment can be a three-phase two-level inverter circuit or a three-phase three-level inverter circuit. is limited The specific operating principle and implementation of the inverter circuit are relatively mature technologies, and the details will not be described in this embodiment.

[0165] In conclusion, according to the motor control unit provided in this embodiment of the present application, the motor windings of the three phases of the motor can be controlled to generate heat simultaneously, and thus the overall heating output of the motor is increased. The output current of the inverter circuit is further controlled so that the current of all phases of the motor windings reaches the preset current in sequence. When the current of the motor windings is the preset current, the motor windings have a relatively high heating output, and thus the three phases of the motor windings generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor windings can be maintained in a relatively high state. This makes full use of the heat generating capacity of the motor windings, increases the speed of heating the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened due to the motor windings generating heat for a long time, thus further improving the symmetry and reliability of the motor. Also, the case of adding an additional heating device to heat the power battery pack is avoided, and thus the hardware cost is reduced.

[0166] Based on the motor control unit provided in the above embodiment, the embodiment of the present application further provides a control method for the motor control unit, which will be described in detail below with reference to the accompanying drawings.

[0167] FIG. 7 is a schematic diagram of a control method of a motor control unit according to an embodiment of the present application.

[0168] The method includes the following steps.

[0169] S701: Determine the preset currents to be used by all phases of the motor windings to heat the power battery pack.

[0170] In a possible embodiment, the preset current is determined based on the temperature of the power battery pack, and the magnitude of the preset current is negatively correlated with the temperature of the power battery pack.

[0171] For the power battery pack, within the same heating time, a lower temperature of the power battery pack indicates that more heat is needed, in other words, a higher speed of heating the power battery pack is needed, a higher heating output of the motor windings is needed, and a corresponding larger magnitude of the preset current is needed.

[0172] Therefore, the preset current may be determined based on the temperature of the power battery pack, with a lower temperature indicating a larger magnitude of the preset current being required to complete heating of the power battery pack within the same heating time.

[0173] The temperature information of the power battery pack may be obtained using the VCU to determine the temperature of the power battery pack. Alternatively, the temperature information of the power battery pack may be obtained from the BMS to determine the temperature of the power battery pack.

[0174] In another possible implementation, the preset current is determined based on an obtained heating command, and the heating command is used to indicate the magnitude of the preset current.

[0175] The driver may determine the heating output level for the power battery pack based on the requirements (a higher heating output level indicates a higher heating rate) or adjust the heating time of the power battery pack (a shorter heating time corresponds to a higher heating output level). driver A heating command is generated in response to an input operation performed by the heating controller 100. The heating command is used to indicate a magnitude of a preset current.

[0176] S702: The inverter circuit is controlled so as to output currents to the three phases of the motor windings simultaneously, and the currents input to all the phases of the motor windings are controlled so as to reach the preset currents in sequence.

[0177] In some embodiments, S702 Yes The process includes:

[0178] S702a: Determine the amplitude and phase of the input current of each phase of the motor winding based on a preset position angle and a preset current, where the preset position angle represents the angle between the preset current and the d-axis of the motor.

[0179] In this case, in this method, the preset position angle needs to be controlled to change periodically within the preset angle range in order to implement that the three phases of the motor winding generate heat evenly.

[0180] First, a method for adjusting the preset position angle will be described below.

[0181] In a possible implementation, the preset angle range is from 0° to 360°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, where the value of the preset angle increment is a positive submultiple of 120.

[0182] In this embodiment of the present application, the preset time interval is limited The preset time interval is usually set to a relatively short time, for example, the second level time.

[0183] Positive divisors of 120 include 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, and 120.

[0184] In another possible implementation, the preset angle range is from 0° to 120°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive submultiple of 60.

[0185] Positive divisors of 60 include 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.

[0186] S702b: Determine the amplitude and phase of the input voltage for each phase of the motor winding based on the amplitude and phase of the input current for each phase of the motor winding and the impedance for each phase of the motor winding.

[0187] Voltage is equal to the product of current and impedance. The impedance of a motor winding is an intrinsic parameter of the motor winding and can be predetermined.

[0188] S702c: Determine a duty cycle of a control signal for the inverter circuit based on the amplitude of the input voltage, and determine a transmission time of the control signal for the inverter circuit based on the phase of the input voltage.

[0189] The operating states of the inverter circuits are controlled using the control signals to generate corresponding three-phase currents.

[0190] In conclusion, according to the control method of the motor control unit provided in this embodiment of the present application, all three phases of the motor winding can be controlled to generate heat, and thus the overall heating output of the motor is increased. In addition, the output current of the inverter circuit is controlled so that the current of all phases of the motor winding reaches the preset current in sequence. When the current of the motor winding is the preset current, the motor winding has a relatively high heating output, and thus the three phases of the motor winding generate heat uniformly. In addition, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This makes full use of the heat generating capacity of the motor winding, increases the heating speed of the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened due to the motor winding generating heat for a long time, and thus further improves the symmetry and reliability of the motor. In addition, no additional heating device is required, and the occupied space and cost can be reduced.

[0191] Based on the motor control unit provided in the above embodiment, an embodiment of the present application further provides a power train, which will be described in detail below with reference to the accompanying drawings.

[0192] FIG. 8 is a schematic diagram of a powertrain according to an embodiment of the present application.

[0193] The powertrain shown in the figure includes a motor control unit 10, a motor 20, a first cooling loop 801, a second cooling loop 802, a pump device 803, and a heat exchanger 804.

[0194] The first cooling loop 801 is configured to provide heat exchange for the motor 20 .

[0195] The pump device 803 is configured to drive the cooling medium in the first cooling loop 801 to circulate. In some embodiments, the cooling medium in the first cooling loop is a cooling oil, and in this application, the type of cooling oil is is limited Not determined.

[0196] The second cooling loop 802 is configured to exchange heat between the motor control unit 10 and the power battery pack 30. In some implementations, the cooling medium in the second cooling loop 802 is chilled water.

[0197] The heat exchanger 804 is configured to provide heat exchange between the cooling medium in the first cooling loop and the cooling medium in the second cooling loop.

[0198] Powertrain Movement The process of heating the power battery pack is described in detail below.

[0199] The circulation of the cooling medium in the first cooling loop 801 is shown by the dashed arrows in FIG. 8. Heat exchange is performed for the motor, so that the cooling medium in the first cooling loop 801 absorbs the heat generated by the motor windings. For the principle and process of generating heat by the motor windings, please refer to the related description in the above embodiment. The details will not be described here in this embodiment of the present application. Then, the cooling medium in the first cooling loop 801 transfers heat to the cooling medium in the second cooling loop 802 by using the heat exchanger 804.

[0200] The cooling medium in the second cooling loop 802 flows in from point A, first absorbing heat from the motor control unit 10, then absorbing the heat transferred by the cooling medium in the first cooling loop 801 as it passes through the heat exchanger 804 to sufficiently increase its temperature, and then passing through the power battery pack 30 to sufficiently heat the power battery pack 30. After heating the power battery pack 30, the cooling medium reaches point B. In some embodiments, points A and B may be connected to a radiator, a heat dissipation system, another heat exchanger, etc. of the electric vehicle to form a loop. This is the same as in this embodiment of the present application. is limited Not determined.

[0201] In conclusion, the motor control unit provided in the above embodiment is applied to the power train provided in this embodiment of the present application, and the controller of the motor control unit controls the inverter circuit to output current to the three phases of the motor winding simultaneously. In this case, all three phases of the motor winding generate heat, and thus the overall heating output of the motor increases. The controller also controls the output current of the inverter circuit so that the current of all phases of the motor winding sequentially reaches the preset current. When the current of the motor winding is the preset current, the motor winding has a relatively high heating output, and thus the three phases of the motor winding generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This makes full use of the heat generation capacity of the motor winding, increases the heating speed of the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened due to the motor winding generating heat for a long time, and thus further improves the symmetry and reliability of the motor. The first and second cooling loops of the powertrain can fully absorb the heat generated by the motor control unit and the motor windings to heat the power battery pack, thus further improving the heating speed of the power battery pack, and avoiding the case where an additional heating device is added to heat the power battery pack, thus reducing the cost of the powertrain and facilitating the design of a compact and highly integrated powertrain.

[0202] Based on the motor control unit and power train provided in the above embodiments, an embodiment of the present application further provides an electric vehicle, which will be described below with reference to the accompanying drawings.

[0203] FIG. 9 is a schematic diagram of an electric vehicle according to one embodiment of the present application.

[0204] The electric vehicle 900 shown in the figure includes a powertrain 800 and a power battery pack 101 .

[0205] The powertrain 800 includes a motor control unit, a motor, a first cooling loop, a second cooling loop, a pump device, and a heat exchanger. For the specific operation principles of the powertrain 800 and the motor control unit, please refer to the relevant description of the above embodiment. The details will not be described here in this embodiment.

[0206] The power battery pack 101 is configured to supply direct current to the power train 800 .

[0207] When the electric vehicle is started in a low temperature environment, under the action of the motor control unit, the power supplied by the power battery pack 101 for the power train 800 is Direct The flow of current allows the motor windings of the three phases of the motor to generate sufficient heat, and in this case, the power switching device of the motor control unit also generates corresponding heat. The power train 800 transfers the heat generated by the three phases of the motor windings and the heat generated by the motor control unit to the power battery pack 101 using a cooling loop, thereby heating the power battery pack 101.

[0208] In conclusion, the motor control unit provided in the above embodiment is applied to an electric vehicle, and the controller of the motor control unit controls the inverter circuit to output current to the three phases of the motor winding simultaneously. In this case, all three phases of the motor winding generate heat, and thus the overall heating output of the motor is increased. Also, the controller controls the output current of the inverter circuit so that the current of all phases of the motor winding sequentially reaches the preset current. When the current of the motor winding is the preset current, the motor winding has a relatively high heating output, and thus the three phases of the motor winding generate heat uniformly. Furthermore, by switching the magnitude of the current flowing, the heating output of each of the three phases of the motor winding can be maintained in a relatively high state. This makes full use of the heat generating capacity of the motor winding, increases the heating rate of the power battery pack, and avoids the case where the life of one phase of the motor winding is significantly shortened due to the motor winding generating heat for a long time, and thus further improves the symmetry and reliability of the motor. The first and second cooling loops of the powertrain of the electric vehicle can sufficiently absorb the heat generated by the motor control unit and the motor windings to heat up the power battery pack, thus further improving the speed of heating up the power battery pack.

[0209] It also avoids the case where an additional heating device is added to heat the power battery pack, thus reducing the cost of the electric vehicle.

[0210] In this application, it should be understood that "at least one" means one or more, and "plurality" means two or more. The term "and / or" is used to describe an association relationship between related objects and indicates that three relationships may exist. For example, "A and / or B" may indicate three cases: only A is present, only B is present, and both A and B are present, where A and B may be singular or plural. The character " / " generally indicates an "or" relationship between associated objects. "At least one of the following items" or similar expressions indicates any combination of these items, including any combination of a single item or multiple items. For example, at least one item of a, b, or c may indicate: a, b, c, "a and b," "a and c," "b and c," or "a, b, and c," where a, b, and c may be singular or plural.

[0211] It should be noted that the above embodiments are merely intended to illustrate the technical solutions of the present application, but are not intended to limit the present application. Although the present application has been described in detail with reference to the above embodiments, it should be understood that those skilled in the art may make modifications to the technical solutions described in the above embodiments or make equivalent substitutions to some technical features thereof without departing from the scope of the technical solutions of the embodiments of the present application.

Claims

1. a motor control unit, an input end of the motor control unit configured to connect to a power battery pack and an output end of the motor control unit configured to connect to three phases of a motor winding of a motor, the motor control unit having an inverter circuit and a controller; an input terminal of the inverter circuit is the input terminal of the motor control unit, and each phase of an output terminal of the inverter circuit is connected to one phase of a motor winding of the motor; The controller: controls the inverter circuit to simultaneously output current to three phases of the motor windings, and sequentially controls the current input to all of the phases of the motor windings to reach a preset current; determining an amplitude and a phase of an input current for each phase of the motor winding based on a preset position angle and the preset current, the preset position angle representing an angle between the preset current and a d-axis of the motor; determining an amplitude and phase of an input voltage for each phase of the motor winding based on the amplitude and phase of an input current for each phase of the motor winding and an impedance for each phase of the motor winding; determining a duty cycle of a control signal for the inverter circuit based on the amplitude of the input voltage, and determining a transmission time of the control signal for the inverter circuit based on the phase of the input voltage. Motor control unit.

2. The controller is further configured to determine the preset current based on a temperature of the power battery pack, the magnitude of the preset current being negatively correlated with the temperature of the power battery pack.

2. The motor control unit of claim 1.

3. The controller is further configured to determine the preset current based on an obtained heating command, the heating command being used to indicate a magnitude of the preset current. The motor control unit of claim 1 .

4. the controller is configured to control the preset position angle to vary periodically within a preset angle range; A motor control unit according to any one of claims 1 to 3.

5. the preset angle range is from 0° to 360°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive submultiple of 120; 5. The motor control unit according to claim 4.

6. the preset angle range is from 0° to 120°, and the controller controls the preset position angle to change periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a positive submultiple of 60; 5. The motor control unit according to claim 4.

7. The controller adjusts the current output by the inverter circuit to each of the three phases of the motor windings to the following waveforms: Sine, square or triangle wave configured to control the input to be one of: The motor control unit of claim 1 .

8. The inverter circuit is a three-phase two-level inverter circuit or a three-phase three-level inverter circuit. The motor control unit of claim 1 .

9. The controller is further configured to control an operating state of a pump device, the motor performing heat exchange with a first cooling loop, and using the pump device to drive a cooling medium circulating in the first cooling loop. A motor control unit according to any preceding claim.

10. A control method for a motor control unit, the method being used for heating a power battery pack, the motor control unit having an inverter circuit and a controller, an input end of the inverter circuit is an input end of the motor control unit and is configured to connect to the power battery pack, and each phase of an output end of the inverter circuit is connected to one phase of a motor winding of a motor, the control method for the motor control unit includes: determining a preset current for use by all phases of a motor winding to heat the power battery pack; controlling the inverter circuit to simultaneously output current to three phases of the motor windings; and controlling the current input to all of the phases of the motor windings to sequentially reach the preset current; The steps of controlling the inverter circuit to simultaneously output current to three phases of the motor windings, and controlling the current input to all of the phases of the motor windings to sequentially reach the preset current, include: determining an amplitude and a phase of an input current for each phase of the motor winding based on a preset position angle and the preset current, the preset position angle representing an angle between the preset current and a d-axis of the motor; determining an amplitude and phase of an input voltage for each phase of the motor winding based on the amplitude and phase of an input current for each phase of the motor winding and an impedance for each phase of the motor winding; and determining a duty cycle of a control signal of the inverter circuit based on the amplitude of the input voltage, and determining a transmission time of the control signal of the inverter circuit based on the phase of the input voltage. Control methods.

11. The step of determining a preset current to be used by all phases of a motor winding to heat the power battery pack comprises: determining the preset current based on a temperature of the power battery pack, the magnitude of the preset current being negatively correlated with the temperature of the power battery pack; The control method according to claim 10.

12. The step of determining a preset current to be used by all phases of a motor winding to heat the power battery pack comprises: determining the preset current based on an obtained heating command, the heating command being used to indicate a magnitude of the preset current; The control method according to claim 10.

13. The step of controlling the current input to all of the phases of the motor winding to sequentially reach the preset current comprises: controlling the preset position angle to periodically change within a preset angle range; A control method according to any one of claims 10 to 12.

14. The preset angle range is from 0° to 360°, and the step of controlling the preset position angle to periodically change within the preset angle range includes: controlling the preset position angle to vary periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a submultiple of 120; The control method according to claim 13.

15. The preset angle range is from 0° to 120°, and the step of controlling the preset position angle to periodically change within the preset angle range includes: controlling the preset position angle to vary periodically based on a preset time interval and a preset angle increment, the value of the preset angle increment being a submultiple of 60; The control method according to claim 13.

16. A powertrain comprising the motor control unit according to any one of claims 1 to 9, further comprising a motor, a first cooling loop, a second cooling loop, a pump device, and a heat exchanger; the first cooling loop configured to provide heat exchange for the motor; the second cooling loop configured to exchange heat between the motor control unit and a power battery pack; the pumping device is configured to circulate a cooling medium in the first cooling loop; the heat exchanger is configured to exchange heat between the cooling medium in the first cooling loop and a cooling medium in the second cooling loop; Powertrain.

17. 17. An electric vehicle comprising the powertrain of claim 16, further comprising a power battery pack; an output end of the power battery pack connected to the input end of the motor control unit; the power battery pack is configured to supply direct current for the powertrain; Electric car.

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