Motor stalling test method and device and vehicle electric drive system

Abstract

The invention provides a motor stalling test method and device and a vehicle electric drive system, and belongs to the field of automobiles, and the method comprises the steps: collecting the current of a permanent magnet synchronous motor and the rotating speed of the motor; acquiring a first reference current of the permanent magnet synchronous motor; the amplitude of the first reference current is kept unchanged, components of the first reference current on the direct axis and the quadrature axis are reconstructed based on the motor rotating speed, and second reference current is obtained, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor rotating speed of the permanent magnet synchronous motor tends to 0; adjusting the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current; and when it is detected that the motor rotating speed of the permanent magnet synchronous motor is not greater than the preset rotating speed, performing a locked-rotor test on the permanent magnet synchronous motor. External force does not need to be applied to the permanent magnet synchronous motor, the permanent magnet synchronous motor is controlled to be locked by the internal logic of the permanent magnet synchronous motor, the locked-rotor test cost is reduced, and the convenience is improved.

Description

Technical Field

[0001] The present application relates to the automotive field, and in particular to a motor stall test method, device and vehicle electric drive system. Background Art

[0002] Permanent magnet synchronous motors are widely used in the electric drive systems of new energy vehicles due to their advantages such as high efficiency, high power density and wide speed regulation range. Among them, the stalling capability of permanent magnet synchronous motors is an important assessment indicator.

[0003] In the related art, in the stall test of the permanent magnet synchronous motor, the output shaft of the permanent magnet synchronous motor being tested is locked using a mechanical locking mechanism in the test bench, and the permanent magnet synchronous motor is energized. When the output torque of the permanent magnet synchronous motor reaches the stall torque, since the output shaft of the permanent magnet synchronous motor has been locked, the motor speed of the permanent magnet synchronous motor is 0, so that the permanent magnet synchronous motor is in a stall state, and then the permanent magnet synchronous motor is subjected to a stall test.

[0004] However, since a bench mechanical locking mechanism is required, the cost of the stall test is high and the convenience of the motor stall test is low. Summary of the invention

[0005] The embodiments of the present application provide a motor stall test method, device and vehicle electric drive system, which can reduce the cost of the stall test and improve the convenience of the motor stall test. The technical solution is as follows:

[0006] In one aspect, a motor stall test method is provided, the method comprising:

[0007] Collect the current and motor speed of the permanent magnet synchronous motor;

[0008] Acquire a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque;

[0009] Keeping the amplitude of the first reference current unchanged, reconstructing the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain a second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor tends to 0;

[0010] Based on the current of the permanent magnet synchronous motor and the second reference current, adjusting the AC voltage of the permanent magnet synchronous motor so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current;

[0011] When it is detected that the motor speed of the permanent magnet synchronous motor is not greater than the preset speed, a stall test is performed on the permanent magnet synchronous motor. The motor speed of the permanent magnet synchronous motor being not greater than the preset speed indicates that the permanent magnet synchronous motor is currently in a stall state.

[0012] In a possible implementation, collecting the current of the permanent magnet synchronous motor includes:

[0013] Collecting the three-phase alternating current of the permanent magnet synchronous motor;

[0014] The three-phase alternating current is transformed into an α-axis current and a β-axis current by using Clark transformation;

[0015] The α-axis current and the β-axis current are transformed into a direct-axis current and a quadrature-axis current based on the rotor position of the permanent magnet synchronous motor by using Park transformation.

[0016] In a possible implementation manner, obtaining a first reference current of the permanent magnet synchronous motor includes:

[0017] Acquiring the stall torque and the bus voltage of the permanent magnet synchronous motor;

[0018] In the reference current table, query the reference current corresponding to the stall torque, the bus voltage and the motor speed, and determine the queried reference current as the first reference current;

[0019] The reference current table stores reference currents corresponding to any torque, any bus voltage and any click speed.

[0020] In a possible implementation, adjusting the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current so that the current of the permanent magnet synchronous motor after adjustment approaches the second reference current includes:

[0021] Adopting a proportional-integral control algorithm, based on the current of the permanent magnet synchronous motor and the second reference current, determining a direct-axis reference voltage and a quadrature-axis reference voltage;

[0022] Using Park inverse transformation to transform the direct-axis reference voltage and the quadrature-axis reference voltage into an α-axis reference voltage and a β-axis reference voltage;

[0023] generating a three-phase duty cycle based on the α-axis reference voltage and the β-axis reference voltage;

[0024] According to the three-phase duty cycle, the bus voltage is converted into an AC voltage of the permanent magnet synchronous motor, so that the current of the permanent magnet synchronous motor tends to the second reference current after adjustment.

[0025] In a possible implementation, the first reference current includes a first direct-axis reference current and a first quadrature-axis reference current; and the step of keeping the amplitude of the first reference current unchanged and reconstructing the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain the second reference current includes:

[0026] Determine a target reference current angle based on the inverse of the first direct-axis reference current, the first quadrature-axis reference current, and the motor speed, so that the motor speed of the permanent magnet synchronous motor tends to 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle;

[0027] Based on the amplitude of the first reference current and the target reference current angle, a second direct-axis reference current and a second quadrature-axis reference current are determined, and the second direct-axis reference current and the second quadrature-axis reference current are determined as the second reference current.

[0028] In a possible implementation, determining the target reference current angle based on the negative number of the first direct-axis reference current, the first quadrature-axis reference current, and the motor speed includes:

[0029] determining an initial reference current angle based on the inverse of the first direct-axis reference current and the first quadrature-axis reference current;

[0030] Determining a current compensation angle based on a difference between the motor speed and a target speed, wherein the target speed is 0;

[0031] The sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle.

[0032] In a possible implementation, the current compensation angle is not less than a first angle and not greater than a second angle, the first angle is equal to the negative of the initial reference current angle, and the second angle is equal to the difference between 90 degrees and the initial reference current angle.

[0033] In a possible implementation, when the current of the permanent magnet synchronous motor is equal to the second reference current, the sum of the permanent magnet torque and the reluctance torque of the permanent magnet synchronous motor is equal to 0, and the permanent magnet torque and the reluctance torque are equal in magnitude and opposite in direction.

[0034] On the other hand, a motor stall test device is provided, the device comprising:

[0035] An acquisition module is used to acquire the current and motor speed of the permanent magnet synchronous motor;

[0036] An acquisition module, used for acquiring a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque;

[0037] a reconstruction module, configured to keep the amplitude of the first reference current unchanged, and reconstruct the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain a second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor approaches 0;

[0038] an adjustment module, configured to adjust the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current, so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current;

[0039] The test module is used to perform a stall test on the permanent magnet synchronous motor when it is detected that the motor speed of the permanent magnet synchronous motor is not greater than a preset speed. The motor speed of the permanent magnet synchronous motor is not greater than the preset speed, indicating that the permanent magnet synchronous motor is currently in a stall state.

[0040] In a possible implementation, the acquisition module is used to:

[0041] Collecting the three-phase alternating current of the permanent magnet synchronous motor;

[0042] The three-phase alternating current is transformed into an α-axis current and a β-axis current by using Clark transformation;

[0043] The α-axis current and the β-axis current are transformed into a direct-axis current and a quadrature-axis current based on the rotor position of the permanent magnet synchronous motor by using Park transformation.

[0044] In a possible implementation, the acquisition module is used to:

[0045] Acquiring the stall torque and the bus voltage of the permanent magnet synchronous motor;

[0046] In the reference current table, query the reference current corresponding to the stall torque, the bus voltage and the motor speed, and determine the queried reference current as the first reference current;

[0047] The reference current table stores reference currents corresponding to any torque, any bus voltage and any click speed.

[0048] In a possible implementation, the adjustment module is used to:

[0049] Adopting a proportional-integral control algorithm, based on the current of the permanent magnet synchronous motor and the second reference current, determining a direct-axis reference voltage and a quadrature-axis reference voltage;

[0050] Using Park inverse transformation to transform the direct-axis reference voltage and the quadrature-axis reference voltage into an α-axis reference voltage and a β-axis reference voltage;

[0051] generating a three-phase duty cycle based on the α-axis reference voltage and the β-axis reference voltage;

[0052] According to the three-phase duty cycle, the bus voltage is converted into an AC voltage of the permanent magnet synchronous motor, so that the current of the permanent magnet synchronous motor tends to the second reference current after adjustment.

[0053] In a possible implementation, the first reference current includes a first straight-axis reference current and a first quadrature-axis reference current; and the reconstruction module is configured to:

[0054] Determine a target reference current angle based on the inverse of the first direct-axis reference current, the first quadrature-axis reference current, and the motor speed, so that the motor speed of the permanent magnet synchronous motor tends to 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle;

[0055] Based on the amplitude of the first reference current and the target reference current angle, a second direct-axis reference current and a second quadrature-axis reference current are determined, and the second direct-axis reference current and the second quadrature-axis reference current are determined as the second reference current.

[0056] In a possible implementation, the reconstruction module is used to:

[0057] determining an initial reference current angle based on the inverse of the first direct-axis reference current and the first quadrature-axis reference current;

[0058] Determining a current compensation angle based on a difference between the motor speed and a target speed, wherein the target speed is 0;

[0059] The sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle.

[0060] In a possible implementation, the current compensation angle is not less than a first angle and not greater than a second angle, the first angle is equal to the negative of the initial reference current angle, and the second angle is equal to the difference between 90 degrees and the initial reference current angle.

[0061] In a possible implementation, when the current of the permanent magnet synchronous motor is equal to the second reference current, the sum of the permanent magnet torque and the reluctance torque of the permanent magnet synchronous motor is equal to 0, and the permanent magnet torque and the reluctance torque are equal in magnitude and opposite in direction.

[0062] On the other hand, a vehicle electric drive system is provided, which includes a permanent magnet synchronous motor, a motor controller and a memory, wherein at least one computer program is stored in the memory, and the at least one computer program is executed by the motor controller to implement the motor stall test method as described in the above aspects.

[0063] On the other hand, a computer-readable storage medium is provided, wherein at least one computer program is stored in the computer-readable storage medium, and when the at least one computer program is executed, the motor stall test method as described in the above aspects is implemented.

[0064] The beneficial effects of the technical solution provided by the embodiments of the present application include at least:

[0065] The embodiments of the present application provide a motor stall test method, device and vehicle electric drive system, wherein the first reference current is the current required when the output torque of the permanent magnet synchronous motor reaches the stall torque, and the second reference current is obtained by reconstructing the components of the first reference current on the direct axis and the quadrature axis while keeping the amplitude of the first reference current unchanged, and then the AC voltage of the permanent magnet synchronous motor is adjusted according to the difference between the current current of the permanent magnet synchronous motor and the second reference current, so that the current of the permanent magnet synchronous motor tends to the second reference current. At this time, the speed of the permanent magnet synchronous motor tends to 0 and the current amplitude of the permanent magnet synchronous motor is equal to the current amplitude required to reach the stall torque, thereby ensuring that the permanent magnet synchronous motor is in a stall state without applying external force to the permanent magnet synchronous motor, and then performing a stall test on the permanent magnet synchronous motor, without locking the output shaft of the permanent magnet synchronous motor, and the permanent magnet synchronous motor is controlled by the internal logic of the permanent magnet synchronous motor. This is conducive to reducing the cost of the stall test and improving the convenience of the stall test on the permanent magnet synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0067] Figure 1 is a flow chart of a motor control method provided by an embodiment of the present application;

[0068] Figure 2 is a trajectory diagram of a direct-axis current and a quadrature-axis current provided in an embodiment of the present application;

[0069] Figure 3 is a flow chart of a motor stall test method provided in an embodiment of the present application;

[0070] Figure 4 is a flow chart of a current reconstruction method provided in an embodiment of the present application;

[0071] Figure 5 is a flow chart of another motor control method provided by an embodiment of the present application;

[0072] Figure 6 It is a structural schematic diagram of a motor stall test device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0073] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0074] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present application and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0075] The vehicle electric drive system of new energy vehicles mainly includes drive motors and motor controllers. Permanent magnet synchronous motors are widely used in vehicle electric drive systems of new energy vehicles due to their advantages such as high efficiency, high power density, and wide speed regulation range. The control strategies of permanent magnet synchronous motors include direct torque control strategy and vector control strategy. Among them, the vector control strategy has the advantages of fast torque response, high control accuracy, and small torque pulsation, and is widely used in vehicle electric drive systems of new energy vehicles.

[0076] In the related technology, the stalling capability of the vehicle electric drive system of new energy vehicles is a very important assessment indicator. In the stalling test of the permanent magnet synchronous motor, the mechanical locking mechanism in the test bench is required to mechanically lock the output shaft of the tested permanent magnet synchronous motor on the test bench to ensure that when the output torque of the permanent magnet synchronous motor reaches the stalling torque, the speed of the permanent magnet synchronous motor is 0, so that the permanent magnet synchronous motor is in a stalled state, so as to perform a stalling test on the permanent magnet synchronous motor. However, due to the need to equip the bench with a mechanical locking mechanism, the cost of the stalling test is high and the convenience of the motor stalling test is low.

[0077] Based on this, an embodiment of the present application proposes a scheme for performing a stall test on a permanent magnet synchronous motor by using a vector control strategy under the condition of canceling the mechanical locking mechanism of the test bench. This scheme can ensure that the stall test is performed on the output shaft of the permanent magnet synchronous motor under no-load conditions, that is, the stall test is performed without applying external force to the output shaft of the permanent magnet synchronous motor. The detailed process can be found in the following embodiments.

[0078] For ease of understanding, the process of controlling a permanent magnet synchronous motor using a vector control strategy is first described below.

[0079] Among them, the vector control of permanent magnet synchronous motor is also called field-oriented control. The control principle is to establish a synchronous rotating coordinate system of the motor rotor through magnetic field orientation, and convert the three-phase AC current of the motor stator into direct-axis current and quadrature-axis current through Clark transformation and Park transformation. The direct axis is also called the d-axis, and the quadrature axis is also called the q-axis. The torque and magnetic field in the current of the motor stator are decoupled, realizing control similar to that of a DC motor, simplifying the control difficulty of the permanent magnet synchronous motor, and having the advantages of fast torque response, small output torque pulsation, and high torque accuracy.

[0080] Figure 1 is a flow chart of a motor control method provided in an embodiment of the present application, see Figure 1 , the method comprising:

[0081] 1. The power module converts the DC power of the high-voltage battery into AC power to provide three-phase AC voltage for the permanent magnet synchronous motor. The power module is also called an inverter.

[0082] 2. During the operation of the permanent magnet synchronous motor, the current sensor collects the three-phase AC current of the permanent magnet synchronous motor, and the three-phase AC current is recorded as Iu, Iv, and Iw respectively.

[0083] 3. The position sensor collects the rotor position θ and motor speed Spd of the permanent magnet synchronous motor.

[0084] Among them, the rotor position θ refers to the angle between the rotor magnetic pole axis (the axis of the N pole or S pole) and the stator A phase winding axis. This angle is fixed in space, but it changes as the rotor rotates. The rotor position θ is an important parameter in vector control, which determines the distribution of motor current and the size and direction of output torque. By accurately controlling the rotor position, precise control and high-performance operation of the motor can be achieved.

[0085] The motor speed Spd generally refers to the number of revolutions per minute (RPM) of the motor.

[0086] 4. Clark transformation is used to transform the three-phase AC current into α-axis current Iα and β-axis current Iβ. The transformation method is shown in formula (1):

[0087]

[0088] 5. Use Park transformation to transform the α-axis current Iα and the β-axis current Iβ into the d-axis current Id and the q-axis current Iq. The transformation method is shown in formula (2):

[0089]

[0090] Among them, the d-axis current is also called the direct-axis current, and the q-axis current is also called the quadrature-axis current.

[0091] 6. The vehicle controller VCU obtains the target torque, and queries the reference current table based on the target torque, bus voltage and motor speed to obtain the d-axis reference current Idref and the q-axis reference current Iqref. The reference current table is generated offline after data fitting processing for the permanent magnet synchronous motor bench calibration.

[0092] Among them, the d-axis reference current is also called the direct-axis reference current, and the q-axis reference current is also called the quadrature-axis reference current.

[0093] 7. Using the proportional integral control algorithm (PI controller), the d-axis reference voltage U is determined based on the difference between the actual current value (Id and Iq) of the permanent magnet synchronous motor and the reference current value (Idref and Iqref). d and q-axis reference voltage U q .

[0094] Among them, the d-axis reference voltage is also called the direct-axis reference voltage, and the q-axis reference voltage is also called the quadrature-axis reference voltage.

[0095] Among them, the proportional-integral control algorithm is also called the PI (Proportional-Integral) controller, which is used to control the feedback loop in the system, and adjusts the output signal to make the actual output of the system as close to the expected value as possible. The PI controller is a feedback control strategy, including a proportional part P and an integral part I. The proportional part P adjusts the control output according to the current error (the difference between the reference value and the actual value), and there may be a steady-state error. The integral part I takes into account past errors and gradually eliminates steady-state errors to ensure that the system reaches the set target in long-term operation.

[0096] 8. Use Park inverse transformation to convert the d-axis reference voltage U d and q-axis reference voltage U q Transformed into α-axis reference voltage U α and β-axis reference voltage U β The transformation method is shown in formula (3):

[0097]

[0098] 9. Using SVPWM algorithm, based on α-axis reference voltage U α and β-axis reference voltage U β Generate three-phase duty ratios Uduty, Vduty, and Wduty.

[0099] Among them, the SVPWM (Space Vector Pulse Width Modulation) algorithm is a modulation technology used to control the output of the power module three-phase AC voltage. The SVPWM algorithm uses the position of the voltage vector in space to convert the DC bus voltage into the required three-phase AC voltage.

[0100] Among them, the three-phase duty cycle refers to the proportion of the effective voltage of each phase output by the power module to the total cycle.

[0101] 10. The power module inverts the DC bus voltage of the high-voltage battery into the three-phase AC voltage of the motor stator according to the three-phase duty cycle Uduty, Vduty, and Wduty, thereby adjusting the three-phase AC voltage of the motor stator so that the actual current value of the permanent magnet synchronous motor approaches the reference current value obtained by looking up the table, so that the permanent magnet synchronous motor outputs the target torque.

[0102] The torque output by the permanent magnet synchronous motor is related to the actual current value of the permanent magnet synchronous motor. The output torque equation of the permanent magnet synchronous motor is shown in formula (4).

[0103]

[0104] Among them, T qrepresents the output torque of the permanent magnet synchronous motor, P represents the number of motor pole pairs, λ f represents the magnetic flux constant, L d Indicates the motor d-axis inductance, L q Represents the motor q-axis inductance, I d Indicates the motor d-axis current, I q Indicates the motor q-axis current.

[0105] The output torque of the permanent magnet synchronous motor can be divided into permanent magnet torque T p and reluctance torque T r , permanent magnet torque T p and reluctance torque T r The expressions of are shown in formula (5) and formula (6).

[0106]

[0107]

[0108] Among them, when the permanent magnet synchronous motor is working normally, the d-axis current Id and the q-axis current Iq work in the second quadrant and the third quadrant. Figure 2 As shown, the horizontal axis represents the d-axis current Id, and the vertical axis represents the q-axis current Iq. The trajectories of the d-axis current Id and the q-axis current Iq are 0→A1→A2→A3. f >0,L d <L q Therefore, no matter whether the d-axis current Id and the q-axis current Iq operate in the second quadrant or the third quadrant, the permanent magnet torque and reluctance torque output by the permanent magnet synchronous motor are in the same direction during normal operation.

[0109] In order to make the permanent magnet synchronous motor reach the stalled state without applying external force to the permanent magnet synchronous motor, the components of the current on the direct axis and the quadrature axis are reconstructed under the condition that the current amplitude remains unchanged, so that the permanent magnet torque output by the permanent magnet synchronous motor is the same as the reluctance torque and the direction is opposite, thereby ensuring that the output torque of the permanent magnet synchronous motor is 0, and then the motor speed of the permanent magnet synchronous motor tends to 0, so that the permanent magnet synchronous motor reaches the stalled state under the condition that the output shaft is unloaded.

[0110] Figure 3 is a flow chart of a motor stall test method provided in an embodiment of the present application, see Figure 3 , the method comprising:

[0111] 301. Collect the current and motor speed of the permanent magnet synchronous motor.

[0112] In a possible implementation, the current of the permanent magnet synchronous motor is collected by a current sensor to obtain the current collected by the current sensor.

[0113] In a possible implementation, the motor speed of the permanent magnet synchronous motor is collected by a position sensor to obtain the motor speed collected by the position sensor.

[0114] In one possible implementation, the three-phase AC current of the permanent magnet synchronous motor is collected, and the three-phase AC current is converted into α-axis current and β-axis current using Clark transformation; and the α-axis current and β-axis current are converted into direct-axis current and quadrature-axis current based on the rotor position of the permanent magnet synchronous motor using Park transformation.

[0115] Among them, the method of converting the three-phase AC current into the α-axis current and the β-axis current is shown in the above formula (1), and the method of converting the α-axis current and the β-axis current into the direct-axis current and the quadrature-axis current is shown in the above formula (2), which will not be repeated here.

[0116] It should be noted that the current collected in step 301 is the actual current of the permanent magnet synchronous motor. The purpose of the embodiment of the present application is to control the three-phase AC voltage of the permanent magnet synchronous motor so that the actual direct-axis current and quadrature-axis current of the permanent magnet synchronous motor approach the required direct-axis current and quadrature-axis current, so as to ensure that the output torque of the permanent magnet synchronous motor is 0, thereby achieving the goal of the permanent magnet synchronous motor having a speed of 0.

[0117] 302. Obtain a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque.

[0118] In one possible implementation, the stall torque and the bus voltage of the permanent magnet synchronous motor are obtained; in a reference current table, a reference current corresponding to the stall torque, the bus voltage and the motor speed is queried, and the queried reference current is determined as the first reference current.

[0119] The reference current table stores reference currents corresponding to any torque, any bus voltage and any click speed. The reference current table is generated offline after data fitting processing for the permanent magnet synchronous motor bench calibration.

[0120] Optionally, the first reference current includes a first straight-axis reference current and a first quadrature-axis reference current.

[0121] In the embodiment of the present application, when the permanent magnet synchronous motor works normally, it is divided into two cases. In the first case, the output torque of the permanent magnet synchronous motor is positive torque, then the first straight-axis reference current is less than 0, and the first quadrature-axis reference current is greater than 0, that is, the first straight-axis reference current and the first quadrature-axis reference current work in the second quadrant. In the second case, the output torque of the permanent magnet synchronous motor is negative torque, then the first straight-axis reference current is less than 0, and the first quadrature-axis reference current is less than 0, that is, the first straight-axis reference current and the first quadrature-axis reference current work in the third quadrant.

[0122] 303. Keep the amplitude of the first reference current unchanged, and reconstruct the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain the second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor tends to 0.

[0123] The first reference current includes a component on the direct axis and a component on the quadrature axis, the component on the direct axis is the first direct axis reference current, and the component on the quadrature axis is the first quadrature axis reference current. The second reference current includes a component on the direct axis and a component on the quadrature axis, the component on the direct axis is the second direct axis reference current, and the component on the quadrature axis is the second quadrature axis reference current. The amplitude of the first reference current is equal to the amplitude of the second reference current, that is, the vector sum of the first direct axis reference current and the first quadrature axis reference current is equal to the vector sum of the second direct axis reference current and the second quadrature axis reference current. However, the magnitude of the first direct axis reference current is not necessarily equal to the magnitude of the second direct axis reference current, and the magnitude of the first quadrature axis reference current is not necessarily equal to the magnitude of the second quadrature axis reference current. The second direct axis reference current and the second quadrature axis reference current are obtained by reconstructing the first direct axis reference current and the first quadrature axis reference current.

[0124] In an embodiment of the present application, the first reference current is reconstructed to obtain a second reference current so that the reconstructed second reference current satisfies the following condition: when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor tends to 0.

[0125] The second reference current includes a second direct-axis reference current and a second quadrature-axis reference current, and when the output torque calculated according to the second direct-axis reference current and the second quadrature-axis reference current according to the above formula (4) is equal to 0, the motor speed of the permanent magnet synchronous motor tends to 0. That is, the permanent magnet torque calculated according to the above formula (5) and the reluctance torque calculated according to the above formula (6) according to the second direct-axis reference current and the second quadrature-axis reference current are equal in magnitude and opposite in direction.

[0126] In a possible implementation, the first reference current includes a first straight-axis reference current and a first quadrature-axis reference current. Step 303 includes the following steps 3031-3032.

[0127] 3031. Determine a target reference current angle based on the inverse of the first straight-axis reference current, the first quadrature-axis reference current, and the motor speed, so that the motor speed of the permanent magnet synchronous motor approaches 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle.

[0128] The current angle is the angle between the stator current space vector and the rotor d-axis, that is, the projection angle of the stator current vector on the q-axis. In motor control, this angle is also called the phase lead angle, control angle or current lead angle.

[0129] In the embodiment of the present application, the motor speed of the permanent magnet synchronous motor tends to 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle, which means that: the second direct-axis reference current and the second quadrature-axis reference current are reconstructed based on the target reference current angle, and the permanent magnet torque calculated according to the second direct-axis reference current and the second quadrature-axis reference current according to the above formula (5) and the reluctance torque calculated according to the above formula (6) are the same in magnitude and opposite in direction.

[0130] Optionally, an initial reference current angle is determined based on the inverse of the first straight-axis reference current and the first quadrature-axis reference current; a current compensation angle is determined based on the difference between the motor speed and the target speed, and the target speed is 0; and the sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle.

[0131] Exemplarily, the initial reference current angle is determined based on the inverse of the first straight-axis reference current and the first quadrature-axis reference current, as shown in the following formula (7).

[0132]

[0133] Among them, I qref Represents the first quadrature-axis reference current, I dref represents the first straight axis reference current. γ represents the initial reference current angle.

[0134] Exemplarily, the current compensation angle is obtained by adaptive adjustment. For example, when the motor speed is a positive speed (e.g., clockwise rotation), the current compensation angle is adjusted to obtain a new current compensation angle, so that the direct-axis reference current obtained by reconstruction based on the new current compensation angle is reduced, and the quadrature-axis reference current obtained by reconstruction based on the new current compensation angle is increased, thereby reducing the amplitude of the permanent magnet torque, increasing the amplitude of the magnetic resistance torque, making the output torque less than 0, and then reducing the motor speed so that the motor speed tends to 0. When the motor speed tends to 0, the current compensation angle is adjusted so that the output torque tends to 0, so that the motor speed is stabilized at a state close to 0. For another example, when the motor speed is negative (for example, counterclockwise rotation), the current compensation angle is adjusted to obtain a new current compensation angle, so that the direct-axis reference current reconstructed based on the new current compensation angle increases, and the quadrature-axis reference current reconstructed based on the new current compensation angle decreases, thereby increasing the amplitude of the permanent magnet torque and reducing the amplitude of the reluctance torque, so that the output torque is greater than 0, and then reducing the motor speed so that the motor speed tends to 0. When the motor speed tends to 0, the current compensation angle is adjusted so that the output torque tends to 0, so that the motor speed is stabilized at a state close to 0.

[0135] Optionally, a proportional-integral control algorithm is used to adaptively adjust the current compensation angle. In the embodiment of the present application, the purpose of adjusting the current compensation angle is to dynamically adjust the direct-axis reference current and the quadrature-axis reference current through the current compensation angle, so that the permanent magnet torque and the reluctance torque output by the permanent magnet synchronous motor are equal in magnitude and opposite in direction, so that the motor speed of the permanent magnet synchronous motor is equal to 0, and the permanent magnet synchronous motor reaches a stalled state under the condition that the current amplitude of the permanent magnet synchronous motor remains unchanged.

[0136] Among them, the proportional integral control algorithm is used to adjust the output control amount according to the difference between the actual value of the feedback signal and the target value of the reference signal, so that the actual value of the feedback signal is approximately equal to the target value of the reference signal. The actual value of the feedback signal in the embodiment of the present application is the actual motor speed, the target value of the reference signal is the target speed, the target speed is 0, and the output control amount is the current compensation angle. That is, the purpose of the proportional integral control algorithm is to control the motor speed to 0. The input of the proportional integral control algorithm is the motor speed and the target speed, and the output value is the current compensation angle. The target reference current angle is determined by the initial reference current angle and the current compensation angle, and the second direct axis reference current and the second quadrature axis reference current are reconstructed using the target reference current angle. If the motor speed is a positive speed (that is, the motor speed is greater than the target speed), the current compensation angle is adjusted to increase the second direct axis reference current and reduce the second quadrature axis reference current, thereby reducing the size of the motor's output torque, and then reducing the motor speed, until the output torque tends to 0 and the speed tends to 0. If the motor speed is negative (that is, the motor speed is less than the target speed), the current compensation angle is adjusted to reduce the second direct-axis reference current and increase the second quadrature-axis reference current, thereby reducing the output torque of the motor and then reducing the motor speed until the output torque approaches 0 and the speed approaches 0.

[0137] Optionally, the current compensation angle is not less than a first angle and not greater than a second angle, the first angle is equal to the negative of the initial reference current angle, and the second angle is equal to the difference between 90 degrees and the initial reference current angle.

[0138] Taking the first direct-axis reference current and the first quadrature-axis reference current working in the second quadrant as an example, in order to ensure that the second direct-axis reference current and the second quadrature-axis reference current work in the first quadrant, the current compensation angle needs to be limited. The limiting condition of the current compensation angle is as shown in the following formula (8).

[0139]

[0140] Among them, γ comp represents the current compensation angle, and γ represents the initial reference current angle.

[0141] 3032. Determine a second direct-axis reference current and a second quadrature-axis reference current based on the amplitude of the first reference current and the target reference current angle, and determine the second direct-axis reference current and the second quadrature-axis reference current as the second reference current.

[0142] Exemplarily, the amplitude of the first reference current is determined as shown in the following formula (9).

[0143]

[0144] Among them, I amp Represents the amplitude of the first reference current, I qref Represents the first quadrature-axis reference current, I dref Represents the first straight-axis reference current.

[0145] Exemplarily, the second direct-axis reference current and the second quadrature-axis reference current are determined as shown in the following formula (10).

[0146]

[0147] Among them, I drefnew Represents the second direct-axis reference current, I qrefnew Represents the second quadrature-axis reference current, I amp represents the amplitude of the first reference current, γ represents the initial reference current angle, and γ comp Represents the current compensation angle, γ+γ comp Indicates the target reference current angle.

[0148] In a possible implementation, when the current of the permanent magnet synchronous motor is equal to the second reference current, the sum of the permanent magnet torque and the reluctance torque of the permanent magnet synchronous motor is equal to 0, and the permanent magnet torque and the reluctance torque are equal in magnitude and opposite in direction.

[0149] Figure 4 is a flow chart of a current reconstruction method provided in an embodiment of the present application, such as Figure 4 As shown, a reference current table is queried according to the stall torque, bus voltage, and motor speed to obtain a first direct-axis reference current and a first quadrature-axis reference current, based on the first direct-axis reference current and the first quadrature-axis reference current, the amplitude of the first reference current and the initial reference current angle are calculated, the current compensation angle is calculated based on the motor speed, the sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle, and based on the target reference current angle, the components of the first reference current on the direct axis and the quadrature axis are reconstructed to obtain a second direct-axis reference current and a second quadrature-axis reference current.

[0150] 304. Based on the current of the permanent magnet synchronous motor and the second reference current, adjust the AC voltage of the permanent magnet synchronous motor so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current.

[0151] The current of the permanent magnet synchronous motor is the actual current, and the second reference current is the expected current.

[0152] In one possible implementation, a proportional-integral control algorithm is used to determine a direct-axis reference voltage and a quadrature-axis reference voltage based on the current of the permanent magnet synchronous motor and a second reference current; a Park inverse transform is used to transform the direct-axis reference voltage and the quadrature-axis reference voltage into an α-axis reference voltage and a β-axis reference voltage; a three-phase duty cycle is generated based on the α-axis reference voltage and the β-axis reference voltage; and according to the three-phase duty cycle, the bus voltage is transformed into an AC voltage of the permanent magnet synchronous motor so that the current of the adjusted permanent magnet synchronous motor approaches the second reference current.

[0153] Among them, the proportional-integral control algorithm is used to adjust the output control amount according to the difference between the actual value of the feedback signal and the target value of the reference signal, so that the actual value of the feedback signal is approximately equal to the target value of the reference signal. The actual value of the feedback signal in the embodiment of the present application is the actual current, the target value of the reference signal is the second reference current, and the output control amount is the AC voltage of the permanent magnet synchronous motor. That is, the purpose of the proportional-integral control algorithm is to control the current of the permanent magnet synchronous motor to the second reference current. The input of the proportional-integral control algorithm is the current of the permanent magnet synchronous motor and the second reference current, and the output value is the direct-axis reference voltage and the quadrature-axis reference voltage.

[0154] Optionally, a process of using Park inverse transformation to transform the direct-axis reference voltage and the quadrature-axis reference voltage into the α-axis reference voltage and the β-axis reference voltage is shown in the above formula (3), which will not be described in detail here.

[0155] In a possible implementation, when the current of the permanent magnet synchronous motor is equal to the second reference current, the sum of the permanent magnet torque and the reluctance torque of the permanent magnet synchronous motor is equal to 0, and the permanent magnet torque and the reluctance torque are equal in magnitude and opposite in direction.

[0156] Figure 5 is a flow chart of another motor control method provided in an embodiment of the present application. Figure 5 As shown, in Figure 1 On this basis, the method of obtaining the reference current is improved. Figure 5 In the above method, after obtaining the first straight-axis reference current and the first quadrature-axis reference current by querying the table, Figure 4According to the current reconstruction method in the invention, the first direct-axis reference current and the first quadrature-axis reference current are reconstructed to obtain the second direct-axis reference current and the second quadrature-axis reference current, and then the AC voltage of the permanent magnet synchronous motor is adjusted according to the difference between the second direct-axis reference current and the second quadrature-axis reference current and the actual direct-axis reference current and the quadrature-axis reference current of the permanent magnet synchronous motor, so that the current amplitude of the adjusted permanent magnet synchronous motor is equal to the current amplitude required to achieve the stall torque, and the speed of the permanent magnet synchronous motor tends to 0.

[0157] 305. When it is detected that the motor speed of the permanent magnet synchronous motor is not greater than the preset speed, a stall test is performed on the permanent magnet synchronous motor. The motor speed of the permanent magnet synchronous motor is not greater than the preset speed, indicating that the permanent magnet synchronous motor is currently in a stall state.

[0158] If the motor speed of the permanent magnet synchronous motor is not greater than the preset speed, it can be considered that the permanent magnet synchronous motor is currently in a stalled state. In this case, the permanent magnet synchronous motor can be subjected to a stalled test. The stalled test of the permanent magnet synchronous motor is to test whether the temperature of the permanent magnet synchronous motor and the power module exceeds the allowable normal operating range under high torque conditions such as peak torque or 0.7 times the peak torque, while maintaining a water flow rate of 8L / min and a water temperature of 65°C. The test time is generally no more than 30s.

[0159] Among them, the rotor heat capacity of the permanent magnet synchronous motor is much larger than the stator heat capacity. During the test time, the motor rotor temperature rise is negligible relative to the stator temperature rise. Therefore, the stall test motor mainly assesses whether the stator temperature exceeds the normal operating temperature threshold allowed by the motor. The stator temperature rise when the motor is stalled is determined by the motor loss. In the stalled state, the motor loss is copper loss, and the copper loss calculation formula is Q = I 2 Rt, where I represents the stator current, R represents the stator resistance, and t represents the time. Therefore, the stator temperature rise is fixed during the test time in the stalled state. Since the motor stalled test time is no more than 30s, the stator temperature after the temperature rise under this condition will not exceed the normal operating temperature range, so the motor overtemperature fault will not occur.

[0160] The power module used to control the AC voltage of the permanent magnet synchronous motor will also heat up in the stalled state. The time for the junction temperature of the power module to reach thermal equilibrium is generally within 3s. The junction temperature of the power module is determined by the conduction loss and switching loss of the power module. Under the conditions of fixed vector control bus voltage, three-phase AC voltage and switching frequency, the conduction loss and switching loss are fixed. Therefore, the goal of the stalled rotor test is to detect whether the junction temperature of the power module exceeds the normal operating temperature range under the conditions of fixed bus voltage, phase current and switching frequency.

[0161] An embodiment of the present application provides a motor stall test method, wherein a first reference current is the current required when the output torque of the permanent magnet synchronous motor reaches the stall torque. While keeping the amplitude of the first reference current unchanged, a second reference current is obtained by reconstructing the components of the first reference current on the direct axis and the quadrature axis. Then, according to the difference between the current current of the permanent magnet synchronous motor and the second reference current, the AC voltage of the permanent magnet synchronous motor is adjusted so that the current of the permanent magnet synchronous motor tends to the second reference current. At this time, the speed of the permanent magnet synchronous motor tends to 0 and the current amplitude of the permanent magnet synchronous motor is equal to the current amplitude required to reach the stall torque, thereby ensuring that the permanent magnet synchronous motor is in a stall state without applying external force to the permanent magnet synchronous motor, and then performing a stall test on the permanent magnet synchronous motor. There is no need to lock the output shaft of the permanent magnet synchronous motor, and the permanent magnet synchronous motor is stalled by the internal logic of the permanent magnet synchronous motor, which is conducive to reducing the cost of the stall test and improving the convenience of the stall test on the permanent magnet synchronous motor.

[0162] Figure 6 is a schematic diagram of the structure of a motor stall test device provided in an embodiment of the present application. Figure 6 , the device comprises:

[0163] The acquisition module 601 is used to acquire the current and motor speed of the permanent magnet synchronous motor;

[0164] An acquisition module 602 is used to acquire a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque;

[0165] A reconstruction module 603 is used to keep the amplitude of the first reference current unchanged, and reconstruct the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain a second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor tends to 0;

[0166] An adjustment module 604 is used to adjust the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current, so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current;

[0167] The test module 605 is used to perform a stall test on the permanent magnet synchronous motor when it is detected that the motor speed of the permanent magnet synchronous motor is not greater than a preset speed. The motor speed of the permanent magnet synchronous motor is not greater than the preset speed, indicating that the permanent magnet synchronous motor is currently in a stall state.

[0168] The motor stall test device provided in the embodiment of the present application comprises a first reference current which is the current required when the output torque of the permanent magnet synchronous motor reaches the stall torque. While keeping the amplitude of the first reference current unchanged, the second reference current is obtained by reconstructing the components of the first reference current on the direct axis and the quadrature axis. Then, according to the difference between the current current of the permanent magnet synchronous motor and the second reference current, the AC voltage of the permanent magnet synchronous motor is adjusted so that the current of the permanent magnet synchronous motor tends to the second reference current. At this time, the speed of the permanent magnet synchronous motor tends to 0 and the current amplitude of the permanent magnet synchronous motor is equal to the current amplitude required to reach the stall torque. This ensures that the permanent magnet synchronous motor is in a stall state without applying external force to the permanent magnet synchronous motor, and then performs a stall test on the permanent magnet synchronous motor. There is no need to lock the output shaft of the permanent magnet synchronous motor. The permanent magnet synchronous motor is stalled by the internal logic of the permanent magnet synchronous motor, which is conducive to reducing the cost of the stall test and improving the convenience of the stall test on the permanent magnet synchronous motor.

[0169] Optionally, the acquisition module 601 is used to:

[0170] Collect the three-phase AC current of the permanent magnet synchronous motor;

[0171] Clark transformation is used to transform the three-phase AC current into α-axis current and β-axis current;

[0172] Park transformation is used to transform the α-axis current and the β-axis current into the direct-axis current and the quadrature-axis current based on the rotor position of the permanent magnet synchronous motor.

[0173] Optionally, the acquisition module 602 is used to:

[0174] Obtain the stall torque and bus voltage of the permanent magnet synchronous motor;

[0175] In the reference current table, query the reference current corresponding to the stall torque, bus voltage and motor speed, and determine the queried reference current as the first reference current;

[0176] The reference current table stores reference currents corresponding to any torque, any bus voltage, and any click speed.

[0177] Optionally, the adjustment module 604 is used to:

[0178] A proportional-integral control algorithm is adopted to determine a direct-axis reference voltage and a quadrature-axis reference voltage based on the current of the permanent magnet synchronous motor and a second reference current;

[0179] Using Park inverse transformation, the direct-axis reference voltage and the quadrature-axis reference voltage are transformed into an α-axis reference voltage and a β-axis reference voltage;

[0180] Generate three-phase duty ratios based on the α-axis reference voltage and the β-axis reference voltage;

[0181] According to the three-phase duty cycle, the bus voltage is converted into the AC voltage of the permanent magnet synchronous motor, so that the current of the permanent magnet synchronous motor tends to the second reference current after adjustment.

[0182] Optionally, the first reference current includes a first straight-axis reference current and a first quadrature-axis reference current; the reconstruction module 603 is used to:

[0183] Determine a target reference current angle based on the inverse of the first straight-axis reference current, the first quadrature-axis reference current and the motor speed, so that the motor speed of the permanent magnet synchronous motor tends to 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle;

[0184] Based on the amplitude of the first reference current and the target reference current angle, a second direct-axis reference current and a second quadrature-axis reference current are determined, and the second direct-axis reference current and the second quadrature-axis reference current are determined as the second reference current.

[0185] Optionally, the reconstruction module 603 is used to:

[0186] determining an initial reference current angle based on the inverse of the first straight-axis reference current and the first quadrature-axis reference current;

[0187] Based on the difference between the motor speed and the target speed, the current compensation angle is determined, and the target speed is 0;

[0188] The sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle.

[0189] Optionally, the current compensation angle is not less than a first angle and not greater than a second angle, the first angle is equal to the negative of the initial reference current angle, and the second angle is equal to the difference between 90 degrees and the initial reference current angle.

[0190] It should be noted that the motor stall test device provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the electronic device is divided into different functional modules to complete all or part of the functions described above. In addition, the motor stall test device provided in the above embodiment and the motor stall test method embodiment belong to the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0191] In some embodiments, the embodiments of the present application also provide a vehicle electric drive system, which includes a permanent magnet synchronous motor, a motor controller and a memory, wherein at least one computer program is stored in the memory, and at least one computer program is run by the motor controller to implement the motor stall test method as in the above embodiments.

[0192] In some embodiments, a computer-readable storage medium is also provided, in which a computer program is stored, and when the computer program is executed, the steps of the motor stall test method in the above embodiment are implemented. For example, the computer-readable storage medium can be a ROM (Read-Only Memory), a RAM (Random Access Memory), a CD-ROM (Compact Disc Read-Only Memory), a magnetic tape, a floppy disk, and an optical data storage device. It is worth noting that the computer-readable storage medium mentioned in the embodiment of the present application can be a non-volatile storage medium, in other words, it can be a non-transient storage medium.

[0193] It should be understood that all or part of the steps to implement the above embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. The computer instructions can be stored in the above-mentioned computer readable storage medium.

[0194] That is, in some embodiments, a computer program product including instructions is also provided, which, when executed on a computer, enables the computer to execute the steps of the vehicle testing method described above.

[0195] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in the embodiments of the present application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data need to comply with relevant laws, regulations and standards of relevant countries and regions.

[0196] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A motor stall test method, characterized in that: The method comprises: Collect the current and motor speed of the permanent magnet synchronous motor; Acquire a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque; Keeping the amplitude of the first reference current unchanged, reconstructing the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain a second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor tends to 0; Based on the current of the permanent magnet synchronous motor and the second reference current, adjusting the AC voltage of the permanent magnet synchronous motor so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current; When it is detected that the motor speed of the permanent magnet synchronous motor is not greater than the preset speed, a stall test is performed on the permanent magnet synchronous motor. The motor speed of the permanent magnet synchronous motor being not greater than the preset speed indicates that the permanent magnet synchronous motor is currently in a stall state.

2. The motor stall test method according to claim 1, characterized in that: The collecting of the current of the permanent magnet synchronous motor comprises: Collecting the three-phase alternating current of the permanent magnet synchronous motor; The three-phase alternating current is transformed into an α-axis current and a β-axis current by using Clark transformation; The α-axis current and the β-axis current are transformed into a direct-axis current and a quadrature-axis current based on the rotor position of the permanent magnet synchronous motor by using Park transformation.

3. The motor stall test method according to claim 1, characterized in that: The obtaining of a first reference current of the permanent magnet synchronous motor comprises: Acquiring the stall torque and the bus voltage of the permanent magnet synchronous motor; In the reference current table, query the reference current corresponding to the stall torque, the bus voltage and the motor speed, and determine the queried reference current as the first reference current; The reference current table stores reference currents corresponding to any torque, any bus voltage and any click speed.

4. The motor stall test method according to claim 1, characterized in that: The step of adjusting the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current so that the current of the permanent magnet synchronous motor after adjustment approaches the second reference current includes: Adopting a proportional-integral control algorithm, based on the current of the permanent magnet synchronous motor and the second reference current, determining a direct-axis reference voltage and a quadrature-axis reference voltage; Using Park inverse transformation to transform the direct-axis reference voltage and the quadrature-axis reference voltage into an α-axis reference voltage and a β-axis reference voltage; generating a three-phase duty cycle based on the α-axis reference voltage and the β-axis reference voltage; According to the three-phase duty cycle, the bus voltage is converted into an AC voltage of the permanent magnet synchronous motor, so that the current of the permanent magnet synchronous motor tends to the second reference current after adjustment.

5. The motor stall test method according to claim 1, characterized in that: The first reference current includes a first direct-axis reference current and a first quadrature-axis reference current; the amplitude of the first reference current is kept unchanged, and based on the motor speed, the components of the first reference current on the direct axis and the quadrature axis are reconstructed to obtain the second reference current, including: Determine a target reference current angle based on the inverse of the first direct-axis reference current, the first quadrature-axis reference current, and the motor speed, so that the motor speed of the permanent magnet synchronous motor tends to 0 after the permanent magnet synchronous motor is controlled based on the target reference current angle; Based on the amplitude of the first reference current and the target reference current angle, a second direct-axis reference current and a second quadrature-axis reference current are determined, and the second direct-axis reference current and the second quadrature-axis reference current are determined as the second reference current.

6. The motor stall test method according to claim 5, characterized in that: The step of determining a target reference current angle based on the inverse of the first direct-axis reference current, the first quadrature-axis reference current, and the motor speed comprises: determining an initial reference current angle based on the inverse of the first direct-axis reference current and the first quadrature-axis reference current; Determining a current compensation angle based on a difference between the motor speed and a target speed, wherein the target speed is 0; The sum of the initial reference current angle and the current compensation angle is determined as the target reference current angle.

7. The motor stall test method according to claim 6, characterized in that: The current compensation angle is not less than a first angle and not greater than a second angle, the first angle is equal to the negative of the initial reference current angle, and the second angle is equal to the difference between 90 degrees and the initial reference current angle.

8. The motor stall test method according to claim 1, characterized in that: When the current of the permanent magnet synchronous motor is equal to the second reference current, the sum of the permanent magnet torque and the reluctance torque of the permanent magnet synchronous motor is equal to 0, and the permanent magnet torque and the reluctance torque are equal in magnitude and opposite in direction.

9. A motor stall test device, characterized in that: The device comprises: An acquisition module is used to acquire the current and motor speed of the permanent magnet synchronous motor; An acquisition module, used for acquiring a first reference current of the permanent magnet synchronous motor, where the first reference current is a current required when the output torque of the permanent magnet synchronous motor reaches a stall torque; a reconstruction module, configured to keep the amplitude of the first reference current unchanged, and reconstruct the components of the first reference current on the direct axis and the quadrature axis based on the motor speed to obtain a second reference current, so that when the current of the permanent magnet synchronous motor is equal to the second reference current, the motor speed of the permanent magnet synchronous motor approaches 0; an adjustment module, configured to adjust the AC voltage of the permanent magnet synchronous motor based on the current of the permanent magnet synchronous motor and the second reference current, so that the current of the permanent magnet synchronous motor after adjustment tends to the second reference current; The test module is used to perform a stall test on the permanent magnet synchronous motor when it is detected that the motor speed of the permanent magnet synchronous motor is not greater than a preset speed. The motor speed of the permanent magnet synchronous motor is not greater than the preset speed, indicating that the permanent magnet synchronous motor is currently in a stall state.

10. A vehicle electric drive system, characterized in that: The vehicle electric drive system includes a permanent magnet synchronous motor, a motor controller and a memory, wherein the memory stores at least one computer program, and the at least one computer program is executed by the motor controller to implement the motor stall test method as described in any one of claims 1 to 8.

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