Motor controller, power assembly and electric vehicle

Abstract

The invention provides a motor controller, a power assembly and an electric vehicle, and is applied to the technical field of electric vehicles, the motor controller comprises three phases of bridge arm circuits and a bridge arm driving circuit, and the two ends of a bridge arm of each phase of bridge arm circuit in the three phases of bridge arm circuits are used for receiving power supplied by a power battery of the vehicle. And the bridge arm midpoint of each phase of bridge arm circuit in the three-phase bridge arm circuit is used for outputting one phase of alternating current to a driving motor of the vehicle. The bridge arm driving circuit can control the three-phase bridge arm circuit to output three-phase alternating current to drive the driving motor to drive the vehicle to run, and controls the three-phase bridge arm circuit to enter a protection state after receiving an active short-circuit protection signal in the process that the driving motor drives the vehicle to run. In addition, after the three-phase bridge arm circuit enters one protection state for a first duration, the bridge arm driving circuit can also control the three-phase bridge arm circuit to enter another protection state or maintain the protection state, so that the active short-circuit protection transient current can be suppressed more quickly.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a motor controller, a powertrain and an electric vehicle. Background Art

[0002] The motor controller (MCU) is a component used to control the motor in new energy vehicles. The motor controller is also connected to the power battery and can convert the DC power provided by the power battery into the AC power required for the drive motor to work. The motor controller is generally equipped with a three-phase bridge arm circuit. By controlling the on and off of the switch tube on each phase of the bridge arm current in the three-phase bridge arm circuit, the DC power can be converted into AC power. Among the various types of drive motors, permanent magnet synchronous motors have attracted widespread attention and favor from electric vehicle manufacturers due to their advantages such as high efficiency, high power density and high reliability. Among them, when the vehicle is running at high speed, the permanent magnet synchronous motor needs to operate in a weak magnetic condition to actively weaken the motor back electromotive force to increase the operating speed range. If the drive system fails at this time, the protection scheme of directly shutting down the drive signal will cause all the switch tubes of the three-phase bridge arm circuit to be shut down, which will cause chain problems such as overcharging of busbar capacitors, overvoltage breakdown of power devices, and torque loss of control. In some related technologies, active short-circuit control can be used to control the switch tubes in the three-phase bridge arm circuit to avoid the above problems. However, this solution will generate extremely high transient current, which may cause potential risks such as overcurrent damage to power devices and demagnetization of motor permanent magnets. Therefore, it is urgent to provide a solution to solve the above problems. Summary of the invention

[0003] Embodiments of the present application provide a motor controller, a powertrain, and an electric vehicle to achieve faster suppression of transient current in an active short-circuit protection state of a three-phase bridge arm circuit.

[0004] In order to solve the above problems, the embodiments of the present application provide the following technical solutions.

[0005] In a first aspect, a motor controller is provided, which includes a three-phase bridge arm circuit and a bridge arm drive circuit. The three-phase bridge arm circuit includes a three-phase upper bridge arm switch tube and a three-phase lower bridge arm switch tube. The two ends of the bridge arm of each phase of the three-phase bridge arm circuit are used to receive the power supply of the vehicle's power battery, and the midpoint of the bridge arm of each phase of the three-phase bridge arm circuit is used to output a single-phase alternating current to the vehicle's drive motor. Wherein, the drive motor is a permanent magnet synchronous motor. The bridge arm drive circuit is used to control the three-phase bridge arm circuit to output three-phase alternating current to drive the drive motor to drive the vehicle, and after receiving an active short-circuit protection signal during the process of the drive motor driving the vehicle, control the three-phase bridge arm circuit to enter one of the two protection states. After the three-phase bridge arm circuit enters the first duration of the above-mentioned one protection state, the bridge arm drive circuit is also used to control the three-phase bridge arm circuit to enter another protection state of the above-mentioned two protection states or maintain the above-mentioned one protection state. Wherein, the above-mentioned two protection states include an active short-circuit protection state and an uncontrolled rectification protection state. The active short-circuit protection state is that one bridge arm drive circuit controls the three-phase upper bridge arm switch tube to remain on at the same time and the three-phase lower bridge arm switch tube to remain off at the same time, or one bridge arm drive circuit controls the three-phase upper bridge arm switch tube to remain off at the same time and the three-phase lower bridge arm switch tube to remain on at the same time. The uncontrolled rectification protection state is that one bridge arm drive circuit controls the three-phase upper bridge arm switch tube and the three-phase lower bridge arm switch tube to remain off at the same time.

[0006] In the above manner, after receiving an active short-circuit protection signal during the process of the driving motor driving the vehicle, the above-mentioned bridge arm driving circuit can first control the three-phase bridge arm circuit to enter a protection state, and then control the three-phase bridge arm circuit to enter another protection state or maintain the above-mentioned protection state after a first period of time. Based on this, the bridge arm driving circuit can drive the three-phase bridge arm circuit to switch between the active short-circuit protection state and the uncontrolled rectification protection state and control the duration of each protection state, thereby avoiding the three-phase bridge arm circuit from being in the active short-circuit protection state or the uncontrolled rectification protection state for a long time, thereby suppressing the transient current of the active short-circuit protection state, and preventing the three-phase upper bridge arm switch tube or the three-phase lower bridge arm switch tube in the three-phase bridge arm circuit from being damaged by overcurrent.

[0007] In one embodiment, the bridge arm driving circuit can also control the three-phase bridge arm circuit to enter the above-mentioned one protection state after controlling the three-phase bridge arm circuit to enter the above-mentioned another protection state for a second time period. In the above manner, the bridge arm driving circuit can control the three-phase bridge arm circuit to repeatedly switch between the active short-circuit protection state and the uncontrolled rectification protection state, which can better suppress the active short-circuit protection transient current of the three-phase bridge arm circuit.

[0008] In one embodiment, the difference between the first duration and the second duration is less than or equal to a preset value, and the preset value is less than or equal to one third of the first duration or the second duration. In the above manner, the duration of the active short-circuit protection state and the uncontrolled rectification protection state can be more uniform, thereby better protecting the device while suppressing the transient current in the active short-circuit protection state.

[0009] In one embodiment, the bridge arm drive circuit can control the three-phase bridge arm circuit to enter an active short-circuit protection state after receiving an active short-circuit protection signal during the process of driving the motor to drive the vehicle at a speed greater than or equal to a first speed, and control the three-phase bridge arm circuit to enter an uncontrolled rectification protection state after the three-phase bridge arm circuit enters the active short-circuit protection state for a first time period. In the above manner, the bridge arm drive circuit can control the three-phase bridge arm circuit to switch between the active short-circuit protection state and the uncontrolled rectification protection state when the vehicle is traveling at a high speed and active short-circuit protection is required, thereby suppressing the transient current in the active short-circuit protection state.

[0010] In one embodiment, the above-mentioned bridge arm driving circuit can further control the three-phase bridge arm circuit to maintain the uncontrolled rectification protection state or enter the active short-circuit protection state after controlling the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for a second time period. In the above manner, the bridge arm driving circuit can choose to maintain the uncontrolled rectification protection state or enter the active short-circuit protection state according to the state of the drive motor after the three-phase bridge arm circuit enters the uncontrolled rectification protection state for the second time period, so as to adjust the control mode of the three-phase bridge arm circuit according to actual conditions.

[0011] In one embodiment, the bridge arm drive circuit can also control the three-phase bridge arm circuit to enter an active short circuit protection state after receiving an active short circuit protection signal during the process of driving the vehicle with the driving motor driving the vehicle at a speed less than or equal to the second speed. After the three-phase bridge arm circuit enters the active short circuit protection state for a first duration, the three-phase bridge arm circuit is controlled to maintain the active short circuit protection state. The second speed is less than the first speed. In the above manner, the bridge arm drive circuit can also control the three-phase bridge arm circuit to be in an active short circuit protection state when the vehicle is running at a low speed and active short circuit protection is required.

[0012] In one embodiment, the bridge arm driving circuit is further used to control the three-phase bridge arm circuit to maintain the above-mentioned one protection state or enter the above-mentioned other protection state according to the d-axis component of the stator current of the drive motor after controlling the three-phase bridge arm circuit to enter the above-mentioned one protection state for a first time period. In the above manner, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the active short-circuit protection state or enter the uncontrolled rectification protection state according to the d-axis component of the stator current of the drive motor, thereby better suppressing the active short-circuit protection transient current.

[0013] In one embodiment, after controlling the three-phase bridge arm circuit to enter the active short-circuit protection state for a first duration, the bridge arm drive circuit is further used to: in response to the d-axis component of the stator current of the drive motor being less than the first current value, control the three-phase bridge arm circuit to enter the uncontrolled rectification protection state. In the above manner, when the d-axis component of the stator current of the drive motor is very small, the influence on the switch tube of the three-phase bridge arm circuit and the winding of the drive motor is very small. Therefore, all the switch tubes of the three-phase bridge arm circuit can be turned off.

[0014] In one embodiment, the first current value is less than or equal to the motor characteristic current value of the drive motor -ψ f / L d , ψ f is the permanent magnet flux of the drive motor, L d is the d-axis inductance of the drive motor.

[0015] In one embodiment, after controlling the three-phase bridge arm circuit to enter an uncontrolled rectification protection state for a first period of time, the above-mentioned bridge arm drive circuit is also used to: in response to the d-axis component of the stator current of the driving motor being greater than a second current value, control the three-phase bridge arm circuit to enter an active short-circuit protection state.

[0016] In one embodiment, after controlling the three-phase bridge arm circuit to enter an active short-circuit protection state for a first period of time, the above-mentioned bridge arm drive circuit is also used to: in response to the d-axis component of the stator current of the driving motor being greater than the first current value and less than the second current value, control the three-phase bridge arm circuit to maintain an active short-circuit protection state.

[0017] In one embodiment, the second current value is greater than the motor characteristic current value -ψ f / L d , ψ f is the permanent magnet flux of the drive motor, L d is the d-axis inductance of the drive motor.

[0018] In one implementation, the d-axis component and the q-axis component of the stator current of the drive motor are calculated according to the following formula:

[0019]

[0020] Among them, i d with i q are the d-axis component and q-axis component of the stator current of the drive motor, i a 、i b with i c are the collected A-phase stator current, B-phase stator current and C-phase stator current of the drive motor, θ e is the collected electrical angle of the motor rotor of the drive motor.

[0021] In a second aspect, a power assembly is provided, the power assembly comprising a drive motor and a motor controller in any possible implementation of the first aspect. The motor controller is used to output three-phase current to control the drive motor.

[0022] In a third aspect, an electric vehicle is provided, which includes a power battery and a powertrain as described in the second aspect above, wherein the power battery is used to supply power to a motor controller in the powertrain.

[0023] Regarding the technical principles and beneficial effects of the second and third aspects, please refer to the relevant description of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a topological structure of an electric vehicle provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of the structure of a powertrain provided in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of a motor controller provided in an embodiment of the present application;

[0027] Figure 4 A relationship diagram between the three-phase winding current and the dq-axis current of a drive motor provided in an embodiment of the present application;

[0028] Figure 5 A control flow diagram of a three-phase bridge arm circuit provided in an embodiment of the present application Figure 1 ;

[0029] Figure 6 A control flow diagram of a three-phase bridge arm circuit provided in an embodiment of the present application Figure 2 ;

[0030] Figure 7 A control flow diagram of a three-phase bridge arm circuit provided in an embodiment of the present application Figure 3 ;

[0031] Figure 8 A control flow diagram of a three-phase bridge arm circuit provided in an embodiment of the present application Figure 4 ;

[0032] Fig. 9 A relationship diagram between three-phase winding current and dq-axis current of another drive motor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0034] It should be noted that the words "in one embodiment" or "exemplary" in this application are used to indicate examples, illustrations or descriptions. Any embodiment or design described in this application as "in one embodiment" or "exemplary" should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "in one embodiment" or "exemplary" is intended to present related concepts in a specific way.

[0035] The present application is described in detail below with reference to the accompanying drawings and embodiments:

[0036] like Figure 1 As shown, an electric vehicle 100 in the field of new energy vehicles generally includes a powertrain 300 and a power battery 200. The power battery 200 is used to power the powertrain 300. A plurality of powertrains 300 are generally arranged in the electric vehicle 100, and each powertrain 300 is powered by the power battery 200. In order to facilitate the control of the powertrain 300, each powertrain 300 is also connected to a vehicle controller 400 in the electric vehicle 100. A control signal can be sent to a motor controller in the powertrain 300 through the vehicle controller 400. The motor controller can receive the control signal and control the torque required for the drive motor to output so as to drive the vehicle. As shown in FIG. Figure 2 As shown, the power assembly 300 includes a motor controller 310 and a drive motor 320. The motor controller 310 is used to convert the direct current of the power battery 200 into three-phase alternating current to drive the drive motor 320 to output the required torque.

[0037] Among them, Figure 3 As shown, the motor controller 310 includes a three-phase bridge arm circuit 311, a bridge arm drive circuit 312 and a controller 313. Among them, the two ends of the bridge arm of each phase of the three-phase bridge arm circuit 311 are used to receive the power supply of the vehicle's power battery 200, and the midpoint of the bridge arm of each phase of the three-phase bridge arm circuit 311 is used to output a single-phase AC power to the vehicle's drive motor to drive the vehicle's drive motor 320. The above-mentioned three-phase bridge arm circuit 311 includes a three-phase upper bridge arm switch tube and a three-phase lower bridge arm switch tube. Among them, each phase of the bridge arm circuit includes an upper bridge arm switch tube and a lower bridge arm switch tube, and an upper bridge arm switch tube and a lower bridge arm switch tube of each phase of the bridge arm circuit are used to be turned on and off according to a drive signal output by a bridge arm drive circuit 312, respectively.

[0038] For example, Figure 3As shown, the three-phase bridge arm circuit 311 may include an A-phase bridge arm circuit, a B-phase bridge arm circuit, and a C-phase bridge arm circuit. The A-phase bridge arm circuit includes an upper bridge arm switch tube Q1 and a lower bridge arm switch tube Q2, the first pole of the upper bridge arm switch tube Q1 is connected to the positive pole of the power battery 200 through the positive DC bus INP, the second pole of the upper bridge arm switch tube Q1 and the first pole of the lower bridge arm switch tube Q2 are connected to the A-phase winding of the drive motor 320 through the bridge arm midpoint a of the A-phase bridge arm circuit, and the second pole of the lower bridge arm switch tube Q2 is connected to the negative pole of the power battery 200 through the negative DC bus INN. The B-phase bridge arm circuit includes an upper bridge arm switch tube Q3 and a lower bridge arm switch tube Q4, the first pole of the upper bridge arm switch tube Q3 is connected to the positive pole of the power battery 200 through the positive DC bus INP, the second pole of the upper bridge arm switch tube Q3 and the first pole of the lower bridge arm switch tube Q4 are connected to the B-phase winding of the drive motor 320 through the bridge arm midpoint b of the B-phase bridge arm circuit, and the second pole of the lower bridge arm switch tube Q4 is connected to the negative pole of the power battery 200 through the negative DC bus INN. The C-phase bridge arm circuit includes an upper bridge arm switch tube Q5 and a lower bridge arm switch tube Q6, the first pole of the upper bridge arm switch tube Q5 is connected to the positive pole of the power battery 200 through the positive DC bus INP, the second pole of the upper bridge arm switch tube Q5 and the first pole of the lower bridge arm switch tube Q6 are connected to the C-phase winding of the drive motor 320 through the bridge arm midpoint c of the C-phase bridge arm circuit, and the second pole of the lower bridge arm switch tube Q6 is connected to the negative pole of the power battery 200 through the negative DC bus INN.

[0039] The bridge arm driving circuit 312 can output a driving signal to each of the upper bridge arm switch tubes (Q1, Q3 and Q5) and each of the lower bridge arm switch tubes (Q2, Q4 and Q6) through the control signal sent by the controller 313 to control the conduction and shutdown of Q1~Q6, thereby outputting the required torque of the three-phase AC drive motor 320 to the three-phase winding of the drive motor 320 to drive the vehicle to move.

[0040] In the motor controller 310 shown in the embodiment of the present application, each phase bridge arm circuit includes not only an upper bridge arm switch tube or a lower bridge arm switch tube, but also a detection module ( Figure 3 ), such as a temperature detection module, a current detection module, a voltage detection module, a short circuit detection module and an open circuit detection module.

[0041] In electric vehicles, the drive motor 320 usually uses a permanent magnet synchronous motor. The drive system includes a drive motor 320, a drive shaft and wheels, wherein the torque output by the drive motor 320 drives the wheels to rotate through the drive shaft, thereby driving the vehicle to travel. When the vehicle is traveling at high speed, the permanent magnet synchronous motor needs to operate in a weak magnetic condition, thereby actively weakening the back electromotive force of the drive motor to increase the operating speed range. If a fault occurs in the drive system including the drive motor 320, the drive shaft and the wheels at this time, the protection scheme of directly shutting down the drive signal will cause all the switch tubes in the three-phase bridge arm circuit 311 to be shut down, thereby causing chain problems such as overcharging of the bus capacitor, overvoltage breakdown of the power device, and torque loss of control. In some related technologies, an active short-circuit method can be used to control the three-phase bridge arm circuit 311 to avoid the above problems. However, if Figure 4 As shown, the A-phase winding current i of the drive motor 320 using the above solution is a , B phase winding current i b The C phase winding current i c The peak values ​​of the three-phase winding currents are very high and take a long time to stabilize. At this time, the d-axis component i of the stator current of the drive motor 320 is d and the q-axis component i q。 The peak value is also very high and takes a long time to stabilize, resulting in extremely high transient currents, with potential risks such as overcurrent damage to power devices and demagnetization of motor permanent magnets.

[0042] In order to solve the above problems, the present application embodiment provides a motor controller 310, which can be selected from Figure 3 The structure in the embodiment of the present application is not described in detail here. In the embodiment provided in the present application, the bridge arm drive circuit 312 in the motor controller 310 can control the three-phase bridge arm circuit 311 to output three-phase alternating current to drive the drive motor to drive the vehicle. In addition, the above-mentioned bridge arm drive circuit 312 can also control the three-phase bridge arm circuit to repeatedly switch between the active short-circuit protection state and the uncontrolled rectification state after receiving an active short-circuit protection signal during the driving process of the vehicle, and in the switching process between the active short-circuit protection state and the uncontrolled rectification state, the duration of the active short-circuit protection state and the duration of the uncontrolled rectification state are relatively uniform, so as to protect the devices in the three-phase bridge arm circuit while suppressing the transient current of the active short-circuit protection state faster.

[0043] In the above process, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit to enter one of the active short circuit protection state and the uncontrolled rectification state after receiving an active short circuit protection signal during the process of driving the motor to drive the vehicle. Then, after the three-phase bridge arm circuit enters the above protection state for the first time, the three-phase bridge arm circuit is controlled to enter the other protection state of the active short circuit protection state and the uncontrolled rectification state or maintain the above protection state. Among them, the active short circuit protection state is that a bridge arm driving circuit controls the three-phase upper bridge arm switch tube to remain turned on at the same time and the three-phase lower bridge arm switch tube to remain turned off at the same time, or a bridge arm driving circuit controls the three-phase upper bridge arm switch tube to remain turned off at the same time and the three-phase lower bridge arm switch tube to remain turned on at the same time, and the uncontrolled rectification protection state is that a bridge arm driving circuit controls the three-phase upper bridge arm switch tube and the three-phase lower bridge arm switch tube to remain turned off at the same time.

[0044] Further, the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to switch repeatedly between the active short circuit protection state and the uncontrolled rectification state, and different switching modes can be adopted according to the speed of the vehicle. Wherein, when the vehicle is traveling at high speed, the transient current in the active short circuit protection state is high, and the bridge arm driving circuit 312 can control the three-phase bridge arm circuit 311 to switch repeatedly between the active short circuit protection state and the uncontrolled rectification state when the vehicle is traveling at high speed, so as to suppress the transient current in the active short circuit protection state while avoiding damage to the switch tube in the three-phase bridge arm circuit or causing the permanent magnet of the motor to demagnetize. In addition, when the vehicle is traveling at a low speed, the transient current in the active short circuit protection state is small, and the bridge arm driving circuit 312 can directly control the three-phase bridge arm circuit 311 to enter the active short circuit protection state, and after the three-phase bridge arm circuit enters the first duration of the active short circuit protection state, control the three-phase bridge arm circuit to maintain the active short circuit protection state, so as to consume the back electromotive force of the drive motor 320 through the switch tube in the three-phase bridge arm circuit 311 and the three-phase winding of the drive motor.

[0045] In one embodiment, the bridge arm drive circuit 312 may control the three-phase bridge arm circuit 311 to enter an active short-circuit protection state after receiving an active short-circuit protection signal during a process in which the vehicle is traveling at a speed greater than or equal to a first speed. Then, the bridge arm drive circuit 312 may control the three-phase bridge arm circuit to enter an uncontrolled rectification protection state after the three-phase bridge arm circuit enters the active short-circuit protection state for a first duration. Next, the bridge arm drive circuit 312 may control the three-phase bridge arm circuit to maintain an uncontrolled rectification protection state or enter an active short-circuit protection state after the three-phase bridge arm circuit enters the uncontrolled rectification protection state for a second duration, and this cycle is repeated until the stator current of the drive motor tends to stabilize and the uncontrolled rectification protection state is maintained.

[0046] In addition, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit to enter the active short circuit protection state after receiving an active short circuit protection signal during the process in which the vehicle is traveling at a speed less than or equal to the second speed. Then, after the three-phase bridge arm circuit enters the active short circuit protection state for a first time period, the three-phase bridge arm circuit is controlled to maintain the active short circuit protection state. The second speed is less than the first speed.

[0047] Further, on the basis of the above scheme, after the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to enter a protection state for the first duration, it can also control the three-phase bridge arm circuit 311 to maintain the above protection state or enter another protection state according to the d-axis component of the stator current of the drive motor 320. Among them, after the three-phase bridge arm circuit 311 enters the active short-circuit protection state for the first duration, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit to enter the uncontrolled rectification protection state when the d-axis component of the stator current of the drive motor 320 is less than the first current value. The bridge arm driving circuit 312 can also control the three-phase bridge arm circuit to enter the active short-circuit protection state when the d-axis component of the stator current of the drive motor 320 is greater than the second current value. In addition, the bridge arm driving circuit 312 can also drive the d-axis component of the stator current of the motor 320 to be greater than the first current value and less than the second current value, and control the three-phase bridge arm circuit 311 to maintain the active short-circuit protection state.

[0048] Through the above method, it can be ensured that the current value of the three-phase bridge arm circuit 311 changes within the range between the first current value and the second current value when switching between the active short-circuit protection state and the uncontrolled rectification state, and the transient current of the active short-circuit protection state is further suppressed, thereby suppressing the transient current of the active short-circuit protection state more quickly.

[0049] In one embodiment, if Figure 5 As shown, after receiving an active short-circuit protection signal during the process of the drive motor 320 driving the vehicle, the bridge arm drive circuit 312 can control the switching process of the active short-circuit protection state and the uncontrolled rectification state only according to the duration of the active short-circuit protection state and the uncontrolled rectification state. The specific contents are as follows.

[0050] S501: After the bridge arm driving circuit receives an active short-circuit protection signal during the process of driving the vehicle with the driving motor, the three-phase bridge arm circuit is controlled to enter an active short-circuit protection state.

[0051] The power battery 200 and the drive motor 320 can be isolated by active short circuit, so that the back electromotive force of the drive motor 320 is consumed by the winding of the drive motor 320 to generate a corresponding braking torque, thereby ensuring driving safety.

[0052] In one embodiment, if the drive motor 320 has a short circuit fault, an overspeed problem, or a wheel of the vehicle is out of control, the controller 313 can send an active short circuit protection signal to the bridge arm drive circuit 312. After receiving the active short circuit protection signal, the bridge arm drive circuit 312 can first control the three-phase bridge arm circuit 311 to enter the active short circuit protection state. The above-mentioned active short circuit protection state is that the bridge arm drive circuit 312 controls the three-phase upper bridge arm switch tube (i.e., Figure 3 Q1, Q3 and Q5 in the circuit are kept on at the same time, and the three-phase lower bridge arm switch tube (i.e. Figure 3 The Q2, Q4 and Q6 in the three-phase bridge arm circuit 311 are kept off at the same time, or the bridge arm driving circuit 312 controls the three-phase upper bridge arm switch tubes (i.e. Figure 3 Q1, Q3 and Q5 in the circuit breaker are kept off and the three-phase lower bridge arm switch tube (i.e. Figure 5 Q2, Q4 and Q6 in the circuit remain on at the same time.

[0053] In the above implementation process, the short circuit fault of the drive motor 320 can be detected by the corresponding fault detection circuit, and the embodiments of the present application are not described in detail here. Wheel loss of control includes sensor failure, brake failure, slippage and other faults of the wheel, and the above faults can also be detected by the detection circuit set on the wheel, and the embodiments of the present application are not described in detail here.

[0054] In one embodiment, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit 311 to continue to execute S505 when the drive motor 320 is in a stable state, or control the three-phase bridge arm circuit 311 to continue to execute S502 when the drive motor 320 is not in a stable state. When the d-axis component and the q-axis component of the stator current of the drive motor 320 satisfy the following relationship, it can be determined that the drive motor 320 is in a stable state:

[0055]

[0056] Among them, ψ f is the permanent magnet flux linkage of the drive motor 320, L d is the d-axis inductance of the drive motor 320, L q is the q-axis inductance of the drive motor 320, δ is a positive constant, i d with i q are the d-axis component and the q-axis component of the stator current of the drive motor 320 .

[0057] In the above implementation process, if the d-axis component and the q-axis component of the stator current of the drive motor 320 do not satisfy the above relationship, the drive motor 320 is not in a steady state.

[0058] S502: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state.

[0059] Among them, the above-mentioned uncontrolled rectification protection state is that a bridge arm driving circuit 312 controls the three-phase upper bridge arm switch tube and the three-phase lower bridge arm switch tube to remain turned off at the same time. When the three-phase bridge arm circuit 311 enters the uncontrolled rectification protection state, it can prevent the upper bridge arm switch tube or the lower bridge arm switch tube of each phase bridge arm circuit from being turned on for a long time when the vehicle is running at high speed, causing the temperature of the device to be too high, thereby damaging the switch tube or causing the permanent magnet of the motor to demagnetize.

[0060] S503: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for a second time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the active short circuit protection state.

[0061] The difference between the first duration and the second duration is less than or equal to a preset value, and the preset value is less than or equal to one third of the first duration or the second duration.

[0062] In one embodiment, the difference between the first duration and the second duration can be set according to the first duration. Assuming that the first duration is 15 milliseconds (ms), the second duration can be any duration between 10ms and 20ms.

[0063] In one embodiment, the difference between the first duration and the second duration can be set according to the second duration. Assuming that the second duration is 21 milliseconds (ms), the first duration can be any duration between 14ms and 28ms.

[0064] Furthermore, in order to make the current more stable during the switching process between the active short-circuit protection state and the uncontrolled rectification protection state, the above-mentioned preset value can be set to one third of the smaller value of the first time length and the second time length, thereby reducing the difference between the first time length and the second time length, so as to more stably suppress the short-circuit current of the three-phase bridge arm circuit 311.

[0065] In an embodiment, in order to make the first duration and the second duration more uniform, the preset value may also be less than or equal to one quarter or one sixth of the first duration or the second duration.

[0066] S504: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the active short circuit protection state for a third time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state.

[0067] In one embodiment, the third duration and the first duration may be the same. Based on this, when the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to switch between the active short circuit protection state and the uncontrolled rectification state, the duration of the active short circuit protection state can be more conveniently controlled.

[0068] In one embodiment, the third duration mentioned above may also be different from the first duration mentioned above. Based on this, in the process where the bridge arm drive circuit 312 controls the three-phase bridge arm circuit 311 to switch between the active short-circuit protection state and the uncontrolled rectification state, the duration of each active short-circuit protection state can be adjusted according to actual needs. Similarly, the duration of each uncontrolled rectification state may be the same or different, and the embodiments of the present application will not be described in detail here.

[0069] S505: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the active short-circuit protection state.

[0070] In one embodiment, after the three-phase bridge arm circuit 311 enters the active short-circuit protection state for the first period of time, the bridge arm drive circuit 312 can also control the three-phase bridge arm circuit 311 to maintain the active short-circuit protection state, so as to increase the duration of the active short-circuit protection state according to actual needs, thereby better consuming the back electromotive force of the drive motor 320.

[0071] In one embodiment, after the bridge arm driving circuit 312 completes S502 , it may also selectively execute S506 .

[0072] S506: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for the second time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the uncontrolled rectification protection state.

[0073] Through the above method, the time duration for the three-phase bridge arm circuit 311 to enter the uncontrolled rectification protection state can be extended according to actual needs, so as to reduce the temperature of the device.

[0074] In one embodiment, the bridge arm driving circuit 312 can also control the switching process between the active short circuit protection state and the uncontrolled rectification state of the three-phase bridge arm circuit according to the speed of the vehicle. Figure 6 As shown, if the drive motor 320 has a short circuit fault, an overspeed problem, or a wheel of the vehicle is out of control, S601 to S606 can be executed when the speed at which the drive motor 320 drives the vehicle is greater than or equal to the first speed.

[0075] S601: After the bridge arm driving circuit receives an active short-circuit protection signal during the process of driving the vehicle driven by the driving motor at a speed greater than or equal to a first speed, the three-phase bridge arm circuit is controlled to enter an active short-circuit protection state.

[0076] In the above implementation process, the speed at which the drive motor 320 drives the vehicle is greater than or equal to the first speed, which can indicate that the wheels are running at a high speed. At this time, the drive motor 320 operates in a weak magnetic condition, and the three-phase bridge arm circuit 311 can first isolate the power battery and the drive motor 320 by actively short-circuiting, thereby consuming the back electromotive force of the drive motor 320 through the winding of the drive motor 320 to generate a corresponding braking torque.

[0077] In one embodiment, the above-mentioned first speed can be selectively set to 60km / h. Based on this, when the speed of the vehicle driven by the drive motor 320 is greater than or equal to 60km / h, the bridge arm drive circuit 312 controls the three-phase bridge arm circuit 311 to enter the active short-circuit protection state after receiving an active short-circuit protection signal. After executing S601, the bridge arm drive circuit 312 can continue to execute S602 or execute S605. In one embodiment, the bridge arm drive circuit 312 can control the three-phase bridge arm circuit 311 to continue to execute S605 when the drive motor 320 is in a stable state, or control the three-phase bridge arm circuit 311 to continue to execute S602 when the drive motor 320 is not in a stable state. Among them, the stable state of the drive motor 320 can be judged with reference to the above-mentioned method, and the embodiment of the present application is not repeated here. In addition, the above-mentioned first speed is only an exemplary implementation method given in the embodiment of the present application, and the actual value of the first speed can be set according to the actual high-speed driving division condition.

[0078] S602: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state.

[0079] After the three-phase bridge arm circuit 311 enters the active short circuit protection state for the first time, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit 311 to enter the uncontrolled rectification protection state. Based on this, it can be avoided that the upper bridge arm switch tube or the lower bridge arm switch tube of each phase bridge arm circuit is turned on for a long time, causing the temperature of the device to be too high, thereby damaging the switch tube or causing the permanent magnet of the motor to demagnetize.

[0080] In one embodiment, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit 311 to enter the uncontrolled rectification protection state after the three-phase bridge arm circuit 311 enters the active short circuit protection state for a first time period. By controlling the three-phase bridge arm circuit 311 to enter the uncontrolled rectification protection state, the temperature of the switch tube and the winding of the drive motor 320 can be reduced, thereby preventing the device temperature from being too high and damaging the temperature of the switch tube and the winding of the drive motor 320.

[0081] S603: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for a second time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the active short circuit protection state.

[0082] The difference between the first duration and the second duration is less than or equal to a preset value, and the preset value is less than or equal to one third of the first duration or the second duration.

[0083] In one embodiment, the difference between the first duration and the second duration can be set according to the first duration. Assuming that the first duration is 12 milliseconds (ms), the second duration can be any duration between 8 ms and 16 ms.

[0084] In one embodiment, the difference between the first duration and the second duration can be set according to the second duration. Assuming that the second duration is 18 milliseconds (ms), the first duration can be any duration between 12ms and 24ms.

[0085] Furthermore, in order to make the current of the process switch tube more stable during the switching process between the active short-circuit protection state and the uncontrolled rectification protection state, the above-mentioned preset value can be set to one third of the smaller value of the first time length and the second time length, thereby reducing the difference between the first time length and the second time length, so as to more stably suppress the short-circuit current of the three-phase bridge arm circuit 311.

[0086] In the above implementation process, the above-mentioned first duration and second duration are only an exemplary implementation method given in the embodiment of the present application, and the setting method of the first duration and the second duration can also be adjusted according to actual needs. In addition, the above-mentioned first duration and second duration can also be adaptively adjusted according to the switch tube actually used in the three-phase bridge arm circuit, the DC bus capacitor actually used between the positive DC bus INP and the negative DC bus INN, and the bus voltage output from the power battery to both ends of the three-phase bridge arm circuit.

[0087] S604: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the active short circuit protection state for a third time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state.

[0088] In one embodiment, the third duration and the first duration may be the same. Based on this, when the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to switch between the active short circuit protection state and the uncontrolled rectification state, the duration of the active short circuit protection state can be more conveniently controlled.

[0089] In one embodiment, the third duration mentioned above may also be different from the first duration mentioned above. Based on this, in the process where the bridge arm drive circuit 312 controls the three-phase bridge arm circuit 311 to switch between the active short-circuit protection state and the uncontrolled rectification state, the duration of each active short-circuit protection state can be adjusted according to actual needs. Similarly, the duration of each uncontrolled rectification state may be the same or different, and the embodiments of the present application will not be described in detail here.

[0090] S605: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the active short-circuit protection state.

[0091] In one embodiment, after the three-phase bridge arm circuit 311 enters the active short-circuit protection state for the first period of time, the bridge arm drive circuit 312 can also control the three-phase bridge arm circuit 311 to maintain the active short-circuit protection state, so as to increase the duration of the active short-circuit protection state according to actual needs, thereby better consuming the back electromotive force of the drive motor 320.

[0092] In one embodiment, after the bridge arm driving circuit 312 completes S602 , it may also selectively execute S606 .

[0093] S606: After the bridge arm driving circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for the second time period, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the uncontrolled rectification protection state.

[0094] Through the above method, the time duration for the three-phase bridge arm circuit 311 to enter the uncontrolled rectification protection state can be extended according to actual needs, so as to reduce the temperature of the device.

[0095] In one embodiment, if Figure 7 As shown, if the drive motor 320 has a short circuit fault, an overspeed problem, or a wheel of the vehicle is out of control, S701 to S702 can be executed when the speed at which the drive motor 320 drives the vehicle is less than or equal to the second speed. The second speed is less than the first speed.

[0096] S701: After the bridge arm driving circuit receives an active short-circuit protection signal during the process of driving the motor to drive the vehicle to travel at a speed less than or equal to a second speed, the three-phase bridge arm circuit is controlled to enter an active short-circuit protection state.

[0097] When the vehicle is traveling at a speed less than or equal to the second speed, even if the wheel is out of control, the back electromotive force generated by the drive motor 320 is very small, and the back electromotive force has little effect on the upper bridge arm switch tube and the lower bridge arm switch tube in each phase bridge arm circuit. At this time, the bridge arm drive circuit 312 can also control the three-phase bridge arm circuit 311 to enter the active short-circuit protection state, thereby consuming the back electromotive force of the drive motor 320 through the winding of the drive motor 320 to generate a corresponding braking torque.

[0098] In one embodiment, the second speed can be selectively set to 10 km / h. When the vehicle travels at a speed less than or equal to 10 km / h, the bridge arm driving circuit 312 can control the three-phase bridge arm circuit to enter an active short circuit protection state.

[0099] It can be understood that the above-mentioned second speed is only an exemplary implementation given in the embodiment of the present application, and the actual value of the second speed can also be set according to actual needs.

[0100] S702: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the three-phase bridge arm circuit is controlled to maintain the active short-circuit protection state.

[0101] After the three-phase bridge arm circuit 311 enters the active short-circuit protection state for the first period of time, the bridge arm driving circuit 312 can also control the three-phase bridge arm circuit 311 to maintain the active short-circuit protection state, so as to more fully consume the back electromotive force of the drive motor 320 through the winding of the drive motor 320 until the wheels stop moving or the vehicle speed is lower than the preset critical value.

[0102] In one embodiment, the above critical value may be set to 5 km / h. Of course, the critical value is only an exemplary implementation given in the embodiment of the present application, and the above critical value may also be adjusted according to actual needs.

[0103] In one embodiment, after the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to enter a protection state for a first time period, the process in which the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 to maintain a protection state or enter another protection state according to the d-axis component of the stator current of the driving motor 320 can be performed according to Figure 8 The specific contents are as follows.

[0104] S801: After the bridge arm driving circuit receives an active short-circuit protection signal during the process of driving the vehicle with the driving motor, the three-phase bridge arm circuit is controlled to enter an active short-circuit protection state.

[0105] In one embodiment, the controller 313 can send an active short circuit protection signal to the bridge arm driving circuit 312 when the speed of the driving motor 320 driving the vehicle is greater than or equal to the first speed. After the bridge arm driving circuit 312 receives the active short circuit protection signal, it can control the three-phase bridge arm circuit 311 to enter the active short circuit protection state.

[0106] S802: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm drive circuit controls the three-phase bridge arm circuit to enter the uncontrolled rectification protection state in response to the d-axis component of the stator current of the drive motor being less than the first current value.

[0107] When the d-axis component of the stator current of the drive motor 320 is less than the first current value, the back electromotive force of the drive motor 320 is low, and the back electromotive force has little effect on the upper bridge arm switch tube and the lower bridge arm switch tube in each phase bridge arm circuit. At this time, the three-phase bridge arm circuit 311 is controlled to enter the uncontrolled rectification protection state.

[0108] In the above implementation process, the first current value is less than or equal to the motor characteristic current value -ψ f / L d , ψ f is the permanent magnet flux linkage of the drive motor 320, L d is the d-axis inductance of the driving motor 320 .

[0109] Furthermore, the d-axis component and the q-axis component of the stator current of the drive motor 320 are calculated according to the following formula:

[0110]

[0111] Among them, i d with i q are the d-axis component and the q-axis component of the stator current of the drive motor 320, i a 、i b with i c are the collected A-phase stator current, B-phase stator current and C-phase stator current of the drive motor 320, θ e is the collected electrical angle of the motor rotor of the drive motor 320 .

[0112] S803: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm driving circuit controls the three-phase bridge arm circuit to maintain the active short-circuit protection state in response to the d-axis component of the stator current of the driving motor being greater than the second current value.

[0113] When the d-axis component of the stator current of the drive motor 320 is greater than the second current value, the back electromotive force of the drive motor 320 is high. At this time, it is necessary to control the three-phase bridge arm circuit 311 to enter an active short-circuit protection state through the bridge arm drive circuit 312, so as to consume the back electromotive force of the drive motor 320 through the winding of the drive motor 320.

[0114] S804: After the three-phase bridge arm circuit enters the active short-circuit protection state for a first period of time, the bridge arm drive circuit controls the three-phase bridge arm circuit to maintain the active short-circuit protection state in response to the d-axis component of the stator current of the drive motor being greater than the first current value and less than the second current value.

[0115] When the d-axis component of the stator current of the drive motor 320 is greater than the first current value and less than the second current value, the back electromotive force of the drive motor 320 can be consumed through the winding of the drive motor 320 by controlling the three-phase bridge arm circuit 311 to maintain an active short-circuit protection state.

[0116] In the above implementation process, the second current value is greater than the motor characteristic current value -ψ of the drive motor 320. f / L d , ψ f is the permanent magnet flux linkage of the drive motor 320, L d is the d-axis inductance of the driving motor 320 .

[0117] In the above implementation process, if the d-axis component of the stator current of the drive motor 320 does not meet the above conditions of S802 to S804, the bridge arm drive circuit 312 does not change the existing control method of the three-phase bridge arm circuit. For example, if the three-phase bridge arm circuit 311 is currently in an active short-circuit protection state, and the d-axis component of the stator current of the drive motor 320 does not meet the above conditions of S802 to S804, the three-phase bridge arm circuit 311 maintains the active short-circuit protection state. Similarly, if the three-phase bridge arm circuit 311 is currently in an uncontrolled rectification protection state, and the d-axis component of the stator current of the drive motor 320 does not meet the above conditions of S802 to S804, the three-phase bridge arm circuit 311 maintains the uncontrolled rectification protection state.

[0118] like Fig. 9 As shown, after the bridge arm driving circuit 312 controls the three-phase bridge arm circuit 311 through the above-mentioned embodiments, Figure 4 In the same scenario, the three-phase winding current of the drive motor 320 (including the A-phase winding current i a , B phase winding current i b The C phase winding current i c ) is significantly reduced and can be stabilized more quickly. The stator current of the drive motor 320 (including the d-axis current i d and q-axis current i q) is also significantly reduced, and can be stabilized more quickly. Therefore, the motor controller provided in the embodiment of the present application can effectively suppress the active short-circuit protection transient current.

[0119] In summary, the embodiments of the present application provide a motor controller, a powertrain, and an electric vehicle, which are applied to the field of electric vehicle technology. The motor controller includes a three-phase bridge arm circuit and a bridge arm drive circuit. The two ends of the bridge arm of each phase of the bridge arm circuit in the three-phase bridge arm circuit are used to receive power from the vehicle's power battery, and the midpoint of the bridge arm of each phase of the bridge arm circuit in the three-phase bridge arm circuit is used to output a single-phase alternating current to the vehicle's drive motor. The bridge arm drive circuit can control the three-phase bridge arm circuit to output three-phase alternating current to drive the drive motor to drive the vehicle, and after receiving an active short-circuit protection signal during the process of the drive motor driving the vehicle, control the three-phase bridge arm circuit to enter an active short-circuit protection state. After the three-phase bridge arm circuit enters the active short-circuit protection state for the first time, the bridge arm drive circuit can also control the three-phase bridge arm circuit to enter an uncontrolled rectification protection state or maintain an active short-circuit protection state. Based on this, the bridge arm driving circuit can drive the three-phase bridge arm circuit to switch between the active short-circuit protection state and the uncontrolled rectification protection state according to the implementation situation, so as to avoid the three-phase bridge arm circuit being in the active short-circuit protection state for a long time, thereby suppressing the active short-circuit protection transient current more quickly and preventing the three-phase upper bridge arm switch tube or the three-phase lower bridge arm switch tube in the three-phase bridge arm circuit from being damaged by overcurrent.

[0120] In several embodiments provided in the present application, each functional module may be integrated into one device, or each module may exist physically separately, or two or more modules may be integrated into one device.

[0121] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A motor controller, characterized in that: The motor controller includes a three-phase bridge arm circuit and a bridge arm drive circuit, the three-phase bridge arm circuit includes a three-phase upper bridge arm switch tube and a three-phase lower bridge arm switch tube, the two ends of the bridge arm of each phase of the three-phase bridge arm circuit are used to receive power from the power battery of the vehicle, the midpoint of the bridge arm of each phase of the three-phase bridge arm circuit is used to output a single-phase alternating current to the drive motor of the vehicle, the drive motor is a permanent magnet synchronous motor, and the one bridge arm drive circuit is used to: Controlling the three-phase bridge arm circuit to output three-phase alternating current to drive the drive motor to drive the vehicle to travel; After receiving an active short-circuit protection signal during the process of the driving motor driving the vehicle, controlling the three-phase bridge arm circuit to enter one of two protection states; After the three-phase bridge arm circuit enters the one protection state for a first time period, controlling the three-phase bridge arm circuit to enter another protection state of the two protection states or maintaining the one protection state; Among them, the two protection states include an active short-circuit protection state and an uncontrolled rectification protection state. The active short-circuit protection state is that the one bridge arm drive circuit controls the three-phase upper bridge arm switch tube to remain turned on at the same time and the three-phase lower bridge arm switch tube to remain turned off at the same time, or the one bridge arm drive circuit controls the three-phase upper bridge arm switch tube to remain turned off at the same time and the three-phase lower bridge arm switch tube to remain turned on at the same time. The uncontrolled rectification protection state is that the one bridge arm drive circuit controls the three-phase upper bridge arm switch tube and the three-phase lower bridge arm switch tube to remain turned off at the same time.

2. The motor controller according to claim 1, characterized in that: The one bridge arm driving circuit is also used for: After controlling the three-phase bridge arm circuit to enter the other protection state for a second time period, controlling the three-phase bridge arm circuit to enter the one protection state.

3. The motor controller according to claim 2, characterized in that: A difference between the first duration and the second duration is less than or equal to a preset value, and the preset value is less than or equal to one third of the first duration or the second duration.

4. The motor controller according to any one of claims 1 to 3, characterized in that: The one bridge arm driving circuit is further used for: After receiving the active short-circuit protection signal during the process in which the driving motor drives the vehicle to travel at a speed greater than or equal to a first speed, controlling the three-phase bridge arm circuit to enter the active short-circuit protection state; After the three-phase bridge arm circuit enters the active short-circuit protection state for the first time period, the three-phase bridge arm circuit is controlled to enter the uncontrolled rectification protection state.

5. The motor controller according to claim 4, characterized in that: The one bridge arm driving circuit is further used for: After controlling the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for a second time period, controlling the three-phase bridge arm circuit to maintain the uncontrolled rectification protection state or to enter the active short-circuit protection state.

6. The motor controller according to any one of claims 1 to 5, characterized in that: The one bridge arm driving circuit is also used for: After receiving the active short-circuit protection signal in the process in which the driving motor drives the vehicle to travel at a speed less than or equal to a second speed, controlling the three-phase bridge arm circuit to enter the active short-circuit protection state; After the three-phase bridge arm circuit enters the active short-circuit protection state for the first time period, controlling the three-phase bridge arm circuit to maintain the active short-circuit protection state; Wherein, the second speed is lower than the first speed.

7. The motor controller according to any one of claims 1 to 6, characterized in that: The one bridge arm driving circuit is also used for: After controlling the three-phase bridge arm circuit to enter the one protection state for a first period of time, the three-phase bridge arm circuit is controlled to maintain the one protection state or enter the other protection state according to the d-axis component of the stator current of the drive motor.

8. The motor controller according to claim 7, characterized in that: After controlling the three-phase bridge arm circuit to enter the active short circuit protection state for the first time period, the one bridge arm driving circuit is further used for: In response to the d-axis component of the stator current of the drive motor being less than a first current value, the three-phase bridge arm circuit is controlled to enter the uncontrolled rectification protection state.

9. The motor controller according to claim 8, characterized in that: The first current value is less than or equal to the motor characteristic current value of the drive motor - ψ f / L d , ψ f is the permanent magnet flux of the drive motor, L d is the d-axis inductance of the drive motor.

10. The motor controller according to any one of claims 7 to 9, characterized in that: After controlling the three-phase bridge arm circuit to enter the uncontrolled rectification protection state for the first time period, the one bridge arm driving circuit is further used for: In response to the d-axis component of the stator current of the drive motor being greater than a second current value, the three-phase bridge arm circuit is controlled to enter the active short-circuit protection state.

11. The motor controller according to claim 10, characterized in that: After controlling the three-phase bridge arm circuit to enter the active short-circuit protection state for the first time period, the one driving circuit is further used for: In response to the d-axis component of the stator current of the drive motor being greater than the first current value and less than the second current value, the three-phase bridge arm circuit is controlled to maintain the active short-circuit protection state.

12. The motor controller according to claim 10 or 11, characterized in that: The first current value is greater than the motor characteristic current value of the drive motor -ψ f / L d , ψ f is the permanent magnet flux of the drive motor, L d is the d-axis inductance of the drive motor.

13. The motor controller according to any one of claims 6 to 12, characterized in that: The d-axis component and the q-axis component of the stator current of the drive motor are calculated according to the following formula: Among them, i d with i q are the d-axis component and the q-axis component of the stator current of the drive motor, i a 、i b with i c are the collected A-phase stator current, B-phase stator current and C-phase stator current of the drive motor, θ e is the collected electrical angle of the motor rotor of the drive motor.

14. A powertrain, characterized in that: The powertrain includes a drive motor and a motor controller as described in any one of claims 1 to 13, wherein the motor controller is used to output three-phase current to control the drive motor.

15. An electric vehicle, characterized in that: The electric vehicle comprises a power battery and the powertrain as claimed in claim 14, wherein the power battery is used to supply power to the motor controller in the powertrain.

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