Three-phase active short-circuit protection system and method for electric vehicle motor controller

Abstract

The application discloses a three-phase active short-circuit protection system of an electric vehicle motor controller, when a main control chip fails, an FS control chip judges that a motor power module needs to enter an ASC mode, and outputs an enable signal to stop working of a first control power module and a driving power module, the main control chip is powered off due to the stop working of the first control power module, a primary side of a driving chip is powered off due to the stop working of the first control power module, a upper bridge arm driving signal generation module and a lower bridge arm driving signal generation module of a secondary side of the driving chip are powered off due to the stop working of the driving power module, and the FS control chip outputs upper bridge arm or lower bridge arm driving signals of a three-phase inverter bridge, the upper bridge arm or lower bridge arm driving signals control opening of upper bridge arm or lower bridge arm switch tubes in the three-phase inverter bridge of the motor power module. When the main control chip of the motor controller fails, the application realizes controlled parking of a permanent magnet synchronous motor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicle motor controller, in particular to a three-phase active short-circuit protection system and method for electric vehicle motor controller. BACKGROUND

[0002] In the selection of electric vehicle drive motor, permanent magnet synchronous motor is widely used due to its high power density, small size, high efficiency and other advantages. However, the rotor of the permanent magnet synchronous motor is a permanent magnet. If the motor controller needs to be stopped urgently due to failure and the IGBT (Insulated Gate Bipolar Transistor) is closed, the frequency of the motor stator will directly decrease to 0 Hz, and the rotor permanent magnet will quickly cut the stator coil, so that the motor works in a power generation feedback working condition, thereby generating a huge braking torque.

[0003] The uncontrolled huge braking torque will cause the vehicle to decelerate sharply, which is easy to cause rear-end collision and bumping of passengers in the vehicle, and other accidents. Moreover, the vehicle decelerates too fast, so that the driver cannot slide the vehicle to a safe area for parking, which is also easy to cause traffic accidents. Moreover, if the reverse electromotive force is greater than the battery bus voltage, the battery pack will be damaged.

[0004] Therefore, the motor controller generally adopts a three-phase active short-circuit protection method (ASC) to avoid the above problems when emergency shutdown is needed.

[0005] The ASC action is to simultaneously turn on the three switch tubes of the upper bridge arm of the motor controller three-phase inverter bridge, and turn off the three switch tubes of the lower bridge arm; or simultaneously turn on the three switch tubes of the lower bridge arm, and turn off the three switch tubes of the upper bridge arm. Figure 2 、 Figure 3 Generally, the latter method is used to realize the ASC action. In this way, the three-phase output voltage vector of the motor controller is zero vector, the direct current end and the alternating current end circuit no longer form a loop, and the line current of the motor circulates in the motor controller three-phase inverter bridge and the motor, and will not be fed back to the high-voltage battery pack to damage the battery.

[0006] Reasonable use of ASC mode can produce the following advantages:

[0007] 1. When the vehicle is out of control, the braking torque generated by the ASC action is much smaller than the braking torque generated by the direct stop of the motor controller, so that the driver has sufficient time to slide the car to a safe area;

[0008] 2. When the power battery fails, the implementation of ASC can isolate the motor, the motor controller and the power battery, and ensure the safety of the high-voltage part of the vehicle.

[0009] 3. When the motor speed is too high or abnormal during the driving of the vehicle, the ASC can avoid the damage of the high reverse electromotive force to the power battery, bus capacitor or other elements.

[0010] 4. When the power module has a fault during the inverter process of the motor controller, the ASC can avoid the damage of the uncontrolled rectification to the power battery or other elements.

[0011] When the motor controller performs ASC action due to internal or external failure, if the failure is not the main control chip failure, the ASC action is controlled by the main control chip. If the failure is the main control chip failure, the ASC action is controlled by the FS (Functional Safety) control chip, but the control loop cannot be the same as the main control chip, otherwise the main control chip failure will be transferred to the FS control chip. In order to cooperate with the FS control chip to realize the control of the drive chip, the drive chip needs to select a product with ASC function pin.

[0012] If the ASC action is completed by the main control chip, the main control chip outputs 6-way PWM signals to the 6-way drive chip, the 3-way PWM signals of the upper bridge arm are low, and the 3-way PWM signals of the lower bridge arm are high, so as to realize that the drive chip simultaneously turns on the three switch tubes of the lower bridge arm and turns off the three switch tubes of the upper bridge arm.

[0013] If the ASC action is completed by the FS control chip, the ASC pins of the 3-way drive chip of the upper bridge arm are low, and the ASC pins of the 3-way drive chip of the lower bridge arm are high, so as to realize that the drive chip simultaneously turns on the three switch tubes of the lower bridge arm and turns off the three switch tubes of the upper bridge arm.

[0014] However, the existing ASC protection circuit method also has several shortcomings:

[0015] 1. When the drive chip fails, the motor controller cannot enter the ASC mode;

[0016] 2. It is necessary to select a drive chip with ASC function, the circuit cost is high, and it is not easy to borrow the existing mature circuit;

[0017] 3. According to the ASC function characteristics of the drive chip, most of the ASC pins of the drive chip with ASC function are on the strong electric side of the drive chip, such as STGAP1AS of ST company, and a small part of the ASC pins of the drive chip are on the weak electric side and the strong electric side, such as drive chip UCC5870-Q1 Figure 4When the low-voltage side of the driver chip loses power, its ASC pin will become unusable. However, the high-voltage side of the driver chip, powered by an emergency backup power supply, will still have its ASC pin usable. Therefore, in practical applications, the ASC pin on the high-voltage side of the driver chip is mostly used. This necessitates the addition of six digital isolation devices to transmit the control signals from the FS control chip to the high-voltage side. Summary of the Invention

[0018] The purpose of this invention is to provide a three-phase active short-circuit protection system and method for electric vehicle motor controllers. When the main control chip of the motor controller fails, the invention enables the motor controller to enter ASC mode through the FS control chip and its circuit, thereby achieving controlled shutdown of the permanent magnet synchronous motor and protecting the power battery and high-voltage components in the electric vehicle.

[0019] To achieve this objective, the electric vehicle motor controller three-phase active short-circuit protection system designed in this invention includes a main control chip, a first control power supply module, a drive power supply module, a drive chip, a drive module, a motor power module, and an FS control chip. When the main control chip malfunctions, the FS control chip samples the motor bus voltage and three-phase current, and determines the required operating mode of the motor power module based on the results of the bus voltage and three-phase current sampling. When the determination result indicates that the motor power module needs to enter ASC mode, the FS control chip outputs an enable signal to enable the first control chip. When the power supply module and drive power supply module stop working, the main control chip loses power due to the first control power supply module stopping working, the primary side of the drive chip loses power due to the first control power supply module stopping working, and the secondary side upper bridge arm drive signal generation module and secondary side lower bridge arm drive signal generation module of the drive chip lose power due to the drive power supply module stopping working. The upper or lower bridge arm drive signal of the three-phase inverter bridge output by the FS control chip is used by the drive module to control the upper or lower bridge arm switch of the three-phase inverter bridge in the motor power module to turn on, and the motor controller enters ASC mode.

[0020] The beneficial effects of this invention are:

[0021] In ASC mode, the motor will suddenly generate a strong braking torque in the low-speed range (such as...). Figure 5 As shown), therefore, the motor controller needs to be switched from ASC mode to free stop mode after the motor back EMF is less than the bus voltage (as shown). Figure 6The FS control chip collects the bus voltage of the motor controller and the three-phase current of the motor. The current motor speed can be calculated by the frequency of the three-phase current. According to the speed and the back electromotive force coefficient of the motor, the current back electromotive force voltage of the motor can be calculated. When the back electromotive force voltage is greater than or equal to the bus voltage, the motor controller works in the ASC mode, preventing the motor energy from being fed back to the battery pack, and the motor outputs a slight braking torque; when the back electromotive force voltage is less than the bus voltage, the motor controller works in the shutdown mode, and all the switching tubes of the three-phase inverter bridge are in the off state. Since the antiparallel diodes of the three-phase inverter bridge are also in the off state at this time, the motor three-phase current is zero, the output torque is zero, and the motor is in free shutdown, and the motor energy cannot be fed back to the battery pack, so that the high voltage of the motor cannot damage the battery pack.

[0022] The application can still realize ASC action when the driving chip fails by increasing the redundant driving control circuit. Meanwhile, by controlling the enablement of each power supply circuit, the use of digital isolator devices can be reduced, and stronger functions can be realized under the condition of reducing the overall cost. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the application;

[0024] Figure 2 It is a schematic diagram of the principle of the three-phase inverter bridge and the motor.

[0025] Figure 3 It is a schematic diagram of the power module state in the ASC mode.

[0026] Figure 4 It is a schematic diagram of the driving chip UCC5870-Q1.

[0027] Figure 5 It is a schematic diagram of the relationship between the torque and the speed of the driving motor in the ASC mode.

[0028] Figure 6 It is a schematic diagram of the switching between the ASC mode and the free shutdown mode.

[0029] Figure 3 In the figure, all the bridge arms of the power module in the shutdown mode are closed, S1 is the U-phase upper bridge arm, S4 is the U-phase lower bridge arm; S2 is the V-phase upper bridge arm, S5 is the V-phase lower bridge arm; S3 is the W-phase upper bridge arm, and S6 is the W-phase lower bridge arm. VDC is the voltage output by the battery pack. Figure 3 In the left figure, all the three-phase upper bridge arms are closed, and all the three-phase lower bridge arms are opened in the ASC mode. In the right figure, all the three-phase upper bridge arms are opened, and all the three-phase lower bridge arms are closed in the ASC mode.

[0030] Wherein, 1-main control chip, 2-first control power module, 3-driving power module, 4-driving chip, 5-driving module, 6-motor power module, 7-FS control chip, 8-second control power module, 9-electric isolation device, 10-buffer, 11-backup power module. DETAILED DESCRIPTION

[0031] The application will be further described below in combination with the drawings and specific embodiments:

[0032] As Figure 1 shown in a kind of electric automobile motor controller three-phase active short-circuit protection system, it includes main control chip 1, first control power module 2, driving power module 3, driving chip 4, driving module 5, motor power module 6, FS control chip 7, when main control chip 1 fails, FS control chip 7 carries out bus voltage sampling and three-phase current sampling to motor, and according to the result of bus voltage sampling and three-phase current sampling, the working mode required for motor power module 6 is judged, when the result of judgment is that motor power module 6 needs to enter ASC mode, FS control chip 7 outputs enable signal to make first control power module 2 and driving power module 3 stop working, main control chip 1 is powered off due to first control power module 2 stops working, the PWM signal of main control chip 1 is pulled down to low level by external pull-down resistor (after the output of the PWM module of main control chip 1, since the existence of pull-down resistor, it is low level at this time), the primary side of driving chip 4 is powered off due to first control power module 2 stops working, the upper bridge arm drive signal generation module and the lower bridge arm drive signal generation module of the secondary side of driving chip 4 are powered off due to driving power module 3 stops working, the output of driving chip 4 becomes high resistance, the upper bridge arm or lower bridge arm drive signal (the lower bridge arm drive signal in this embodiment) of three-phase inverter bridge output by FS control chip 7, the upper bridge arm or lower bridge arm drive signal is controlled motor power module 6 three switching tubes (such as Figure 2 S4, S5 and S6 in it) in the upper bridge arm or lower bridge arm of three-phase inverter bridge of the opening (the lower bridge arm is opened in this embodiment, and the upper bridge arm is closed), motor controller enters ASC mode, after entering ASC mode, motor can output slight brake torque, so that the driver can have sufficient time to slide the car to the safe area when counter electromotive voltage is less than bus voltage, motor controller works in switching to shutdown mode, and motor is free to stop. Motor power module 6 is IGBT, for converting direct current voltage into frequency adjustable alternating current, by connecting or disconnecting control electrode to control the connection and shutdown between cathode and anode to realize the inversion between direct current and alternating current to power motor.

[0033] There are two methods to enter the ASC mode: the first is that the three upper bridge arms of the three phases are all closed, and the three lower bridge arms of the three phases are all turned on; the second is that the three upper bridge arms of the three phases are all turned on, and the three lower bridge arms of the three phases are all closed. Since the three-phase lower bridge arm 3 driving circuit shares the ground, only one primary side ASC signal is needed to control the three switch tubes of the lower bridge arm of the power module, and only one electrical isolation device is needed, so the first ASC mode is adopted in the embodiment. When an abnormal fault is found, the three switch tubes of the upper bridge arm of the motor power module 6 are closed, and the three switch tubes of the lower bridge arm of the motor power module 6 are opened.

[0034] When one or more of the six driving chips fail, the FS control chip can still take over the control of the three switch tubes of the lower bridge arm through the electrical isolation device, so that the motor controller enters the ASC mode. When the motor controller loses the 12V voltage source, the entire control system cannot work due to power failure, and the motor controller also needs to enter the ASC mode at this time. Since entering the ASC mode is only related to the FS control chip circuit and the three driving circuits of the lower bridge arm, the emergency power supply on the high-voltage side can provide one low-power voltage for the FS control chip circuit, without the need to supply power to the entire low-voltage side control system as in the prior art.

[0035] In the above technical solution, the power module is turned on when the signal is high, and the power module is turned off when the signal is low. In the embodiment, the pull-down resistor is used to provide a low state for the circuit when no signal is received. If the entire circuit has no power, there is definitely no signal at this time, and at this time only the main control chip 1 has no power, so a pull-down resistor needs to be added to ensure the state here and prevent false triggering.

[0036] In the above technical solution, the FS control chip 7 calculates the current motor speed by the motor current frequency obtained through three-phase current sampling, obtains the current motor back electromotive force voltage according to the motor speed and the motor back electromotive force coefficient, and when the motor back electromotive force voltage is greater than or equal to the bus voltage obtained by sampling the bus voltage, the motor power module 6 needs to work in the ASC mode and the motor outputs a slight braking torque; when the motor back electromotive force voltage is less than the bus voltage, the motor power module 6 needs to work in the shutdown mode, and all the switch tubes of the three-phase inverter bridge in the motor power module 6 are in the off state, and the motor is in free shutdown. In this way, the severe braking caused by the direct shutdown of the motor power module 6 at the high-speed stage and the severe braking caused by the ASC mode at the low-speed stage can be avoided; the current motor speed can be calculated by the sampled current frequency, the current motor back electromotive force voltage can be calculated by the speed and the back electromotive force coefficient, and whether the controller enters the ASC mode is determined by comparing the back electromotive force and the bus voltage, and then the FS control chip generates the corresponding primary side ASC signal according to the requirement.

[0037] In the technical solution, the FS control chip 7 outputs the upper bridge arm or lower bridge arm drive signal of the three-phase inverter bridge (the lower bridge arm drive signal in this embodiment) to control the motor power module 6 to work in the ASC mode when the motor power module 6 needs to work in the ASC mode, and the FS control chip 7 outputs the shutdown control signal to control the motor power module 6 to work in the shutdown mode when the motor power module 6 needs to work in the shutdown mode.

[0038] In the technical solution, it further comprises an electrical isolation device 9 and a buffer 10. The electrical isolation device 9 (optical device or magnetic device is selected for isolation, such as an optical coupler) is used to transmit the upper bridge arm or lower bridge arm drive signal of the three-phase inverter bridge output by the FS control chip 7 after electrical isolation to the buffer 10. The buffer 10 is used to enhance the driving capability of the upper bridge arm or lower bridge arm drive signal after electrical isolation through the internal totem pole push-pull circuit. The upper bridge arm or lower bridge arm drive signal with enhanced driving capability is transmitted to the driving module 5 to control the upper bridge arm or lower bridge arm switch tube of the three-phase inverter bridge in the motor power module 6 to be turned on (the lower bridge arm is turned on and the upper bridge arm is turned off in this embodiment), and the motor controller enters the ASC mode. The secondary ASC signal obtained after the primary ASC signal (lower bridge arm drive signal) is transmitted through the electrical isolation device is not transmitted to the driving chip 4, but is transmitted to the driving module 5 after the driving capability is enhanced through the buffer 10, so as to control the opening / closing of the upper bridge arm or lower bridge arm of the three-phase inverter bridge in the motor power module 6. Therefore, the driving chip 4 does not need to select a product with an ASC function pin. The logic levels of the primary ASC signal and the secondary ASC signal are the same. When the primary ASC signal is high, the secondary ASC signal is also high, and the three-channel lower bridge arm drive signal after the driving capability is enhanced is also high.

[0039] In the technical solution, it further comprises a second control power module 8 and a backup power module 11. The second control power module 8 is used to supply power to the FS control chip 7, and the backup power module 11 is used to supply power to the lower bridge arm of the driving module 5 and the second control power module 8. The backup power module 11 no longer supplies power to the entire control system.

[0040] In the technical solution, when the motor power module 6 fails, the motor controller loses power, the vehicle is parked in free sliding, and ASC control is not needed at this time.

[0041] In the above technical solution, when the motor controller is externally faulty in the motor, the battery and / or the electric control (faulty devices include: motor, battery pack, BMS, structural parts, etc., and faults include: vehicle out of control, power battery failure, motor speed too high or abnormal), and the main control chip 1 is working normally, the main control chip 1 sets the 3-way PWM signal of the upper bridge arm in the 6-way PWM signal output to the primary side of the drive chip 3 to low level, and sets the 3-way PWM signal of the lower bridge arm to high level. The drive chip 3 transmits the PWM signal with the upper bridge arm at low level and the lower bridge arm at high level to the secondary side to obtain the 6-way drive signal of the inverter bridge. The 6-way drive signal of the inverter bridge is amplified by the push-pull power amplifier of the drive module 5 to obtain the 6-way drive signal of the inverter bridge after power amplification to drive the corresponding 6-way switch tube of the motor power module 6, so as to realize the simultaneous conduction of the lower bridge arm three switch tubes (U phase upper bridge arm, V phase upper bridge arm and W phase upper bridge arm) of the inverter bridge in the motor power module 6, and the closing of the upper bridge arm three switch tubes (such as Figure 2 S1, S2 and S3 in the U phase lower bridge arm, V phase lower bridge arm and W phase lower bridge arm) of the inverter bridge in the motor power module 6. The motor controller enters the ASC mode.

[0042] In the case that there is no fault in the motor controller, the U phase upper bridge, the V phase lower bridge and the W phase lower bridge are turned on, and the other bridge arms are turned off; the V phase upper bridge, the U phase lower bridge and the W phase lower bridge are turned on, and the other bridge arms are turned off; the W phase upper bridge, the U phase lower bridge and the V phase lower bridge are turned on, and the other bridge arms are turned off. The three modes are sequentially circulated.

[0043] The motor controller includes a control board, a drive board, a power module IGBT, a bus capacitor and a structural part, Figure 1 The first control power module 2 is used for supplying power to the main control chip 1 and the drive chip 4.

[0044] In the above technical solution, when the motor controller is externally faulty in the motor, the battery and / or the electric control, and the main control chip 1 is working normally, the first control power module 2 is used for supplying power to the main control chip 1 and the drive chip 4, and the drive power module 3 is used for supplying power to the upper bridge arm drive signal generation module and the lower bridge arm drive signal generation module of the secondary side of the drive chip 4.

[0045] The application no longer needs the ASC function pin of the driving chip 4, and the number of electrical isolation devices 9 is reduced from 4-6 to only 1, because the ASC function pin of the driving chip is generally used for the ASC pin function of the high-voltage side, so that the main control chip or the FS control chip cannot directly drive the driving chip, and 6 isolators are needed. The new circuit no longer needs the driving chip with the ASC function, and does not need 6 isolators, and directly uses one buffer to drive three lower bridge arms. The backup power supply module 11 is used for supplying power to the driving module 5 and the second control power supply module 8, and can also enter the ASC mode (because the original circuit main control chip is broken, it cannot enter the ASC mode. The backup power supply of the application only supplies power to the driving module secondary side and the second control power supply module 8, and can also enter the ASC mode), so that the size and cost of the backup power supply circuit 11 are reduced. More importantly, even if the driving chip 4 fails, the FS control chip 7 can realize the ASC mode through the ASC signal.

[0046] In the technical scheme, the main control chip 1 and the FS control chip 7 can monitor the working state of each other in real time through the safety monitoring communication.

[0047] A three-phase active short-circuit protection method of an electric vehicle motor controller based on the above system, which comprises the following steps:

[0048] Step 1: The main control chip 1 and the FS control chip 7 monitor the working state of each other in real time through the safety monitoring communication.

[0049] Step 2: When the main control chip 1 fails, the FS control chip 7 samples the bus voltage and the three-phase current of the motor, judges the working mode required by the motor power module 6 according to the sampling results of the bus voltage and the three-phase current, and when the judgment result is that the motor power module 6 needs to enter the ASC mode, the FS control chip 7 outputs an enable signal to stop the working of the first control power supply module 2 and the driving power supply module 3, the main control chip 1 is powered off due to the stop of the working of the first control power supply module 2, the primary side of the driving chip 4 is powered off due to the stop of the working of the first control power supply module 2, the secondary side upper bridge arm drive signal generation module and the secondary side lower bridge arm drive signal generation module of the driving chip 4 are powered off due to the stop of the working of the driving power supply module 3, and the FS control chip 7 outputs the lower bridge arm drive signal of the three-phase inverter bridge. The lower bridge arm drive signal controls the opening of the three switching tubes of the lower bridge arm of the three-phase inverter bridge in the motor power module 6 through the driving module 5, so that the motor controller enters the ASC mode. The upper bridge arm is S1, S2 and S3 in Figure 3 , and the lower bridge arm is S4, S5 and S6 in Figure 3 . That is, the six switching tubes inside the IGBT module are used to realize the driving of the motor.

[0050] When the motor controller is externally faulty in motor, battery and / or electric control, and the main control chip 1 works normally, the main control chip 1 sets the 3-path PWM signal of the upper bridge arm in the 6-path PWM signal output to the primary side of the drive chip 3 to low level, and sets the 3-path PWM signal of the lower bridge arm to high level, the drive chip 3 transmits the PWM signal with the upper bridge arm at low level and the lower bridge arm at high level to the secondary side, obtains the 6-path drive signal of the inverter bridge, and the 6-path drive signal of the inverter bridge after push-pull power amplification by the drive module 5 obtains the power-amplified 6-path drive signal of the inverter bridge to drive the corresponding 6 switching tubes of the motor power module 6, so as to realize the simultaneous conduction of the three switching tubes of the lower bridge arm of the inverter bridge in the motor power module 6, the closing of the three switching tubes of the upper bridge arm of the inverter bridge in the motor power module 6, and the entering of the motor controller into the ASC mode.

[0051] When the motor power module 6, the motor controller loses power, the vehicle is free to slide and stop, at this time, ASC control is also not needed.

[0052] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. A three-phase active short-circuit protection system for an electric vehicle motor controller, characterized in that, It includes a main control chip (1), a first control power module (2), a drive power module (3), a drive chip (4), a drive module (5), a motor power module (6), and an FS control chip (7). When the main control chip (1) malfunctions, the FS control chip (7) samples the bus voltage and three-phase current of the motor, and determines the required operating mode of the motor power module (6) based on the results of the bus voltage and three-phase current sampling. When the determination result is that the motor power module (6) needs to enter the ASC mode, the FS control chip (7) outputs an enable signal to enable the first control power module (2) and the drive module (5). When the power supply module (3) stops working, the main control chip (1) loses power due to the first control power supply module (2) stopping working. The primary side of the drive chip (4) loses power due to the first control power supply module (2) stopping working. The secondary side upper bridge arm drive signal generation module and the secondary side lower bridge arm drive signal generation module of the drive chip (4) lose power due to the drive power supply module (3) stopping working. The upper or lower bridge arm drive signal of the three-phase inverter bridge output by the FS control chip (7) is turned on by the drive module (5) controlling the upper or lower bridge arm switch tube of the three-phase inverter bridge in the motor power module (6). It also includes an electrical isolation device (9) and a buffer (10). The electrical isolation device (9) is used to electrically isolate the drive signal of the upper or lower arm of the three-phase inverter bridge output by the FS control chip (7) and then send it to the buffer (10). The buffer (10) is used to enhance the driving capability of the drive signal of the upper or lower arm after electrical isolation. The drive signal of the upper or lower arm with enhanced driving capability is controlled by the drive module (5) to turn on the upper or lower arm switch tube of the three-phase inverter bridge in the motor power module (6), and the motor controller enters the ASC mode.

2. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 1, characterized in that: The FS control chip (7) calculates the motor speed by the current frequency obtained by the three-phase current sampling, and obtains the motor back EMF voltage based on the motor speed and the motor back EMF coefficient. When the motor back EMF voltage is greater than or equal to the bus voltage obtained by the bus voltage sampling, the motor power module (6) needs to work in ASC mode; when the motor back EMF voltage is less than the bus voltage, the motor power module (6) needs to work in shutdown mode, and all the switching transistors of the three-phase inverter bridge in the motor power module (6) are in the off state.

3. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 2, characterized in that: When the motor power module (6) needs to work in ASC mode, the FS control chip (7) outputs the upper or lower arm drive signal of the three-phase inverter bridge to control the motor power module (6) to work in ASC mode. When the motor power module (6) needs to work in stop mode, the FS control chip (7) outputs the stop control signal to control the motor power module (6) to work in stop mode.

4. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 1, characterized in that: It also includes a second control power module (8) and a backup power module (11), the second control power module (8) being used to supply power to the FS control chip (7), and the backup power module (11) being used to supply power to the drive module (5) and the second control power module (8).

5. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 1, characterized in that: When the motor power module (6) fails, the motor controller loses power and the vehicle coasts to a stop. At this time, there is no need to perform ASC control.

6. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 1, characterized in that: When the motor, battery and / or electronic control of the motor controller fails, but the main control chip (1) is working normally, the main control chip (1) sets the PWM signal of the upper bridge arm of the PWM signal output to the primary side of the drive chip (4) to a low level and the PWM signal of the lower bridge arm to a high level. The drive chip (4) transmits the PWM signal with the upper bridge arm at a low level and the lower bridge arm at a high level to the secondary side to obtain the inverter bridge drive signal. After the inverter bridge drive signal is amplified by the drive module (5) through push-pull power amplification, the amplified inverter bridge drive signal is used to drive the corresponding switch of the motor power module (6) to operate, thereby realizing the simultaneous conduction of the lower bridge arm switch of the inverter bridge in the motor power module (6) and the shutdown of the upper bridge arm switch of the inverter bridge in the motor power module (6). The motor controller enters ASC mode.

7. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 6, characterized in that: When the motor, battery and / or electronic control of the motor controller fails, but the main control chip (1) is working normally, the first control power module (2) is used to supply power to the primary side of the main control chip (1) and the drive chip (4), and the drive power module (3) is used to supply power to the secondary side upper bridge arm drive signal generation module and the secondary side lower bridge arm drive signal generation module of the drive chip (4).

8. The three-phase active short-circuit protection system for electric vehicle motor controllers according to claim 1, characterized in that: The main control chip (1) and the FS control chip (7) can monitor each other's working status in real time through security monitoring communication.

9. A method for three-phase active short-circuit protection of an electric vehicle motor controller based on the system described in claim 1, characterized in that, It includes the following steps: Step 1: The main control chip (1) and the FS control chip (7) monitor each other's working status in real time through secure monitoring communication; Step 2: When the main control chip (1) malfunctions, the FS control chip (7) samples the bus voltage and three-phase current of the motor, and determines the required operating mode of the motor power module (6) based on the results of the bus voltage and three-phase current sampling. When the determination result is that the motor power module (6) needs to enter ASC mode, the FS control chip (7) outputs an enable signal to stop the first control power module (2) and the drive power module (3) from working. The main control chip (1) drops due to the first control power module (2) stopping working. The primary side of the drive chip (4) is powered off due to the first control power module (2) stopping work. The secondary side upper bridge arm drive signal generation module and the secondary side lower bridge arm drive signal generation module of the drive chip (4) are powered off due to the drive power module (3) stopping work. The upper or lower bridge arm drive signal of the three-phase inverter bridge output by the FS control chip (7) is turned on by the drive module (5) controlling the upper or lower bridge arm switch tube of the three-phase inverter bridge in the motor power module (6), and the motor controller enters ASC mode. When the motor, battery and / or electronic control of the motor controller fails, but the main control chip (1) is working normally, the main control chip (1) sets the PWM signal of the upper bridge arm of the PWM signal output to the primary side of the drive chip (4) to a low level and the PWM signal of the lower bridge arm to a high level. The drive chip (4) transmits the PWM signal with the upper bridge arm at a low level and the lower bridge arm at a high level to the secondary side to obtain the inverter bridge drive signal. After the inverter bridge drive signal is amplified by the drive module (5) through push-pull power amplification, the amplified inverter bridge drive signal is used to drive the corresponding switch of the motor power module (6) to act, thereby realizing the simultaneous conduction of the lower bridge arm switch of the inverter bridge in the motor power module (6) and the shutdown of the upper bridge arm switch of the inverter bridge in the motor power module (6). The motor controller enters ASC mode. When the motor power module (6) is activated, the motor controller loses power and the vehicle coasts to a stop. At this time, there is no need for ASC control.

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