Control circuit and method of motor controller

Abstract

The invention discloses a control circuit and method of a motor controller, and relates to the technical field of vehicle protection. The control circuit comprises an emergency power supply circuit, the two input ends of the emergency power supply circuit are connected with a direct current bus and a reference voltage end respectively, and the emergency power supply circuit is used for providing a power supply signal under the condition that the direct current bus voltage generated based on the counter electromotive force of the motor is larger than or equal to the reference voltage; the power supply end of the bridge driving chip is connected with the emergency power supply circuit, and the bridge driving chip is used for driving each bridge arm of the motor controller; the power supply end of the auxiliary control chip is connected with the emergency power supply circuit, and the control signal end of the auxiliary control chip is connected with the bridge driving chip; and under the condition that the auxiliary control chip receives the power supply signal, the auxiliary control chip is used for sending a first conduction instruction to the bridge driving chip, and the bridge driving chip responds to the first conduction instruction and drives at least one lower bridge arm to be conducted so as to enable the motor to discharge.

Description

Technical Field

[0001] The present application belongs to the field of vehicle protection technology, and in particular, relates to a control circuit and method of a motor controller. Background Art

[0002] At present, electric vehicles are widely used. When an electric vehicle is driving, the vehicle controller converts the driver's driving intention into a torque request and sends it to the motor controller, which controls the motor to output torque and drive the vehicle.

[0003] In actual applications, when the battery of an electric vehicle is running low on power or losing power, the electric vehicle needs to be towed to a charging station or maintenance station for rescue.

[0004] However, when the battery is powered on or off, all bridge arms in the motor controller are in the off state. Driving an electric vehicle will generate a certain amount of back electromotive force, which is prone to current backflow, thus damaging the motor. Summary of the invention

[0005] The embodiments of the present application provide a control circuit and method for a motor controller, which can improve the safety of the motor.

[0006] According to a first aspect of an embodiment of the present application, a control circuit of a motor controller is provided, comprising:

[0007] An emergency power supply circuit, wherein two input terminals of the emergency power supply circuit are respectively connected to a DC bus and a reference voltage terminal, and the emergency power supply circuit is used to provide a power supply signal when a DC bus voltage generated based on a back electromotive force of the motor is greater than or equal to a reference voltage;

[0008] A bridge driver chip, a power supply end of the bridge driver chip is connected to the emergency power supply circuit, and the bridge driver chip is used to drive each bridge arm of the motor controller;

[0009] An auxiliary control chip, wherein a power supply terminal of the auxiliary control chip is connected to an emergency power supply circuit, and a control signal terminal of the auxiliary control chip is connected to a bridge driver chip;

[0010] When the auxiliary control chip receives the power supply signal, the auxiliary control chip is used to send a first conduction instruction to the bridge driver chip. In response to the first conduction instruction, the bridge driver chip drives at least one lower bridge arm to conduct so that the motor discharges.

[0011] A second aspect of an embodiment of the present application provides a control method of a motor controller, which is applied to an auxiliary control chip in a control circuit of the motor controller provided in the embodiment of the present application, comprising:

[0012] When the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, receiving a power supply signal provided by the emergency power supply circuit;

[0013] When the power supply signal is received, a first conduction instruction is sent to the bridge driver chip, so that the bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct.

[0014] In the control circuit and method of the motor controller provided in the embodiment of the present application, when the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, it is explained that the phenomenon of current backflow is prone to occur at this time. At this time, the emergency power supply circuit will provide a power supply signal. Then, when the auxiliary control chip receives the power supply signal, it will send a first conduction instruction to the bridge driver chip. The bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct so that the motor can discharge. In this way, the embodiment of the present application can avoid current backflow caused by excessive back electromotive force by actively discharging the motor, thereby improving the safety of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 is a structural schematic diagram of a control circuit of a motor controller provided by an embodiment of the present application;

[0017] Figure 2 is a flow chart of a control method of a motor controller provided by an embodiment of the present application;

[0018] Figure 3 This is a schematic diagram of the relationship between the speed and torque of a motor in an active short-circuit mode provided by an embodiment of the present application. DETAILED DESCRIPTION

[0019] The features and exemplary embodiments of each aspect of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0020] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The embodiments will be described in detail below in conjunction with the accompanying drawings.

[0022] At present, electric vehicles are widely used. When an electric vehicle is driving, the vehicle controller converts the driver's driving intention into a torque request and sends it to the motor controller, which controls the motor to output torque to drive the vehicle. In actual applications, when the battery of an electric vehicle is powered on or off, the electric vehicle needs to be towed to a charging station or maintenance station for rescue.

[0023] However, when the battery is powered on or off, all bridge arms in the motor controller are in the off state. Driving an electric vehicle will generate a certain amount of back electromotive force, which is prone to current backflow, thus damaging the motor.

[0024] In order to solve the above technical problems, the embodiments of the present application provide a control circuit and method for a motor controller. In the control circuit and method of the motor controller provided in the embodiments of the present application, when the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, it is explained that the phenomenon of current backflow is prone to occur at this time. At this time, the emergency power supply circuit will provide a power supply signal. Then, when the auxiliary control chip receives the power supply signal, it will send a first conduction instruction to the bridge driver chip. In response to the first conduction instruction, the bridge driver chip drives at least one lower bridge arm to conduct so that the motor is discharged. In this way, the embodiments of the present application can avoid current backflow caused by excessive back electromotive force by actively discharging the motor, thereby improving the safety of the motor.

[0025] The following describes a specific embodiment of the control circuit and method of the motor controller provided by the embodiment of the present application. First, the control circuit of the motor controller is introduced.

[0026] Figure 1 The schematic diagram of the structure of the control circuit of the motor controller provided by one embodiment of the present application is shown. The control circuit of the motor controller may include an emergency power supply circuit 130 , a bridge driver chip 160 and an auxiliary control chip 150 .

[0027] The two input terminals of the emergency power supply circuit 130 are respectively connected to the DC bus 110 and the reference voltage terminal 120. The emergency power supply circuit 130 is used to provide a power supply signal when the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage.

[0028] The power supply end of the bridge driver chip 160 is connected to the emergency power supply circuit 130 , and the bridge driver chip 160 is used to drive each bridge arm of the motor controller 170 ;

[0029] The power supply end of the auxiliary control chip 150 is connected to the emergency power supply circuit 130 , and the control signal end of the auxiliary control chip 150 is connected to the bridge driver chip 160 ;

[0030] When the auxiliary control chip 150 receives the power supply signal, the auxiliary control chip 150 is used to send a first conduction instruction to the bridge driver chip 160. In response to the first conduction instruction, the bridge driver chip 160 drives at least one lower bridge arm 171 to conduct so that the motor discharges.

[0031] In this embodiment, the emergency power supply circuit 130 may include a comparator and a voltage regulation module, which is used to compare the magnitude relationship between the voltage signals received at the two input terminals, that is, the relationship between the DC bus voltage output by the DC bus 110 and the reference voltage output by the reference voltage terminal 120.

[0032] Among them, when the DC bus voltage is greater than or equal to the reference voltage, it means that the motor generates too high back electromotive force. At this time, the emergency power supply circuit 130 will be activated, and the output end of the emergency power supply circuit 130 will output a power supply signal to the bridge driver chip 160 and the auxiliary control chip 150.

[0033] It should be noted that current electric vehicles generally use permanent magnet synchronous motors, and when towing or manpower-pushing rescue is carried out on electric vehicles, the permanent magnet synchronous motor will generate back electromotive force. At the same time, the back electromotive force generated by the permanent magnet synchronous motor will charge the capacitor in the DC bus 110, so that the DC bus voltage output by the DC bus 110 will continue to increase, that is, the DC bus voltage output by the DC bus 110 will change with the change of the towing rescue speed; the reference voltage output by the reference voltage terminal 120 is used to determine whether the motor is in danger of current backflow, that is, the reference voltage output by the reference voltage terminal 120 is a pre-set safety voltage threshold.

[0034] When the auxiliary control chip 150 receives the power supply signal output by the emergency power supply circuit 130, it indicates that the DC bus voltage output by the DC bus 110 is greater than or equal to the reference voltage output by the reference voltage terminal 120, that is, the motor is in danger of current backflow. Therefore, the auxiliary control chip 150 sends a first conduction instruction to the bridge driver chip 160, so that the bridge driver chip 160 drives at least one lower bridge arm 171 to conduct, thereby discharging the motor.

[0035] The bridge driver chip 160 will be activated when it receives the power supply signal provided by the emergency power supply circuit 130 and the first conduction instruction sent by the auxiliary control chip 150. At this time, the output end of the bridge driver chip 160 will output a conduction signal to the bridge arm in the motor controller 170 to drive at least one lower bridge arm 171 in the motor controller 170 to conduct, so as to discharge the motor.

[0036] It should be noted that the motor controller 170 may include a three-phase inverter bridge composed of six power switch tubes, and the three-phase inverter bridge includes three lower bridge arms 171 of U-phase lower bridge arm, V-phase lower bridge arm, and W-phase lower bridge arm, and three upper bridge arms 172 of U-phase upper bridge arm, V-phase upper bridge arm, and W-phase upper bridge arm. Therefore, the bridge driver chip 160 can choose to drive any one of the lower bridge arms 171 of U-phase lower bridge arm, V-phase lower bridge arm, and W-phase lower bridge arm to conduct, or can choose to drive any two of the lower bridge arms 171 of U-phase lower bridge arm, V-phase lower bridge arm, and W-phase lower bridge arm to conduct, and can also choose to drive all three lower bridge arms 171 of U-phase lower bridge arm, V-phase lower bridge arm, and W-phase lower bridge arm to conduct.

[0037] It should be noted that the power switch tube in the three-phase inverter bridge can be an insulated gate bipolar transistor (IGBT), and each IGBT power tube is connected between the positive or negative pole of the DC bus 110 and the three-phase AC output terminal. These IGBT power tubes are arranged in a specific manner to form three bridge arms, each bridge arm includes two IGBT power tubes, which are respectively called the upper bridge arm 172 and the lower bridge arm 171.

[0038] Furthermore, when at least one lower bridge arm 171 in the motor controller 170 is turned on, the motor is in a discharge state, and the DC bus voltage output by the DC bus 110 will slowly decrease. When the DC bus voltage output by the DC bus 110 drops to a value lower than the reference voltage output by the reference voltage terminal 120, the emergency power supply circuit 130 no longer meets the activation condition, that is, the output terminal of the emergency power supply circuit 130 will no longer output a power supply signal to the bridge driver chip 160 and the auxiliary control chip 150. At this time, the bridge driver chip 160 and the auxiliary control chip 150 will be reset to a non-operating state due to lack of power supply, so that each bridge arm in the motor controller 170 is disconnected until the next time the emergency power supply circuit 130 outputs a power supply signal.

[0039] It should be noted that when all bridge arms in the motor controller 170 are disconnected, the motor will enter a free wheeling (FW) mode, and the capacitor of the DC bus 110 will be briefly charged by the energy at the motor end.

[0040] In the control circuit of the motor controller provided in this embodiment, when the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, it is explained that the phenomenon of current backflow is prone to occur at this time. At this time, the emergency power supply circuit 130 will provide a power supply signal. Then, when the auxiliary control chip 150 receives the power supply signal, it will send a first conduction instruction to the bridge driver chip 160. In response to the first conduction instruction, the bridge driver chip 160 drives at least one lower bridge arm 171 to conduct so that the motor can discharge. In this way, the embodiment of the present application can avoid current backflow caused by excessive back electromotive force by actively discharging the motor, thereby improving the safety of the motor.

[0041] In one embodiment, the above-mentioned bridge driver chip 160 may include a lower bridge driver chip 161, the output end of the lower bridge driver chip 161 is connected to the control end of at least one lower bridge arm 171 of the motor controller 170, and the lower bridge driver chip 161 is used to respond to the first conduction instruction and send a conduction signal to the corresponding lower bridge arm 171.

[0042] In this embodiment, the lower bridge driver chip 161 is a sub-chip in the bridge driver chip 160, and is used to specifically control the conduction and disconnection of the lower bridge arm 171. The input end of the lower bridge driver chip 161 is connected to the control signal end of the auxiliary control chip 150. When receiving the first conduction instruction sent by the auxiliary control chip 150, the output end of the lower bridge driver chip 161 will send a conduction signal to at least one lower bridge arm 171 connected thereto.

[0043] The output end of the lower bridge driver chip 161 can be connected to the control end of at least one lower bridge arm 171 of the U-phase lower bridge arm, the V-phase lower bridge arm, and the W-phase lower bridge arm. For example, when the output end of the lower bridge driver chip 161 is only connected to the control end of the U-phase lower bridge arm, the lower bridge driver chip 161 responds to the first conduction instruction and sends a conduction signal to the control end of the U-phase lower bridge arm; when the output end of the lower bridge driver chip 161 is simultaneously connected to the control ends of the U-phase lower bridge arm and the V-phase lower bridge arm, the lower bridge driver chip 161 responds to the first conduction instruction and sends a conduction signal to the control ends of the U-phase lower bridge arm and the V-phase lower bridge arm at the same time.

[0044] In one embodiment, the output end of the lower bridge driving chip 161 is connected to the control ends of the three lower bridge arms 171 of the motor controller 170 .

[0045] In this embodiment, the output end of the lower bridge driving chip 161 is simultaneously connected to the control ends of the U-phase lower bridge arm, the V-phase lower bridge arm, and the W-phase lower bridge arm. When the lower bridge driving chip 161 receives the first conduction instruction, it will simultaneously send a conduction signal to the control ends of the U-phase lower bridge arm, the V-phase lower bridge arm, and the W-phase lower bridge arm, so that the U-phase lower bridge arm, the V-phase lower bridge arm, and the W-phase lower bridge arm are simultaneously turned on.

[0046] It should be noted that when the U-phase lower bridge arm, the V-phase lower bridge arm and the W-phase lower bridge arm are turned on at the same time, the motor enters the active short circuit (ASC) mode. At this time, the motor stator winding will be driven to form a closed loop, generating reverse torque, so that the vehicle brakes slowly and avoids the current backflow caused by excessive back electromotive force.

[0047] In one embodiment, the bridge driver chip 160 may further include an upper bridge driver chip 162 , the output end of the upper bridge driver chip 162 being connected to the control end of at least one upper bridge arm 172 of the motor controller 170 ;

[0048] The auxiliary control chip 150 is connected to the vehicle controller 140. When the auxiliary control chip 150 receives a power supply signal and an active discharge instruction sent by the vehicle controller 140, the auxiliary control chip 150 is used to send a second conduction instruction to the bridge driver chip 160. The bridge driver chip 160 responds to the second conduction instruction to drive all lower bridge arms 171 and at least one upper bridge arm 172 to be turned on.

[0049] In this embodiment, the upper bridge driver chip 162 is a sub-chip in the bridge driver chip 160, and is used to specifically control the on and off of the upper bridge arm 172. The input end of the upper bridge driver chip 162 is connected to the control signal end of the auxiliary control chip 150. When receiving the second on instruction sent by the auxiliary control chip 150, the output end of the upper bridge driver chip 162 sends an on signal to at least one upper bridge arm 172 connected thereto.

[0050] The output end of the upper bridge driver chip 162 can be connected to the control end of at least one upper bridge arm 172 of the U-phase upper bridge arm, the V-phase upper bridge arm, and the W-phase upper bridge arm. For example, when the output end of the upper bridge driver chip 162 is only connected to the control end of the U-phase upper bridge arm, the upper bridge driver chip 162 responds to the second conduction instruction and sends a conduction signal to the control end of the U-phase upper bridge arm.

[0051] It should be noted that the auxiliary control chip 150 is also connected to the vehicle controller 140. In the case of a sudden power failure of a normally running vehicle, the back electromotive force suddenly generated at this time is too high, and the motor needs to be actively discharged. Therefore, the vehicle controller 140 will send an active discharge instruction to the auxiliary control chip 150 at this time.

[0052] When the auxiliary control chip 150 receives the power supply signal sent by the emergency power supply circuit 130 and the active discharge instruction sent by the vehicle controller 140, it will send a second conduction instruction to the lower bridge driver chip 161 and the upper bridge driver chip 162. In response to the second conduction instruction, the lower bridge driver chip 161 will drive the U-phase lower bridge arm, the V-phase lower bridge arm and the W-phase lower bridge arm to be turned on at the same time, so that the motor enters the ASC mode; at the same time, the upper bridge driver chip 162 will drive the U-phase upper bridge arm to be turned on in response to the second conduction instruction to further increase the discharge efficiency.

[0053] It should be noted that the auxiliary control chip 150 can simultaneously receive the power supply signal sent by the emergency power supply circuit 130 and the active discharge instruction sent by the vehicle controller 140, or it may not simultaneously receive the power supply signal sent by the emergency power supply circuit 130 and the active discharge instruction sent by the vehicle controller 140.

[0054] Specifically, when the auxiliary control chip 150 simultaneously receives the power supply signal sent by the emergency power supply circuit 130 and the active discharge instruction sent by the vehicle controller 140, the auxiliary control chip 150 will directly send a second turn-on instruction to the lower bridge driver chip 161 and the upper bridge driver chip 162; when the auxiliary control chip 150 first receives the power supply signal sent by the emergency power supply circuit 130, the auxiliary control chip 150 will first send a first turn-on instruction to the lower bridge driver chip 161, and then when it receives the active discharge instruction sent by the vehicle controller 140, it will send a second turn-on instruction to the upper bridge driver chip 162 to drive at least one upper bridge arm 172 to also be turned on.

[0055] In one embodiment, the three power supply signal terminals of the emergency power supply circuit 130 are respectively connected to the upper bridge driver chip 162, the auxiliary control chip 150 and the lower bridge driver chip 161;

[0056] When the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, the emergency power supply circuit 130 is used to convert the DC bus voltage into a first power supply voltage corresponding to the upper bridge driver chip 162, a second power supply voltage corresponding to the auxiliary control chip 150, and a third power supply voltage corresponding to the lower bridge driver chip 161.

[0057] In this embodiment, the emergency power supply circuit 130 has three power supply signal terminals, which respectively serve as power supply voltage sources corresponding to the upper bridge driving chip 162 , the auxiliary control chip 150 , and the lower bridge driving chip 161 .

[0058] It should be noted that the emergency power supply circuit 130 can be a flyback converter circuit, which is used to step down the DC bus voltage through a transformer, thereby outputting the power supply voltages required by the upper bridge driver chip 162, the auxiliary control chip 150 and the lower bridge driver chip 161 respectively.

[0059] The upper bridge arm 172 is connected to the positive pole of the DC bus, which is at a high potential. Therefore, the first power supply voltage required by the upper bridge driver chip 162 to drive the upper bridge arm 172 to conduct is relatively high. For example, the first power supply voltage corresponding to the upper bridge driver chip 162 may be 15V.

[0060] The auxiliary control chip 150 is a microcontroller, so the second power supply voltage corresponding to the auxiliary control chip 150 is the power supply voltage required by the microcontroller. For example, the second power supply voltage corresponding to the auxiliary control chip 150 may be 5V.

[0061] The lower bridge arm 171 is connected to the negative pole of the DC bus, which is at a negative potential. Therefore, the third power supply voltage required for the lower bridge driver chip 161 to drive the lower bridge arm 171 to conduct is relatively low. For example, the third power supply voltage corresponding to the lower bridge driver chip 161 may be -15V.

[0062] A control circuit based on a motor controller. Accordingly, the present application also provides a specific embodiment of a control method of a motor controller.

[0063] Figure 2 A flow chart of a control method of a motor controller provided by an embodiment of the present application is shown. The control method of the motor controller is applied to an auxiliary control chip in a control circuit of the motor controller, and the control method of the motor controller may include the following S201 to S202.

[0064] S201, receiving a power supply signal provided by an emergency power supply circuit when a DC bus voltage generated based on a back electromotive force of the motor is greater than or equal to a reference voltage;

[0065] S202 , when receiving a power supply signal, sending a first conduction instruction to the bridge driver chip, so that the bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct.

[0066] In this embodiment, the back electromotive force is used to indicate that when the motor rotates, due to electromagnetic induction, an electromotive force opposite to the direction of the external voltage is generated, namely, the back electromotive force.

[0067] The DC bus voltage is used to represent the voltage obtained after the back electromotive force generated by the motor charges the capacitor in the DC bus.

[0068] The reference voltage is a preset safety voltage threshold value, which is used to determine whether the motor is in danger of current backflow.

[0069] As an example, the emergency power supply circuit compares the magnitude relationship between the DC bus voltage and the reference voltage in real time. When the DC bus voltage is greater than or equal to the reference voltage, the emergency power supply circuit is activated and outputs a power supply signal to the auxiliary control chip and the bridge driver chip.

[0070] When the auxiliary control chip receives the power supply signal, it indicates that the DC bus voltage output by the DC bus is greater than or equal to the reference voltage output by the reference voltage terminal, that is, the motor is in danger of current backflow. Therefore, the auxiliary control chip generates a first conduction instruction according to a preset logic or algorithm. The first conduction instruction can be an analog level (such as a high level) or a digital signal (such as a specific PWM waveform).

[0071] Then, the auxiliary control chip sends the first conduction instruction to the bridge driver chip through the control signal terminal. After receiving the first conduction instruction, the bridge driver chip generates a corresponding drive signal to conduct the three lower bridge arms in the three-phase bridge according to the internal logic or preset configuration, so that the motor enters the ASC mode.

[0072] In the control method of the motor controller provided in the present embodiment, when the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, it is explained that the phenomenon of current backflow is prone to occur at this time. At this time, the emergency power supply circuit will provide a power supply signal. Then, when the auxiliary control chip receives the power supply signal, it will send a first conduction instruction to the bridge driver chip. The bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct so that the motor can discharge. In this way, the embodiment of the present application can avoid current backflow caused by excessive back electromotive force by actively discharging the motor, thereby improving the safety of the motor.

[0073] In one embodiment, after S202, the control method of the motor controller may further include:

[0074] When the DC bus voltage generated based on the back electromotive force of the motor is less than the reference voltage, in response to the emergency power supply circuit stopping providing the power supply signal, the first conduction instruction is stopped from being sent to the bridge driver chip.

[0075] In this embodiment, as an example, after the auxiliary control chip sends a first conduction instruction to the bridge driver chip, so that the bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct, the motor will be in a discharge state, and the DC bus voltage output by the DC bus will slowly decrease.

[0076] At the same time, the emergency power supply circuit will continue to monitor the DC bus voltage and compare the DC bus voltage with the reference voltage in real time. When the DC bus voltage is less than the reference voltage, the emergency power supply circuit no longer meets the activation condition, that is, the emergency power supply circuit no longer outputs a power supply signal to the auxiliary control chip and the bridge driver chip.

[0077] When the emergency power supply circuit stops providing the power supply signal, the auxiliary control chip will reset to a non-operating state due to lack of power supply, that is, the auxiliary control chip will stop sending the first conduction instruction to the bridge driver chip. At this time, the three lower bridge arms will be disconnected, and the motor will re-enter the FW mode, and the capacitor of the DC bus will be briefly charged by the energy at the motor end. Until the next time when the DC bus voltage is greater than or equal to the reference voltage, the control method of the motor controller provided in the above embodiment is circulated.

[0078] Through this embodiment, when the DC bus voltage is less than the reference voltage, the motor re-enters the free-wheeling mode, so that the electric vehicle can be towed when the battery is powered on or off. In this way, by alternately switching between the free-wheeling mode and the active short-circuit mode, the electric vehicle can be safely rescued when the battery is powered on or off.

[0079] In one embodiment, after S201, the control method of the motor controller may further include:

[0080] In response to the active discharge instruction sent by the vehicle controller, a second conduction instruction is sent to the bridge driver chip, so that the bridge driver chip responds to the second conduction instruction and drives all lower bridge arms and at least one upper bridge arm to conduct.

[0081] In this embodiment, as an example, the auxiliary control chip not only receives the power supply signal sent by the emergency power supply circuit, but also receives the active discharge instruction sent by the vehicle controller. This indicates that the suddenly generated back electromotive force is too high and the motor needs to be actively discharged.

[0082] At this time, the auxiliary control chip will generate a second conduction instruction according to the preset logic or algorithm. The second conduction instruction can be an analog level (such as a high level) or a digital signal (such as a specific PWM waveform). Then the auxiliary control chip sends the second conduction instruction to the bridge driver chip through the control signal terminal.

[0083] After receiving the second conduction instruction, the bridge driver chip generates a corresponding drive signal to turn on the three lower bridge arms in the three-phase bridge according to the internal logic or preset configuration, so that the motor enters the ASC mode; at the same time, it further turns on the U-phase upper bridge arm, so that the discharge efficiency can be further increased.

[0084] Through this embodiment, when the suddenly generated back electromotive force is too high and the motor needs to be actively discharged, the auxiliary control chip not only controls the three lower bridge arms to be turned on, but also further turns on the U-phase upper bridge arm, thereby further increasing the discharge efficiency and further improving the safety of the electric vehicle during rescue.

[0085] In one embodiment, the second conduction instruction includes a conduction duty cycle of the upper bridge arm, where the conduction duty cycle is used to characterize the frequency and duration of conduction;

[0086] In response to the active discharge instruction sent by the vehicle controller, a second conduction instruction is sent to the bridge driver chip, so that the bridge driver chip responds to the second conduction instruction and drives all lower bridge arms and at least one upper bridge arm to conduct, which may specifically include:

[0087] In response to the active discharge instruction sent by the vehicle controller, a second conduction instruction is sent to the bridge driver chip, so that the bridge driver chip drives all lower bridge arms to conduct in response to the second conduction instruction, and drives at least one upper bridge arm to conduct and disconnect based on the conduction duty cycle.

[0088] In this embodiment, the second conduction instruction includes the conduction duty cycle of the upper bridge arm, and the conduction duty cycle is used to characterize the conduction frequency and duration of the upper bridge arm. Among them, the conduction duty cycle can be a preset value. For example, the conduction duty cycle can be turned on once every 5 seconds, and the conduction duration each time is 1 second.

[0089] As an example, when the auxiliary control chip receives the power supply signal sent by the emergency power supply circuit and the active discharge instruction sent by the vehicle controller at the same time, the auxiliary control chip will generate a second conduction instruction according to the preset logic or algorithm. Then the auxiliary control chip sends the second conduction instruction to the bridge driver chip through the control signal terminal.

[0090] After receiving the second conduction instruction, the bridge driver chip generates a corresponding drive signal to turn on the three lower bridge arms in the three-phase bridge according to the internal logic or preset configuration, so that the motor enters the ASC mode; at the same time, the bridge driver chip will also turn on the U-phase upper bridge arm every 5 seconds according to the conduction duty cycle of the upper bridge arm in the second conduction instruction, and each conduction time is 1 second, so that the discharge efficiency can be further increased.

[0091] Through this embodiment, the discharge efficiency can be controlled according to the on-duty ratio, so that the safety of the motor can be further improved by controlling the discharge efficiency.

[0092] In one embodiment, the reference voltage is a voltage threshold corresponding to a target speed that satisfies a preset speed condition, and the preset speed condition is that the speed of the motor is greater than or equal to a preset speed threshold.

[0093] In this embodiment, if Figure 3 As shown, a schematic diagram of the relationship between the speed and torque of the motor in the active short-circuit mode is provided, wherein the horizontal axis is the speed of the motor in the active short-circuit mode, and the vertical axis is the torque of the motor in the active short-circuit mode.

[0094] according to Figure 3 It can be seen that the negative torque is too large within 1000 revolutions, and when the negative torque is too large, it will affect the trailer and cause impact. Therefore, the preset speed threshold can be set to 1000 revolutions, and the preset speed condition is that the motor speed is greater than or equal to 1000 revolutions.

[0095] The reference voltage is a voltage threshold corresponding to a target speed that satisfies a preset speed condition. For example, when the preset speed condition is that the motor speed is greater than or equal to 1000 rpm, 1500 rpm can be set as the target speed, that is, the voltage threshold corresponding to 1500 rpm is determined as the reference voltage.

[0096] Through this embodiment, the reference voltage is accurately determined according to the relationship between the speed and torque of the motor in the active short-circuit mode, so that it is possible to accurately judge whether the motor is in danger of current backflow according to the reference voltage, thereby improving the safety of the motor.

[0097] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0098] The functional blocks shown in the above-described block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present application are programs or code segments that are used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link by a data signal carried in a carrier wave. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0099] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0100] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0101] This article uses specific examples to illustrate the principles and implementation methods of this application. The above examples are only used to help understand the methods and core ideas of this application. The above are only preferred implementation methods of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concepts and technical solutions of this application to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. A control circuit of a motor controller, applied to a vehicle, characterized in that: The circuit comprises: An emergency power supply circuit, wherein two input terminals of the emergency power supply circuit are respectively connected to a DC bus and a reference voltage terminal, and the emergency power supply circuit is used to provide a power supply signal when a DC bus voltage generated based on a back electromotive force of the motor is greater than or equal to a reference voltage; A bridge driver chip, a power supply end of the bridge driver chip is connected to the emergency power supply circuit, and the bridge driver chip is used to drive each bridge arm of the motor controller; An auxiliary control chip, wherein a power supply terminal of the auxiliary control chip is connected to the emergency power supply circuit, and a control signal terminal of the auxiliary control chip is connected to the bridge driver chip; When the auxiliary control chip receives the power supply signal, the auxiliary control chip is used to send a first conduction instruction to the bridge driver chip, and the bridge driver chip responds to the first conduction instruction to drive at least one lower bridge arm to conduct so that the motor discharges.

2. The control circuit of the motor controller according to claim 1, characterized in that: The bridge driver chip comprises: A lower bridge driver chip, wherein the output end of the lower bridge driver chip is connected to the control end of at least one lower bridge arm of the motor controller, and the lower bridge driver chip is used to send a conduction signal to the corresponding lower bridge arm in response to the first conduction instruction.

3. The control circuit of the motor controller according to claim 2, characterized in that: The output end of the lower bridge driving chip is connected to the control ends of the three lower bridge arms of the motor controller.

4. The control circuit of the motor controller according to claim 3, characterized in that: The bridge driver chip also includes: An upper bridge driving chip, wherein an output end of the upper bridge driving chip is connected to a control end of at least one upper bridge arm of the motor controller; The auxiliary control chip is connected to the vehicle controller. When the auxiliary control chip receives the power supply signal and the active discharge instruction sent by the vehicle controller, the auxiliary control chip is used to send a second conduction instruction to the bridge drive chip. The bridge drive chip responds to the second conduction instruction to drive all lower bridge arms and at least one upper bridge arm to conduct.

5. The control circuit of the motor controller according to claim 4, characterized in that: The three power supply signal terminals of the emergency power supply circuit are respectively connected to the upper bridge drive chip, the auxiliary control chip and the lower bridge drive chip; When the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, the emergency power supply circuit is used to convert the DC bus voltage into a first power supply voltage corresponding to the upper bridge driver chip, a second power supply voltage corresponding to the auxiliary control chip, and a third power supply voltage corresponding to the lower bridge driver chip.

6. A control method for a motor controller, applied to an auxiliary control chip in a control circuit of a motor controller according to any one of claims 1 to 5, characterized in that: The method comprises: When the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, receiving a power supply signal provided by the emergency power supply circuit; When the power supply signal is received, a first conduction instruction is sent to the bridge driver chip, so that the bridge driver chip responds to the first conduction instruction and drives at least one lower bridge arm to conduct.

7. The method according to claim 6, characterized in that After sending a first conduction instruction to the bridge driver chip when the power supply signal is received, the method further includes: When the DC bus voltage generated based on the back electromotive force of the motor is less than the reference voltage, in response to the emergency power supply circuit stopping providing the power supply signal, the first conduction instruction is stopped from being sent to the bridge driver chip.

8. The method according to claim 6, characterized in that In the case where the DC bus voltage generated based on the back electromotive force of the motor is greater than or equal to the reference voltage, after receiving the power supply signal provided by the emergency power supply circuit, the method further includes: In response to the active discharge instruction sent by the vehicle controller, a second conduction instruction is sent to the bridge driver chip, so that the bridge driver chip responds to the second conduction instruction and drives all lower bridge arms and at least one upper bridge arm to conduct.

9. The method according to claim 8, characterized in that The second conduction instruction includes a conduction duty cycle of the upper bridge arm, and the conduction duty cycle is used to characterize the frequency and duration of conduction; The step of sending a second conduction instruction to the bridge driver chip in response to the active discharge instruction sent by the vehicle controller, so that the bridge driver chip drives all lower bridge arms and at least one upper bridge arm to conduct in response to the second conduction instruction, comprises: In response to the active discharge instruction sent by the vehicle controller, a second conduction instruction is sent to the bridge driver chip, so that the bridge driver chip drives all lower bridge arms to turn on in response to the second conduction instruction, and drives at least one upper bridge arm to turn on and off based on the conduction duty cycle.

10. The method according to any one of claims 6 to 9, characterized in that: The reference voltage is a voltage threshold corresponding to a target speed that satisfies a preset speed condition, and the preset speed condition is that the speed of the motor is greater than or equal to a preset speed threshold.

Images