Motor protection device and method

Abstract

The embodiment of the present application provides a motor protection device and method, the device includes a controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits and three first resistors; the controller is used to send a control signal to the driver to control the on-off state of each branch in the three-phase bridge rectifier circuit and / or the switching circuit; the driver is used to apply voltage to the gate of the first IGBT and / or the gate of the second IGBT through the received control signal and provide a driving current to control the on-off state of the first IGBT and / or the second IGBT; the three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor and support active short-circuit operation; the switching circuit is used to switch to a preset branch according to the control signal received from the controller to protect the motor. The motor protection device provided by this embodiment can overcome the problem that the prior art cannot reduce torque in a timely and effective manner, and thus cannot protect the vehicle power system, and affects the driving experience.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of motor protection, and in particular, to a motor protection device and method. Background Art

[0002] To ensure personal safety, vehicles need to have active discharge function. The current active discharge technology mainly discharges through motor windings. Discharging through motor windings has a fast discharge time, but it will bring unexpected torque and affect the driving experience.

[0003] Secondly, when a vehicle malfunctions and suddenly becomes unable to drive, it will seriously affect the controller and motor, causing a large torque shock, which in turn affects the driving experience and the vehicle's power system.

[0004] Therefore, under the above working conditions, the existing technology cannot effectively reduce the torque in a timely manner, thereby failing to protect the vehicle power system and affecting the driving experience. Summary of the invention

[0005] The embodiments of the present application provide a motor protection device and method to overcome the problem in the prior art that the torque cannot be reduced in a timely and effective manner, thereby failing to protect the vehicle power system and affecting the driving experience.

[0006] In a first aspect, an embodiment of the present application provides a motor protection device, including: a controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits, and three first resistors;

[0007] The three-phase bridge rectifier circuit comprises three first IGBTs of upper bridge arms and three second IGBTs of lower bridge arms, the collector of each first IGBT of the upper bridge arm is respectively connected to one end of the bus capacitor, the source of each first IGBT of the upper bridge arm is respectively connected to the collector of each second IGBT of the lower bridge arm and the motor, the emitter of each second IGBT of the lower bridge arm is respectively connected to the first end of each switching circuit, the second end of each switching circuit is respectively connected to one end of each corresponding first resistor, and the other end of each first resistor is connected to the other end of the bus capacitor;

[0008] Wherein, the gate of the first IGBT of each upper bridge arm and the third end of each switching circuit are respectively connected to the controller through a driver to receive a control signal sent by the controller;

[0009] The bus capacitor is used for voltage stabilization, and the first resistor is used for voltage division;

[0010] The controller is used to send a control signal to the driver to control the on / off state of each branch in the three-phase bridge rectifier circuit and / or the switching circuit;

[0011] The driver is used to apply voltage to the gate of the first IGBT and / or the gate of the second IGBT and provide driving current by receiving a control signal sent by the controller, so as to control the on / off state of the first IGBT and / or the second IGBT; the driver is also used to switch the switching circuit to a preset branch by receiving a control signal sent by the controller, and the preset branch is used for current shunting and voltage division;

[0012] The three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor; the three-phase bridge rectifier circuit is also used to support active short-circuit operation;

[0013] The switching circuit is used to switch to a preset branch according to a control signal received from the controller when the bus capacitor is quickly discharged or when an active short-circuit operation is performed, so as to protect the motor.

[0014] In a possible design, the control signal includes a shutdown instruction, and the switching circuit includes: a second resistor and a switch, the switch includes a MOS tube, and the second resistor and the MOS tube are connected in parallel;

[0015] The drain of the MOS tube is the first end of the switching circuit, the source of the MOS tube is the second end of the switching circuit, the gate of the MOS tube is the third end of the switching circuit, and the gate of the MOS tube is connected to the signal line of the controller through a driver;

[0016] The driver is also used to apply voltage to the gate of the MOS tube and provide driving current by receiving a control signal sent by the controller, so as to control the on-off state of the MOS tube; the switching circuit is also used to execute the operation of shutting down the MOS tube according to the shutdown instruction sent by the controller;

[0017] The second resistor is greater than the first resistor.

[0018] In a possible design, if the controller detects that the first IGBTs of the three upper bridge arms are all at a low level, the MOS tubes in the three switching circuits are controlled to be disconnected at the same time to switch to the branch where the second resistor is located in the three switching circuits.

[0019] In a possible design, the controller is further used to detect whether there is a need for active short circuit or a need for rapid discharge;

[0020] Accordingly, when a vehicle equipped with the motor fails during operation and cannot be driven, it is determined that there is a need for active short circuiting;

[0021] When the vehicle is under high voltage, it is determined that there is a need for rapid discharge.

[0022] In a possible design, if there is a need for active short circuit, the first IGBT of the three upper bridge arms is turned off, and the second IGBT of the three lower bridge arms is turned on at the same time, or the first IGBT of the three upper bridge arms is turned on, and the second IGBT of the three lower bridge arms is turned off at the same time, and a shutdown instruction is sent to each of the MOS tubes through the controller, and each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction.

[0023] In one possible design, if there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and at the same time, a shutdown instruction is sent to the corresponding MOS tube through the controller to allow current to flow through the corresponding second resistor.

[0024] In a second aspect, an embodiment of the present application provides a motor protection method, which is applied to the motor protection device as described in any one of the first aspects, and the method includes:

[0025] The controller detects whether there is a need for active short circuit or rapid discharge;

[0026] If there is a need for active short circuit or rapid discharge, the controller sends a shut-down instruction to the switch of the switching circuit in the motor protection device to switch the switching circuit to the preset branch.

[0027] In a possible design, the switch includes a MOS tube; if there is a need for active short circuit or rapid discharge, the controller sends a shutdown instruction to the switch of the switching circuit in the motor protection device to switch the switching circuit to the preset branch, including:

[0028] If there is a need for active short circuit, the controller controls to turn off the first IGBTs of the three upper bridge arms and turn on the second IGBTs of the three lower bridge arms at the same time, or turns on the first IGBTs of the three upper bridge arms and turns off the second IGBTs of the three lower bridge arms at the same time, and the controller sends a shutdown instruction to each of the MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction;

[0029] If there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and at the same time, the controller sends shutdown instructions to the corresponding MOS tubes respectively, so that each MOS tube disconnects the corresponding MOS tube according to the received shutdown instructions.

[0030] In one possible design, the method further includes:

[0031] If the controller detects that the first IGBTs of the three upper bridge arms are all at low level, the controller controls the MOS tubes in the three switching circuits to be disconnected at the same time to switch to the preset branch.

[0032] In a possible design, the controller detects whether there is a need for active short circuit or rapid discharge, including:

[0033] When the controller detects that a vehicle equipped with the motor fails during operation and cannot be driven, the controller determines that there is a need for active short circuit;

[0034] The controller determines that there is a need for rapid discharge when it detects that the vehicle is under high voltage.

[0035] The motor protection device and method provided by the embodiment of the present application are provided with a controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits and three first resistors; the three-phase bridge rectifier circuit includes three first IGBTs of upper bridge arms and three second IGBTs of lower bridge arms, the collector of each first IGBT of the upper bridge arm is respectively connected to one end of the bus capacitor, the source of each first IGBT of the upper bridge arm is respectively connected to the collector of each second IGBT of the lower bridge arm and the motor, the emitter of each second IGBT of the lower bridge arm is respectively connected to the first end of each switching circuit, the second end of each switching circuit is respectively connected to one end of the corresponding first resistor, and the other end of each first resistor is connected to the other end of the bus capacitor; wherein the gate of each first IGBT of the upper bridge arm and the third end of each switching circuit are respectively connected to the controller through the driver for receiving the control signal sent by the controller; the bus capacitor is used for voltage stabilization, and the first resistor is used for voltage division; the controller is used to send a control signal to the driver for controlling The driver is used to apply voltage to the gate of the first IGBT and / or the gate of the second IGBT and provide drive current by receiving the control signal sent by the controller to control the on-off state of the first IGBT and / or the second IGBT; the driver is also used to switch the switching circuit to a preset branch by receiving the control signal sent by the controller; the three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor; the three-phase bridge rectifier circuit is also used to support the operation of active short circuit; the switching circuit is used to switch to the preset branch according to the control signal of the controller received when the bus capacitor is quickly discharged or when the active short circuit operation is performed, so as to protect the motor, realize reliable bus capacitor fast discharge, the current does not pass through the motor winding, and no torque is generated. At the same time, the active short circuit function is also provided, which reduces the motor short circuit current and reduces the heat generated by the motor winding, reduces the torque impact when the active short circuit is turned on, improves driving comfort, and protects the vehicle power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0037] Figure 1 A schematic diagram of a motor protection device provided in an embodiment of the present application;

[0038] Figure 2 A schematic diagram of a motor protection device provided in yet another embodiment of the present application;

[0039] Figure 3 A schematic diagram of a switching circuit provided in yet another embodiment of the present application;

[0040] Figure 4 A schematic diagram of a flow chart of a motor protection method provided in an embodiment of the present application;

[0041] Figure 5 A schematic diagram of the structure of a motor protection system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0043] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] At present, the discharge method through the motor winding needs to be calibrated and modulated, and the electric drive system is not completely decoupled, resulting in torque generation; and once an IGBT fails, it cannot be discharged, which will bring unexpected torque. Therefore, the existing technology cannot reduce the torque in a timely and effective manner, and thus cannot protect the vehicle power system, and affects the driving experience.

[0045] In order to solve the above problems, the technical concept of the present application is to set up a switching circuit composed of a switch and a resistor. According to the actual working conditions, the switches in the switching circuit can be controlled to select whether to always go through the branch where the resistor is located. Through modulation, the output torque in the active short-circuit state can be controlled, which can effectively reduce the short-circuit current of the winding, and at the same time reduce the amplitude of the transient current to avoid overcurrent and overheating; and a three-phase bridge rectifier circuit is also provided. During rapid discharge, the upper and lower IGBTs of any one, two or three phases in the three-phase bridge arm can be directly connected to realize rapid discharge of the bus capacitor. At this time, a switch shutdown command in the switching circuit is sent, and the discharge current flows through the large resistance in the switching circuit, and the current will not pass through the motor winding, and no torque is generated, thereby improving driving comfort and protecting the vehicle power system.

[0046] In practical applications, see Figure 1 , Figure 1 A schematic diagram of a motor protection device provided in an embodiment of the present application. The motor protection device can be applied to vehicle usage scenarios. The motor protection device includes a controller 11, a driver 21, a three-phase bridge rectifier circuit 31, a bus capacitor C1, three switching circuits 41, and three first resistors R1. The three-phase bridge rectifier circuit 31 includes three first IGBTs (i.e., G1, G2, and G3) of the upper bridge arms and three second IGBTs (i.e., G4, G5, and G6) of the lower bridge arms. The collector of the first IGBT of each upper bridge arm is respectively connected to one end of the bus capacitor, and the source of the first IGBT of each upper bridge arm is respectively connected to the collector of the second IGBT of each lower bridge arm and the motor (the motor here can be a three-phase AC motor, i.e., M). The emitter of the second IGBT of each lower bridge arm is respectively connected to the first end of each switching circuit, and the second end of each switching circuit is respectively connected to one end of the corresponding first resistor R1, and the other end of each first resistor R1 is connected to the other end of the bus capacitor C1. Among them, a large resistor R can be connected in parallel at both ends of the bus capacitor C1. BL It is used for slow discharge of motor controller (i.e. controller).

[0047] The three switching circuits here are composed of switches (the switches here can be MOS tubes, namely S1, S2, S3) and large resistance (ie R2), and the switches are in a normally on state, and can switch the circuit by turning on and off. Among them, R2>>R1. When S1, S2, S3 are on, the current does not pass through R2.

[0048] The specific implementation process can be:

[0049] 1) When it is detected that G1, G2, and G3 are all at low level (the upper three bridges are closed), S1, S2, and S3 are automatically disconnected at the same time, and the current passes through R2;

[0050] 2) When a shutdown command is received, S1, S2 and S3 can be disconnected respectively according to the command.

[0051] Therefore, the above-mentioned device can realize reliable rapid discharge of bus capacitors. The current does not pass through the motor windings and no torque is generated. At the same time, it also provides an active short-circuit function, which reduces the motor short-circuit current and heat generated by the motor windings, reduces the torque impact when the active short-circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0052] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0053] Figure 2 A schematic diagram of a motor protection device provided in another embodiment of the present application is shown in FIG. Figure 2 As shown, the motor protection device may include: a controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits and three first resistors.

[0054] Wherein, the three-phase bridge rectifier circuit includes three first IGBTs of upper bridge arms and three second IGBTs of lower bridge arms, the collector of each first IGBT of the upper bridge arm is respectively connected to one end of the bus capacitor, the source of each first IGBT of the upper bridge arm is respectively connected to the collector of each second IGBT of the lower bridge arm and the motor, the emitter of each second IGBT of the lower bridge arm is respectively connected to the first end of each switching circuit, the second end of each switching circuit is respectively connected to one end of the corresponding first resistor, and the other end of each first resistor is respectively connected to the other end of the bus capacitor; wherein, the gate of each first IGBT of the upper bridge arm and the third end of each switching circuit are respectively connected to the controller through a driver for receiving a control signal sent by the controller.

[0055] Specifically, the bus capacitor is used for voltage stabilization, and the first resistor is used for voltage division.

[0056] The controller is used to send a control signal to the driver to control the on / off state of each branch in the three-phase bridge rectifier circuit and / or the switching circuit.

[0057] The driver is used to apply voltage to the gate of the first IGBT and / or the second IGBT and provide driving current by receiving a control signal sent by the controller to control the on / off state of the first IGBT and / or the second IGBT; the driver is also used to switch the switching circuit to a preset branch by receiving a control signal sent by the controller. The preset branch is used for current shunting and voltage division.

[0058] The three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor; the three-phase bridge rectifier circuit is also used to support active short-circuit operation.

[0059] The switching circuit is used to switch to a preset branch according to a control signal received from the controller when the bus capacitor is quickly discharged or when an active short-circuit operation is performed, so as to protect the motor.

[0060] In this embodiment, combined with Figure 2 As shown, the power supply DC provides power supply, which is connected to both ends of the bus capacitor C1. The bus capacitor C1 is used for voltage stabilization. When there is a discharge demand, the upper and lower IGBTs of any one, two or three phases in the three-phase bridge arm can be directly connected to realize the rapid discharge of the bus capacitor C1. At this time, a shutdown command is sent to the switch in the switching circuit. The discharge current flows through the large resistance in the switching circuit, and the current will not pass through the motor winding, and no torque is generated.

[0061] Specifically, combined Figure 1 As shown, when the vehicle needs to stop during driving, in order to protect the power system, controller, etc., it is necessary to stop the vehicle and lower the high voltage, which can be achieved through rapid discharge: during rapid discharge, direct discharge of bus capacitor C1 can be achieved by directly passing through G1 and G4 and / or directly passing through G2 and G5 and / or directly passing through G3 and G6. At the same time, in order to protect the motor, it is necessary to send the corresponding branch S1 and / or S2 and / or S3 shutdown instructions, and the discharge current flows through the large resistance in the switching circuit, and the current will not pass through the motor winding, and no torque is generated. For example, when directly passing through G1 and G4, a shutdown instruction needs to be sent to S1; when directly passing through G2 and G5, a shutdown instruction needs to be sent to S2; when directly passing through G3 and G6, a shutdown instruction needs to be sent to S3.

[0062] Among them, the three-phase bridge rectifier circuit is used to provide multiple fast discharge channels, and discharge selection can also be performed when there is an IGBT fault. At the same time, according to the actual working conditions, the switches of S1, S2 and S3 can be controlled to choose whether to always go through the R2 branch. Through modulation, the output torque in the active short-circuit state can be controlled.

[0063] The active short circuit here is realized as follows: a three-phase bridge rectifier circuit turns off the upper bridge arm of the IGBT (i.e., G1, G2, G3) and turns on the three tubes of the lower bridge arm (G4, G5, G6); or turns on the upper bridge arm of the IGBT and turns off the three tubes of the lower bridge arm.

[0064] Therefore, compared with the method of discharging through the motor windings, this embodiment does not require calibration or modulation, and there is no problem of torque generation due to incomplete decoupling of the electric drive system; it also provides multiple fast discharge channels, and discharge selection can also be performed when there is an IGBT fault.

[0065] The embodiment of the present application is provided with a controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits and three first resistors; the three-phase bridge rectifier circuit includes three first IGBTs of upper bridge arms and three second IGBTs of lower bridge arms, the collector of each first IGBT of the upper bridge arm is respectively connected to one end of the bus capacitor, the source of each first IGBT of the upper bridge arm is respectively connected to the collector of each second IGBT of the lower bridge arm and the motor, the emitter of each second IGBT of the lower bridge arm is respectively connected to the first end of each switching circuit, the second end of each switching circuit is respectively connected to one end of the corresponding first resistor, and the other end of each first resistor is connected to the other end of the bus capacitor; wherein the gate of each first IGBT of the upper bridge arm and the third end of each switching circuit are respectively connected to the controller through the driver for receiving the control signal sent by the controller; the bus capacitor is used for voltage stabilization, and the first resistor is used for voltage division; the controller is used to send a control signal to the driver to control the three-phase bridge rectifier circuit. The on-off state of each branch in the rectifier circuit and / or the switching circuit; the driver is used to apply voltage to the gate of the first IGBT and / or the gate of the second IGBT and provide a driving current by receiving a control signal sent by the controller to control the on-off state of the first IGBT and / or the second IGBT; the driver is also used to switch the switching circuit to a preset branch by receiving a control signal sent by the controller; the three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor; the three-phase bridge rectifier circuit is also used to support active short-circuit operation; the switching circuit is used to switch to a preset branch according to the control signal of the controller received when quickly discharging the bus capacitor or when performing an active short-circuit operation, so as to protect the motor, realize reliable fast discharge of the bus capacitor, and the current does not pass through the motor winding, and no torque is generated. At the same time, it also provides the function of active short-circuit, reduces the motor short-circuit current and reduces the heat generated by the motor winding, reduces the torque impact when the active short-circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0066] In one possible design, the control signal includes a shutdown instruction, and the switching circuit includes: a second resistor and a switch, the switch includes a MOS tube, and the second resistor and the MOS tube are connected in parallel; the drain of the MOS tube is the first end of the switching circuit, the source of the MOS tube is the second end of the switching circuit, the gate of the MOS tube is the third end of the switching circuit, and the gate of the MOS tube is connected to the signal line of the controller through a driver.

[0067] The driver is further used to apply voltage to the gate of the MOS tube and provide driving current by receiving a control signal sent by the controller to control the on / off state of the MOS tube; the switching circuit is further used to execute the operation of shutting down the MOS tube according to the received shut-down instruction sent by the controller. The switch here includes but is not limited to the MOS tube.

[0068] In this embodiment, see Figure 3 The schematic diagram of the switching circuit shown in the figure takes S1 as an example and combines Figure 1 and 2 As shown, for each switching circuit, the drain of the MOS tube (i.e., S1, S2, S3) is connected to one end of the second resistor R2, and the source of the MOS tube is connected to the other end of the second resistor R2. The MOS tube here is in a normally on state. Among them, the controller is used to send a shutdown instruction to the MOS tube of the switching circuit, so that the switching circuit switches to the preset branch, i.e., the branch with a large resistance (i.e., the second resistance R2), and the circuit can realize the switching of the emitter (or source) branch by switching. The second resistance R2 here is much larger than the first resistance R1.

[0069] In a possible design, if the controller detects that the first IGBTs of the three upper bridge arms are all at a low level, the MOS tubes in the three switching circuits are controlled to be disconnected at the same time to switch to the branch where the second resistor is located in the three switching circuits.

[0070] In this embodiment, the controller detects the on-off state of the three-phase bridge rectifier circuit in real time. If it is detected that the first IGBTs of the three upper bridge arms are all at a low level, in order to avoid excessive current in the motor winding caused by a short circuit, a control signal, such as a high-level or low-level signal, can be sent to the driver. The driver applies a voltage to the MOS tubes in the three switching circuits to instruct the three MOS tubes to be disconnected at the same time, and then switch to the branch where the second resistor R2 is located, that is, the preset branch. Since the second resistor R2 is cut in to increase the resistance of the circuit, it can effectively reduce the short-circuit current of the winding, and at the same time reduce the amplitude of the transient current to avoid overcurrent and overheating.

[0071] In a possible design, this embodiment provides a detailed description of the controller based on the above embodiment. The controller is also used to detect whether there is a need for active short circuit or rapid discharge; accordingly, when a vehicle equipped with the motor fails during operation and cannot be driven, it is determined that there is a need for active short circuit; when the vehicle is under high voltage, it is determined that there is a need for rapid discharge.

[0072] In this embodiment, when the vehicle is driving or running, multiple different working conditions may occur or be required, such as parking, high voltage, sudden power failure, etc. In order to protect the motor and the controller, the controller needs to send corresponding instructions to reduce the occurrence of faults.

[0073] Specifically, when the controller detects that a vehicle equipped with a motor fails during operation and cannot be driven, it is determined that there is a need for active short circuit; when the controller detects that the vehicle is under high voltage, it is determined that there is a need for rapid discharge.

[0074] In a possible design, this embodiment, based on the above embodiment, describes in detail the scenario of active short circuit. If there is a need for active short circuit, the first IGBT of the three upper bridge arms is turned off, and the second IGBT of the three lower bridge arms is turned on at the same time, or the first IGBT of the three upper bridge arms is turned on, and the second IGBT of the three lower bridge arms is turned off at the same time, and a shutdown instruction is sent to each MOS tube through the controller, and each MOS tube disconnects the corresponding MOS tube according to the received shutdown instruction.

[0075] Specifically, during active short circuit, the controller sends a shutdown command to the three-phase bridge rectifier circuit through the driver, that is, sends a shutdown command (or disconnection command) to G1, G2, and G3 and sends an opening command to G4, G5, and G6, or sends an opening command to G1, G2, and G3 and sends a shutdown command (or disconnection command) to G4, G5, and G6; at the same time, sends a shutdown command to S1, S2, and S3. Therefore, the vehicle needs to actively short-circuit. According to the actual working conditions, the switches of S1, S2, and S3 can be controlled to choose whether to always go through the R2 branch. Through modulation, the output torque in the active short-circuit state can be controlled. During active short circuit, the resistance of the circuit is increased due to the cutting-in of R2, which can effectively reduce the short-circuit current of the winding, and at the same time reduce the amplitude of the transient current to avoid overcurrent and overheating.

[0076] In a possible design, this embodiment provides a detailed description of the fast discharge scenario based on the above embodiment. If there is a need for fast discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and a shutdown instruction is sent to the corresponding MOS tube through the controller to make the current flow through the corresponding second resistor.

[0077] In this embodiment, when the vehicle is parked and under high voltage conditions, rapid discharge is required. The upper and lower IGBTs of any one, two or three phases in the three-phase bridge arm can achieve rapid discharge of the bus capacitor C1. At this time, a shutdown command is sent to S1, S2 or S3, and the discharge current flows through R2 with a large resistance value. The current will not pass through the motor winding, and no torque is generated, thereby protecting the motor.

[0078] Therefore, the circuit protection device provided by the present application does not require calibration, modulation, and there is no phenomenon of torque generation due to incomplete decoupling of the electric drive system; at the same time, multiple fast discharge channels are provided, and discharge selection can also be performed when there is an IGBT failure. Among them, the resistance is controllable, which is convenient for selecting whether to conduct according to the working conditions, and does not affect the normal operation of the original system. It can achieve reliable fast discharge of the bus capacitor, the current does not pass through the motor winding, and no torque is generated. At the same time, it also provides an active short-circuit function, which reduces the motor short-circuit current and reduces the heat generated by the motor winding, reduces the torque impact when the active short circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0079] See also Figure 4 , Figure 4 A schematic flow chart of a motor protection method provided in an embodiment of the present application; the method is applied to the motor protection device described in the above embodiment. The method comprises:

[0080] S401, the controller detects whether there is a need for active short circuit or rapid discharge;

[0081] S402: If there is a need for active short circuit or rapid discharge, a controller sends a shut-down instruction to a switch of a switching circuit in the motor protection device, so that the switching circuit switches to the preset branch.

[0082] In this embodiment, the controller is used as the execution body. In order to control the current not to pass through the motor winding or reduce the current passing through the motor winding, active short circuit or rapid discharge can be achieved according to specific working conditions.

[0083] Specifically, combined Figure 1 As shown, the controller can determine whether there is a need for active short circuit or rapid discharge by receiving preset instructions. When there is a need for discharge, the upper and lower IGBTs of any one, two or three phases in the three-phase bridge arm can be directly connected to achieve rapid discharge of the bus capacitor C1. At this time, a shutdown instruction is sent to the switch in the switching circuit, and the discharge current flows through the large resistance in the switching circuit, and the current does not pass through the motor winding, and no torque is generated.

[0084] If there is a need for active short circuit, the first IGBTs of the three upper bridge arms are turned off and the second IGBTs of the three lower bridge arms are turned on at the same time, or the first IGBTs of the three upper bridge arms are turned on and the second IGBTs of the three lower bridge arms are turned off at the same time, and a shutdown instruction is sent to each MOS tube through the controller, and each MOS tube disconnects the corresponding MOS tube according to the received shutdown instruction.

[0085] The motor protection method provided in this embodiment uses a controller to timely detect whether there is a need for active short circuit or rapid discharge. If so, the controller sends a shutdown command to the MOS tube of the switching circuit in the motor protection device to switch the switching circuit to the preset branch to protect the motor and achieve reliable rapid discharge of the bus capacitor. The current does not pass through the motor winding and does not generate torque. At the same time, it also provides an active short-circuit function, which reduces the motor short-circuit current and heat generated by the motor winding, reduces the torque impact when the active short circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0086] In a possible design, this embodiment describes S402 in detail based on the above embodiment. The switch includes a MOS tube; if there is a need for active short circuit or rapid discharge, the controller sends a shutdown instruction to the switch of the switching circuit in the motor protection device to switch the switching circuit to the preset branch, which can be achieved by the following steps:

[0087] If there is a need for active short circuit, the controller controls to turn off the first IGBT of the three upper bridge arms and turn on the second IGBT of the three lower bridge arms at the same time, or turns on the first IGBT of the three upper bridge arms and turns off the second IGBT of the three lower bridge arms at the same time, and the controller sends a shutdown instruction to each of the MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction; if there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and the controller sends a shutdown instruction to the corresponding MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction.

[0088] In this embodiment, combined with Figure 1 As shown, when actively short-circuited, the controller sends a shutdown command to the three-phase bridge rectifier circuit through the driver, that is, sends a shutdown command (or disconnection command) to G1, G2, and G3 and sends an opening command to G4, G5, and G6, or sends an opening command to G1, G2, and G3 and sends a shutdown command (or disconnection command) to G4, G5, and G6; at the same time, sends a shutdown command to S1, S2, and S3. Therefore, the vehicle needs to be actively short-circuited. According to the actual working conditions, the switches of S1, S2, and S3 can be controlled to choose whether to always go through the R2 branch. Through modulation, the output torque in the active short-circuit state can be controlled. When actively short-circuited, the resistance of the circuit is increased due to the cutting-in of R2, which can effectively reduce the short-circuit current of the winding, and at the same time reduce the amplitude of the transient current to avoid overcurrent and overheating.

[0089] In addition, when the vehicle is parked and under high voltage conditions, rapid discharge is required. The upper and lower IGBTs of any one, two, or three phases in the three-phase bridge arm can achieve rapid discharge of the bus capacitor C1. At this time, a shutdown command is sent to S1, S2, or S3, and the discharge current flows through R2 with a large resistance value. The current will not pass through the motor winding, and no torque is generated, thereby protecting the motor.

[0090] In a possible design, this embodiment provides a detailed description of the motor protection method based on the above embodiment. The method may also include: if the controller detects that the first IGBTs of the three upper bridge arms are all at a low level, controlling the MOS tubes in the three switching circuits to be disconnected at the same time to switch to the preset branch.

[0091] In this embodiment, the controller detects the on-off state of the three-phase bridge rectifier circuit in real time. If it is detected that the first IGBTs of the three upper bridge arms are all at a low level, in order to avoid excessive current in the motor winding caused by a short circuit, a control signal, such as a high-level or low-level signal, can be sent to the driver. The driver applies a voltage to the MOS tubes in the three switching circuits to instruct the three MOS tubes to be disconnected at the same time, and then switch to the branch where the second resistor R2 is located, that is, the preset branch. Since the second resistor R2 is cut in to increase the resistance of the circuit, it can effectively reduce the short-circuit current of the winding, and at the same time reduce the amplitude of the transient current to avoid overcurrent and overheating.

[0092] In a possible design, this embodiment describes S401 in detail based on the above embodiment. The controller detects whether there is a need for active short circuit or fast discharge, which can be achieved by the following steps:

[0093] When the controller detects that a vehicle equipped with the motor fails during operation and cannot be driven, it determines that there is a need for active short circuit; when the controller detects that the vehicle is under high voltage, it determines that there is a need for rapid discharge.

[0094] In this embodiment, when the vehicle is driving or running, multiple different working conditions may occur or be required, such as parking, high voltage, sudden power failure, etc. In order to protect the motor and the controller, the controller needs to send corresponding instructions to reduce the occurrence of faults.

[0095] Specifically, when the controller detects that a vehicle equipped with a motor fails during operation and cannot be driven, it is determined that there is a need for active short circuit; when the controller detects that the vehicle is under high voltage, it is determined that there is a need for rapid discharge.

[0096] Therefore, the circuit protection method provided by the present application does not require calibration, modulation, and there is no phenomenon of torque generation due to incomplete decoupling of the electric drive system; at the same time, multiple fast discharge channels are provided, and discharge selection can also be performed when there is an IGBT failure. Among them, the resistance is controllable, which is convenient for selecting whether to conduct according to the working conditions, and does not affect the normal operation of the original system. It can achieve reliable fast discharge of the bus capacitor, the current does not pass through the motor winding, and no torque is generated. At the same time, it also provides an active short-circuit function, which reduces the motor short-circuit current and reduces the heat generated by the motor winding, reduces the torque impact when the active short circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0097] In order to implement the motor protection method, this embodiment provides a motor protection system. Figure 5 , Figure 5 A schematic diagram of the structure of a motor protection system provided in an embodiment of the present application; the motor protection system 50 comprises: a detection module 501 and a control module 502; the detection module 501 is used to detect whether there is a need for active short circuit or rapid discharge; the control module is used to send a shutdown command to the switch of the switching circuit in the motor protection device when there is a need for active short circuit or rapid discharge, so that the switching circuit switches to the preset branch.

[0098] In this embodiment, a detection module 501 and a control module 502 are provided to detect whether there is a need for active short circuit or rapid discharge. When there is a need for active short circuit or rapid discharge, a shutdown command is sent to the switch of the switching circuit in the motor protection device to switch the switching circuit to the preset branch to protect the motor and achieve reliable rapid discharge of the bus capacitor. The current does not pass through the motor winding and no torque is generated. At the same time, an active short circuit function is also provided, which reduces the motor short circuit current and the heat generated by the motor winding, reduces the torque impact when the active short circuit is turned on, improves driving comfort, and protects the vehicle power system.

[0099] The system provided in this embodiment can be used to execute the technical solution of the above method embodiment. Its implementation principle and technical effects are similar and will not be described in detail in this embodiment.

[0100] In one possible design, the switch includes a MOS tube; a control module, which is specifically used to: when there is a need for active short circuit, control the shutdown of the three first IGBTs of the upper bridge arms and simultaneously turn on the three second IGBTs of the lower bridge arms, or turn on the three first IGBTs of the upper bridge arms and simultaneously shut down the three second IGBTs of the lower bridge arms, and the controller sends a shutdown instruction to each of the MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction; when there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and a shutdown instruction is sent to the corresponding MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction.

[0101] In one possible design, the motor protection system also includes a processing module; the processing module is used to control the MOS tubes in the three switching circuits to be disconnected at the same time when it is detected that the first IGBTs of the three upper bridge arms are all at a low level, so as to switch to the preset branch.

[0102] In one possible design, the detection module is specifically used to: determine the need for active short circuit when it is detected that a vehicle equipped with the motor fails during operation and cannot be driven; and determine the need for rapid discharge when it is detected that the vehicle is under high voltage.

[0103] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the motor protection method as described above is implemented.

[0104] An embodiment of the present application further provides a computer program product, including a computer program, which implements the motor protection method as described above when executed by a processor.

[0105] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms. In addition, each functional module in each embodiment of the present application can be integrated into a processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The unit composed of the above modules can be implemented in the form of hardware or in the form of hardware plus software functional units.

[0106] The above-mentioned integrated module implemented in the form of a software function module can be stored in a computer-readable storage medium. The above-mentioned software function module is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the method described in each embodiment of the present application. It should be understood that the above-mentioned processor can be a central processing unit (English: Central Processing Unit, referred to as: CPU), or other general-purpose processors, digital signal processors (English: Digital Signal Processor, referred to as: DSP), application-specific integrated circuits (English: Application Specific Integrated Circuit, referred to as: ASIC), etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in conjunction with the invention can be directly embodied as a hardware processor to be executed, or the hardware and software modules in the processor can be combined and executed.

[0107] The memory may include high-speed RAM memory, and may also include non-volatile storage NVM, such as at least one disk memory, and may also be a USB flash drive, a mobile hard disk, a read-only memory, a disk or an optical disk, etc. The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of the present application is not limited to only one bus or one type of bus. The above-mentioned storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, a disk or an optical disk. The storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0108] An exemplary storage medium is coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the storage medium can also exist as discrete components in an electronic device or a main control device.

[0109] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A motor protection device, characterized in that: include: A controller, a driver, a three-phase bridge rectifier circuit, a bus capacitor, three switching circuits and three first resistors; The three-phase bridge rectifier circuit comprises three first IGBTs of upper bridge arms and three second IGBTs of lower bridge arms, the collector of each first IGBT of the upper bridge arm is respectively connected to one end of the bus capacitor, the source of each first IGBT of the upper bridge arm is respectively connected to the collector of each second IGBT of the lower bridge arm and the motor, the emitter of each second IGBT of the lower bridge arm is respectively connected to the first end of each switching circuit, the second end of each switching circuit is respectively connected to one end of each corresponding first resistor, and the other end of each first resistor is connected to the other end of the bus capacitor; Wherein, the gate of the first IGBT of each upper bridge arm and the third end of each switching circuit are respectively connected to the controller through a driver to receive a control signal sent by the controller; The bus capacitor is used for voltage stabilization, and the first resistor is used for voltage division; The controller is used to send a control signal to the driver to control the on / off state of each branch in the three-phase bridge rectifier circuit and / or the switching circuit; The driver is used to apply voltage to the gate of the first IGBT and / or the gate of the second IGBT and provide driving current by receiving a control signal sent by the controller, so as to control the on / off state of the first IGBT and / or the second IGBT; the driver is also used to switch the switching circuit to a preset branch by receiving a control signal sent by the controller, and the preset branch is used for current shunting and voltage division; The three-phase bridge rectifier circuit is used to quickly discharge the bus capacitor; the three-phase bridge rectifier circuit is also used to support active short-circuit operation; The switching circuit is used to switch to a preset branch according to a control signal received from the controller when the bus capacitor is rapidly discharged or when an active short-circuit operation is performed, so as to protect the motor; The control signal includes a shutdown instruction, the switching circuit includes: a second resistor and a switch, the switch includes a MOS tube, and the second resistor and the MOS tube are connected in parallel; The drain of the MOS tube is the first end of the switching circuit, the source of the MOS tube is the second end of the switching circuit, the gate of the MOS tube is the third end of the switching circuit, and the gate of the MOS tube is connected to the signal line of the controller through a driver; The driver is also used to apply voltage to the gate of the MOS tube and provide driving current by receiving a control signal sent by the controller, so as to control the on-off state of the MOS tube; the switching circuit is also used to execute the operation of shutting down the MOS tube according to the shutdown instruction sent by the controller; The second resistor is greater than the first resistor.

2. The motor protection device according to claim 1, characterized in that: If the controller detects that the first IGBTs of the three upper bridge arms are all at low level, the MOS tubes in the three switching circuits are controlled to be disconnected at the same time to switch to the branch where the second resistor is located in the three switching circuits.

3. The motor protection device according to claim 2, characterized in that: The controller is also used to detect whether there is a need for active short circuit or rapid discharge; Accordingly, when a vehicle equipped with the motor fails during operation and cannot be driven, it is determined that there is a need for active short circuiting; When the vehicle is under high voltage, it is determined that there is a need for rapid discharge.

4. The motor protection device according to claim 3, characterized in that: If there is a need for active short circuit, the first IGBTs of the three upper bridge arms are turned off and the second IGBTs of the three lower bridge arms are turned on at the same time, or the first IGBTs of the three upper bridge arms are turned on and the second IGBTs of the three lower bridge arms are turned off at the same time, and a shutdown instruction is sent to each MOS tube through the controller, and each MOS tube disconnects the corresponding MOS tube according to the received shutdown instruction.

5. The motor protection device according to claim 3 or 4, characterized in that: If there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and at the same time, a shutdown instruction is sent to the corresponding MOS tube through the controller to allow current to flow through the corresponding second resistor.

6. A motor protection method, characterized in that: Applied to the motor protection device according to any one of claims 1 to 5, the method comprises: The controller detects whether there is a need for active short circuit or rapid discharge; If there is a need for active short circuit or rapid discharge, the controller sends a shut-down instruction to the switch of the switching circuit in the motor protection device to switch the switching circuit to the preset branch.

7. The motor protection method according to claim 6, characterized in that: The switch includes a MOS tube; if there is a need for active short circuit or rapid discharge, the controller sends a shutdown instruction to the switch tube of the switching circuit in the motor protection device to switch the switching circuit to the preset branch, including: If there is a need for active short circuit, the controller controls to turn off the first IGBTs of the three upper bridge arms and turn on the second IGBTs of the three lower bridge arms at the same time, or turns on the first IGBTs of the three upper bridge arms and turns off the second IGBTs of the three lower bridge arms at the same time, and the controller sends a shutdown instruction to each of the MOS tubes respectively, so that each of the MOS tubes disconnects the corresponding MOS tube according to the received shutdown instruction; If there is a need for rapid discharge, the bus capacitor is quickly discharged through a group of IGBTs of at least one phase in the three-phase bridge rectifier circuit, and at the same time, the controller sends shutdown instructions to the corresponding MOS tubes respectively, so that each MOS tube disconnects the corresponding MOS tube according to the received shutdown instructions.

8. The motor protection method according to claim 7, characterized in that: The method further comprises: If the controller detects that the first IGBTs of the three upper bridge arms are all at low level, the controller controls the MOS tubes in the three switching circuits to be disconnected at the same time to switch to the preset branch.

9. The motor protection method according to claim 7 or 8, characterized in that: The controller detects whether there is a need for active short circuit or rapid discharge, including: When the controller detects that a vehicle equipped with the motor fails during operation and cannot be driven, the controller determines that there is a need for active short circuit; The controller determines that there is a need for rapid discharge when it detects that the vehicle is under high voltage.

Images