Electric drive system, electric drive system control method and device and electric drive system controller

Abstract

The invention provides an electric drive system, an electric drive system control method and device and an electric drive system controller, and relates to the technical field of electric drive systems, the electric drive system comprises an inverter, a capacitor, a protection device and a motor; wherein the protection device is connected between the bus positive wire harness and the bus negative wire harness, and the capacitor is connected with the protection device in parallel; wherein the first withstand voltage threshold value of the protection device is greater than the maximum counter electromotive force of the motor or the normal working voltage of the power supply device, and the first withstand voltage threshold value is smaller than the withstand voltage values of all high-voltage devices in the electric drive system, so that under the condition that the original ASC path fails, when the electric drive system is abnormal, a new ASC path is established, and the normal working condition of the electric drive system is ensured. And the driving safety is improved, and the maintenance cost is reduced while the power supply and the inverter are protected from being damaged.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive systems, and in particular to an electric drive system, an electric drive system control method and device, and an electric drive system controller. Background Art

[0002] The main function of a vehicle's electric drive system is to convert the electrical energy of the power supply device into mechanical energy to drive the vehicle. If the electric drive system fails when the motor is running at high speed, it will form a short-circuit path, namely the ASC (Active short circuit) path, by controlling the switching tube in the inverter to protect the high-voltage devices and motors in the electric drive system.

[0003] However, when a driver chip fails, it may result in the inability to form an ASC path by driving the switch tubes of the upper and lower bridge arms in the inverter to turn on or off, that is, the ASC path fails. In the related art, an AC side circuit breaker is added, and the AC side circuit breaker is used to disconnect the connection between the inverter and the motor in the electric drive system after the ASC path fails to avoid damage to the power supply and the inverter. However, the inverter and the motor are highly integrated (for example, the two are fixedly connected by welding), and due to installation space and cost limitations, the AC side circuit breaker is usually designed as a disposable structure, which causes irreversible damage to the connection structure between the inverter and the motor when the AC side circuit breaker is triggered. Subsequently, the inverter and the motor need to be disassembled and the inverter and the motor need to be reconnected, which leads to high maintenance costs. Summary of the invention

[0004] The problem solved by the present invention is how to protect the power supply and the inverter from being damaged while reducing the maintenance cost when the ASC path fails.

[0005] In order to solve the above problems, the present invention provides an electric drive system, an electric drive system control method and device, and an electric drive system controller.

[0006] In a first aspect, the present invention provides an electric drive system, which is connected to a power supply device through a bus positive wiring harness and a bus negative wiring harness,

[0007] The electric drive system includes: inverter, capacitor, protection device and motor;

[0008] The protection device is connected between the bus positive wiring harness and the bus negative wiring harness, the capacitor is connected in parallel with the protection device, the first end of the inverter is connected to the bus positive wiring harness, the second end of the inverter is connected to the bus negative wiring harness, and the third end of the inverter is connected to the input end of the motor;

[0009] Among them, the first withstand voltage threshold of the protection device is greater than the maximum back electromotive force of the motor or the normal operating voltage of the power supply device, and the first withstand voltage threshold is less than the withstand voltage value of all high-voltage devices in the electric drive system.

[0010] Optionally, the electric drive system also includes a bus switch, wherein the bus switch is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness; or, the bus switch is arranged on the bus negative wiring harness, and the bus switch is located between the negative pole of the power supply device and a second connection point, and the second connection point is the connection point between the protection device and the bus negative wiring harness.

[0011] Optionally, the electric drive system also includes a fuse, wherein the fuse is connected in series with the protection device, and when the positive electrode of the power supply device, the bus positive wiring harness, the fuse, the protection device, the bus negative wiring harness and the negative electrode of the power supply device form a short circuit, the fuse blows within a preset time period.

[0012] In a second aspect, the present invention provides an electric drive system control method, which is applied to the electric drive system as described above, and the electric drive system control method includes:

[0013] When it is detected that the electric drive system cannot enter the active short-circuit mode, controlling the electric drive system to enter the coasting mode;

[0014] After the electric drive system enters the coasting mode, the electric drive system is controlled to be disconnected from the power supply device or the electric drive system is controlled to be disconnected from the power supply device according to the operation data of the electric drive system.

[0015] Optionally, controlling the electric drive system to be disconnected from the power supply device based on the operating data of the electric drive system includes: after the electric drive system enters the inertial gliding mode, acquiring the operating data of the electric drive system and the allowable charging power of the battery pack in the power supply device; when the allowable charging power is less than a preset power threshold and the operating data is greater than a first threshold, controlling the electric drive system to be disconnected from the power supply device.

[0016] Optionally, the electric drive system is controlled to be disconnected from the power supply device according to the operating data of the electric drive system, including: after the electric drive system enters the inertial gliding mode, obtaining the operating data of the electric drive system; when the operating data is greater than a first threshold, controlling the electric drive system to be disconnected from the power supply device.

[0017] Optionally, the power supply device includes a main relay, the main relay is directly connected to a battery pack in the power supply device, and is connected to the electric drive system through a bus positive wiring harness and a bus negative wiring harness; the controlling the electric drive system to be disconnected from the power supply device includes: controlling the main relay to be disconnected;

[0018] Alternatively, the electric drive system includes a bus switch, which is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness; controlling the electric drive system to disconnect from the power supply device includes: controlling the bus switch to disconnect.

[0019] Optionally, the power supply device also includes a pre-charging relay, and the main relay includes a first main relay and / or a second main relay, two ends of the first main relay are respectively connected to the positive electrode of the battery pack and the positive electrode harness of the bus, two ends of the second main relay are respectively connected to the negative electrode of the battery pack and the negative electrode harness of the bus, and the pre-charging relay is connected in parallel with the first main relay; controlling the main relay to disconnect includes: controlling the pre-charging relay to close; controlling the first main relay and / or the second main relay to disconnect.

[0020] In a third aspect, the present invention provides an electric drive system control device, comprising:

[0021] A first control unit, configured to control the electric drive system to enter a coasting mode when detecting that the electric drive system cannot enter an active short-circuit mode;

[0022] The second control unit is used to control the electric drive system to be disconnected from the power supply device according to the operating state of the electric drive system.

[0023] In a fourth aspect, the present invention provides an electric drive system controller, comprising a memory and a processor;

[0024] The memory is used to store computer programs;

[0025] The processor is used to implement the electric drive system control method as described in the second aspect when executing the computer program.

[0026] In a fifth aspect, the present invention provides a computer-readable storage medium storing a computer program. When the computer program is read and executed by a processor, the electric drive system control method as described in the second aspect is implemented.

[0027] Compared with the prior art, the electric drive system of the present invention has the following beneficial effects: by adding a protection device connected in parallel with the capacitor and the inverter to the electric drive system, the maximum withstand voltage value of the protection device is the first withstand voltage threshold, the first withstand voltage threshold is greater than the maximum back electromotive force or the normal working voltage of the power supply device, and the normal operation of the electric drive system is ensured without faults. In addition, the first withstand voltage threshold is less than the withstand voltage value of all high-voltage devices in the electric drive system, and the protection device will be broken down before other high-voltage devices, and the voltage in the electric drive system will be discharged after the breakdown, which limits the further increase of the voltage, and realizes the protection of the power supply device and the high-voltage devices in the electric drive system. For example: when the ASC path fails, the protection device is broken down when the voltage at both ends of the protection device is greater than the first withstand voltage threshold, and the protection device is turned on at this time, and the electric drive system can form a new ASC circuit through the three-phase winding, upper and lower bridge arms, and the protection device of the motor, so as to realize the discharge of the high voltage of the electric drive system, thereby limiting the further increase of the voltage, improving the driving safety, and realizing the protection of the power supply device and the high-voltage devices in the electric drive system. Compared with the solution of adding an AC side circuit breaker in the related art, the present invention will not cause damage to the connection structure between the inverter and the motor. It is only necessary to replace the protection device after the protection device is broken down to complete the maintenance, thereby reducing the maintenance cost.

[0028] Compared with the prior art, the electric drive system control method of the present invention has the following beneficial effects: when it is detected that the electric drive system cannot enter the active short-circuit mode, the electric drive system is controlled to enter the inertial gliding mode under the safety mode; after entering the inertial gliding mode, in order to protect the power supply device, the electric drive system is directly controlled to be disconnected from the power supply device, or the power supply device and the electric drive system are controlled to be disconnected according to the operating data of the electric drive system; after the electric drive system is disconnected from the power supply device, the electric drive system will not reverse charge the power supply device, thereby protecting the power supply device, and will not generate a large braking torque, thereby avoiding the braking torque generated by uncontrolled rectification and thus safety problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a circuit for connecting an electric drive system and a power supply device in the related art;

[0030] Figure 2 A schematic diagram of a current circuit connecting an electric drive system and a power supply device according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the position of a bus switch according to an embodiment of the present invention;

[0032] Figure 4 Another schematic diagram of the position of a bus switch according to an embodiment of the present invention;

[0033] Figure 5This is another schematic diagram of the position of a bus switch according to an embodiment of the present invention;

[0034] Figure 6 Schematic diagram of a flow chart of an electric drive system control method according to an embodiment of the present invention;

[0035] Figure 7 A schematic diagram of a process of disconnecting an electric drive system from a power supply device according to an embodiment of the present invention;

[0036] Figure 8 A schematic diagram of a process of disconnecting another electric drive system from a power supply device according to an embodiment of the present invention;

[0037] Fig. 9 A schematic diagram of a process of disconnecting an electric drive system from a power supply device according to another embodiment of the present invention;

[0038] Fig.10 A schematic diagram of a process of disconnecting an electric drive system from a power supply device according to another embodiment of the present invention;

[0039] Fig.11 A schematic diagram of the positions of the main relay and the pre-charging relay according to an embodiment of the present invention;

[0040] Fig.12 It is a structural schematic diagram of an electric drive system control device according to an embodiment of the present invention;

[0041] Fig.13 The figure is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0043] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0044] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0045] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0046] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes, and are not used to limit the scope of these messages or information.

[0047] In related technologies, such as Figure 1 As shown, the electric drive system is connected to the power supply device through the bus positive wiring harness and the bus negative positive wiring harness. The electric drive system includes a capacitor and an inverter connected between the bus positive wiring harness and the bus negative wiring harness, and a motor connected to the AC output end of the inverter. When the electric drive system fails when the motor is running at high speed, the ASC path will be formed by controlling the switch tubes of the upper and lower bridge arms in the inverter, that is, entering the active short-circuit mode, and the three-phase winding of the motor will form a short-circuit path through the lower bridge arm switch tube, so that the back electromotive force of the motor is short-circuited, thereby limiting the output torque of the motor.

[0048] In some cases, such as controller failure or communication failure that makes it impossible to drive the switch tubes of the upper and lower bridge arms in the inverter to perform switching operations, and thus the ASC path cannot be formed, when the motor is running at high speed, if a short-circuit path cannot be formed, the voltage may increase and exceed the withstand voltage threshold of the high-voltage components and power supply devices of the electric drive system, thereby damaging the high-voltage components and power supply devices in the electric drive system.

[0049] In the related art, after the ASC path fails, an AC side circuit breaker is used to disconnect the connection between the electric drive system and the motor to avoid damage to the power supply. However, this method will cause irreversible damage to the connection structure between the electric drive system and the motor (such as a three-phase AC wiring harness), and the maintenance cost of reconnecting the inverter and the motor in the electric drive system is high.

[0050] In view of the problems existing in the above-mentioned related technologies, the present embodiment provides an electric drive system, an electric drive system control method and device, and an electric drive system controller.

[0051] like Figure 2 As shown, an electric drive system provided by an embodiment of the present invention is connected to a power supply device through a bus positive wire harness and a bus negative wire harness, and the electric drive system includes:

[0052] Inverters, capacitors, protection devices and motors;

[0053] The protection device is connected between the bus positive wiring harness and the bus negative wiring harness, the capacitor is connected in parallel with the protection device, the first end of the inverter is connected to the bus positive wiring harness, the second end of the inverter is connected to the bus negative wiring harness, and the third end of the inverter is connected to the input end of the motor;

[0054] Among them, the first withstand voltage threshold of the protection device is greater than the maximum back electromotive force of the motor or the normal operating voltage of the power supply device, and the first withstand voltage threshold is less than the withstand voltage value of all high-voltage devices in the electric drive system.

[0055] Specifically, Figure 2 As shown, in addition to the inverter, motor, and capacitor, the electric drive system also includes a newly added protection device, which is connected between the bus positive wiring harness and the bus negative wiring harness, wherein the bus positive wiring harness is a wiring harness connecting the positive pole of the DC power supply (i.e., the power supply device) and the first end of the inverter, and transmits the positive voltage of the power supply device to the inverter, and the bus negative wiring harness is a wiring harness connecting the negative pole of the power supply device and the second end of the inverter, and transmits the negative voltage of the power supply device to the inverter.

[0056] The capacitor is connected between the bus positive wiring harness and the bus negative wiring harness, that is, the capacitor is connected in parallel with the protection device. The first end of the inverter is connected to the bus positive wiring harness, the second end of the inverter is connected to the bus negative wiring harness, and the third end of the inverter is connected to the input end of the motor, wherein the first end and the second end are the DC side of the inverter, and the third end is the AC side of the inverter. When the DC side is the input end, the first end is the positive input end, the second end is the negative input end, and the third end is the AC output end. The inverter converts the DC power provided by the power supply device into the AC power required by the motor. The AC output end of the inverter refers to the port where the inverter outputs AC power, usually with three-phase output (U phase, V phase, W phase), which is used to connect to the input end of the motor to supply the motor operation.

[0057] When the motor in the electric drive system is running at high speed, if the electric drive system fails, an ASC path will be formed by controlling the switch tubes of the upper and lower bridge arms in the inverter. If the ASC path cannot be formed, the electric drive system will be controlled to enter the coasting mode (FW mode, Free-Wheeling). In the coasting mode, the protection device may be over-voltage. For example, in the FW mode and when the motor is running at high speed or when the connection with the power supply device is accidentally interrupted during the operation of the motor, the protection device may be over-voltage, that is, the voltage at both ends of the protection device (corresponding to the bus voltage, that is, the voltage between the positive bus wire harness and the negative bus wire harness) is greater than the first withstand voltage threshold. When the protection device is over-voltage, the protection device is broken down. At this time, the protection device is turned on, and the electric drive system can form a circuit through the three-phase winding, the freewheeling diodes of the upper and lower bridge arms, and the protection device to discharge the high voltage of the electric drive system, thereby limiting the further increase of the voltage and protecting the high-voltage devices in the electric drive system.

[0058] In the inertial gliding mode, the switch tubes of the upper and lower bridge arms of all bridge arms in the inverter are in the disconnected state. Overvoltage of the protection device means that the voltage across the protection device is greater than the first withstand voltage threshold, which is the maximum voltage that the above protection device can withstand. The protection device can be one of a varistor, a transient voltage suppressor diode or a thyristor.

[0059] In addition, the withstand voltage threshold (first withstand voltage threshold) corresponding to the protection device is lower than the withstand voltage value of all high-voltage devices in the electric drive system. Therefore, when the voltage in the electric drive system continues to increase, the protection device will be broken down before other high-voltage devices, and the voltage in the electric drive system will be discharged after the breakdown, thereby limiting the further increase of the voltage and realizing the protection of high-voltage devices in the electric drive system, such as capacitors or high-voltage devices in inverters.

[0060] At the same time, the first withstand voltage threshold is greater than the maximum back electromotive force or the first withstand voltage threshold is greater than the normal operating voltage of the power supply device, ensuring that the electric drive system can work normally when there is no fault. It should be noted that the maximum back electromotive force of the electric drive system is greater than the normal operating voltage of the power supply device.

[0061] There are two sources of voltage that cause overvoltage in the protection device: one is the back electromotive force of high-speed rotation in the inertial gliding mode, and the other is the motor inductance. Due to the characteristic that the current of the inductor cannot change suddenly, when the power supply device and the electric drive system are disconnected, if the current flows from the motor to the positive pole of the battery at this time, the motor winding will induce a very high electromotive force.

[0062] When the first withstand voltage threshold is set to be greater than the normal operating voltage of the power supply device, the protection device will not be broken down during normal operation, ensuring the normal operation of the electric drive system when no fault occurs, and the high voltage generated by the motor inductance and the back electromotive force of the motor rotating at high speed in the coasting mode can be discharged through the protection device; when the first withstand voltage threshold is set to be greater than the maximum back electromotive force, on the basis of the normal operation of the protection device when no fault occurs in the electric drive system, the protection device will not be broken down when the electric drive system is in the FW mode and the power supply device is disconnected from the electric drive system, that is, the electric drive system can operate in the FW mode; at the same time, the high voltage generated by the motor inductance can be discharged through the protection device, and at the same time, the back electromotive force in the coasting mode can be borne by the withstand voltage of the high-voltage device.

[0063] In this embodiment, by adding a protection device in parallel with the capacitor and the inverter to the electric drive system, the maximum withstand voltage value of the protection device is a first withstand voltage threshold, and the first withstand voltage threshold is greater than the maximum back electromotive force or the normal working voltage of the power supply device, thereby ensuring the normal operation of the electric drive system without a fault. In addition, the first withstand voltage threshold is less than the withstand voltage value of all high-voltage devices in the electric drive system. The protection device will be broken down before other high-voltage devices, and the voltage in the electric drive system will be discharged after the breakdown, thereby limiting the further increase of the voltage, thereby realizing the protection of the high-voltage devices in the electric drive system. When the ASC path fails, the protection device is broken down when the voltage at both ends of the protection device is greater than the first withstand voltage threshold. At this time, the protection device is turned on, and the electric drive system can form an ASC circuit through the three-phase winding, upper and lower bridge arms, and protection device of the motor to realize the discharge of the high voltage of the electric drive system, thereby limiting the further increase of the voltage, thereby realizing the protection of the high-voltage devices in the electric drive system. Compared with the solution of adding an AC side circuit breaker in the related art, the present invention does not change the connection structure between the inverter and the motor, and only needs to replace the protection device after the protection device is broken down to complete the maintenance, thereby reducing the maintenance cost.

[0064] In addition, the protection device in this embodiment is a passive protection device, which does not require external energy input (such as low power supply or control signal control, etc.), and can achieve its protection function only through its own characteristics. Therefore, it will not lose its protection effect due to failure of the control signal or power disconnection, thereby improving the reliability of protection of high-voltage devices.

[0065] Optionally, the protection device is covered by a separate cover or housing, in which case the protection device is maintainable and easily replaceable.

[0066] Optionally, the protection device is integrated inside the controller.

[0067] Optionally, the electric drive system also includes a fuse, wherein the fuse is connected in series with the protection device, wherein when the positive electrode of the power supply device, the bus positive wiring harness, the protection device, the fuse, the bus negative wiring harness and the negative electrode of the power supply device form a short circuit, the fuse blows within a preset time period.

[0068] Specifically, a fuse is also installed in the electric drive system, and the fuse is connected in series with the protection device.

[0069] During normal operation, if the protection device fails, the positive electrode of the power supply unit, the positive wiring harness of the busbar, the protection device, the fuse, the negative wiring harness and the negative electrode of the power supply unit will form a short circuit. At this time, the fuse will blow within the specified time to achieve the purpose of protecting the power supply unit.

[0070] Optionally, the fuse also meets the requirement that when the protection device is broken down by overvoltage and there is no external high-voltage power supply (that is, the power supply device and the electric drive system are disconnected), the fuse will not be blown during the process of the voltage in the capacitor and the electric drive winding being discharged to below the safe voltage. That is, when the electric drive system forms an ASC circuit through the three-phase winding, upper and lower bridge arms, fuse, and protection device, the fuse can operate for a long time without being damaged, thereby ensuring that the protection function of the protection device will not fail.

[0071] Optionally, the electric drive system also includes a bus switch, wherein the bus switch is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness.

[0072] Specifically, Figure 3 , Figure 4 as well as Figure 5 As shown in FIG. 1 , in addition to adding a protection device in parallel with the inverter and capacitor in the electric drive system, a bus switch (corresponding to Figure 3-5 The bus switch is arranged on the positive wiring harness of the bus, the bus switch must be before the protection device, and the bus switch can be before or after the capacitor.

[0073] It should be noted that the above “before” refers to the side closer to the positive pole of the power supply device, and “after” refers to the side away from the positive pole of the power supply device.

[0074] The connection point between the protection device and the bus positive wiring harness is recorded as the first connection point (corresponding to Figure 3 , Figure 4 as well as Figure 5The bus switch must be before the protective device, that is, the bus switch is installed before the first connection point, that is, the bus switch is located between the positive pole entrance of the bus positive wiring harness and the first connection point.

[0075] The connection point between the capacitor and the bus positive wiring harness is recorded as the third connection point (corresponding to Figure 3 , Figure 4 as well as Figure 5 When the protection device is before the capacitor, that is, the first connection point A is closer to the positive pole of the power supply device than the third connection point B, corresponding to Figure 3 , in this case, the bus switch can only be set before the protection device and the capacitor. When the protection device is after the capacitor, that is, the first connection point B is closer to the positive pole of the power supply device than the third connection point A, corresponding to Figure 4 and Figure 5 At this time, there are two ways to set the bus switch: (1) corresponding to Figure 4 , the bus switch is set before the protection device and the capacitor; (2) corresponds to Figure 5 The bus switch is set after the capacitor and before the protection device. It should be noted that in this setting position, when the bus switch is disconnected, the protection device cannot discharge the voltage of the capacitor, but the voltage on the capacitor is disconnected from the inverter, and will not be damaged by the voltage caused by the motor's back electromotive force and motor inductance, and the protection of the high-voltage device capacitor can also be achieved.

[0076] Optionally, the bus switch is arranged on the bus negative electrode harness, and the bus switch is located between the negative electrode of the power supply device and a second connection point, and the second connection point is a connection point between the protection device and the bus negative electrode harness.

[0077] Specifically, the bus switch can also be set on the bus positive harness. The bus switch must be before the protective device. The bus switch can be before or after the capacitor. It should be noted that the above "before" refers to the side closer to the negative entrance of the bus negative harness, and "after" refers to the side away from the negative entrance of the bus negative harness. The connection point between the protective device and the bus negative harness is recorded as the second connection point. The bus switch must be before the protective device, that is, the bus switch is installed before the first connection point, that is, the bus switch is located between the positive entrance of the bus negative harness and the first connection point. The setting position of the bus switch on the bus negative harness is similar to the setting position of the bus switch on the bus positive harness.

[0078] It should be noted that Figure 1-Figure 5 The DCDC device in the circuit is a transformer device, which is used to provide low-voltage power to low-voltage loads, such as providing 12V voltage to lighting systems, car audio systems, etc.

[0079] like Figure 6 As shown, an embodiment of the present invention further provides an electric drive system control method, which is applied to the electric drive system as described above, and includes:

[0080] Step S100, when it is detected that the electric drive system cannot enter the active short-circuit mode, controlling the electric drive system to enter the coasting mode;

[0081] Specifically, generally, when the electric drive system fails under high-speed operation, it will enter the active short-circuit mode through the control signal. There are two types of active short-circuit modes: one is the upper bridge arm ASC, that is, the upper bridge arm switch of each bridge arm in the inverter is controlled to be in the on state and the lower bridge arm switch of each bridge arm is in the off state; the other is the lower bridge arm ASC, that is, the lower bridge arm switch of each bridge arm in the inverter is controlled to be in the on state and the upper bridge arm switch of each bridge arm is in the off state.

[0082] In some cases, such as controller failure or communication failure, the switch tubes of the upper and lower bridge arms in the inverter cannot be driven to perform switching operations, and the ASC path cannot be formed. At this time, it will be detected that the electric drive system cannot enter the active short-circuit mode.

[0083] When it is detected that the electric drive system cannot enter the active short-circuit mode, the electric drive system is controlled to enter the free-wheeling mode in the safety mode. In the free-wheeling mode, the switches of the upper and lower bridge arms of all bridge arms are in the disconnected state.

[0084] Step S200, after the electric drive system enters the coasting mode, controlling the electric drive system to be disconnected from the power supply device or controlling the electric drive system to be disconnected from the power supply device according to the operating data of the electric drive system.

[0085] Specifically, when the electric drive system enters the inertial gliding mode during high-speed operation, the back electromotive force generated by the motor may be higher than the voltage provided by the power supply device. At this time, the back electromotive force is rectified and fed back to the power supply device through the freewheeling diode to form a closed loop. The motor reversely charges the battery pack in the power supply device and generates a large braking torque at the motor end, avoiding safety problems of the vehicle due to braking torque not operated by the driver.

[0086] like Figure 7 As shown, after the electric drive system enters the inertial gliding mode, the electric drive system can be directly disconnected from the power supply device to protect the power supply device and avoid safety problems caused by a large braking torque generated by the motor during reverse charging, that is, after the electric drive system enters the inertial gliding mode, the electric drive system is controlled to be disconnected from the power supply device.

[0087] Alternatively, after the electric drive system enters the inertial gliding mode, the electric drive system is controlled to be disconnected from the power supply device according to the operating data of the electric drive system, so as to avoid reverse charging of the power supply device when the back electromotive force generated by the motor is higher than the voltage provided by the power supply device, and the motor generating a large braking torque, causing safety problems.

[0088] In this embodiment, when it is detected that the electric drive system cannot enter the active short-circuit mode, the electric drive system is controlled to enter the inertia gliding mode under the safety mode. After entering the inertia gliding mode, in order to protect the power supply device, the electric drive system is directly controlled to be disconnected from the power supply device, or the power supply device and the electric drive system are controlled to be disconnected according to the operating data of the electric drive system. After the electric drive system is disconnected from the power supply device, the electric drive system will not reverse charge the power supply device, thereby protecting the power supply device, and will not generate a large braking torque, thereby avoiding safety problems caused by the braking torque generated by uncontrolled rectification.

[0089] Optionally, controlling the electric drive system to be disconnected from the power supply device based on the operating data of the electric drive system includes: after the electric drive system enters the inertial gliding mode, acquiring the operating data of the electric drive system and the allowable charging power of the battery pack in the power supply device; when the allowable charging power is less than a preset power threshold and the operating data is greater than a first threshold, controlling the electric drive system to be disconnected from the power supply device.

[0090] Specifically, Figure 8 As shown, after the electric drive system enters the inertial gliding mode, the operating data of the electric drive system and the allowable charging power of the battery pack in the battery device are obtained, and it is determined whether to disconnect the electric drive system from the power supply device based on the operating data and the allowable charging power.

[0091] The battery device includes a battery pack, which is usually composed of multiple battery cells. Each battery cell provides a certain voltage and capacity. Common battery cells include lithium-ion batteries, nickel-metal hydride batteries, etc.

[0092] The allowable charging power of the battery pack refers to the maximum charging power that the battery pack can withstand under the premise of ensuring safe and efficient charging of the battery pack. The preset power threshold is a pre-set power threshold. When the allowable charging power of the battery pack is less than the preset power threshold, it means that the allowable charging power of the battery pack is too small. When the operating data is large, that is, the operating data is greater than the first threshold, the battery pack will be overcharged, thereby causing damage to the battery pack. Therefore, when the allowable charging power is less than the preset power threshold and the operating data is greater than the first threshold, the electric drive system is controlled to be disconnected from the power supply device to avoid overcharging the battery pack in the power supply device, prevent hazards such as thermal runaway and internal short circuit of the battery pack, and achieve the purpose of protecting the battery pack.

[0093] When the allowed charging power is large, that is, when the allowed charging power is greater than or equal to the preset power threshold, the motor can charge the battery pack in reverse without causing damage to the battery pack.

[0094] Optionally, the electric drive system is controlled to be disconnected from the power supply device according to the operating data of the electric drive system, including: after the electric drive system enters the inertial gliding mode, obtaining the operating data of the electric drive system; when the operating data is greater than a first threshold, controlling the electric drive system to be disconnected from the power supply device.

[0095] Specifically, Fig. 9 As shown, after the electric drive system enters the coasting mode, only the operation data of the electric drive system is obtained, and it is determined whether to disconnect the electric drive system from the power supply device according to the operation data. In this embodiment, the motor is not allowed to reversely charge the battery pack, that is, when the operation data is greater than the first threshold, the connection between the electric drive system and the power supply device is disconnected to prevent reverse charging, thereby protecting the battery pack.

[0096] Alternatively, if Fig.10 As shown, when the active short-circuit mode of the electric drive system cannot be entered and the vehicle is hit, the electric drive system is controlled to enter the coasting mode and the electric drive system is directly disconnected from the power supply device to achieve the protection purpose.

[0097] Optionally, the power supply device includes a main relay, which is directly connected to the battery pack in the power supply device and connected to the electric drive system through a bus positive wiring harness and a bus negative wiring harness; controlling the electric drive system to disconnect from the power supply device includes: controlling the main relay to disconnect; or, the electric drive system includes a bus switch, which is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness; controlling the electric drive system to disconnect from the power supply device includes: controlling the bus switch to disconnect.

[0098] Specifically, there are two ways to disconnect the electric drive system and the power supply device: one is to disconnect the main relay (corresponding to Figure 2The first relay and the second relay of the main relay are used to realize the disconnection of the electric drive system and the power supply device; wherein, the main relay is directly connected to the battery pack in the power supply device means that the main relay is directly connected to the busbar of the battery pack, and the busbar of the battery pack is a conductive element connecting each battery cell in the battery pack, connecting the current between the battery cells in the battery pack to realize current concentration and distribution, and the main relay is connected to the electric drive system and other high-voltage loads through the bus positive wiring harness and the bus negative wiring harness, and the main relay controls the connection and disconnection of the power supply device with the electric drive system and other high-voltage loads.

[0099] The other is that when a bus switch is provided, the electric drive system and the power supply device are disconnected by disconnecting the bus switch. The bus switch is provided on the positive wiring harness of the bus. The bus switch is located between the positive electrode of the power supply device and the first connection point (the connection point between the protection device and the positive wiring harness of the bus). The specific position can be referred to Figures 3 to 5 The switch position is shown.

[0100] When the electric drive system and the power supply device are disconnected by disconnecting the main relay, the power supply is stopped for all high-voltage devices powered by the power supply device, and the back electromotive force of the electric drive system will cause impact on other high-voltage devices. When the electric drive system and the power supply device are disconnected by disconnecting the bus switch, not only the connection between the electric drive system and the power supply device is disconnected, but also the electric drive system and other high-voltage devices powered by the power supply device are disconnected, which will not cause current impact on other high-voltage devices, thus achieving the purpose of protecting other high-voltage devices.

[0101] Optionally, before controlling the electric drive system to enter the coasting mode, the operating data with the maximum limit is a second threshold, wherein the first threshold and the second threshold may be the same or different.

[0102] Among them, the operating data can be the vehicle speed; when the vehicle includes multiple electric drive systems, that is, multiple motors, the operating data can also be the motor speed and the electric drive back electromotive force. The motor here refers to the motor in the electric drive system other than the one that has the above-mentioned fault.

[0103] The first threshold can be determined by the lowest withstand voltage value of each power device of the high-voltage system and the back electromotive force characteristics of the electric drive system to prevent high voltage hazards; it can also be determined by the high-voltage battery voltage and the uncontrolled rectifier torque characteristics of the electric drive system to prevent unexpected torque. The first threshold can also be determined as the smaller value of the thresholds determined by the above two methods.

[0104] Optionally, the power supply device also includes a pre-charging relay, and the main relay includes a first main relay and / or a second main relay, two ends of the first main relay are respectively connected to the positive electrode of the battery pack and the positive electrode harness of the bus, two ends of the second main relay are respectively connected to the negative electrode of the battery pack and the negative electrode harness of the bus, and the pre-charging relay is connected in parallel with the first main relay; controlling the main relay to disconnect includes: controlling the pre-charging relay to close; controlling the first main relay and / or the second main relay to disconnect.

[0105] Specifically, Fig.11 As shown, the main relay includes a first main relay and a second main relay, one end of the first main relay is connected to the positive electrode of the battery pack, and the other end of the first main relay is connected to the bus positive electrode harness, that is, the other end of the first main relay is connected to the positive electrode of the electric drive system and the positive electrode of other high-voltage loads, one end of the second main relay is connected to the positive electrode of the battery pack, and the other end of the second main relay is connected to the bus negative electrode harness, that is, the other end of the second main relay is connected to the negative electrode of the electric drive system and the negative electrode of other high-voltage loads;

[0106] A pre-charge relay is connected in parallel to the first main relay in the main relays. The first main relay is connected to the positive electrode of the battery pack. The pre-charge relay is also connected to the positive electrode of the battery pack. The second main relay is connected to the negative electrode of the battery pack.

[0107] Among them, the main relay controls the power connection between the battery pack and the electric drive system. When the main relay is closed, the battery pack is allowed to charge the motor, thereby driving the vehicle. The main function of the pre-charge relay is to pre-charge the capacitor of the motor or inverter before the main relay is closed. This can prevent excessive current shock at the moment the main relay is closed, thereby protecting the circuit and equipment.

[0108] Before disconnecting the main relay, closing the pre-charge relay first can ensure the relative stability of the bus voltage, thereby ensuring low-power operation of other high-voltage devices. At the same time, because the pre-charge relay is connected in series with a resistor, it can prevent the battery pack from outputting large currents and also prevent the battery pack from being charged with large currents.

[0109] Optionally, the pre-charge relay is disconnected when the protection device is broken down.

[0110] like Fig.12 As shown, an electric drive system control device 1200 provided in an embodiment of the present invention includes:

[0111] A first control unit 1210 is used to control the electric drive system to enter a coasting mode when it is detected that the electric drive system cannot enter an active short-circuit mode;

[0112] The second control unit 1220 is used to control the electric drive system to be disconnected from the power supply device after the electric drive system enters the coasting mode, or to control the electric drive system to be disconnected from the power supply device according to the operating data of the electric drive system.

[0113] The electric drive system control device of this embodiment is used to implement the electric drive system control method as described above. Its advantages over the prior art are the same as the advantages of the electric drive system control method as described above over the prior art, and will not be repeated here.

[0114] Optionally, the second control unit is also used to control the electric drive system to be disconnected from the power supply device according to the operating data of the electric drive system in the following manner: after the electric drive system enters the inertial gliding mode, the operating data of the electric drive system and the allowable charging power of the battery pack in the power supply device are obtained; when the allowable charging power is less than a preset power threshold and the operating data is greater than a first threshold, the electric drive system is controlled to be disconnected from the power supply device.

[0115] Optionally, the second control unit is further used to control the electric drive system to be disconnected from the power supply device according to the operating data of the electric drive system in the following manner: after the electric drive system enters the inertial gliding mode, the operating data of the electric drive system is obtained; when the operating data is greater than a first threshold value, the electric drive system is controlled to be disconnected from the power supply device.

[0116] Optionally, the power supply device includes a main relay, which is directly connected to the battery pack in the power supply device and connected to the electric drive system through a bus positive wiring harness and a bus negative wiring harness; the above-mentioned second control unit is also used to control the electric drive system to be disconnected from the power supply device in the following manner: controlling the main relay to be disconnected.

[0117] Optionally, the electric drive system includes a bus switch, which is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness; the above-mentioned second control unit is also used to control the electric drive system to be disconnected from the power supply device in the following manner: controlling the bus switch to be disconnected.

[0118] Optionally, the power supply device also includes a pre-charging relay, and the main relay includes a first main relay and / or a second main relay, the two ends of the first main relay are respectively connected to the positive electrode of the battery pack and the bus positive electrode harness, the two ends of the second main relay are respectively connected to the negative electrode of the battery pack and the bus negative electrode harness, and the pre-charging relay is connected in parallel with the first main relay; the above-mentioned second control unit is also used to control the main relay to disconnect in the following ways: controlling the pre-charging relay to close; controlling the first main relay and / or the second main relay to disconnect.

[0119] As shown in the figure, an embodiment of the present invention provides an electric drive system controller, including a memory 1310 and a processor 1320; the memory 1310 is used to store a computer program; the processor 1320 is used to implement the electric drive system control method as described above when executing the computer program.

[0120] In other words, an electric drive system controller is provided, comprising a memory 1310 and a processor 1320 coupled to the memory 1310; the memory 1310 is configured to store a computer program; and the processor 1320 is configured to perform the following operations when executing the computer program:

[0121] When it is detected that the electric drive system cannot enter the active short-circuit mode, controlling the electric drive system to enter the coasting mode;

[0122] After the electric drive system enters the coasting mode, the electric drive system is controlled to be disconnected from the power supply device or the electric drive system is controlled to be disconnected from the power supply device according to the operation data of the electric drive system.

[0123] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the electric drive system control method as described above is implemented.

[0124] In other words, a non-volatile computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following operations:

[0125] When it is detected that the electric drive system cannot enter the active short-circuit mode, controlling the electric drive system to enter the coasting mode;

[0126] After the electric drive system enters the coasting mode, the electric drive system is controlled to be disconnected from the power supply device or the electric drive system is controlled to be disconnected from the power supply device according to the operation data of the electric drive system.

[0127] The technical solution of the embodiment of the present invention, in essence or in other words, the part that contributes to the prior art, or the whole or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for making a computer device (which can be a personal computer, server, or network device, etc.) or a processor perform all or part of the steps of the method of the embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0128] The computer-readable storage medium of this embodiment can be used to implement the above-mentioned electric drive system control method. Its advantages over the prior art are the same as the advantages of the above-mentioned electric drive system control method over the prior art, and will not be repeated here.

[0129] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

[0130] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. An electric drive system, connected to a power supply device through a bus positive wire harness and a bus negative wire harness, characterized in that: The electric drive system includes: an inverter, a capacitor, a protection device and a motor; The protection device is connected between the bus positive wiring harness and the bus negative wiring harness, the capacitor is connected in parallel with the protection device, the first end of the inverter is connected to the bus positive wiring harness, the second end of the inverter is connected to the bus negative wiring harness, and the third end of the inverter is connected to the input end of the motor; Among them, the first withstand voltage threshold of the protection device is greater than the maximum back electromotive force of the motor or the normal operating voltage of the power supply device, and the first withstand voltage threshold is less than the withstand voltage value of all high-voltage devices in the electric drive system.

2. The electric drive system according to claim 1, characterized in that: The electric drive system further includes a bus switch, wherein the bus switch is arranged on the bus positive wire harness, and the bus switch is located between the positive electrode of the power supply device and a first connection point, and the first connection point is a connection point between the protection device and the bus positive wire harness; Alternatively, the bus switch is arranged on the bus negative electrode harness, and the bus switch is located between the negative electrode of the power supply device and a second connection point, and the second connection point is a connection point between the protection device and the bus negative electrode harness.

3. The electric drive system according to claim 1, characterized in that: The electric drive system also includes a fuse, wherein the fuse is connected in series with the protection device, and when the positive electrode of the power supply device, the bus positive wiring harness, the protection device, the fuse, the bus negative wiring harness and the negative electrode of the power supply device form a short circuit, the fuse blows within a preset time period.

4. A method for controlling an electric drive system, characterized in that: Applied to the electric drive system according to any one of claims 1 to 3, the electric drive system control method comprises: When it is detected that the electric drive system cannot enter the active short-circuit mode, controlling the electric drive system to enter the coasting mode; After the electric drive system enters the coasting mode, the electric drive system is controlled to be disconnected from the power supply device or the electric drive system is controlled to be disconnected from the power supply device according to the operation data of the electric drive system.

5. The electric drive system control method according to claim 4, characterized in that: The controlling the electric drive system to be disconnected from the power supply device according to the operation data of the electric drive system comprises: After the electric drive system enters the coasting mode, acquiring operation data of the electric drive system; When the operating data is greater than a first threshold, the electric drive system is controlled to be disconnected from the power supply device.

6. The electric drive system control method according to claim 4, characterized in that: The controlling the electric drive system to be disconnected from the power supply device according to the operation data of the electric drive system comprises: After the electric drive system enters the coasting mode, obtaining operation data of the electric drive system and an allowable charging power of a battery pack in the power supply device; When the allowed charging power is less than a preset power threshold and the operating data is greater than a first threshold, the electric drive system is controlled to be disconnected from the power supply device.

7. The electric drive system control method according to any one of claims 4 to 6, characterized in that: The power supply device includes a main relay, the main relay is directly connected to the battery pack in the power supply device, and is connected to the electric drive system through a bus positive wire harness and a bus negative wire harness; the control of disconnecting the electric drive system from the power supply device includes: controlling the main relay to disconnect; Alternatively, the electric drive system includes a bus switch, which is arranged on the bus positive wiring harness, and the bus switch is located between the positive pole of the power supply device and a first connection point, and the first connection point is the connection point between the protection device and the bus positive wiring harness; controlling the electric drive system to disconnect from the power supply device includes: controlling the bus switch to disconnect.

8. The electric drive system control method according to claim 7, characterized in that: The power supply device further includes a pre-charge relay, the main relay includes a first main relay and / or a second main relay, two ends of the first main relay are respectively connected to the positive electrode of the battery pack and the positive electrode harness of the busbar, two ends of the second main relay are respectively connected to the negative electrode of the battery pack and the negative electrode harness of the busbar, and the pre-charge relay is connected in parallel with the first main relay; The controlling the main relay to be disconnected comprises: Controlling the pre-charging relay to close; The first main relay and / or the second main relay are controlled to be opened.

9. An electric drive system control device, characterized in that: Applicable to the electric drive system according to any one of claims 1 to 3, comprising: A first control unit, configured to control the electric drive system to enter a coasting mode when detecting that the electric drive system cannot enter an active short-circuit mode; The second control unit is used to control the electric drive system to be disconnected from the power supply device after the electric drive system enters the coasting mode, or to control the electric drive system to be disconnected from the power supply device according to the operating data of the electric drive system.

10. An electric drive system controller, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is used to implement the electric drive system control method according to any one of claims 4 to 8 when executing the computer program.

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