A method, controller and system for active discharging of a new energy vehicle

Abstract

The application belongs to the field of new energy vehicles, and provides a new energy vehicle active discharge method, a controller and a system. The new energy vehicle active discharge method comprises the following steps: acquiring a bus voltage, driving a motor controller working mode, a high-voltage relay working state, a high-voltage relay control instruction, a vehicle controller hard-wire enabling state, a charging state, a motor speed, an electric drive system fault condition and a last continuous discharge time in one power-on cycle; judging whether all the set conditions are met at the same time, and if yes, entering an active discharge working condition; the application fully considers the discharge conditions under different working conditions, avoids the occurrence of the working condition of closing the high-voltage relay with current, and avoids relay sticking.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicles, and in particular relates to a method, controller and system for active discharge of new energy vehicles. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] According to relevant regulations, drive motor controllers should have an active discharge function. When the drive motor controller is powered off and switched to a dedicated discharge circuit, it should be able to quickly discharge the charge in the controller's supporting capacitor. In existing active discharge solutions for drive motor controllers, the state of the high-voltage relay is typically used to determine whether to enter active discharge mode. When the high-voltage relay is disconnected, the active discharge mode is entered. This presents some problems. For example, during a rapid power-on process after power-off, if the conditions for active discharge are met after power-off, the motor controller may enter active discharge control and power on before the bus voltage has fully discharged. This could lead to the high-voltage relay closing under a large discharge current, causing relay sticking and other malfunctions. Summary of the Invention

[0004] To address the technical problems mentioned above, this invention provides a method, controller, and system for active discharge of new energy vehicles. This system fully considers discharge conditions under different operating conditions, avoids the occurrence of current-carrying closed high-voltage relays, and prevents relay sticking.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of the present invention provides a method for active discharge of a new energy vehicle.

[0007] A method for active discharge of a new energy vehicle, comprising:

[0008] The system acquires bus voltage, drive motor controller operating mode, high voltage relay operating status, high voltage relay control commands, vehicle controller hard-wired enable status, charging status, motor speed, electric drive system fault status, and the last continuous discharge time within a power-on cycle.

[0009] Determine if all of the following conditions are met simultaneously; if so, proceed to active discharge mode.

[0010] Condition 1 is that the bus voltage is higher than a set voltage threshold; Condition 2 is that the drive motor controller is in a dischargeable mode; Condition 3 is that the high-voltage relay is in an open state; Condition 4 is that a high-voltage relay control instruction sent by the vehicle controller is to disconnect; Condition 5 is that the vehicle controller is hard-wired enabled; Condition 6 is that a charging state sent by the battery management system is not charging; Condition 7 is that the motor speed is less than a set speed threshold; Condition 8 is that the electric drive system does not have a fault affecting the active discharge function; and Condition 9 is that the last continuous discharge time in a power-on cycle is less than a set continuous discharge time threshold.

[0011] As an embodiment, when any one of Conditions 1 to 9 is not met after entering the active discharge working condition, the active discharge working condition is directly exited.

[0012] As an embodiment, the discharge mode includes a post-operation discharge mode and an emergency discharge mode.

[0013] As an embodiment, the determination process that the high-voltage relay is in the open state is:

[0014] If the positive main relay and the pre-charge relay on the positive electrode are both open, or the negative main relay on the negative electrode is open, it is considered that the high-voltage relay is in the open state; wherein the high-voltage relay includes the positive main relay and the pre-charge relay connected to the positive electrode of the high-voltage battery, and the negative main relay connected to the negative electrode of the high-voltage battery.

[0015] As an embodiment, the fault affecting the active discharge function includes over-temperature of the drive motor, over-temperature of the drive motor controller, and over-current.

[0016] A second aspect of the present application provides a vehicle controller.

[0017] A vehicle controller, comprising:

[0018] An information acquisition module for acquiring a bus voltage, a drive motor controller working mode, a high-voltage relay working state, a high-voltage relay control instruction, a vehicle controller hard-wire enabled state, a charging state, a motor speed, an electric drive system fault condition, and a last continuous discharge time in a power-on cycle;

[0019] An active discharge determination module for determining whether all of the following conditions are met at the same time, and if so, entering an active discharge working condition;

[0020] Wherein, condition 1 is that the bus voltage is higher than a set voltage threshold; condition 2 is that the drive motor controller is in a dischargeable mode; condition 3 is that the high-voltage relay is in an open state; condition 4 is that a high-voltage relay control instruction sent by the vehicle controller is disconnection; condition 5 is that the vehicle controller is hard-wired enabled; condition 6 is that a charging state sent by the battery management system is uncharged; condition 7 is that the motor speed is less than a set speed threshold; condition 8 is that the electric drive system does not have a fault affecting the active discharge function; and condition 9 is that the last continuous discharge time in a power-on cycle is less than a set continuous discharge time threshold.

[0021] As an implementation form, in the active discharge determination module, when any one of conditions 1-9 is not met after entering the active discharge working condition, the active discharge working condition is directly exited.

[0022] As an implementation form, in the active discharge determination module, the discharge mode includes a post-operation discharge mode and an emergency discharge mode.

[0023] As an implementation form, in the active discharge determination module, the determination process that the high-voltage relay is in the open state is:

[0024] If the main positive relay and the pre-charge relay on the positive electrode are both open, or the main negative relay on the negative electrode is open, it is considered that the high-voltage relay is in the open state; wherein the high-voltage relay includes the main positive relay and the pre-charge relay connected to the positive electrode of the high-voltage battery, and the main negative relay connected to the negative electrode of the high-voltage battery.

[0025] As an implementation form, in the active discharge determination module, the fault affecting the active discharge function includes drive motor over-temperature, drive motor controller over-temperature, and over-current.

[0026] The third aspect of the application provides a new energy vehicle active discharge system.

[0027] A new energy vehicle active discharge system includes a drive motor controller, a drive motor, a battery management system, a high-voltage relay, and a vehicle controller as described above.

[0028] The battery management system, the vehicle controller, and the drive motor controller perform information interaction through a CAN bus; the high-voltage relay is controlled by the battery management system, the battery management system is used to control the high-voltage relay and feed back the state of the high-voltage relay to the CAN bus; and the drive motor controller is used to control the drive motor and feed back the running information of the drive motor to the CAN bus.

[0029] Compared with the prior art, the new energy vehicle active discharge system has the following beneficial effects:

[0030] The application considers different working conditions, uses bus voltage, drive motor controller working mode, high voltage relay working state, high voltage relay control instruction, whole vehicle controller hard line enable state, charging state, motor rotating speed, electric drive system fault condition and last continuous discharge time in a power-on cycle to form discharge condition, avoids occurrence of high voltage relay working condition with current closing and relay sticking condition, and improves stability of new energy vehicle device operation.

[0031] Advantages of the additional aspects of the application will be partly given in the following description, partly will become apparent from the following description, or will be understood by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein by reference. The illustrations are shown schematically and are not intended to limit the application in any way.

[0033] Figure 1 is a system structure diagram of a new energy vehicle active discharge according to an embodiment of the application;

[0034] Figure 2 is a new energy vehicle active discharge flowchart according to an embodiment of the application;

[0035] Figure 3 is a new energy vehicle active discharge flowchart according to an embodiment of the application. DETAILED DESCRIPTION

[0036] The application will be further described below with reference to the drawings and embodiments.

[0037] It should be noted that the following detailed description is illustrative only and is not intended to limit the application in any way. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0038] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0039] In one or more embodiments, referring to Figure 2 , a new energy vehicle active discharge method is provided, which includes the following steps:

[0040] Step a: obtaining bus voltage, driving motor controller working mode, high voltage relay working state, high voltage relay control instruction, vehicle controller hardwire enable state, charging state, motor speed, electric drive system fault condition and last continuous discharge time in a power-on cycle;

[0041] Step b: determining whether all the following conditions are met simultaneously, if yes, entering active discharge working condition;

[0042] Condition 1 is that the bus voltage is higher than the set voltage threshold (for example, the set threshold is 60V).

[0043] Condition 2 is that the driving motor controller is in a dischargeable mode; wherein the dischargeable mode includes a post-operation discharge mode and an emergency discharge mode.

[0044] Condition 3 is that the high voltage relay is in an open state.

[0045] Condition 4 is that the high voltage relay control instruction sent by the vehicle controller is to disconnect.

[0046] Wherein, the determination process of the high voltage relay in the open state is:

[0047] If the positive main relay and the pre-charge relay above the positive electrode are both disconnected, or the negative main relay above the negative electrode is disconnected, it is considered that the high voltage relay is in an open state; wherein the high voltage relay includes the main positive relay and the pre-charge relay connected to the positive electrode of the high voltage battery, and the main negative relay connected to the negative electrode of the high voltage battery.

[0048] Condition 5 is that the vehicle controller hardwire is enabled.

[0049] For example: the enable state is set to 12V high level given by the vehicle controller to the motor drive controller.

[0050] Condition 6 is that the charging state sent by the battery management system is not charging.

[0051] Wherein, the advantage of condition 6 is that in some electronic architectures, if the battery is in a charging state, the discharge loop bus also has high voltage, so in this case, active discharge cannot be entered.

[0052] Condition 7 is that the motor speed is less than the set speed threshold (for example, the speed threshold is 800 rpm, the size of the speed threshold can be set according to the actual situation by those skilled in the art).

[0053] Condition 8 is that the electric drive system does not have a fault affecting the active discharge function.

[0054] Wherein, the fault affecting the active discharge function includes but is not limited to driving motor over-temperature, driving motor controller over-temperature and over-current.

[0055] The benefit of condition 8 is that when there is some fault in the electric drive system that affects the active discharge function, such as an over-temperature fault of the electric drive system, active discharge at this time will further cause the temperature to rise, thereby damaging the electric drive system; such as a fault of a power device of a certain phase and bridge arm, active discharge at this time will cause the power device to be unable to conduct according to the intended sequence, thereby damaging the power device, and the like.

[0056] Condition 9 is that the last continuous discharge time in one power-on cycle is less than a set continuous discharge time threshold (wherein the size of the threshold can be specifically set by a person skilled in the art according to actual conditions). The benefit of condition 9 is to avoid repeated entry into the active discharge function after discharge timeout to damage the motor controller.

[0057] According to Figure 3 When any one of conditions 1 to 9 is not met after entering the active discharge working condition, the active discharge working condition is directly exited.

[0058] This embodiment considers different working conditions, uses bus voltage, drive motor controller working mode, high-voltage relay working state, high-voltage relay control instruction, vehicle controller hard-wire enable state, charging state, motor speed, electric drive system fault condition, and the last continuous discharge time in one power-on cycle to form discharge conditions, avoids the occurrence of the high-voltage relay working condition with current closed and the relay sticking condition, and improves the stability of the operation of new energy vehicle devices.

[0059] In one or more embodiments, a vehicle controller is also provided, comprising:

[0060] (1) an information acquisition module for acquiring bus voltage, drive motor controller working mode, high-voltage relay working state, high-voltage relay control instruction, vehicle controller hard-wire enable state, charging state, motor speed, electric drive system fault condition, and the last continuous discharge time in one power-on cycle;

[0061] (2) an active discharge determination module for determining whether all of the following conditions are met at the same time, and if so, entering an active discharge working condition;

[0062] Wherein, condition 1 is that the bus voltage is higher than a set voltage threshold; condition 2 is that the drive motor controller is in a dischargeable mode; condition 3 is that the high-voltage relay is in a disconnected state; condition 4 is that the high-voltage relay control instruction sent by the vehicle controller is to disconnect; condition 5 is that the vehicle controller hard-wire is enabled; condition 6 is that the charging state sent by the battery management system is not charging; condition 7 is that the motor speed is less than a set speed threshold; condition 8 is that the electric drive system does not have a fault that affects the active discharge function; and condition 9 is that the last continuous discharge time in one power-on cycle is less than a set continuous discharge time threshold.

[0063] In the specific implementation process, in the active discharge determination module, when any one of conditions 1-9 is not met after entering the active discharge working condition, the active discharge working condition is directly exited.

[0064] In some other embodiments, in the active discharge determination module, the discharge mode includes a post-operation discharge mode and an emergency discharge mode.

[0065] In some other embodiments, in the active discharge determination module, the determination process that the high-voltage relay is in an open state is as follows:

[0066] If the positive main relay and the pre-charge relay on the positive pole are both open, or the negative main relay on the negative pole is open, it is considered that the high-voltage relay is in an open state; wherein the high-voltage relay includes the positive main relay and the pre-charge relay connected to the positive pole of the high-voltage battery, and the negative main relay connected to the negative pole of the high-voltage battery.

[0067] In some embodiments, in the active discharge determination module, the faults affecting the active discharge function include over-temperature of the drive motor, over-temperature of the drive motor controller, and over-current.

[0068] Here, each module in the vehicle controller described above corresponds to each step in the method of active discharge of the new energy vehicle described above, and the specific implementation process is the same, which will not be repeated here.

[0069] According to Figure 1 In one or more embodiments, a new energy vehicle active discharge system is also provided, which includes a drive motor controller (MCU), a drive motor, a battery management system (BMS), a high-voltage relay, and a vehicle controller as described above;

[0070] The battery management system, the vehicle controller, and the drive motor controller exchange information through the CAN bus; the high-voltage relay is controlled by the battery management system, which is used to control the high-voltage relay and feed back the state of the high-voltage relay to the CAN bus; the drive motor controller is used to control the drive motor and feed back the operation information of the drive motor to the CAN bus.

[0071] Figure 1 The working process of the new energy vehicle active discharge system includes the steps of determining that the new energy vehicle enters the active discharge and determining that the new energy vehicle exits the active discharge.

[0072] The specific steps of determining that the new energy vehicle enters the active discharge are as follows:

[0073] Step 1.1: MCU judges whether the bus voltage collected by itself is higher than the set threshold value, which is 60V. If yes, go to step 1.2; if no, go to step 1.11;

[0074] Step 1.2: whether the MCU mode is in the dischargeable mode, which includes Afterrun and Emergency Discharge. If yes, go to step 1.3; if no, go to step 1.11;

[0075] Step 1.3: whether the high-voltage relay state sent by BMS is in the off state. The high-voltage relay includes the main positive relay and the pre-charge relay connected to the positive pole of the high-voltage battery, and the main negative relay connected to the negative pole of the high-voltage battery. If both the main positive relay and the pre-charge relay connected to the positive pole are off, or the main negative relay connected to the negative pole is off, it is considered that the high-voltage relay is in the off state. If yes, go to step 1.4; if no, go to step 1.11;

[0076] Step 1.4: whether the high-voltage relay control instruction sent by VCU is off. If yes, go to step 1.5; if no, go to step 1.11;

[0077] Step 1.5: whether the hard-wire enable signal from VCU to MCU is enabled, which is in the 12V high level. If yes, go to step 1.6; if no, go to step 1.11;

[0078] Step 1.6: whether the battery charging state sent by BMS is uncharged. If yes, go to step 1.7; if no, go to step 1.11;

[0079] Step 1.7: whether the motor rotation speed collected by MCU is less than the set threshold value, which is 800rpm. If yes, go to step 1.8; if no, go to step 1.11;

[0080] Step 1.8: whether the electric drive system diagnosed by MCU has no active discharge-affecting faults. The electric drive system includes MCU and drive motor. The active discharge-affecting faults refer to motor over-temperature, MCU over-temperature, over-current, module fault, etc. If yes, go to step 1.9; if no, go to step 1.11;

[0081] Step 1.9: MCU judges whether the last continuous discharge time in a power-on cycle is less than the set threshold value. The set threshold value is 5s. If there is no active discharge in this power-on cycle, it is considered that the last continuous discharge time is 0. If yes, go to step 1.10; if no, go to step 1.11;

[0082] Step 1.10: MCU executes active discharge;

[0083] Step 1.11: Feedback discharge status and result.

[0084] The specific steps for the new energy vehicle to exit the active discharge are as follows:

[0085] Step 2.1: MCU judges whether the bus voltage collected by it is lower than the set threshold value, which is 36V. Unlike the previous threshold value of 60V, it is to set a hysteresis interval to prevent the rebound of the bus voltage when exiting the active discharge working condition. If not, go to step 2.2; if yes, go to step 2.11;

[0086] Step 2.2: MCU mode is not in dischargeable mode, if not, go to step 2.3; if yes, go to step 2.11;

[0087] Step 2.3: The high-voltage relay state sent by the BMS is in the connected state. If the positive main positive relay or pre-charge relay above the positive electrode is connected, and the negative main negative relay above the negative electrode is connected, it is considered that the high-voltage relay is in the connected state. If not, go to step 2.4; if yes, go to step 2.11;

[0088] Step 2.4: The high-voltage relay control instruction sent by the VCU is connected, if not, go to step 2.5; if yes, go to step 11;

[0089] Step 2.5: The hard-wire enable signal of the VCU to the MCU is not enabled, which is low. If not, go to step 2.6; if yes, go to step 2.11;

[0090] Step 2.6: The battery charging state sent by the BMS is charging, if not, go to step 7; if yes, go to step 2.11;

[0091] Step 2.7: The motor speed collected by the MCU is greater than the set threshold value, which is 800rpm. If not, go to step 2.8; if yes, go to step 2.2.11;

[0092] Step 2.8: The MCU diagnoses whether the electric drive system has a fault that affects active discharge. If not, go to step 2.9; if yes, go to step 11;

[0093] Step 2.9: The MCU judges whether the current discharge time is greater than the set threshold value. The set threshold value is 5s. If not, go to step 2.10; if yes, go to step 2.11;

[0094] Step 2.10: The MCU maintains the current active discharge state;

[0095] Step 2.11: MCU exits the active discharge state.

[0096] In this embodiment, since the high-voltage relay control instruction sent by the VCU precedes the high-voltage relay state feedback sent by the BMS, invalid discharge during power-up is avoided.

[0097] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for active discharging of a new energy vehicle, characterized in that, The method comprises: acquiring bus voltage, drive motor controller working mode, high-voltage relay working state, high-voltage relay control instruction, vehicle controller hard-wire enabling state, charging state, motor speed, electric drive system fault condition and last continuous discharge time in a power-on cycle; determining whether all of the following conditions are met simultaneously, and if so, entering an active discharge working condition; condition 1 is that the bus voltage is higher than a set voltage threshold; condition 2 is that the drive motor controller is in a dischargeable mode; condition 3 is that the high-voltage relay is in an open state; condition 4 is that the high-voltage relay control instruction sent by the vehicle controller is to disconnect; condition 5 is that the vehicle controller hard-wire is enabled; condition 6 is that the charging state sent by the battery management system is uncharged; condition 7 is that the motor speed is less than a set speed threshold; condition 8 is that the electric drive system does not have a fault affecting the active discharge function; and condition 9 is that the last continuous discharge time in a power-on cycle is less than a set continuous discharge time threshold.

2. The method for active discharging of a new energy vehicle according to claim 1, characterized in that, After entering the active discharge working condition, when any one of conditions 1 to 9 is not met, the active discharge working condition is directly exited.

3. The method of claim 1 or 2, wherein, The discharge mode comprises a post-operation discharge mode and an emergency discharge mode.

4. The method for active discharging of a new energy vehicle according to claim 1 or 2, characterized in that, The determination process that the high-voltage relay is in the open state is: if the positive main relay and the pre-charge relay on the positive electrode are both open, or the negative main relay on the negative electrode is open, it is considered that the high-voltage relay is in the open state; wherein the high-voltage relay comprises the positive main relay and the pre-charge relay connected to the positive electrode of the high-voltage battery, and the negative main relay connected to the negative electrode of the high-voltage battery.

5. The method for active discharging of a new energy vehicle according to claim 1 or 2, characterized in that, The faults affecting the active discharge function include drive motor over-temperature, drive motor controller over-temperature and over-current.

6. A vehicle control unit characterized by comprising: The method comprises: an information acquisition module for acquiring bus voltage, drive motor controller working mode, high-voltage relay working state, high-voltage relay control instruction, vehicle controller hard-wire enabling state, charging state, motor speed, electric drive system fault condition and last continuous discharge time in a power-on cycle; an active discharge determination module for determining whether all of the following conditions are met simultaneously, and if so, entering an active discharge working condition; wherein condition 1 is that the bus voltage is higher than a set voltage threshold; condition 2 is that the drive motor controller is in a dischargeable mode; condition 3 is that the high-voltage relay is in an open state; condition 4 is that the high-voltage relay control instruction sent by the vehicle controller is to disconnect; condition 5 is that the vehicle controller hard-wire is enabled; condition 6 is that the charging state sent by the battery management system is uncharged; condition 7 is that the motor speed is less than a set speed threshold; condition 8 is that the electric drive system does not have a fault affecting the active discharge function; and condition 9 is that the last continuous discharge time in a power-on cycle is less than a set continuous discharge time threshold.

7. The vehicle control unit according to claim 6, characterized in that, In the active discharge determination module, after entering the active discharge working condition, when any one of conditions 1 to 9 is not met, the active discharge working condition is directly exited.

8. The vehicle control unit according to claim 6 or 7, characterized in that, In the active discharge determination module, the discharge mode comprises a post-operation discharge mode and an emergency discharge mode.

9. The vehicle control unit according to claim 6 or 7, characterized in that, In the active discharge determination module, the determination process that the high-voltage relay is in the open state is: If the main positive relay and the pre-charge relay on the positive pole are both disconnected, or the main negative relay on the negative pole is disconnected, the high-voltage relay is considered to be in a disconnected state; wherein the high-voltage relay includes the main positive relay and the pre-charge relay connected to the positive pole of the high-voltage battery, and the main negative relay connected to the negative pole of the high-voltage battery; Or In the active discharge determination module, the faults affecting the active discharge function include over-temperature of the drive motor, over-temperature of the drive motor controller, and over-current.

10. A new energy vehicle active discharge system, characterized in that, The vehicle controller includes a drive motor controller, a drive motor, a battery management system, a high-voltage relay, and any one of claims 6-9. The battery management system, the vehicle controller, and the drive motor controller interact information through a CAN bus; the high-voltage relay is controlled by the battery management system, the battery management system is used to control the high-voltage relay and feed back the state of the high-voltage relay to the CAN bus; the drive motor controller is used to control the drive motor, and feed back the running information of the drive motor to the CAN bus.

Images