A method for controlling motor stall heating of an electric vehicle

Abstract

The application discloses a motor locked-rotor heating control method for an electric vehicle, and comprises the following steps: executing a motor locked-rotor heating mode based on a control protection strategy of a vehicle controller and a motor controller; the control protection strategy comprises the following steps: generating an initial reference current for locked-rotor heating by PI control of the motor controller based on the difference between a target temperature of cooling liquid and a real-time temperature, and generating a final reference current by combining whether the locked-rotor power exceeds the locked-rotor heating power limit value of the vehicle controller and whether a power reduction process is triggered; fixing the current control angle as the angle at the moment when the motor controller enters locked-rotor during the motor locked-rotor heating process; selecting whether to load the current according to the jitter risk when the locked-rotor heating enters a given current; decreasing the current according to a locked-rotor exit current strategy when the locked-rotor heating exits; maintaining the motor locked-rotor heating mode until the current safely exits when the locked-rotor heating function is abnormal. The motor locked-rotor heating function and user experience of the vehicle are ensured.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a method for controlling stall heating in an electric vehicle motor. Background Technology

[0002] In low-temperature environments, the chemical reaction rate of batteries in new energy vehicles slows down, internal resistance increases, and discharge capacity decreases, resulting in reduced battery performance.

[0003] Stall-rotor heating of electric motors has become a common method for auxiliary heating of batteries in new energy vehicles. Stall-rotor heating typically involves supplying an id current to the motor while the vehicle is stationary and in park (P) to generate heat, which indirectly heats the coolant. Utilizing the waste heat generated by the motor and inverter reduces the energy consumption of additional heating equipment and improves the overall energy efficiency of the vehicle.

[0004] During the motor stall heating process, vehicle malfunctions or electric drive system malfunctions may occur. When stall heating is initiated, in progress, or withdrawn, factors such as gear backlash, human-induced shaking of the vehicle, or interference from the resolver signal may cause fluctuations in motor speed and vibration of the vehicle. All of the above situations will affect the motor stall heating function and will also affect the customer's driving experience.

[0005] Therefore, there is an urgent need for a method to control the stall heating of electric vehicle motors, so as to adjust the control and protection strategies of the vehicle and motor controllers during the stall heating process, add fault detection for abnormal stall heating functions, and take timely protective measures when vehicle or electric drive system failures occur. Anti-shake control strategies should be added during the normal stall heating entry, stall process and exit to avoid motor speed fluctuations and vehicle vibration during stall heating, thereby ensuring the normal operation of the stall heating function and the customer's driving experience. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for controlling stalled heating in an electric vehicle motor, comprising the following steps: When the vehicle controller determines that the motor stall heating requirement is met, it sends a motor stall heating request to the motor controller. The motor controller responds to the motor stall heating request and executes the motor stall heating mode based on the control and protection strategy of the vehicle controller and the motor controller, wherein the control and protection strategy includes: a. The motor controller generates an initial reference current for stall heating based on the difference between the target temperature and the real-time temperature of the coolant via PI control. Based on whether the stall power exceeds the vehicle controller's motor stall heating power limit and whether derating is triggered, the final reference current is generated. :

[0007] In the formula, This is the proportionality coefficient; This is the reduction factor; b. During the motor stall heating process, the current control angle is fixed at the angle at which the motor controller enters the stall state; when the stall heating enters the given state... When applying current, select whether to load based on the risk of jitter. Current; when the stalled rotor heating is discontinued, the current decreases in a preset timing sequence according to the stalled rotor discontinuation current strategy. Current, Current; c. Implement a graded response protection strategy for abnormal stall heating function, and maintain the stall heating mode of the motor until the current safely exits.

[0008] Furthermore, the aforementioned , The methods for determining this include: If the stall power of the electric drive system exceeds the stall power limit of the motor sent by the vehicle controller, the initial reference current is proportionally reduced. The range is 0-1.0; otherwise, =1.0; If the electric drive system triggers derating, the initial reference current will be drated. The range is 0-1.0; otherwise, =1.0.

[0009] Furthermore, the step of selecting whether to load based on jitter risk... Current, specifically including: The stalled rotor heating enters the given state When the current is applied, verify whether there is fluctuation in motor speed or vibration of the entire vehicle using a test bench or a complete vehicle: If it exists, then the above is given first. Current, to be described After the current reaches the given target value, the given value is then given. Current, wherein, The current amplitude is less than the Current amplitude; If it does not exist, then only the stated... Electric current.

[0010] Furthermore, the stall heating enters a given... When the current is present, the Current, the The current amplitude settings shall satisfy the following conditions: The The current amplitude is set to meet the power requirements for stall heating of the vehicle's motor; The The current amplitude setting must ensure that there is no fluctuation in motor speed or vibration of the whole vehicle when the motor is stalled.

[0011] Furthermore, the stall-removal current strategy includes: The The current decreases to 0 at a set rate. Or, the stated After the current decreases to 0 at a set rate, the... The current then decreases to 0 at the set rate.

[0012] Furthermore, the aforementioned Current, the The set rate of current decrease must meet the requirements of the vehicle motor stall heating current decrease rate.

[0013] Furthermore, the graded response protection strategy for abnormal stall heating function includes: When the absolute value of the motor speed exceeds the stall heating speed protection threshold at the first set time, a first-level warning fault is triggered; When the actual output power of the motor stall exceeds the rated multiple of the motor stall heating power limit at a second set time, a first-level warning fault is triggered; wherein, the motor stall heating power limit is the minimum value between the motor's own stall power limit and the power limit sent by the vehicle controller.

[0014] Furthermore, during the first-level warning fault response, the stall exit current is decreased according to the stall exit current strategy. Current and the Current is applied, and the stalled rotor heating mode is maintained.

[0015] Furthermore, the stall-heating function malfunction also includes a three-level fault response: When the motor controller detects a lost message from the vehicle controller, a verification failure, or a level 3 fault in the electric drive system, it immediately and proactively exits the stall heating function and maintains the stall heating working mode.

[0016] Furthermore, the method also includes the vehicle controller detecting the vehicle status in real time: When a Level 3 serious fault is detected in a vehicle component, an EPB caliper is loose, or the motor stall heating function is abnormal, immediately stop sending stall heating mode requests and switch the request mode to send a standby mode request. When the vehicle controller normally exits the stall heating function, it immediately stops sending stall heating mode requests, switches to a standby mode request, and the motor controller, upon receiving the standby mode request, will... Current, the The current is set to 0, and after the current returns to zero, the stall heating mode is exited and the standby mode is switched.

[0017] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: This invention generates a final reference current by combining whether the stall power of the electric drive system exceeds the stall heating power limit of the vehicle controller's motor and whether derating is triggered. This enables power adaptive protection; it also achieves this through angle locking and load selection based on jitter risk. The current eliminates mechanical vibration; and the system maintains stability based on a graded fault response mechanism; it fully considers the actual situation of motor stall heating when the vehicle is parked, and adjusts the control and protection strategy of motor stall heating to better ensure the vehicle motor stall heating function and user experience. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is an overall flowchart disclosed in an embodiment of the present invention; Figure 2 This is a schematic diagram of the motor stall heating control process disclosed in an embodiment of the present invention; Figure 3 This is a block diagram of the motor stall heating control current setting strategy disclosed in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention aims to provide a method for controlling the stall heating of an electric vehicle motor. During the stall heating process, the control and protection strategies of the vehicle and motor controllers are adjusted, and fault detection of abnormal stall heating functions is added. When a vehicle fault or electric drive system fault occurs, corresponding protective measures are taken in a timely manner. Anti-shake control strategies are added during the normal stall heating entry, stall process, and exit to avoid motor speed fluctuations and vehicle vibration during stall heating.

[0022] Please see Figure 1-2 The electric vehicle motor stall heating control method disclosed in this invention mainly includes the following steps: S1. When the vehicle controller determines that the motor stall heating requirement is met, it sends a motor stall heating request to the motor controller.

[0023] To further explain, the vehicle controller makes a comprehensive judgment based on factors such as the vehicle's heating requirements, gear position, operating mode, and EPB status. When the vehicle has a stall heating requirement, the current gear is P, the operating mode is standby mode, and the EPB is in a clamped state, it sends a motor stall heating mode request, a coolant target temperature request, and a motor stall power limit to the motor controller via the vehicle's CAN network, which the motor controller receives in real time.

[0024] S2, The motor controller responds to the motor stall heating request.

[0025] To further explain, after receiving a request for a stalled heating mode, the motor controller determines whether the current state meets the heating conditions. These conditions include the mode request, whether the high-voltage positive and negative relays are closed, and whether the motor speed is less than a certain threshold. Once the heating conditions are met, the controller responds to the heating request and enters the stalled heating mode.

[0026] S3. Based on the control and protection strategies of the vehicle controller and motor controller, the motor stall heating mode is executed.

[0027] To further explain, in order to ensure the normal operation and deactivation of the motor stall heating function, the control and protection strategies of the vehicle and motor controllers mainly include the following three aspects: a. The motor controller generates an initial reference current for stall heating based on the difference between the target coolant temperature and the real-time temperature via PI control. Initial reference current The amplitude is limited by the hardware of the electric drive system itself and the stall power. The final reference current is generated by considering whether the stall power of the electric drive system exceeds the stall heating power limit of the vehicle controller motor and whether derating is triggered. :

[0028] In the formula, This is the proportionality coefficient; This is the reduction factor.

[0029] In the further plan, , The methods for determining this include: If the stall power of the electric drive system exceeds the stall power limit of the motor sent by the vehicle controller, the initial reference current will be reduced proportionally. The range is 0-1.0; otherwise, =1.0.

[0030] If the electric drive system triggers derating, the initial reference current will be drated. The range is 0-1.0; otherwise, =1.0.

[0031] To further explain, during the stall heating process, the motor controller performs PI control of the motor stall current based on the difference between the target coolant temperature requested by the vehicle controller and the real-time detected coolant temperature, and outputs the initial reference current for stall heating. Initial reference current The amplitude is limited by the electric drive system's own hardware and stall power. The motor controller simultaneously monitors signals such as bus voltage, current, motor temperature, power module temperature, and coolant temperature in real time, and determines whether the stall power of the electric drive system exceeds the vehicle controller's motor stall power limit and whether derating is triggered. Specifically: If the stall power of the electric drive system exceeds the stall power limit of the motor in the vehicle controller, the motor controller requests a reference current. The scaled-down process is performed, with a scaling factor of [value missing]. , The range is 0~1.0; if the vehicle controller's motor stall power limit is greater than or equal to the electric drive system stall power, the coefficient... The value is 1.0.

[0032] If the electric drive system triggers derating, the motor controller requests the reference current. The amount will be reduced, with a reduction factor of [percentage missing]. , The range is 0~1.0; if the electric drive system does not trigger derating, The value is 1.0. Final reference current for motor stall heating. That is .

[0033] The reference current used for motor stall heating control is not the stall heating reference current output by PI control, which is not directly based on the coolant target temperature requested by the vehicle controller and the real-time detected coolant temperature difference. Instead, it comprehensively considers whether the stall power of the electric drive system exceeds the stall heating power limit of the vehicle controller's motor and whether derating is triggered, and adjusts the reference current accordingly. With treatment coefficient , The multiplication factor is used as the reference current for the stalled rotor heating of the motor. This method ensures that the stalled rotor heating function operates as required and in accordance with the actual system conditions, avoiding functional abnormalities and unnecessary malfunctions.

[0034] b. To avoid motor speed fluctuations and vehicle vibrations caused by factors such as human-induced shaking or resolver signal interference, the current control angle during the motor stall heating process is fixed at the angle at the moment the motor controller enters the stall heating mode. The motor speed is calculated in real-time using the resolver signal.

[0035] Considering factors such as gear backlash: b1. When the motor stall heating starts, the given... Current, select whether to apply based on jitter risk. Electric current.

[0036] Specifically, when the stalled rotor heating enters the given... When the current is applied, verify whether there is motor speed fluctuation or vehicle vibration using a test bench or a complete vehicle. If so, first provide... Current, waiting The current is given after reaching the given target value. Current, where Current amplitude less than Current amplitude. If not specified, only the current amplitude will be given. Electric current.

[0037] To further explain, when mechanical vibration is present, Current, The current is given by first providing a small amplitude at a certain rate. Current is used to counteract the effect of gear backlash, until Once the current reaches the given target value, it is then given at a certain rate. Electric current.

[0038] In a further proposed scheme, the stalled rotor heating enters a given... When current is applied, Current, The current amplitude settings satisfy the following: The current amplitude is set to meet the vehicle motor stall heating power requirements. The current amplitude setting must ensure that there is no motor speed fluctuation or vehicle vibration when the motor enters a stall state. Meanwhile, Current, The given current rate must meet the requirements of the vehicle motor stall heating current loading rate.

[0039] b2. When the motor stall heating is disengaged, considering factors such as gear backlash, the stall exit current should be decreased in a preset sequence according to the stall exit current strategy. Current, Current. Among these, the stall-to-exit current strategy includes: The current decreases to 0 at a set rate.

[0040] or, The current first decreases to 0 at a set rate, and then... The current then decreases to 0 at the set rate.

[0041] In the further plan, Current, The set rate of current decrease must meet the requirements of the vehicle motor stall heating current decrease rate.

[0042] During stall heating, the current control angle is always the angle calculated by the motor controller when entering stall heating mode. The motor speed is calculated in real time via resolver signal. A small value is given when stall heating is entered and exited, taking into account the actual gear backlash of the vehicle's electric drive system. Electric current. Current, The current is given according to the above scheme strategy. This approach can avoid motor speed fluctuations and vehicle vibration caused by factors such as human shaking, resolver signal interference, or gear backlash.

[0043] c. Implement a graded response protection strategy for abnormal stall heating function, and maintain the stall heating mode of the motor until the current is safely withdrawn.

[0044] In this embodiment, the graded response protection strategy for abnormal stall heating function includes: A level one warning fault is triggered when the absolute value of the motor speed exceeds the stall heating speed protection threshold after a first set time. The first set time can be 50ms, and the stall heating speed protection threshold is set to 10 revolutions per minute.

[0045] When the actual output power of the stalled motor exceeds the rated multiple of the stalled heating power limit of the motor by a certain number of times within a second set time, a first-level warning fault is triggered. The stalled heating power limit of the motor is the minimum value between the stalled power limit of the motor itself and the power limit sent by the vehicle controller; the second set time can be 500ms, and the rated multiple can be set to 1.2 times.

[0046] When a Level 1 warning fault is triggered, the stall current is reduced according to the stall exit current strategy. Current and Current is applied, and the stalled rotor heating mode is maintained.

[0047] When the motor controller detects a lost message from the vehicle controller, a verification fault, or a level 3 fault in the electric drive system, it will immediately and proactively exit the stall heating function, handle the situation according to the corresponding fault protection safety strategy, and maintain the stall heating working mode.

[0048] The vehicle controller monitors the vehicle's status in real time. When it detects a Level 3 severe fault in a vehicle component, EPB caliper loosening, or abnormal motor stall heating function, it immediately stops sending stall heating mode requests and switches to a standby mode request. Similarly, when the vehicle controller normally exits the stall heating function, it also immediately stops sending stall heating mode requests, switches to a standby mode request, and the motor controller, upon receiving the standby mode request, will... Current, The current is set to 0, and after the current returns to zero, the stall heating mode is exited and the standby mode is switched.

[0049] It should be noted that, as mentioned earlier, disabling the stall heating function means immediately stopping the current output, i.e. Current, When the current returns to zero, the stall heating behavior terminates. Maintaining the stall heating mode means that the system state machine keeps the stall heating mode flag active and does not switch to other modes, such as standby mode or driving mode.

[0050] In summary, compared with the prior art, the present invention fully considers the actual situation of motor stall heating when the vehicle is parked, and adjusts the control and protection strategy of motor stall heating, so as to better ensure the vehicle motor stall heating function and user experience.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling stall heating in an electric vehicle motor, characterized in that, Includes the following steps: When the vehicle controller determines that the motor stall heating requirement is met, it sends a motor stall heating request to the motor controller. The motor controller responds to the motor stall heating request and executes the motor stall heating mode based on the control and protection strategy of the vehicle controller and the motor controller, wherein the control and protection strategy includes: a. The motor controller generates an initial reference current for stall heating based on the difference between the target temperature and the real-time temperature of the coolant via PI control. Based on whether the stall power of the electric drive system exceeds the stall heating power limit of the vehicle controller motor and whether derating is triggered, the final reference current is generated. : In the formula, This is the proportionality coefficient; This is the reduction factor; b. During the motor stall heating process, the current control angle is fixed at the angle at which the motor controller enters the stall state; when the stall heating enters the given state... When applying current, select whether to load based on the risk of jitter. Current; when the stalled rotor heating is discontinued, the current decreases in a preset timing sequence according to the stalled rotor discontinuation current strategy. Current, Current; c. Implement a graded response protection strategy for abnormal stall heating function, and maintain the stall heating mode of the motor until the current safely exits.

2. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The , The methods for determining this include: If the stall power of the electric drive system exceeds the stall power limit of the motor sent by the vehicle controller, the initial reference current is proportionally reduced. The range is 0-1.0; otherwise, =1.0; If the electric drive system triggers derating, the initial reference current will be drated. The range is 0-1.0; otherwise, =1.

0.

3. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The option to load based on jitter risk is mentioned. Current, specifically including: The stalled rotor heating enters the given state When the current is applied, verify whether there is fluctuation in motor speed or vibration of the entire vehicle using a test bench or a complete vehicle: If it exists, then the above is given first. Current, to be described After the current reaches the given target value, the given value is then given. Current, wherein, The current amplitude is less than the Current amplitude; If it does not exist, then only the above is given. Electric current.

4. The electric vehicle motor stall heating control method according to claim 3, characterized in that, The stalled rotor heating enters the given state When the current is present, the Current, the The current amplitude settings shall satisfy the following conditions: The The current amplitude is set to meet the power requirements for stall heating of the vehicle's motor; The The current amplitude setting must ensure that there is no fluctuation in motor speed or vibration of the whole vehicle when the motor is stalled.

5. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The stall-out current exit strategy includes: The The current decreases to 0 at a set rate. Or, the stated After the current decreases to 0 at a set rate, the... The current then decreases to 0 at the set rate.

6. The electric vehicle motor stall heating control method according to claim 5, characterized in that, The Current, the The set rate of current decrease must meet the requirements of the vehicle motor stall heating current decrease rate.

7. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The hierarchical response protection strategy for abnormal stall-rotor heating function includes: When the absolute value of the motor speed exceeds the stall heating speed protection threshold at the first set time, a first-level warning fault is triggered; When the actual output power of the motor stall exceeds the rated multiple of the motor stall heating power limit at a second set time, a first-level warning fault is triggered; wherein, the motor stall heating power limit is the minimum value between the motor's own stall power limit and the power limit sent by the vehicle controller.

8. The electric vehicle motor stall heating control method according to claim 5, characterized in that, When the first-level warning fault response is initiated, the current is decreased according to the stall exit current strategy. Current and the Current is applied, and the stall heating mode is maintained.

9. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The stall heating function malfunction also includes a three-level fault response: When the motor controller detects a lost message from the vehicle controller, a verification failure, or a level 3 fault in the electric drive system, it immediately and proactively exits the stall heating function and maintains the stall heating working mode.

10. The electric vehicle motor stall heating control method according to claim 1, characterized in that, The method also includes the vehicle controller detecting the vehicle status in real time: When a Level 3 serious fault is detected in a vehicle component, an EPB caliper is loose, or the motor stall heating function is abnormal, immediately stop sending stall heating mode requests and switch the request mode to send a standby mode request. When the vehicle controller normally exits the stall heating function, it immediately stops sending stall heating mode requests, switches to a standby mode request, and the motor controller, upon receiving the standby mode request, will... Current, the The current is set to 0, and after the current returns to zero, the stall heating mode is exited and the standby mode is switched.

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