An electric vehicle control method, device and electric vehicle

Abstract

The application discloses a kind of electric vehicle control method, device and electric vehicle, its method includes: the first power loss of the power device of motor controller is calculated, and the rated junction temperature of the power device is calculated based on the first power loss;The first power loss is the power loss of power device when motor controller output maximum torque;Judge whether vehicle appears coasting, when vehicle appears coasting, enter coasting control mode, and the output torque of motor is dynamically adjusted based on preset time interval and the rated junction temperature.In vehicle coasting, the output torque of motor is dynamically adjusted based on preset time interval and calculated rated junction temperature, accurately adjust motor torque based on different time interval, ensure that torque smooth transition, and ensure that it does not exceed the rated junction temperature of power device, provide sufficient torque to prevent coasting under the premise.

Description

Technical Field

[0001] This invention relates to the field of automotive control technology, and more particularly to an electric vehicle control method, device, and electric vehicle. Background Technology

[0002] Currently, vehicles with only a mechanical handbrake and no EPB (electronic parking brake) are prone to rolling backwards on inclines if not operated promptly, potentially leading to accidents. Therefore, purchasing a vehicle equipped with an EPB is one solution to this problem. However, adding an EPB will inevitably increase vehicle costs.

[0003] Existing vehicle ramp control methods rely on the VCU to determine whether rollback will occur and then adjust the torque to prevent rollback. However, since the power loss of vehicle control devices is not considered during the torque adjustment process, it can easily affect power devices and motor controllers. Summary of the Invention

[0004] This invention provides an electric vehicle control method, device, and electric vehicle to perform hill start control without affecting the service life of power devices and motor controllers.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an electric vehicle control method, comprising:

[0006] Calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; the first power loss is the power loss of the power device when the motor controller outputs the maximum torque;

[0007] The system determines whether the vehicle is slipping. When the vehicle is slipping, it enters the slippage control mode and dynamically adjusts the output torque of the motor based on a preset time interval and the rated junction temperature.

[0008] This invention calculates the power loss of the power devices in the motor controller when outputting maximum torque, and then calculates the rated junction temperature of the power devices based on this power loss. Simultaneously, it determines whether the vehicle will roll backward based on the gear position signal and the vehicle speed. Therefore, when the vehicle rolls backward, it dynamically adjusts the motor's output torque based on a preset time interval and the calculated rated junction temperature. Precise adjustment of the motor torque across different time intervals ensures a smooth torque transition and guarantees sufficient torque to prevent rolling backward without exceeding the rated junction temperature of the power devices.

[0009] Furthermore, the calculation of the first power loss of the power device of the motor controller includes:

[0010] A preset test current is used, and the conduction loss, open-circuit loss, open-circuit loss, and closed-circuit loss of the power device are tested based on the test current.

[0011] The test power loss is calculated based on the conduction loss, the circuit breaking loss, the open tube loss, and the closed tube loss;

[0012] The first power loss is calculated based on the first current, the test current, and the test power loss; the first current is the current value when the power device of the motor controller outputs the maximum torque in the static state when the vehicle speed is zero.

[0013] Furthermore, calculating the rated junction temperature of the power device based on the power loss includes:

[0014] The temperature increment of the power device is calculated based on the first power loss and the junction-case thermal resistance of the power device; the temperature increment is the temperature increment when the vehicle uses the motor for hill-start assist.

[0015] A preset temperature offset is used to calculate the rated junction temperature of the power device based on the maximum junction temperature of the power device, the temperature offset, and the temperature increment.

[0016] Furthermore, the determination of whether the vehicle is slipping, and when the vehicle is slipping, entering the slippage control mode, and dynamically adjusting the motor's output torque based on a preset time interval and the rated junction temperature, includes:

[0017] When the vehicle is rolling downhill, it enters control mode and obtains the rated output torque and maximum output torque of the motor.

[0018] In the control mode, the motor is controlled to output a first torque, which is the output torque of the motor when the vehicle speed is zero.

[0019] The torque output mode is determined based on the first torque, the rated output torque, and the maximum output torque. When the first torque is greater than the rated output torque and less than or equal to the maximum output torque, a dynamic adjustment mode is entered. In the dynamic adjustment mode, the output torque of the motor is dynamically adjusted based on the preset time interval and the rated junction temperature. The torque output mode is determined based on the first torque, the rated output torque, and the maximum output torque, and the output torque of the motor is adjusted based on the torque output mode. The torque output mode includes a constant output mode and a dynamic adjustment mode.

[0020] Furthermore, the step of determining the torque output mode based on the first torque, the rated output torque, and the maximum output torque, and adjusting the motor's output torque based on the torque output mode, includes:

[0021] When the first torque is less than or equal to the rated output torque, the system enters a constant output mode.

[0022] Furthermore, the step of dynamically adjusting the motor's output torque based on the preset time interval and the rated junction temperature in the dynamic adjustment mode includes:

[0023] Within a preset first time interval, the motor is controlled to output a first torque, and a first temperature and a second temperature are recorded; the first temperature is the temperature value of the power device at the beginning of the first time interval, and the second temperature is the temperature value of the power device at the end of the first time interval.

[0024] After the first time interval ends, the output torque of the motor is iteratively adjusted according to the preset second time interval, the preset third time interval, and the fourth time interval in sequence; the duration of the fourth time interval is calculated based on the first time interval, the first temperature, and the second temperature.

[0025] Furthermore, the duration of the fourth time interval is specifically as follows:

[0026]

[0027] Where D1 is the duration of the first time interval, T0 is the first temperature, T1 is the second temperature, and T... s The rated junction temperature is n, which is a preset coefficient.

[0028] Furthermore, the step of iteratively adjusting the motor's output torque according to the preset second time interval, the preset third time interval, and the fourth time interval includes:

[0029] During each iteration, within the second time interval, the output torque of the control motor is linearly reduced to the rated output torque;

[0030] During the third time interval, the motor is controlled to output the rated output torque;

[0031] During the fourth time interval, the motor is controlled to output the first torque.

[0032] Furthermore, the step of iteratively adjusting the motor's output torque according to the preset second time interval, the preset third time interval, and the fourth time interval also includes:

[0033] At the end of the fourth time interval, the next iteration process begins, and the iteration continues until the preset number of iterations is reached, at which point the iteration stops and the motor is controlled to output a constant rated output torque.

[0034] Furthermore, determining whether the vehicle is slipping includes:

[0035] Real-time monitoring of vehicle speed and gear position signals, and determination of whether the vehicle is slipping on a slope based on the vehicle speed and gear position signals;

[0036] When the direction of the vehicle's speed is the same as the direction of the gear, the vehicle is not rolling backwards; when the direction of the vehicle's speed is not the same as the direction of the gear, the vehicle is rolling backwards.

[0037] In a second aspect, the present invention provides an electric vehicle control device, comprising: a rated junction temperature calculation module, a runaway judgment module, and a control module;

[0038] The rated junction temperature calculation module is used to calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; the first power loss is the power loss of the power device when the motor controller outputs the maximum torque;

[0039] The slope slip judgment and control module is used to determine whether the vehicle is slipping. When the vehicle is slipping, it enters the slope slip control mode and dynamically adjusts the output torque of the motor based on the preset time interval and the rated junction temperature. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating an electric vehicle control method provided in an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of the structure of an electric vehicle control device provided in an embodiment of the present invention. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0043] The terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0044] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0045] Example 1

[0046] See Figure 1 , Figure 1 This is a flowchart illustrating an electric vehicle control method according to an embodiment of the present invention. The embodiment of the present invention provides an electric vehicle control method, including steps 101 to 102, as detailed below:

[0047] Step 101: Calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; the first power loss is the power loss of the power device when the motor controller outputs the maximum torque;

[0048] In this embodiment, the calculation of the first power loss of the power device of the motor controller includes:

[0049] A preset test current is used, and the conduction loss, open-circuit loss, open-circuit loss, and closed-circuit loss of the power device are tested based on the test current.

[0050] The test power loss is calculated based on the conduction loss, the circuit breaking loss, the open tube loss, and the closed tube loss;

[0051] The first power loss is calculated based on the first current, the test current, and the test power loss; the first current is the current value when the power device of the motor controller outputs the maximum torque in the static state when the vehicle speed is zero.

[0052] In this embodiment, the first power loss of the power devices is calculated when the motor controller outputs maximum torque. This first power loss is an important parameter for evaluating the operating state of the motor controller, and it directly affects the temperature and lifespan of the power devices.

[0053] In this embodiment, the power loss P of the motor controller power device at maximum torque output is calculated under the condition that the vehicle is stationary (vehicle speed is zero). max Specifically:

[0054] P max =P test ×(I max / I test ) 2 (1)

[0055] Among them, I max This is the first current, which is the current value when the motor controller power device outputs maximum torque under the condition that the vehicle is stationary (vehicle speed is zero). max Obtained through bench calibration tests.

[0056] In this embodiment, a preset test current is used to control the power device under test current I. test The conduction loss P1 and the power device under the test current I test The circuit breaking loss P2 and the power device under the test current I test The losses P3 and power devices during the turn-on process under test current I test The losses P4 during the closed-loop process are calculated, and the first power loss is calculated based on these losses. The first power loss is as follows:

[0057] P test =(P1+P2+P3+P4) (2)

[0058] In this embodiment, the first power loss of the test current is calculated based on the power loss of the power device under different operating conditions, which ensures the accurate assessment of the power device loss of the motor controller and provides basic data for subsequent temperature management.

[0059] In this embodiment, calculating the rated junction temperature of the power device based on the power loss includes:

[0060] The temperature increment of the power device is calculated based on the first power loss and the junction-case thermal resistance of the power device; the temperature increment is the temperature increment when the vehicle uses the motor for hill-start assist.

[0061] A preset temperature offset is used to calculate the rated junction temperature of the power device based on the maximum junction temperature of the power device, the temperature offset, and the temperature increment.

[0062] In this embodiment, the temperature increment ΔT when the vehicle uses the motor for hill-start assist is calculated. Specifically, this temperature increment is:

[0063] △T=P max ×R (3)

[0064] Where R is the junction-to-case thermal resistance of the power device in the motor controller, which is obtained by testing the power device under adiabatic conditions.

[0065] In this embodiment, the rated junction temperature T of the power device is calculated based on the maximum junction temperature of the power device, the temperature offset, and the temperature increment. s Specifically:

[0066] T s = k×T max - △T- △T′ (4)

[0067] Among them, T max is the maximum junction temperature of the power device in the motor controller, i.e., the maximum allowable junction temperature; k is the preset junction temperature empirical coefficient, with a value range of 0.5-0.95; △T′ is the preset temperature offset, with a value range of 0-10℃.

[0068] In this embodiment, the maximum permissible junction temperature of the power devices in the motor controller can be obtained by consulting the datasheet or specification sheet of the power appliance. In this embodiment, the power devices in the motor controller include MOSFETs, diodes, IGBTs, etc.

[0069] In this embodiment, by calculating the first power loss, the power device losses of the motor controller when outputting maximum torque can be accurately assessed. Based on the first power loss, the rated junction temperature of the power device is calculated, ensuring that the power device operates within a safe temperature range and avoiding damage due to overheating. This achieves refined management of the power device losses and temperature of the motor controller when outputting maximum torque, ensuring that the power device operates within a safe temperature range, thereby improving the reliability and safety of the entire vehicle and reducing the risk of damage due to overheating.

[0070] Step 102: Determine if the vehicle is rolling backwards. If the vehicle is rolling backwards, enter the rolling backwards control mode and dynamically adjust the output torque of the motor based on the preset time interval and the rated junction temperature.

[0071] In this embodiment, determining whether the vehicle has rolled away includes:

[0072] Real-time monitoring of vehicle speed and gear position signals, and determination of whether the vehicle is slipping on a slope based on the vehicle speed and gear position signals;

[0073] When the direction of the vehicle's speed is the same as the direction of the gear, the vehicle is not rolling backwards; when the direction of the vehicle's speed is not the same as the direction of the gear, the vehicle is rolling backwards.

[0074] In this embodiment, the vehicle speed, torque, accelerator pedal signal, and gear signal are monitored in real time. When the accelerator pedal is depressed and effective, the vehicle receives the accelerator pedal signal, which includes the accelerator pedal opening. When the accelerator pedal is depressed and effective, the VCU (Vehicle Control Unit) controls the motor to output torque M and records the output torque M.

[0075] In this embodiment, the vehicle speed and gear position signal are used to determine whether the vehicle is rolling backwards. When the direction of the vehicle speed is the same as the direction of the vehicle gear position, the vehicle is not rolling backwards. In the non-rolling backwards state, the VCU controls the motor to output torque M as it does under normal conditions.

[0076] In this embodiment, if the vehicle speed direction is opposite to the vehicle gear direction, the VCU determines that the vehicle is in a rolling state.

[0077] In this embodiment, the vehicle speed, torque, accelerator pedal signal, and gear signal are monitored in real time. Based on the vehicle speed and gear signals, it is determined whether the vehicle is slipping on a slope and the slipping state is quickly identified, thereby quickly adjusting the motor output torque to prevent the vehicle from slipping on a slope.

[0078] In this embodiment, if the vehicle speed direction is opposite to the vehicle gear direction, the VCU determines that the vehicle is in a rolling state. When the vehicle is in a rolling state, it enters the control mode. At this time, the VCU controls the torque output value to be rapidly increased to the value M0 when the vehicle speed is zero, that is, the first torque M0.

[0079] In this embodiment, determining whether the vehicle is slipping, and when the vehicle is slipping, entering a slippage control mode, and dynamically adjusting the motor's output torque based on a preset time interval and the rated junction temperature, includes:

[0080] When the vehicle is rolling downhill, it enters control mode and obtains the rated output torque and maximum output torque of the motor.

[0081] In the control mode, the motor is controlled to output a first torque, which is the output torque of the motor when the vehicle speed is zero.

[0082] The torque output mode is determined based on the first torque, the rated output torque, and the maximum output torque; when the first torque is greater than the rated output torque and less than or equal to the maximum output torque, the motor enters a dynamic adjustment mode, in which the output torque of the motor is dynamically adjusted based on the preset time interval and the rated junction temperature.

[0083] In this embodiment, based on the first torque M0 and the rated output torque M n The maximum output torque M max Determine the torque output mode, which includes a constant output mode and a dynamic adjustment mode.

[0084] In this embodiment, when it is determined that the vehicle is slipping on a slope, the slope slip control mode is entered, and the rated output torque and maximum output torque of the motor are obtained. Based on the first torque, rated output torque, and maximum output torque, a torque output mode is determined, and the motor's output torque is dynamically adjusted. By dynamically adjusting the torque output, it is ensured that the vehicle will not slip when starting on a slope, while also avoiding excessive torque that could overload the power devices.

[0085] In this embodiment,

[0086] The determination of the torque output mode based on the first torque, the rated output torque, and the maximum output torque includes:

[0087] When the first torque is less than or equal to the rated output torque, the system enters a constant output mode.

[0088] In this embodiment, the motor is controlled to continuously output the first torque in the constant output mode;

[0089] In this embodiment, when the first torque is less than or equal to the rated output torque, i.e., M0 ≤ M n When the constant output mode is entered, the VCU controls the motor to maintain the first torque M0 output.

[0090] In this embodiment, when the first torque is greater than the rated output torque and less than or equal to the maximum output torque, i.e., M n <M0≤M max When the motor torque is adjusted, it enters dynamic adjustment mode and dynamically adjusts the motor torque based on dynamic adjustment rules.

[0091] In this embodiment, the dynamic adjustment rule includes iteratively adjusting the output torque of the motor based on the preset time interval and the rated junction temperature in the dynamic adjustment mode.

[0092] In this embodiment, the step of iteratively adjusting the motor's output torque based on the preset time interval and the rated junction temperature in the dynamic adjustment mode includes:

[0093] Within a preset first time interval, the motor is controlled to output a first torque, and a first temperature and a second temperature are recorded; the first temperature is the temperature value of the power device at the beginning of the first time interval, and the second temperature is the temperature value of the power device at the end of the first time interval.

[0094] After the first time interval ends, the motor's output torque is iteratively adjusted according to the preset second, third, and fourth time intervals. The fourth time interval is calculated based on the first time interval, the first temperature, and the second temperature. In this embodiment, the duration D1 of the preset first time interval is set to 10-10000 ms, t0 is the start time of the first time interval, and t1 is the end time of the first time interval. During the first time interval t0-t1, the motor outputs a first torque M0. The first temperature T0 and the second temperature T1 are recorded. T0 is the temperature value of the motor controller power device monitored at time t0, and T1 is the temperature value of the motor controller power device monitored at time t1.

[0095] In this embodiment, the duration D2 of the second time interval is preset, and its value is 10-5000ms; the duration D3 of the third time interval is preset, and its value is 10-10000ms; and the fourth time interval is calculated based on the first time interval, the first temperature, and the second temperature.

[0096] In this embodiment, the duration of the fourth time interval is specifically as follows:

[0097]

[0098] Where t1 is the duration of the first time interval, T0 is the first temperature, T1 is the second temperature, and T s The rated junction temperature is n, which is a preset coefficient.

[0099] In this embodiment, n is set to 3 by default.

[0100] In this embodiment, after the first time interval ends, the output torque of the motor is iteratively adjusted according to the preset second time interval, the preset third time interval, and the fourth time interval.

[0101] In this embodiment, the step of iteratively adjusting the motor's output torque according to a preset second time interval, a preset third time interval, and a preset fourth time interval includes:

[0102] During each iteration, within the second time interval, the output torque of the control motor is linearly reduced to the rated output torque;

[0103] During the third time interval, the motor is controlled to output the rated output torque;

[0104] During the fourth time interval, the motor is controlled to output the first torque.

[0105] In this embodiment, the step of iteratively adjusting the motor's output torque according to a preset second time interval, a preset third time interval, and a fourth time interval further includes:

[0106] At the end of the fourth time interval, the next iteration process begins, and the iteration continues until the preset number of iterations is reached, at which point the iteration stops and the motor is controlled to output a constant rated output torque.

[0107] In this embodiment, the start time of each time interval is the end time of the previous time interval. The motor torque is dynamically adjusted according to each time interval. In the first time interval, a first torque is output, and the temperature at the start and end times is recorded, along with the temperature changes of the power devices, to understand the temperature rise trend and provide basic data for subsequent adjustments. In the second time interval, the motor torque is linearly reduced to the rated output torque to achieve a smooth torque transition. In the third time interval, the motor outputs the rated output torque to ensure the system operates within a safe range. In the fourth time interval, the motor outputs the first torque again, and temperature and torque changes are monitored again. By gradually adjusting the motor's output torque and monitoring the temperature changes of the power devices in real time, it is ensured that they remain within the safe operating temperature range.

[0108] In this embodiment, the output torque of the motor is iteratively adjusted according to the preset first time interval, the preset second time interval, the preset third time interval, and the fourth time interval. After the first iteration process is completed, the vehicle issues a slope slip warning.

[0109] In this embodiment, a slope slip warning is played based on the vehicle's voice system, specifically: "Vehicle slipping on slope, please brake immediately and pay attention to safety."

[0110] In this embodiment, the number of iterations is set to two. During each iteration, the temperature of the power device is monitored in real time to ensure that it does not exceed the rated junction temperature. By gradually adjusting the torque, the power device is prevented from bearing excessive load in a short period of time. If the number of iterations has not reached two by the end of the fourth time interval, the iteration adjustment continues until the number of iterations reaches two. Then, the iteration stops and the rated output torque is kept constant to avoid damage to the device.

[0111] In this embodiment, by dividing the torque adjustment process into several time intervals for iterative adjustment, a smooth transition and refined management of torque output are achieved. This not only improves the smoothness and comfort of driving, but also ensures that the motor and power devices operate within a safe operating range, preventing overheating and damage, and ultimately achieving the goal of optimizing energy use and extending equipment life.

[0112] Please refer to Figure 2 , Figure 2A schematic diagram of an electric vehicle control device provided in an embodiment of the present invention includes: a rated junction temperature calculation module 201 and a runaway control module 202;

[0113] The rated junction temperature calculation module 201 is used to calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; the first power loss is the power loss of the power device when the motor controller outputs the maximum torque.

[0114] The slope control module 202 is used to determine whether the vehicle is slipping. When the vehicle is slipping, it enters the slope control mode and dynamically adjusts the output torque of the motor based on the preset time interval and the rated junction temperature.

[0115] In this embodiment, the rated junction temperature calculation module 201 is used for:

[0116] A preset test current is used, and the conduction loss, open-circuit loss, open-circuit loss, and closed-circuit loss of the power device are tested based on the test current.

[0117] The test power loss is calculated based on the conduction loss, the circuit breaking loss, the open tube loss, and the closed tube loss;

[0118] The first power loss is calculated based on the first current, the test current, and the test power loss; the first current is the current value when the power device of the motor controller outputs the maximum torque in the static state when the vehicle speed is zero.

[0119] In this embodiment, the rated junction temperature calculation module 201 is used for:

[0120] The temperature increment of the power device is calculated based on the first power loss and the junction-case thermal resistance of the power device; the temperature increment is the temperature increment when the vehicle uses the motor for hill-start assist.

[0121] A preset temperature offset is used to calculate the rated junction temperature of the power device based on the maximum junction temperature of the power device, the temperature offset, and the temperature increment.

[0122] In this embodiment, the slope control module 202 is used for:

[0123] When the vehicle is rolling downhill, it enters control mode and obtains the rated output torque and maximum output torque of the motor.

[0124] In the control mode, the motor is controlled to output a first torque, which is the output torque of the motor when the vehicle speed is zero.

[0125] The torque output mode is determined based on the first torque, the rated output torque, and the maximum output torque; when the first torque is greater than the rated output torque and less than or equal to the maximum output torque, a dynamic adjustment mode is entered, in which the motor's output torque is dynamically adjusted based on the preset time interval and the rated junction temperature. In this embodiment, the slope control module 202 is used for:

[0126] When the first torque is less than or equal to the rated output torque, the system enters a constant output mode.

[0127] In this embodiment, the slope control module 202 is used for:

[0128] Within a preset first time interval, the motor is controlled to output a first torque, and a first temperature and a second temperature are recorded; the first temperature is the temperature value of the power device at the beginning of the first time interval, and the second temperature is the temperature value of the power device at the end of the first time interval.

[0129] After the first time interval ends, the output torque of the motor is iteratively adjusted according to the preset second time interval, the preset third time interval, and the fourth time interval in sequence; the fourth time interval is calculated based on the first time interval, the first temperature, and the second temperature.

[0130] In this embodiment, the slope control module 202 is used for:

[0131] During each iteration, within the second time interval, the output torque of the control motor is linearly reduced to the rated output torque;

[0132] During the third time interval, the motor is controlled to output the rated output torque;

[0133] During the fourth time interval, the motor is controlled to output the first torque.

[0134] In this embodiment, the slope control module 202 is used for:

[0135] At the end of the fourth time interval, the next iteration process begins, and the iteration continues until the preset number of iterations is reached, at which point the iteration stops and the motor is controlled to output a constant rated output torque.

[0136] In this embodiment of the invention, an electric vehicle is also provided, including a controller, which performs slope control according to the electric vehicle control method described above.

[0137] In this embodiment of the invention, a computer-readable storage medium is also provided, which includes a stored computer program, wherein the computer program controls the device where the computer-readable storage medium is located to execute the above-described electric vehicle control method when it is running.

[0138] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for controlling an electric vehicle, characterized in that, include: Calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; The first power loss is the power loss of the power device when the motor controller outputs the maximum torque; The system determines whether the vehicle is rolling backwards. When the vehicle is rolling backwards, it enters a rollback control mode and dynamically adjusts the motor's output torque based on a preset time interval and the rated junction temperature. This includes: when the vehicle is rolling backwards, entering the control mode and acquiring the motor's rated output torque and maximum output torque; in the control mode, controlling the motor to output a first torque, which is the motor's output torque when the vehicle speed is zero; determining a torque output mode based on the first torque, the rated output torque, and the maximum output torque; when the first torque is greater than the rated output torque and less than or equal to the maximum output torque, entering a dynamic adjustment mode, in which the motor's output torque is dynamically adjusted based on the preset time interval and the rated junction temperature.

2. The electric vehicle control method as described in claim 1, characterized in that, The calculation of the first power loss of the power device of the motor controller includes: A preset test current is used, and the conduction loss, open-circuit loss, open-circuit loss, and closed-circuit loss of the power device are tested based on the test current. The test power loss is calculated based on the conduction loss, the circuit breaking loss, the open tube loss, and the closed tube loss; The first power loss is calculated based on the first current, the test current, and the test power loss; the first current is the current value when the power device of the motor controller outputs the maximum torque in the static state when the vehicle speed is zero.

3. The electric vehicle control method as described in claim 2, characterized in that, The calculation of the rated junction temperature of the power device based on the first power loss includes: The temperature increment of the power device is calculated based on the first power loss and the junction-case thermal resistance of the power device; the temperature increment is the temperature increment when the vehicle uses the motor for hill-start assist. A preset temperature offset is used to calculate the rated junction temperature of the power device based on the maximum junction temperature of the power device, the temperature offset, and the temperature increment.

4. The electric vehicle control method as described in claim 3, characterized in that, The determination of the torque output mode based on the first torque, the rated output torque, and the maximum output torque includes: When the first torque is less than or equal to the rated output torque, the system enters a constant output mode.

5. The electric vehicle control method as described in claim 3, characterized in that, The dynamic adjustment of the motor's output torque based on the preset time interval and the rated junction temperature in the dynamic adjustment mode includes: Within a preset first time interval, the motor is controlled to output a first torque, and a first temperature and a second temperature are recorded; the first temperature is the temperature value of the power device at the beginning of the first time interval, and the second temperature is the temperature value of the power device at the end of the first time interval. After the first time interval ends, the output torque of the motor is iteratively adjusted according to the preset second time interval, the preset third time interval, and the fourth time interval in sequence; the duration of the fourth time interval is calculated based on the duration of the first time interval, the first temperature, and the second temperature.

6. The electric vehicle control method as described in claim 5, characterized in that, The duration of the fourth time interval is as follows: in, The first time interval is the duration of the first time interval, T0 is the first temperature, T1 is the second temperature, and T... s The rated junction temperature is n, which is a preset coefficient.

7. The electric vehicle control method as described in claim 6, characterized in that, The step of iteratively adjusting the motor's output torque according to a preset second time interval, a preset third time interval, and a preset fourth time interval includes: During each iteration, within the second time interval, the output torque of the control motor is linearly reduced to the rated output torque; During the third time interval, the motor is controlled to output the rated output torque; During the fourth time interval, the motor is controlled to output the first torque.

8. The electric vehicle control method as described in claim 7, characterized in that, The step of iteratively adjusting the motor's output torque according to a preset second time interval, a preset third time interval, and a preset fourth time interval also includes: At the end of the fourth time interval, the next iteration process begins, and the iteration continues until the preset number of iterations is reached, at which point the iteration stops and the motor is controlled to output a constant rated output torque.

9. An electric vehicle control method according to any one of claims 1 to 8, characterized in that, The determination of whether a vehicle is slipping includes: Real-time monitoring of vehicle speed and gear position signals, and determination of whether the vehicle is slipping on a slope based on the vehicle speed and gear position signals; When the direction of the vehicle's speed is the same as the direction of the vehicle's gear, the vehicle is not rolling backwards; when the direction of the vehicle's speed is not the same as the direction of the vehicle's gear, the vehicle is rolling backwards.

10. An electric vehicle control device, characterized in that, include: Rated junction temperature calculation module and runoff control module; The rated junction temperature calculation module is used to calculate the first power loss of the power device of the motor controller, and calculate the rated junction temperature of the power device based on the first power loss; the first power loss is the power loss of the power device when the motor controller outputs the maximum torque; The roll-off control module is used to determine whether the vehicle is rolling downhill. When the vehicle is rolling downhill, it enters the roll-off control mode and dynamically adjusts the motor's output torque based on a preset time interval and the rated junction temperature. This includes: when the vehicle is rolling downhill, entering the control mode and acquiring the motor's rated output torque and maximum output torque; in the control mode, controlling the motor to output a first torque, which is the motor's output torque when the vehicle speed is zero; determining a torque output mode based on the first torque, the rated output torque, and the maximum output torque; when the first torque is greater than the rated output torque and less than or equal to the maximum output torque, entering the dynamic adjustment mode, in which the motor's output torque is dynamically adjusted based on the preset time interval and the rated junction temperature.

11. An electric vehicle, characterized in that, Includes a controller that performs slope control according to an electric vehicle control method as described in any one of claims 1 to 9.

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