A method for handling a slope stall condition of a pure electric vehicle

Abstract

The application provides a kind of pure electric vehicle slope stall operating mode processing method, comprising: obtaining the motor speed and output torque of electric vehicle in slope stall operating mode, if the motor speed is less than the minimum speed threshold of vehicle climbing, the current motor speed is as the first set speed;If the output torque is greater than the maximum torque threshold required by vehicle climbing, it is judged that the vehicle enters the stall state;Obtain motor temperature and IGBT temperature, judge whether the motor temperature and the IGBT temperature reach the first set temperature, if not, control the motor to maintain the current torque output, if yes, control the motor output torque to limit to the first set torque, wherein the first set torque is less than the maximum torque required by climbing, and greater than the minimum torque required by climbing.The application can improve the safety of electric vehicle in slope stall operating mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control of the stall condition of an electric vehicle, in particular to a method for processing the stall condition of a pure electric vehicle on a slope. BACKGROUND

[0002] At present, pure electric vehicles mostly use IGBT to control the current to control the permanent magnet synchronous motor to drive the whole vehicle. IGBT has obvious control advantages, but the disadvantage is that it generates a large amount of heat, especially during high-current control. When the pure electric vehicle is in the stall condition on a slope, the IGBT conducts a large current and generates a large amount of heat, which easily leads to over-temperature of the IGBT and the motor. At this time, the stall condition on the slope needs to be controlled and processed to avoid damage to the IGBT and the motor due to over-temperature. Therefore, it is of great significance to control the stall condition of the electric vehicle by the temperature of the motor and the IGBT. SUMMARY

[0003] The present application provides a method for processing the stall condition of a pure electric vehicle on a slope, which solves the problem that the IGBT and the motor often over-temperature when the existing electric vehicle is in the stall condition on a slope, which easily causes equipment failure. The method can prolong the use time of the stall condition on the slope as much as possible under the premise of protecting the motor and the IGBT from temperature damage, and improve the safety of the electric vehicle in the stall condition on the slope.

[0004] To achieve the above object, the present application provides the following technical scheme:

[0005] A method for processing the stall condition of a pure electric vehicle on a slope, comprising:

[0006] obtaining the motor speed and the output torque of the electric vehicle in the stall condition on the slope, and if the motor speed is less than the minimum speed threshold for vehicle climbing, taking the current motor speed as a first set speed;

[0007] if the output torque is greater than the maximum torque threshold required for vehicle climbing, determining that the vehicle enters the stall state;

[0008] obtaining the motor temperature and the IGBT temperature, and determining whether the motor temperature and the IGBT temperature reach a first set temperature, if not, controlling the motor to maintain the current torque output, and if yes, controlling the motor to limit the output torque to a first set torque, wherein the first set torque is less than the maximum torque required for climbing and greater than the minimum torque required for climbing.

[0009] Preferably, the method further comprises:

[0010] if the motor speed is greater than the first set speed and the motor temperature and the IGBT temperature are both lower than the first set temperature, exiting the stall state, otherwise, controlling the motor to maintain the current torque output.

[0011] Preferably, further comprising:

[0012] A second set speed is set, which is greater than the minimum speed threshold of the vehicle climbing the slope, and if the motor speed is greater than the second set speed, the stall state is exited.

[0013] Preferably, further comprising:

[0014] A second set temperature is set, which is greater than the first set temperature, and whether the motor temperature and the IGBT temperature are both greater than the second set temperature is judged, if yes, the motor output torque is controlled to be limited to a second set torque, and the IGBT switching frequency is limited, wherein the second set torque is less than the minimum torque required by the climbing.

[0015] Preferably, further comprising:

[0016] If the motor temperature and the IGBT temperature are both less than the second set temperature and greater than the first set temperature, the motor is controlled to maintain the current torque output.

[0017] Preferably, further comprising:

[0018] When the output torque of the motor is detected to reach the maximum output torque, timing is started, if the output torque of the motor is continuously the maximum output torque in the process of reaching the first set time length, the output torque of the motor is controlled to be reduced to the target output torque when the timing time length is the first set time length.

[0019] Preferably, further comprising:

[0020] After the timing time length reaches the first set time length, if the output torque of the motor is continuously the target output torque in the process of reaching the second set time length, it is determined that the motor has a stall fault and the stall fault information is reported when the timing time length is the second set time length, wherein the second set time length is greater than the first set time length.

[0021] The application provides a kind of pure electric vehicle slope stall working condition processing method, according to motor temperature and IGBT temperature control motor maintains current torque output or limit to first set torque output.Solve the problem that IGBT and motor overtemperature often occurs when existing electric vehicle is in slope stall working condition, prone to cause equipment failure, can protect motor and IGBT not be damaged under the premise of temperature, as long as possible extend slope stall working condition use time length, improve the safety of electric vehicle in slope stall working condition. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows.

[0023] Figure 1 A pure electric vehicle slope stall condition processing method provided by the present application is shown in the schematic diagram.

[0024] Figure 2 A pure electric vehicle slope stall condition processing logic flow chart provided by the present application is shown in the schematic diagram. DETAILED DESCRIPTION

[0025] In order to make the person in the art better understand the scheme of the embodiments of the present application, the embodiments of the present application are further described in detail below in combination with the drawings and embodiments.

[0026] In order to solve the problem that the IGBT and motor overheat easily and the equipment failure is caused when the existing electric vehicle is in the slope stall condition, the present application provides a pure electric vehicle slope stall condition processing method, which can prolong the use time of the slope stall condition as much as possible under the premise of protecting the motor and IGBT from temperature damage, and improve the safety of the electric vehicle in the slope stall condition.

[0027] As shown in the schematic diagram, a pure electric vehicle slope stall condition processing method comprises: Figure 1 S1: obtaining the motor speed and output torque of the electric vehicle in the slope stall condition, if the motor speed is less than the minimum speed threshold of the vehicle climbing, the current motor speed is taken as the first set speed;

[0028] S2: if the output torque is greater than the maximum torque threshold required by the vehicle climbing, it is determined that the vehicle enters the stall state;

[0029] S3: obtaining the motor temperature and IGBT temperature, and judging whether the motor temperature and the IGBT temperature reach the first set temperature, if not, controlling the motor to maintain the current torque output, if yes, controlling the motor to output the torque limited to the first set torque, wherein the first set torque is less than the maximum torque required by the climbing, and greater than the minimum torque required by the climbing.

[0030]

[0031] ​Specifically, when the electric vehicle is in a hill hold condition, the motor output torque is controlled according to the motor temperature and the IGBT temperature, so that the temperature of the motor and the IGBT does not excessively rise, causing damage. When the motor temperature and the IGBT temperature both reach a first set temperature, the motor output is limited to a first set torque, so that the output torque is limited to the first set torque. When the motor temperature and the IGBT temperature do not reach the first set temperature, the motor is controlled to maintain the current torque output. This method can effectively protect the IGBT and the motor from damage due to excessive temperature in the hill hold condition, while maximizing the hill hold condition usage time.

[0032] The method further includes: if the motor speed is greater than the first set speed, and the motor temperature and the IGBT temperature are both lower than the first set temperature, exiting the stall state, otherwise controlling the motor to maintain the current torque output.

[0033] The method further includes: setting a second set speed, the second set speed being greater than a minimum speed threshold for vehicle climbing, and if the motor speed is greater than the second set speed, exiting the stall state.

[0034] The method further includes: setting a second set temperature, the second set temperature being greater than the first set temperature, and determining whether the motor temperature and the IGBT temperature are both greater than the second set temperature, and if so, controlling the motor output torque to be limited to a second set torque, while limiting the IGBT switching frequency, wherein the second set torque is less than a minimum torque required for climbing.

[0035] The method further includes: if the motor temperature and the IGBT temperature are both less than the second set temperature, and greater than the first set temperature, controlling the motor to maintain the current torque output.

[0036] In an embodiment, as shown in FIG. 1, the processing method includes the following steps: Figure 2

[0037] Step 1: when the speed is lower than the minimum speed required for climbing, the current speed is set as the first set speed n1;

[0038] Step 2: determining the torque, when the torque is greater than the maximum torque required for climbing, entering the stall state;

[0039] Step 3: respectively determining whether the motor temperature and the IGBT temperature reach the first set temperature, if not, maintaining the current torque output, and when any one of the temperatures reaches the first set temperature, limiting the torque to the first set torque;

[0040] ​Step four: judge whether the rotating speed is greater than the first set rotating speed n1, when the rotating speed is greater than the first set rotating speed n1, judge whether the motor temperature and the IGBT temperature are lower than the first set temperature respectively, if both are lower than the first set temperature, exit the locked-rotor state, if both are not lower than the first set temperature, maintain the current torque output, judge whether the rotating speed is greater than the second set rotating speed n2, when the rotating speed is greater than the second set rotating speed n2, exit the locked-rotor state, otherwise maintain the current torque output; when the rotating speed is less than the first set rotating speed, judge whether the motor temperature and the IGBT temperature reach the second set temperature respectively, if both do not reach the second set temperature, maintain the current torque output, judge whether the rotating speed is greater than the second set rotating speed n2, when the rotating speed is greater than the second set rotating speed, exit the locked-rotor state; if both reach the second set temperature, limit the torque to the second set torque and limit the IGBT switching frequency. Repeat step four to judge.

[0041] The first set rotating speed n1 is less than the lowest rotating speed required by climbing, the first set rotating speed n1 is the current motor rotating speed, the second set rotating speed n2 is greater than the lowest rotating speed required by climbing; the first set temperature of the motor and the first set temperature of the IGBT are different, and are T1 and t1 respectively. The second set temperature of the motor and the second set temperature of the IGBT are different, and are T2 and t2 respectively; the first limited torque is less than the maximum torque required by climbing and greater than the minimum torque required by climbing, and the second limited torque is less than the minimum torque required by climbing.

[0042] The method further comprises: when it is detected that the output torque of the motor reaches the maximum output torque, starting timing; if the output torque of the motor is continuously the maximum output torque in the process of reaching the first set timing duration, controlling the motor to reduce the output torque to the target output torque when the timing duration is the first set timing duration.

[0043] The method further comprises: after the timing duration reaches the first set timing duration, if the output torque of the motor is continuously the target output torque in the process of reaching the second set timing duration, determining that the motor has a locked-rotor fault when the timing duration is the second set timing duration, and reporting locked-rotor fault information, wherein the second set timing duration is greater than the first set timing duration.

[0044] It can be seen that the present application provides a kind of slope locked-rotor working condition processing method of pure electric vehicle, according to motor temperature and IGBT temperature control motor maintains current torque output or is limited to the first set torque output.Solve the problem that IGBT and motor overtemperature often occur when existing electric vehicle is in slope locked-rotor working condition, prone to cause equipment failure, can protect motor and IGBT from temperature damage under the premise of as long as possible prolonging the use duration of slope locked-rotor working condition, improve the safety of electric vehicle in slope locked-rotor working condition.

[0045] The structure, features and effects of the present application are described in detail above according to the embodiments shown in the drawings. The above description is only the preferred embodiments of the present application, but the present application is not limited to the embodiments shown in the drawings. Any changes or modifications made according to the concept of the present application, or equivalent embodiments with equivalent changes, are still within the scope of the present application.

Claims

1. A method for handling a slope stall condition of a pure electric vehicle, characterized in that, The method comprises the following steps: acquiring the motor speed and output torque of the electric vehicle in the hill hold mode, if the motor speed is less than the minimum speed threshold required for the vehicle to climb the hill, the current motor speed is taken as the first set speed, and then it is determined whether the output torque is greater than the maximum torque threshold required for the vehicle to climb the hill; if the output torque is greater than the maximum torque threshold required for the vehicle to climb the hill, it is determined that the vehicle enters the stall state; acquiring the motor temperature and IGBT temperature, and determining whether the motor temperature and the IGBT temperature are lower than the first set temperature, if not, the motor maintains the current torque output; if yes, the motor output torque is limited to the first set torque, and then it is determined whether the motor speed is greater than the first set speed; wherein the first set torque is less than the maximum torque required for climbing the hill and greater than the minimum torque required for climbing the hill; if the motor speed is greater than the first set speed, it is determined whether the motor temperature and the IGBT temperature are both lower than the first set temperature; if the motor temperature and the IGBT temperature are both lower than the first set temperature, the stall state is exited, otherwise the motor maintains the current torque output, and it is determined whether the motor speed is greater than the second set speed, if the motor speed is greater than the second set speed, the stall state is exited, wherein the second set speed is greater than the minimum speed threshold required for the vehicle to climb the hill; if the motor speed is less than the first set speed, it is determined whether the motor temperature and the IGBT temperature are both greater than the second set temperature, if yes, the motor output torque is limited to the second set torque, and the IGBT switching frequency is limited, wherein the second set torque is less than the minimum torque required for climbing the hill, and the second set temperature is greater than the first set temperature; if not, the motor maintains the current torque output, and it is determined whether the motor speed is greater than the second set speed, if the motor speed is greater than the second set speed, the stall state is exited.

2. The method according to claim 1, wherein, Further comprising: when the output torque of the motor reaches the maximum output torque, the timing starts; if the output torque of the motor continues to be the maximum output torque during the first set timing, the motor output torque is reduced to the target output torque when the timing reaches the first set timing.

3. The method according to claim 2, characterized in that, Further comprising: after the timing reaches the first set timing, if the motor output torque continues to be the target output torque during the second set timing, it is determined that the motor has a stall fault, and the stall fault information is reported, wherein the second set timing is greater than the first set timing.

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