Motor torque zero-crossing response control strategy and electronic equipment for electric vehicles

Abstract

The present application discloses a motor torque zero-crossing response control strategy for electric vehicles, comprising the following steps: a motor controller MCU calculates the absolute value DT of the torque difference between the torque command T1 issued by the vehicle controller VCU and the actual output torque T2 of the motor in the previous cycle; the absolute value DT of the torque difference is compared with a torque difference classification table to obtain a torque difference level and a torque adjustment function corresponding to the level, wherein the torque adjustment function includes three different stage adjustment functions, and the torque adjustment time dt of the three different stage adjustment functions and the absolute value Tc of the adjusted torque difference are adjusted according to the torque difference level; the actual output torque T2 of the motor in the previous cycle is adjusted to the torque command T1 issued by the vehicle controller VCU according to the three different stage adjustment functions. This strategy can not only reduce the gear rattling phenomenon caused by accelerating and releasing the accelerator when the vehicle starts and drives, but also shortens the debugging time, making it more efficient and convenient.

Description

Technical Field

[0001] The present application relates to the field of new energy vehicle technology, and specifically to a motor torque zero-crossing response control strategy and electronic equipment for electric vehicles. Background Art

[0002] When the speed of electric vehicles changes, gear rattling is prone to occur, which not only causes the crown part of the gear to wear faster, but when the gear rattling phenomenon occurs repeatedly over a long period of time, the right-angled crown of the gear will be severely worn or even ground into a fillet, causing damage to the vehicle. In addition, when the gear rattling phenomenon occurs, the vehicle will shake abnormally, seriously reducing the driving comfort of the vehicle. At present, the method of avoiding gear rattling is usually to change the zero-crossing torque response speed from fast to slow to reduce the impact and collision between gears and thus reduce gear rattling. However, in the actual debugging process, there are many parameters to be adjusted, resulting in a long debugging time. Therefore, there is an urgent need for a motor torque zero-crossing response control strategy for electric vehicles that can avoid gear rattling and reduce debugging time to solve the above problems. Summary of the Invention

[0003] The present application provides a motor torque zero-crossing response control strategy and electronic equipment for electric vehicles, which can avoid gear knocking and reduce debugging time.

[0004] The technical solution adopted by the present application to solve the technical problem is to provide a motor torque zero-crossing response control strategy for electric vehicles, including the following steps:

[0005] Step 1: The motor controller MCU obtains the actual output torque T2 of the motor in the previous cycle and the torque command T1 issued by the vehicle controller VCU;

[0006] Step 2: The motor controller MCU calculates the absolute value DT of the torque difference between the torque command T1 issued by the vehicle controller VCU and the actual output torque T2 of the motor in the previous cycle;

[0007] Step 3: Comparing the absolute value of the torque difference DT with a torque difference classification table to obtain a torque difference level and a torque adjustment function corresponding to the level. The torque adjustment function includes three different stage adjustment functions. The torque adjustment time dt and the absolute value of the adjusted torque difference Tc of the three different stage adjustment functions are adjusted according to the torque difference level.

[0008] Step 4: According to the stage adjustment function of the first stage, the actual output torque T2 of the motor in the previous cycle is adjusted to the preset transition torque Ts within the time range dt1;

[0009] Step 5: In the second stage, the torque difference is adjusted to zero by the adjustment function, and the actual output torque of the current motor is kept unchanged at Ts within the time range dt2;

[0010] Step 6: According to the stage adjustment function of the third stage, the current actual output torque Ts of the motor is adjusted to the torque command T1 issued by the vehicle controller VCU within the time range dt3.

[0011] Preferably, in step three, the torque difference levels in the torque difference grading table are sorted in ascending order according to the torque difference level corresponding to the increase in the torque difference, the torque difference corresponding to a higher level is greater than the torque difference corresponding to a lower level, and the difference in the torque differences of adjacent levels gradually increases. When the absolute value DT of the torque difference cannot uniquely correspond to the torque difference in the torque difference grading table, the higher level between the torque difference levels where the absolute value DT of the torque difference is located and the torque adjustment function corresponding to the level are taken to perform torque adjustment.

[0012] Preferably, in step 3, the torque adjustment function includes three different stage adjustment functions, and the torque adjustment time dt and the absolute value Tc of the adjusted torque difference of the three different stage adjustment functions are adjusted according to the torque difference level, specifically including:

[0013] The torque adjustment function includes three different stage adjustment functions, wherein, as the torque difference level increases, the torque adjustment time dt1 and the absolute value of the adjusted torque difference Tc1 in the first stage first increase and then decrease; the torque adjustment time dt2 of the stage adjustment function in the second stage increases, and the absolute value of the torque difference adjusted by the adjustment function Tc2 is zero, and dt2 is controlled within 0.8-1.1s; the torque adjustment time dt3 of the third stage increases, and the absolute value of the adjusted torque difference Tc3 remains unchanged.

[0014] Preferably, the stage adjustment function of the first stage is: T1s=k1t n +b, T1s represents the actual output torque value of the current motor at time t, t≤t1, 0<k1<3, the value of b is consistent with the value of the actual output torque T2 of the motor in the previous cycle, and t1 is the adjustment duration of the stage adjustment function of the first stage.

[0015] Preferably, the stage adjustment function of the second stage is: T2s=k1t1 n +b, T2s represents the actual output torque value of the current motor at time t1, and T2s is consistent with the preset transition torque Ts value. The torque adjustment time of the stage adjustment function in the second stage is dt2.

[0016] Preferably, the stage adjustment function of the third stage is T3s=k2t+b, where T3s represents the actual output torque value of the current motor at time t, 0<k2<0.5, t2<t≤t3, and the value of b is consistent with the value of the actual output torque T2 of the motor in the previous cycle. When t=t3, the value of T3s is consistent with the torque command T1 issued by the vehicle controller VCU.

[0017] Preferably, the preset transition torque Ts is used to slowly change the direction of the tooth side clearance, which is related to the actual situation of the equipment. The preset transition torque Ts needs to be calibrated on the actual vehicle, and the absolute value of the preset transition torque Ts is controlled within 0-10 Nm.

[0018] Preferably, the preset transition torque Ts is related to the vehicle lubrication method, lubrication state, gear weight, inter-tooth clearance and gear material. The lubrication method can be obtained and represented by the coefficient Kl. The lubrication state and the size of the inter-tooth clearance are both represented by the total running time of the vehicle and represented by the calculation formula of the correction amount ΔTc. The calculation formula is: ΔTc=(1+Kw*tw / t_life_max), t_life_max can be abbreviated as tmax, which represents the design life of the equipment, tw is the running time of the equipment, Kw is the amplification factor, Kw>1, and the recommended value is [1.1,1.2];

[0019] The gear weight and material are characterized by the rated maximum working torque of the gear. The rated maximum working torque Tw is multiplied by the scaling factor Ks. The scaling factor Ks is less than 1 and is a preset constant value. The recommended value is Ks = 0.001 to 0.01. When the gear shaft and gear bearing are lubricated with oil, Kl = 1. When the gear shaft and gear bearing are lubricated with lubricating grease or connected through bearings, Kl = 1.05.

[0020] Ts=Tw*Ks*Kl*△Tc.

[0021] An electronic device includes a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement any one of the motor torque zero-crossing response control strategies for electric vehicles as described above.

[0022] The substantial effects of this application are:

[0023] (1) The motor torque zero-crossing response control strategy for electric vehicles uses the absolute value DT of the torque difference between the current torque command and the actual output torque of the motor in the previous cycle as the classification basis, matches the corresponding torque adjustment function according to the actual adjusted absolute value of the torque difference, and adjusts the torque by segmenting the torque adjustment function. This has stronger adaptability, slows down the occurrence of tooth-striking and can reduce debugging time.

[0024] (2) The motor torque zero-crossing response control strategy for electric vehicles adjusts the torque adjustment time of the torque adjustment function at different stages and the absolute value of the adjusted torque difference by adjusting the absolute value of the torque difference DT, which is more in line with reality and can effectively slow down the occurrence of tooth-striking.

[0025] (3) The torque difference adjusted by the second stage adjustment function of the motor torque zero-crossing response control strategy for electric vehicles is zero, and the actual output torque of the current motor is kept unchanged at Ts within the time range dt2. The preset transition torque Ts is used to slowly change the direction of the tooth side clearance. The absolute value of the preset transition torque Ts is controlled within 0-10 Nm, which can effectively slow down the occurrence of tooth rattling. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flowchart of the method steps in Example 1 of this application;

[0027] Figure 2 This is a schematic diagram of the motor torque change in the second embodiment of the present application. DETAILED DESCRIPTION

[0028] The technical solution of the present application is further described below through specific embodiments.

[0029] Example 1

[0030] like Figure 1 As shown, an embodiment of the motor torque zero-crossing response control strategy for electric vehicles includes the following steps:

[0031] Step 1: The motor controller MCU obtains the actual output torque T2 of the motor in the previous cycle and the torque command T1 issued by the vehicle controller VCU;

[0032] Step 2: The motor controller MCU calculates the absolute value DT of the torque difference between the torque command T1 issued by the vehicle controller VCU and the actual output torque T2 of the motor in the previous cycle;

[0033] Step 3: Comparing the absolute value of the torque difference DT with a torque difference classification table to obtain a torque difference level and a torque adjustment function corresponding to the level. The torque adjustment function includes three different stage adjustment functions. The torque adjustment time dt and the absolute value of the adjusted torque difference Tc of the three different stage adjustment functions are adjusted according to the torque difference level.

[0034] Step 4: According to the stage adjustment function of the first stage, the actual output torque T2 of the motor in the previous cycle is adjusted to the preset transition torque Ts within the time range dt1;

[0035] Step 5: In the second stage, the torque difference is adjusted to zero by the adjustment function, and the actual output torque of the current motor is kept unchanged at Ts within the time range dt2;

[0036] Step 6: According to the stage adjustment function of the third stage, the current actual output torque Ts of the motor is adjusted to the torque command T1 issued by the vehicle controller VCU within the time range dt3.

[0037] First, the motor torque zero-crossing response control strategy for electric vehicles uses the absolute value DT of the torque difference between the current torque command and the actual output torque of the motor in the previous cycle as the classification basis, matches the corresponding torque adjustment function according to the actual adjusted absolute value of the torque difference, and adjusts the torque by segmenting the torque adjustment function, which is more adaptable. Secondly, the torque adjustment time of the torque adjustment function at different stages and the absolute value of the adjusted torque difference are adjusted according to the size of the absolute value DT of the torque difference, which is more in line with reality and can effectively slow down the occurrence of tooth rattling.

[0038] It should be noted that, after multiple tests and verifications, by extracting the absolute values of multiple measured torque differences and using the same adjustment function for torque adjustment multiple times, it was found that within a certain range of absolute values of torque differences, the same adjustment function can achieve the same effect of slowing down the occurrence of tooth tapping. Therefore, a torque difference grading table is compiled based on this. The torque difference grading table includes n levels, and the torque difference levels are sorted in ascending order according to the torque difference levels corresponding to the increase in the absolute value of the torque difference. The absolute value of the torque difference corresponding to the high level is greater than the absolute value of the torque difference corresponding to the low level, that is, the absolute value of the torque difference corresponding to the n-1 level is less than the absolute value of the torque difference corresponding to the n level, and the difference between the absolute values of the torque differences of adjacent levels gradually increases. When the absolute value DT of the torque difference cannot uniquely correspond to the absolute value of the torque difference in the torque difference grading table, the higher level between the torque difference levels where the absolute value DT of the torque difference is located and the torque adjustment function corresponding to the level are taken to perform torque adjustment.

[0039] Furthermore, through actual measurements, it was found that as the torque difference level increases, the torque adjustment time dt1 of the first stage and the absolute value of the adjusted torque difference Tc1 first increase and then decrease; the torque adjustment time dt2 of the stage adjustment function of the second stage increases, and the absolute value of the torque difference adjusted by the adjustment function Tc2 is zero, and dt2 is controlled at 0.8-1.1s; the torque adjustment time dt3 of the third stage increases, and the absolute value of the adjusted torque difference Tc3 remains unchanged. Using the above three different stage adjustment functions to adjust the torque in turn can effectively slow down the occurrence of tooth chattering.

[0040] Example 2

[0041] An embodiment of a motor torque zero-crossing response control strategy for an electric vehicle includes the following steps:

[0042] Step 1: The motor controller MCU obtains the actual output torque T2 of the motor in the previous cycle and the torque command T1 issued by the vehicle controller VCU;

[0043] Step 2: The motor controller MCU calculates the absolute value DT of the torque difference between the torque command T1 issued by the vehicle controller VCU and the actual output torque T2 of the motor in the previous cycle;

[0044] Step 3: Compare the absolute value of the torque difference DT to the torque difference classification table to obtain the torque difference level and the torque adjustment function corresponding to the level. The torque adjustment function includes three different stage adjustment functions. The torque adjustment time dt and the absolute value of the adjusted torque difference Tc of the three different stage adjustment functions are adjusted according to the torque difference level, as shown in FIG. Figure 2 As shown, the stage adjustment function of the first stage is, T1s = k1t n +b, T1s represents the actual output torque value of the current motor at time t, t≤t1, 0<k1<3, the value of b is consistent with the actual output torque T2 of the motor in the previous cycle, t1 is the adjustment duration of the stage adjustment function of the first stage; the stage adjustment function of the second stage is, T2s=k1t1 n +b, T2s represents the actual output torque value of the current motor at time t1, and T2s is consistent with the preset transition torque Ts value. The torque adjustment time of the stage adjustment function of the second stage is dt2; the stage adjustment function of the third stage is, T3s=k2t+b, T3s represents the actual output torque value of the current motor at time t, 0<k2<0.5, t2<t≤t3, the value of b is consistent with the value of the actual output torque T2 of the motor in the previous cycle, when t=t3, the value of T3s is consistent with the torque command T1 issued by the vehicle controller VCU, among which, dt1=t1-0, dt3=t3-t2, and the torque adjustment time of the stage adjustment function of the third stage is dt3, dt=dt1+dt2+dt3;

[0045] Step 4: According to the stage adjustment function of the first stage, the actual output torque T2 of the motor in the previous cycle is adjusted to the preset transition torque Ts within the time range dt1;

[0046] Step 5: According to the stage adjustment function of the second stage, the actual output torque of the current motor is kept unchanged at Ts within the time range of dt2;

[0047] Step 6: According to the stage adjustment function of the third stage, the current actual output torque Ts of the motor is adjusted to the torque command T1 issued by the vehicle controller VCU within the time range dt3.

[0048] It should be noted that the preset transition torque Ts acts on the gear to rotate the gear to eliminate the inter-tooth clearance in the forward direction. It is necessary to overcome the static friction of the gear rotation and the dynamic friction after rotation. The static friction is related to the lubrication method, lubrication status, gear weight and material. The dynamic friction is related to the lubrication method, lubrication status and material. Ts is also related to the specific size of the inter-tooth clearance.

[0049] The lubrication mode can be obtained and represented by the coefficient Kl. The lubrication state and the size of the inter-tooth clearance are both characterized by the total operating time of the vehicle and expressed by the calculation formula of the correction value △Tc. △Tc is a preset constant value, which is a small fixed torque value. The calculation formula is: △Tc=(1+Kw*tw / t_life_max). t_life_max can be abbreviated as tmax, which represents the design life of the equipment. tw is the operating time of the equipment. Kw is the amplification factor. Kw>1, and the recommended value is [1.1,1.2].

[0050] The gear weight and material are characterized by the rated maximum working torque of the gear. The rated maximum working torque Tw is multiplied by the scaling factor Ks. The scaling factor Ks is less than 1 and is a preset constant value. The recommended value is Ks = 0.001 ~ 0.01. When the gear shaft and gear bearing are lubricated with oil, Kl = 1. When the gear shaft and gear bearing are lubricated with grease or connected through bearings, Kl = 1.05.

[0051] Ts=Tw*Ks*Kl*△Tc.

[0052] Example 3

[0053] An electronic device includes a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement any one of the motor torque zero-crossing response control strategies for electric vehicles as described above.

[0054] The embodiment described above is only a preferred solution of the present application and does not limit the present application in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A motor torque zero-crossing response control strategy for electric vehicles, characterized in that: The following steps are included: Step 1: The motor controller MCU obtains the actual output torque T2 of the motor in the previous cycle and the torque command T1 issued by the vehicle controller VCU; Step 2: The motor controller MCU calculates the absolute value DT of the torque difference between the torque command T1 issued by the vehicle controller VCU and the actual output torque T2 of the motor in the previous cycle; Step 3: Comparing the absolute value of the torque difference DT with a torque difference classification table to obtain a torque difference level and a torque adjustment function corresponding to the level. The torque adjustment function includes three different stage adjustment functions. The torque adjustment time dt and the absolute value of the adjusted torque difference Tc of the three different stage adjustment functions are adjusted according to the torque difference level. Step 4: According to the stage adjustment function of the first stage, the actual output torque T2 of the motor in the previous cycle is adjusted to the preset transition torque Ts within the time range of dt1. The preset transition torque Ts is used to slowly change the direction of the tooth side clearance and is related to the actual situation of the equipment. The preset transition torque Ts needs to be calibrated by the actual vehicle. At the same time, the absolute value of the preset transition torque Ts is controlled within 0-10 Nm. The preset transition torque Ts is related to the vehicle lubrication method, lubrication status, gear weight, inter-tooth clearance and gear material. The lubrication method can be obtained and represented by the coefficient Kl. The lubrication status and the size of the inter-tooth clearance are both represented by the total running time of the vehicle and represented by the calculation formula of the correction amount △Tc. The calculation formula is: △Tc=(1+Kw*tw / t_life_max), t_life_max can be abbreviated as tmax, which represents the design life of the equipment, tw is the running time of the equipment, Kw is the amplification coefficient, Kw>1, and the recommended value is [1.1,1.2]; The gear weight and material are characterized by the rated maximum working torque of the gear. The rated maximum working torque Tw is multiplied by the scaling factor Ks. The scaling factor Ks is less than 1 and is a preset constant value. The recommended value is Ks = 0.001 to 0.

01. When the gear shaft and gear bearing are lubricated with oil, Kl = 1. When the gear shaft and gear bearing are lubricated with lubricating grease or connected through bearings, Kl = 1.

05. Ts=Tw*Ks*Kl*△Tc; Step 5: In the second stage, the torque difference is adjusted to zero by the adjustment function, and the actual output torque of the current motor is kept unchanged at Ts within the time range dt2; Step 6: According to the stage adjustment function of the third stage, the current actual output torque Ts of the motor is adjusted to the torque command T1 issued by the vehicle controller VCU within the time range dt3; In step 3, the torque difference levels in the torque difference classification table are sorted in ascending order according to the torque difference level corresponding to the increasing absolute value of the torque difference. The absolute value of the torque difference corresponding to a higher level is greater than the absolute value of the torque difference corresponding to a lower level. The difference between the absolute values of the torque differences of adjacent levels gradually increases. When the absolute value DT of the torque difference does not uniquely correspond to the absolute value of the torque difference in the torque difference classification table, the higher level between the torque difference levels where the absolute value DT of the torque difference is located and the torque adjustment function corresponding to the higher level are used to perform torque adjustment. The torque adjustment function includes three different stage adjustment functions, wherein, as the torque difference level increases, the torque adjustment time dt1 and the absolute value of the adjusted torque difference Tc1 in the first stage first increase and then decrease; the torque adjustment time dt2 of the stage adjustment function in the second stage increases, and the absolute value of the torque difference adjusted by the adjustment function Tc2 is zero, and dt2 is controlled within 0.8-1.1s; the torque adjustment time dt3 of the third stage increases, and the absolute value of the adjusted torque difference Tc3 remains unchanged.

2. The motor torque zero-crossing response control strategy for electric vehicles according to claim 1, characterized in that: The stage adjustment function of the first stage is: T1s=k1t n +b, T1s represents the actual output torque value of the current motor at time t, t≤t1, 0<k1<3, the value of b is consistent with the value of the actual output torque T2 of the motor in the previous cycle, and t1 is the adjustment duration of the stage adjustment function of the first stage.

3. The motor torque zero-crossing response control strategy for electric vehicles according to claim 2, characterized in that: The stage adjustment function of the second stage is, T2s=k1t1 n +b, T2s represents the actual output torque value of the current motor at time t1, and T2s is consistent with the preset transition torque Ts value. The torque adjustment time of the stage adjustment function in the second stage is dt2.

4. The motor torque zero-crossing response control strategy for electric vehicles according to claim 3, characterized in that: The stage adjustment function of the third stage is T3s=k2t+b, where T3s represents the actual output torque value of the current motor at time t, 0<k2<0.5, t2<t≤t3, and the value of b is consistent with the value of the actual output torque T2 of the motor in the previous cycle. When t=t3, the value of T3s is consistent with the torque command T1 issued by the vehicle controller VCU.

5. An electronic device, characterized in that: The invention comprises a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the motor torque zero-crossing response control strategy for an electric vehicle according to any one of claims 1 to 4.

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