Vehicle driving motor torque limiting method and electronic equipment

Abstract

The invention discloses a vehicle driving motor torque limiting method and electronic equipment. The method comprises the steps of monitoring actual current of a driving motor; when the actual current is larger than or equal to the first current threshold value, the limiting torque percentage is generated according to the actual current, the limiting torque is calculated according to the limiting torque percentage, the limiting torque percentage linearly changes along with the actual current, and the limiting torque is output. According to the invention, a torque limiting system is preferentially carried out based on the current, and EPT overcurrent can be effectively protected from the change of the current as a fundamental factor. And meanwhile, the torque is linearly limited based on the change of the current, so that the overcurrent problem and the drivability jerking problem generated when the torque is limited can be fundamentally solved. And finally, since the torque limiting is directly carried out through the current in the INV, the execution speed is higher than that of the TCS by detecting the slip rate of the wheel end, and the torque can be limited more quickly.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle-related technologies, and in particular to a method for limiting the torque of a vehicle drive motor, an electronic device, a storage medium and a computer program product. Background Art

[0002] The control method commonly used in the existing permanent magnet synchronous motor is MTPA control, namely maximum torque control and weak magnetic control. This method is based on the previous calibration of different voltages, different speeds, and different torques on the bench to obtain the current direct axis current component (Id) and quadrature axis current component (Iq) map. Figure 1 As shown, during the actual driving process of the vehicle, based on the current throttle opening signal and brake signal, the vehicle controller (Vehicle Control Module) 1' outputs a torque output request including the VCM command torque to the drive motor controller (INV) 2'. The drive motor controller 2' outputs the command current that the current drive motor should output based on the current motor speed and the torque requested by the vehicle controller 1' by querying the previously calibrated current Id and Iq map table, thereby controlling the drive motor 4' to output torque according to the torque request of the vehicle controller 2'. The accuracy of the table lookup of this method depends on the three parameters of voltage, speed, and torque command.

[0003] Among them, the vehicle controller 1' includes a torque limiting module 11' and an output torque control module 12', wherein the torque limiting module 11' is used to receive the TCS required torque of the traction control system (Traction Control System) 4' (also known as the anti-skid system), and the output torque control module 12' combines the TCS required torque, throttle opening and motor speed to output the VCM command torque to the drive motor controller 2'.

[0004] The drive motor controller 2' comprises an input torque gradient filter module 21', an INV output torque calculation module 22', an anti-runaway protection module 23', a vector control module 24', a power module 25', and a motor speed calculation module 26', wherein the input torque gradient filter module 21' receives the VCM command torque, outputs the required torque to the torque calculation module 22' after gradient filtering according to the VCM command torque, and the torque calculation module 22' combines the required torque and the limit torque output by the anti-runaway protection module 23', calculates the output torque as the minimum value of the required torque and the limit torque, and then transmits the output torque to the vector control module 24', calculates the control current that should be output to the power module 25', so as to control the drive motor 4'. At the same time, the motor speed calculation module 26' calculates the motor speed according to the motor rotation angle output by the rotation angle resolver 41' (also known as the rotary transformer), and sends it to the anti-runaway protection module 23'.

[0005] The traction control system 3' comprises a slip ratio calculation module 31', a TCS torque calculation module 32' and a wheel speed sensor 33', wherein the slip ratio calculation module 31' obtains the wheel speed from the wheel speed sensor 33', calculates and outputs the slip ratio to the TCS torque calculation module 32', and the TCS torque calculation module 32' calculates the TCS required torque and outputs it to the vehicle controller 1'.

[0006] The existing methods have the following defects:

[0007] When the vehicle is accelerating at full throttle on a low-adhesion road or over a speed bump, the drive motor controller may cause the command current output by the table to exceed the limit due to the excessively fast speed change rate. For this reason, the prior art adds a runaway protection module 23' in the drive motor controller 2'. The runaway protection module 23' monitors the motor speed provided by the motor speed calculation module 26'. When the speed change rate exceeds a certain threshold, the torque is limited to reduce the limit torque. This method can prevent overcurrent faults from occurring. However, this control method is easily triggered by mistake during driving, resulting in an abnormal driving experience.

[0008] In addition, the working logic of the traction control system of the existing vehicle is as follows:

[0009] The traction control system 3' detects that the wheel end slip rate deviation is too large -> feedback is given to the vehicle controller 1'' to limit the torque request -> the drive motor controller 2' needs to slowly execute the torque reduction after receiving the torque request. The whole process takes tens of milliseconds.

[0010] Therefore, it takes tens of milliseconds for the TCS to detect slip and for the drive controller to execute torque limitation, which is a relatively slow execution speed. In addition, the TCS may be turned off by the customer on the actual vehicle, resulting in a lack of protection for the entire vehicle when the TCS is turned off. To this end, the prior art introduces a torque limitation strategy based on the speed change rate by canceling the switch that turns off the TCS or forcing it to turn on when slip is detected when the TCS is turned off. However, even if the TCS is turned on, its execution speed is still too slow. Summary of the invention

[0011] Based on this, it is necessary to provide a vehicle drive motor torque limiting method, electronic device, storage medium and computer program product to address the technical problems that the torque limiting control method in the prior art is easily triggered by mistake, causing abnormal driving experience, and the slip detection execution speed through TCS is slow on the other hand.

[0012] The present invention provides a method for limiting the torque of a vehicle drive motor, comprising:

[0013] Monitor the actual current of the drive motor;

[0014] When the actual current is greater than or equal to a first current threshold, a limiting torque percentage is generated according to the actual current, and a limiting torque is calculated according to the limiting torque percentage, wherein the limiting torque percentage changes linearly with the actual current;

[0015] The limit torque is output.

[0016] Further, when the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and the limiting torque percentage changes linearly with the actual current, including:

[0017] When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage. When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, the limiting torque percentage changes linearly with the actual current, and the second current threshold is greater than the first current threshold.

[0018] Furthermore, the limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and when the actual current is greater than or equal to a first current threshold and less than or equal to a second current threshold, the limiting torque percentage changes linearly with the actual current, including:

[0019] Calculate the limiting torque percentage as Wherein, K is the limiting torque percentage, K1 is the first torque percentage, Iu is the actual current, Ioc1 is the first current threshold, and Ioc2 is the second current threshold;

[0020] The calculated limit torque is the maximum torque of the drive motor at the current motor speed multiplied by the limit torque percentage.

[0021] Furthermore, when the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and the limiting torque percentage changes linearly with the actual current, and further includes:

[0022] When the actual current is greater than the second current threshold, the limit torque is set to a first torque value.

[0023] Furthermore, the first torque value is the first torque percentage multiplied by the maximum torque of the driving motor at the current motor speed.

[0024] Further, when the actual current is greater than the second current threshold, setting the limit torque to a first torque value includes:

[0025] When the actual current is greater than the second current threshold, the limiting torque is set to a preset first torque value, and the motor speed change rate is detected at the same time;

[0026] When the actual current is greater than the second current threshold and the motor speed change rate is greater than the change rate threshold, the limiting torque is set to a second torque value, and the second torque value is less than the first torque value.

[0027] Furthermore, the second torque value is 0.

[0028] The present invention provides an electronic device, comprising:

[0029] at least one processor; and,

[0030] a memory communicatively connected to at least one of the processors; wherein,

[0031] The memory stores instructions that can be executed by at least one of the processors. The instructions are executed by at least one of the processors to enable the at least one of the processors to perform the vehicle drive motor torque limiting method as described above.

[0032] The present invention provides a storage medium, wherein the storage medium stores computer instructions. When a computer executes the computer instructions, the storage medium is used to execute all steps of the vehicle drive motor torque limiting method as described above.

[0033] The present invention provides a computer program product, comprising a computer program / instruction, which implements the vehicle drive motor torque limiting method as described above when the computer program / instruction is executed by a processor.

[0034] The present invention monitors the actual current of the driving motor, generates a limiting torque that changes linearly with the actual current according to the actual current, and controls the output torque of the driving motor to be less than or equal to the limiting torque. Therefore, the present invention preferentially limits the torque based on the current, and can effectively protect the electric powertrain (EPT) from overcurrent from the fundamental factor of current change. At the same time, linearly limiting the torque based on the change of current can fundamentally solve the overcurrent problem and the driving frustration problem caused by limiting the torque. Finally, since the torque limit is directly performed by current in INV, the execution speed is faster than the TCS method of detecting the wheel end slip rate, and the torque can be limited faster. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a vehicle drive motor torque limiting system in the prior art;

[0036] Figure 2This is a working diagram of a method for limiting the torque of a vehicle drive motor according to an embodiment of the present invention;

[0037] Figure 3 This is a working flow chart of a method for limiting torque of a vehicle drive motor according to another embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a vehicle drive motor torque limiting system according to a preferred embodiment of the present invention;

[0039] Figure 5 A working diagram of a method for limiting the torque of a vehicle drive motor according to a preferred embodiment of the present invention;

[0040] Figure 6 A schematic diagram showing the change of limiting torque with current in the best embodiment of the present invention;

[0041] Figure 7 It is a schematic diagram of the change of the limiting torque with the speed change rate in the prior art;

[0042] Figure 8 A schematic diagram of the change of the limiting torque with the speed change rate in the prior art of speed bumps;

[0043] Fig. 9 It is a schematic diagram showing the variation of the limiting torque with the current in the best embodiment of the present invention when passing over a speed bump;

[0044] Fig.10 It is a schematic diagram of the change rate of the limiting torque of the existing technology on the road surface with too low μ as the speed changes;

[0045] Fig.11 It is a schematic diagram showing the variation of the limiting torque with the current of the best embodiment of the present invention for a road surface with too low μ;

[0046] Fig.12 It is a schematic diagram of the change rate of the limiting torque with the speed change of the prior art for normal 0-100 acceleration;

[0047] Fig.13 It is a schematic diagram of the change of the limiting torque with the current of the best embodiment of the present invention during normal 0-100 acceleration;

[0048] Fig.14 It is a parameter calibration flow chart of the best embodiment of the present invention;

[0049] Fig.15 The figure is a schematic diagram of the hardware structure of an electronic device of the present invention. DETAILED DESCRIPTION

[0050] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. The same components are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0051] like Figure 2 The figure shows a working flow chart of a method for limiting torque of a vehicle drive motor according to an embodiment of the present invention, comprising:

[0052] Step S201, monitoring the actual current of the driving motor;

[0053] Step S202, when the actual current is greater than or equal to the first current threshold, generating a limiting torque percentage according to the actual current, and calculating the limiting torque according to the limiting torque percentage, wherein the limiting torque percentage changes linearly with the actual current;

[0054] Step S203: outputting the limit torque.

[0055] Specifically, the present invention can be applied to electronic devices with processing capabilities, such as a controller of a vehicle, such as an electronic control unit (ECU) of a vehicle. Preferably, a method for limiting the torque of a vehicle drive motor of the present invention is applied to a drive motor controller of the drive motor.

[0056] like Figure 4 The figure shows a schematic diagram of a vehicle drive motor torque control system according to a preferred embodiment of the present invention, which includes: a vehicle controller 1 , a drive motor controller 2 and a traction control system 3 .

[0057] The vehicle controller 1 includes a torque limiting module 11 and an output torque control module 12, wherein the torque limiting module 11 is used to receive the TCS required torque of the traction control system (Traction Control System) 3 (also known as the anti-skid system), and the output torque control module 12 combines the TCS required torque, throttle opening and motor speed to output the VCM command torque to the drive motor controller 2.

[0058] The drive motor controller 2 includes an input torque gradient filter module 21, an INV output torque calculation module 22, a vehicle drive motor torque limit module 23, a vector control module 24, a power module 25, and a motor speed calculation module 26, wherein the input torque gradient filter module 21 receives the VCM command torque, performs gradient filtering according to the VCM command torque, and outputs the required torque to the torque calculation module 22, and the torque calculation module 22 combines the required torque and the limited torque output by the vehicle drive motor torque limit module 23, calculates the output torque as the minimum value of the required torque and the limited torque, and then transmits the output torque to the vector control module 24, calculates the control current that should be output to the power module 25, so as to control the drive motor 4. At the same time, the motor speed calculation module 26 calculates the motor speed according to the motor rotary angle output by the rotary angle resolver 41 (also known as the rotary transformer), and sends it to the vehicle drive motor torque limit module 23.

[0059] The traction control system 3 includes a slip ratio calculation module 31, a TCS torque calculation module 32 and a wheel speed sensor 33, wherein the slip ratio calculation module 31 obtains the wheel speed from the wheel speed sensor 33, calculates and outputs the slip ratio to the TCS torque calculation module 32, and the TCS torque calculation module 32 calculates the TCS required torque and outputs it to the vehicle controller 1.

[0060] The vehicle drive motor torque limiting module 23 in the drive motor controller 2 executes a vehicle drive motor torque limiting method of the present invention to output a limited torque. Meanwhile, the vehicle drive motor torque limiting module 23 also outputs the limited torque to the vehicle controller 1 to notify the vehicle controller 1.

[0061] Specifically, step S201 is first performed to monitor the actual current of the drive motor.

[0062] Specifically, the power module 25 may provide three-phase current to the vehicle drive motor torque limiting module 23 , thereby enabling monitoring of the actual current of the drive motor.

[0063] In some embodiments, the actual current is the actual value of the three-phase current on the motor side.

[0064] Then, when it is monitored that the actual current is greater than the first current threshold, in step S202, when the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and a limiting torque is calculated according to the limiting torque percentage, and the limiting torque percentage changes linearly with the actual current.

[0065] Specifically, when the actual current is less than the first current threshold Ioc1, the drive motor controller hardware will not have overcurrent, no protection is required, and therefore no torque limitation is performed. The first current threshold Ioc1 is the carrying capacity current of the IGBT, and no protection is required below this current. The Ioc1 is the current boundary of the IGBT.

[0066] When the actual current is greater than the first current threshold Ioc1, the drive motor controller hardware is at risk of overcurrent. Therefore, at this time, linear torque limitation through current can not only effectively prevent overcurrent but also reduce the impact of driving performance during torque limitation. It can cope with most working conditions such as speed bumps and roads with low adhesion (referred to as low μ). Since the torque is not smooth due to a sudden drop in torque, the torque is limited to follow the linear change of the actual current to avoid the frustration caused by non-linear changes in torque.

[0067] Finally, step S203 is executed to output the limit torque.

[0068] Among them, the limited torque is output to the torque calculation module 22 of the drive motor controller 2. The torque calculation module 22 receives the required torque provided by the vehicle controller 1 and the limited torque output by the vehicle drive motor torque limiting module 23 after executing the present invention. After taking the minimum value of the required torque and the limited torque, the output torque is obtained. Then, the control current is determined according to the output torque to control the drive motor. At the same time, the limited torque can also be output to the vehicle controller 1 to notify the vehicle controller 1.

[0069] The present invention monitors the actual current of the drive motor, generates a limiting torque that changes linearly with the actual current according to the actual current, and controls the output torque of the drive motor to be less than or equal to the limiting torque. Therefore, the present invention prioritizes torque limitation based on current, and can effectively protect EPT overcurrent from the fundamental factor of current change. At the same time, linearly limiting torque based on current changes can fundamentally solve the overcurrent problem and the driving frustration problem caused by limiting torque. Finally, since TCS executes the torque limiting logic: TCS->VCM->INV, the torque limit is directly performed through current in INV, which is faster than TCS detecting the wheel end slip rate, and the torque can be limited faster.

[0070] like Figure 3 The flowchart of a method for limiting the torque of a vehicle drive motor in another embodiment of the present invention is shown, comprising:

[0071] Step S301, monitoring the actual current of the driving motor.

[0072] Step S302, when the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, generate a limiting torque percentage according to the actual current, and calculate the limiting torque according to the limiting torque percentage, when the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, the limiting torque percentage changes linearly with the actual current, and the second current threshold is greater than the first current threshold.

[0073] In one embodiment, the limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and when the actual current is greater than or equal to a first current threshold and less than or equal to a second current threshold, the limiting torque percentage changes linearly with the actual current, including:

[0074] Calculate the limiting torque percentage as Wherein, K is the limiting torque percentage, K1 is the first torque percentage, Iu is the actual current, Ioc1 is the first current threshold, and Ioc2 is the second current threshold;

[0075] The calculated limit torque is the maximum torque of the drive motor at the current motor speed multiplied by the limit torque percentage.

[0076] In one embodiment, when the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and the limiting torque percentage changes linearly with the actual current, and further includes:

[0077] When the actual current is greater than the second current threshold, the limit torque is set to a first torque value.

[0078] In one embodiment, the first torque value is the first torque percentage multiplied by the maximum torque of the driving motor at the current motor speed.

[0079] In one embodiment, when the actual current is greater than the second current threshold, setting the limit torque to the first torque value includes:

[0080] When the actual current is greater than the second current threshold, the limiting torque is set to a preset first torque value, and the motor speed change rate is detected at the same time;

[0081] When the actual current is greater than the second current threshold and the motor speed change rate is greater than the change rate threshold, the limiting torque is set to a second torque value, and the second torque value is less than the first torque value.

[0082] In one embodiment, the second torque value is 0.

[0083] Step S303: outputting the limit torque.

[0084] Specifically, step S301 is first performed to monitor the actual current of the drive motor.

[0085] Specifically, the actual current (three-phase current) and the speed change rate of the driving motor are still calculated in real time. The actual current can be obtained from the power module 25, and the motor speed change rate can be obtained from the motor speed calculation module 26, and the difference between the motor speeds of two adjacent cycles is calculated and divided by the cycle length to obtain the motor speed change rate.

[0086] Then, when the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, step S302 is executed. When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage. When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, the limiting torque percentage changes linearly with the actual current, and the second current threshold is greater than the first current threshold.

[0087] Specifically, when the actual current is less than the first current threshold Ioc1, the drive motor controller hardware will not have overcurrent, no protection is required, and no torque limitation is performed.

[0088] When the actual current is between the first current threshold Ioc1 and the second current threshold Ioc2, the drive motor controller hardware has an overcurrent risk. At this time, linear torque limitation is performed through current, which can effectively prevent overcurrent and reduce the driving impact during torque limitation. It can cope with most working conditions such as speed bumps and low μ roads.

[0089] In one embodiment, the limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and when the actual current is greater than or equal to a first current threshold and less than or equal to a second current threshold, the limiting torque percentage changes linearly with the actual current, including:

[0090] Calculate the limiting torque percentage as Wherein, K is the limiting torque percentage, K1 is the first torque percentage, Iu is the actual current, Ioc1 is the first current threshold, and Ioc2 is the second current threshold;

[0091] The calculated limit torque is the maximum torque of the drive motor at the current motor speed multiplied by the limit torque percentage.

[0092] In some embodiments, the calculation of the limiting torque is the maximum torque of the drive motor at the current motor speed multiplied by the limiting torque percentage, including: calculating the limiting torque as the maximum torque of the external characteristic at the current speed × the limiting torque percentage. For example, if the current speed is 8000rpm and the maximum capacity before the protection is triggered is 300Nm, then after the limit is triggered, the torque is 300×percentage.

[0093] Specifically, Figure 6 The figure shows a schematic diagram of the linear change of the limit torque percentage with the current. When the actual current is less than Ioc1, no torque limitation is performed, and the output limit torque percentage is 100%. When the actual current is within the range of (Ioc1, Ioc2], the output limit torque changes linearly.

[0094] The existing technology based on the speed change rate control cannot achieve true linear limitation, because the speed change rate itself is not linear. For example, the speed change rate is 20000rpm / s at the current moment, and the speed change rate is 30000rpm / s at the next moment. The relationship between the speed change rate and the torque change is not a strict linear relationship. In addition, in order to better prevent overcurrent based on the speed change rate control, it is also necessary to follow Figure 8 The A-line logic limits torque as linearly as possible, so the speed change rate N1 threshold must be very low to ensure faster protection and overcurrent protection. If the N1 threshold is relatively low, it is more likely to be falsely triggered during the 0-100 acceleration process.

[0095] However, in this embodiment, the torque is controlled based on the change of current, and the relationship between current and torque is more linear.

[0096] The magnetic flux equation is:

[0097]

[0098] Among them, i d 、i q are the direct-axis and quadrature-axis currents, L d , L q are the direct-axis and quadrature-axis inductances, are the direct-axis and quadrature-axis flux linkages, respectively. For permanent magnet chain.

[0099] The torque equation of permanent magnet synchronous motor is:

[0100]

[0101] From the above torque calculation formula, it can be seen that the relationship between torque and current is more linear, and the torque lookup process is also based on linear lookup. This embodiment is optimized for different scenarios of current limitation and speed limitation, and current detection protection is performed in conventional scenarios. Ensure better protection of hardware while reducing the impact of side effects. At the same time, when the current limitation fails, add the last line of defense based on the speed change rate. The size of the speed change rate needs to be calibrated based on the actual vehicle.

[0102] Table 1 Comparison of limiting torque of this embodiment and prior art when passing over speed bumps

[0103]

[0104]

[0105] Table 2 Comparison of limiting torque of the present embodiment and the prior art on low μ road surfaces

[0106]

[0107] Table 3 Normal 0-100 acceleration Limiting torque comparison between this embodiment and the prior art

[0108]

[0109]

[0110] In one embodiment, when the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage, and the limiting torque percentage changes linearly with the actual current, and further includes:

[0111] When the actual current is greater than the second current threshold, the limit torque is set to a first torque value.

[0112] Specifically, Figure 6 As shown, when the actual current is greater than the second current threshold Ioc2, the limited torque percentage is the first torque percentage. Then the first torque value is the first torque percentage multiplied by the maximum torque of the driving motor at the current motor speed.

[0113] In one embodiment, the first torque value is the first torque percentage multiplied by the maximum torque of the driving motor at the current motor speed.

[0114] like Figure 6 As shown, the first torque percentage is K1.

[0115] As an example, when the driver is at full throttle and the torque output is 100% (200Nm), when the current is detected to be between Ioc1 and Ioc2, such as I1, the torque command will be updated as: Execute, at this time the torque will be limited to K × multiplied by the maximum torque of the drive motor at the current motor speed, and the torque decrease from 200Nm->K × multiplied by the maximum torque of the drive motor at the current motor speed will decrease linearly according to a certain gradient. K1 is the calibration quantity, the torque decrease gradient is the calibration quantity, and Ioc1 and Ioc2 are calibration quantities, which are determined by calibration for the actual vehicle model.

[0116] Table 4 Limiting torque percentage

[0117]

[0118]

[0119] Toc is the detection time after the current exceeds the specified threshold. It does not limit the torque immediately after exceeding the threshold, but it is triggered only when it exceeds the corresponding threshold and lasts longer than the time threshold T1. This T1 can also be calibrated.

[0120] like Fig.14 The parameter calibration flow chart of the best embodiment of the present invention is shown, including:

[0121] Step S1401, debugging software preparation;

[0122] Step S1402, investigating the extreme working conditions of the vehicle;

[0123] Step S1403, preliminary setting of software test strategy parameters;

[0124] Step S1404, using the software for making the method for limiting the torque of the vehicle drive motor of this embodiment;

[0125] Step S1405, software verification under extreme working conditions, if failed (NG), adjust parameters and execute step S1404, if passed (OK), execute step S1406;

[0126] Step S1406, negative effect verification, if NG, adjust parameters and execute step S1404, if OK, end.

[0127] In some embodiments, the method further includes: controlling the output torque to linearly decrease to the limit torque.

[0128] In some embodiments, it also includes: canceling the insulated-gate bipolar transistor (IGBT) hardware over-current threshold protection of the drive motor controller.

[0129] Specifically, the control method based on current detection to limit torque requires canceling the IGBT hardware overcurrent threshold protection. Canceling the IGBT hardware overcurrent threshold protection requires hardware evaluation and selecting IGBTs that do not require hardware overcurrent threshold protection.

[0130] Take the vehicle model as an example: cancel the IGBT hardware overcurrent fault, conduct full-scenario testing on the extreme operating conditions of the actual vehicle, and find out the limit current of the vehicle. Considering the protection margin and the high-current operating conditions of the module at high temperature, it is determined that canceling the IGBT hardware overcurrent fault will not trigger desaturation, the voltage spike is also within the module withstand voltage range, and multiple cycle tests have been completed. Therefore, it can be determined that the vehicle model can meet the needs and does not need an IGBT with hardware overcurrent threshold protection.

[0131] In one embodiment, when the actual current is greater than the second current threshold, setting the limit torque to the first torque value includes:

[0132] When the actual current is greater than the second current threshold, the limiting torque is set to a preset first torque value, and the motor speed change rate is detected at the same time;

[0133] When the actual current is greater than the second current threshold and the motor speed change rate is greater than the change rate threshold, the limiting torque is set to a second torque value, and the second torque value is less than the first torque value.

[0134] Specifically, when the current threshold is continuously higher than Ioc2, it means that the first torque value limited at this time cannot curb the current speed increase. Therefore, the motor speed change rate is detected, and when the motor speed change rate is higher than a certain change rate threshold, the second torque value protection is triggered. This can supplement the current protection deficiency in rare working conditions, such as when the current sensor fails and the first torque value still runs away.

[0135] More specifically, if the speed change rate is still very large after the torque limit has been implemented based on the current change, it means that the torque limit caused by the current change is not enough to prevent the vehicle from running away. At this time, the torque limit based on the speed change rate can be introduced to stop the vehicle urgently and protect the vehicle and EPT hardware from damage. Because the linear torque limit causes the torque to be reduced slowly, there is no time to protect the EPT. In order to perform the protection faster, the torque is quickly reduced according to the motor speed change rate.

[0136] In one embodiment, the second torque value is 0.

[0137] Specifically, when the current threshold is continuously higher than Ioc2, it indicates that the first torque value limited at this time cannot curb the speed increase in the current situation. Therefore, the motor speed change rate is detected. When the motor speed change rate is higher than a certain change rate threshold, 0% torque protection is triggered.

[0138] Finally, step S303 is executed to output the limit torque.

[0139] Specifically, we can use Figure 3 The vehicle drive motor torque limiting module 23 in the drive motor controller 2 executes a vehicle drive motor torque limiting method of this embodiment to output a limited torque. At the same time, the vehicle drive motor torque limiting module 23 also outputs the limited torque to the vehicle controller 1 to notify the vehicle controller 1.

[0140] This embodiment preferentially limits torque based on current, which can effectively protect EPT from overcurrent based on the fundamental factor current change. Linearly limiting torque based on current change can fundamentally solve the overcurrent problem and the driving frustration problem caused by limiting torque. If the speed change rate still has a large value after the torque limit has been performed based on the current change, it means that the torque limit caused by the current change is not enough to prevent the vehicle from running away. At this time, the torque limit of the speed change rate is introduced to stop the vehicle in an emergency and protect the vehicle and EPT hardware from damage.

[0141] like Figure 5 The flowchart of the vehicle drive motor torque limiting method according to the best embodiment of the present invention is shown, comprising:

[0142] Step S501, real-time sampling of three-phase current;

[0143] Among them, the three-phase current and speed change rate are still calculated in real time.

[0144] Step S502, when the current value is less than Ioc1, the INV hardware will not have overcurrent, no protection is required, no torque limitation is performed, and step S505 is executed;

[0145] Step S503, when the current value is between Ioc1 and Ioc2, there is an overcurrent risk in the INV hardware, and the linear torque is limited by the current, such as Figure 6 As shown, it can effectively prevent overcurrent and reduce the impact of driving when torque is limited. (It can cope with most working conditions such as speed bumps and low μ roads)

[0146] Step S504: When the current value is continuously higher than Ioc2, it indicates that the first torque value limited at this time cannot curb the increase in the current speed. Figure 7As shown, when the speed change rate is higher than a certain threshold, 0% torque protection is triggered. (In rare working conditions, it is used to supplement the insufficient current protection, such as the current sensor failure, and the car still runs away at the first torque value).

[0147] Step S505: EPT currently outputs maximum torque and EPT maximum capacity.

[0148] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0149] like Fig.14 The figure shows a hardware structure diagram of an electronic device of the present invention, including:

[0150] at least one processor 1401; and,

[0151] A memory 1402 is communicatively connected to at least one of the processors 1401; wherein:

[0152] The memory 1402 stores instructions that can be executed by at least one of the processors. The instructions are executed by at least one of the processors to enable the at least one of the processors to execute the vehicle drive motor torque limiting method as described above.

[0153] Fig.15 A processor 1501 is taken as an example.

[0154] The electronic device is preferably a driving motor controller. The electronic device may further include: an input device 1503 and a display device 1504 .

[0155] The processor 1501, the memory 1502, the input device 1503 and the display device 1504 may be connected via a bus or other means, and the figure takes the connection via a bus as an example.

[0156] The memory 1502 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as program instructions / modules corresponding to the vehicle drive motor torque limitation method in the embodiment of the present application, for example, Figure 2 , Figure 3 The processor 1501 executes various functional applications and data processing by running the non-volatile software programs, instructions and modules stored in the memory 1502, that is, the vehicle drive motor torque limiting method in the above embodiment is implemented.

[0157] The memory 1502 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required by at least one function; the data storage area may store data created according to the use of the vehicle drive motor torque limiting method, etc. In addition, the memory 1502 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 1502 may optionally include a memory remotely arranged relative to the processor 1501, and these remote memories may be connected to a device for executing the vehicle drive motor torque limiting method via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0158] The input device 1503 may receive a user click input, and generate a signal input related to the user setting and function control of the vehicle drive motor torque limiting method. The display device 1504 may include a display device such as a display screen.

[0159] The one or more modules are stored in the memory 1502 , and when executed by the one or more processors 1501 , the vehicle drive motor torque limiting method in any of the above method embodiments is executed.

[0160] The present invention monitors the actual current of the driving motor, generates a limiting torque that changes linearly with the actual current according to the actual current, and controls the output torque of the driving motor to be less than or equal to the limiting torque. Therefore, the present invention preferentially limits the torque based on the current, and can effectively protect the EPT from overcurrent from the fundamental factor of current change. At the same time, linearly limiting the torque based on the change of current can fundamentally solve the overcurrent problem and the driving frustration problem caused by limiting the torque. Finally, since the torque limit is directly performed by current in INV, it is executed faster than TCS by detecting the wheel end slip rate, and the torque can be limited faster.

[0161] An embodiment of the present invention provides a storage medium, wherein the storage medium stores computer instructions. When a computer executes the computer instructions, the storage medium is used to execute all steps of the vehicle drive motor torque limiting method as described above.

[0162] In the context of the present disclosure, a storage medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or apparatus. The storage medium may be a machine-readable signal medium or a machine-readable storage medium. Alternatively, the storage medium may be a non-temporary computer-readable storage medium, for example, a non-temporary computer-readable storage medium may be a ROM, a random access memory (Random Access Memory, RAM), a compact disc read-only memory (Compact Disc ROM, CD-ROM), a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0163] An embodiment of the present invention provides a computer program product, including a computer program / instruction, which implements the vehicle drive motor torque limiting method as described above when executed by a processor.

[0164] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for limiting the torque of a vehicle drive motor, characterized in that: include: Monitor the actual current of the drive motor; When the actual current is greater than or equal to a first current threshold, a limiting torque percentage is generated according to the actual current, and a limiting torque is calculated according to the limiting torque percentage, wherein the limiting torque percentage changes linearly with the actual current; The limit torque is output.

2. The method for limiting the torque of a vehicle drive motor according to claim 1, characterized in that: When the actual current is greater than or equal to the first current threshold, generating a limiting torque percentage according to the actual current, and calculating the limiting torque according to the limiting torque percentage, wherein the limiting torque percentage changes linearly with the actual current, comprises: When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, a limiting torque percentage is generated according to the actual current, and the limiting torque is calculated according to the limiting torque percentage. When the actual current is greater than or equal to the first current threshold and less than or equal to the second current threshold, the limiting torque percentage changes linearly with the actual current, and the second current threshold is greater than the first current threshold.

3. The method for limiting the torque of a vehicle drive motor according to claim 2, characterized in that: The generating of the limiting torque percentage according to the actual current and calculating the limiting torque according to the limiting torque percentage, wherein when the actual current is greater than or equal to a first current threshold and less than or equal to a second current threshold, the limiting torque percentage changes linearly with the actual current, comprises: Calculate the limiting torque percentage as Wherein, K is the limiting torque percentage, K1 is the first torque percentage, Iu is the actual current, Ioc1 is the first current threshold, and Ioc2 is the second current threshold; The calculated limit torque is the maximum torque of the drive motor at the current motor speed multiplied by the limit torque percentage.

4. The method for limiting the torque of a vehicle drive motor according to claim 2, characterized in that: When the actual current is greater than or equal to the first current threshold, a limiting torque percentage is generated according to the actual current, and a limiting torque is calculated according to the limiting torque percentage, wherein the limiting torque percentage changes linearly with the actual current, and further comprises: When the actual current is greater than the second current threshold, the limit torque is set to a first torque value.

5. The method for limiting the torque of a vehicle drive motor according to claim 4, characterized in that: The first torque value is the first torque percentage multiplied by the maximum torque of the driving motor at the current motor speed.

6. The method for limiting the torque of a vehicle drive motor according to claim 4, characterized in that: When the actual current is greater than the second current threshold, setting the limit torque to the first torque value includes: When the actual current is greater than the second current threshold, the limiting torque is set to a preset first torque value, and the motor speed change rate is detected at the same time; When the actual current is greater than the second current threshold and the motor speed change rate is greater than the change rate threshold, the limiting torque is set to a second torque value, and the second torque value is less than the first torque value.

7. The method for limiting the torque of a vehicle drive motor according to claim 6, characterized in that: The second torque value is 0.

8. An electronic device, characterized in that: include: at least one processor; and a memory communicatively connected to at least one of the processors; wherein, The memory stores instructions that can be executed by at least one of the processors, and the instructions are executed by at least one of the processors to enable at least one of the processors to execute the vehicle drive motor torque limiting method according to any one of claims 1 to 7.

9. A storage medium, characterized in that: The storage medium stores computer instructions, and when a computer executes the computer instructions, it is used to execute all steps of the vehicle drive motor torque limitation method as described in any one of claims 1 to 7.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the vehicle drive motor torque limiting method as claimed in any one of claims 1 to 7 is implemented.

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