Motor torque control method and system for protecting battery
By obtaining vehicle parameters and adjusting the motor torque limit, the problem of motor torque control being unable to accurately protect the battery is solved, and real-time protection and life extension of the battery are achieved.
Patent Information
- Application Number
- CN202510839975.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-09-12
AI Technical Summary
In the existing technology, the motor torque control method cannot accurately protect the battery, resulting in battery overcharging and over-discharging, affecting battery life and safety.
By obtaining vehicle parameters, calculating the motor torque limit correction value, and adjusting the motor's maximum and minimum torque limits based on the vehicle's slope conditions, precise control of the motor can be achieved.
Real-time protection of the battery is achieved to avoid overcharging and over-discharging, extend battery life and reduce safety risks.
Smart Images
Figure CN120621074A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to a motor torque control method, and more particularly to a motor torque control method and system for protecting batteries, belonging to the technical field of battery protection. Background Art
[0002] The battery management system of an electric vehicle is a passive discharge device. The motor is the most important high-voltage driving component of the electric vehicle. Torque control directly affects the overcharging and over-discharging of the battery. In severe cases, it will cause battery failure and affect the battery life.
[0003] The current main battery charge and discharge capacity protection logic is based on battery capacity and takes into account the power consumption of accessories, which is used as a limit on motor power. This is then converted into the maximum and minimum torque limits of the motor according to the formula, thereby limiting the motor capacity and achieving battery protection.
[0004] Battery capacity is electrical power, and motor torque limit is used to calculate mechanical power. There is an efficiency conversion coefficient between the two. The efficiency table provided by the test bench is a basic reference value. There may be differences under actual working conditions, and it is impossible to accurately control battery protection.
[0005] When the motor power consumption is particularly large or changes particularly quickly, the method of limiting the motor torque by battery capacity cannot effectively protect the battery, and the problem of battery overcharge and over-discharge will still occur. Summary of the Invention
[0006] In view of this, the present application provides a motor torque control method and system for protecting the battery to solve or alleviate the technical problems existing in the prior art and at least provide a beneficial option.
[0007] The technical solution of an embodiment of the present application is implemented as follows: a motor torque control method for protecting a battery, comprising the following steps: obtaining vehicle parameters to obtain a motor torque limit correction value based on the vehicle parameters; calculating a motor maximum torque limit and a motor minimum torque limit based on the motor torque limit correction value; obtaining a vehicle rolling downhill condition based on the vehicle parameters and the current gear to adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill condition; and controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.
[0008] Further preferably, the vehicle parameters include at least the discharge power allowed by the battery pack, the charging power allowed by the battery pack, the battery pack voltage, the real-time power of the high-voltage accessories, the motor bus voltage, the motor bus current, the motor speed and the motor torque.
[0009] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters includes: obtaining the accessory power of the whole vehicle, and obtaining the maximum discharge power available to the motor based on the discharge power allowed by the battery pack and the accessory power of the whole vehicle, so as to obtain the maximum current available to the motor according to the maximum discharge power available to the motor and the battery pack voltage; and obtaining the maximum charging power available to the motor based on the charging power allowed by the battery pack and the accessory power of the whole vehicle, so as to obtain the minimum current available to the motor according to the maximum charging power available to the motor and the battery pack voltage.
[0010] It is further preferred that: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: obtaining the electric power to mechanical power efficiency based on the motor speed, motor torque, motor bus voltage and motor bus current; and obtaining the mechanical power to electric power efficiency based on the electric power to mechanical power efficiency.
[0011] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: when the motor drive is discharging, obtaining the motor drive discharge power according to the motor bus current and the maximum current available to the motor; and when the motor is brake-charged, obtaining the motor brake charging power according to the motor bus current and the minimum current available to the motor.
[0012] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: when the motor drive discharge power is greater than or equal to the preset ratio, obtaining the motor torque limit correction value based on the motor drive discharge power, the preset ratio and the set value; otherwise, the motor torque limit is not corrected; when the motor braking charging power is greater than or equal to the preset ratio, obtaining the motor torque limit correction value based on the motor braking charging power, the preset ratio and the set data; otherwise, the motor torque limit is not corrected; wherein, the preset ratio and the set value are determined according to the battery performance and the motor performance.
[0013] Further preferred: the calculation of the maximum torque limit of the motor and the minimum torque limit of the motor based on the motor torque limit correction value includes: obtaining the maximum torque limit of the motor according to the maximum discharge power available to the motor, the efficiency of converting electric power to mechanical power, the motor speed and the motor torque limit correction value; and obtaining the minimum torque limit of the motor according to the maximum charging power available to the motor, the efficiency of converting mechanical power to electric power, the motor speed and the motor torque limit correction value.
[0014] Further preferred: the obtaining of the vehicle rolling downhill condition based on the vehicle parameters and the current gear includes: obtaining the current gear; when the current gear is a forward gear and the motor speed is less than a preset negative value, determining that the current vehicle is in a vehicle rolling downhill state; when the current gear is a reverse gear and the motor speed is greater than a preset positive value, determining that the current vehicle is in a vehicle rolling downhill state; wherein, if the current vehicle is in a vehicle rolling downhill state or a vehicle rolling downhill state, determining that the vehicle rolling downhill condition of the current vehicle is a rolling downhill state, and setting the flag bit to the first flag bit; otherwise determining that the vehicle rolling downhill condition of the current vehicle is a normal state, and setting the flag bit to the second flag bit.
[0015] Further preferred: the adjusting the maximum torque limit and the minimum torque limit of the motor according to the vehicle rolling downhill condition includes: obtaining the current vehicle rolling downhill condition according to the flag position; wherein, if the current flag position is the second flag position, the maximum torque limit and the minimum torque limit of the motor are not adjusted; if the current flag position is the first flag position, the maximum torque limit and the minimum torque limit of the motor are adjusted based on the set parameters.
[0016] Based on the same concept, the present application also provides a motor torque control system for protecting the battery, including: an acquisition module for acquiring vehicle parameters to obtain a motor torque limit correction value based on the vehicle parameters; a calculation module for calculating the motor maximum torque limit and the motor minimum torque limit based on the motor torque limit correction value; an adjustment module for obtaining a vehicle rolling downhill condition based on the vehicle parameters and the current gear to adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill condition; and a control module for controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.
[0017] The embodiment of the present application adopts the above technical solution, which has the following advantages:
[0018] This application establishes a real-time algorithm for driving motor torque, which protects the power battery and avoids overcharging and over-discharging, which may lead to battery system failure, reduced lifespan, and even safety accidents.
[0019] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0021] Figure 1 This is a flow chart of the motor torque control method for protecting the battery described in this application.
[0022] Figure 2 This is a framework diagram of the motor torque control system for protecting the battery described in this application. DETAILED DESCRIPTION
[0023] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.
[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0025] like Figure 1 As shown, an embodiment of the present application provides a motor torque control method for protecting a battery, comprising the following steps: obtaining vehicle parameters to obtain a motor torque limit correction value based on the vehicle parameters; calculating a motor maximum torque limit and a motor minimum torque limit based on the motor torque limit correction value; obtaining a vehicle rolling downhill condition based on the vehicle parameters and the current gear to adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill condition; and controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.
[0026] Further preferred: the vehicle parameters include at least the discharge power BMSPwrDchg allowed for the battery pack, the charging power BMSPwrChg allowed for the battery pack, the battery pack voltage BMSVolt, the high-voltage accessory real-time power HvLoadPwr, the motor bus voltage Udc, the motor bus current Idc, the motor speed DCUrpm and the motor torque DCUtq.
[0027] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters includes: obtaining the accessory power of the whole vehicle, and obtaining the maximum discharge power available to the motor based on the discharge power allowed by the battery pack and the accessory power of the whole vehicle, so as to obtain the maximum current available to the motor according to the maximum discharge power available to the motor and the battery pack voltage; and obtaining the maximum charging power available to the motor based on the charging power allowed by the battery pack and the accessory power of the whole vehicle, so as to obtain the minimum current available to the motor according to the maximum charging power available to the motor and the battery pack voltage.
[0028] Among them, the maximum discharge power available to the motor is the discharge power allowed by the battery pack minus the power of the vehicle accessories, that is: DCUPwrmax = BMSPwrDchg-AccPw; the maximum charging power available to the motor is the charging power allowed by the battery pack minus the power of the vehicle accessories, that is: DCUPwrmin = BMSPwrChg-AccPwr.
[0029] It should be noted that since the discharge power is a positive value and the charging power is a negative value, DCUPwrmin is used here to represent the maximum charging power available to the motor.
[0030] Furthermore, the maximum current available to the motor is Idcmax=DCUPwrmax / BMSVolt, and the minimum current available to the motor is Idcmin=DCUPwrmin / BMSVolt.
[0031] It is further preferred that: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: obtaining the electric power to mechanical power efficiency based on the motor speed, motor torque, motor bus voltage and motor bus current; and obtaining the mechanical power to electric power efficiency based on the electric power to mechanical power efficiency.
[0032] The efficiency of converting electrical power to mechanical power, EffDchg, is calculated as follows: (DCUrpm*DCUtq / 9.55) / (Udc*Idc).
[0033] Mechanical power to electrical power efficiency EffChg = 1 / EffDchg.
[0034] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: when the motor drive is discharging, obtaining the motor drive discharge power according to the motor bus current and the maximum current available to the motor; and when the motor is brake-charged, obtaining the motor brake charging power according to the motor bus current and the minimum current available to the motor.
[0035] Among them, the motor torque limit correction value is calculated according to the ratio of the actual motor current to the maximum and minimum currents: when the motor is driving discharge, the motor driving discharge power Kdchg = Idc / Idcmax; when the motor is braking and charging, the motor braking charging power Kchg = Idc / Idcmin.
[0036] Further preferred: the obtaining of the motor torque limit correction value based on the vehicle parameters also includes: when the motor drive discharge power is greater than or equal to the preset ratio Kfac, obtaining the motor torque limit correction value based on the motor drive discharge power, the preset ratio and the set value; otherwise, the motor torque limit is not corrected; when the motor braking charging power is greater than or equal to the preset ratio Kfac, obtaining the motor torque limit correction value based on the motor braking charging power, the preset ratio and the set data; otherwise, the motor torque limit is not corrected; wherein, the preset ratio Kfac and the set value Kp are determined according to the battery performance and the motor performance.
[0037] The current ratio is calculated in real time. When the ratio is less than Kfac, the torque limit is not corrected, otherwise it is corrected.
[0038] When the motor is driven to discharge:
[0039] Motor torque limit correction value
[0040] When the motor is braking and charging:
[0041] Motor torque limit correction value
[0042] Further preferred: the calculation of the maximum torque limit of the motor and the minimum torque limit of the motor based on the motor torque limit correction value includes: obtaining the maximum torque limit of the motor according to the maximum discharge power available to the motor, the efficiency of converting electric power to mechanical power, the motor speed and the motor torque limit correction value; and obtaining the minimum torque limit of the motor according to the maximum charging power available to the motor, the efficiency of converting mechanical power to electric power, the motor speed and the motor torque limit correction value.
[0043] The maximum torque limit of the motor DCUtqmax = (DCUPwrmax*EffDchg*9.55 / DCUrpm) - ΔTq; the minimum torque limit of the motor DCUtqmin = (DCUPwrmin / EffChg / 9.55 / DCUrpm) + ΔTq.
[0044] Further preferred: the obtaining of the vehicle rolling downhill condition based on the vehicle parameters and the current gear position includes: obtaining the current gear position; when the current gear position DrvGear is the forward gear and the motor speed DCUrpm is less than the preset negative value nneg, determining that the current vehicle is in the vehicle rolling downhill state; when the current gear position DrvGear is the reverse gear and the motor speed DCUrpm is greater than the preset positive value npos, determining that the current vehicle is in the vehicle rolling downhill state; wherein, if the current vehicle is in the vehicle rolling downhill state or the vehicle rolling downhill state, determining that the vehicle rolling downhill condition of the current vehicle is the rolling downhill state, and setting the flag bit to the first flag bit bVehIvs=1; otherwise determining that the vehicle rolling downhill condition of the current vehicle is the normal state, and setting the flag bit to the second flag bit bVehIvs=0.
[0045] Further preferred: the adjusting the maximum torque limit and the minimum torque limit of the motor according to the vehicle rolling downhill condition includes: obtaining the current vehicle rolling downhill condition according to the flag position; wherein, if the current flag position is the second flag position, the maximum torque limit and the minimum torque limit of the motor are not adjusted; if the current flag position is the first flag position, the maximum torque limit and the minimum torque limit of the motor are adjusted based on the set parameters.
[0046] Among them, when bVehIvs=0, the maximum torque limit of the motor is DCUtqmax, and the minimum torque limit is DCUtqmin; when bVehIvs=1, the maximum torque limit of the motor is (-1)*DCUtqmin, and the minimum torque limit is (-1)*DCUtqmax.
[0047] Based on the same concept, Figure 2 As shown, the present application also provides a motor torque control system for protecting the battery, including: an acquisition module for acquiring vehicle parameters to obtain a motor torque limit correction value based on the vehicle parameters; a calculation module for calculating a motor maximum torque limit and a motor minimum torque limit based on the motor torque limit correction value; an adjustment module for obtaining a vehicle rolling downhill condition based on the vehicle parameters and the current gear to adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill condition; and a control module for controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.
[0048] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.
Claims
1. A motor torque control method for protecting a battery, characterized in that: The following steps are involved: Acquiring vehicle parameters to obtain a motor torque limit correction value based on the vehicle parameters; Calculating a maximum torque limit value of the motor and a minimum torque limit value of the motor based on the motor torque limit correction value; Obtaining a vehicle rolling downhill operating condition based on the vehicle parameters and the current gear position, so as to adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill operating condition; and controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.
2. The motor torque control method for protecting the battery according to claim 1, characterized in that: The vehicle parameters include at least the discharge power allowed by the battery pack, the charging power allowed by the battery pack, the battery pack voltage, the real-time power of the high-voltage accessories, the motor bus voltage, the motor bus current, the motor speed and the motor torque.
3. The motor torque control method for protecting the battery according to claim 2, characterized in that: The obtaining of a motor torque limit correction value based on the vehicle parameter includes: Obtaining the power of the entire vehicle accessories, and obtaining the maximum discharge power available to the motor based on the discharge power allowed by the battery pack and the power of the entire vehicle accessories, so as to obtain the maximum current available to the motor based on the maximum discharge power available to the motor and the battery pack voltage; Furthermore, the maximum charging power available to the motor is obtained based on the charging power allowed by the battery pack and the power of the vehicle accessories, so as to obtain the minimum current available to the motor according to the maximum charging power available to the motor and the battery pack voltage.
4. The motor torque control method for protecting the battery according to claim 3, characterized in that: The obtaining of the motor torque limit correction value based on the vehicle parameter further includes: Obtaining an electric power-to-mechanical power conversion efficiency based on the motor speed, motor torque, motor bus voltage, and motor bus current; And the mechanical power to electrical power efficiency is obtained according to the electrical power to mechanical power efficiency.
5. The motor torque control method for protecting the battery according to claim 4, characterized in that: The obtaining of the motor torque limit correction value based on the vehicle parameter further includes: When the motor is driven to discharge, the motor driving discharge power is obtained according to the motor bus current and the maximum current available to the motor; And when the motor is braked and charged, the motor braking charging power is obtained according to the motor bus current and the minimum current available to the motor.
6. The motor torque control method for protecting the battery according to claim 5, characterized in that: The obtaining of the motor torque limit correction value based on the vehicle parameter further includes: When the motor drive discharge power is greater than or equal to a preset ratio, a motor torque limit correction value is obtained based on the motor drive discharge power, the preset ratio and the set value; otherwise, the motor torque limit is not corrected; When the motor braking charging power is greater than or equal to the preset ratio, a motor torque limit correction value is obtained based on the motor braking charging power, the preset ratio and the set data; otherwise, the motor torque limit is not corrected; The preset ratio and the set value are determined according to the battery performance and the motor performance.
7. The motor torque control method for protecting the battery according to claim 6, characterized in that: The calculating the maximum torque limit value and the minimum torque limit value of the motor based on the motor torque limit correction value includes: Obtaining a maximum torque limit of the motor according to the maximum discharge power available for the motor, the efficiency of converting electric power to mechanical power, the motor speed, and the motor torque limit correction value; And the minimum torque limit of the motor is obtained according to the maximum charging power available to the motor, the mechanical power to electrical power efficiency, the motor speed and the motor torque limit correction value.
8. The motor torque control method for protecting the battery according to claim 7, characterized in that: The obtaining of the vehicle rolling downhill condition based on the vehicle parameters and the current gear position includes: Get the current gear; When the current gear is a forward gear and the motor speed is less than a preset negative value, it is determined that the current vehicle is in a backward sliding state; When the current gear is a reverse gear and the motor speed is greater than a preset positive value, it is determined that the current vehicle is in a forward sliding state; Among them, if the current vehicle is in a vehicle sliding backward state or a vehicle sliding forward state, it is determined that the vehicle sliding downhill condition of the current vehicle is a sliding downhill state, and the flag is set to the first flag; otherwise, it is determined that the vehicle sliding downhill condition of the current vehicle is a normal state, and the flag is set to the second flag.
9. The motor torque control method for protecting the battery according to claim 8, characterized in that: The adjusting the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill condition includes: Obtain the current vehicle sliding downhill condition according to the flag position; If the current flag is the second flag, the maximum torque limit and the motor minimum torque limit are not adjusted; If the current flag is the first flag, the maximum torque limit and the motor minimum torque limit are adjusted based on the set parameters.
10. A system using the motor torque control method for protecting a battery according to any one of claims 1 to 9, characterized in that: include: an acquisition module, configured to acquire vehicle parameters, so as to obtain a motor torque limit correction value based on the vehicle parameters; a calculation module, configured to calculate a maximum torque limit of the motor and a minimum torque limit of the motor based on the motor torque limit correction value; an adjustment module, configured to obtain a vehicle rolling downhill operating condition based on the vehicle parameters and the current gear position, and adjust the maximum torque limit and the motor minimum torque limit according to the vehicle rolling downhill operating condition; and a control module for controlling the motor according to the adjusted maximum torque limit and the motor minimum torque limit.