Method for limiting charging and discharging power of power battery

Abstract

The invention discloses a method for limiting charging and discharging power of a power battery. The method comprises the following steps of: acquiring working parameters of a power battery, working parameters of a driving motor and driving parameters of a whole vehicle in real time; determining the limit torque of the motor; determining output backup power when the power battery is discharged or input backup power when the power battery is charged according to the working parameters of the power battery; determining a motor capability limiting torque according to the working parameters of the driving motor; determining an expected required torque of a driver according to the whole vehicle driving parameters; comparing the output backup power with a backup power preset value or comparing the input backup power with the backup power preset value, and determining the actual demand torque of the driver according to the comparison result, the motor limit torque, the motor capability limit torque and the expected demand torque of the driver. According to the invention, the phenomenon that the required power of the power system is not matched with the capacity of the power battery can be avoided, and the phenomenon of long-time over-charging and over-discharging of the power battery in the use process can be avoided.

Description

technical field [0001] The invention belongs to the technical field of automobiles, and in particular relates to a method for limiting charging and discharging power of a power battery. Background technique [0002] During the actual charging and discharging process of the power battery, the current and power are determined by the load, and the power battery is in the process of passive charging and discharging. Because the efficiency of the driving motor is different under different working conditions, and the motor torque will have a certain deviation at different speeds, due to control deviation or motor torque deviation, it will cause the power battery to over-current or exceed the allowable power of the battery. If the battery capacity is exceeded for a long time, the battery will report current or power failure, resulting in power interruption of the vehicle. At the same time, the life of the power battery will be affected due to the battery being overcharged or overdi...

AI Technical Summary

Problems solved by technology

Since the efficiency of the drive motor is different under different working conditions, and the motor torque will have a certain deviation at different speeds, due to control deviation or motor torque deviation, it will cause the power battery to over-current or exceed the allowable power of the battery. If the battery capacity is exceeded for a long time, the battery will report current or power failure, resulting in power interruption of the vehicle. At the same time, the life of the power battery will be affected due to the battery being overcharged or overdischarged. In severe cases, it may cause safety problems of the power battery.

Therefore, it is necessary to detect the working status of the power battery, the driving motor and the driver's demand torque at all times, and limit the current and power of the battery to be within the allowable range of the battery during the actual charging and discharging process.