Model inverse dynamic algorithm for extreme power of power battery pack

Abstract

The invention discloses a model inverse dynamic algorithm for the extreme power of a power battery pack, and aims to avoid the influence of the state of charge (SOC) accuracy of a battery on an extreme power estimated value due to calculation of the electrodynamic potential of the battery through a mathematical model. The model inverse dynamic algorithm comprises the following steps: establishing a polarization voltage model of a single battery and a terminal voltage model of the single battery by adopting a Thevenin equivalent circuit; computing the direct-current resistance R, polarization parameter Rp and tau of the battery according to an HPPC (Hybrid Pulse Power Characterization) experiment, and establishing a corresponding relation through the SOC and a temperature; computing current EMF(t) by using a current sampled voltage value U(t) and current I(t); computing a polarization voltage Up(t+dt) after pulse time according to Up(t); calculating extreme current according to EMF(t) and Up(t+dt); comparing the extreme current with a system design required value Imax, and selecting lower current for calculating a voltage value U(t+dt) after the pulse time; and computing extreme power and charging extreme power.

Description

technical field [0001] The invention relates to a power battery, in particular to a model back-calculation dynamic algorithm for limiting power of a power battery pack. Background technique [0002] The power battery is the power source of the electric vehicle. During the operation of the vehicle, the power of the battery shows strong dynamic characteristics with the driving conditions and the driver's operation. Accurately evaluate the charging and discharging power limit capabilities of the power battery in different states of charge to achieve the optimal match between the battery pack and the vehicle's dynamic performance, meet the vehicle's acceleration and climbing performance, and fully utilize the regenerative braking energy recovery of the motor function, and at the same time, it has guiding value for avoiding overcharging and overdischarging and prolonging the service life of the battery. [0003] Although the traditional method also uses the Thevenin equivalent c...

AI Technical Summary

Problems solved by technology

[0003] Although the traditional method also uses the Thevenin equivalent circuit model of the battery to estimate the limit power value, there are the following defects in the estimation process: 1) The electromotive force (EMF) of the battery is a parameter value calculated through the experimental test look-up table, which is different from that of the battery The state of charge (SOC) corresponds to the temperature, and is greatly affected by the accuracy of the SOC when calculating the look-up table; 2) In the battery pack, due to the existence of battery consistency problems, the error will increase when estimating the limit power of the battery pack, which is likely to cause The battery is damaged; 3) The polarization voltage change during the pulse process is not taken into account in the calculation of the polarization voltage. The limit current is relatively large, and the polarization voltage change is also large, which will increase the error when estimating the limit power and easily cause battery damage.

In this technical scheme, the Thevenin equivalent circuit of the battery is also used, but there are the following deficiencies in data processing, because the equivalent capacitance value in parallel with the polarization resistance can not be obtained, it is omitted, simply using the polarization resistance and The current calculation of the polarization voltage will lead to a large error in the calculation result of the polarization voltage, which will lead to a large error in the estimation of the limit power; the calculation process ignores the existence of the hysteresis voltage, which will increase the calculation error; use the average operating voltage as the battery The electromotive force further increases the estimation error of the limit power, etc.

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