Estimation method of charging state of lead acid power battery of electrical vehicle

Abstract

The invention relates to an estimation method of a charging state of a lead acid power battery of an electrical vehicle. Through detection of values of voltage and current of a direct current bus in a certain time, minimum direct current bus voltage and a direct current bus current which corresponds to the minimum direct current bus voltage within the time are counted and obtained. Generally, the direct current bus current which corresponds to the minimum direct current bus voltage is the maximum current value within the time. Effective electromotive force is calculated according to a simple internal resistance equivalent model, filter processing is conducted on the effective electromotive force through a filtering algorithm, influence of floating voltage of the lead acid battery and a transient error of estimation is eliminated, and due to the fact that an SOC of the lead acid power battery has an approximately linear relation with electromotive force, the current SOC of the battery can be obtained through a lookup table algorithm. According to the estimation method, only the direct current bus voltage and the current at a load end are based, simple and efficient algorithms are adopted, data of theory and actual tests of the lead acid power battery are referred at the same time, so that the SOC of the lead acid power battery can be accurately estimated out.

Description

technical field [0001] The invention relates to the field of electric vehicle control, realizes the estimation of the state of charge of the lead-acid power battery of the pure electric vehicle through a simple and effective algorithm, and specifically relates to a method for estimating the state of charge of the lead-acid power battery of the electric vehicle. Background technique [0002] The estimation of the SOC of the power battery of electric vehicles mainly includes ampere-hour measurement method, open circuit voltage method, load voltage method, internal resistance method, neural network method and Kalman filter method at home and abroad. At present, the most commonly used algorithm for electric vehicles is to use the open circuit voltage method combined with the ampere-hour measurement method. The Chinese patent document with publication number CN 101022178A discloses a "Status of Charge Estimation Method for Ni-MH Power Batteries Based on Standard Battery Model", w...

AI Technical Summary

Problems solved by technology

There are certain defects in this method. When the whole vehicle is in a state of continuous driving and the battery does not appear to be unloaded, there will be a large error in the calculation of EMF1, which will lead to a large error in the SOC estimation of the lead-acid battery.

In the same way, EMF2 is calculated by compensating the dynamic voltage of the whole vehicle, and the error of EMF2 itself is also relatively large, which eventually leads to a large error in the estimated battery SOC

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