The invention relates to a power
cell management system of an
electric vehicle, particularly relates to a method for estimating a charge state of a power
cell of the
electric vehicle and aims to improve charge state
estimation precision and charge state
estimation stability of the power
cell in the cell
management system of the
electric vehicle. The method comprises steps that an end
voltage and charging and discharging currents of the power cell are acquired; a
system model of the power cell is established; an
ampere-hour
integral method and state observers CDKF, AEKF and H infinity are employed to cooperate with the
system model to respectively estimate charge states of the power cell to acquire zk, Ah, zk, CDKF, zk, AEKF and zk, Hinf, weight calculation of the zk, Ah, zk, CDKF, zk, AEKF and zk, Hinf is carried out to acquire final
estimation values zk, zk=w1zk, Ah+w2zk, CDKF+w3zk, AEKF+w4zk and Hinf, and weight coefficients w1+w2+w3+w4=1. According to the method,
multiple methods are employed for estimation, the final estimation value is acquired through weight calculation, accuracy can approach 2%, most of accuracy can approach 1%, and properties of non-easy
divergence and high stability are realized.