State of charge estimation based on active disturbance rejection control for power batteries in engine waste heat recovery system

Abstract

The Coulomb counting (CC) method is the most widely accepted state of charge (SOC) estimation method in the industry. However, the cumulative error generated during operation is a huge challenge for the engineering application. A feedback regulation framework is designed to address this situation; however, the basic problem of this framework is that the error regulation occurs only after the error is generated. As a result, its initiative to suppress system disturbance is insufficient. To overcome this problem, an active disturbance rejection control–based-feedback-estimator is proposed in this paper. The regulation is designed based on the terminal voltage error between actual measurement and theoretical value. And active disturbance rejection control is employed to improve the estimation accuracy and adaptability. The power batteries’ SOC estimation in engine waste heat recovery system is studied in this paper. Compared with the traditional CC method and a proportional–integral (PI) feedback estimation method, the proposed active disturbance rejection control-feedback-estimator exhibits better estimation performance and adaptability to system disturbances and uncertainties. There are only three parameters ${\omega }_o$ , ${\omega }_c$ , and $b_0$ to tune, and estimation performance can be maintained without having to retune parameters when boundary conditions change, proving the effectiveness of the proposed active disturbance rejection control-feedback-estimator.