State of charge estimation and state space model analysis of the Ni-MH battery system

Abstract

This paper deals with the design and modeling aspects of the Ni-MH (Nickle metal hydride) battery and measures the SOC (State of charge) using different methods. This research deals with mathematical modeling, analysis of stability, analysis of step response, ABCD matrix, controllability, observability and peak percentage of the battery system. In addition, the output of the battery model is observed in Simulink. After that, the critically damped state-space design method by using state feedback method is discussed and implemented in Simulink. The battery model is implemented in Simulink using DC machine for charge and discharge and two ways of SOC estimation discuss with implementation in Simulink. From the implementations of the two methods of the SOC measurements, it is concluded that the direct measurement method is a superior method to estimate the SOC of the battery.