Optimal Operation for Supercapacitor Storage System Using Piecewise LQR Voltage Equalization Control

Abstract

A closed-loop piecewise linear quadratic regulation (PLQR) voltage equalization controller is proposed for a supercapacitor storage system to optimize supercapacitor operation in terms of voltage differences among supercapacitor cells with the desired voltage tracking. In this study, under constant current charging mode, a model system is built based on the switched-capacitor method. The state equation of the errortracking system is derived. By adopting an idea derived from Lyapunov elliptic domains, the PLQR algorithm is proposed to change the feedback gain dynamically to satisfy the control input constraints. Simulation results verify the effectiveness and feasibility of the proposed algorithm.