Bidirectional DC-DC Control Strategy for Photovoltaic Energy Storage based on Fuzzy Second-Order Active Disturbance Rejection

Abstract

A bidirectional DC-DC converter (BDC) control strategy rested on fuzzy second-order linear active disturbance rejection control (FS-LADRC) is proposed to make independent photovoltaic energy storage system (IPESS) better adapt to various external conditions. The linear model of IPESS is constructed. Rested on the control characteristics of BDC on the energy storage side, traditional voltage and current double closed-loop control (VCDCC) is used. PI control is adopted for the current loop, and second-order linear active disturbance rejection control (LADRC) is adopted for the voltage loop. Fuzzy adaptive logic is combined with linear state error feedback (LSEF) control rate, so that the system has higher control accuracy. Compared with traditional PI control and traditional LADRC, the stability of direct current busbar (DCB) voltage and the power generation performance of the system under different conditions are analyzed by changing the intensity of PV irradiance. Simulation results illustrate that FS-LADRC is more excellent to traditional PI and LADRC control strategies in improving the steadiness of DCB voltage, power generation performance and of the system.