A Control Strategy for Battery-Ultracapacitor Hybrid Energy Storage System
Zhang Chunjiang;Dong Jie;Liu Jun;Ben Bing;Key Lab of Power Electronics for Energy Conservation and Motor Drive of Hebei Province Yanshan University;
In distributed power generation system, energy storage system should possess high power density and high energy density simultaneously. Single kind of energy storage device is hard to meet the requirements. Hybrid energy storage system(HESS) is a good solution for this problem. Battery and ultracapacitor can complement each other in performance, and they are connected to DC bus by a corresponding bidirectional half-bridge converter in the paper. The battery maintains the voltage stability of the DC bus. The ultracapacitor provides the high-frequency components of all load of the DC bus to mitigate the impact when load changes. The detection method of the high frequency components of the load power is analyzed. The mathematical model of bidirectional half bridge converter and four kinds of mode control strategies are established. DSP is used to realize the integrated control of the energy storage system. The effectiveness of the control strategies is verified by the results of software simulation and experiments.