A Hybrid Energy Storage System Controlled by Two Degree-of-Freedom PID for Wind Power Generations

In order to make the unstable three-phase power output of wind turbine can charge the lithium battery pack steadily through the control of topology circuit and controller, a hybrid energy storage system controlled by two degree-of-freedom (DoF) PID is proposed to realize stable charging of lithium battery pack in this paper. The circuit combines the control circuit, the detection circuit and the protection circuit to achieve normal charging of the lithium battery pack. The system model composed of each module is built and simulated by MATLAB/Simulink software. The simulation results show that when the unstable three-phase voltage of wind turbine varies in the range of 0.4V-400V, the hybrid energy storage system keeps the charge current of the lithium battery group within the range of the normal range of the 2.5A-3.5A. And the system can effectively charge the lithium battery pack with the unstable three-phase power output of wind turbine.