DC Bus Voltage Control Strategy in AC and DC Hybrid Micro-grid System

For the fluctuation of direct current (DC) bus voltage of micro-grid system caused by the fluctuation, intermittent, uncertainty of distributed energy resources(DER), a strategy of controlling the voltage of DC bus was proposed. In order to suppress the power fluctuation of DC side and stabilize the DC bus voltage, an energy storage system combined with interleaved Bi-directional DC/DC converter and battery was employed. With the purpose of maintaining the battery voltage and controlling the DC bus voltage, the bidirectional DC/AC (alternating current, AC) converter was adopted. The double-closed loop control strategy which was consisted of voltage outer loop and current inner loop, was used to control the DC bus voltage and charging/discharging current of battery. The models of different working patterns were established on platform MATLAB/SIMULINK.The results show that the proposed control strategy is effective and feasible for suppressing the power fluctuation of DC bus.