Bus Voltage Control Strategy for Low Voltage DC Microgrid Based on AC Power Grid and Battery

One of the targets for operational control of DC microgrid is to guarantee the DC bus voltage constant. Considering DC microgrid on both grid-connected and islanding operating conditions, DC bus voltage control strategy was proposed based on ac power grid and energy storage systems. Through the reasonable design of external voltage loop and internal current loop control parameters for the both AC-DC converter and the DC-DC converter, the dynamic performance of the control system was improved, and the DC bus voltage was kept constant. The validity of the bus voltage control strategy was verified by the establishing Simulink model of DC microgrid. The results were shown that the response time of the bus voltage control strategy maintained within 100ms with the load fluctuation of DC microgrid, and the maximum ripple rate was 0.8%. Therefore, the final results were shown that the bus voltage control strategy is validity.