Control strategies of DC-bus voltage in islanded operation of microgrid

This paper focuses on the energy management system and stability of DC bus in both grid-connected and islanded operations in microgrid system. The microgrid system consists of wind turbines, photovoltaic panels, batteries and super-capacitors, also includes both AC and DC zones. Voltage of DC bus must be kept stable especially in islanded operation. In grid-connected operation voltage of DC bus is controlled by inverter. Real power from renewable energy generations and storage system can be transferred to AC zone through DC bus. In islanded operation, inverter must be controlled to keep magnitude and frequency of AC bus stable, so storage system is used to regulate voltage of DC bus. Simulation results in the paper show that voltage of DC bus can be kept steady and power can be kept balance with the strategy in microgrid system.