Dynamic Droop Gain Adjustment for Proportional Power Sharing in Low Voltage DC Microgrid

DC microgrid is becoming popular due to high efficiency, reliability and easy integration of renewable sources. Droop controller based distributed technique is used in dc microgrid for proportional power sharing among sources. However, due to interconnecting cable impedance, trade-off exists between power sharing accuracy and voltage regulation. Centralized controller achieves these objectives using communication between sources by sharing their reference power/current signals to sources. Use of central controller limits the reliability of system. To address this problem, a dynamic droop gain adjustment scheme is proposed in this paper. This technique uses decentralized controller with low bandwidth communication. Key advantages are proportional power sharing, low voltage regulation and high reliability. To evaluate the performance of the proposed scheme, detailed simulation studies are carried. A scaled down laboratory prototype is developed to determine the viability of the proposed controller.