Autonomous Droop-Based Load Control in PV-Supplied DC Microgrids for Effective Power Sharing

PV-supplied DC microgrids (PV-DCMGs) are well suited to powering many off-grid applications. Droop control is an effective approach for managing sources in microgrids because it improves system reliability and scalability. However, conventional droop control may not satisfy the requirements of PV-DCMGs, in which loads must connect and disconnect dynamically according to solar-power availability. This paper proposes a droop-based method for operating multiple loads in a PV-DCMG. The line voltage serves as a signal for allocating power among the loads and determining their connection status. A key requirement is a smooth line-voltage transient to preserve stability and avoid unnecessary load connection or disconnection. The paper presents the control logic and procedures for sizing the bus capacitance to achieve effective and stable operation. It also analyzes the effects of key non-idealities in the DC-microgrid model and proposes mitigation methods. Simulation and experimental results demonstrate the effectiveness of the proposed control logic and component-sizing procedures for managing the available power in a PV-DCMG.