Supercapacitor Assisted DC Microgrid Voltage Regulation Using Multipoint Droop Control Mechanism

In a standalone DC microgrids, there should be balance between electricity supply and demand in real-time in order to maintain the system voltage. Energy storage management system plays an important role in fulfilling the demand-supply requirement to achieve this power balance. Energy storage management system can help the system to regulate the bus voltage. Droop control mechanisms used to manage storage elements like super-capacitor can improve voltage regulation. Supercapacitors have high rate of charging/discharging, high-power density, fast response, good efficiency and have long lifetime in energy conversion which make it suitable for high power applications. In this paper, a control scheme using multipoint droop control for a DC microgrid (MG) is proposed. The super-capacitor operates in charge or discharge modes based on certain specific voltage bandwidths over multipoint droop characteristics. The objective of the proposed control scheme is to maintain the DC bus voltage within a specified tolerance level and support current sharing among all the converters in the system.