Adaptive Voltage Tuning Based Load Sharing in DC Microgrid

Distributed control of converters is important to achieve plug and play functionality in a dc microgrid. It must ensure proportional load sharing among converters and voltage regulation of the dc bus. Droop control is a conventional distributed control method to achieve load sharing among converters in a dc microgrid. It is realized by reducing the voltage reference, linearly or dynamically, as the load increases. This degrades the voltage regulation as the overall bus voltage decreases as the load increases. In this paper, a sliding mode control based adaptive voltage tuning method is proposed such that the voltage reference is adjusted dynamically above and below the desired dc bus voltage to achieve load sharing. This results in excellent voltage regulation, also the proposed control is realized locally hence it facilitates plug and play functionality. The per unit input current value is exchanged among the neighboring converters. The proposed controller is validated through simulation.