Dynamic Power Conditioning Method of Microgrid Via Adaptive Inverse Control

Abstract

Different microsources have different frequency regulation functions and capabilities. The droop control can allocate power among the microsources according to the operation demand during system dynamics; however, the steady-state frequency often deviates from the rated value because of the droop characteristics. To ensure the precise condition of power and the stability of frequency even in a low-voltage network, this paper puts forward an improved droop control algorithm based on coordinate rotational transformation. With the ability to accurately regulate the unbalance power, this method realizes self-discipline parallel operation of microsources. Furthermore, an adaptive inverse control strategy applied to modified power conditioning is developed. With an online adjustment of modified $P-f$ droop coefficient for the frequency of microgrid to track the rated frequency, the strategy guarantees maintaining the frequency of microgrid at the rated value and meeting the important customers' frequency requirements. The simulation results from a multibus microgrid show the validity and feasibility of the proposed control scheme.