Modeling and control of multi-parallel connected inverters in microgrids

In this paper, modeling and control of multi-parallel connected inverters are studied for microgrid. For the operation of paralleled inverters, the current sharing accuracy is important for the reliability of the system. In order to reduce the circulating current and achieve the power sharing accuracy, a novel decentralized communication-based droop controller is proposed for each energy source unit. Unlike the conventional droop control method, a PID controller is added to compensate the error value caused by the mismatched model parameters of inverters and different line impedance, which can fast achieve the current sharing accuracy and effectively enhance the power quality in spite of component mismatches. Simulation results from Matlab/Simulink verify that the proposed control strategy effectively solves the problem of circulating current between paralleled inverters.