Voltage quality improvement of microgrids under islanding mode

This paper proposes a control strategy to reduce the voltage unbalance in microgrids. The voltage unbalance compensation is achieved by injection of a proper negative-sequence current into the microgrid. This task can be done by each inverter connected to the microgrid. The current compensation reference is obtained through a negative-sequence voltage control loop, avoiding the load current measurement. This strategy does not require any hardware modification. This new control strategy is simulated in Matlab/Simulink to prove its effectiveness. Experimental results are also provide.