Research on Harmonic Voltage Compensation in Microgrid Based on Hierarchical Control Approach

In order to deal with such issues as three-phase voltage unbalance and harmonic distortion at sensitive load bus in an islanded multi-inverter paralleled microgrid (MG), a hierarchical control strategy is proposed based on two stationary αβ frame to compensate harmonic voltage in this paper, in which the controller includes DG local controller and MG central controller. In addition, the DG local controller can allocate fundamental power and harmonic power of microgrid by using advanced virtual impedance loop and traditional droop control strategy. Furthermore, the secondary central controller of MG generates voltage unbalance and harmonic voltage compensation reference signals, and transfers it to the DG local controller to control the output voltage of inverter. Then three-phase voltage unbalance and harmonic voltage compensation of mcirogrid are achieved. In the end, MTALB/Simulink software is used to build simulation platform to verify the validness and superiority of the proposed contral strategy.