Fast Voltage Balance Control Strategy of Microgrid Inverter Operating in Islanded Mode

Abstract

The system voltage of microgrid operating on islanded mode, is normally supported by numerous microgrid inverters within the network, where output voltage quality of the inverters will directly affect the power supply quality in the network. Due to large numbers of loads are single-phase loads in microgrid, it is difficult to maintain three phase loads in the actual system keep the same and thus system loads resemble unbalance. Furthermore, this load unbalance is a dynamic variation because loads switching on or off is random, which will cause output voltage of microgrid inverter unbalanced. In order to improve the dynamic unbalanced performance of microgrid inverter, a feedforward control strategy is proposed in this paper. With this control strategy, inverter can instantaneously compensate unbalanced voltage and always keep output voltage balance even if there is a sudden large load change. Simulation results verify the feasibility and validity of the proposed control strategy.