Virtual admittance Based Current Control Strategy for Grid-connected inverters in Microgrid

Integration the distributed energy resources into the microgrid is developed in a rapid pace. Conventionally, the voltage-source inverters in microgrid with sinusoidal current regulation are used in grid-connected mode. In this paper, a two-degree-of-freedom nonsinusoidal current control strategy is proposed for both the distributed power generation and power quality enhancement. The equivalent Thevenin-Norton circuit is presented to clarify the concept that the proposed strategy with virtual admittance leads to the power quality improvement. It is demonstrated that without any harmonic current sensor or additional compensating device, the harmonics of the voltages at the point of common coupling and currents in microgrid can be mitigated significantly. Time-domain performance evaluation results confirm the concept.