A Simple Control Scheme for Improving Reactive Power Sharing in Islanded Microgrid

In this article, a simple control scheme based on an adaptive Q - V droop coefficient is proposed to improve the reactive power sharing amongst sources in an islanded microgrid. All the sources present in the network independently calculate and apply an adaptive Q - V droop coefficient after every step change in load, thereby achieving system-wide improved reactive power sharing. The core computation of the proposed method is based on the transient energy delivered by the respective inverter after every load change. The proposed control does not require communication; neither depends on the knowledge of feeder impedances nor requires measurements from distant nodes. Also, it can work satisfactorily irrespective of the location of the load change. Further, the strategy is also immune to any load change happening during the compensation process. A significant improvement in reactive power sharing has been achieved by using the proposed scheme without compromising the voltage regulation, and without causing significant power transients. The effectiveness of the proposed scheme has been validated by performing detailed simulation studies. Its viability is confirmed by carrying out experimental studies on a laboratory prototype.