A novel three-phase four-leg inverter based load unbalance compensator for stand-alone microgrid

Abstract

• This paper proposes a novel load unbalance compensator (LUC) for the stand-alone microgrid using three-phase four-leg VSI. • The model of a three-phase four-leg VSI for the LUC and the microgrid are simulated using PSCAD/EMTDC. • This demonstrates that the proposed LUC increases the stability of stand-alone microgrid under unbalance load conditions. This paper proposes a three-phase four-leg voltage sourced inverter (VSI) based load unbalance compensator (LUC) including its control algorithm, which is a component of a microgrid. The purpose of proposed three-phase four-leg VSI based LUC is to improve power quality of the standalone microgrid. Power quality of the microgrid which was installed in Mara-island, Korea is analyzed using a real operational data. In this work, the microgrid in Mara-island which includes a photovoltaic power generation system, a diesel generator, a battery energy storage system, and a power management system is modeled in PSCAD/EMTDC, and proposed three-phase four-leg VSI based LUC is also modeled and applies to the modeled microgrid. Power flow and stability of the modeled microgrid with the LUC is analyzed under variable irradiance and unbalance loads. The results show that the proposed LUC helps to improve stability of the stand-alone microgrid. The proposed three-phase four-leg VSI based LUC and its control algorithm can be effectively utilized to the stand alone microgrid which has large unbalance loads.