Abstract
This paper presents a novel power quality enhancement strategy for microgrid with multiple distributed generation (DG) units under both distorted and unbalanced conditions. The power quality of microgrid alternating current (AC) bus is important as sensitive loads are connected to the point of common coupling and it is the interface between microgrid and the main grid. To tackle power quality problem, three DG unit control schemes based on proportion integration resonance (PIR) cascaded structure are developed to realize different control objectives. Frequency analysis and performance evaluation show the flexible and seamless transition of these control schemes. The proposed power quality enhancement strategy can satisfy power quality requirements of microgrid in various operation modes. In addition, it guarantees the robust and smooth operation of microgrid under both unbalanced and distorted conditions.