Power Quality Control Strategy of Islanding Microgrid Under Distorted and Unbalanced Conditions

ABSTRACT

This paper presents a novel power quality control strategy for islanding microgrid contains multiple DG units under both distorted and unbalanced conditions. Actually the power quality of microgrid bus and the point of common coupling (PCC) are the main concerns due to the determination of high-quality power energy to the main grid and sensitive loads connected to microgrid bus. To tackle this problem, three control schemes based on PIR cascaded structure for DG units are developed to realize different control objectives. In these categories, the fundamental voltage is regulated by conventional PI controller to ensure direct voltage support and smooth operation mode transition while the harmonics or unbalanced variables are compensated with resonates controller in synchronous reference frame without sequential sequence decomposition. The proposed power quality control strategy that comprehensively utilization of these control schemes can satisfy power quality requirements of islanding microgrid, which is confirmed by simulation results considering both unbalance and distortion.

Keywords:

Microgrid, distributed generation, power quality, resonant controller, harmonics, unbalance, distortion.