PR based output voltage regulation for harmonic compensation under islanded mode of microgrid with magnitude restoration

摘要

This study examines the P+ multi resonant based voltage control for the voltage harmonics compensation under the islanded mode of a microgrid. In islanded mode, the inverter is defined as a voltage source to supply the full local load demand without a connection to the grid. On the other hand, the output voltage waveform is distorted by the negative and zero sequence and current harmonics due to the unbalanced and nonlinear loads. In this paper, P+ multi resonant controller has been used to compensate the voltage harmonics. The gain tuning method is assessed by the analysis of the tendency of controller as the variation of gain. In addition, this study analyzes the slight voltage magnitude drop due to the practical form of the P+ multi resonant, and proposes the counter method to solve this problem by adding the PI based voltage restoration method. Furthermore, the proposed PR based harmonics compensation method has been extended to the droop based parallel operation which also supplies the nonlinear load. Finally, the proposed methods to compensate for the voltage harmonics are verified through the PSiM simulation and experimental results.