Output voltage regulation based on P plus resonant control in islanded mode of microgrids

This paper investigates the inverter output voltage regulation method for islanded mode of microgrids. When DG (distributed generation) based inverters operate in islanded mode, the inverter can supply the full local load demand. Hence, the microgrid can be defined as a voltage source and regulate the output voltage. If an inverter supplies the power to the nonlinear and unbalanced loads, it generates the high order harmonics to the output voltage. Therefore, in this paper, P+multi resonant control which has large gain on the narrow band of specific frequency has been considered additionally for the performance improvement of output voltage regulation instead of the simple fundamental component control. Furthermore, the controller design method which satisfies the stability and performance of the system depending on the control gain parameters has been suggested after considering the effect on system. Improved THD performance of P+multi resonant control is verified through the PSiM simulation. It is also compared and analyzed with the fundamental component PI method and the PI method with harmonics compensation.