Advanced microgrid power control through grid-connected inverters

Recently, researches on microgrids have attracted more and more attention all over the world. Numerous studies and experiments about microgrid converters have been done. This paper presents a method to improve the power quality by controlling the real and reactive power flow between the main grid and the microgrid through the grid-interfaced inverter. Firstly, the desired values of I_d and I_q can be obtained by transforming the currents into d-q stationary frame and decoupling the active and reactive power for the use of both traditional proportional-integral (PI) and feedforward control. Besides the traditional direct power control (DPC), model predictive control (MPC) has emerged as one powerful method to obtain the active and reactive power needed directly with some clear advantages to the system such as higher reliability and enhanced stability. Both PI with feedforward and MPC methods to control the grid-interfaced inverter have been studied and simulated in this paper.