A decupled PQ control strategy of voltage-controlled inverters

This paper deals with problems caused by high distributed generation penetration and proposes a simple and precise PQ control strategy for voltage-controlled inverters in micro grids. The widely-used current-controlled inverters cannot provide voltage support for micro grids and have to develop seamless transfer strategy between gird connected mode and islanded mode. A voltage-controlled inverter is raised in the paper due to the problems. The new inverter can be regarded as a voltage source cascaded with controllable output impedance. By adopting a new phase-locked loop, the output voltage amplitude and frequency are well decoupled. Thus output active and reactive powers are decoupled satisfactory. The output response is fast and precise. The idea is verified by simulation and experiment results.