Research on Harmonic Suppression of New Controller in Islanding Mode of Microgrid

The proportional complex integral (PCI) controller can realize zero steady‐state error control of AC signals with specific frequencies in a static coordinate system. The frequency of the traditional power grid is relatively fixed, so the zero steady‐state error control of the AC signal is realized by adopting the PCI controller. With the increasing proportion of renewable energy generation, the frequency characteristics in the power system become uncertain. When the microgrid operates in island mode, the frequency of the fundamental wave and harmonics fluctuates greatly, which causes the PCI controller to fail to achieve zero steady‐state error control. This paper proposes two controllers: positive and negative sequence decoupling quasi‐proportional complex integral (PNDQPCI) controller and high‐order positive and negative sequence decoupling quasi‐proportional complex integral (HPNDQPCI) controller. The PNDQPCI controller can effectively control the positive and negative sequence voltage when the system frequency drifts; The HPNDQPCI controller can effectively suppress multiple harmonics. Finally, simulation and experiment are presented to verify the theoretical analysis as well as the feasibility and the superiority of the proposed controller. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.