Overcurrent Suppression by Power Feedback Control Manipulating Angular Frequnecy for VSG Inverter

An overcurrent suppression method by power feedback control manipulating angular frequency is proposed for a Virtual Synchronous Generator (VSG) controlled inverter. The VSG inverter, which is a voltage-controlled type, has the drawback that it is easily prone to overcurrent in case of a large power disturbance. In order to suppress the overcurrent, two strategies are taken in this paper. The first is that the overcurrent of the VSG inverter immediately after the power disturbance is suppressed by virtual impedance that adaptively changes in accordance with the output power. The second is that subsequent overcurrent is suppressed by power feedback control by directly manipulating the angular frequency of the VSG so that the output power does not exceed the rated capacity. The effectiveness of the proposed method was demonstrated through numerical simulation and experiments using a down-scaled system.