A differential feedforward control of output current for high performance virtual synchronous generator in microgrid

Abstract

This paper concentrates on the load disturbance in three phase microgrid inverter (MGI) with an isolated transformer based on virtual synchronous generator (VSG) control. The transformer can provide the VSG with inductive output impedance when placed behind the LC filter. But the load disturbance may lead to steady-state error and poor dynamic performance with only capacitor voltage feedback control. The capacitor voltage differential feedback control is proposed to damp the output LC filter resonance and thus increases the system stability margin. The output current differential feedforward control is proposed to eliminate the influence of load disturbance then obtains error-free steady-state output and excellent dynamic responses. These theoretical findings have been eventually verified experimentally both on simulation and laboratory prototypes.