Selective output impedance based control for grid-connected inverters

Abstract

This paper proposes a power control loop strategy for Voltage-Source Inverters (VSIs), based on the use of abc frame PI controllers. Its physical behaviour and mathematical model are presented in detail and the inverter output impedance is derived to analyze the obtained disturbance rejection performance. The results show that the proposed scheme is capable of effectively rejecting disturbances originating from the grid voltage, achieving current THD as low as 2.45% even with a voltage THD of 28.3%.