Distortion in single phase current controlled PV inverters for grid connection

Abstract

Unipolar switched single-phase inverters experience lower switching losses and cause less EMI when compared with bipolar switched inverters. However, these benefits come at the expense of increased distortion in the current waveform near the voltage zero-crossing. Moreover, it is demonstrated in this paper that switching delay causes generation of low frequency harmonics in the current waveform. In spite of that, unipolar switched inverters can be designed to operate within harmonic limits specified by the Australian Standard 4777.2.