Half-Cycle Control Method of the Bidirectional Three-Phase Dual-Buck Inverter Without Zero-Crossing Distortion

Abstract

The dual-buck inverter (DBI) does not have a shoot-through problem, and thus, the harmonics caused by the dead-time can be avoided. Besides, the DBI of half-cycle control can reduce the inductor current. However, half-cycle control would cause zero-crossing distortion (ZCD). This article discusses the working principle of DBI and the cause of ZCD. ZCD would lead to grid current distortion, which can be extracted by a high pass filter (HPF). Therefore, the negative feedback of grid current harmonic components can inhibit ZCD. In this article, the half-cycle control method without ZCD is proposed. The logic of half-cycle control is analyzed in detail. The ZCD formation process and the inhibition method is given by the quantitative switching model analysis. What is more, the influence on the control system of the method is discussed. Finally, a simulation model and a prototype of the three-phase DBI have been built to verify the theoretical analysis.