Modulation Strategy of Z-source Inverter Based on Asymmetric Shoot-through Vector Insertion Method

Abstract

The traditional Z-source inverter modulation strategy is usually symmetric. Symmetric modulation has a good effect in suppressing the second harmonic but also limits the possibility of modulation sequences. In this paper, an asymmetric modulation strategy is proposed, which uses the shoot-through vector only once in a switching period to maximize the optimization of the switching losses caused by the shoot-through vector. The current passing through the switching devices of the Z-source inverter is analyzed, and it is determined that the minimum number of shoot-through vectors in a switching period can achieve the lowest switching loss. On this basis, asymmetric switching sequences of several common modulation strategies are proposed. Finally, the effectiveness of the proposed modulation method is verified by Matlab/SIMULINK combined with PLECS simulation.