Novel Approaches for Phase-Shift Control and Harmonics Reduction in H-Bridge Z-Source Inverter

Phase-shift control is a common approach to voltage control of traditional H-bridge inverters, but this method has not been used to voltage control of H-bridge Z-source inverter (ZSI) so far. This paper proposes a new phase-shift control method for H-hridge ZSI, which its main difference with phase-shift control of traditional H-hridge inverters is existence of four shoot-through states (short circuit of the H-hridge) in each switching cycle. One of the advantages of proposed method is simultaneous elimination of several harmonics by choosing the appropriate switching angles. Also, with using this phase-shift control method, the amplitudes of low order harmonics for many values of switching angles are less than the amplitudes of low order harmonics in traditional H-hridge VSI. A detailed description of suggested method and comparison with the traditional method are presented in this paper. Simulation results are given to demonstrate the new features of the proposed method.