Simplified SVPWM for Z Source T-NPC-MLI including neutral point balancing

Abstract

This study presents a Z Source-T shape - Neurtal point Diode Clamped (NPC) - Multi Level Inverter (MLI) power conversion system (Z-T-NPC-MLI) with the help of New Space Vector PWM (SVPWM) scheme. The proposed impedance source inverter combines the advantages of boosting and conversion of DC to AC power. There are several research papers on T-NPC-MLI producing the desired voltage conversion and with minimal switching and conduction losses. Though the reported research on Z-NPC-MLI SVPWM has dealt with reduction of Shoot through (ST) options and its predominance enhancement, it does not address the neutral point fluctuation problems on the DC-Link. This paper proposes an improved SVPWM scheme for Z-T-NPC-MLI with minimal ST state. The scheme exploits the redundancy switching vector option for both ST and regular switching, which offers a self-control neutral point fluctuation. Also the proposed SVPWM maintains the quarter symmetry and harmonic spectra. The deliberate Z-T-NPC-MLI with proposed SVPWM is simulated in MATLAB/SIMULINK environment, and the results confirm the advantages of the proposed inverter and its simplified PWM scheme.