An Improved Space Vector PWM for Z- Source Multi-Level Neutral Point Inverter Drive

This paper presents an improved space vector PWM (SVPWM) for Z Source Multi-level inverter, which offers a single-stage power conversion by using single impedance (Z) network to boost its output AC voltage through shoot-through (ST) and non-ST. Nevertheless, the states of ST limit the modulation index and cause a huge ST current in the inverter phase legs. The Z networks are directly responsible for balancing the inductive boosting voltage and output levels. The existing methods use the full ST which occupies the more switching commutations per cycle and it leads to unequal charging and discharging of inductor, causes more harmonics in the output voltage and currents. This work proposes a development of an improved SVPWM technique to balance the charging and discharging of inductors of Z network with DC link capacitors. The proposed method is validated through simulations and experimentally on 2kW prototype through FPGA environment with existing schemes. Its performance has examined with induction motor drive.