Voltage gain comparison of space vector modulated Quasi ZSI with traditional inverter topologies

Z-Source Inverter (ZSI) overcomes all the limitations of traditional Voltage and Current Source Inverters. Besides both buck and boost operation can be accomplished using ZSI. All advantages are made possible in ZSI by using an extra switching state called Shoot-Through state where the legs of inverter are shorted. A modified ZSI called Quasi Z-source inverter for renewable energy applications are investigated in this paper. In the first section, different PWM schemes like Simple Boost, Maximum Boost, Maximum Boost with Third Harmonic Injection, Maximum Constant Boost, Double Carrier PWM methods are reviewed. In next section, a novel maximum boost control method is presented based on the Space Vector Pulse-Width Modulation (SVPWM) technique for the three-phase Quasi Z-source inverter. Compared with the traditional carrier-based maximum boost control strategy, the SV method has a wider linear operation range, lesser switching loss and is easier for digital implementation. THD and voltage gains of schemes are compared. The simulation results in Matlab/Simulink as well as comparative performance of traditional VSI, ZSI and quasi ZSI have been provided and discussed, which have validated all theoretical analysis in the paper.