Sinusoidal PWM techniques comparison for the Quasi-Y-Source Inverter

Abstract

Impedance networks inverters (INI) have emerged as an alternative to improve traditional inverters, allowing their operation as a buck-boost type converter, through the utilization of the "shoot-through" conduction state, where switches of one or more inverter legs are gated on simultaneously. Recently introduced, the Quasi-Y-Source inverter (QYSI) is a magnetic coupled INI that has particular performance advantages, specially for renewable sources and distributed generation. To control the QYSI there is several techniques based on Sinusoidal Pulse Width Modulation (SPWM), that are modified to allow the shootthrough state. This work aims to present, through computational simulations, a comparative analysis of three SPWM techniques applied in three-phase QYSI, considering a fixed boost factor and a three-phase/three-wire RL load connected to the inverter output. The following modulation techniques were compared: Simple Boost Control (SBC), Maximum Boost Control with third harmonic injection (MBC3h) and Maximum Constant Boost Control with third harmonic injection (MCBC3h). Simulation results show operation characteristics of the QYSI for the dierent modulation techniques. A Fourier analysis was performed in order to evaluate harmonic distortion and harmonic spectrum for both inverter output voltage and current, and a comparative analysis was performed showing several relationships among voltage gain, switch voltage stress, shoot-through duty ratio and modulation index for the different SPWM techniques. Simulation results shows the advantages and disadvantages of each SPWM technique applied to QYSI and the impact of the coupled inductor on inverter performance, helping to establish proper criteria for choosing among SPWM techniques for different power systems applications.