Modulation Techniques for a Modified Three-Phase Quasi-Switched Boost Inverter with Common-Mode Voltage Reduction

In a single-stage buck-boost quasi-switched boost inverter (qSBI), the shoot-through state insertion causes high amplitude common-mode voltage. Consequently, the qSBI becomes less attractive in transformerless photovoltaic (PV) systems. In this paper, a novel space vector pulse-width modulation for a modified qSBI is introduced to reduce the magnitude of common-mode voltage and push the modulation index up to 1. By properly choosing the shoot-through interval time, shoot-through states are considered to be inserted for boosting voltage and also reducing the THD value of the output voltage. The mathematical analysis and operating principles of the converter are discussed and verified through PSIM simulations. Finally, an experimental prototype is validated based on a TMS320F28335 DSP microcontroller and a DE0-Nano FPGA digital control platform.