Grid-Connected Novel Quasi Z-source Inverter

Background: To aim at the deficiencies of traditional Z-Source Inverter (ZSI) with its voltage boost conversion ability being limited and huge inrush current existing during the startup under shoot-through state, a novel switched inductor type ZSI topology is proposed in this paper. Methods: The ZSI presented applies the change of working state of the diode in switched inductor to deliver the energy stored in the inductor to the loads during the shoot-through state such that the boost capacity of the inverter is enhanced, and the voltage stress on capacitor is reduced, dramatically. In addition, we also establish the corresponding mathematical model and design the relative control strategy, and then apply it in wind power system with Permanent Magnet Synchronous Generators (PMSG). Conclusion: Compared with the traditional ZSI, the simulation results indicate that the ZSI proposed not only can effectively improve voltage boost ability of the inverter to make the fan run in a wider range of wind speed, but also reduce the voltage stress on capacitor of the impedance network, dramatically, such that the cost of the converter device is for that reduced, and is a quite effective and available ZSI.