Modeling and Novel Modulation of Enhanced Z-source Inverter

In this paper, an Enhanced Z-source inverter is proposed. Compared to the traditional Z-source inverter, it can obtain high voltage conversion factor with a short shootthrough duration, and can decrease Z-source capacitor voltage stress significantly. In order to identify its inherent character, the transient modeling of continuous conduction mode (CCM) in dc side is presented. Through the detailed analysis, a right-half-plane zero is found in its control-to– output function. Moreover, an improved control method for the Z-source inverter is proposed in this paper. In comparison with traditional maximum constant boost control method, this improved control method has noticeable advantages. Not only switching frequency can be reduced significantly but also the volume of the Z source can be lessened as a result of six shoot through states per carrier period while obtaining the same voltage boost gain. Simulation and experimental results have demonstrated the validity of small-signal models and the merits of the proposed control method.