Z-impedance enhanced trans-Z-source inverters with switched

Abstract

Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. This research work proposes a new topology for high-boost trans-Z-source inverter. In traditional trans-Z-source inverters for high boosting voltage, low modulation index is required, so under these conditions output voltage will have low quality with high total harmonic distortion. In order to achieve high DC-link voltage with low shoot-through duty cycle the new topology has added two transformers, two capacitors and three diodes to the Z-impedance network. With low shoot-through duty cycle and less active and passive components the new topology produces output voltage with high quality and low THD. Meanwhile in compare to other high boost topologies the proposed scheme, for the same boost factor and the same output power, has smaller transformer size and smaller capacitance and so this leads to inexpensive inverter. Comparison between the proposed topology and previously proposed schemes in terms of voltage stress on diodes and capacitors, and SDP factors of diodes has been made and the results verify the priority of proposed topology. The operating principle of the proposed topology along with transformer leakage inductance effects on voltage gain is analyzed in detail. Both simulation and experimental results verify the performance of the proposed inverter.