Small signal modeling and transient analysis of a Trans quasi-Z-source inverter

This paper proposes, analyses and validates, both computationally and experimentally, an AC small signal model for a Trans quasi-Z-source inverter working in continuous conduction mode (CCM). For the implementation of the small-signal model, the dynamics of the particular Trans-qZSI network components have been considered. The presented AC small signal model is used for a detailed analysis of the performance of the Trans-qZSI topology, involving various aspects; a parametric study of the influence of the passive components on the dynamic response of the Z network, as well as the influence of their associated losses. Duty cycle and load variations are studied too, for Z topology operating point performance analysis. The AC small-signal model is then used to design a compensator for a closed-loop control scheme. Computer simulation results are presented to validate the model and the control method, comparing PSIM Trans-qZSI detailed simulations to the MATLAB derived results. Finally, experimental validation is achieved for the AC model in a low-medium power Trans-qZSI design, both in time and frequency domain. According to experimental results analysis, a snubber circuit is designed too, for the converter.