A Novel Switching Loss Analysis of Coupled-Inductor Impedance-Source Inverters

The Impedance-source inverters have been proposed for integrating voltage-boost, buck and inversion into a single stage with shared functionalities and hence lesser active switches. Recently, some of them even have coupled inductors included for raising gain, while retaining high dc-link utilization without extra components. However, leakage inductances of the coupled inductors have caused noticeable problems, like voltage spikes and resonances, during switching transients. These problems are not easy to analyze theoretically with traditional inverter models, because of tight topological integration within each impedance-source inverter. It is therefore the theme hereon to propose a novel model for analyzing transient and power losses of a coupled-inductor impedance-source inverter at each of its switching transitions. Readings from experiments have promptly verified the developed theoretical model for a coupled-inductor impedance-source inverter.