A Family of High Step-Up A-Source Inverters with Clamped DC-Link Voltage

A family of novel impedance source inverters based on an auto-transformer is presented in this manuscript. The proposed topologies utilize minimal coupled inductors turns ratio to obtain high voltage boost ability in comparison with previous magnetically coupled impedance source inverters. The impedance source inverters using coupled inductors attain high voltage gain in smaller shoot-through interval compared to transformer-less group, but they suffer dc-link voltage spikes due to leakage inductances of their coupled inductors. So, in presented inverters, absorbing circuits are utilized to reduce these spikes. Besides that, absorbing circuits lead to higher voltage boost ability, lower shoot-through duty cycle and better modulation index. In addition, all the novel structures have continuous input current which is suitable for renewable energy sources such as fuel cell and photovoltaic systems. Theoretical analysis in steady state and simulation results are presented to verify the inverters performance.