Bidirectional flyback inverter with low output voltage THD

Abstract

This paper develops a single-phase voltage source inverter mainly containing a high frequency flyback bidirectional DC-DC converter - as a previous stage, and a full-bridge module. The flyback bidirectional converter generates a rectified sinusoidal voltage waveform across the output capacitor. The full bridge transistors switch two times in one AC period in order to transform the output capacitor voltage in an AC waveform. The converter ensures also galvanic insulation between input and output, and a possible high conversion voltage ratio given by transformer. A state-space averaging model for the proposed converter was used for stability analysis and to design a tracking controller for output capacitor voltage. Digital simulations validate inverter proper operations and a low output voltage THD value.