Performance Evaluation of Isolated Three- Phase Differential Flyback Inverter with Ripple-Free Input Current for Grid-tied Applications

DC-AC inverters with voltage boosting capability are widely utilized in many applications for power conversion requirements especially for low/medium PV applications. In this paper, performance evaluation and parameters design of the isolated three-phase differential flyback inverter (TDFI) is presented. The proposed TDFI draws a ripple-free input DC current considering a small input film capacitor, which mitigate the requirement for bulky electrolytic capacitor at the input DC side and enhances its reliability and lifetime. In addition, the TDFI offers number of merits such as; reduced passive and switching components, compact size, voltage boosting-bucking property, and enhanced footprint. Moreover, cascaded low-pass filter (LPF) is used for second-order harmonic elimination (SOHE). The proposed SOHE strategy improves the grid currents THD to meet the harmonic standard limits. In addition, SOHE eliminates the third order harmonic component from the input current, which allows a ripple-free input DC current for grid integrated solar PV applications. The single carrier based control scheme of the proposed TDFI has been experimentally verified at 1.6 kW, 200 W, and 50 kHz switching frequency.