Active clamped three-phase isolated boost converter with series output connection for high step-up applications

A new active clamped three-phase isolated boost converter is presented for the high step-up DC-DC converter applications such as fuel cells, photovoltaic and battery sourced power conversion systems. The proposed converter employs the parallel three-phase input and series output structure to handle the high input current and high output voltage. This structure is suitable for generating the high output voltage using relatively low PWM duty and transformer turns ratios, which provides the high efficiency and low device stress. Moreover, the zero voltage switching (ZVS) is also achieved using an active clamping circuit. The operational principle and key waveforms of the proposed converter are presented. The considerations for the design and implementation are also discussed. The experimental results for a prototype converter with a 600 W power rating, 24 V/380 V input/output voltages are provided to show the validity of the proposed converter scheme.