Design of phase-shifted parallel-input/series-output dual inductor-fed push-pull converter for high-power step-up applications

A new high-power step-up converter based on the phase-shifted parallel-input/series-output (PISO) modular converter with two dual inductor-fed push-pull converters is proposed. It is operated at a constant duty cycle and the output voltage is controlled with a phase-shift between the modules. It shows an output voltage which is high and linear to the control input, and a low switch turn-off stress resulting in a significant improvement in the efficiency. It also shows low ripple contents, fast dynamics, and low root-mean-square (RMS) currents in the output capacitors. The operation and features are analyzed and the mathematical models are derived. The design guidelines of a closed-loop 50 kHz, 400-1200 W, 18-30 Vdc to 310 Vdc prototype and the experimental results are provided to confirm the validity of the proposed converter.