An Isolated Ripple-Free Input Current Resonant Interleaved High Step-Up DC–DC Converter With Active Voltage Quadrupler for Renewable Energy Systems

Abstract

This paper presents an isolated resonant high step-up DC-DC converter with ripple-free input current (RFIC). At the low-voltage side (LVS), an interleaved current-fed bridge is employed while its switches are operated with a constant duty cycle of 0.5 to achieve RFIC. By active clamp circuits, firstly, the zero voltage switching (ZVS) is ensured for LVS switches; secondly, the stored energy of the leakage inductance is recycled; and thirdly, the voltage stresses across the switches are clamped at the value of 2V_IN that is much lower than the high output voltage. The last item enables the implementation of low voltage rated switches with low ON-state resistance. Through an active voltage quadrupler (AVQ) at the high-voltage side (HVS) and a transformer, the voltage gain is significantly extended. The switches of the AVQ are responsible for voltage gain regulation and experience half of the output voltage during the OFF-state. Due to the provided resonance by the auxiliary inductor and multiplier capacitors, the currents of the body diodes of the HVS switches smoothly reach zero, diminishing the reverse recovery losses. The steady-state analysis of the proposed converter is presented in detail and is validated by the fabrication of a 400W 40–400 V prototype with 96.1% peak efficiency.