An interleaved high step-up DC-DC converter with reduced voltage stress across semiconductors

The high voltage gain converter is widely employed in renewable energy conversions such as photovoltaic and fuel cell power generation systems. An interleaved high step-up DC-DC converter with coupled inductor and voltage multiplier cell is proposed in this paper. The voltage multiplier cell is composed of two diodes, two capacitors and two coupled inductors. During the switch-on interval in each phase, the corresponding capacitors are charged in parallel by the coupled inductors. Similarly, during the switch-off interval in the same phase, the corresponding capacitors are discharged in series to pump their energy to the load. In this way the proposed converter can achieve high voltage conversion ratio. Other features of the proposed converter are low voltage stress across the main switches due to clamp capacitors, lower voltage stress across diodes compared to the conventional converters, low input current ripple due to interleaved structure, and alleviation of the diodes reverse recovery problems. Switches with lower R_DS-ON can be used that decreases conduction losses. The principle operation of the proposed converter is given by detailed mathematical analysis. Performance of the proposed converter is validated by simulation results in PSCAD-EMTDC.