Applying Diode-Capacitor Voltage Multiplier to Coupled-Inductor Boost Converter for Novel DC-DC Converter with High Voltage Gain and Low Voltage Stress

By applying two diode-capacitor voltage multipliers (VMs) to the conventional coupled-inductor boost converter, a novel non-isolated DC-DC converter is obtained, which is suitable for renewable generation systems. The proposed converter has the following features: a large DC conversion ratio with moderate duty cycle, recycling leakage inductance energy by a VM and clamping low voltage on the switch, and thus using low voltage rating switch with low on-resistance to minimize conduction losses. The derivation of the proposed converter as well as the DC steady-state analysis including calculations of the DC gain, voltages stress and conduction losses are presented in detail. A comparison with available converters of similar structures demonstrates the superiorities of the proposed converter. A converter prototype with a 25 V input, 400 V output, 16 times of the voltage step-up gain at the nominal duty cycle 0.5 is designed and built up. Experimental results are in accordance with simulations. The converter achieves 94.1% power conversion efficiency at the nominal output of 200W.