A non-isolated high step-up DC-DC converter with soft switching using coupled inductor

Photovoltaics are important kinds of renewable energies. In this paper a new high step-up DC-DC converter is proposed based on coupled inductor as a voltage booster. The secondary side of coupled inductor is connected to the switches to increase voltage gain and improve soft switching operation. Due to Special structure of the converter, smaller diodes and capacitors can be used. The operation modes of proposed converter are discussed, the voltage gain of converter is calculated and required conditions for soft switching is presented. Then a modified voltage gain is proposed which is applicable in a wide switching frequency range, up to resonant frequency and also is applicable to a wide range of recent proposed converters. The modified Voltage gain is used to demonstrate the dependency of different parameters on the voltage gain, such as capacitor, leakage inductance, duty cycle and switching frequency. Simulation results are presented to validate the characteristics of the proposed converter and finally the main features of the converter is reviewed in conclusion.