A New Soft Switching DC-DC Converter With High Voltage Gain Capability

In this article, a new high step-up dc-dc converter with zero voltage switching (ZVS) capability is presented for renewable energy applications. In order to achieve high voltage gain without extreme duty cycles or a high turns ratio, a combination of a coupled inductor and switched diode-capacitor voltage multiplier cells is used. In the presented converter, only an auxiliary winding with a diode that operates under zero current switching (ZCS) is utilized to realize ZVS for two power switches, and an active clamp circuit is utilized to reach ZVS for the other power switches. The leakage inductance of the coupled inductor controls the current falling rate of the voltage multiplier and output diodes, and also they turn-on under ZCS condition. Hence, reverse recovery losses of the diodes are reduced. The voltage stress on the power switches is low, and low voltage rating switches can be adapted to reduce the losses of their conduction. Finally, a 1-kW experimental prototype setup with 50 V input voltage and 470 V output voltage is built to verify the converter performance.