Non-isolated Ultrahigh Boost Ratio DCDC Converter with Coupled Inductor and Charge Pump

Abstract

This paper proposed a non-isolated, ultrahigh boost ratio DC-DC converter for low voltage photovoltaic power generation applications. A coupled inductor and a charge pump capacitor which operate in hybrid resonant mode are employed in the proposed topology. By transferring the inductive and capacitive energy simultaneously, ultrahigh step-up voltage gain can be achieved without large duty cycle. A lossless passive snubber circuit is used to recycle leakage energy of the coupled inductor and alleviate high voltage spike across the main switch. By operating under the hybrid resonant mode, low voltage and current stresses are achieved to the switches and snubber circuit. The duty cycle of the main switch can be operated within a wide range, which means a wide operation range of input and output voltage. In addition, all switches of the proposed circuit can achieve soft-switching operation. A 1-kW prototype circuit with input voltage of 20-30V and output voltage of 300V was implemented to verify the theoretical analysis and performance of the proposed converter.