Isolated Zvs-Pwm DC-DC Converter Based on the Variable Capacitor Technique

Abstract

This paper introduces a new static power conversion principle, based on the variable capacitance of a capacitor arrangement. As an example of the proposed technique, an isolated ZVS-PWM dc-dc converter topology is proposed. Circuit operation and theoretical analysis, with emphasis on the soft-commutation process, are included in the paper. To validate the theoretical analysis and verify the operation of the converter, a proof-of-concept experimental prototype with 960W power rating, 400 V input voltage, 48 V output voltage and 100 kHz switching frequency was designed, constructed and tested in a laboratory. An additional attribute of the proposed technique is the reduction of the voltage across the power semiconductors to two-thirds of the dc bus voltage, when the duty cycle is equal to 0.5. The proposed technique can be extended and used to generate several other topologies of isolated and nonisolated dc-dc converters.