Novel Resonant Power Feedback DC-DC Converter

In this article, a novel soft-switched isolated dc-dc converter topology is proposed that consists of a main power converter using a standard topology, augmented with a resonant power feedback circuit. The power feedback circuit utilizes a fraction of the output power to regulate the input voltage of the main converter. Input voltage regulation proves to be advantageous in applications where wide range of source voltage variations are experienced, such as in photovoltaic microinverters. The operation of main converter with a regulated input voltage results in a near-constant phase-shift angle and a high-frequency current wave shape with a low root mean square value over the entire range of operating conditions. Moreover, the operation with near constant phase-shift angle and the presence of additional resonant current in the feedback circuit extend the range of soft-switched operation of semiconductor devices in the converter. The proposed converter topology and its theoretical analysis is verified through an experimental prototype.