An Integrated Magnetics Design for an Isolated ZVS Cuk Converter

TL;DR

This paper introduces a novel integrated magnetics design for an isolated ZVS Cuk converter, optimizing flux cancellation and coupling to improve efficiency and switch operation.

Contribution

It presents a new integrated magnetics configuration with specific flux cancellation and coupling strategies for enhanced ZVS performance in an isolated Cuk converter.

Findings

Achieved 97.25% peak efficiency in a 0.5 kW prototype.

Designed magnetic core with specified coupling coefficients for optimal flux cancellation.

Validated the proposed design through experimental hardware testing.

Abstract

This paper proposes a new integrated magnetics (IM) design for an isolated zero-voltage-switching (ZVS) Cuk converter (IZCC). In this design, six magnets are wound onto a single magnetic core, and to minimize magnetic core size and losses, both direct current (DC) and alternating current (AC) flux cancellations are considered. The DC flux is fully cancelled, and the AC flux must be cancelled until a limited value such that the input and output inductor currents have enough ripple to provide the conditions for achieving ZVS on all switches. Therefore, the value of the coupling coefficients (CC) between the windings should be considered such that the minimum ripple to achieve ZVS for all the switches is available. The design is implemented on a simple magnetic U-core, and the CC values are specified based on the winding locations and arrangement. To validate the idea experimentally, a hardware prototype is proposed with a power of 0.5 kW, a switching frequency of 150 kHz, and a peak efficiency of 97.25%.