Analysis and design of a wide range ZVS/ZCS push–pull DC/DC converter with voltage clamped

Abstract

Abstract A new isolated zero‐voltage switching (ZVS)/zero‐current switching (ZCS) push–pull (PP) DC/DC converter is presented. One auxiliary switch S3 and a clamping capacitor Cc are introduced at the primary of the conventional push–pull converter and a voltage doubler‐rectifier is adopted on the secondary side. This proposed converter has the features: (1) Switching losses are reduced significantly owing to zero‐voltage switching of primary switches and zero‐current switching of secondary diodes over a wide load range variation. (2) The voltage spike across all of the power devices can be clamped that enable the use of low‐voltage, low‐performance, and lower‐cost devices. (3) The energy stored in the transformer leakage inductance is used for the soft‐switching action and no additional resonant inductor is required. (4) A voltage doubler‐rectifier is employed to remove the problem of the diode reverse‐recovery effect and reduce the duty cycle loss that provides a much higher voltage conversion ratio. These merits make this simple converter provide an attractive solution for a distributed power system, uninterruptible power system, or battery charge/discharge system. The detailed operation, analysis, design, comparative study, and experimental results for the proposed converter are presented and a 600 W prototype was developed to verify the discussed theoretical analysis.