Constant-frequency parallel-resonant converter

Abstract

A steady-state analysis of the constant-frequency parallel-resonant converter operating in the clamped mode is performed for the continuous-conduction mode of operation. Unified closed-form expressions are derived for circuit characteristics such as the resonant-capacitor voltage, the resonant-inductor current, control-to-output characteristics, boundary conditions for natural and forced communication, and the theoretical limits for clamped-mode operation. These characteristics are experimentally verified and simulated using the computer program IG-SPICE. Considerations for practical design based on hardware operating at 300 kHz with a 300 V input and a 5 V and 300 W output are discussed. The following advantages associated with the power converter are noted: ease of designing magnetic filter elements because of the constant-frequency operation; lower switching losses; lower conduction losses; and smaller size and weight due to the higher frequency operation.