Quasi-Single-Stage Current-Fed Resonant AC-DC Converter Having Improved Heat Distribution

This article presents a quasi-single-stage current-fed resonant ac-dc converter having improved heat distribution. Secondary-side switches are turned off with the voltage closed to zero at high instantaneous power and with the voltage closed to the half of the output voltage at low instantaneous power. Switching losses at the primary-side bottom switches are reduced; this change improves the heat distribution over the switches. The primary-side duty-cycle fixed at 0.5 results in negligible input current ripple; this trait can significantly reduce the size of filter inductor at the grid side. Experimental results show the effectiveness of the proposed ac-dc converter and its improved heat distribution against a conventional solution.