Series resonant ZCS-PFM DC-DC power converter with high-frequency high-voltage transformer link for high-power or magnetron drive

This paper presents a single lossless inductive snubber-assisted ZCS-PFM series resonant DC-DC power converter with a high-frequency high-voltage transformer link for industrial-use high-power magnetron drive. The current flowing through the active power switches rises gradually at a turned-on transient state with the aid of a single lossless snubber inductor, and ZCS turn-on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high-frequency high-voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high-frequency high-voltage transformer and the magnetizing inductance of the high-frequency high-voltage transformer. As a result, this high-voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high-voltage DC-DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. (C) 2005 Wiley Periodicals, Inc.