A Double-Output Soft-Switched Step-Up AC/DC Bridge-Less Converter for Microwave Energy Application

This paper presents a converter that takes an AC input and provides both of the voltages required to power a magnetron. By utilizing a bridgeless PFC stage at the input that utilizes a DCM operated inductor, the converter is able to achieve high PF of 0.99 and reduced input rectifier conduction losses as well as sharing the switches of the PFC stage with those of a resonant converter. The converter utilizes a step-up parallel CL resonant circuit with voltage doubler output to achieve a high voltage for the anode-cathode connection, and an LLC resonant circuit to provide the step-down for the low voltage filament connection. The circuit is then verified through PSIM with a 1.55 kW typical power magnetron with a peak of 1.8 kW power.