Current sourcing ZCS magnetron driver for low input voltage applications

The use of topologies that have an output current sourcing behavior could be advantageous when driving constant voltage loads that call for the stabilization of the output current rather than output voltage. The load characteristic of the magnetron considered in this study can be modeled as a voltage source of about 3.9 kV with a relatively small internal resistance of about 1.5 kOhm that needs to be driven by a current of about 300 mA. This study proposes a one-stage, zero current switched, high voltage gain, and current sourcing converter, to drive such a load. The topology is based on the parallel resonant converter but includes blocking diodes at the input bridge to assist the soft switching operation. The theoretical analyses were verified by simulations and experimentally on a 1.3 kW magnetron driver which was fed from a low voltage source in the range of 20 V to 32 V. The circuit was controlled by dsPIC30F2020 (Microchip, USA) in closed loop.