A New Driving Method for a Magnetron Tube Using Phase-Shifted Half-Bridge Converter

This article studies the design of a power modulator for driving a magnetron tube. In this design thepower modulator works with the half-bridge structure, series resonator and phase shift control method.In this scheme, by controlling the switching phase shift,the balance condition of magnetization current issatisfied and the maximum amount of core saturation current is reduced. As a result, the current stress of switches is reduced and switching and core losses are reduced. So, the size, weight and the cost of thecore of the power transformer will reduce. Also, using leakage inductance of the power transformer, the series-resonance circuit is provided soft switching condition is guaranteed. Suggested power modulator,is able to control the peak and average output power with the minimum loss. The maximum power of a microwave oven is about 1000 w and its average power is 250 W which is controlled proportionally to theinverter on-state periods. Other advantages to the proposed design are simplicity of the power circuit,decrease in the number of switching elements, decrease in the switching losses, and decrease in the leakage inductance of the power transformer. The design results have been verified through simulated ofthe PSCAD software and laboratory tests.