Design and simulation of a high fidelty multi-stage power converter for pre-heating of industrial magnetrons

Design and simulation of a multistage power converter, for generation of high fidelity controlled output for different pre-heating phases of an industrial magnetron filament, is discussed. Design caters for high currents of up to 200A at a very low voltage of 1.5 to 6V. Load regulations demand for a very stringent load curve following at multiple voltage steps and eventually a ramp down to steady state voltage of 1.5V at a predefined rate, a very low THD, robustness against random load variations, stable frequency response, and insensitivity against EMI and power line fluctuations. The proposed power converter consists of multiple stages including AC-DC, DC-DC and DC-AC stages. A Double Fourier series analysis is used to analyze the THD reduction of unipolar SPWM. The designed topology results in a very stable performance under most conditions. The final output of cascaded topology shows high fidelity adherence to load requirements and well within upper and lower bounds of the required voltage.