Development of a novel power module based on pulse step modulation

Abstract The high voltage power supply (HVPS) based on pulse step modulation (PSM) has been widely used in various fusion auxiliary heating systems due to its many distinctive merits, but voltage overshoot remains too high to be solved heretofore. An improved type switch power supply (SPS) module is designed in this paper to reduce the voltage overshoot with no increase of rise time of the PSM HVPS. A novel bus voltage control method is adopted in this paper to realize almost no voltage overshoot, while an auxiliary control and protection system based on DSP is designed. After detailed analysis of the proposed module, a real module was manufactured with rated output of 750 V/25A to verify the performance of the proposed method. Experiment results indicate that overshoot voltage of the module is suppressed to less than 1%, in addition, the module could response to control signal within 1.2 μs to achieve fast dynamic adjustment and can be turned off within 3 μs when it fails. The proposed module can greatly improve the performance of PSM HVPS and provide power for accelerating and heating system of the China Fusion Experimental Rector (CFETR).