Resonance Point Tracking Control in High Step-Up Isolated DC-DC Converter with 5-Stage Cockcroft-Walton Circuit

Abstract

At present, it has become necessary to reduce the size of electron beam irradiation devices, which are utilized in many industries. This paper investigates a high step-up isolated DC-DC converter. This converter has the 5-stage Cockcroft-Walton circuit with an inductor in the secondary side. The inductor prevents a drastic changes in the transformer current and produces peak value of the output voltage with the LC resonance of the secondary side. In this paper, resonance point tracking control is proposed for the converter. The proposed control utilizes the LC resonance characteristics of the converter. The LC resonance in the secondary side is tracked by the proposed control regardless of load change. Therefore, the distortion of the transformer current is suppressed and the peak value of the output voltage is maintained by the resonance point tracking control. In addition, the validity of the proposed control is experimentally verified by demonstrating its transient behavior under load fluctuation.