Investigation On Switching Power Supply With High Voltage And High Power

High voltage DC power supplies are widely used in many fields. High voltage DC switching power supply with high frequency and high power are required by the development of many new technologies, such as numeric imaging of X-ray for medical use, compact pulsed power source etc. The technology of high voltage DC switching power supply has been successfully developed in advanced countries, but is under development in China. In this paper some technical questions of high voltage DC switching power supply were investigated by using theoretical analyses, numerical simulation and experiment.In chapter 2, the nonlinear feature of iron core of transformer in switching power supply was studied. According to the characteristics of switching power supply, the topology structure of resonant converter was selected. The characteristics of out put voltage and current vs. frequency for the three kinds of resonant converter were analyzed and compared.In chapter 3, according to the requirements of high voltage power supply used for charging capacitors with constant current, the Series Resonant Converter (SRC) was chosen as the main circuit frame. The dynamic process of SRC was discussed by using mathematical analyses and numeric simulation to study the operational Characteristics, the effects of parameters of resonant circuit on them and the relationship between switching frequency and out put power, which provided the bases of designing the power supply.In chapter 4, considering the features of high voltage transformer and the difficulties to make it, a reasonable design scheme with SRC was proposed, which efficiently reduced negative influence of distributing parameters of transformer on switching power supply and could completely utilize leakage inductance as resonant inductance.In chapter 5, the controller of resonant converter designed by myself, was introduced, in which Zero Current Switching (ZCS) had been realized. Experimental results showed that the controller was well suited to resonant converters with different frequencies, and had the advantages of high reliability, low wastage and low Electro Magnetic Interfere (EMI).At last, a high voltage power supply used for charging capacitors with constant current has been designed and completed. The operational Characteristics of this power supply were proved by experiments to be fully agreed with the designing targets.