High Power Soft Switching DC Power Supply For X-ray Machine

With the development of modern medicine, X-ray machine provide strongtechnical support and guarantee for some human disease diagnosis and treatment. Theapplication is more and more widely. The existing X-ray machine frequency is very lowand size is large. The whole efficiency is very low, and useless soft rays make the imagequality is poorer. X-ray machine high voltage power supply output voltage rise time isvery long, which make doctors and patients damage increased. So, people’s demand ofthe X-ray machine is more and more.The X-ray machine high voltage power supply is an important component of theX-ray machine. The frequency and voltage of the controllability decided the X-raymachine imaging quality and disease diagnosis range. This paper does a deep researchon the influence factors of the output voltage characteristics and frequency of highvoltage source in X-ray machine. Separately from the theory analysis and systemsimulation model, which combined with concrete experimental platform. Thoroughlystudy on X-ray machine imaging quality of factors, and the theory simulation resultshave been verified.Firstly, this paper analyzes the high voltage power supply of X-ray machinestructure and working principle. On the analysis of the influence X-ray machineimaging factors. Two-phase interleaved Boost power factor correction(PFC) and fullbridge LLC resonance converter have been used in medical high voltage power supplyof X-ray machine.Analyzed the two-phase interleaved Boost PFC working principle and introducedits advantages. Designed the circuit parameters. For the Choose two phase interleavedPFC control chip UCC28070. The periphery circuit of UCC28070and its controllerhavebeen designed. Solve the design difficulties high-power PFC.The inverter using LLC resonance converter. On the one hand, by changing theswitch frequency adjust output voltage, On the other hand to make the switch tubeachieve soft switch, reducing switching loss. Analyzes the principle of LLC resonanceconverter and realization the soft switch conditions. The fundamental harmonicapproximation model is established.The parameters of the main circuit have beendesigned. The parameters optimized. Solve the high frequency switching loss. Using theLLC resonance circuit,which reduce the transformer size, making the transformer design relatively simple.In the high voltage part, considering the distribution parameters of high voltagetransformer for designing. The high voltage transformer insulation and productionprocess have been designed, which reduced the influence of the distributed capacitance.Because the non-linear characteristics of the X ray tube, using Saber simulationsoftware established its equivalent model. Then the system simulation has been carriedout considering actual working condition. At the same time, building the experimentcircuit. Simulation and experimental results show that the X-ray machine high voltagepower supply switching frequency is high, and the output voltage adjusted continuouslywithin40kV~120kV. The X-ray power supply is proposed to achieve a quick rise andlow ripple of output voltage.