Resarch On The Design Of High Voltage Power Supply And Its Voltage Control Methods For X-ray Tube

X-ray has been widely used in industry and medicine since it was found. Traditionally,the low-freqency transformer and multiple voltage rectifiers are used to generate the DC high voltage for X-ray tube.These conventional types of X-ray sources are bulky in physical size and inefficiency and the control accuracies of the output voltages are not always satisfactory.The development of a high-frequency X-ray source using switching power-supply technology and digital control technology is discussed in the thesis.The voltage control method is also studied in the thesis.The main contents of this thesis are as follows:(1) The thesis expounds the background of subject in the first place.The thesis introduces the principle of generating X-ray and the ?-? character of X-ray.On the foundation of analyzing high voltage power supply system for X-ray tube both home and abroad, the performance of the high voltage power supply and its realization strategy are presented.The thesis also introduces the overall structure design of hardware and software of the system.(2) The control system of the high voltage power supply for X-ray tube is designed.The system takes the microprocessor DSP chip TMS320F2812 as the core, to realize the functions such as steady DC high voltage/steady tube current output, over voltage/over current protection and DC high-voltage/tube current display ete. Communicating with PC by means of CAN-bus, the microprocessor aeeeptes the remote control signal from the PC and sents the feedback voltage/current sampling converted data to PC.(3) The hardware circuit of high voltage power supply for X-ray tube has been research and developed.The function of leading modules of the hardware circuit are analyzed earnestly and each module of the circuit design method and parameters calculated are recommended in detail. Software is developed on the basis of hardware.Initialization procedures and functions of each module are introduced.(4) The thesis studies on system voltage stability control method.In order to obtain the high stability of the output voltage, the closed-loop control should be used in high voltage power supply. The system based on the PID control method to realize the regulation, control effect on the sliding mode variable structure control in this system are discussed.Based on the mathematical model of a open-loop system, using Matlab/Simulink simulation, to compare the dynamic performance and robustness of two kinds of control method.Simulation results show that the sliding mode variable structure control has the advantage in this system.