Design Of High Voltage Power Supply And Research Of H_∞ Switched Control Method For X-ray Tube

X-ray has been widely used in industry, agriculture and military since it was found. Traditionally, the low-frequency 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. Similar foreign products are expensive and difficult to be repaired. The development of a high-frequency X-ray source using switching power-supply technology and intelligent microcontroller control technology is discussed in the thesis, which reach the system-output of -30KV DC voltage and 2.5mA electric current. The voltage control method is also studied in the thesis. All of these are of great significance.The main contents of this thesis are as follows:(1) Requirement analysis of the system. The thesis analysis the actual operational data from the field devices, compares with advanced equipments from other companies, summarizes the important point of the problems and puts forward the improved index as follows: A new device with the maximum output of -30KV DC voltage and 2.5mA electric current and a ripple coefficient of 0.1%, which are all adjustable, the smaller fluctuations and volume.(2) Scheme design for the system overall. According to the demand analysis, the thesis formulate overall plan for the software, hardware and the control system and then make feasibility analysis. In the project, FPGA is used as the controller, PWM mode implementation, inverter circuit, resonance, high frequency transformer, dual voltage rectifying and sampled-data feedback are also included. According to variable structure features of the system, H∞ control algorithm is chosen in the thesis.(3) Hardware platform for the system. By the modularizing design principle, the thesis builds the hardware platform. Minimum system of FPGA and peripheral drivers are the main parts. AD/DA, PWM mode implementation, inverter circuit, resonance, high frequency transformer, dual voltage rectifying and sampled-data feedback are included in the peripheral drivers.(4) Software platform for the system. By the modularizing design principle, the thesis builds software platform. The kernel driver of FPGA and the machine interface are the main parts. In correspondence with peripheral interface module, The kernel driver of FPGA concludes AD/DA、FIFO、CAN and UART with the hardware description language VHDL. The machine interface is designed by C#.(5) Advanced voltage stability control method. The mechanism modeling method is used for modeling the object. The thesis designs PID control method and H∞　control algorithm for the problem. Simulating by MATLAB, the dynamic performance and the robustness are compared to verify the advantage of H∞, control algorithm in this project.