X射线管用高压电源设计及H_∞切换控制方法研究

发布时间：2018-11-19 11:42

【摘要】：X射线自发现以来在工业、农业和军事等领域得到广泛应用。传统X射线管用高压电源多采用油式或工频整流模式,体积庞大、功耗高、效率低；国外同类产品成本高、维修困难。因此本文将智能MCU与高频电源技术相结合,开发出一套稳定可靠X射线管用高压电源,实现最高-30KV直流电压、最大2.5mA直流管电流可调稳定输出,并对其稳压控制方法进行研究,具有十分重要的意义。本论文主要研究内容如下：(1)系统需求分析。对现场设备实际运行数据进行分析,与同行业先进设备对比,总结问题所在点,提出设备改进性能指标。即实现最高-30KV直流电压、最大2.5mA直流管流可调稳定输出,纹波小于0.1%,体积小,鲁棒性良好等。(2)系统总体方案设计。根据需求分析制定系统软硬件总体方案及控制总体方案,并进行可行性验证分析。即控制器选用FPGA,通过驱动PWM脉宽调制、逆变、谐振、高频变压、倍压整流及反馈采样等环节,搭建电源闭环控制系统,实现高压、管流稳定输出。根据系统变结构特性,选用H∞切换控制方案。(3)系统总体方案硬件平台搭建。采用模块化原则,对总体方案进行模块解析,搭建硬件平台。主要为FPGA最小系统及外围驱动两部分,外围驱动又分为AD/DA、PWM脉宽调制、逆变、谐振、高频变压、倍压整流等；以及CAN总线、UART串行通信接口。主要对其进行器件选型、电路设计及参数计算等。(4)系统总体方案软件平台搭建。采用模块化编程,主要为FPGA内核驱动及上位机开发两部分。与外围接口模块对应,FPGA内核驱动分为时钟管理、AD/DA、FIFO、CAN总线以及UART等模块,以VHDL语言对其编写控制时序。上位机选用C#语言,VS2008编译环境,通过NI控件搭建用户控制界面。(5)系统先进稳压控制方法设计与仿真研究。利用机理建模法对被控对象进行数学建模,分别设计PID控制及H∞切换控制系统,利用Matlab仿真,比较两类控制方法的动态性能和稳态指标,以验证H∞切换控制在本系统中的优势。
[Abstract]:X-rays have been widely used in industrial, agricultural and military fields since their discovery. The traditional high voltage power supply for X-ray tube uses oil or power frequency rectifier mode, which is large in volume, high in power consumption, low in efficiency, high in cost and difficult in maintenance. Therefore, combining intelligent MCU with high frequency power supply technology, a set of stable and reliable high voltage power supply for X-ray tube is developed in this paper. The maximum 30KV DC voltage and the maximum 2.5mA DC current adjustable and stable output are realized. It is of great significance to study the method of voltage stabilization control. The main contents of this thesis are as follows: (1) system requirement analysis. This paper analyzes the actual operation data of the field equipment, compares with the advanced equipment in the same industry, summarizes the problems, and puts forward the performance index of the equipment improvement. That is to achieve the highest 30KV DC voltage, the maximum 2.5mA DC current adjustable and stable output, ripple less than 0.1, small volume, good robustness and so on. (2) system overall design. According to the requirement analysis, the system hardware and software overall plan and the control overall plan are worked out, and the feasibility analysis is carried out. That is to say, FPGA, is used to drive PWM pulse width modulation, inverter, resonance, high frequency voltage change, voltage doubling rectifier and feedback sampling to set up a closed loop control system of power supply to realize high voltage and steady output of pipe flow. According to the variable structure characteristic of the system, the H 鈭，

本文编号：2342212