【摘要】：X射線自發(fā)現(xiàn)以來在工業(yè)、農(nóng)業(yè)和軍事等領(lǐng)域得到廣泛應(yīng)用。傳統(tǒng)X射線管用高壓電源多采用油式或工頻整流模式,體積龐大、功耗高、效率低；國(guó)外同類產(chǎn)品成本高、維修困難。因此本文將智能MCU與高頻電源技術(shù)相結(jié)合,開發(fā)出一套穩(wěn)定可靠X射線管用高壓電源,實(shí)現(xiàn)最高-30KV直流電壓、最大2.5mA直流管電流可調(diào)穩(wěn)定輸出,并對(duì)其穩(wěn)壓控制方法進(jìn)行研究,具有十分重要的意義。本論文主要研究?jī)?nèi)容如下：(1)系統(tǒng)需求分析。對(duì)現(xiàn)場(chǎng)設(shè)備實(shí)際運(yùn)行數(shù)據(jù)進(jìn)行分析,與同行業(yè)先進(jìn)設(shè)備對(duì)比,總結(jié)問題所在點(diǎn),提出設(shè)備改進(jìn)性能指標(biāo)。即實(shí)現(xiàn)最高-30KV直流電壓、最大2.5mA直流管流可調(diào)穩(wěn)定輸出,紋波小于0.1%,體積小,魯棒性良好等。(2)系統(tǒng)總體方案設(shè)計(jì)。根據(jù)需求分析制定系統(tǒng)軟硬件總體方案及控制總體方案,并進(jìn)行可行性驗(yàn)證分析。即控制器選用FPGA,通過驅(qū)動(dòng)PWM脈寬調(diào)制、逆變、諧振、高頻變壓、倍壓整流及反饋采樣等環(huán)節(jié),搭建電源閉環(huán)控制系統(tǒng),實(shí)現(xiàn)高壓、管流穩(wěn)定輸出。根據(jù)系統(tǒng)變結(jié)構(gòu)特性,選用H∞切換控制方案。(3)系統(tǒng)總體方案硬件平臺(tái)搭建。采用模塊化原則,對(duì)總體方案進(jìn)行模塊解析,搭建硬件平臺(tái)。主要為FPGA最小系統(tǒng)及外圍驅(qū)動(dòng)兩部分,外圍驅(qū)動(dòng)又分為AD/DA、PWM脈寬調(diào)制、逆變、諧振、高頻變壓、倍壓整流等；以及CAN總線、UART串行通信接口。主要對(duì)其進(jìn)行器件選型、電路設(shè)計(jì)及參數(shù)計(jì)算等。(4)系統(tǒng)總體方案軟件平臺(tái)搭建。采用模塊化編程,主要為FPGA內(nèi)核驅(qū)動(dòng)及上位機(jī)開發(fā)兩部分。與外圍接口模塊對(duì)應(yīng),FPGA內(nèi)核驅(qū)動(dòng)分為時(shí)鐘管理、AD/DA、FIFO、CAN總線以及UART等模塊,以VHDL語(yǔ)言對(duì)其編寫控制時(shí)序。上位機(jī)選用C#語(yǔ)言,VS2008編譯環(huán)境,通過NI控件搭建用戶控制界面。(5)系統(tǒng)先進(jìn)穩(wěn)壓控制方法設(shè)計(jì)與仿真研究。利用機(jī)理建模法對(duì)被控對(duì)象進(jìn)行數(shù)學(xué)建模,分別設(shè)計(jì)PID控制及H∞切換控制系統(tǒng),利用Matlab仿真,比較兩類控制方法的動(dòng)態(tài)性能和穩(wěn)態(tài)指標(biāo),以驗(yàn)證H∞切換控制在本系統(tǒng)中的優(yōu)勢(shì)。
[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，

本文編號(hào)：2342212