摘 要
逆變式焊接電源具有體積小、重量輕、節(jié)能省材、效率高、電氣性能好、易于實現(xiàn)智能化控制等諸多優(yōu)點，成為焊接電源發(fā)展的必然趨勢。本文通過對目前國內(nèi)外點焊逆變式電源發(fā)展現(xiàn)狀及所存在的問題進行分析和總結(jié)，提出了軟開關(guān)點焊逆變電源主電路拓撲結(jié)構(gòu)和數(shù)字化、智能化的控制方法，為點焊逆變電源向著高效率、智能化的方向發(fā)展提供了理論基礎。
當前實際生產(chǎn)應用中點焊逆變電源的主電路多采用硬開關(guān)方式，功率開關(guān)器件開關(guān)應力大，損耗高，從而降低了電源的利用效率，對此，軟開關(guān)技術(shù)大大緩解了這一難題。本文對軟開關(guān)點焊逆變電源主電路的多種拓撲結(jié)構(gòu)進行了對比分析，選用移相全橋零電壓零電流(PS-FB-ZVZCS)軟開關(guān)主電路，詳細介紹了其軟開關(guān)實現(xiàn)過程，并給出了電路模型和關(guān)鍵元器件的參數(shù)設計。選用數(shù)字信號處理器(DSP)作為主電路控制核心，在系統(tǒng)的工作過程中，實時采集負載電流值(在硬件電路中轉(zhuǎn)換為電阻兩端的電壓值)，通過控制算法計算，輸出相應的移相PWM驅(qū)動波形，通過調(diào)節(jié)對角線上兩個功率開關(guān)同時導通的時間實現(xiàn)電源的恒電流控制。針對當前手動PID調(diào)節(jié)的弊端，提出了模糊神經(jīng)網(wǎng)絡PID智能控制方法，模糊神經(jīng)網(wǎng)絡根據(jù)其輸入量，通過網(wǎng)絡計算輸出該時刻相匹配的PID參數(shù)進行PID控制，同時根據(jù)控制指標不斷修正連接權(quán)值，使下一時刻的系統(tǒng)輸出量更接近期望值，如此反復的運行，在線優(yōu)化控制參數(shù)，實現(xiàn)輸出量的實時調(diào)整，最終根據(jù)系統(tǒng)運行狀態(tài)實現(xiàn)點焊逆變電源的恒電流控制。
本文搭建了點焊逆變電源的系統(tǒng)模型，實現(xiàn)了模糊神經(jīng)網(wǎng)絡PID的智能化控制方法。利用實驗室條件模擬了逆變電源模型，設計了PWM驅(qū)動電路及電路采樣板并給出了具體的工作原理分析，利用DSP產(chǎn)生相應的移相PWM波驅(qū)動橋式電路，實現(xiàn)了逆變電源的恒電流控制。
實驗證明，模糊神經(jīng)網(wǎng)絡PID能根據(jù)系統(tǒng)運行狀態(tài)在線優(yōu)化PID參數(shù)，實現(xiàn)電源的恒電流控制，對點焊逆變電源智能化控制技術(shù)的發(fā)展具有一定的意義。

關(guān)鍵詞 點焊逆變電源；數(shù)字化；模糊神經(jīng)網(wǎng)絡；移相PWM；恒電流


Abstract
There are many advantages of inverter welding power, such as small volume, little weight, low energy, high efficiency, good electrical performance, easy to realize intelligent control and so on, so inverter welding power has been an inevitable trend of welding power. The paper put forward the soft switching circuit topological structure and digital, intelligent control method through the analysis on the present situation and existing problems of domestic and foreign inverter welding power, which provided theory basis for the development of inverter welding power to be high efficiency and intelligent.
In the present time, the main circuit of spot welding inverter power in the practical application is hard switching. The big switching stress and high loss of the switching devices lower the power efficiency. However, the research on soft switching technique indicated a new method to solve the problem. Through the comparative analysis of kinds of soft switching circuit topological structure, the main circuit of phase shifting-full bridge-zero voltage zero current (PS-FB-ZVZCS) was selected. The paper introduced the realizing process of soft switching, circuit model and parameters design of key components in detail. The control core was digital signal processor (DSP), and in the practical system, collecting the real time load current(in the hardware circuit, collecting the voltage of the resistance), dealing with it according to the algorithm and then output corresponding phase-shifting PWM to drive the switches to realize the constant current control. In view of the drawbacks of traditional PID, The paper put forward a new control algorithm Fuzzy-Neural Network-PID. When detecting inputs, computing them according to fuzzy neural network, output three corresponding matching parameters of PID, and then doing PID control, meanwhile, feedback the error between the reference and the output of the system to fix the connecting weights, and finally realizing the real time adjustment in line with the status of the system.
The article built the system model of spot welding inverter power, and achieved the intelligent control algorithm of fuzzy neural network PID on line. Designed PWM driving circuit and sampling circuit, introduced their working principle, produced phase-shifting PWM of DSP to drive the whole bridge circuit, and fulfilled the constant current control of inverter power.
The results indicated that, Fuzzy-Neural Network-PID algorithm could achieve the parameters of PID matching and constant current control according to the running system, which had certain significance to the development of the intelligent control technology of the spot welding inverter power.

Key words spot welding inverter power; digital; fuzzy neural network; phase-shifting PWM; constant current


目 錄
摘 要 I
Abstract III
第1章 緒論 1
1.1 課題的背景和意義 1
1.2 點焊逆變電源的發(fā)展現(xiàn)狀及趨勢 2
1.2.1 點焊逆變電源的發(fā)展現(xiàn)狀 2
1.2.2 點焊逆變電源的發(fā)展趨勢 3
1.3 智能控制技術(shù)在點焊中的應用 3
1.4 本課題的研究內(nèi)容 4
第2章 軟開關(guān)點焊逆變主電路拓撲結(jié)構(gòu)及工作原理 5
2.1 軟開關(guān)技術(shù)在點焊逆變主電路中的應用 5
2.1.1 軟開關(guān)技術(shù) 5
2.1.2 軟開關(guān)技術(shù)應用于點焊逆變主電路 7
2.2 軟開關(guān)點焊逆變主電路拓撲結(jié)構(gòu) 7
2.3 點焊逆變電源主電路 8
2.3.1 逆變主..