【正文】 that makes the operation visual and very easy. The singlechip microputer can also do the work independently。 the welded join tresistance value is over the limit。 Welding power source 1. Introduction The bridge band is an electric heat?ring ponent used for rocket launching. The band has to link up with the end surface of four columns for transmitting current by welding. The band material is a high temperatureresistant ni chrome with a thickness of mm. The column material is a fellable alloy or copper alloy with a diameter of mm. The welding of the band and column belongs to the precise spotwelding of different species of metallic foil and wire. Because of the special usage of the product, the requirements of the spotweld strength, splash control and quali?ed rate are very high. Condenser energystorage spotwelding has been used traditionally. There is an only upper electrode, and the column acts as both the work piece and the lower electrode in this situation. The difference in the physical properties and dimensions between the bridge band and column is signi?cant. This makes the temperature distribution of the welding zone very uneven. The high temperature zone is close to the side of the column, but does not lie on the nter face of the band and the column. Experiments have demonstrated that the bridgeband spotwelding process is highly sensitive to the welding current waveform, but the current waveform control ability of the condensertype spotwelder is very limited and cannot meet the welding quality requirements. There is also a clear splash in the welding process that is absolutely not allowable. Therefore, a new kind of spotwelding power source in which the output current waveform can be adjusted arbitrarily and precisely has been developed ?rst. Controlled by a 8098 singlechip microputer, the Mosfet precise spotwelding power source can deliver output 安徽建筑大學(xué) 畢業(yè)設(shè)計(jì)（論文） 32 currents with an arbitrary wave form. The current waveform adjustment range is 0–600 A and 0– ms, the adjustment precision being A for the current and ms for the time. The power source can deliver not only three pulse current waveforms, which include a preheating, welding and tempering pulse in turn, but also any special and plex current waveform, by accurate control of the current instantaneous value. This makes welding possible by using the optimum current waveform. This new kind of spotwelder can meet entirely the strict requirements of bridgeband spotwelding. An industrial PC has also been used to monitor and manage the welding process and the various parameters, which will further improve the behaviour of the spotwelder. 2. Main circuit design of the power source The main circuit structure is shown in Fig. 1. A parallel power Mosfet group is used to adjust the current wave form. The Mosfet is designed to work in a linear state, so the instantaneous value of output current waveform can be controlled precisely. Mosfet is a kind of voltagecontrolled ponent and is easy for parallel use, which simpli?es the circuit greatly. There are no secondary breakdown problems with Mosfet, which makes the power source more reliable. The chief defect in using Mosfet in a linear state is that the power loss is higher than that in the on–off state, but both the absolute value of the output current and the duty cycle of this power source are very low, and so the power loss is not very high. KT and KV sensors are used to sample the welding current and voltage. The program ?ow chart of the singlechip micro puteris shown in Fig. In addition to presetting and controlling the welding current waveform arbitrarily and precisely, they stem can also carry out a selfcheck and give an alarm when some Mosfet are damaged。 Waveform control。感謝他們生活上給我的支持和照顧，在學(xué)習(xí)上給我的關(guān)心和鼓勵(lì)，我才能安心，順利的完成大學(xué)學(xué)業(yè)。 再次，我要感謝大學(xué)四年所有教過(guò)我的老師和我們的輔導(dǎo)員，感謝他們四年來(lái)對(duì)我的教誨和幫助。最重要的是指導(dǎo)老師教會(huì)我們?cè)S多分析、解決問(wèn)題的方法，這在書本中無(wú)法學(xué)到的，他的教誨培養(yǎng)了我科學(xué)的思維方法和一絲不茍的治學(xué)態(tài)度，淵博的學(xué)識(shí)更使我受益匪 淺。無(wú)論是軟件的使用，還是理論的運(yùn)用，我都有很大的收獲。 安徽建筑大學(xué) 畢業(yè)設(shè)計(jì)（論文） 29 參考文獻(xiàn) [1] 王兆安，劉進(jìn)軍 . 電力電子技術(shù)，機(jī)械工業(yè)出版社， [2] 朱正行等 .電阻焊技術(shù) ， 機(jī)械工業(yè)出版社 ， 2020. [3] 殷樹言等 .逆變焊接電源及現(xiàn)代焊接技術(shù)現(xiàn)狀與思考 ， 電焊機(jī) ， 2020. [4] 張光先 .逆變焊機(jī)原理與設(shè)計(jì) ， 機(jī)械工業(yè)出版社 ， 2020. [5] 屈穩(wěn)太 .大功率 IGBT 高頻逆變電焊機(jī)的研究 ， 電力電子技術(shù) ， 2020. [6] 李國(guó)峰，王寧會(huì) .電源技術(shù)，大連理工大學(xué)出版社， [7] 陳明 . 中頻逆變電阻焊電源的研制，安徽理工 大學(xué) , 2020. [8] 王福生 .國(guó)內(nèi)外電阻焊設(shè)備的發(fā)展 ， 電焊機(jī) ， 2020. [9] 宋文清 .沈陽(yáng)工業(yè)大學(xué)逆變電阻焊主電路動(dòng)態(tài)過(guò)程分析及設(shè)計(jì)， 沈陽(yáng)工業(yè)大學(xué) ， 2020 [10] 劉照偉等 .電阻點(diǎn)焊質(zhì)量監(jiān)控技術(shù)的發(fā)展現(xiàn)狀和趨勢(shì) ， 電焊機(jī) ， 2020. [11] 耿正等 .電流型脈寬調(diào)制控制的逆變點(diǎn)焊機(jī)研制 ，焊接， 1999. [12] 歐燕 .基于 DSP 的數(shù)字化 IGBT 逆變點(diǎn)焊電源控制系統(tǒng)的研究 ， 武漢理工大學(xué) . [13] 王東，馮曉云 .中頻逆變直流電阻焊優(yōu)勢(shì)探討 ， 電焊機(jī) ， 2020. [14] 林渭勛 .現(xiàn)代電力電子電路， 浙江大學(xué)出版社 ， 2020. 安徽建筑大學(xué) 畢業(yè)設(shè)計(jì)（論文） 30 致謝 我要感謝所有曾經(jīng)寄予我關(guān)心和幫助的人，這篇論文的完成和他們中的任何一位都是分不開的。 研究展望 隨著我國(guó)科教興國(guó)和人才興國(guó)發(fā)展戰(zhàn)略的實(shí)施，大力推進(jìn)創(chuàng)新發(fā)展的思路，電阻焊機(jī)的自動(dòng)化以及效率一定會(huì)越來(lái)越高，應(yīng)用也會(huì)越來(lái)越廣泛。該研究成果能 最大限度的提高功率因數(shù)，保證焊接質(zhì)量， 并且此類焊機(jī)在焊一些特殊材料，如鋁，鋁合金，鍍鋅板等，焊接效果優(yōu)良。 并 通過(guò)上述這些波形我們可以得出這次主電路的設(shè)計(jì)符合預(yù)期。 500V/10V 降壓 后的二極管 應(yīng) 設(shè)置為快速二極管，我們可以得出以下波形，如下圖 所示。 500V/10V 降壓后 的仿真分析 變壓器選擇了副邊為 2的變壓器，并把變壓器設(shè)置成 500V/10V；下圖 為變壓后的電壓波形。仿真結(jié)果如下圖 所示： 圖 逆變電路產(chǎn)生的電壓波形 如上圖所示：我們可以看到在 的過(guò)程中總共有 10 個(gè)波頭，也就是說(shuō)頻率已經(jīng)改變成 1000hz 符合我們?cè)O(shè)計(jì)成中頻的要求。60KVA 濾波電容 C=4400uf 電阻 R=；仿真出的結(jié)果如下圖 所示： 圖 安徽建筑大學(xué) 畢業(yè)設(shè)計(jì)（論文） 25 由上圖可知，預(yù)計(jì)的整流波形與仿真出來(lái)的波形相似，符合設(shè)計(jì)要求。所以，我們需要單獨(dú)建立一個(gè) RCD 模塊。由于該仿真工具箱的模型非常齊全，例如電源我們可以直接采用三相電源模塊，整流橋我們可以直接采用整流橋模塊，另外，我們也可以選用 IGBT 來(lái)搭建逆變橋等等。 中頻逆變電阻焊電源的仿真模型 根據(jù)第二章和第三章介紹的工作原理和電路圖，在 MATLAB/Simullink 的環(huán)境安徽建筑大學(xué) 畢業(yè)設(shè)計(jì)（論文） 23 中建立了中頻逆變電阻焊電源。最重要的是它還有各種專業(yè)的學(xué)科性的工具箱，如電力系統(tǒng)仿真模塊 (Simpowersystems)、控制系統(tǒng)工具箱 (Controlsystem)、信號(hào)處理工具箱 ( Signal Processing Toolbox)等。既適用于定常系統(tǒng)也適用于時(shí)變系統(tǒng)。 Simulink 這一名詞本身 就包含了建模(Link 即對(duì)模塊進(jìn)行連接 )與仿真 (Simulation)這兩大功能。 MATLAB 中的 Simulink 動(dòng)態(tài)仿真集成環(huán)境是以 MATLAB為基礎(chǔ)的用于動(dòng)態(tài)系統(tǒng)建模和仿真的軟件包，它是由