直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)的研究外文翻譯

1、中國(guó)地質(zhì)大學(xué)長(zhǎng)城學(xué)院本科畢業(yè)設(shè)計(jì)外文資料翻譯 系 別信息工程系學(xué)生姓名專 業(yè)電氣工程及其自動(dòng)化學(xué) 號(hào)043111312015 年 3 月1 日外文資料翻譯譯文直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)的研究1概述直流電動(dòng)機(jī)具有良好的起、制動(dòng)性能，宜于在大范圍內(nèi)實(shí)現(xiàn)平滑調(diào)速，并且直流調(diào)速系統(tǒng)在理論和實(shí)踐上都比較成熟，是研究其它調(diào)速系統(tǒng)的基礎(chǔ)。而用MATLAB軟件對(duì)直流調(diào)速系統(tǒng)進(jìn)行虛擬環(huán)境下的仿真研究，不僅使用方便，也大大降低了研究成本。本文敘述了直流電動(dòng)機(jī)的基本原理和調(diào)速原理，介紹了直流電動(dòng)機(jī)開環(huán)和雙閉環(huán)調(diào)速系統(tǒng)的組成及靜、動(dòng)態(tài)特性，并且根據(jù)直流電動(dòng)機(jī)的基本方程建設(shè)立了調(diào)速系統(tǒng)的數(shù)學(xué)模型，給出了動(dòng)態(tài)結(jié)構(gòu)框圖，用工

2、程設(shè)計(jì)方法設(shè)計(jì)了直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)。最后，用MATLAB仿真軟件搭建了仿真模型，對(duì)調(diào)速系統(tǒng)進(jìn)行了仿真研究。 通過對(duì)直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)動(dòng)態(tài)特性的研究與仿真，可以清楚地看到，直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)具有較好的動(dòng)態(tài)性能，可以在給定調(diào)速范圍內(nèi)，實(shí)現(xiàn)無靜差平滑調(diào)速，這為直流電動(dòng)機(jī)調(diào)速系統(tǒng)的硬件實(shí)驗(yàn)提供了理論依據(jù)。2雙閉環(huán)直流調(diào)節(jié)系統(tǒng)的研究背景直流調(diào)速是現(xiàn)代電力拖動(dòng)自動(dòng)控制系統(tǒng)中發(fā)展較早的技術(shù)。在20世紀(jì)60年代，隨著晶閘管的出現(xiàn)，現(xiàn)代電力電子和控制理論、計(jì)算機(jī)的結(jié)合促進(jìn)了電力傳動(dòng)控制技術(shù)研究和應(yīng)用的繁榮。晶閘管-直流電動(dòng)機(jī)調(diào)速系統(tǒng)為現(xiàn)代工業(yè)提供了高效、高性能的動(dòng)力。盡管目前交流調(diào)速的迅速發(fā)展

3、，交流調(diào)速技術(shù)越趨成熟，以及交流電動(dòng)機(jī)的經(jīng)濟(jì)性和易維護(hù)性，使交流調(diào)速?gòu)V泛受到用戶的歡迎。但是直流電動(dòng)機(jī)調(diào)速系統(tǒng)以其優(yōu)良的調(diào)速性能仍有廣闊的市場(chǎng)，并且建立在反饋控制理論基礎(chǔ)上的直流調(diào)速原理也是交流調(diào)速控制的基礎(chǔ)?，F(xiàn)在的直流和交流調(diào)速裝置都是數(shù)字化的，使用的芯片和軟件各有特點(diǎn)，但基本控制原理有其共性。對(duì)于那些在實(shí)際調(diào)試過程中存在很大風(fēng)險(xiǎn)或?qū)嶒?yàn)費(fèi)用昂貴的系統(tǒng)，一般不允許對(duì)設(shè)計(jì)好的系統(tǒng)直接進(jìn)行實(shí)驗(yàn)。然而沒有經(jīng)過實(shí)驗(yàn)研究是不能將設(shè)計(jì)好的系統(tǒng)直接放到生產(chǎn)實(shí)際中去的。因此就必須對(duì)其進(jìn)行模擬實(shí)驗(yàn)研究。當(dāng)然有些情況下可以構(gòu)造一套物理裝置進(jìn)行實(shí)驗(yàn)，但這種方法十分費(fèi)時(shí)而且費(fèi)用又高，而且在有的情況下物理模擬幾乎是不可

4、能的。近年來隨著計(jì)算機(jī)的迅速發(fā)展，采用計(jì)算機(jī)對(duì)控制系統(tǒng)進(jìn)行數(shù)學(xué)仿真的方法已被人們采納。 但是長(zhǎng)期以來，仿真領(lǐng)域的研究重點(diǎn)是仿真模型的建立這一環(huán)節(jié)上，即在系統(tǒng)模型建立以后要設(shè)計(jì)一種算法。以使系統(tǒng)模型等為計(jì)算機(jī)所接受，然后再編制成計(jì)算機(jī)程序，并在計(jì)算機(jī)上運(yùn)行。因此產(chǎn)生了各種仿真算法和仿真軟件。由于對(duì)模型建立和仿真實(shí)驗(yàn)研究較少，因此建模通常需要很長(zhǎng)時(shí)間，同時(shí)仿真結(jié)果的分析也必須依賴有關(guān)專家，而對(duì)決策者缺乏直接的指導(dǎo)，這樣就大大阻礙了仿真技術(shù)的推廣應(yīng)用。MATLAB提供動(dòng)態(tài)系統(tǒng)仿真工具Simulink，則是眾多仿真軟件中最強(qiáng)大、最優(yōu)秀、最容易使用的一種。它有效的解決了以上仿真技術(shù)中的問題。在Simul

5、ink中，對(duì)系統(tǒng)進(jìn)行建模將變的非常簡(jiǎn)單，而且仿真過程是交互的，因此可以很隨意的改變仿真參數(shù)，并且立即可以得到修改后的結(jié)果。另外，使用MATLAB中的各種分析工具，還可以對(duì)仿真結(jié)果進(jìn)行分析和可視化。Simulink可以超越理想的線性模型去探索更為現(xiàn)實(shí)的非線性問題的模型，如現(xiàn)實(shí)世界中的摩擦、空氣阻力、齒輪嚙合等自然現(xiàn)象；它可以仿真到宏觀的星體，至微觀的分子原子，它可以建模和仿真的對(duì)象的類型廣泛，可以是機(jī)械的、電子的等現(xiàn)實(shí)存在的實(shí)體，也可以是理想的系統(tǒng)，可仿真動(dòng)態(tài)系統(tǒng)的復(fù)雜性可大可小，可以是連續(xù)的、離散的或混合型的。Simulink會(huì)使你的計(jì)算機(jī)成為一個(gè)實(shí)驗(yàn)室，用它可對(duì)各種現(xiàn)實(shí)中存在的、不存在的、甚

6、至是相反的系統(tǒng)進(jìn)行建模與仿真。自70年代以來，國(guó)內(nèi)外在電氣傳動(dòng)領(lǐng)域內(nèi)，大量地采用了“晶閘管直流電動(dòng)機(jī)調(diào)速”技術(shù)(簡(jiǎn)稱VM調(diào)速系統(tǒng))。盡管當(dāng)今功率半導(dǎo)體變流技術(shù)已有了突飛猛進(jìn)的發(fā)展，但在工業(yè)生產(chǎn)中VM系統(tǒng)的應(yīng)用量還是占有相當(dāng)?shù)谋戎?。在工程設(shè)計(jì)與理論學(xué)習(xí)過程中，會(huì)接觸到大量關(guān)于調(diào)速控制系統(tǒng)的分析、綜合與設(shè)計(jì)問題。傳統(tǒng)的研究方法主要有解析法，實(shí)驗(yàn)法與仿真實(shí)驗(yàn)，其中前兩種方法在具有各自優(yōu)點(diǎn)的同時(shí)也存在著不同的局限性。隨著生產(chǎn)技術(shù)的發(fā)展，對(duì)電氣傳動(dòng)在啟制動(dòng)、正反轉(zhuǎn)以及調(diào)速精度、調(diào)速范圍、靜態(tài)特性、動(dòng)態(tài)響應(yīng)等方面提出了更高要求，這就要求大量使用調(diào)速系統(tǒng)。由于直流電機(jī)的調(diào)速性能和轉(zhuǎn)矩控制性能好，從20世紀(jì)

7、30年代起，就開始使用直流調(diào)速系統(tǒng)。它的發(fā)展過程是這樣的：由最早的旋轉(zhuǎn)變流機(jī)組控制發(fā)展為放大機(jī)、磁放大器控制；再進(jìn)一步，用靜止的晶閘管變流裝置和模擬控制器實(shí)現(xiàn)直流調(diào)速；再后來，用可控整流和大功率晶體管組成的PWM控制電路實(shí)現(xiàn)數(shù)字化的直流調(diào)速，使系統(tǒng)快速性、可控性、經(jīng)濟(jì)性不斷提高。調(diào)速性能的不斷提高，使直流調(diào)速系統(tǒng)的應(yīng)用非常廣泛。在工業(yè)生產(chǎn)中,需要高性能速度控制的電力拖動(dòng)場(chǎng)合,直流調(diào)速系統(tǒng),特別是雙閉環(huán)直流調(diào)速系統(tǒng)發(fā)揮著極為重要的作用。轉(zhuǎn)速、電流雙閉環(huán)調(diào)速系統(tǒng)是20世紀(jì)60年代在國(guó)外出現(xiàn)的一種新型調(diào)速系統(tǒng)。70年代以來, 在我國(guó)的冶金、機(jī)械、制造以及印染工業(yè)等領(lǐng)域得到日益廣泛的應(yīng)用。雙閉環(huán)調(diào)速系

8、統(tǒng)是由單閉環(huán)自動(dòng)調(diào)速系統(tǒng)發(fā)展而來的。它通過轉(zhuǎn)速和電流兩個(gè)調(diào)節(jié)器分別引入轉(zhuǎn)速負(fù)反饋和電流負(fù)反饋，并構(gòu)成雙閉環(huán)系統(tǒng)。從而有效的改善電機(jī)性能。 本設(shè)計(jì)主要采用三相全控橋式整流電路對(duì)直流電機(jī)供電，并通過工程設(shè)計(jì)法對(duì)轉(zhuǎn)速調(diào)節(jié)器和電流調(diào)節(jié)器相關(guān)參數(shù)進(jìn)行計(jì)算以達(dá)到對(duì)轉(zhuǎn)速電流雙閉環(huán)支流調(diào)速系統(tǒng)的整體實(shí)現(xiàn)。3系統(tǒng)工作原理該系統(tǒng)主要由主開關(guān)，電機(jī)勵(lì)磁電路，晶閘管調(diào)速控制電路（包括 轉(zhuǎn)速表電路），整流濾波電路，平波電抗器放電電路，能耗制動(dòng)電路，整個(gè)系統(tǒng)采用閉環(huán)PI調(diào)節(jié)器控制的實(shí)現(xiàn)。當(dāng)主開關(guān)閉合，這單相交流獲得小的脈沖持續(xù)電流通過晶閘管調(diào)速控制電路的控制，和整流橋，為電機(jī)的濾波及平波電抗器，并在同一時(shí)間，通過整流勵(lì)磁

9、電路，交流使電機(jī)獲得激勵(lì)去開始工作。在調(diào)節(jié)觸發(fā)電路的速度設(shè)置電位器RP1由PIC16F877減少時(shí)，AN1輸入電壓下降使輸出控制的角度，和晶閘管隨流角，和主電路提高輸出電壓，和電機(jī)轉(zhuǎn)速增加，增大和測(cè)速電路的輸出電壓，和電機(jī)穩(wěn)定運(yùn)行在設(shè)定的速度范圍通過PI調(diào)節(jié)器的功能。4在系統(tǒng)各部分電路的設(shè)計(jì)4.1主電路的設(shè)計(jì)對(duì)電路中的各種成分的參數(shù)設(shè)置，如圖3所示。按下啟動(dòng)按鈕開關(guān)SW，使接觸器KM和KM回路，常開觸點(diǎn)閉合，其常閉觸點(diǎn)打開，并啟動(dòng)按鈕自鎖，主電路連接，與晶閘管調(diào)速電路通過改變雙向晶閘管的控制角控制的交流輸出，并通過橋梁得到直流整流和濾波，同時(shí)，電機(jī)通過整流勵(lì)磁電路獲得激勵(lì)開始工作。限制直流脈動(dòng)

10、，在電路中連接平波電抗器，和電阻R3提供放電回路平波電抗器在主電路突然斷了。加快制動(dòng)，能耗制動(dòng)是采用的設(shè)備，和制動(dòng)部分由電阻R4和主電路接觸器的常閉觸點(diǎn)。電動(dòng)機(jī)的勵(lì)磁是由單一的整流電路供電，并防止無法控制的高速事故通過電機(jī)的勵(lì)磁損耗引起的，在激勵(lì)電路中，串聯(lián)電流繼電器KA，和動(dòng)作電流可以通過調(diào)節(jié)電位器RP。4.2晶閘管觸發(fā)電路的設(shè)計(jì)在主電路中的A點(diǎn)和B點(diǎn)的電壓變?yōu)?0V通過變壓器，然后整流，約100小時(shí)半的信號(hào)發(fā)生在這兩個(gè)點(diǎn)，并與NPN三極管通過信號(hào)分壓R6和R7的放大，在三極管集電極產(chǎn)生過零脈沖，并捕獲零通道脈沖上升沿的CCP1模塊和注意發(fā)生第一時(shí)間，趕過零脈沖下降的邊緣，和兩者之間的時(shí)間差

11、為零的脈沖寬度，和值的一半是中點(diǎn)的脈沖，通過捕捉模式，我們可以準(zhǔn)確地獲得實(shí)際的過零點(diǎn)的交流，并在同時(shí)，我們可以利用ADC的模擬/數(shù)字轉(zhuǎn)換模塊將PIC16F877引腳的模擬電壓RA1 / AN1所設(shè)定的晶閘管控制的角度值（設(shè)定電機(jī)的轉(zhuǎn)速值），改變?cè)O(shè)定值電位器RP1和相應(yīng)地改變?cè)O(shè)置的晶閘管控制角的值，并輸出值轉(zhuǎn)速表電路由銷RA1/AN1 PIC16F877的輸入，和值作為速度反饋值通過A/D轉(zhuǎn)換。在單片機(jī)系統(tǒng)的振蕩頻率為4MHz，并根據(jù)特征PIC16F877訂貨周期，晶閘管控制角的分辨率是四分之一單片機(jī)振蕩的倒數(shù)1的頻率，即，在電力10ms的半波時(shí)間，控制角可以達(dá)到10000的步驟，完全實(shí)現(xiàn)電動(dòng)機(jī)

12、的無級(jí)平滑控制。4.3測(cè)速電路設(shè)計(jì)轉(zhuǎn)速表電路由光學(xué)編碼盤吸積與電機(jī)轉(zhuǎn)子和電脈沖放大整形電路。電脈沖頻率固定的比例與電動(dòng)機(jī)的轉(zhuǎn)速，和通過放大整形，由光學(xué)碼盤輸出電脈沖從引腳RC0 /T1CK1輸入PIC16F877作為標(biāo)準(zhǔn)的TTL電平，由計(jì)數(shù)TMR1計(jì)數(shù)器計(jì)算轉(zhuǎn)速，并比較與預(yù)設(shè)轉(zhuǎn)速和轉(zhuǎn)速得到差值，與PIC16F877單片機(jī)實(shí)現(xiàn)PI操作這種差異的價(jià)值得到增加的控制，并將晶閘管的控制角來改變有效CCP2電機(jī)的兩個(gè)端口的電壓，從而控制轉(zhuǎn)速。5.結(jié)論本次研究的課題直流電機(jī)雙閉環(huán)調(diào)速系統(tǒng)的動(dòng)態(tài)特性研究與仿真，是基于工程設(shè)計(jì)的方法，即用工程設(shè)計(jì)方法設(shè)計(jì)直流電動(dòng)機(jī)轉(zhuǎn)速、電流雙閉環(huán)調(diào)速系統(tǒng)。根據(jù)直流電機(jī)的基本方

13、程建立調(diào)速系統(tǒng)的數(shù)學(xué)模型，給出動(dòng)態(tài)結(jié)構(gòu)框圖，并用MATLAB搭建設(shè)仿真模型，進(jìn)行相關(guān)參數(shù)的調(diào)試與仿真，對(duì)仿真結(jié)果進(jìn)行分析、研究，驗(yàn)證控制方案的合理性。此次研究雖最終得到了滿意的結(jié)果，但在進(jìn)行系統(tǒng)仿真時(shí)也遇到了不少問題，主要原因在于系統(tǒng)建模與參數(shù)調(diào)試時(shí)沒有技巧?，F(xiàn)在我把本次仿真中獲得的一些技巧作個(gè)簡(jiǎn)單的總結(jié)：(1) 系統(tǒng)建模時(shí)，要分為主電路和控制電路分別進(jìn)行。(2) 在參數(shù)設(shè)置時(shí)，晶閘管整流橋和6脈沖觸發(fā)器按仿真需要選擇合適的參數(shù)，平波電抗器和直流電動(dòng)機(jī)中應(yīng)代入實(shí)際計(jì)算值，沒有相關(guān)要求的參數(shù)取默認(rèn)值即可。(3) 仿真時(shí)間的選擇按實(shí)際情況而定，以出現(xiàn)完整的波形為前提。(4) 調(diào)節(jié)器和反饋參數(shù)按計(jì)算

14、結(jié)果代入。(5) 若雙閉環(huán)仿真中出現(xiàn)問題，可以在開環(huán)的基礎(chǔ)上，一步一步增加反饋環(huán)節(jié)，調(diào)節(jié)環(huán)節(jié)和限幅環(huán)節(jié)，不斷調(diào)試，最終完成雙閉環(huán)的仿真。(6) 參數(shù)調(diào)試時(shí)，我們還應(yīng)耐心觀察，認(rèn)真分析，及時(shí)比較，不斷優(yōu)化系統(tǒng)。此次研究結(jié)果表明，直流電動(dòng)機(jī)雙閉環(huán)調(diào)速系統(tǒng)可以在給定調(diào)速范圍內(nèi)實(shí)現(xiàn)無靜差平滑調(diào)速。由于其超調(diào)量較小，系統(tǒng)具有較好的穩(wěn)定性、較高的穩(wěn)態(tài)精度以及優(yōu)良的動(dòng)態(tài)性能，這不僅為直流調(diào)速實(shí)驗(yàn)提供了理論依據(jù)，也為其它調(diào)速系統(tǒng)的研究打牢了理論基礎(chǔ)。但是其快速性要稍微差一點(diǎn)，這有待于以后繼續(xù)研究。Double closed loop dc motor speed control system research

15、1. An overview of theDc motor has good starting and brake performance, adaptable to achieve smooth speed regulation in large scale, and dc speed regulating system in theory and practice are more mature, is the basis of the study other speed regulation system. And MATLAB software to dc speed regulati

16、ng system in a virtual environment of simulation research, not only easy to use, also greatly reduces the cost of research.Is described in this paper, the basic principle of the dc motor and speed control principle, this paper introduces the dc motor open loop and double closed-loop speed control sy

17、stem composition and the static and dynamic characteristics, and according to the basic equation of the construction of dc motor made the mathematical model of speed control system, dynamic structure diagram are given, with engineering design method of dc motor double closed loop speed control syste

18、m is designed. Finally, the MATLAB simulation software to build the simulation model of speed control system for the study of the simulation.Through the dynamic characteristics of a dc motor double closed loop speed regulation system in the research and simulation, can see clearly that dc motor doub

19、le closed loop speed regulation system has good dynamic performance, can be in the given speed range, realize the astatic smooth speed regulation,For the dc motor speed control system hardware experiments provide a theoretical basis.2. The double closed loop dc governing system research backgroundDc

20、 speed control is the modern electric drive automatic control system in the development of an earlier technology. In the 1960 s, with the emergence of thyristor, the combination of modern power electronics and control theory, computer promotes the prosperity of the electric drive control technology

21、research and application. Thyristor - dc motor speed control system for modern industry provides a highly efficient, high performance power. Although at present the rapid development of ac speed regulation, the more hasten is mature ac (alternating current) technique, and the efficiency of ac motor

22、and maintainability, the ac speed regulation is widely welcomed by users. But the dc motor speed control system, with its excellent speed regulating performance still has broad market, and based on feedback control theory of dc speed regulation principle is the basis for the control of ac speed regu

23、lation. Now the dc and ac speed regulating device is digital, using chips and software have different features, but the basic control principle has its generality.There is a big risk for those in the actual process of debugging or experimental system of expensive, generally does not allow experiment

24、s to design a good system directly. Through experimental studies, however, do not is not to design a good system directly on the actual production. So you must be on the simulation experiment research. , of course, in some cases can construct a set of device physics experiment, but this method is ve

25、ry time consuming and cost high, and in some cases, physical simulation is almost impossible. In recent years, with the rapid development of computer, USES the computer control system for mathematical simulation method has been adopted by people.But for a long time, the simulation in the field of re

26、search is focused on the establishment of simulation model is a process, namely the system model is established to design an algorithm. To make the system model for the computer, and then compiled into a computer program, and run on the computer. Thus produced a variety of simulation algorithms and

27、simulation software.Due to the model establishment and simulation study is less, so modeling often takes a long time, at the same time, the analysis of simulation results must rely on experts, and decision makers is a lack of direct guidance, thus greatly hindered the popularization and application

28、of simulation technology.Provide dynamic simulation tool Simulink in MATLAB, is the most powerful in many simulation software, one of the most outstanding, the most easy to use. It effectively solves the above problems in simulation technology. In Simulink, the modeling of the system will become ver

29、y simple, and the simulation process is interactive, so you can casually change the simulation parameters, and can immediately get the modified results. In addition, the use of MATLAB in various analysis tools, also can be the result of the simulation analysis, and visualization.Simulink can go beyo

30、nd the ideal linear model to explore more realistic models of nonlinear problem, such as friction and air resistance in the real world, the gear meshing and other natural phenomena; Simulation to the macroscopic objects, it can be to micro molecules and atoms, it can be the type of object modeling a

31、nd simulation is extensive, can is a mechanical, electronic and other real entity, also can be the ideal system, but the simulation of the complexity of the dynamic system but can small, can be continuous, discrete or hybrid. Simulink can make your computer into a lab, use it for all kinds of existi

32、ng in reality, does not exist, or even opposite system modeling and simulation.Since the 70 s, both at home and abroad in the field of electric drive extensively adopted "thyristor dc motor speed regulation technology" (hereinafter referred to as the V - M speed control system). Although t

33、oday's power semiconductor converter technology has been the development by leaps and bounds, but V - M system in industrial production are still occupies a considerable proportion. In the process of engineering design and theoretical study, to be exposed to a lot of speed control system analysi

34、s, synthesis and design problem. Traditional research methods mainly include analytical method, experimental method and simulation experiment, in which they have their respective advantages in the former two methods at the same time it still has different limitations. Along with the development of p

35、roduction technology, the electrical driving and braking, and reversing and speed control precision, speed range, static characteristic and dynamic response, etc, put forward the higher request, this requires extensive use of speed control system. As a result of the dc motor speed control and torque

36、 control performance is good, since the 1930 s, started using dc speed regulating system. Its development process is this: by the rotation of the earliest development of converter unit control for enlarger, magnetic amplifier control; Further, in the stillness of the thyristor converter device and a

37、nalog controller realize dc speed regulation; Later, with controlled rectifier and high-power transistors of PWM control circuit to realize the digital dc speed control, make the system quickness, controllability and economy enhances unceasingly. The continuous improvement of speed regulating perfor

38、mance, make the dc speed regulation system has a very wide range of applications.In industrial production, the need of high performance speed control of electric drive occasion, the dc speed regulation system, especially the double closed loop dc speed control system play an extremely important role

39、. Speed and current double closed-loop speed control system is in the 1960 s of a new type of speed control system in foreign countries. Since the 70 s, in our country's metallurgical, mechanical, manufacturing and printing and dyeing industry is increasingly widely used. Double closed loop spee

40、d control system is developed by the automatic single closed-loop speed control system. It introduced through two speed and current regulator respectively speed negative feedback and current feedback, and constitute the double closed loop system. Effectively improve the motor performance. This desig

41、n mainly adopts three-phase fully-controlled bridge rectifier circuit of dc motor power supply, and through the engineering design method for speed regulator and current regulator parameters calculation in order to achieve the speed of current double closed loop speed regulation system of a tributar

42、y of the overall implementation.3 working principle of the systemThe system is mainly composed of the main switch, the motor excitation circuit, thyristor speed control circuit (including tachometer circuit), rectifier filter circuit, flat wave reactor discharge circuit, energy consumption braking c

43、ircuit, the realization of the whole system is controlled by closed-loop PI regulator. When the main switch is closed, the small pulse current in single-phase ac gain control of thyristor speed control circuit, and the rectifier bridge, the filter for the generator and the flat wave reactor, and at

44、the same time, through the rectifier excitation circuit, ac motor inspired to begin to work. In regulating the speed of the trigger circuit potentiometer RP1 by PIC16F877 to decline, the decline of AN1 input voltage output control point of view, and the brake pipe flow Angle, and the main circuit to

45、 improve the output voltage, and the motor speed increase, increase and speed measuring circuit of the output voltage, and motor in setting speed, stable operation range by the function of the PI regulator.4. All parts of the system design of the circuit4.1 the design of the main circuitFor componen

46、ts in the circuit parameter Settings, as shown in figure 3. Press the start button switch SW, make the contactor of KM and KM circuit, the normally open contact closure, the normally closed contact is opened, and start button self-locking, main circuit connection, and thyristor speed control circuit

47、 by changing the two-way thyristor control Angle control of ac output, and dc rectifier and filter is obtained by a bridge, at the same time, the motor through rectifier excitation circuit have incentives to work. Limit the dc pulse in the circuit connection flat wave reactor, and the resistance R3

48、provide discharge circuit flat wave reactor snapped in the main circuit. To speed up the braking, energy consumption braking is to use the equipment, and brake parts by the resistor R4 and normally closed contact of main circuit contactor.The excitation of the motor is from single power rectifier ci

49、rcuit, and to prevent uncontrollable high speed accident caused by motor excitation loss, in the drive circuit, in series current relay KA, and current action can by adjusting the potentiometer RP.4.2 the design of the thyristor trigger circuitPoint A and point B in the main circuit of voltage to 20

50、 v through A transformer, then rectifier, about 100 and A half hours of signal occurred in these two points, and through the signal points with NPN R6 and R7 amplification, the triode had A zero pulse collector, and capture zero channel pulse rising along the CCP1 module and pay attention to happen

51、the first time, catch the zero pulse falling edge, and the time difference between the two is zero pulse width, and the value is half of the midpoint of pulse, by capturing mode, we can accurately obtain the actual passing zero communication, and at the same time, we can use the ADC analog/digital c

52、onversion module will analog voltage of PIC16F877 pin RA1 / AN1 set by the Angle of the thyristor control value (set motor speed value), change the set point potentiometer RP1 and change accordingly set the value of the thyristor control Angle, and the output value tachometer circuit by pin RA1 / AN

53、1 PIC16F877 input, and values as feedback speed by A/D conversion. In the single-chip microcomputer system oscillation frequency is 4 MHZ, and according to the characteristics of PIC16F877 ordering cycle, the resolution of the thyristor control Angle is a quarter of a single chip microcomputer frequ

54、ency of oscillation of the reciprocal of 1 mu, i.e., in the power of 10 ms half wave time, control Angle can reach 10000 steps, fully realize the stepless smooth control of the motor.4.3 speed measuring circuit designTachometer circuit encoded by optical disk accretion and the motor rotor and electr

55、ical pulse shaping circuit. Electrical pulse frequency fixed ratio and the rotational speed of the motor, and through the amplification plastic, by the optical encoder output electrical impulses from pin RC0 / T1CK1 input PIC16F877 as standard TTL level, by counting TMR1 counter calculation speed, a

56、nd compare with the preset rotating speed and rotating speed difference, the difference with PIC16F877 singlechip microcomputer PI operation control value increases, and the thyristor control Angle to change effective CCP2 motor voltage of two ports, so as to control speed.5 ConclusionThe study of t

57、he subject - dc motor double closed loop speed regulation system dynamic characteristic research and simulation, is based on the engineering design method of engineering design method to design dc motor speed and current double closed-loop speed control system. According to the basic equation for dc motor speed control system of mathematic model, the dynamic struc