【正文】 定子磁鏈的 ui 模型 在計算過程中唯一所需要了解的電動機參數(shù)是易于確定的定子電阻 .定子電壓 u,和定子電流 i 同樣也是易于確定的物理量，它們能以足夠的精度被檢測出來 .ui 模型只有在被積分的差值較大時才能提供正確的結(jié)果。途中 VSI表示電壓源逆變器，它能提供 8個開關(guān)電壓矢量。一個電壓型三相逆變器的拓?fù)浣Y(jié) 構(gòu)如圖 所示。當(dāng)定子磁鏈空間矢量 ，在圖 24所示位置時，其頂點在邊 上，如果逆變器加到定子的電壓空間矢量為 (011)，根據(jù)式 (25)中定子電壓和定子磁鏈之間的積分關(guān)系，定子磁鏈空間矢量的頂點將沿著 邊的軌跡，朝著電壓空間矢量 (011)作用的方向運動，到達(dá) 和的交點時，這時如給逆變器加上電壓空 間矢量 (001)，則定子磁鏈空間矢量 ，頂點會按照與 (001)平行的方向，沿著邊 的軌跡運動。在控制算法中，電機參數(shù)是必不可少的量。它的主要思想是利用滯環(huán)比較器實現(xiàn)對定子磁鏈和電磁轉(zhuǎn)矩的分別控制，結(jié)合扇區(qū)信息，通過一個開關(guān)表有選擇地輸出基本空間電壓矢量，來控制電磁轉(zhuǎn)矩和定子磁鏈按要求快速變化。交流異步感應(yīng)電動機具有結(jié)構(gòu)簡單、運行穩(wěn)定、成本低廉以及維護(hù)簡單的特點，在其中占據(jù)了絕大多數(shù)。三相異步電機的直接轉(zhuǎn)矩控制技術(shù)是繼矢量控制技術(shù)之后發(fā)展起來的一種新型、高性能變頻調(diào)速技術(shù)。 關(guān)鍵詞： 異步電機 、直接轉(zhuǎn)矩 控制 、 系統(tǒng)仿真 、 磁鏈計算 三相異步電機直接轉(zhuǎn)矩控制研究 2 Abstract: For threephase asynchronous motor direct torque control (DTC) is a high performance frequency control. The threephase asynchronous motor direct torque control following the vector control technology developed a new, highperformance frequency control technology. Use of space vector analysis method, directly in the stator coordinate system and control the torque of the AC motor stator flux orientation control of torque and flux hysteresis PWM signal directly to the inverter switching state the optimal control, in order to obtain high dynamic performance of the system. Direct Torque Control with fast torque response, the control structure is simple, easy to implement fully digital features, are widely used. With economic development, the use of highperformance AC speed gradually to replace higherpriced DC speed in many areas is a trend. Direct Torque Control is the greatest potential for a highperformance AC variable speed, and the control method is very suitable for alldigital, so its indepth study has a good practical significance. 1985 German scholar Depenbrock and Japanese scholars Takahashi have put forward the idea of induction motor direct torque control (DTC). Direct Torque Control technology was born, novel control their own thoughts, concise system structure, excellent static performance by the general concern and has been a rapid development. The DTC study has been made a lot of progress, but it also in theory and practice is not mature enough, such as lowspeed performance, torque ripple, limiting the speed range of the system. Threephase induction motor speed control system of this thesis direct torque control scheme. Related to the multidisciplinary field of motor drives, power electronics, automatic control theory, the direct torque control system, including torque calculation, flux, torque, flux linkage hysteresis regulator and speed PI regulator, mainly includes the following four parts: First part of introducing the subject of research background and domestic research status quo. The second part of the establishment of a mathematical model of the threephase 三相異步電機直接轉(zhuǎn)矩控制研究 3 asynchronous motor, clear basic principle of direct torque control. The third part, a detailed analysis of the position of the various parts of the direct torque control system. The fourth part of the simulation using MATLABSIMULINK tool for the design of threephase asynchronous motor direct torque control system and dynamic analysis of simulation results, static control effect. Keywords: Asynchronous motors, DTC, System Simulation, MTBLAB, Flux calculation 三相異步電機直接轉(zhuǎn)矩控制研究 4 1 緒論 課題研究的背景、目的及其意義 在我們的日常生活中，電機傳動設(shè)備已經(jīng)深入到社會生活的各個領(lǐng)域。 (3)基于磁鏈和轉(zhuǎn)矩直接控制的矢量控制技術(shù)，也稱直接轉(zhuǎn)矩控制。因此，研究高性能的直接轉(zhuǎn)矩控制算法是大勢所趨，非常必要。移項并積分可得定子磁鏈公式 ： ()()s s s ss s s su R i dtu R i dt? ? ?? ? ??? ? ???? ? ????? (22) 轉(zhuǎn)矩公式： ()e p s s s sT n i i? ? ? ?? ? ? ? (23) 式中 —— 電磁轉(zhuǎn)矩（ N ） —— 電機極對數(shù) —— 磁通角（ rad） 電機運動公式 1 weL ptdT T J nd?? (24) 式中 —— 負(fù)載轉(zhuǎn)矩（ N ） 三相異步電機直接轉(zhuǎn)矩控制研究 8 J —— 轉(zhuǎn)動慣量（ kg ） 上述三式就是三相交流異步電機在兩相靜止坐標(biāo)系下的電壓公式、磁鏈公式以及轉(zhuǎn)矩公式，它們共同組成了電機的數(shù)學(xué)模型，這就是本文接下來進(jìn)行控 制系統(tǒng)分析和研究的基礎(chǔ)。而轉(zhuǎn)子磁鏈不直接跟隨定子磁鏈，定子磁鏈的旋轉(zhuǎn)速度大于轉(zhuǎn)子磁鏈的旋轉(zhuǎn)速度，磁通角由 ( )增加到 ( )，相應(yīng)的轉(zhuǎn)矩增大。正因如此，雖然直接轉(zhuǎn)矩控制從理論提出到實際應(yīng)用都滯后于矢量控制，但由于該方法本身固有的優(yōu)勢，使直接轉(zhuǎn)矩控制的理論研究和技術(shù)開發(fā)越來越受到重視，進(jìn)展的步伐也越來越快。所以定子磁鏈的準(zhǔn)確觀測是異步電動機直接轉(zhuǎn)矩控制系統(tǒng)的重要組成部分，起著決定性作用。如圖 所示 : 三相異步電機直接轉(zhuǎn)矩控制研究 17 R SIIP IR SIIP IR rL σR rL σi s αi s α+? i+’Ψ s αΨ s β++++1L σ1L σ1L1L++Ψ r αΨ r αΨ r βΨ r βΨ s αΨ r α++++++i s β’i s βω 圖 un 模型 圖 29 中，電流調(diào)節(jié)“ PI”單元的作用是強迫電動機模型電流和實際的電動機電流相等 .如果電動機模型得到的電流 與實際測量到的電動機電流 不相等 .就會產(chǎn)生一個差值 送入到電流調(diào)節(jié)器的輸入端。以此類推，如圖中虛線箭頭所示，就保證了 s?的幅值一直被限定在希望的范圍內(nèi)。如此，逆變器只能在這個規(guī)則下一次選擇非零開關(guān)電壓矢量，在這種情況之下，既不能選擇零電壓開關(guān)矢量，又沒有辦法實現(xiàn)對定子磁鏈的調(diào)制，這樣的結(jié)果是定子磁鏈?zhǔn)噶康能壽E呈靈變形，而不是圓形。 綜上所述，直接轉(zhuǎn)矩控制在很大程度上克服了矢量控制的復(fù)雜性，它采用空間矢量的分析方法，直接在定子坐標(biāo)系下計算與控制交流電動機的轉(zhuǎn)矩，采用定子磁場定向，借助離散的兩 點式調(diào)節(jié)產(chǎn)生 PWM 信號，直接對逆變器的開關(guān)狀態(tài)進(jìn)行最佳控制，以獲得轉(zhuǎn)矩的高動態(tài)性能，是一種具有高動態(tài)性能的交流調(diào)速方法。另外 MATLAB和其他高級語言也具有良好的接口，可以很方便地與其他語言實現(xiàn)混合編程，這都進(jìn)一步拓寬了它的應(yīng)用范圍和使用領(lǐng)域。 (2)DTC 算法直接對定子磁鏈和電磁轉(zhuǎn)矩進(jìn)行控制，并采用了轉(zhuǎn)矩和磁鏈雙閉環(huán)的 控制策略，可以使得被控制量快速準(zhǔn)確地跟隨給定值變化，動態(tài)性能良好。接下來，本文根據(jù)逆變器的拓?fù)浣Y(jié)構(gòu)，引出了空間矢量的概念，介紹了 8 個基本的空間電壓矢量，并詳細(xì)介紹了基本空間電壓矢量對電機磁鏈和轉(zhuǎn)矩的影響作 用。 DSP 器件的進(jìn)一步發(fā)展也為 DTC 技術(shù)難題突破提供了可能。s about how he felt and I would like to speak to him first to find out what his experience was. 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