【正文】 idly deployed in service if they promise significant performance improvements. This was the case for the early choppers supplying seriesconnected DC traction motors, separatelyexcited DC motors, synchronous AC motors and drives (as used on the first generations of TGVs) and for the various generations of asynchronous (squirrelcage) threephase drives. As technology moved forward, traction drives became more efficient and more controllable, allowing better use of available adhesion while reducing energy consumption. The permanentmag synchronous machine, with its associated control electronics, represents the latest such advance in traction technology. Millions of small PMSMs are already being used in the transmissions of hybrid cars, thanks to their low mass and good controllability. Larger machines offer a similar potential to enhance the overall performance of the railway traction package. The technology is now beginning to be introduced into a variety of new rolling stock, 大連交通大學 2020 屆本科生畢業(yè)設計（論文）外文翻譯 but the integration of PMSMs into traction packages presents some significant technical challenges which must be overe. Fundamental requirements Petrol and diesel engines for automotive applications generally require plex gearboxes to allow the prime mover to operate in the optimum speed band. By contrast, electric motors for rail traction are expected to operate effectively and efficiently over the entire speed range, allowing a permanent coupling to the axles and wheels, either directly or via a single ratio gearbox. This mechanically elegant solution results in highly reliable drives which need relatively little maintenance. Thus the first requirement placed on the design of traction motors is the ability to provide torque or tractive effort over a wide speed range, such as from 0 to 320 km/h. Whilst it is essential for the traction motor to operate reliably, it is equally important from the driver39。 because of machine limitations. Torque control At low speeds, the motor can in theory provide a torque that is greater than that which can be transmitted by means of the adhesion available at the wheelrail interface. However, this would overload the motor beyond the normally accepted level and must therefore be avoided either by driver action or an electronic control system. Early DC traction drives were controlled by adjusting the supply voltage using series resistances and by changing the motor group configuration. Today, both DC mutator motors and classic synchronous and asynchronous AC motors are controlled electronically, by varying either the voltage or the voltage and frequency. Modern power drives with relatively simple algorithms achieve very good control of tractive effort throughout the speed range. Power control of permanentmag synchronous machines can easily deliver good performance in the constanttorque region, but this needs plex algorithms to control the machine in the constant power region. AC and DC motors, as well as PMSMs, fundamentally rely on the same physics to generate accelerating and braking torques. Hence the control strategies are similar to some extent. In all types of machines, the torque is created through the interaction between two magic fields. To generate a torque, there must be an appropriate electrical angle (ideally 90176。dl1, but these can lead to a reduction in the accuracy of control. The magic flux is temperaturedependent in that the field strength reduces by about 1% per 10K increase in rotor temperature. With PMSMs operating over a temperature range of 200K (40176。 在采用新技術 方面 ，鐵路運營商往往被視為 是 保守的 ，但 鐵路牽引系統(tǒng)的設計者和制造商 傾向于 利用最新的驅動技術， 如果這些技術有望帶來顯著的 性能改進 ，就會很快地被應用。相比之下，用于軌道牽引的電動馬達 被期望 在整個速度范圍內 能夠 有效和高效地 運作 ，使一個永久耦合的車軸和車輪，直接地或通過一個單一的比變速箱。圖 1 示一個典型的驅動系統(tǒng)的 TE 曲線，以及與 之 相關聯(lián)的鐵路列車或車輛 的 阻力曲線。成反比。因此，控制策略在一定程度上相似。在一系列連接的機器中，定子和轉子 線圈 （圖 3） 上有 相同的電流流過，而 在 一個單獨勵磁機 中，電樞和定子 被 獨立地控制（圖 4）。這種差異可以表示為轉差頻率或百分比滑移。 由電機提供或吸收的轉矩 被認為是 磁通和電流 相互作用的結果 。 當電源頻率 增加， 而 電源電壓保持恒定 時， 感應機 的 磁場削弱 會 自 發(fā)進行 。通常情況下， PM 機器定子完全密封 ，并由 傳熱流體的裝置 進行 冷卻，從而 產生了 潛在的更加可靠的驅動器。 在定子繞組中 ， 這些額外的電流會導致銅損 。如 同 開發(fā)的 Schr246。然而，越來越多的現代牽引系統(tǒng)使用單獨控制 的 電機以 優(yōu)化性能， 這是缺乏考慮的 。向定子繞組供給的控制也更復雜，因為多個反饋回路和信號轉換是必需的（圖 8）。 紐鮑爾 TraktionsSYSTEME 奧地利，和科林 一個很好的例子是在本文開頭提到的使用永磁同步電機 V150 的 小火車。 大連交通大學 2020 屆本科生畢業(yè)設計（論文）外文翻譯 類似 地，無負荷運行 過程 中，當列車滑行 時 ，永久磁鐵轉子 會 繼續(xù) 減少定子鐵芯 中的 感應電流。C 的溫度范圍內的最大允許160176。 （視場角）之間的準確性 是必要的 。