【正文】 大連交通大學(xué) 2020 屆本科生畢業(yè)設(shè)計(jì)（論文）外文翻譯 外文原文 The Rise Of The Permanentmag TractioMotor Technology offering benefits in terms of mass, size and energy consumption, the permanentmag synchronous machine is increasingly being adopted for traction drives, despite the need for plex control systems and potential failure modes. In the past couple of years, many of the bids for new rolling stock placed with major international suppliers have proposed the use of permanentmag synchronous traction motors, which are smaller and lighter than the threephase induction motors that have dominated the market in recent times. Permanentmag motors first came to prominence with the use of two powered bogies from Alstom39。s AGV in the V150 trainset which broke the world speed record on April 3 2020, but they have subsequently been used in a variety of applications, ranging from the CitadisDualis tramtrain to SBB39。s Twindexx doubledeck intercity trainsets (Table I). Although railway operators are often viewed as conservative in the adoption of new technologies, the designers and manufacturers of rail traction systems tend to capitalise on the latest drive technologies, which are rapidly 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(xué) 2020 屆本科生畢業(yè)設(shè)計(jì)（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。s and railway operator39。s perspective that modern traction systems control the torque accurately and smoothly throughout the speed range. Excellent torque control results in optimum use of available adhesion between wheel and rail, along with smooth acceleration and the ability to cruise at a constant speed and to brake the train electrically (dynamic braking). Tractive effort, power and speed The torque produced in a traction motor is translated into a linear force at the wheelrail interface. This force, which causes the train to accelerate or brake dynamically, is normally referred to as the tractive effort. Fig 1 shows the TE curve of a typical drive system, together with the associated train or vehicle resistance curve. The TE curve intersects the resistance curve at the socalled balancing speed, that is, the theoretical maximum speed. Close to this speed, there is only a very small amount of tractive effort available to accelerate the train, as indicated by the red arrow in Fig 1. Fig 2 shows the power produced by the drive and the propulsion power required, which is the product of speed and tractive effort. Traction motors are generally designed to match a particular duty. The motor must produce the required full torque at zero speed and