发布时间 : 星期日 文章机电专业外文翻译----机电驱动综合设计更新完毕开始阅读8809ef8b5022aaea988f0f15
图13. 一个平衡的三相终端的22极电机短路电流
七．总结
该设计是挑战用一个电机控制直接控制而没有一个中间齿轮箱。一种靠直接驱动的扰流器正在开发中。结果表明，直接驱动提高了可靠性，减轻重量，并提供一个更紧凑的系统。误差允许范围大，可通过适当的机械设计及适当控制事故发生满足要求。
集中的缠绕机在提供扭矩密度和误差范围方面有诸多优势，事实证明是一个很合适的选择。为了减少误差，电机相间交替绕组提供的的物理隔离是必不可少的。但在重载或相位出错的情况下，这类电机会有较高的定子绕组谐波且可执行性差。
参考文献
[1] Patrick W Wheeler, Lee Empringham, Maurice Apap, Liliana de Lilo, J. C. Clare, K. J. Bradley. A Matrix Converter Motor Drive for an Aircraft Actuation System in: IEEE EPE2003, 2003,pp 472~381.
[2] A.S. Goodman, K.J. Bradley, P.W. Wheeler. Evaluation of the Single Sided Matrix Converter Driven Switched Reluctance Motor in: the 39th IEEE IAS Conference, 2004
[3] Mecrow, B.C.; Jack, A.G.; Atkinson, D.J.; Green, S.R.; Atkinson, G.J.; King, A.; Green, B.; Design and testing of a four-phase fault-tolerant permanent-magnet machine for an engine fuel pump Energy Conversion, IEEE Transactions on Volume 19, Issue 4, Dec. 2004 Page(s):671 - 678
[4] Haylock, J.A.; Mecrow, B.C.; Jack, A.G.; Atkinson, D.J.; Operation of fault tolerant machines with winding failures; Energy Conversion, IEEE Transactions on Volume 14, Issue 4, Dec. 1999 Page(s):1490 - 1495
[5] Gerada, C.; Bradley, K.J.; Sumner, M.; Wheeler, P.; Pickering, S.; Clare, J.; Whitley, C.; Towers, G.; The implications of winding faults in induction motor drives; Industry Applications Conference, 2004. 39th IAS Annual Meeting. Conference Record of the 2004 IEEE Volume 4, 3-7 Oct. 2004 Page(s):2506 - 2513 vol.4
Integrated Machine design for Electro Mechanical Actuation
Abstract— This paper describes work on an integrated electro mechanical actuator intended as a technology demonstrator to satisfy future aircraft requirements for a typical mid spoiler actuation system for a large civil aircraft. The design and analysis of a directly coupled motor to a roller screw without any intermediate gear box will be detailed in this paper. The main goals of the design are a high level of actuator integration in order to minimize weight and volume, fault tolerance and highreliability.
I. INTRODUCTION
As the modern aircraft heads towards a more electric based generation and distribution system there is an increased drive towards having electrical loads. One of the most researched areas are primary and secondary flight actuation surfaces. Using an electrical supplied actuator gives the distinct advantage of not needing a hydraulic supply whith all its associated disadvantages.
In general electrical supplied actuators can be divided into EHAs (Electro Hydraulic Actuators) and EMAs (Electro Mechanical Actuators). EHAs consist of a variable speed pump supplying a local hydraulic actuation system whilst EMAs are often just a variable speed electrical motor drive coupled to a ball or roller screw through a gearbox. Whilst EMAs offer a total leakage free solution, EHAs are often preferred to EMAs in safety critical applications due to the problem of possible mechanical jams in EMAs.
The jamming issue with EMAs is currently being researched from both the material surface properties point of view as well as finding safe and effective methods to disengage a jammed EMA from the flight surface.
Electrical machines are an enabling technology in reducing the probability of an EMA jamming. This work will look at the compromises and issues with driving a roller screw directly coupled to an electrical machine, rather than driven through a gear box. A foreseeable advantage is the reduced jamming probability and the increased reliability of the actuation system. On the other hand one can argue that a directly coupled motor will lead to a larger motor as motor size is roughly proportional to torque and thus having a heavier and bigger actuator. This work looks at a novel integrated machine and roller screw design directly coupled to each other improving the reliability of the actuator and at the same time reaching the same power
densities of the geared system.
EMAs for flight surfaces usually consist of a high speed motor coupled through a gearbox to a ball or roller screw. For a given power, the higher the speed of the machine the smaller will be the motor, however the greater the gear ratio and hence the size of the gearbox.
Another way of achieving a high power density is to use a high pole number machine. The active rotor magnetic material decreases as the pole number goes up leaving a hollow space in the centre of the machine. The idea is to integrate the ball or roller screw nut inside the rotor and have a high pole numbered machine driving it.
II. MACHINE DESIGN ISSUES FOR AEROSPACE APPLICATIONS The general requirements for any aircraft actuation drive are minimum size, weight and costs to reach the necessary performance requirements in addition to a degree of fault tolerance and reliability depending on the flight surface in consideration and the number of backup actuators opted for.
Fault tolerance is best achieved by having redundant drive components. This may either be achieved by duplicating or triplicating the whole drive or otherwise have independent redundant systems the number of duplicates depending on the reliability of the particular component. It is however important in any choice of fault tolerant topology to have each system isolated from the others so as to minimize the possibility of common failure. This is finally a cost and size optimization exercise depending heavily on the actuator function. From an electrical drive point of view it is often argued that the electrical machine itself can be made fault tolerant up to a certain degree not needing a duplicate one. This is usually achived by designing machines to operate with short circuit and open circuit faults. This is done by using multi phase machines and ensuring that the phase windings and the power electronics supplying them are magnetically, electrically and physically decoupled. The main disadvantage of using multiphase machines is the duplication of the power and control electronics, which have a low reliability.
Another compromise to make is on the type of machine to use. Sinusoidally excited machines are generally preferred if the machine is to be fed from an AC bus, this being mainly due to the compatibility with matrix converters which give distinct advantages in case of an AC distribution system, mainly due to the elimination of the DC link and the unreliable electrolytic capacitors [1,2]. Sinusoidally supplied machines are however seen as not being fault tolerant in their more traditional form due to the high magnetic and physical coupling of their phase windings. Non-sinusoidally fed machines are potentially more fault tolerant but are not practical to be used with a matrix converter due to the resulting supply current distortion. Machines which are sinusoidally supplied but have concentrated coils giving the required levels of phase isolation are seen as a good solution for such applications [3,4]. A) Geared vs. Direct Drive Systems