外文翻译电动汽车外转子定子PM无刷电机驱动器的比较.docx

1、外文翻译电动汽车外转子定子PM无刷电机驱动器的比较外文原文Comparison of Outer-Rotor Stator-Permanent-Magnet Brushless Motor Drives for Electric Vehicles K.T. Chau1, Senior member IEEE, Chunhua Liu1, and J.Z. Jiang2 1 Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China 2 Department

2、of Automation, Shanghai University, Shanghai, 200072, ChinaAbstractIn this paper, two emerging outer-rotor stator-permanent-magnet (PM) brushless motor drives, namely the doubly-salient PM motor drive and the PM hybrid brushless motor drive, are firstly quantitatively compared, which are particularl

3、y attractive for serving as in-wheel motor drives for electric vehicles. In order to enable a fair comparison, these two motor drives are designed with the same peripheral dimensions and based on the same outer-rotor 36/24-pole topology. By utilizing the circuit-field-torque time-stepping finite ele

4、ment method for analysis, their steady-state and transient performances are critically compared. Moreover, the cost analysis of these two machines is conducted to evaluate their cost effectiveness.Index Terms Electric vehicle, Finite element method, Machinedesign, Permanent-magnet motor drive. I. IN

5、TRODUCTIONIn recent years, permanent-magnet (PM) brushless motordrives have been widely used in electric vehicles (EVs) 1-2.The doubly-salient PM (DSPM) motor drive and PM hybridbrushless (PMHB) motor drive are two emerging stator-PMbrushless motor drives which offer high mechanical integrityand hig

6、h power density, hence suitable for EV applications 3.Their outer-rotor motor structures are particularly attractive fordirect driving of EVs, especially for serving as in-wheel motordrives for EVs 4. However, a quantitative comparison of thesewo motor drives is absent in literature. The purpose of

7、this paper is to newly compare two emergingouter-rotor stator-PM brushless motor drives, namely the DSPMand PMHB types. Based on the same peripheral dimensions,both motor drives are designed with the identical outer-rotor36/24-pole topology. By using the circuit-field-torquetime-stepping finite elem

8、ent method (CFT-TS-FEM) 5, thesteady-state and transient performances of both motor drives arecompared and analyzed. Moreover, the corresponding costeffectiveness will be revealed and discussed.Section II will introduce the motor drive systems and their configurations. In Section III, the design and

9、 cost effectiveness of two motor drives will be compared. Section IV will discuss the analysis approach of these two motor drives. The comparison of their performances will be given in Section V. Finally, a conclusion will be drawn in Section VI.II.SYSTEM CONFIGURATION AND OPERATION MODES Fig. 1 sho

10、ws the schemes of these two outer-rotor stator-PM motor drives when they serve as the in-wheel motor drives for EVs, especially for motorcycles. It can be seen that these in-wheel motor drives effectively utilize the outer-rotor nature and directly couple with the tire rims. So, these topologies can

11、 fully utilize the space and materials of the motor drives, hence greatly reducing the size and weight for EV applications. Fig. 1. Topologies of proposed in-wheel motor drives. (a) DSPM. (b) PMHBThe two motor drives configurations are shown in Figs. 2 and 3. It can be found that they have the simil

12、ar three-phase full bridge driver for the armature windings; while the difference is the H-bridge driver for the DC field windings of the PMHB motor drive. Hence, their operation principles are very similar, except that the controllable field current of the PMHB motor drive. For both motor drives, w

13、hen the air-gap flux linkage increases with the rotor angle, a positive current is applied to the armature windings, resulting in a positive torque. When the flux linkage decreases, a negative current is applied, also resulting in a positive torque. For the PMHB motor drive, it can accomplish online

14、 flux regulation by tuning the bidirectional DC field current.When these two motor drives act as in-wheel motor drives and are installed in the EVs, they operate at three modes within the speed range of 01000rpm, namely the starting, the cruising, and the charging.When the EV operates at the startin

15、g mode, it needs a high torque for launching or accelerating within a short time. For the DSPM motor drive, since its PM volume is much more than that of PMHB motor one, it can provide a sufficiently high torque for the EV starting. For the PMHB motor drive, the positive DC field current will be add

16、ed to produce the magnetic field together with the PM excited field, hence it also able to offer the high torque for the EV to overcome the starting resistance and the friction force on the road.When the EV runs downhill or works in braking condition, it works in the charging mode. In this mode, the

17、se two machines can play the role of electromechanical energy conversion, which recover or regenerate the braking energy to recharge the battery module. Furthermore, for the PMHB machine drive, it can fully utilize its flux controllable ability to maintain the constant output voltage for directly ch

18、arging the battery, which is more flexible than the DSPM machine drive. When the EV runs in the cruising mode or in the steady speed, these stator-PM motor drives will enter the constant-power region. This speed range usually covers 400rpm1000rpm for the DSPM in-wheel motor drive. But for the PMHB m

19、otor drive, it not only can effectively extend its operating speed range up to 4000rpm which is enough to cover the conventional speed range requirement, but also can regulate its magnetic field situation which can make the power module working at the optimal operation point. Fig. 2. Configuration o

20、f DSPM motor drives.Fig. 3. Configuration of PMHB motor drive.III. COMPARISON OF MOTOR DRIVES STRUCTURES AND FEATURESThe two stator-PM motor drives structures are shown in Figs. 2 and 3. It can be seen that they have the same peripheral dimensions and the identical outer rotor, as well as the same 3

21、6/24 pole and armature windings. The major difference is their stators and field excitations. The DSPM motor drive is simply excited by PMs, which is located in the stator. But for the PMHB motor drive, it has double-layer stator and double excitations. Its outer-layer stator accommodates the armatu

22、re windings, whereas its inner-layer stator contains PMs and DC field windings together to produce the magnetic field 6. Their similar structures achieve many advantages when they serve as the in-wheel motor drives for EVs. The outer-rotor nature can make the machine directly connect with the tire r

23、im, which totally eliminates the mechanical gear transmission and processes high mechanical integrity. Hence, it reduces the power loss, the system complication, and the total cost. These motor drives fully utilize the whole space, which makes them compact and effective. They arrange the stator to l

24、ocate the windings and excitations, hence resulting in the robust outer rotor. The concentrated armature windings with 36/24 fractional-slot structure can shorten the magnetic flux path and the span of end-windings, which lead to reduce both iron and copper materials. Moreover, this arrangement of w

25、indings can significantly reduce the cogging torque which usually occurs at conventional PM motor drives. Their different constructions also make them have distinct features. For the DSPM motor drive, it has simpler structure than the PMHB one. Also its control strategy is simpler. But this simple s

26、tructure limits its flexibility due to its uncontrollable airgap flux. For the PMHB motor drive, since it fully takes advantage of double excitations (both PMs and DC field windings), it can offer flexible airgap flux control, including flux strengthening or weakening. In addition, the air-bridge is

27、 present to shunt with each PM, hence amplifying the flux weakening ability. The corresponding field excitation inevitably causes additional power loss. Nevertheless, this reduction of efficiency can be partially compensated by the efficiency improvement due to airgap flux control. By properly tunin

28、g the airgap flux density, the efficiency can be online optimized at different speeds and loads. Fig. 4. Control strategies. (a) DSPM. (b) PMHB.Fig. 4 shows the control strategies of these two stator-PM motor drives, indicating that the PMHB motor drive has an additional flux controller to regulate

29、the airgap flux. The pole selection of the DSPM motor drive is governed by the following equations: N s = 2mk and N r = N s - 2k （1）where m is the number of phases, k the integer, N s the number of stator poles, and N rthe number of rotor poles. The pole selection of the PMHB motor drive is given by

30、: 4mp and 2Ns/m (2) where p is the number of pole pairs of the DC field windings.Therefore, when the suitable parameters are selected, namely m= 3, p= 3, and k= 6 , the poles of these stator-PM motor drives lead to be 36， and 24 . It can be found that for three-phase armature windings of the PMHB mo

31、tor drive, all the other parameters can be obtained according to the value of p. Hence, the aforementioned equation (2) can be used to simply determine the other possible slot-tooth combination for the PMHB motor drive.IV. ANALYSIS APPROACH The CFT-TS-FEM can be used to analyze the steady-state and

32、ransient performances of both machine drives. For each machine drive, the mathematic model consists of three sets of equations: the electromagnetic field equation of the machine, the circuit equation of the armature windings, and the motion equation of the motor drive. The electromagnetic field equation of both machine drives is given by 7:where is the field solution region, v the reluctivity, the electrical conductivity, J the current density, A the magnetic vector potential component along the z axis, and and the PM remanent flux density com