Department of Electrical Engineering Southern Taiwan University of Science and Technology Robot and Servo Drive Lab. 2016/2/21 A Novel Rotor Configuration and Experimental Verification of Interior PM Synchronous Motor for High-Speed Applications IEEE TRANSACTIONS ON MAGNETICS, VOL. 48, NO. 2, FEBRUARY 2012 By Sung-Il Kim, Young-Kyoun Kim, Geun-Ho Lee,and Jung-Pyo Hong Professor ： Ming-Shyan Wang Student ： Hao-Chao Lin

Department of Electrical Engineering Southern Taiwan University of Science and Technology Outline Introduction CONFIGURATION AND DESIGN SPECIFICATIONS OF HIGH-SPEED SURFACE-MOUNTED PMSM ROTOR DESIGN OF HIGH-SPEED IPMSM Initial Rotor Shape Experimental Design Rotor-Shape Optimization TEST RESULTS AND DISCUSSION Conclusion References 2016/2/21 Robot and Servo Drive Lab. 2

Department of Electrical Engineering Southern Taiwan University of Science and Technology Introduction Recently, in many industrial applications, such as machine tools, vacuum pumps, and centrifugal compressors, the case applied to high-speed machines for miniaturization and weight reduction is growing more and more. The application of gearless directly coupled high-speed machines can prevent problems, such as oil leakage, maintenance costs, and gear losses, and increase the system reliability by simplifying the structure. Moreover, noise can also be considerably reduced by eliminating an additional transmission system. 2016/2/21 Robot and Servo Drive Lab. 3

Department of Electrical Engineering Southern Taiwan University of Science and Technology Introduction A permanent-magnet synchronous motor (PMSM) of varied motors, such as an induction motor and a reluctance motor, is becoming more and more favored than the high-speed machine. Due to the nonelectric excitation, rotor losses are very small, leading to minor thermal rotor expansion and to improved efficiency. 2016/2/21 Robot and Servo Drive Lab. 4

Department of Electrical Engineering Southern Taiwan University of Science and Technology CONFIGURATION AND DESIGN SPECIFICATIONS OF HIGH-SPEED SURFACE-MOUNTED PMSM The permanent magnet magnetized in the parallel direction is retained within a sleeve, which has been pressed on the rotor to withstand the centrifugal stress under high-speed operation. Especially, the permanent magnet and sleeve are divided as two parts in order to reduce eddy current loss. 2016/2/21 Robot and Servo Drive Lab. 5

Department of Electrical Engineering Southern Taiwan University of Science and Technology ROTOR DESIGN OF HIGH-SPEED IPMSM In this section, on the basis of specifications given in Table I, the optimal rotor configuration of an IPMSM is designed in order to obtain better performance than the surface-mounted 2016/2/21 Robot and Servo Drive Lab. 6 Manufactured stator with three-phase coils. (a) Top view. (b) Side view.

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 7

Department of Electrical Engineering Southern Taiwan University of Science and Technology Initial Rotor Shape of poles is restricted for stable control. When the poles are chosen, the fundamental frequency of the motor at maximum speed should typically be less than one-tenth of the switching frequency of an inverter. As a result, the number of IPMSM poles is limited to two in order to compare the SPMSM for driving the air blower. 2016/2/21 Robot and Servo Drive Lab. 8

Department of Electrical Engineering Southern Taiwan University of Science and Technology Experimental Design The rotor design of an IPMSM is a challenging task because of the conflict between improved performance and rotor complexity. For example, the thin rib of IPM machines results in better electromagnetic performance due to less leakage flux, but it may not be strong enough to withstand the centrifugal forces with the rotor speed increase. 2016/2/21 Robot and Servo Drive Lab. 9

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 10 Various rotor configurations of the two-pole IPMSM.

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 11 Partial rotor configurations according to design factor variation. (a) According to the number of magnet layers. (b) According to the number of bridges in the second layer. c) According to pole angle.

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 12

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 13 FEA results of FFD.

Department of Electrical Engineering Southern Taiwan University of Science and Technology Rotor-Shape Optimization The aim of the rotor optimization is to secure electrical performance and mechanical strength. In addition, the amount of PM should be minimized. Accordingly, as shown in Fig. 6, the design parameters based on the results of the experimental design are chosen for the optimization. 2016/2/21 Robot and Servo Drive Lab. 14

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 15

Department of Electrical Engineering Southern Taiwan University of Science and Technology 2016/2/21 Robot and Servo Drive Lab. 16 Configurations of fabricated IPMSM. (a) Rotor. (b) Rotor assembly. (c) Air blower.

Department of Electrical Engineering Southern Taiwan University of Science and Technology TEST RESULTS AND DISCUSSION The fabricated IPMSM are exhibited in Fig. 8. In order to verify the performance of the IPMSM, tests are carried out as shown in Fig. 9. The results obtained in the test are shown in Fig. 10. Input current of the IPMSM is somewhat increased because of low back-emf than the surface-mounted PMSM, but the efficiency measured below r/min is higher than the surface-mounted PMSM. 2016/2/21 Robot and Servo Drive Lab. 17

Department of Electrical Engineering Southern Taiwan University of Science and Technology Conclusion Even though current vector control is required to obtain maximum torque, the overall efficiency measured in the IPMSM is better than that of the SPMSM. In addition, the amount of permanent magnet actually used in the IPMSM is reduced by approximately 53% than the SPMSM. 2016/2/21 Robot and Servo Drive Lab. 18

Department of Electrical Engineering Southern Taiwan University of Science and Technology References [1] A. Binder, T. Schneider, and M. Klohr, “Fixation of buried and surface- mounted magnets in high-speed permanent magnet synchronous machines,” IEEE Trans. Ind. Appl., vol. 42, no. 4, pp. 1031–1037, Jul./ Aug [2] A. M. EL-Refaie, R. Manzke, and T. M. Jahns, “Application of bi-state magnetic material to automotive offset-couple IPM starter/alternator machine,” IEEE Trans. Ind. Appl.., vol. 40, no. 3, pp. 717–725, May/ Jun [3] E. C. Lovelace, T. M. Jahns, T. A. Keim, and J. H. Lang, “Mechanical design considerations for conventionally laminated, high-speed, interior PM synchronous machine rotors,” IEEE Trans. Ind. Appl., vol. 40, no. 3, pp. 806–812, May/Jun [4] J. M. Park, S. I. Kim, J. P. Hong, and J. H. Lee, “Rotor design on torque ripple reduction for a synchronous reluctance motor with concentrated winding using response surface methodology,” IEEE Trans. Magn., vol. 42, no. 10, pp. 3479–3481, Oct [5] B. H. Lee, S. O. Kwon, T. Sun, J. P. Hong, G. H. Lee, and J. Hur, “Modeling of core loss resistance for d-q equivalent circuit analysis of IPMSM considering harmonic linkage flux,” IEEE Trans. Magn., vol. 47, no. 5, pp. 1066–1069, May /2/21 19

Department of Electrical Engineering Southern Taiwan University of Science and Technology Thanks for listening 2016/2/21 Robot and Servo Drive Lab. 20