Analysis of Rotor Core Eddy-Current Losses in Interior Permanent Magnet Synchronous Machines

This paper presents the results of an investigation focused on the rotor core eddy-current losses of interior permanent magnet (IPM) synchronous machines. First, analytical insight into the rotor core eddy-current losses of IPM machines is developed. Next, major design parameters that have the most significant impact on the rotor core eddy-current losses of IPM machines are identified. Finite element analysis results are then presented to compare the predicted eddy-current losses in the machine core of IPM machines with one- and two-layer rotors coupled with concentrated- and distributed-winding stators. It is shown that the lowest total eddy-current losses in the machine core are achieved using a combination of distributed stator windings and two magnet layers per rotor pole, while minimizing only the rotor core eddy-current losses favors replacement of the rotor with a single-layer configuration.

[1]  T.M. Jahns,et al.  Torque Ripple Reduction in Interior Permanent Magnet Synchronous Machines Using the Principle of Mutual Harmonics Exclusion , 2007, 2007 IEEE Industry Applications Annual Meeting.

[2]  K. Yamazaki,et al.  Loss Analysis of Interior Permanent Magnet Motors Considering Carrier Harmonics and Magnet Eddy Currents Using 3-D FEM , 2007, 2007 IEEE International Electric Machines & Drives Conference.

[3]  K. Yamazaki,et al.  Iron loss analysis of interior permanent-magnet synchronous motors-variation of main loss factors due to driving condition , 2005, IEEE Transactions on Industry Applications.

[4]  Z. Zhu,et al.  Eddy current loss in a moving-coil tubular permanent magnet motor , 1999 .

[5]  Fang Deng.  Commutation-caused eddy-current losses in permanent-magnet brushless DC motors , 1997 .

[6]  A. Brockmeyer.  Experimental evaluation of the influence of DC-premagnetization on the properties of power electronic ferrites , 1996, Proceedings of Applied Power Electronics Conference. APEC '96.

[7]  D. Howe,et al.  Eddy current loss in a moving-coil linear tubular permatant magnet brushless motor , 1999, IEEE International Magnetics Conference.

[8]  Nigel Schofield,et al.  Improved analytical modelling of rotor eddy current loss in brushless machines equipped with surface-mounted permanent magnets , 2004 .

[9]  R. L. Stoll,et al.  Comparison between analytical and numerical methods of calculating tooth ripple losses in salient pole synchronous machines , 2001 .

[10]  T.M. Jahns,et al.  An Analytical Design Approach for Reducing Stator Iron Losses in Interior PM Synchronous Machines During Flux-Weakening Operation , 2007, 2007 IEEE Industry Applications Annual Meeting.

[11]  P. Biringer,et al.  A simple method of estimating the minor loop hysteresis loss in thin laminations , 1978 .

[12]  Z. Zhu,et al.  Eddy-current loss in the rotor magnets of permanent-magnet brushless machines having a fractional number of slots per pole , 2005, IEEE Transactions on Magnetics.

[13]  D. Stone,et al.  Rotor loss in permanent magnet brushless AC machines , 1999, IEEE International Electric Machines and Drives Conference. IEMDC'99. Proceedings (Cat. No.99EX272).