Analytical approach to cogging torque calculation in PM brushless motors

The paper discusses the approach to analytical calculation of the cogging torque in PM brushless motors. Magnetic field energy in the air gap has been used to calculate the torque. Two equations have been derived: with the PM width taken into account, and simplified equation, i.e., without the effect of the finite width of the PM. The effect of eccentricity has been included too. Analytical results have been compared with laboratory test results.

[1]  S. X. Chen,et al.  Design trends of spindle motors for high performance hard disk drives , 1996 .

[2]  D. Howe,et al.  Analytical prediction of the cogging torque in radial-field permanent magnet brushless motors , 1992 .

[3]  B. J. Chalmers,et al.  Influence of machine symmetry on reduction of cogging torque in permanent-magnet brushless motors , 2000 .

[4]  Nicola Bianchi,et al.  Design techniques for reducing the cogging torque in surface-mounted PM motors , 2000, Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129).

[5]  D. C. Hanselman,et al.  Effect of skew, pole count and slot count on brushless motor radial force, cogging torque and back EMF , 1997 .

[6]  J. De La Ree,et al.  Torque production in permanent-magnet synchronous motors , 1989 .

[7]  B. Heller,et al.  Harmonic field effects in induction machines , 1977 .

[8]  B. Ackermann,et al.  New technique for reducing cogging torque in a class of brushless DC motors , 1992 .

[9]  T. Miller,et al.  Prediction of cogging torque using the flux-MMF diagram technique , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[10]  Z. Zhu,et al.  Influence of design parameters on cogging torque in permanent magnet machines , 1997 .

[11]  J Gieras.  ELECTRODYNAMIC LEVITATION FORCES--THEORY AND SMALL-SCALE TEST RESULTS , 1981 .