Calculation Methods and Effects of End-Winding Inductance and Permanent-Magnet End Flux on Performance Prediction of Nonoverlap Winding Permanent-Magnet Machines

• Published in: IEEE transactions on industry applications Vol. 50; no. 4; pp. 2458 - 2466
• Main Authors: Potgieter, Johannes H. J., Kamper, Maarten J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-07-2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: analytical models; Coils; Couplings; Design engineering; design optimization; end windings; Finite element method; finite element methods; Flux; flux fringing; Indication; Inductance; Iron; Lamination; Mathematical analysis; permanent magnet machines; Permanent magnets; saturation magnetization; Three dimensional; Winding; Windings; Analytical models; permanent-magnet (PM) machines; design optimization; flux fringing; inductance; end windings; saturation magnetization; finite-element (FE) methods
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2013.2295468

Due to the short end windings of nonoverlap winding permanent-magnet (PM) machines, the end-winding inductance component is generally ignored in the design. In most cases, the end-flux fringing effects in PMs are also not taken into account. It is shown in this paper that these end effects have a significant influence on the performance parameters of the machine. In this paper, several nonoverlap winding PM machines are considered with respect to the effects of end-winding inductance and PM end-flux fringing. A number of calculation methods for the per-phase end-winding inductance of the machines are compared. A new simple analytical calculation method is proposed, which is shown to give a relatively good prediction of the end-winding inductance compared with 3-D finite-element (FE) results. It is proposed in this paper that the PM strength should be reduced by a certain fringing factor to take the end-flux fringing effects into account in the 2-D FE analysis. Practical measurements are also presented to validate the FE calculations and to give an indication on the effects that are caused by the end-winding inductance and the PM end-flux fringing.