Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Stellenbosch, Stellenbosch 7600, South Africa; Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, United Kingdom
Potgieter, J.H.J., Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Stellenbosch, Stellenbosch 7600, South Africa, Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, United Kingdom; Kamper, M.J., Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Stellenbosch, Stellenbosch 7600, South Africa
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. © 2013 IEEE.
