Investigation of magnet arrangements in Double Layer Interior Synchronous Permanent Magnet Motor over wide-speed range for Electric Vehicle applications Athanasios G. Sarigiannidis 1,a , Minos E. Beniakar 1 , Panagiotis E. Kakosimos 1 and Antonios G. Kladas 1 1 School of Electrical and Computer Engineering, National Technical University of Athens, GR-15780, Athens, Greece a thsarig@central.ntua.gr Keywords: Interior Synchronous Permanent Magnet Motors, field weakening capability, Maximum Torque per Ampere control, magnetic saturation, finite elements, electric vehicle applications. Abstract. In this paper, the magnet arrangement for a manufactured Double Layer Interior Synchronous Permanent Magnet Motor (DLISPMM) for Electric Vehicle (EV) applications is investigated. In a first step, the manufactured motor is optimized for its nominal condition, by using a particular design of experiment (DOE) method. In a second step, a comparative analysis for the two types of DLISPMMs for a wide speed range operation is performed, by using a parametric Finite Element (FE) model, for calculation of the main machine characteristics, in conjunction with a convenient dynamic model, considering magnetic saturation, for implementation of field weakening control. The initial linear and the final, considering magnetic saturation, dynamic models are evaluated. Finally, the initial and final designs are compared in terms of the main operating characteristics for both nominal low speed and high speed field weakening operation. Introduction The Interior Permanent Synchronous Magnet Motors (IPSMMs) are considered to be an advantageous option for EV applications, due to their superior nominal characteristics, including high efficiency, torque density and a wide speed operating range, with the adequate magnet shielding, issues of crucial importance in EV applications [1,3]. In IPMM with single layer (SL) permanent magnet, the saliency in magnetic circuit, as illustrated in figure 1a creates a discrepancy in d and q axis inductances, resulting in a reluctance torque, additional to the magnet torque produced by the permanent magnets. In order to enhance the saliency of the magnetic circuit and extend the speed range, DLISPMM configurations are adopted [1]. Generally speaking, there are several topologies for DLISPMM [2]. In this paper, the 2I and VI topologies, as illustrated in Fig. 1b and 1c, respectively, will be analyzed, over wide speed range. The DLISPMM for EV applications manufactured by Brusa Electronik, is a 2I topology [1], with its main dimensional and operational characteristics, taken by a FE analysis, tabulated in table 1. Table 1. Initial DLISPMM configuration Main Dimensional Characteristics Nominal Operational Characteristics Phases, Poles, Slots 3, 6, 54 P=Power [kW], n=Speed [rpm] 16.5, 2000 R so =Diameter of stator [cm] 24 J=Current density [A/mm 2 ] 4.5 L=core length [cm] 12.3 T e , T ripple =Mean Torque [Nm], Torque ripple (%) 78.9, 35.9 l 1mag , l 2mag =1 st , 2 nd layer magnet length [mm] 39 , 21 EMF rms =Induced back electromagnetic force [V] 76.3 w 1mag , w 2mag =1 st , 2 nd layer magnet width [mm] 7.8, 4 Φ mag =Flux linkage induced by magnets [Wb] 0.1205 D s =Slot depth, T w =Tooth width [mm] 20.9, 5.4 P FE, P cu =Iron, Copper losses [W], η=efficiency (%) 153, 846, 94.81 Materials Science Forum Vol. 792 (2014) pp 379-384 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/MSF.792.379