A Comparative Study of Two Permanent Magnet Motors Structures with Interior and Exterior Rotor

Abstract

Currently, the permanent magnet motors PMM represent an attractive solution in the electric traction field, thanks to their higher performances than other electric motors. In this context, this work represents an analytical study and validation by the finite element method of two configurations, the radial flux permanent magnet synchronous motors with exterior rotor PMSMER and with interior rotor PMSMIR. This paper is divided into two sections: In the first section, we represent the analytical study based on electromagnetic law of the two structures PMSMER and PMSMIR. In the second section, we represent a comparative study of the two structure performances. Keywords permanent magnet motors design, radial flux, finite element method, modelling, performance 1. INTRODUCTION Considering the large variety of electric motors, such as asynchronous motors, synchronous motors with variable reluctances, permanent magnet motors with radial or axial flux, the committed firms try to find the best choice of the motor conceived for electric vehicle field. There are different criteria of selection in order to solve this problem such as the power-to-weight ratio, the efficiency and the price. The traction electric motor is specified by several qualities, such as the flexibility , reliability, cleanliness, facility of maintenance, silence etc. Moreover, it must satisfy several requirements , for example the possession of a high torque and an important efficiency [Zire et al., 2003; Gasc, 2004; Chan, 2004]. In this context, The PMM is characterized by a high efficiency, very important torque, and power-to-weight, so it becomes very interesting for electric traction. The rotor of the PMM supports several configurations interesting for the magnets mounted on surface. In the intension, to ensure the most suitable and judicious choice, we start by a comparative study between the two structures, then, we implement a methodology of design based on an analytical modelling and on the electromagnetism laws.