Magnetics Business & Technology - Spring 2013 - (Page 12)

FEATURE ARTICLE Simulating the Toyota Prius Electric Motor By Robert Kaczmarek, Vice President of Sales and Marketing • Cobham Technical Services – Vector Fields Software This article is intended to look at the implementation of electromagnetic Finite Element Analysis in a real world problem in order to gain insights and best practices around this type of analysis. In order to do so we have taken the published results of the Toyota Prius motor by Oak Ridge National Laboratory (ORNL) papers [1][5] and compiled a simulation based upon them. Through this process there were Toyota Prius Motor [1] various challenges and ultimately lessons learned that can be translated into various different areas of Computer Aided Engineering. While both 3D and 2D analysis were run we detailed the 2D analysis in this article. For this simulation we used Opera Machines Environment (www.operaFEA.com) by Cobham Technical Services – Vector Fields Software. Figure 1. Geometric outline of the PRIUS motor Motor Characteristics - The 2004 Toyota Prius Hybrid Vehicle uses a three phase, 48 slots, embedded permanent magnet motor with eight poles. The windings are distributed, single layered with nine turns per slot and connected in series. Geometric Dimensions - The external diameter of the stator is 269.24 mm and the stack length is 83.56 mm. The resulting air gap for the Prius PMSM is 0.75 mm. The V-shaped magnets are housed in specially designed rotor slots that aim to increase the quadrature-axis reactance in order to improve the motor’s performance. The air regions at the top of the magnet cutaway are designed to narrow the flux bridge in order to further increase Xq, as seen in Figure 1. Magnetic Characteristics - The material used for the stator and rotor cores definition is M19 laminated steel based on the magnetic data provided by the manufacturer. The permanent magnets are characterised in the ORNL paper [1] and the BH curve used in the modelling is obtained by interpolating the measured points. However, these do not explicitly match the materials used in the real motor, which most likely accounts for the slight difference between measured and simulated data. Figure 2. Machine type selection dialog Measured Data - The tests published by ORNL cover a wide range of mechanical, electromagnetic, thermal and energy efficiency characteristics. The purpose of this application note is to compare the electromagnetic characteristics of the ME2D model against the ones produced by the real motor. Therefore, only the electromagnetic tests of the traction motor are considered in the following comparisons. Analysis - The Finite Element Analysis was entirely done within Opera Machines Environment by Cobham Technical Services – Vector Fields Software in both 2D and 3D. Opera Machines Environment 2D - The 2D Machines Environment is an automated toolbox that aids in the design of electrical machines within Opera FEM software. After opening Opera’s Machines Environment the type of electrical machine needs to be selected from the list. In this case, the Permanent Magnet Embedded machine is selected (Figure 2). 12 Magnetics Business & Technology • Spring 2013 Figure 3. Rotor dimensions dialog www.MagneticsMagazine.com http://www.operaFEA.com http://www.MagneticsMagazine.com

Table of Contents for the Digital Edition of Magnetics Business & Technology - Spring 2013

Magnetics Business & Technology - Spring 2013
Editor's Choice
Dysprosium-Free Rare Earth Magnets for High Temperature Applications
Research & Development
Simulating the Toyota Prius Electric Motor
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Marketplace/Advertising Index
Spontaneous Thoughts: Dysprosium 2.0

Magnetics Business & Technology - Spring 2013