Design of Permanent Magnet Systems Using Finite Element Analysis

Rare earth permanent magnets have a wide range of magnetic properties to meet the requirements of an extensive variety of applications. Sintered Sm2Co17-type magnets have the best thermal stability with high magnetic performance at temperatures up to 550 °C. Sintered NdFeB magnets have the highest maximum energy product, (BH)max, but are limited to applications with relatively low operating temperatures. Bonded magnets offer some design flexibility at the expense of magnetic properties. In view of these complexities, it is very important to understand the critical factors when designing the magnetic circuit. Using design examples based on finite element analysis (FEA), we will discuss magnetic materials selection, magnetic circuit design principles and design trade-offs for various applications.