Computer-aided design of a permanent magnet motor

Abstract

Although neodymium-iron-boron (Nd-Fe-B) magnets have high-energy product with suitable magnetic and physical properties for applications in electrical machines, the design of permanent magnet (PM) motors is a complicated problem due to their complex geometries and PM material characteristics. This paper initially compares various PM motor geometries and describes their PM material outlay, armature reaction and mechanical integrity. By the employment of appropriately located air slots to reduce the armature reaction in conjunction with flux enhancement arrangement without detracting from its mechanical integrity, a new rotor geometry for a high-field high-speed PM synchronous motor is proposed. Computer-aided electromagnetic calculation and graphical evaluation are employed for the design and optimization of the proposed PM motor. An idea of 'computer job delegation' is proposed and implemented within the computer system to provide full utilization of each computer's capabilities as well as parallel operation of the design and optimization process. The proposed rotor geometry and design philosophy have been implemented to design a 3.2 kW PM synchronous motor.