Design of Large-Power Surface-Mounted Permanent-Magnet Motors Using Postassembly Magnetization

This paper reports the design process for the manufacture of higher-power rare-earth permanent-magnet (PM) motors using postassembly magnetization. Difficulties can be encountered in production using normal manufacturing processes due to the high intensity of rare-earth magnets that are premagnetized. Postassembly magnetization utilizes the stator windings of a PM motor to magnetize the magnets after assembly. With this method, some parameters, such as slot-fill factor, number of turns, wire diameter, etc., must be considered for the magnetization and motor operation. In this paper, a design process that incorporates the design considerations for postassembly magnetization (for complete magnetization) together with the design requirements is described for successful motor operation. A 6-kW surface-mounted PM (SPM) motor is designed using the proposed process as a demonstration, which is verified using finite-element analysis. Another 400-W SPM motor is also designed for experimental purpose. The experimental results validate the effectiveness of the proposed method.