Improvement of BLDC motor performance through magnetization pattern change in permanent magnets

Summary form only given. The effects of magnetization patterns on motor performance in a brushless DC motor are studied through FE analysis and experiments. Various magnetization patterns were obtained by changing the geometry of the magnetizing fixture. Nine different magnetizing fixtures were used to magnetize NdFeB ring magnets. Prototype motors were assembled and BEMF profiles and cogging torque were examined. The results show that BEMF profiles and cogging torque heavily depend on magnetization patterns. Improvement of motor performance includes 50% reduction in BEMF ripple and 80% reduction in cogging torque. A FE model was used to predict each magnetization pattern by simulating magnetizing process. The magnetization profiles were examined to identify the magnetization patterns. Each of the magnetization patterns has different magnetization profiles, which led to the difference in motor performance. It is shown that appropriate magnetizing fixture design leads to reduction in cogging torque and BEMF ripple.