Research on Permanent Magnet Brushless DC Motor Based on Bonded Magnets

Abstract

The ring-shaped bonded magnet has the advantages of low cost, simple molding, easy assembly, and low eddy current loss, but it has weak magnetic performance. To improve the comprehensive performance of the motor, the motor structure needs to be optimized. In this paper, the ring-shaped bonded magnet is applied to the permanent magnet brushless DC(PMBLDC) motor. According to the characteristics of ring-shaped bonded magnet, a multi-parameter and multi-objective optimization method is proposed to shorten the design time and improve the optimization effect. Based on the equivalent magnetic circuit model, the key parameters affecting the motor performance are derived, then the requirements of permanent magnet demagnetization and motor stability are used as constraints to determine the range of parameter values. The sample data sets of the relationship between the structural parameters and the motor performance are established by the Taguchi method. The quadratic response surface regression model is used to fit the sample data set. Then the modified ant colony algorithm is used to search the optimal target. According to the optimized motor structure parameters, the motor prototype is processed. The results show that the optimized structure can effectively improve the output torque and reduce the cogging torque, torque ripple and operating noise without reducing the efficiency. The research results provide a basis for further development of the application of ring-shaped bonded magnet in micro-motors, and drive the development of motors with lightweight, miniaturization and low cost.