Performance Analysis of a PM Claw Pole SMC Motor with Brushless DC Control Scheme

Abstract

Thanks to its unique properties, such as isotropic magnetic and thermal properties and low eddy current loss, the soft magnetic composite (SMC) material is suitable for application in electrical machines, especially those with complex structures and three-dimensional (3D) magnetic fluxes. This paper presents the performance analysis of a three-stack permanent magnet (PM) claw pole motor with an SMC stator core. 3D finite element magnetic analysis and improved formulations are applied to accurately compute the motor parameters, such as the back electromotive force, incremental inductance, cogging torque, and core loss. An equivalent electrical circuit is derived to predict the motor's steady-state performance under a brushless DC control scheme. Because of the large winding inductance of this type of motors, the control of the output torque and speed can be difficult. To verify the motor controllability, a Matlab/Simulink-based simulation model is compiled to simulate the motor dynamic and steady-state performances. Experiments are conducted on the motor prototype, validating the theoretical computations and analyses.