Design and analysis of Halbach array permanent magnet motor for high acceleration applications

This work presents an optimal design method of the Halbach array based permanent magnet motors for applications which demand high acceleration, high torque, and high power density. Comparison between the conventional surface-mounted solid rotor PM machines (SMPM) and the Halbach array based hollow rotor PM machines is carried out. It is found that the Halbach array based PM machines are better candidates for applications which require high torque density and fast dynamic response. A parametric solution based method is proposed for obtaining the optimum dimensions of the Halbach array based PM machines. This method incorporates the acceleration torque requirements of the machine in the design equations and finds the optimum dimensions of the rotor which will produce the maximum output torque. To design the stator of the high speed machine, various distributed stator windings with lower slot numbers are analyzed. A nine-slot stator winding distribution, which produces higher output torque with lower torque ripple, is proposed. FEA results are presented for the validation of the proposed design.