An Improved Design of Slot and Tooth Dimensions of Fault-Tolerant Permanent Magnet Machine in Electromechanical Actuators

This paper has analyzed the magnetic circuit of three-phase 24-slot 20-pole fault tolerant permanent magnet machine in order to make the machine in electromechanical actuators have fault tolerant capability and large torque. It has been found that large inductance of fault-tolerant permanent magnet machine has been realized by increasing the stator tooth tip leakage inductance. Analytic expression of the tooth tip leakage inductance has been derived by using the flux tube approach. The tooth tip leakage inductance is affected by the slot and tooth dimensions. Sensitivity function of the slot and tooth dimensions has been introduced, some parameters which have remarkable influences on the machine performance have been found, and these parameters have been analyzed by using the finite element method. Finally, the selection zone of the slot and tooth dimensions has been acquired from the finite element results. Therefore, the analytic results can provide a reference for the fault tolerant permanent magnet machine optimization design.