Influence of the Cost Function on the Optimal Design of Magnetic Hysteresis Couplings

The transmission of a constant torque from zero to synchronous speed with low torque ripple via simple electromechanical devices is an important requirement for a wide range of industrial applications. Hysteresis couplers or clutches can be useful to improve the aforementioned performance indexes, thanks to their unique features. This paper analyzes the influence of the cost functions in the design optimization of magnetic hysteresis couplings. After a brief re-call of a fast method of analysis, several configurations are compared by optimizing the coupler geometry in order to maximize the average torque and minimize the amount of rare-earth material. The obtained results are then deeply analyzed allowing to draw general design guidelines with special emphasis on the influence of the number of poles, cost functions, outer envelope as well as the airgap thickness on the main performance indexes.