Patent ID: 6093993
Filing Date: 2000-07-25
Classification: H02K

Abstract:
A switched reluctance motor having a torque output, the reluctance motor comprising a rotor defining rotor poles, a stator defining stator poles, at least one phase winding arranged in relation to the stator for excitation of the stator poles, a voltage source, switch means electrically connected between the voltage source and the at least one phase winding, control means operable to time actuation of the switch means to cause a current to flow in the at least one phase winding to excite the stator poles, the rotor and stator each comprising a stack of laminations, each of said laminations having a profile defining an array of salient pole pieces, said rotor lamination pole pieces and said stator lamination pole pieces extending one toward another, interpolar axes being defined between adjacent ones of said pole pieces on each of said laminations, faces of the pole pieces being movable past one another to define a variable air gap between them, and variation in the air gap being such that a first derivative of the variation of the air gap with respect to rotor angle is substantially continuous between adjacent ones of said interpolar axes of the rotor lamination, the pole pieces thus being constructed to smooth the torque output of the reluctance motor as the rotor moves relative to the stator, the structure of the pole pieces reducing torque ripple in the torque output of the reluctance motor.