Effects of high frequency excitation on the behavior of a switched reluctance machine

A host of applications in the military, automotive and domestic fields require machines capable of operating at very high speeds. Such applications warrant excitation frequencies at the stator in the order of 10's of kilohertz. However use of such high frequencies generates an additional source of magnetomotive force in the stator and rotor of the machine. These sources are originated by eddy currents and are distributed throughout the machine according to skin effects. Eddy currents are harder to model numerically and consequently the effects of this phenomenon are often neglected in the design and control. However they are seen to have a direct impact on the co-energy of the system which in turn affects torque generation of the machine. This paper investigates the effect of high frequency excitation on the performance of a switched reluctance machine (SRM). The machine model has been simulated using a three dimensional transient finite element analysis and resultant change in torque and other output parameters has been investigated. Also observed were changes in key operating parameters like inductance and resistance. Preliminary experimental and theoretical results are included to validate our claims