Investigation of direct flux measurements in switched reluctance motors

This paper investigates the use embedded magnetic field sensors in estimating the torque produced by a switched reluctance motor. Recent advances in nanomaterials have enabled the development of very compact magnetic field sensors based on the Giant Magneto Resistive (GMR) effect. This provides a direct measurement of internal magnetic flux levels of an electric machine during operation. With this capability, results are applied analytically to a switched reluctance motor to measure the flux distribution across the surface of a stator tooth. This data is then used in a discrete form of the Maxwell stress tensor to approximate the net torque at the motor shaft. Detailed results are given from a finite element study of a commercially produced switched reluctance motor.