Estimation of Electromagnetic Force Using Strain Gauges Attached to Iron Cores

A novel electromagnetic force estimation using strain gauges attached to a laminated iron core method is proposed. Based on the strain gauge output, the electromagnetic force that occurs on the air-gap surface of the core is estimated with compensations for magnetostriction and nonuniform strain distribution. The proposed method is validated by comparing the electromagnetic force calculated in the finite element analysis and an experiment on a pair of C-shaped laminated iron cores. This article focuses on the force estimation in a pair of simple C-shaped cores, which are aimed at being a part of the stator and rotor of a switched reluctance machine. In future research, this basic approach will be extended to the estimation of the radial forces in switched reluctance motors to reduce the vibration and acoustic noise.