Rotor position estimation in a switched reluctance motor using embedded magnetic field sensors

This paper presents a new approach for estimating the switched reluctance (SR) motor rotor position using a giant magneto resistive (GMR) sensor embedded in the airgap. Recent development with GMR sensors and wavelet theory make this approach possible with advantages over conventional methods of direct shaft measurements using encoders or various sensorless techniques derived from terminal characteristics. This paper proposes a method that evaluates the product of the instantaneous components if the airgap field flux density values across the rotor arc, thereby extracting information on the rotor position using a wavelet decomposition. Results from a detailed finite element analysis of a commercially available SR motor are presented.