Indirect rotor position sensing for switched reluctance motor using search coil

Tests were conducted on a prototype switched reluctance motor (SRM) to check the feasibility of using search coils to generate rotor position instead of an encoder. Two significant advantages of using search coils to identify rotor position are: (1) the rotor position is always available; and (2) the effect of sensing current on output torque ripple is negligible due to the small current in the search coil. Initial experimental results indicate that the search coil technique does provide rotor position information with a resolution of approximately 0.6 mechanical degrees for an 8/6 design SRM.