Adopting a SOGI filter for flux-linkage based rotor position sensing of switched reluctance machines

Position sensorless control of switched reluctance motors reduces the system cost and increases the drives overall reliability. The flux-linkage method is a commonly applied technique when sensorless control of switched reluctance motors is pursued. The sensing quality, though being sensitive to model errors and further effects, can be sufficient for a number of applications. However, sophisticated control algorithms like predictive direct instantaneous torque control and direct instantaneous force control require highly accurate rotor position estimation. Current profiling methods rely on accurate position sensing as well. The main objective of the present paper is the improvement of the conventional flux-linkage method by adopting a band pass filter and a self-characterization routine. As a result the estimation error can be crucially reduced and the operation area of the flux-linkage method can be expanded. The paper includes simulative and experimental validation of the algorithm.