Sensorless Synchronous Reluctance Motor Drives: Auxiliary Flux-Based Position Observer

The concept of auxiliary flux vector is defined for the nonlinear magnetic model of a synchronous reluctance (SyR) machine. An auxiliary flux-based position observer is developed to circumvent the stability problems of other schemes, notably active flux position observer, without compromising on the simplicity. Stability analysis and sensitivity to parameter errors are presented. The proposed observer is augmented with high-frequency signal injection-based position estimation for sustained operation at the low-speed region. The proposed technique is experimentally validated on a 1.1-kW SyR machine test bench.