Encoderless position estimation of a squirrel cage synchronous reluctance machine

Position sensorless control for a commercially available squirrel cage synchronous reluctance machine is presented. The contributions of this paper are twofold. First encoderless position estimation for a squirrel cage synchronous reluctance machine using high frequency carrier signal injection is shown. The estimation accuracy and dynamic properties in particular at low speed have been investigated. Experimental results of robust position estimation with a 4 kW SyncRM are given. Second, a rather general approach to increase the SNR for small and noisy signal is presented. Especially for machines without a distinct saliency image, the low signal-to-noise ratio is problematic. Extract the desired signal and distinguish from unwanted frequencies is a precarious issue.