Position-sensorless smooth torque control of a squirrel cage synchronous reluctance motor

Position sensorless and smooth torque control for a commercially available squirrel cage synchronous reluctance machine is presented. Especially for traction applications (such as EVs) steady state and transient operations are of interest and a minimized torque ripple operation in any arbitrary mode is desired. The control method should be suited for fast acceleration and step changes in load. In the second part of this paper encoderless position estimation for a 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 a robust position estimation with a 4kW SyncRM are given.