The presentation in the synchronous dq coordinate system presumes the orientation of the rotor flux as well as the mag- netic anisotropy to be known. Usually, however, this is not the case when applying encoderless control. For that reason all state variables are transformed to a coordinate system by an estimated transformation angle a ˆ δ , which ideally rotates synchronously with the dq coordinate system coupled to the saturation anisotropy of the synchronous machine.