PMSM position sensorless control with extended flux observer

So far a lot of sensorless control methods have been proposed for permanent-magnet synchronous motors (PMSM). However, application which require the response at transition is limited in current methods, and the expansion of coverage of sensorless control is requested. In this paper, an extended flux is defined and minimal order observer estimating it is proposed. Then, the poles of the minimal order observer are assigned, considering robustness to velocity estimation error and suppression of higher harmonic components. Assigning poles like this, this observer becomes robuster to velocity estimation error at transition than conventional method. By this characteristic, the improvement of the response can be expected. The performance of proposed method is shown by experiments.