Position estimation at zero speed for PMSM using the principal component analysis

The article proposes a method for estimating the shaft position of a synchronous motor with permanent magnets for the zero and very low speed range. Presented method involves a comparison of obtained shape of current hodograph to the reference pattern using the principal component analysis. The method is based on an analyzing of the high frequency currents, which are excited by high frequency additional voltages. Although this method imply the recognition of a currents hodograph, in a case of using this method, it is no necessity to calculating the ellipse position. The method can achieve satisfactory accuracy in a case the high asymmetry of the inductance, as well as in the case of small values of the inductance asymmetry ratio, also in the case of a presence of a measurement noise.