Comparison of two sampling techniques of SVM applied in sensorless Field Oriented Controlled IM drive

Field Oriented Control (FOC) technique is one of the mostly applied algorithm to control the speed and the flux of a three-phase electric drive. The paper focuses on high speed or high-pole count motor FOC drives when both the sampling over reference frequency ratio F and the carrier over reference frequency m f is low. The paper presents that the stability range of a speed sensor-less FOC motor drive can be extended by recalculating the reference signal of the Space Vector Modulation (SVM) algorithm at the negative peak of the carrier signal as well by approximating the rotor flux angle change over one half carrier period. The result was verified by computer simulations and laboratory measurements.