Investigation of estimator algorithms for high speed drive systems

In high speed drives both the sampling over reference frequency ratio F and the carrier over reference frequency m
_f
is a low value. The low m
_f
ratio results voltage and current harmonic spectra far more unfavorable than at standard ratios. The low F ratio can result uncertainty and inaccuracy in the calculation of the magnitude and angle of stator or rotor flux vector or in the estimation of the actual value of the speed. The current paper derives the discrete equations of different flux and speed estimator algorithms by using Tustin approximation. The performance of the algorithms, both in open and closed loop, is demonstrated via numerical simulation using a high speed motor drive with a low sampling to fundamental frequency ratio.