Estimation of the Fundamental Current in Low-Switching-Frequency High Dynamic Medium-Voltage Drives

Abstract

The switching frequency of medium-voltage ac drives is limited to low values to restrain the dynamic losses of the power devices. This favors the use of synchronous optimal pulsewidth-modulation schemes that minimize the harmonic current. It is a drawback, though, that optimal algorithms do not have a means to extract the fundamental component of the load current. High-performance torque control is therefore difficult to obtain. This paper proposes a method to identify the instantaneous fundamental component of the stator currents. A novel observer is developed for this purpose. The approach enables fast torque control at very low switching frequency. Experimental results from a 30-kW induction motor drive are presented.

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Cite this paper

@article{Holtz2007EstimationOT, title={Estimation of the Fundamental Current in Low-Switching-Frequency High Dynamic Medium-Voltage Drives}, author={Joachim Holtz and N. Oikonomou}, journal={2007 IEEE Industry Applications Annual Meeting}, year={2007}, pages={993-1000} }