[IEEE Ind. Appl.] Influence of Converter Topology and Carrier Frequency on Airgap Field Harmonics, Magnetic Forces, and Vibrations in Converter-Fed Hydropower Generator

AuthorsMostafa Valavi; Emile Devillers; Jean Le Besnerais ; Arve Nysveen ; Roy Nilsen
StatusPublished in: IEEE Transactions on Industrial Applications
KeywordsFractional–slot windings, hydrogenerator, pumped-storage hydro, radial forces, vibration


This paper investigates the effects of converter-fed operation on magnetic forces and vibration in a hydrogenerator. The variable–speed hydrogenerator (in a pumped–storage power plant) is a large synchronous machine with fractional–slot windings and supplies either resistive load or voltage source converter. Loading cases include two–level converter and three–level neutral–point–clamped converter and the carrier frequency is equal to 450Hz and 1050Hz. Using electromagnetic finite element (FE) analysis, airgap flux density harmonics are analyzed in different loading cases. In addition, electromagnetic torque and also variations in the rotor field current are also studied. Using Maxwell stress tensor, radial force density distribution in the airgap is investigated and the effect of converter-fed operation on different radial force harmonics are studied. Moreover, structural analysis and electromagnetic vibration synthesis are presented to investigate the effect of converter harmonics on the stator vibration.

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Vibroacoustic analysis of this paper has been run with MANATEE software, using its third party electromagnetic software import feature .