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- Felicetti, Roberto, 1972-, et al.
(författare)
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An experimentally determined field winding model with frequency-dependent parameters
- 2021
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Ingår i: IET Electric Power Applications. - : Institution of Engineering and Technology. - 1751-8660 .- 1751-8679. ; 15:6, s. 696-716
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Tidskriftsartikel (refereegranskat)abstract
- Herein, a set of experimental procedures is presented for determining the main electrical distributed parameters of the field winding in salient pole synchronous machines. It applies to the electrical characterisation of iron-core power inductors and transformer windings as well, in a range of frequency useful for power electronics applications. A first estimation of the parameters is obtained by forcing the winding into resonance with capacitors of known capacitance. The obtained estimates are then refined through an iterative process, which makes use of the winding natural frequencies. The presented procedures are applied step-by-step to the field winding of a 60-kVA salient pole synchronous generator with solid poles. The distributed parameters model, featured using the outlined procedures, accurately reproduces the winding voltage distribution in a large range of frequency. Finally, it is explored how the interaction between armature and rotor influences the field winding parameters, pointing to the differences of measuring them with the rotor inside or outside the machine bore.
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| 2. |
- Felicetti, Roberto, 1972-
(författare)
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Voltage Transients in the Field Winding of Salient Pole Wound Synchronous Machines : Implications from fast switching power electronics
- 2021
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Wound Field Synchronous Generators provide more than 95% of the electricity need worldwide. Their primacy in electricity production is due to ease of voltage regulation, performed by simply adjusting the direct current intensity in their rotor winding. Nevertheless, the rapid progress of power electronics devices enables new possibilities for alternating current add-ins in a more than a century long DC dominated technology. Damping the rotor oscillations with less energy loss than before, reducing the wear of the bearings by actively compensating for the mechanic unbalance of the rotating parts, speeding up the generator with no need for additional means, these are just few of the new applications which imply partial or total alternated current supplying of the rotor winding.This thesis explores what happens in a winding traditionally designed for the direct current supply when an alternated current is injected into it by an inverter. The research focuses on wound field salient pole synchronous machines and investigates the changes in the field winding parameters under AC conditions. Particular attention is dedicated to the potentially harmful voltage surges and voltage gradients triggered by voltage-edges with large slew rate. For this study a wide frequency band simplified electromagnetic model of the field winding has been carried out, experimentally determined and validated. Within the specific application of the fast field current control, the research provides some references for the design of the rotor magnetic circuit and of the field winding. Finally the coordination between the power electronics and the field winding properties is addressed, when the current control is done by means of a long cable or busbars, in order to prevent or reduce the ringing.
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