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FLUX ESTIMATION FOR A PERMANENT MAGNET GENERATOR OF A WIND TURBINE GENERATOR

IP.com Disclosure Number: IPCOM000245531D
Publication Date: 2016-Mar-15
Document File: 5 page(s) / 83K

Publishing Venue

The IP.com Prior Art Database

Abstract

According the concept as disclosed, the estimation of the rotor magnet flux of a permanent magnet (PM) generator of a wind turbine generator (WTG) may be improved by the following two aspects. A first aspect is the use of a voltage sensor during idling. A second aspect is the use of two estimation methods (e.g. using two parallel flux estimators) during operation, with a weighing function to combine to the two parallel estimators.

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FLUX ESTIMATION FOR A PERMANENT MAGNET GENERATOR OF A WIND TURBINE GENERATOR

     This disclosure relates to rotor magnet flux estimation and rotor magnet flux monitoring with regard to a permanent magnet (PM) generator of a wind

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turbine generator (WTG).

     In general, a WTG includes a tower and a nacelle located at the top of the tower. A WTG rotor may be connected with the nacelle through a low speed shaft extending out of the nacelle. The WTG rotor may include three rotor blades mounted on a common hub, but may include any suitable number of blades. The

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blade typically has an aerodynamic shape with a leading edge for facing into the wind, a trailing edge at the opposite end of a chord for the blade, a tip, and a root for attaching to the hub in any suitable manner. The blades may be connected to the hub using pitch bearings such that each blade may be rotated around its longitudinal axis to adjust the blade's pitch. The WTG includes an electrical

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generator (e.g. a PM generator) configured to convert the mechanical energy of the WTG rotor into one or more phases of electrical power as respective power outputs that are ultimately delivered to an electrical grid and to any loads connected therewith. The WTG may include a power converter system configured to couple with the electrical generator and with the electrical grid, and further 20

configured to convert alternating current (AC) power received from the electrical generator into AC power that is suitable for supplying to the electrical grid. The electrical generator may be of any suitable type, such as induction generators (IG), permanent magnet generators (PMG) with frequency-converters, doubly-fed induction generators, etc. The power converter system may include a power

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converter in form of a so called full-scale converter, including a generator-side converter (rectifier) connected to the electrical generator, a grid-side converter (inverter) connected to the grid and a DC-link connecting the generator-side converter and the grid-side converter to one another. The WTG may include WTG controllers to control the operation of the WTG, e.g. controlling the power 30

converter system and the electrical generator. The WTG may be part of a wind power plant (WPP) comprising a plurality of WTGs. The WPP may include a power plant controller (PPC) arranged to communicate with and send control signals to the individual WTGs.


Page 02 of 5

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     According to an aspect of the new concept as disclosed herein, the estimation of the rotor magnet flux of a PM generator may be improved by combing and (online) weighting a plurality (e.g. two, or more) flux estimation methods in order to obtain more precise flux estimation. The improved estimation can be used for various purposes, e.g. heath monitoring, demagnetization

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supervision and demagnetization protection (i.e. to protect the electrical generator of the WTG from demagnetization).

     If the magnets of the PM generator are subjected to too high...