Method For Monitoring Demagnetization

• US 20140049285A1
• Filed: 10/29/2013
• Published: 02/20/2014
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Schweiz AG (ABB Limited)
• Inventors: Rodriguez, Pedro
• Granted Patent: US 9,823,308 B2
• Time in Patent Office: Days
• US Class Current: 324/765.01
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: H02P 29/02 Providing protection against overload without automatic interruption of supply protection against faults of stepper motors H02P8/36

Abstract

A method for discovering demagnetisation faults of a permanent magnet synchronous generator, such as a wind power generator. The method is performed during operation of the synchronous generator and includes measuring the vibration of the stator, performing a frequency analysis of the vibration, and deducing whether the generator suffers from demagnetization of a permanent magnet, from the vibration analysis. Moreover, geometric eccentricity faults and electric short circuit faults may also be detected from the vibration.

Claims

1. A method for monitoring demagnetization of permanent magnets in a synchronous machine, such as a wind power generator, having a stator with windings and a rotor with permanent magnets being arranged to rotate in relation to the stator, the method being performed during operation of the synchronous machine, and the method including the steps of:

measuring the vibration of the stator,

performing a frequency analysis of the vibration,

determining, on the basis of whether the magnitude of the vibration at the supply frequency of the stator exceeds a threshold value or not, whether the machine suffers from demagnetization of a permanent magnet or not.

2. The method according to claim 1, wherein the method further comprises the step of:

determining, on the basis of whether the magnitude of the vibration at the rotation frequency exceeds a threshold value or not, whether the machine suffers from demagnetization of a permanent magnet or not.

3. The method according to claim 1, wherein the vibration measurement includes detecting vibrations by means of a vibration sensor that is fixed to a frame of the stator or fixed to the stator.

4. The method according to claim 1, wherein the machine is a permanent magnet synchronous generator.