| 摘要 |
The invention relates to a method to detect a decrease of the demagnetization of permanent magnets (32) of the generator (12) of a wind turbine (1), wherein a frequency converter (14) is able adapt the variable frequency (f1) of the generator output voltage (Vout) to the frequency (f2) of a power grid (19), wherein
the AC/DC converter (13) or the DC/AC converter (16) of the frequency converter (14) is been disabled,
the electrical connections (Vout) between the generator (12) and the frequency converter (14) are switched on via circuit breakers (17),
the generator speed ( É ) is determined;
the generator output voltage (Vout) is determined by a voltage sensor (21) which is part of the frequency converter (14),
the magnetic flux density (Æ) of the generator (12) is calculated depending on the generator speed ( É ) and the generator output voltage (Vout),
a demagnetization event is determined by comparing the resulting flux density value (Æres) with a predetermined flux density value (Æref). |
