Patent ID: 8303256

Claim:
A blade pitch driving apparatus for a wind-driven generator, the apparatus receiving an external electrical power and impelling a corresponding blade to a corresponding pitch angle, the apparatus comprising: an uninterruptible power supply (UPS), providing an uninterruptible electrical power; a permanent magnet synchronous motor drive (PMSM drive), electrically connected to the external electrical power to generate a driving electrical power; an alternating current pitch motor (ACPM), selectively and electrically connected to either the UPS or the PMSM drive, for generating a rotary power; a reduction gear box, coupled with a rotation shaft of the ACPM, for impelling the blade to change the pitch angle of the blade; and a hub controller, electrically connected to the PMSM drive and the ACPM, wherein the hub controller switches the PMSM drive to be electrically connected to the ACPM during a normal condition, and when the PMSM drive fails or the external electrical power is interrupted, the hub controller switches the UPS to be electrically connected to the ACPM.