Patent ID: 6456048
Filing Date: 2002-09-24
Classification: H02J,H02P,Y02T

Abstract:
An alternator for a vehicle, comprising:an AC generation section driven by a vehicle engine, and having a field coil and an armature coil; a rectifying means for rectifying AC voltage generated by said armature coil to DC voltage and charging an electricity accumulating means; a rotation speed detecting means for detecting an electricity amount related to rotation speed of said AC generation section; and a voltage control unit including a comparing section for comparing an electricity amount related to the DC voltage with a predetermined adjust voltage and a switch connected in series to said field coil, said voltage control unit converging the DC voltage to the adjust voltage by intermittently controlling said switch based on a compared result of said comparing section, wherein said voltage control unit includes a shift means for shifting a rotation speed of a driving torque inflection point of the alternator based on the electricity amount related to rotation speed so as to reduce the rotation speed of the driving torque inflection point in accordance with a reduction of the rotation speed, and in the driving torque inflection point, driving torque of the alternator suddenly changes as a result of an increase of duty ratio of said switch due to a shortage of generation capacity caused by a reduction of the rotation speed.