Control device and control method for a vehicle AC generator

Abstract

The control device including: a power transistor (502) for controlling conduction/non-conduction of a field coil (3) in accordance with an output voltage of an AC generator (1) mounted on a vehicle; an RPM detection section (511) for detecting an RPM of the AC generator (1); a drive duty setting section (510) for determining whether or not the RPM detected by the RPM detection section (511) is equal to or higher than a predetermined threshold, and reducing a conduction ratio of the field coil (3) when determining that the RPM is equal to or higher than the predetermined threshold; and a driver (504) for driving the power transistor (502) based on the conduction ratio. In this manner, the conduction ratio of the field coil (3) is reduced to suppress the drive torque.

Dependencies are inferred from the claim text.