Patent ID: 6957636

Claim:
An apparatus for preventing an overshoot in a rotation speed of an internal-combustion engine, comprising: a starter/battery charger that includes 3-phase armature coils, is coupled to a crank shaft of the internal-combustion engine, operates as a starting motor for starting the internal-combustion engine, and also operates as a charging generator for charging a battery after the internal-combustion engine has been started; and a controller for performing a driving control for causing the starter/battery charger to generate positive torque and a braking control for causing the starter/battery charger to generate negative torque and thereby controlling the rotation speed of the internal-combustion engine, wherein the controller causes the starter/battery charger to generate negative torque in the braking control by effecting a 3-phase short-circuiting between phases of the 3-phase armature coils of the starter/battery charger, to thereby prevent the overshoot in the rotation speed of the internal-combustion engine.