Patent ID: 6787931
Filing Date: 2004-09-07
Classification: F02N

Abstract:
A starter generator for an internal combustion engine that operates as an electric motor for starting said internal combustion engine when said internal combustion engine is started, and operates as a generator after said internal combustion engine is started, comprising:a magnet rotor mounted to a crankshaft of said internal combustion engine; a stator having a polyphase first armature coil and a polyphase second armature coil; a first battery and a second battery; a first driver provided between said first armature coil and said first battery, and a second driver provided between said second armature coil and said second battery; an inverter that converts a voltage of said first battery and a voltage of said second battery into an AC voltage; and a controller that controls said first driver, said second driver, and said inverter, wherein each driver includes: a polyphase rectifier circuit that is constituted by a bridge circuit of diodes, and rectifies an AC voltage induced in the corresponding armature coil to supply the AC voltage to the corresponding battery; and a polyphase switch circuit that is constituted by a bridge circuit of switch elements, each switch element being connected in anti-parallel to the corresponding diode that forms said polyphase rectifier circuit, said controller includes: a driver control unit that flows drive currents to said first armature coil and said second armature coil from said first battery and said second battery through the polyphase switch circuits in said first driver and said second driver, respectively, so as to rotate said magnet rotor in a direction of starting said internal combustion engine, when said internal combustion engine is started, and controls the polyphase switch circuits in said first driver and said second driver so as to keep, at a value equal to or less than a set value, DC voltages supplied to said first battery and said second battery from said first armature coil and said second armature coil through the polyphase rectifier circuits in said first driver and said second driver, after said internal combustion engine is started; and an inverter control unit that controls said inverter so as to output an AC voltage at a desired frequency from said inverter, and said first battery and said second battery are connected in series or in parallel according to an effective value of the AC voltage output from said inverter and are connected between DC input terminals of said inverter.