Control apparatus for automotive alternator having capability of reliably detecting disconnection between alternator and battery

A control apparatus for an automotive alternator which is electrically connected with an on-board battery to charge the battery, the control apparatus comprising:

• a switch configured to be selectively turned on and off so as to intermittently excite the alternator;
• a target voltage setter working to set a target voltage;
• a voltage regulator working to regulate an output voltage of the alternator to the target voltage set by the target voltage setter through controlling on/off operation the switch;
• and
• a disconnection detector working to detect disconnection between the alternator and the battery, the disconnection detector being configured to detect the disconnection, when the target voltage is changed from a lower value to a higher value, based on a difference in duty cycle of the switch between after and before the change in the target voltage.

An electric power generation system for a vehicle comprising:

• an automotive alternator working to generate electric power, the alternator being electrically connected with an on-board battery to charge the battery with the electric power;
• a first control apparatus;
• and
• a second control apparatus that communicates with the first control apparatus,
• wherein the first control apparatus includes:
• a switch configured to be selectively turned on and off so as to intermittently excite the alternator;
• a target voltage setter working to receive a command signal from the second control apparatus and set a target voltage according to the command signal;
• a voltage regulator working to regulate an output voltage of the alternator to the target voltage through controlling on/off operation the switch;
• and
• a duty-cycle signal transmitter working to transmit to the second control apparatus a duty-cycle signal indicative of duty cycle of the switch, and
• wherein the second control apparatus includes:
• a target voltage determiner working to determine the target voltage;
• a command signal transmitter working to transmit to the first control apparatus the command signal which indicates the target voltage determined by the target voltage determiner;
• a duty-cycle signal receiver working to receive the duty-cycle signal from the first control apparatus;
• and
• a disconnection detector working to detect disconnection between the alternator and the battery, the disconnection detector being configured to determine, when the target voltage is changed from a lower value to a higher value, a difference in duty cycle of the switch between after and before the change in the target voltage based on the duty-cycle signal received by the duty-cycle signal receiver and detect the disconnection based on the determined difference.

An electric power generation system for a vehicle comprising:

• an automotive alternator working to generate electric power, the alternator being electrically connected with an on-board battery via a conducting wire to charge the battery with the electric power, the conducing wire being also electrically connected to electrical load;
• a first control apparatus;
• and
• a second control apparatus that communicates with the first control apparatus,
• wherein the first control apparatus includes:
• a switch being configured to be selectively turned on and off so as to intermittently excite the alternator;
• a voltage regulator working to regulate an output voltage of the alternator to a predetermined value through controlling on/off operation the switch;
• and
• a duty-cycle signal transmitter working to transmit to the second control apparatus a duty-cycle signal indicative of duty cycle of the switch, and
• wherein the second control apparatus includes:
• a load change detector working to detect a change in the electrical load;
• a duty-cycle signal receiver working to receive the duty-cycle signal from the first control apparatus;
• and
• a disconnection detector working to detect disconnection between the alternator and the battery, the disconnection detector being configured to determine, when the change in the electrical load is detected by the load change detector, a difference in duty cycle of the switch between after and before the change in the electrical load based on the duty-cycle signal received by the duty-cycle signal receiver and detect the disconnection based on the determined difference.