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

• US 20070114976A1
• Filed: 11/13/2006
• Published: 05/24/2007
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Asada, Tadatoshi, Tsuzuki, Tomomi, Inokuchi, Takatoshi
• Granted Patent: US 7,405,541 B2
• Time in Patent Office: Days
• US Class Current: 322/28
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/243 with on/off action
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/006 Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

According to the present invention, there is provided a control apparatus for an automotive alternator which includes a switch, a target voltage setter, a voltage regulator, and a disconnection detector. The switch is configured to be selectively turned on and off so as to intermittently excite the alternator. The target voltage setter works to set a target voltage. The voltage regulator works to regulate an output voltage of the alternator to the target voltage through controlling on/off operation the switch. The disconnection detector works to detect disconnection between the alternator and an on-board battery to be charged by the alternator. The disconnection detector is configured to detect the disconnection, when the target voltage is changed from a lower value to a higher value, based on a time required for the voltage regulator to bring the output voltage of the alternator from the lower value to the higher value.

Claims

1. 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 time required for the voltage regulator to bring the output voltage of the alternator from the lower value to the higher value.

2. The control apparatus as set forth in claim 1, wherein the disconnection detector is configured to compare the time with a predetermined threshold and determine that the battery is disconnected from the alternator when the time is shorter than the predetermined threshold.

3. The control apparatus as set forth in claim 2, further comprising a speed detector that works to detect rotational speed of the alternator, wherein the disconnection detector is configured to correct the predetermined threshold according to the rotational speed detected by the speed detector, compare the time with the corrected threshold, and determine that the battery is disconnected from the alternator when the time is shorter than the corrected threshold.

4. The control apparatus as set forth in claim 2, further comprising a temperature detector that works to detect temperature of the alternator, wherein the disconnection detector is configured to correct the predetermined threshold according to the temperature detected by the temperature detector, compare the time with the corrected threshold, and determine that the battery is disconnected from the alternator when the time is shorter than the corrected threshold.

5. The control apparatus as set forth in claim 2, wherein the disconnection detector is configured to correct the predetermined threshold according to a duty cycle of the switch before the change in the target voltage, compare the time with the corrected threshold, and determine that the battery is disconnected from the alternator when the time is shorter than the corrected threshold.

6. The control apparatus as set forth in claim 1, further comprising a warning device that works to warn of the disconnection between the alternator and the battery in response to detection of the disconnection by the disconnection detector.

7. 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.

8. The control apparatus as set forth in claim 7, wherein the disconnection detector is configured to compare the difference with a predetermined threshold and determine that the battery is disconnected from the alternator when the difference is less than the predetermined threshold.

9. The control apparatus as set forth in claim 8, further comprising a speed detector that works to detect rotational speed of the alternator, wherein the disconnection detector is configured to correct the predetermined threshold according to the rotational speed detected by the speed detector, compare the difference with the corrected threshold, and determine that the battery is disconnected from the alternator when the difference is less than the corrected threshold.

10. The control apparatus as set forth in claim 8, further comprising a temperature detector that works to detect temperature of the alternator, wherein the disconnection detector is configured to correct the predetermined threshold according to the temperature detected by the temperature detector, compare the difference with the corrected threshold, and determine that the battery is disconnected from the alternator when the difference is less than the corrected threshold.

11. The control apparatus as set forth in claim 8, wherein the disconnection detector is configured to correct the predetermined threshold according to the duty cycle of the switch before the change in the target voltage, compare the difference with the corrected threshold, and determine that the battery is disconnected from the alternator when the difference is less than the corrected threshold.

12. The control apparatus as set forth in claim 7, further comprising a warning device that works to warn of the disconnection between the alternator and the battery in response to detection of the disconnection by the disconnection detector.

13. 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.

14. The electric power generation system as set forth in claim 13, wherein the disconnection detector of the second control apparatus is configured to compare the difference with a predetermined threshold and determine that the battery is disconnected from the alternator when the difference is less than the predetermined threshold.

15. The electric power generation system as set forth in claim 13, wherein the second control apparatus further includes a warning device that works to warn of the disconnection between the alternator and the battery in response to detection of the disconnection by the disconnection detector.

16. 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.

17. The electric power generation system as set forth in claim 16, wherein the disconnection detector of the second control apparatus is configured to compare the difference with a predetermined threshold and determine that the battery is disconnected from the alternator when the difference is less than the predetermined threshold.

18. The electric power generation system as set forth in claim 16, wherein the second control apparatus further includes a warning device that works to warn of the disconnection between the alternator and the battery in response to detection of the disconnection by the disconnection detector.