Power supply system

• US 5,675,238 A
• Filed: 11/16/1995
• Issued: 10/07/1997
• Est. Priority Date: 11/30/1994
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Asao, Yoshihito
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US08/558,469
• Time in Patent Office: 691 Days
• Field of Search: 322/25, 322/26, 322/27, 322/28
• US Class Current: 322/28
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries

Abstract

A power supply system equipped with a power generating unit including an alternating-current generator and a rectifier for rectifying the generated output of the alternating-current generator. In addition, a switching relay is provided between a low-voltage load and a high-voltage load for selectively supplying the generated output from the power generating unit to one of the low-voltage load and high-voltage load. A field current control unit controls a field current flowing into a field winding of an AC generator and a high-voltage load control unit controls a switching operation of the switching relay and further controls the field current control unit in accordance with a state of the high-voltage load. The high-voltage load control unit operates the power generating unit through the field current control unit in switching between the low-voltage load and the high-voltage load so that the generated output is applied to the switching relay, thus removing oxide films on a surface of the switching relay to ensure the conductivity in the switching relay.

Claims

1. A power supply system comprising:

a power generating unit including an alternating-current generator for generating an alternating-current output, and a rectifier connected with said alternating-current generator for rectifying said generated output of said alternating-current generator;

switching means provided between a low-voltage load and a high-voltage load for selectively supplying said generated output from said power generating unit via a first terminal to one of said low-voltage load via a second terminal and said high-voltage load via a third terminal;

first control means connected to a field winding of said alternating-current generator for controlling a field current flowing into said field winding;

detection means for detecting a state of said high-voltage load; and

second control means connected with said switching means, said first control means and said detection means for controlling a switching operation of said switching means and further for controlling said first control means in accordance with the state of said high-voltage load, said second control means operating said power generating unit through said first control means in switching between said low-voltage load and said high-voltage load so that the generated output is applied to said switching means, thereby generating an arc between said first terminal and one of said second and third terminals.

2. A power supply system as set forth in claim 1, wherein said second control means controls said switching means to operate when a voltage drop in said switching means exceeds a predetermined value.

3. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means when a time period said switching means is connected to at least one of said low-voltage load and said high-voltage load becomes longer than a predetermined time period.

4. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means when the number of times said switching means switches to at least one of said low-voltage load and said high-voltage load exceeds a predetermined value.

5. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means by decreasing the field current flowing into said field winding of said alternating-current generator by a predetermined quantity.

6. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means by decreasing the field current flowing into said field winding of said alternating-current generator by a predetermined quantity when a voltage drop in said switching means exceeds a predetermined value.

7. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means by decreasing the field current flowing into said field winding of said alternating-current generator by a predetermined quantity when a time period during which said switching means is connected to at least one of said low-voltage load and said high voltage load becomes longer than a predetermined time period.

8. A power supply system as set forth in claim 1, wherein said second control means performs the switching operation of said switching means by decreasing the field current flowing into said field winding of said alternating-current generator by a predetermined quantity when the number of times said switching means switches to at least one of said low-voltage load and said high-voltage load exceeds a predetermined value.

9. A power supply system as set forth in claim 1, wherein said first control means comprises a field current control circuit and said second control means comprises a high-voltage load control unit.

10. A power supply system as set forth in claim 1, wherein said arc destroys a nonconductive film on said one of said second and third terminals of said switching means.

11. A power supply system as set forth in claim 1, wherein said nonconductive film is an oxide film.

12. A power supply system as set forth in claim 1, wherein said second control means operates said power generating unit through said low-voltage load for a predetermined amount of time, thereby preventing damage to said one of said second and third terminals.

13. A power supply system as set forth in claim 2, wherein said voltage drop in said switching means is a voltage drop between said first terminal and one of said second and third terminals.

14. A power supply system comprising:

a power generating unit including an alternating-current generator for generating an alternating-current output, and a rectifier connected with said alternating-current generator for rectifying said generated output of said alternating-current generator, wherein said alternating-current generator includes a field winding;

a switching unit, provided between a low-voltage load and a high-voltage load and having first through third terminals, for selectively supplying said generated output from said power generating unit via the first terminal to one of said low-voltage load via the second terminal and said high-voltage load via the third terminal;

a first control unit connected to the field winding of said alternating-current generator for controlling a field current flowing into said field winding;

a detector for detecting a state of said high-voltage load and outputting a high-voltage load detection signal based on the detected state; and

a second control unit connected to said switching unit, said first control unit and said detector, wherein in response to said high-voltage load detection signal said second control unit controls said first control unit to operate said power generating unit to generate a power output so that the generated power output is applied to said switching unit and controls a switching operation of said switching unit to switch the generated power output applied to said switching unit between said low-voltage load and said high-voltage load, thereby generating an arc between said first terminal and one of said second and third terminals.

15. A power supply system as set forth in claim 14, wherein said second control unit controls said switching unit to operate when a voltage drop in said switching unit exceeds a predetermined value.

16. A power supply system as set forth in claim 15, wherein said voltage drop in said switching unit is a voltage drop between said first terminal and one of said second and third terminals.

17. A power supply system as set forth in claim 14, wherein said second control unit performs the switching operation of said switching unit when a time period said switching unit is connected to at least one of said low-voltage load and said high-voltage load becomes longer than a predetermined time period.

18. A power supply system as set forth in claim 14, wherein said second control unit performs the switching operation of said switching unit when the number of times said switching unit switches to at least one of said low-voltage load and said high-voltage load exceeds a predetermined value.

19. A power supply system as set forth in claim 14, wherein said first control unit comprises a field current control circuit and said second control unit comprises a high-voltage load control unit.