System and method for controlling electric load and battery charge in a vehicle

• US 6,924,621 B2
• Filed: 05/07/2002
• Issued: 08/02/2005
• Est. Priority Date: 05/07/2002
• Status: Expired due to Term

• Current Assignee: C.E. Niehoff & Co.
• Original Assignee: C.E. Niehoff & Co.
• Inventors: Jabaji, Shadi, Jabaji, Issam
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): Luk, Lawrence
• Application Number:
  US10/140,901
• Publication Number:
  US 20030210014A1
• Time in Patent Office: 1,183 Days
• Field of Search: 320/123, 320/117, 320/116, 320/127, 320/132, 320/133, 320/104, 320/135, 320/136, 324/427, 324/430
• US Class Current: 320/123
• CPC Class Codes: H02J 1/082 Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/1492 by means of controlling devices between the generator output and the battery
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A load and battery charge device in a vehicle electrical system controllably disconnects a battery or other stored energy source from the electrical system when the battery state causes the system voltage to operate below a desired threshold. The device filters generator ripple voltage during batteryless operation to maintain an acceptable ripple voltage. The load and battery control device operates to recharge the battery that is disconnected from the vehicle electrical system at a controlled voltage independent of the vehicle electrical system voltage. The load and battery control device controls the rate of battery recharge so as to avoid overburdening the vehicle electrical system and then reconnects the battery to the vehicle electrical system once the battery voltage has reached a minimum threshold.

Claims

1. A system for monitoring vehicle electrical load and controlling battery charge comprising:

a generator electrically coupled with a vehicle electrical system;

a battery electrically coupled with the vehicle electrical system via a battery disconnect switch; and

a control circuit in communication with the battery disconnect switch, wherein the control circuit is configured to control the battery disconnect switch to disconnect the battery from the vehicle electrical system when a voltage output of the generator is below a desired threshold, and wherein the control circuit is configured to control the battery disconnect switch to reconnect the battery to the vehicle electrical system when a voltage of the battery is above a desired battery voltage threshold, and wherein the control circuit is configured to regulate a battery charging voltage with excess generator capacity while the battery is disconnected from the vehicle electrical system.

2. The system of claim 1, wherein the control circuit further comprises a battery charging circuit.

3. The system of claim 2, wherein the battery charging circuit comprises a silicon controlled rectifier.

4. The system of claim 3, wherein the control circuit is configured to automatically adjust a duty cycle of the silicon controlled rectifier to adjust a rate of battery recharge.

5. The system of claim 4, wherein the control circuit comprises a voltage sense input and wherein the control circuit is configured to adjust the duty cycle of the silicon controlled rectifier in response to a generator voltage detected at the voltage sense input.

6. The system of claim 2, wherein the control circuit is configured to adjust a rate of battery recharge via the battery charging circuit.

7. The system of claim 2 wherein the control circuit is adapted to switchably connect a trickle charge line in communication with the battery to power produced by the generator while the battery is disconnected from the vehicle electrical system.

8. The system of claim 1, wherein the generator comprises an alternator.

9. The system of claim 8 wherein the alternator comprises a three phase alternator and the control circuit further comprises a battery charging circuit switchably connecting a trickle charge line in communication with the battery to a single phase output of the three phase alternator.

10. The system of claim 1, wherein the control circuit comprises a ripple filter.

11. The system of claim 10 wherein the ripple filter comprises an input coupled to the voltage output of the generator and an output coupled to the vehicle electrical system, wherein a ripple voltage of the voltage output is controlled when the battery is disconnected from the vehicle electrical system.

12. The system of claim 11, wherein the ripple voltage is reduced when the battery is disconnected from the vehicle electrical system.

13. A control circuit for controlling a rate of recharge of a battery in a vehicle electrical system, wherein the vehicle electrical system is powered by an alternator during vehicle operation, the control circuit comprising:

a battery disconnect switch disposed between the battery and the vehicle electrical system operable to electrically disconnect the battery from the vehicle electrical system;

a battery charging circuit in electrical communication with the battery and the alternator;

a processor in communication with the battery disconnect switch and the battery charging circuit; and

programming code operable on the processor to disconnect the battery from the vehicle electrical system with the battery disconnect switch in response to an alternator voltage output below a threshold value, and to control a recharge rate for the battery with the battery charging circuit while the battery is disconnected from the vehicle electrical system.

14. The control circuit of claim 13, wherein the battery charging circuit comprises a silicon controlled rectifier.

15. A The control circuit of claim 13, wherein the battery disconnect switch comprises a relay.

16. The system of claim 13, wherein the control circuit further comprises a ripple filter having an input coupled to the alternator voltage output and an output coupled to the vehicle electrical system, wherein a ripple voltage of the alternator voltage output is reduced when the battery is disconnected from the vehicle electrical system.

17. A method for controlling electric load and battery charge in a vehicle electrical system, the method comprising:

(a) disconnecting a rechargeable source of stored energy from the vehicle electrical system if a voltage at the vehicle electrical system falls below a first threshold;

(b) controllably charging the rechargeable source of stored energy with energy from a generator in the vehicle electrical system such that an operating voltage of the vehicle electrical system remains above an operating voltage threshold; and

(c) reconnecting the rechargeable source of stored energy to the vehicle electrical system when a voltage at the rechargeable source of stored energy is above a desired voltage threshold, wherein the vehicle electrical system operates with energy from the generator while the rechargeable source of stored energy is disconnected and being recharged.

18. The method of claim 17, wherein (a) comprises sensing the output voltage of the generator, comparing the output voltage of the generator to the first threshold, and operating a relay to disconnect the rechargeable source of stored energy if the sensed output voltage of the generator is less than the first threshold.

19. The method of claim 17, wherein (b) further comprises controllably charging the rechargeable source of stored energy by adjusting a duty cycle of a switchable device connecting the rechargeable source of stored energy to the generator.

20. The method of claim 19, wherein the switchable device comprises a silicon controlled rectifier.

21. The method of claim 17, wherein the rechargeable source of stored energy comprises a battery.

22. The method of claim 17, wherein (b) further comprises signaling a warning to a vehicle operator while the source of stored of stored energy is disconnected from the vehicle electrical system.

23. The method of claim 17, wherein (c) further comprises reconnecting the rechargeable source of stored energy to the vehicle electrical system when a voltage at the rechargeable source of stored energy is maintained at a different voltage level than the operating voltage of the vehicle electrical system above a desired voltage threshold.

24. The method of claim 17, wherein the generator comprises an alternator having a three phase AC output and (b) further comprises controllably charging the source of stored energy with at least one phase of the three phase AC output of the alternator.

25. A control circuit for controlling a rate of recharge of a battery in a vehicle electrical system and maintaining separate load and trickle charge voltage levels, wherein the vehicle electrical system is powered by a generator during vehicle operation, the control circuit comprising:

a battery disconnect switch disposed between the battery and the vehicle electrical system operable to electrically disconnect the battery from the vehicle electrical system and to reconnect the battery to the vehicle electrical system;

a battery charging circuit in electrical communication with the battery and the generator;

a processor in communication with the battery disconnect switch and the battery charging circuit; and

programming code operable on the processor to disconnect the battery from the vehicle electrical system with the battery disconnect switch in response to a generator voltage output below a threshold value, to control a recharge rate for the battery with the battery charging circuit while the battery is disconnected from the vehicle electrical system, and to reconnect the battery to the vehicle electrical system in when the generator voltage output is above the threshold value.

26. The system of claim 25 wherein the generator comprises an alternator.

27. The system of claim 26 wherein the control circuit further comprises a ripple filter.

28. The system of claim 26 wherein the ripple filter comprises an input coupled to the alternator voltage output and an output coupled to the vehicle electrical system, wherein a ripple voltage of the alternator output voltage is controlled when the battery is disconnected from the vehicle electrical system.