Overvoltage protection system and method

• US 9,425,608 B2
• Filed: 12/20/2011
• Issued: 08/23/2016
• Est. Priority Date: 12/20/2011
• Status: Active Grant

• Current Assignee: Discovery Energy LLC
• Original Assignee: Kohler Company
• Inventors: Kleczewski, Michael R., Thakur, Awadhesh K.
• Primary Examiner(s): PELTON, NATHANIEL R
• Application Number:
  US13/331,857
• Publication Number:
  US 20130154546A1
• Time in Patent Office: 1,708 Days
• Field of Search: 320/107, 320/134
• US Class Current: 1/1
• CPC Class Codes: H02H 3/202 for dc systems
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/1492 by means of controlling devices between the generator output and the battery
• CPC Class Codes: H02J 7/243 with on/off action
• CPC Class Codes: H02J 7/2437 using thyristors or triacs as final control devices
• 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

An electrical system for use with an alternator that supplies electrical power, an internal combustion engine including such an electrical system, and related methods of operation are disclosed. In one example embodiment, such an electrical system includes a first circuit portion configured to govern whether the power is communicated from the alternator system to a terminal associated with a battery and/or a load, and a second circuit portion configured to determine whether a voltage is elevated above a predetermined threshold and to provide a first signal upon determining that the voltage is so elevated. The electrical system also includes a third circuit portion coupled at least indirectly to the other two circuit portions. The third circuit portion is configured to provide a second signal upon receiving the first signal, the second signal being configured to cause the first circuit portion to cease allowing communication of the power to the terminal.

Claims

1. An electrical system for use with an alternator system that supplies electrical power, the electrical system comprising:

a first circuit portion configured to govern whether the electrical power is communicated from the alternator system to a terminal associated with both of a battery and a load;

a second circuit portion configured to determine whether a voltage is elevated above a predetermined threshold and to provide a first signal upon determining that the voltage is elevated above the predetermined threshold, wherein the voltage is either a first voltage at the terminal or a second voltage based at least indirectly upon the first voltage; and

a third circuit portion coupled at least indirectly to each of the first and second circuit portions, wherein the third circuit portion includes at least one comparator circuit portion configured to make a determination as to whether an additional voltage is below or equal to a charge set point,

wherein the third circuit portion is connected electrically at least indirectly in between the second and first circuit portions and configured to provide a second signal for receipt by the first circuit portion upon receiving the first signal from the second circuit portion,

wherein the third circuit portion also is configured to provide the second signal for receipt by the first circuit portion upon the determination being made by the at least one comparator circuit portion that the additional voltage is not below or equal to the charge set point, and

wherein the second signal is additionally configured to cause the first circuit portion to cease allowing communication of the electrical power to the terminal.

2. The electrical system of claim 1, wherein the first circuit portion includes a silicon-controlled rectifier or thyristor that can be switched to conductive and non-conductive operational states, and wherein the second circuit portion includes at least one first transistor-type device having a first operational status that is switched upon the determining that the voltage is elevated above the predetermined threshold.

3. The electrical system of claim 2, wherein the at least one first transistor-type device includes a voltage-controlled device and the first operational status of the voltage-controlled device is switched to a conductive status upon the determining that the voltage is above the predetermined threshold.

4. The electrical system of claim 2, wherein the third circuit portion includes at least one second transistor-type device, and wherein the at least one second transistor-type device has a second operational status that is switched when the first operational status of the at least one first transistor-type device is switched.

5. The electrical system of claim 4, wherein the at least one first transistor-type device includes a N-Channel metal-oxide semiconductor field-effect transistor (MOSFET), wherein the at least one second transistor-type device includes a first bipolar junction transistor (BJT), and wherein the second operational status is switched to a non-conductive status when the first operational status is switched to a conductive status.

6. The electrical system of claim 1, wherein one or more of the first circuit portion, the third circuit portion, and a fourth circuit portion are configured to operate to provide either half wave or full wave rectification of the electrical power and to communicate the electrical power as rectified to the terminal, in the absence of the voltage being elevated above the predetermined threshold and when the additional voltage based at least indirectly thereon is below or equal to the charge set point.

7. The electrical system of claim 1, wherein the second circuit portion is configured to operate so that, upon expiration of a predetermined time delay following a first overvoltage event, the first signal is returned to a normal operation level.

8. The electrical system of claim 7, wherein the second circuit portion includes a resistor and a capacitor, and the predetermined time delay is determined at least in part based upon a resistance value of the resistor and a capacitance value of the capacitor.

9. The electrical system of claim 8, wherein the capacitor is charged at least in part as a result of energy received due to the overvoltage event, and wherein the second circuit portion is configured to provide an automatic reset capability.

10. The electrical system of claim 7, wherein the second circuit portion is additionally configured to further defer returning of the first signal to the normal operation level by an amount of time equaling either the predetermined time delay or an additional predetermined time delay following an additional overvoltage event that occurs subsequent to the first overvoltage event but prior to the expiration of the predetermined time delay following the first overvoltage event.

11. The electrical system of claim 1, further comprising additional circuit components that provide diagnostic indicators, wherein the additional circuit components include a fourth circuit portion that is configured to output an indication as to whether the system is currently operating in a normal manner as a rectifier regulator, and further include a fifth circuit portion that is configured to output an additional indication as to whether the system is currently shut down due to an overvoltage event having occurred.

12. An internal combustion engine that includes the electrical system and the alternator system of claim 1, wherein the engine is either a small off-road engine or a non-road engine.

13. The electrical system of claim 1, wherein the electrical system is configured so that, when the voltage that is elevated above the predetermined threshold is provided from the alternator system or from one or more other external sources connected to the electrical system, the electrical system operates to protect one or more electrical components on a system power line by isolating the alternator system.

14. The electrical system of claim 1, wherein the second circuit portion includes a first Zener diode by which the voltage is determined to be elevated above the predetermined threshold.

15. The electrical system of claim 14, wherein the third circuit portion includes a second Zener diode by which the additional voltage based at least indirectly thereon is below or equal to the charge set point, wherein the third circuit portion includes a first BJT transistor coupled at least indirectly to the second Zener diode, and wherein the fourth circuit portion includes at least one additional BJT transistor and provides a trigger signal to the first circuit portion.

16. The electrical system of claim 15, wherein the second signal is provided at least indirectly from the first BJT transistor when the first BJT transistor ceases conducting, and wherein a fourth circuit portion includes a resistor and capacitor coupled in parallel that form a filter that serves to bias a gate of a silicon controlled rectifier of the first circuit portion.

17. A method of operating an electrical system of an engine having an alternator system that is configured to supply alternating current (AC) power to a remainder of the electrical system, the method comprising:

rectifying the AC power supplied by the alternator system and communicating the rectified AC power to a terminal at which are coupled both of a battery and a load, wherein the electrical system includes a silicon-controlled rectifier employed for performing the rectifying, and wherein the electrical system additionally includes a transistor device that at least indirectly influences operation of the silicon-controlled rectifier;

experiencing an overvoltage event at which a first voltage exceeds a threshold, wherein the first voltage is either a terminal voltage at the terminal or an other voltage based at least indirectly upon the terminal voltage;

causing the communicating of the rectified AC power to the terminal to cease, at least partly in response to the experiencing of the overvoltage event, wherein the electrical system is configured so that, when the first voltage exceeding the threshold is provided from the alternator system or from one or more other external sources connected to the electrical system, the electrical system operates to protect one or more electrical components on a system power line by isolating the alternator system;

charging a capacitor at least in part as a result of energy received due to the overvoltage event; and

delaying a reestablishment of the communicating of the rectified AC power to the terminal until at least a predetermined time period has elapsed since the overvoltage event, wherein the predetermined time period is based at least in part upon a resistance of a resistor and a capacitance of the capacitor that discharges through the resistor following a conclusion of the overvoltage event, wherein the reestablishment of the communicating of the rectified AC power occurs upon the capacitor being sufficiently discharged so as to result in a switching of a status of the transistor device, and

wherein, prior to the overvoltage event, the communicating of the rectified AC power additionally ceases during a time period in response to a second voltage exceeding a battery charge set point and subsequently is reestablished.

18. The method of claim 17, further comprising one or more of:

(a) filtering out signal components that can disrupt proper operation of the silicon controlled rectifier employed for performing the rectifying; and

(b) providing one or more indications of a status regarding one or both of (i) whether the communicating of the rectified AC power is proceeding normally, and (ii) whether the communicating of the rectified AC power has ceased due to the overvoltage event.

19. An electrical system for use with an alternator system that supplies electrical power, the electrical system comprising:

a first circuit portion configured to govern whether the electrical power is communicated from the alternator system to a terminal associated with both of a battery and a load;

a second circuit portion configured to determine whether a voltage is elevated above a predetermined threshold and to provide a first signal upon determining that the voltage is elevated above the predetermined threshold such that an overvoltage condition has occurred, wherein the voltage is either a first voltage at the terminal or a second voltage based at least indirectly upon the first voltage; and

a third circuit portion coupled at least indirectly to each of the first and second circuit portions, wherein the third circuit portion includes at least one comparator circuit portion configured to make a determination as to whether an additional voltage is below or equal to a charge set point,

wherein the third circuit portion is configured to provide a second signal for receipt by the first circuit portion upon receiving the first signal from the second circuit portion,

wherein the third circuit portion also is configured to provide the second signal for receipt by the first circuit portion upon the determination being made by the at least one comparator circuit portion that the additional voltage is not below or equal to the charge set point,

wherein the second signal is additionally configured to cause the first circuit portion to cease allowing communication of the electrical power to the terminal, and

wherein the electrical system is configured so that, when the voltage that is elevated above the predetermined threshold is provided from the alternator system or from one or more other external sources connected to the electrical system, the electrical system operates to protect one or more electrical components on a system power line by isolating the alternator system.

20. The electrical system of claim 19, wherein the third circuit portion is connected electrically at least indirectly in between the second and first circuit portions, and wherein the second circuit portion includes a first Zener diode by which the voltage is determined to be elevated above the predetermined threshold.