Parallel generator power system

• US 6,639,331 B2
• Filed: 11/30/2001
• Issued: 10/28/2003
• Est. Priority Date: 11/30/2001
• Status: Active Grant

• Current Assignee: ONAN Corporation (Cummins Incorporated)
• Original Assignee: ONAN Corporation (Cummins Incorporated)
• Inventors: Schultz, Mark H.
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): Polk, Sharon A.
• Application Number:
  US09/997,481
• Publication Number:
  US 20030102716A1
• Time in Patent Office: 697 Days
• Field of Search: 307/80, 307/81, 307/84, 307/87, 307/85, 307/86, 307/19, 307/153, 700/9, 700/11, 700/12, 700/297
• US Class Current: 307/84
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02P 9/08 Control of generator circuit during starting or stopping of driving means, e.g. for initiating excitation

Abstract

A system for connecting one of a plurality of parallel connected generator sets to a common bus. The system includes a separate module associated with each of the plurality of generator sets. When a control module receives a ready-to-load signal from the generator set, each of the control modules performs a similar connection method which determines which of the modules will send a first-start command to its associated generator.

Claims

1. A power system comprising:

two generator sets connected in parallel to a common bus, each of the two generator sets having a switch between an output of each of the generator sets and the bus; and

two modules, wherein each of the two modules is associated with one of the two generator sets and each of the two modules is configured to receive a signal from that module'"'"'s associated generator set when that module'"'"'s associated generator set is ready to energize the bus and to output a signal which allows that module'"'"'s associated generator set to connect to the bus, wherein the two modules are connected to each other;

wherein the two modules are similarly configured such that when each of the two modules receives the signal that the module'"'"'s associated generator set is ready to energize the bus at substantially the same time, each of the two modules performs a similar method which provides that only one of the two modules is permitted to send the signal which allows that module'"'"'s associated generator set to connect to the bus.

2. The power system of claim 1, wherein a result of each of the similar methods performed by each module is not pre-determinable.

3. The power system of claim 1, wherein a result of each of the similar methods performed by each module is randomly decided.

4. The power system of claim 1, wherein each of the two modules includes a randomly controlled transistor and the two modules are connected together such that each module knows whether the transistor of the other module is in an on state or an off state.

5. The power system of claim 4, wherein the method includes each module monitoring a state of its transistor and a state of the other module'"'"'s transistor and when its transistor is in an on state and the other module'"'"'s transistor is in an off state, the module is allowed to send the signal which allows that module'"'"'s associated generator set to connect to the bus.

6. A system for connecting one of a plurality of parallel connected generator sets to a common bus, the system comprising:

a plurality of separate modules, each of the plurality of separate modules being associated with one of the plurality of generator sets, wherein each separate module is configured to communicate with the other separate modules such that if more than one of the plurality of generator sets is ready to energize the common bus, each of the separate modules associated with the more than one generator sets communicate with each other to randomly decide which generator set will be allowed to connect to the common bus first.

7. The system of claim 6, wherein each of the plurality of separate modules includes a randomly controlled transistor and each of the plurality of separate modules knows whether the transistor of the other separate modules is in an on or off state.

8. The power system of claim 7, wherein each of the plurality of separate modules monitors a state of its transistor and a state of the other separate modules transistors and when its transistor is in an on state and the other separate modules transistors are in an off state, that module is allowed to send a signal which allows that module'"'"'s associated generator set to connect to the bus.

9. A module connected to a generator for controlling a connection of the generator to a bus, the module comprising:

an input for receiving a signal indicating that the generator is ready to energize the bus;

an output for sending a signal allowing the generator to connect to the bus;

a second input for connecting the module to a second module which is connected to a second generator; and

a signal processor which is configured to monitor the second input and to send the signal allowing the generator to connect to the bus when the signal processor reaches a first-start state before the second module.

10. The module of claim 9, wherein the module includes a first transistor which is turned off and on by the signal processor for random time periods, and wherein the signal processor monitors the second input by sensing whether a second transistor in the second module is in an on state, wherein when the first transistor is in an on state and the second transistor is in an off state, the module sends the signal allowing the generator to connect to the bus.

11. The module of claim 9, wherein the module includes a first opto coupler, a second opto coupler, and a transistor, which are connected to the signal processor and to the second input and are configures so that when the transistor is ON, the first opto coupler is ON and the second opto coupler is OFF, the signal processor sends the signal allowing the generator to connect to the bus.

12. The module of claim 9, wherein the module and the second module have substantially equivalent configurations such that it is not pre-determinable which module will reach the first-start state first.

13. A method of connecting one of a plurality of parallel connected generator sets to a common bus, the method comprising:

providing a plurality of substantially functionally equivalent connection modules, each of the plurality of connection modules associated with one of the plurality of generator sets, each of the plurality of connection modules configured to send a signal to its associated generator set when the connection module reaches a first-start state; and

connecting each of the plurality of connection modules to the connection module'"'"'s one or two neighboring connection modules to allow the connection modules to communicate with each other.

14. The method of claim 13, wherein when two or more of the plurality of connection modules receive a signal that their associated generator sets are ready to energize the bus at substantially the same time, the connection modules perform similar methods to determine which connection module will be allowed to send the signal to its associated generator set.

15. The method of claim 14, wherein a result of the methods of the two modules is not pre-determinable.

16. The method of claim 14, wherein a result of the methods of the two modules is randomly decided.

17. A method of connecting one of a plurality of parallel connected generator sets to a common bus, the method comprising:

providing a plurality of substantially equivalent modules, wherein each of the plurality of modules is associated with one of the plurality of parallel connected generator sets;

determining which one of the plurality of substantially equivalent modules reaches a first-start state;

directing the one module which reaches the first-start state to send a signal to its associated generator set to allow the generator set to load to the bus; and

inhibiting the rest of the plurality of modules from sending a signal to their associated generator sets.