Electric power generation system with multiple inverters

• US 7,687,929 B2
• Filed: 06/01/2007
• Issued: 03/30/2010
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Cummins Power Generation IP, Inc.
• Original Assignee: Cummins Power Generation IP, Inc.
• Inventors: Fattal, Souren G.
• Primary Examiner(s): GONZALEZ, JULIO CESAR
• Application Number:
  US11/809,745
• Publication Number:
  US 20080157540A1
• Time in Patent Office: 1,033 Days
• Field of Search: 290/40.C, 290/4.R, 290/4.A, 290/4.C, 322/44, 322/59
• US Class Current: 290/40.00C
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/30 for monitoring or controlling fuel cells
• CPC Class Codes: B60L 58/33 by cooling
• CPC Class Codes: H02P 2101/45 for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• CPC Class Codes: H02P 9/307 more than one voltage output
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

An apparatus includes a vehicular electric power generation system comprising a variable speed internal combustion engine, a first variable speed electric power generator driven by the engine, a second variable speed electric power generator driven by the engine, a first inverter to receive electric power from the first generator a provide a first controlled electric output, a second inverter to receive electric power from the second generator and provide a second controlled electric output, and a controller coupled to the engine. The controller is responsive to variation in electrical loading of the first inverter and the second inverter and a degree of electrical load imbalance between the first inverter and second inverter to provide an engine control signal. The engine is responsive to the one more engine control signals to change rotational operating speed to adjust for the variation in electrical loading and the degree of electrical load imbalance.

Claims

1. A method, comprising:

operating a vehicular electrical power generation system including a variable speed internal combustion engine, a first variable speed electric power generator, a second variable speed electric power generator, a first inverter coupled to the first generator, and a second inverter coupled to the second generator;

driving the first generator and the second generator with the internal combustion engine operating at a first speed to supply electric power through the first inverter and the second inverter;

determining a degree of electrical load imbalance between the first inverter and the second inverter; and

controlling operating speed of the internal combustion engine as a function of the degree of the electrical load imbalance.

2. The method of claim 1, which includes changing the operating speed of the internal combustion engine in response to a change in electrical loading of the first inverter and the second inverter.

3. The method of claim 1, wherein a first DC bus is coupled between the first generator and the first inverter and a second DC bus is coupled between the second generator and the second inverter.

4. The method of claim 3, which includes:

providing electric power to at least one of the first inverter and the second inverter from an electrical energy storage device coupled to at least one of the first DC bus and the second DC bus; and

charging the electrical energy storage device with at least one of the first generator and the second generator.

5. The method of claim 4, wherein the first inverter and first DC bus are provided in a first assembly that includes a first controller, the second inverter and the second DC bus are provided in a second assembly that includes a second controller, and the controlling of the operating speed includes controlling response of the engine to electrical load transients with the first controller and second controller in a master/slave relationship.

6. The method of claim 1, which includes carrying the vehicular electric power generation system in one of a watercraft, a motor coach, a trailer, a truck, a bus, and a camper.

7. The method of claim 1, which include propelling a vehicle carrying the vehicular electric power generation system with another engine.

8. A method, comprising:

operating a vehicular electric power generation system including a variable speed internal combustion engine, a first variable speed electric power generator, a second variable speed electric power generator, a first inverter coupled to the first generator, and a second inverter coupled to the second generator;

driving the first generator and the second generator with the internal combustion engine operating at a first speed to supply electricity through the first inverter and the second inverter;

determining a change in electrical loading of the first inverter and the second inverter; and

in response to the change in electrical loading, adjusting the internal combustion engine to operate at a second speed different than the first speed.

9. The method of claim 8, which includes accounting for a degree of electrical load imbalance between the first inverter and the second inverter.

10. The method of claim 8, wherein a first DC bus is coupled between the first generator and the first inverter and a second DC bus is coupled between the second generator and the second inverter.

11. The method of claim 10, which includes:

providing electric power to at least one of the first inverter and the second inverter from an electrical energy storage device coupled to at least one of the first DC bus and the second DC bus; and

charging the electrical energy storage device with at least one of the first generator and the second generator.

12. The method of claim 11, wherein the first inverter and first DC bus are provided in a first assembly that includes a first controller, the second inverter and the second DC bus are provided in a second assembly that includes a second controller, and the determining of the change in electrical loading includes controlling response of the engine to electrical load transients with the first controller and second controller in a master/slave relationship.

13. The method of claim 8, which includes carrying the vehicular electric power generation system in one of a watercraft, a motor coach, a trailer, a truck, a bus, and a camper.

14. The method of claim 8, which include propelling a vehicle carrying the vehicular electric power generation system with another engine.

15. An apparatus, comprising a vehicular electrical power generation system, including:

a variable speed internal combustion engine;

a first variable speed electric power generator driven by the engine;

a second variable speed electric power generator driven by the engine;

a first inverter to receive electric power from the first generator and provide a first controlled electric output;

a second inverter to receive electric power from the second generator and provide a second controlled electric output;

a controller coupled to the engine, the controller being responsive to variation in electrical loading of the first inverter and the second inverter and a degree of electrical load imbalance between the first inverter and the second inverter to provide an engine control signal; and

the engine being responsive to the control signal to change rotational operating speed to adjust for the variation in electrical loading and the degree of electrical load imbalance.

16. The apparatus of claim 15, further comprising a vehicle installed with the vehicular electric power generation system and another engine to propel the vehicle.

17. The apparatus of claim 15, wherein the engine includes a shaft, the first generator includes a first rotor fixed to the shaft, and the second generator includes a second rotor fixed to the shaft.

18. The apparatus of claim 15, further comprising a first DC bus connected between the first generator and the first inverter, a second DC bus connected between the second generator and the second inverters, and an electrical energy storage device coupled to at least one of the first DC bus and the second DC bus.

19. The apparatus of claim 18, wherein the first inverter and the first DC bus are included in a first assembly, the second inverter and the second DC bus are included in a second assembly, and the controller is included in at least one of the first assembly and the second assembly.

20. The apparatus of claim 18, further including means for controlling engine response to power transients in a master/slave relationship relative to the first assembly and the second assembly.

21. The apparatus of claim 18, further including means for boosting power output with the electrical energy storage device and means for charging the electrical energy storage device.