Management of an electric power generation and storage system

• US 20080157593A1
• Filed: 06/01/2007
• Published: 07/03/2008
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Cummins Power Generation IP, Inc.
• Original Assignee: Cummins Power Generation IP, Inc.
• Inventors: Bax, Randall, Peterson, Mitchell E.
• Granted Patent: US 7,880,331 B2
• Time in Patent Office: Days
• US Class Current: 307/10.1
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02P 2201/09 Boost converter, i.e. DC-DC step up converter increasing the voltage between the supply and the inverter driving the motor general aspects of plural converters in cascade H02M
• 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

Abstract

In one technique of the present invention, DC electric power from a DC bus is inverted to provide AC electricity to one or more electrical loads, and AC power from a variable speed generator is rectified to provide a first variable amount of electric power to the DC bus. This technique also includes determining power applied to the electrical loads, and dynamically controlling the amount of power supplied from the generator and an electrical energy storage device in response to the power applied to the loads.

Claims

1. A method, comprising:

inverting DC electric power from a DC bus to provide AC electricity to one or more electrical loads;

rectifying AC power output from a variable speed generator to provide a variable amount of electric power to the DC bus;

measuring AC electric power provided to the one or more electrical loads;

determining a power control reference that changes with variation of a difference between the AC electric power and capacity of the generator to provide power to the DC bus; and

adjusting DC electric power output from an electrical energy storage device to the DC bus in response to change in the power control reference.

2. The method of claim 1, which includes carrying a system including the generator, the DC bus, the storage device, and the one or more electrical loads with a vehicle.

3. The method of claim 1, which includes:

disabling the DC electric power output from the storage device; and

charging the storage device with electricity from the generator after the disabling of the DC electric power output.

4. The method of claim 1, which includes:

decreasing the DC electric power output of the storage device during the adjusting of the DC electric power output;

increasing rotational speed of the generator during the adjusting of the DC electric power output from the storage device; and

during the increasing of the rotational speed, limiting the rate of change of the rotational speed to no more than a predefined level that is less than an available maximum rate of change.

5. The method of claim 4, which includes:

detecting a power transient; and

accelerating the rotational speed of the generator at a higher level than the predefined level in response to the power transient.

6. The method of claim 1, which includes allowing voltage on the DC bus to vary between a minimum nonzero voltage and a maximum nonzero voltage while simultaneously providing the AC electric power output from the generator and the DC electric power output from the storage device to power the one or more loads, a difference between the minimum nonzero voltage being 75% or less of the maximum nonzero voltage.

7. The method of claim 1, which includes controlling rotational speed of the generator as a function of the adjusting DC electric power output.

8. A method, comprising:

inverting DC electric power from a DC bus to provide AC electricity to one or more electrical loads;

rectifying AC power from a variable speed generator to provide a first variable amount of electric power to the DC bus;

detecting voltage and current applied to the one or more electrical loads;

determining a power control reference as a function of the voltage and the current; and

in response to the power control reference, regulating DC power from an electrical energy storage device to provide a second variable amount of electric power to the DC bus.

9. The method of claim 8, which includes carrying a system including the generator, the DC bus, the storage device, and the one or more electrical loads with a vehicle, the one or more electrical loads including an air conditioner for a living space inside the vehicle.

10. The method of claim 8, which includes:

decreasing the DC power from the storage device during the regulating;

increasing rotational speed of the generator during the decreasing of the DC power; and

during the increasing of the rotational speed, limiting the rate of change of the rotational speed to no more than 50 rpm per second.

11. The method of claim 10, which includes:

detecting a power transient; and

accelerating the rotational speed of the generator at a higher level than the predefined level in response to the power transient.

12. The method of claim 8, which includes permitting voltage on the DC bus to vary between a minimum nonzero voltage and a maximum nonzero voltage while simultaneously providing the AC power from the generator and the DC power from the storage device to power the one or more loads, a difference between the minimum nonzero voltage being 75% or less of the maximum nonzero voltage.

13. A system, comprising:

an inverter to provide AC electrical power to one or more electrical loads;

a variable voltage DC bus electrically coupled to the inverter to provide DC electric power to the inverter;

a controllable converter electrically coupled to the variable voltage DC bus and an electrical energy storage apparatus electrically coupled to the controllable converter to provide a first portion of the DC electric power to the variable voltage DC bus;

a variable speed generator to supply a variable AC power output;

a rectifier electrically coupled between the variable speed generator and the variable voltage DC bus to provide a second portion of the DC electric power rectified from the AC power output;

a sensing arrangement to detect voltage and current provided to the one or more electrical loads from the variable voltage DC bus; and

control circuitry coupled to the controllable converter and the sensing arrangement, the control circuitry being responsive to the voltage and the current to generate a power control signal indicative of a change in the AC electrical power provided to the one or more electrical loads, the controllable converter being responsive to the power control signal to change the second portion of the DC electric power provided to the variable voltage DC bus from the controllable converter circuitry.

14. The system of claim 13, further comprising a vehicle carrying the inverter, DC bus, converter, generator, rectifier, sensing arrangement, and control circuitry.

15. The system of claim 13, further comprising means for adjusting rotational speed of the generator.

16. The system of claim 15, wherein the adjusting means includes means for limiting rate of change of the rotational speed of the generator.

17. The system of claim 13, wherein the energy storage apparatus includes at least one electrochemical battery.

18. The system of claim 13, wherein the control circuitry includes a processor with means for dynamically controlling power sharing between the generator and the storage apparatus.

19. The system of claim 13, wherein the converter is structures to selectively charge the storage apparatus with electric power from the generator in response to one or more processing signals from the control circuitry.

20. An apparatus, comprising:

a variable speed generator;

an electrical energy storage device;

a DC bus coupled to the variable speed generator and the electrical energy storage device;

means for inverting DC electric power from the DC bus to provide AC electricity to one or more electrical loads;

means for rectifying AC power output from the variable speed generator to provide a variable amount of electric power to the DC bus;

means for measuring AC electric power provided to the one or more electrical loads;

means for determining a power control reference that changes with difference between the AC electric power and capacity of the generator to provide power to the DC bus; and

means for adjusting DC electric power output from the electrical energy storage device to the DC bus in response to change in the power control reference.