SYSTEM AND METHODS FOR STARTING A PRIME MOVER OF A POWER SYSTEM

• US 20120169114A1
• Filed: 12/29/2010
• Published: 07/05/2012
• Est. Priority Date: 12/29/2010
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: ANDRIS, Eric M.
• Granted Patent: US 8,853,883 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 1/00 Supplying electric power to auxiliary equipment of vehicles circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: B60L 2200/40 Working vehicles
• CPC Class Codes: B60L 50/15 with additional electric power supply with capacitors charged by engine-driven generators B60L50/40; with batteries charged by engine-driven generators B60L50/61
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 30/192 Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: B60Y 2400/114 Super-capacities
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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

A power system includes a prime mover drivingly connected to an electric motor/generator. The power system may also include a first electrical energy storage device and a second electrical energy storage device. The power system may further include power-system controls configured to selectively start the prime mover by selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device and transmitting electricity from the first electrical energy storage device to the electric motor/generator to operate the electric motor/generator as an electric motor to start the prime mover.

Claims

1. A power system, comprising:

a prime mover drivingly connected to an electric motor/generator;

a first electrical energy storage device;

a second electrical energy storage device; and

power-system controls configured to selectively start the prime mover by

selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device; and

transmitting electricity from the first electrical energy storage device to the electric motor/generator to operate the electric motor/generator as an electric motor to start the prime mover.

2. The power system of claim 1, wherein:

the power system is part of a machine having a chassis,

the second electrical energy storage device is grounded to the chassis; and

the first electrical energy storage device is electrically isolated from the chassis.

3. The power system of claim 1, wherein:

the power-system controls include a power regulator connected between the first electrical energy storage device and the second electrical energy storage device; and

charging the first electrical energy storage device with electricity from the second electrical energy storage device includes

transmitting electricity from the second electrical energy storage device to the power regulator, and

transmitting electricity from the power regulator to the first electrical energy storage device.

4. The power system of claim 1, wherein:

the power-system controls include a power regulator connected between the first electrical energy storage device and the second electrical energy storage device; and

charging the first electrical energy storage device with electricity from the second electrical energy storage device includes

transmitting electricity from the second electrical energy storage device to the power regulator at a first voltage, and

transmitting electricity from the power regulator to the first electrical energy storage device at a second voltage.

5. The power system of claim 4, wherein the second voltage is higher than the first voltage.

6. The power system of claim 1, wherein the power-system controls are further operable to transmit electricity to one or more electric power loads of the power system, including

after starting the prime mover, selectively transmitting power from the electric motor/generator and the first electrical energy storage device to a first electric power load at a first voltage;

and

selectively transmitting power from the second electrical energy storage device to a second electric power load at a second voltage.

7. The power system of claim 6, wherein the first voltage is higher than the second voltage.

8. The power system of claim 1, wherein:

the power-system controls include a position sensor for determining a rotational position of a shaft of the electric motor/generator; and

the power-system controls are further configured to determine the rotational position of the shaft of the motor/generator prior to starting the prime mover by transmitting a pulse of electricity to the electric motor/generator to rotate the shaft of the electric motor/generator while monitoring the signal from the position sensor.

9. The power system of claim 8, wherein operating the electric motor/generator to start the prime mover includes controlling the transmission of electricity to the electric motor/generator based on the determined rotational position of the shaft.

10. A method of operating a power system, the power system including a prime mover drivingly connected to an electric motor/generator, a first electrical energy storage device, and a second electrical energy storage device, the method comprising:

starting the prime mover by

selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device, and

transmitting electricity from the first electrical energy storage device to the electric motor/generator to operate the electric motor/generator as an electric motor to start the prime mover.

11. The method of claim 10, further comprising:

selectively supplying electricity from the first electrical energy storage device to a first electric power load at a first voltage; and

selectively supplying electricity from the second electrical energy storage device to a second electric power load at a second voltage.

12. The method of claim 11, wherein the first voltage is higher than the second voltage.

13. The method of claim 11, further comprising, after starting the prime mover, operating the electric motor/generator as a generator and supplying electricity from the electric motor/generator to the first electric power load.

14. The method of claim 10, further comprising:

before starting the prime mover, determining whether the first electrical energy storage device has enough energy to start the prime mover; and

wherein selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device before starting the prime mover includes charging the first electrical energy storage device with electricity from the second electrical energy storage device if the second electrical energy storage device has insufficient energy to start the prime mover.

15. The method of claim 10, wherein charging the first electrical energy storage device with electricity from the second electrical energy storage device includes supplying electricity from the first electrical energy storage device at a first voltage and supplying electricity to the second electrical energy storage device at a second voltage, higher than the first voltage.

16. A machine, comprising:

a chassis

a power system, the power system including

a prime mover drivingly connected to an electric motor/generator;

an electric power load;

a power line operable to transmit electricity from the electric motor/generator to the electric power load;

a first electrical energy storage device grounded to the chassis;

a second electrical energy storage device, the second electrical energy storage device being electrically isolated from the chassis; and

power-system controls configured to start the prime mover by using energy supplied by the second electrical energy storage device to operate the electric motor/generator as an electric motor to start the prime mover.

17. The machine of claim 16, wherein starting the prime mover by using energy supplied by the second electrical energy storage device to operate the electric motor/generator as an electric motor includes transmitting electricity from the second electrical energy storage device to the electric motor/generator without transmitting the electricity to the first electrical energy storage device.

18. The machine of claim 17, wherein transmitting electricity from the second electrical energy storage device to the electric motor/generator without transmitting the electricity to the first electrical energy storage device includes

transmitting electricity from the first electrical energy storage device to a power regulator at a first voltage;

and

transmitting electricity to the electric motor/generator at a second voltage, higher than the first voltage.

19. The machine of claim 16, wherein the power-system controls are further operable to transmit electricity to one or electric power loads of the power system, including

after starting the prime mover, selectively transmitting power from the electric motor/generator and the first electrical energy storage device to a first electric power load at a first voltage;

and

selectively transmitting power from the second electrical energy storage device to a second electric power load at a second voltage.

20. The machine of claim 16, wherein starting the prime mover by using energy supplied by the second electrical energy storage device to operate the electric motor/generator as an electric motor includes

selectively charging the first electrical energy storage device with electricity from the second electrical energy storage device;

and

transmitting electricity from the first electrical energy storage device to the electric motor/generator to operate the electric motor/generator as an electric motor to start the prime mover.