Shore power transfer switch

• US 20080164850A1
• Filed: 12/28/2007
• Published: 07/10/2008
• Est. Priority Date: 12/29/2006
• Status: Active Grant

• Current Assignee: Cummins Power Generation IP, Inc.
• Original Assignee: Cummins Power Generation IP, Inc.
• Inventors: Peterson, Mitchell E., Marlenee, Alyssa, Ayana, Elias
• Granted Patent: US 8,085,002 B2
• Time in Patent Office: Days
• US Class Current: 322/1
• CPC Class Codes: B60H 1/00364 for caravans or trailers
• CPC Class Codes: H02J 2310/40 The network being an on-board power network, i.e. within a vehicle
• CPC Class Codes: H02J 3/007 Arrangements for selectively connecting the load or loads to one or several among a plurality of power lines or power sources for providing uninterruptable power supply H02J9/00
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 9/00 Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting

Abstract

A vehicle includes a mobile electric power generation system including a mobile power source such as a generator. An external power interface is included to connect to an external electrical power source. An AC electric power distribution bus is included to power electric loads of the vehicle and a power switch device is provided to selectively provide AC electric power on the power distribution bus from one of the respective power sources with a default to select one of the sources whenever it is present.

Claims

1. An apparatus, comprising:

a mobile electric power generation system including a mobile power source with a variable speed generator, an external power interface to connect to an external electrical power source when the electric power generation system is stationary, an AC electric power distribution bus, and a power switch device to selectively provide AC electric power on the power distribution bus from one of the power source and the external power interface, the power switch including;

a first normally open contactor between the external power interface and the power distribution bus, a normally closed switch, a first normally closed contactor, and a first contactor state control;

a second normally open contactor between the mobile power source and the power distribution bus, a normally open switch, a second normally closed contactor, and a second contactor state control; and

control circuitry to selectively switch each of an external power circuit and a mobile power circuit between an opened state and a closed state, the external power circuit connecting the normally closed switch, the first contactor control and the second normally closed contactor in series, the generated power circuit connecting the normally open switch, the second contactor state control and the first normally closed contactor in series.

2. The apparatus of claim 1, further comprising a vehicle carrying the mobile electric power generation system.

3. The apparatus of claim 2, where the vehicle is a motor coach with one or more air conditioners and the one or more air conditioners provide an electrical load on the power distribution bus.

4. The apparatus of claim 1, wherein the mobile power source includes an inverter electrically connected to the generator by a DC bus and an electrical energy storage device coupled to the DC bus, and the inverter is electrically connected between the DC bus and the second normally open contactor.

5. The apparatus of claim 1, wherein the control circuitry includes a means for detecting poor power quality from the external power interface and the normally closed switch is responsive to the detecting means to change the normally closed switch to an open state to break the external power circuit.

6. The apparatus of claim 5, wherein the normally open switch is responsive to the control circuitry to change to close when the external power control circuit is in the opened state and electricity from the mobile power source is available.

7. The apparatus of claim 1, wherein the first contactor state control includes a first electromagnetic coil responsive to the external power circuit, the second contactor state control includes a second electromagnetic coil responsive to the mobile power circuit, the normally closed switch is a first relay mechanism responsive to the control circuitry and the normally open switch is a second relay mechanism responsive to the control circuitry.

8. An apparatus, comprising:

a power switch device to selectively provide AC electric power on the power distribution bus from one of a local power source and an external power interface, including;

a first normally open contactor between the external power interface and the power distribution bus, a first switch, and a first contactor state control;

a second normally open contactor between the inverter and the power distribution bus, a second switch, and a second contactor state control;

an external power control circuit through the first switch and the first contactor state control, the external power control circuit having a default closed state when external power is available at the external power interface, the default closed state of the external power circuit providing electricity from the external power interface to the first contactor state control to close the first normally open contactor and correspondingly route the AC electric power to a power distribution bus from the external power interface; and

a local power control circuit through the second switch and the second contactor state control, the local power control circuit having a default open state when the external power circuit is in the default closed state.

9. The apparatus of claim 8, further comprising a vehicle carrying the local power source the external power interface, and the power distribution bus, the external power interface being removably connectable to the external power source to provide shore power to the vehicle.

10. The apparatus of claim 8, further comprising a first normally closed contactor in the local power circuit and a second normally closed contactor in the external power circuit, the first normally closed contactor changing state in response to the first contactor state control to be open when the first normally open contactor is closed, and the second normally closed contactor changing state in response to the second contactor state control to be closed when the second normally open contactor is closed.

11. The apparatus of claim 9, wherein the first contactor state control includes a first electromagnetic coil responsive to the external power circuit, the second contactor state control includes a second electromagnetic coil responsive to the local power circuit, the first switch is a normally closed type, and the second switch is a normally open type.

12. The apparatus of claim 11, further comprising a controller, the controller including means for detecting poor power quality from the external power interface and the normally closed switch is responsive to the detecting means to change the first switch to an open state to put the external power circuit in an open state.

13. The apparatus of claim 12, wherein the second switch is responsive to the controller to close when the external power control circuit is in the open state and electricity from the local power source is available.

14. The apparatus of claim 13, wherein the first contactor state control includes a first electromagnetic coil responsive to the external power circuit, the second contactor state control includes a second electromagnetic coil responsive to the local power circuit, the first switch is a normally closed relay mechanism responsive to the controller and the second switch is a normally open relay mechanism responsive to the controller.

15. A method, comprising:

providing a mobile electric power system including an external power interface to receive electricity from a source external to the electric power supply system when the electric power supply system is stationary, a power generation subsystem including a variable speed generator connected to an inverter, and a power switch device connected to an AC electric power distribution bus, the power switch device including a first normally open contactor connected between the external power interface and the power distribution bus and a second normally open contactor connected between the inverter and the power distribution bus;

operating the electric power supply system with a default condition of at least initially providing external power to the power distribution bus in response to the external power becoming available through the external power interface by;

closing the first contactor in response to the external power becoming available through the external power interface to route the external power to the power distribution bus; and

maintaining the second contactor in an open contactor state while the first normally open contactor is closed.

16. The method of claim 15, which includes:

detecting the external power through the external power interface has one or more unacceptable characteristics;

in response to the detecting of the one or more unacceptable characteristics, opening the first contactor; and

closing the second contactor to route electricity from the power generation subsystem to the power distribution bus.

17. The method of claim 15, which includes carrying the mobile electric power supply system with a vehicle to provide electricity to one more electric loads of the vehicle.

18. The method of claim 15, which includes:

controlling the first contactor with a first contactor state control responsive to electricity through the external power interface; and

controlling the second contactor with a second contactor state control responsive to electricity generated with the mobile electric power system.

19. The method of claim 18, which includes:

providing the electricity through the external power interface to the first contactor state control through a normally closed controllable switch; and

providing the electricity generated with the mobile electric power system to the second contactor state control through a normally open controllable switch.

20. The method of claim 19, wherein the first contactor state control includes a first electromagnetic coil, the second contactor state control includes a second electromagnetic coil, the first switch is a normally closed relay mechanism and the second switch is a normally open relay mechanism.

21. A mobile electric power supply system, comprising:

a power generation subsystem including a variable speed generator connected to an inverter;

an external power interface to receive electricity from a source external to the electric power supply system when the power supply system is stationary;

a power switch device connected to an AC electric power distribution bus, the power switch device including a first normally open contactor connected between the external power interface and the power distribution bus, a second normally open contactor connected between the inverter and the power distribution bus, means for operating the electric power supply system with a default condition of at least initially providing external power to the power distribution bus in response to the external power becoming available through the external power interface, the operating means including means for closing the first normally open contactor in response to the external power becoming available through the external power interface to route the external power to the power distribution bus and means for maintaining the second normally open contactor in an open contactor state while the first normally open contactor is closed.