Uninterruptible power supply systems and methods for communication systems

1. An uninterruptible power supply adapted to be connected between an AC line and a load, comprising:

a battery system for storing battery power;

an inverter operatively connected to the battery system;

a transformer comprising

a primary winding adapted to be connected to the AC line,

a load winding adapted to be connected to the load, and

an inverter winding operatively connected to the inverter; and

a controller for controlling the inverter to operate in

a first mode in which the inverter supplies power to the battery system,

a second mode in which the inverter supplies power to the load winding using battery power stored in the battery system, and

a third mode in which the inverter supplies power to the primary winding using battery power stored in the battery system.

2. An uninterruptible power supply as recited in claim 1 , in which the controller controls the inverter to operate in one the first, second, and third modes when at least one characteristic of a primary power signal present at the primary winding is within certain predetermined conditions.

3. An uninterruptible power supply as recited in claim 2 , in which the controller controls the inverter to operate in one of the first, second, and third modes in response to a price associated with the primary power signal.

4. An uninterruptible power supply as recited in claim 2 , in which, when the controller controls the inverter to operate in the third mode, the controller controls the inverter to operate in one of the first, second, and third modes by comparing a price associated with the primary power signal and a cost associated with reduction of life of the battery system.

5. An uninterruptible power supply as recited in claim 2 , in which the controller controls the inverter to operate in one of the first, second, and third modes by measuring a voltage of the primary power signal.

6. An uninterruptible power supply as recited in claim 2 , in which the controller controls the inverter to operate in one of the first and third modes when the primary power signal is present.

7. An uninterruptible power supply as recited in claim 2 , in which the controller controls the inverter to operate in:

the first and third modes mode when at least one characteristic of the primary power signal is within a set of predetermined conditions and by comparing a price associated with the primary power signal and a cost associated with reduction of life of the battery system; and

the second mode when at least one characteristic of the primary power signal is not within the set of predetermined conditions.

8. An uninterruptible power supply as recited in claim 1 , in which the controller controls the inverter to operate in the first, second, and third modes by measuring at least one characteristic of the battery system.

9. An uninterruptible power supply as recited in claim 1 , in which the primary winding is connected to a utility power source.

10. An uninterruptible power supply as recited in claim 1 , further comprising at least one secondary source for providing secondary power, wherein:

in the first mode, power is supplied to the battery system using secondary power from the at least one secondary power source;

in the second mode, power is supplied using secondary power from the at least one secondary power source; and

in the third mode, power is supplied using secondary power from the at least one secondary power source.

11. An uninterruptible power supply as recited in claim 1 , further comprising at least one generator for providing generator power, wherein:

in the first mode, power is supplied using generator power from the at least one generator;

in the second mode, power is supplied using generator power from the at least one generator; and

in the third mode, power is supplied using generator power from the at least one generator.

12. A method of supplying uninterruptible electric power to a load comprising the steps of:

providing a battery system for storing battery power;

operatively connecting an inverter to the battery system;

providing a transformer comprising a primary winding configured to be connected to an AC line, a load winding configured to be connected to the load, and an inverter winding;

operatively connecting the inverter winding to the inverter; and

controlling the inverter to operate in

a first mode in which the inverter supplies power to the battery system from the primary winding,

a second mode in which the inverter supplies power to the load winding using battery power stored in the battery system, and

a third mode in which the inverter supplies power to the primary winding using battery power stored in the battery system.

13. A method as recited in claim 12 , in which inverter is controlled to operate in the first, second, and third modes when at least one characteristic of a primary power signal present at the primary winding is within certain predetermined conditions.

14. A method as recited in claim 12 , in which the inverter is controlled to operate in the first, second, and third modes by measuring at least one characteristic of the battery system.

15. An uninterruptible power supply adapted to be connected between an AC line and a load, comprising:

a battery system for storing battery power;

an inverter operatively connected to the battery system;

a transformer comprising

a primary winding adapted to be connected to the AC line,

a load winding adapted to be connected to the load, and

an inverter winding operatively connected to the inverter; and

a controller for controlling the inverter to operate based on at least one characteristic of a primary power signal present at the primary winding in

a first mode in which the inverter supplies power to the battery system,

a second mode in which the inverter supplies power to the load winding using battery power stored in the battery system, and

a third mode in which the inverter supplies power to the primary winding using battery power stored in the battery system.

16. An uninterruptible power supply as recited in claim 15 , in which the controller controls the inverter to operate:

in the first and third modes mode when at least one characteristic of the primary power signal is within a set of predetermined conditions and by comparing a price associated with the primary power signal and a cost associated with reduction of life of the battery system; and

in the second mode when at least one characteristic of the primary power signal is not within the set of predetermined conditions.

17. An uninterruptible power supply as recited in claim 16 , in which the controller controls the inverter to operate in the first, second, and third modes by measuring at least one characteristic of the battery system.

18. An uninterruptible power supply as recited in claim 15 , in which the primary source is a utility.

19. An uninterruptible power supply as recited in claim 18 , further comprising at least one secondary source for providing secondary power, wherein:

in the first mode, power is supplied using secondary power from the at least one secondary power source;

in the second mode, power is supplied using secondary power from the at least one secondary power source; and

in the third mode, power is supplied using secondary power from the at least one secondary power source.

20. An uninterruptible power supply as recited in claim 19 , further comprising at least one generator for providing generator power, wherein:

in the first mode, power is selectively supplied to the battery using generator power from the at least one generator;

in the second mode, power is selectively supplied using generator power from the at least one generator; and

in the third mode, power is selectively supplied using generator power from the at least one generator.