Ferroresonant transformer systems and methods

1. A ferroresonant transformer assembly adapted to be connected to a primary power source, an inverter system, a resonant capacitor, and at least one load, the ferroresonant transformer assembly comprising:

a core;

a main shunt arranged to define a primary side and a secondary side of the ferroresonant transformer assembly;

first windings arranged on the primary side of the ferroresonant transformer assembly, where the first windings are configured to be operatively connected to the primary power source;

second windings arranged on the secondary side of the ferroresonant transformer assembly, where the second windings are configured to be operatively connected to the inverter system;

third windings arranged on the secondary side of the ferroresonant transformer assembly;

a first tap connector operatively connected to a first intermediate point defined by the third windings;

a second tap connector operatively connected to a second intermediate point defined by the third windings; and

a selection connector operatively connected to the at least one load; whereby

based on voltage requirements of the at least one load, the selection connector is operatively selectively connected to a selected tap connector selected from the first and second tap connectors.

2. A ferroresonant transformer assembly as recited in claim 1 , further comprising:

a cable assembly operatively connected between the selection connector and at least one of a plurality of loads.

3. A ferroresonant transformer assembly as recited in claim 2 , in which the cable assembly is operatively connected between the selection connector and a plurality of loads.

4. A ferroresonant transformer assembly as recited in claim 1 , in, the third windings are configured to be selectively operatively connected to or disconnected from the resonant capacitor.

5. A ferroresonant transformer assembly as recited in claim 4 , in which the ferroresonant transformer

operates as a resonant circuit when the third windings are operatively connected to the resonant capacitor; and

does not operate as a resonant circuit when the third windings are disconnected from the resonant capacitor.

6. An uninterruptible power supply system adapted to be connected to a primary power source, a battery system, and at least one load, the uninterruptible power supply comprising:

a ferroresonant transformer comprising

a core;

a main shunt arranged to define a primary side and a secondary side of the ferroresonant transformer;

first windings arranged on the primary side of the ferroresonant transformer;

second windings arranged on the secondary side of the ferroresonant transformer; and

third windings arranged on the secondary side of the ferroresonant transformer; and

an inverter, where the inverter is operatively connected to the second windings;

a first tap connector operatively connected to a first intermediate point defined by the third windings;

a second tap connector operatively connected to a second intermediate point defined by the third windings; and

a selection connector operatively connected to the at least one load;

a resonant capacitor; wherein

the first windings are operatively connected to the primary power source;

the inverter is operatively connected to the battery system;

in a line mode, power flows from the primary source to the at least one load through the ferroresonant transformer; and

in a standby mode, power flows from the inverter to the at least one load through the ferroresonant transformer; and

based on voltage requirements of the at least one load, the selection connector is operatively selectively connected to a selected tap connector selected from the first and second tap connectors.

7. An uninterruptible power supply system as recited in claim 6 , further comprising a select switch, where the select switch is configured to:

connect the resonant capacitor to the third windings when the uninterruptible power supply is in the line mode; and

disconnect the resonant capacitor from the third windings when the uninterruptible power supply is in the standby mode.

8. An uninterruptible power supply system as recited in claim 6 , in which the main shunt is formed by an inductor.

9. An uninterruptible power supply system as recited in claim 6 , in which the ferroresonant transformer

operates as a resonant circuit when the third windings are operatively connected to the resonant capacitor; and

does not operate as a resonant circuit when the third windings are disconnected from the resonant capacitor.

10. An uninterruptible power supply system as recited in claim 6 , in which the inverter is pulse-width modulated.

11. An uninterruptible power supply system as recited in claim 6 , in which the inverter is a switch mode power supply.

12. An uninterruptible power supply system as recited in claim 6 , in which the primary power source is a utility power supply.

13. An uninterruptible power supply system as recited in claim 6 , further comprising a filter capacitor operatively connected across at least a portion of the third windings.

14. A method of supplying uninterruptible power to at least one load from a primary power source and a battery system, the method comprising the steps of:

providing a ferroresonant transformer comprising

a core;

a main shunt arranged to define a primary side and a secondary side of the ferroresonant transformer;

first windings arranged on the primary side of the ferroresonant transformer;

second windings arranged on the secondary side of the ferroresonant transformer;

third windings arranged on the secondary side of the ferroresonant transformer, where the third windings define first and second intermediate points; operatively connecting a first tap connector to the first intermediate point defined by the third windings;

operatively connecting a second tap connector to the second intermediate point defined by the third windings;

operatively connecting a selection connector to the at least one load;

operatively connecting an inverter to the second windings;

operatively connecting the first windings to the primary power source;

operatively connecting the inverter to the battery system;

in a line mode, causing power to flow from the primary source to the at least one load through the ferroresonant transformer;

in a standby mode, causing power to flow from the inverter to the at least one load through the ferroresonant transformer; and

based on voltage requirements of the at least one load, operatively selectively connecting the selection connector to a selected tap connector selected from the first and second tap connectors.

15. A method as recited in claim 14 , further comprising the steps of:

providing a select switch;

operating the select switch to connect a resonant capacitor to the third windings when the uninterruptible power supply is in the line mode; and

operating the select switch to disconnect the resonant capacitor from the third windings when the uninterruptible power supply is in the standby mode.

16. A method as recited in claim 14 , in which the step of providing the ferroresonant transformer comprises the step of arranging an inductor to form the main shunt.

17. A method as recited in claim 14 , in which the step of providing the inverter comprises the step of providing a pulse-width modulated inverter.

18. A method as recited in claim 14 , in which the step of providing the inverter comprises the step of providing a switch mode power supply.

19. A method as recited in claim 14 , in which the step of operatively connecting the first windings to the primary power source comprises the step of operatively connecting the first windings to a utility power supply.

20. A method as recited in claim 14 , further comprising the step of operatively connecting a filter capacitor across at least a portion of the third windings.