received by the International Bureau on 05 June 2015(05.06.2015)

CLAIMS

What is claimed is:

1. A hybrid alternating current (AC)/direct current (DC) distribution system for multiple-floor buildings, the system comprising:

a plurality of per-floor rectifiers for converting, at each floor in a multiple floor building, supply side AC to DC, each rectifier being configured to supply a plurality of DC loads associated with one floor of the multiple-floor building;

a plurality of per-floor DC busses, each of the DC busses being configured to distribute the DC to the DC loads its respective floor; and

at least one AC bus configured to supply AC to AC loads on the building.

2. The hybrid AC/DC distribution system of claim 1 comprising at least one DC UPS coupled to the per-floor DC busses for maintaining a predetermined DC voltage on each of the per-floor DC busses in the event of an AC power interruption.

3. The hybrid AC/DC distribution system of claim 1 comprising a centralized inverter configured to convert DC to AC for the building and to supply AC loads within the building via the at least one AC bus.

4. The hybrid AC/DC distribution system of claim 1 comprising a plurality of per-floor inverters, each per-floor inverter configured to convert the DC to AC on its respective floor and to supply plural AC loads on its respective floor via the at least one AC bus.

5. The hybrid AC/DC distribution system of claim 1 wherein the at least one AC bus is configured to connect to an external AC supply.

6. The hybrid AC/DC distribution system of claim 2 wherein the at least one DC UPS comprises a central DC UPS for maintaining the predetermined DC voltage on the plurality of floors in the building in the event of an AC power interruption.

7. The hybrid AC/DC distribution system of claim 2 wherein the at least one DC UPS comprises a plurality of per-floor DC UPSs, each per

is floor DC UPS configured to maintain the predetermined DC voltage on its respective floor in the event of an AC power interruption.

8. The hybrid AC/DC distribution system of claim 7 wherein each per- floor DC UPS includes a battery having a controlled connection to the DC bus supplying the DC loads on its respective floor.

9. The hybrid AC/DC distribution system of claim 8 wherein the controlled connection includes a pair of silicon controlled rectifier (SCR) devices connected in parallel with each other, a switch connected in series with the SCR devices between the battery and the DC bus, and a controller for controlling operation of the SCR devices and the switch to control the connection of the battery to the DC bus and to control charging of the battery.

10. The hybrid AC/DC distribution system of claim 8 wherein the controller controls the SCR devices and the switch to pre-charge the battery before connecting the UPS to the DC bus to a minimum battery voltage level that the DC loads can accept and to limit maximum charging current.

1 1. The hybrid AC/DC distribution system of claim 8 wherein the controller controls the SCR devices and the switch to allow charging of the battery from the per-floor rectifier when an indication of DC load is below a threshold.

12. The hybrid AC/DC distribution system of claim 8 wherein the controller is configured to control the SCR devices and the switch to connect the battery to the DC bus to supply DC from the battery to the DC bus in the event of an AC power interruption.

13. The hybrid AC/DC distribution system of claim 8 wherein the controller is configured to control the SCR devices and the switch to operate in a recovery mode after AC power is restored from an interruption to control the per-floor rectifier to supply the DC loads and to charge the battery to a minimum DC voltage.

14. The hybrid AC/DC distribution system of claim 8 wherein the controller is configured to control the SCR devices and the switch to operate in a battery idle mode during normal load conditions where

19 the SCR devices are non-conductive and the battery is thereby isolated from the DC bus.

15. The hybrid AC/DC distribution system of claim 8 wherein the controller is configured to control the SRC devices and the switch to connect the battery to the DC bus during heavy load conditions to reduce DC voltage ripple on the DC bus.

16. A hybrid alternating current (AC)/direct current (DC) distribution method for multiple-floor buildings, the method comprising:

rectifying supply side AC to DC using a plurality of per-floor rectifiers configured to convert, at each floor in a multiple floor building, the supply side AC to DC on its respective floor of the multiple floor building and to supply a plurality of DC loads on its respective floor;

distributing, using a plurality of per-floor DC buses, the DC to the DC loads; and

supplying AC power to AC loads in the building.

17. The hybrid AC/DC distribution method of claim 16 comprising maintaining a predetermined DC voltage level on the per-floor DC busses in the event of an AC power interruption.

18. The hybrid AC/DC distribution method of claim 16 wherein supplying AC power to the AC loads includes converting the DC to AC utilizing a centralized inverter that converts DC to AC and wherein the AC bus supplies AC to a plurality of floors in the building.

19. The hybrid AC/DC distribution method of claim 16 wherein supplying AC power to the AC loads includes converting the DC to AC utilizing a plurality of per-floor inverters, each per-floor inverter rectifying the DC to AC on its respective floor and supplying plural AC loads on its respective floor.

20. The hybrid AC/DC distribution system of claim 16 wherein supplying AC power to the AC loads includes connecting the AC loads to an external AC power supply.

21 . The hybrid AC/DC distribution method of claim 17 wherein maintaining the predetermined DC voltage level on the per-floor DC

20 busses comprises providing a central UPS for maintaining the predetermined DC voltage on the per-floor DC busses.

22. The hybrid AC/DC distribution method of claim 17 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises providing a plurality of per-floor UPSs, each per- floor UPS being configured to maintain the predetermined DC voltage on its respective floor in the event of an AC power interruption.

23. The hybrid AC/DC distribution method of claim 22 wherein each per- floor UPS includes a battery having a controlled connection to the DC bus on its respective floor during charging and discharging.

24. The hybrid AC/DC distribution method of claim 23 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises providing a pair of silicon controlled rectifier (SCR) devices connected in parallel with each other, a switch connected in series with the SCR devices between the battery and each per-floor DC bus, and a controller for controlling operation of the SCR devices and the switch to control the connection of the battery to the DC bus and to control charging of the battery.

25. The hybrid AC/DC distribution method of claim 24 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises controlling the SCR devices and the switch to pre- charge the battery before connecting the UPS to the DC bus to a minimum battery voltage level that the DC loads can accept and to limit maximum charging current.

26. The hybrid AC/DC distribution method of claim 24 wherein maintaining a predetermined DC voltage level on the per-floor DC busses comprises controlling the SCR devices and the switch to allow charging of the battery from the at least one rectifier when an indication of DC load is below a threshold.

27. The hybrid AC/DC distribution method of claim 24 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises controlling the SCR devices and the switch to

21 connect the battery to the DC bus to supply DC from the battery to the DC bus in the event of an AC power interruption.

28. The hybrid AC/DC distribution method of claim 24 wherein maintaining the predetermined DC voltage level on the per-floor DC buses comprises controlling the SCR devices and the switch to operate in a recovery mode after AC power is restored from an interruption to control the at least one rectifier to operate in its maximum power capability to supply the DC loads and to charge the battery to a minimum DC voltage.

29. The hybrid AC/DC distribution method of claim 24 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises controlling the SCR devices and the switch to operate in a battery idle mode during normal load conditions where the SCR devices are non-conductive and the battery is thereby isolated from the DC bus.

30. The hybrid AC/DC distribution method of claim 24 wherein maintaining the predetermined DC voltage level on the per-floor DC busses comprises controlling the SRC devices and the switch to connect the battery to the DC bus during heavy load conditions to reduce DC voltage ripple on the DC bus.

31. The hybrid AC/DC distribution method of claim 16 embodied as a plurality of machine-readable instructions stored on a non-transitory computer readable storage medium and configured to be executed by at least one computer processor to perform the method.

32. A direct current (DC) uninterruptable power supply (UPS), comprising:

a battery connector for connecting to a battery;

a controller configured to control connection of the battery to a DC bus that supplies at least one DC load, disconnection of the battery from the DC bus, and charging of the battery; and

at least one switch located between the battery connector and the DC bus, the at least one switch being controllable by the controller to connect the battery to the DC bus in response to interruption of

22 power to the DC bus and to disconnect the battery from the DC bus in response to restoration of power to the DC bus.

33. The DC UPS of claim 32 wherein the DC bus comprises a bus emanating from a central rectifier that supplies DC power to an entire building.

34. The DC UPS of claim 32 wherein the DC bus comprises a bus emanating from a per-floor rectifier of a plurality of per-floor rectifiers, each of which supplies DC power to a single floor within a building.

35. The DC UPS of claim 32 wherein the at least one switch comprises a pair of silicon controller rectifier (SCR) devices connected in parallel with each other and a switch connected in series with the SCR devices between the battery connection and the DC bus.

36. The hybrid AC/DC distribution system of claim 1 wherein the per-floor rectifiers include one rectifier for each floor in the multiple floor building.

37. The hybrid AC/DC distribution method of claim 16 wherein the per- floor rectifiers include one rectifier for each floor in the multiple floor building.

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