(en)A direct current power system according to one non-limiting embodiment includes a direct current power source operable to distribute a direct current voltage throughout at least one structure, and at least one controller operable to selectively couple a direct current load to the direct current voltage in response to a wireless signal from an energy-harvesting switch.

1.ApplicationNumber: US-41780009-A
1.PublishNumber: US-2009251072-A1
2.Date Publish: 20091008
3.Inventor: BARNETT THOMAS ALAN
LOTT JEFFREY
XU JIAN

4.Inventor Harmonized: BARNETT THOMAS ALAN(US)
LOTT JEFFREY(US)
XU JIAN(CA)

5.Country: US
6.Claims:
(en)A direct current power system according to one non-limiting embodiment includes a direct current power source operable to distribute a direct current voltage throughout at least one structure, and at least one controller operable to selectively couple a direct current load to the direct current voltage in response to a wireless signal from an energy-harvesting switch.

7.Description:
(en)BACKGROUND OF THE INVENTION
The application claims priority to U.S. Provisional Application No. 61/042,449 which was filed on Apr. 4, 2008.
This application relates to power distribution systems, and more particularly to a direct current (“DC”) distribution system.
Electrical systems for buildings, such as residential buildings, are designed for alternating current (“AC”) and AC loads. Some loads, however, such as light-emitting diodes (“LEDs”), may require DC to operate. Existing LED lighting solutions have incorporated a substantial amount of electronics in a LED lamp to convert AC to DC to power the LED lamp. Other DC loads require AC adapters plugged into electrical outlets that perform an AC to DC conversion.
SUMMARY OF THE INVENTION
A DC power system according to one non-limiting embodiment includes a DC power source operable to distribute a DC voltage throughout at least one environment, and at least one controller operable to selectively couple a DC load to the DC voltage in response to a wireless signal from an energy-harvesting switch.
A DC lighting system according to one non-limiting embodiment includes a DC power source operable to distribute a DC voltage throughout at least one environment, and at least one controller operable to selectively couple a DC lighting source to the DC voltage in response to a control signal.
A method for controlling electrical power in an environment includes converting an AC voltage to a first DC voltage, distributing the DC voltage in an environment, converting the first DC voltage to a second DC voltage, and selectively coupling a DC load to the second DC voltage in response to a control signal.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates a first low voltage DC distribution system.
FIG. 2 schematically illustrates a second DC distribution system.
FIG. 3 schematically illustrates a third DC distribution system.
FIG. 4 schematically illustrates a fourth DC distribution system.
FIG. 5 schematically illustrates a fifth DC distribution system.
FIG. 6 a schematically illustrates a first wireless switching application.
FIG. 6 b schematically illustrates a second wireless switching application.
FIG. 7 schematically illustrates the use of the system of FIG. 1 across a building.



DETAILED DESCRIPTION OF THE EMBODIMENTS
FIGS. 1-5 schematically illustrate a plurality of DC distribution systems 10 a - e . FIG. 1 schematically illustrates a first DC distribution system 10 a that includes an AC power source 12 and a power converter 14 coupled to the AC power source 12 . The power converter 14 is operable to convert an AC input voltage from the AC power source 12 to a DC voltage.
Throughout this application an example AC input voltage of 120 VAC is illustrated. However, it is understood that other AC input voltages could be used. For example, 220 VAC is commonly used in Europe, and could be used with any of the disclosed systems 10 a - e. The power converter 14 supplies power throughout at least one structure (see, e.g. FIG. 7 ) via a plurality of power lines 26 to a plurality of controllers 16 a - c.
Each controller 16 is coupled to at least one DC load 18 via power lines 28 . In one example the DC loads 18 include lighting loads (e.g. luminaires having LEDs). Of course, other DC lighting loads, and other DC non-lighting loads could be used. Also, although FIG. 1 illustrates a single load 18 coupled to each controller 16 , it is understood that the controller 16 could be a multi-channel controller, and that other quantities of loads 18 could be coupled to each controller 16 (see, e.g., FIGS. 6 a - b ). In one example each of the controllers 16 a - c are operable to receive wireless signal commands from an energy-harvesting switch 32 (see FIGS. 6 a - b ).
FIG. 2 schematically illustrates a second DC distribution system 10 b . Instead of a single power converter 14 as in the system 10 a of FIG. 1 , the system 10 b includes a plurality of power converters 20 a - c. In the context of a structure (e.g. a building), AC voltage may be distributed along power lines 25 . The plurality of power converters 20 a - c are operable to convert the AC voltage to a DC voltage, and to distribute the DC voltage along power lines 26 to the controllers 16 . The controllers 16 a - c are operable to distribute the DC voltage via power lines 28 to loads 18 a - c.
FIG. 3 schematically illustrates a third DC distribution system 10 c that includes a first power converter 22 and a plurality of second power converters 24 a - c coupled to the first power converter 22 . The first power converter 22 is operable to convert an AC input voltage from the AC power source 12 into a first DC voltage, which is distributed along power lines 25 . Although FIG. 3 illustrates the first DC voltage as being 40 VDC, it is understood that other DC voltages could be used. The plurality of second power converters 24 a - c are operable to convert the first DC voltage to a second DC voltage that is higher or lower than the first DC voltage. The second DC voltage is distributed along power lines 26 to controllers 16 a - c. The controllers 16 a - c are operable to distribute the second DC voltage along power lines 28 to loads 18 a - c.
FIG. 4 schematically illustrates a fourth DC distribution system 10 d that includes a DC power source 40 , operable to distribute a first DC voltage along power lines 25 . The DC power source 40 may include, for example, a solar power source, a battery stack or plurality of battery stacks, or an electric generator. A plurality of step down DC converters 42 a - c are operable to convert the first DC voltage from the DC power source 40 to a second DC voltage that is lower than the first DC voltage, for distribution along power lines 26 . The controllers 16 a - c are operable to distribute the second DC voltage along power lines 28 to loads 18 a - c. Of course, the step down DC converters 42 a - c could also be step up DC converters and the second DC voltage could be higher than the first DC voltage.
FIG. 5 schematically illustrates a fifth DC distribution system 10 e that includes a first power converter 23 and a plurality of second power converters 41 a - c coupled to the first power converter 23 . The first power converter 23 is operable to convert a first AC input voltage from the AC power source 12 into a second AC voltage that is higher or lower than the first AC voltage. The second AC voltage is distributed along power lines 25 . The plurality of second power converters 41 a - c are operable to convert the second AC voltage to a DC voltage. The DC voltage is distributed along power lines 26 to controllers 16 a - c, which are operable to distribute the DC voltage along power lines 28 to loads 18 a - c.
FIG. 6 a schematically illustrates a first example wireless switching application 30 a . An energy-harvesting switch 32 a is operable to transmit wireless signals to a receiver 34 , which associated with the controller 16 . However, it is understood that the receiver would not need to be included within the controller 16 , and could be external to the controller 16 . Also, it is understood that the controller 16 could act as a housing for a power converter (e.g. power converter 20 , 24 , etc.).
The controller 16 selectively couples a load 36 a - c to a power source 38 in response to wireless signals sent from the switch 32 a to the receiver 34 . The load 36 a is a lighting load coupled to a first channel of the controller 16 , the load 36 b is a lighting load coupled to a second channel of the controller 16 , and the load 36 c is coupled to a third channel of the controller 16 . As in the other examples, it is possible that the controller 16 may be coupled to more or less than three items. One energy-harvesting switch is available from Verve Living Systems Product No. X3100, and one controller is available from Verve Living Systems Product No. X2110. However, it is understood that this specific switch and controller would not need to be used. For example, the energy-harvesting switch 32 a could correspond to a motion sensor may operable to turn lighting loads 36 a - b ON or OFF.
FIG. 6 b schematically illustrates a second example wireless switching application 30 b , in which a plurality of loads 43 a - d are connected in parallel to a first channel of controller 16 ′, a plurality of loads 44 a - b are connected in parallel to a second channel of controller 16 ′, and a plurality of loads 46 a - c are connected in parallel to a third channel of controller 16 ′. In this example, the loads 43 a - d , 44 a - b , and 46 a - c are addressable so-called “smart loads” capable of two-way communication with the receiver 34 ′. Such addressable functionality enables multiple loads such as the loads 43 a - d to be controlled individually while connected to a single channel of receiver 16 ′. In one example, the controller 16 ′ communicates with the loads 43 , 44 , 46 using a DC powerline carrier signal
The systems 10 a - d of FIGS. 1-4 are applicable to a variety of environments, such as structures (e.g., residential, commercial, and industrial buildings) or outdoor spaces. FIG. 7 schematically illustrates a residential building 100 incorporating a plurality of the controllers 16 as set forth in FIG. 1 , coupled to the plurality of DC loads 18 . An electrical power source 102 supplies power through a plurality of power lines 26 to a plurality of controllers 16 . The electrical power source 102 may correspond to the AC power source 12 and power converter 14 collectively (see FIG. 1 ), the AC power source 12 on its own (see FIG. 2 ), the AC power source 12 and the first DC converter 22 collectively (see FIG. 3 ), the DC power source 40 (see FIG. 4 ), or the AC power source 12 and power converter 23 (see FIG. 5 ), for example.
The building 100 also includes a power converter 104 , which could correspond to one of the power converters 20 of system 10 b (see FIG. 2 ), one of the power converters 24 of system 10 c (see FIG. 3 ), one of the step down DC converters 42 of system 10 d (see FIG. 4 ), or one of the power converters 41 (see FIG. 5 ), for example. As shown in FIG. 6 , it is possible to place the power converter 104 at a central location in the building 100 .
Each of the controllers 16 are shown to have power lines 28 communicating with various DC loads 18 , some or all of which may correspond to luminaires including LEDs. If the DC loads 18 include LED lights, use of the systems 10 a - e enables an individual to economically provide DC power to the LED lights in the residential building 100 while avoiding use of expensive LED lights having built-in power conversion electronics. Of course, as described earlier, other DC loads could be used. Thus, it can be seen that the electrical power source (optionally in conjunction with power converter 104 ) distribute a DC voltage throughout a first portion of the building 100 environment, and the controllers 16 distribute a DC voltage throughout a second portion of the building 100 environment.
Receptacles may be coupled to the controllers 16 , which could enable an individual to avoid having to use AC adapters to provide DC to electronic items. Also, “smart plug” receptacles operable to convert DC to AC could also be used to so that only DC wiring would be needed in the structure 100 .
Although embodiments of this invention have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.