Method and apparatus for isolating high voltage power control elements

(57) Abrégé/Abstract:

The devices and methods described below provide for a high voltage control circuits using commercial lower voltage, and lower cost, relays. A low voltage control system using commercial switching relays is used to control and switch an isolated low voltage

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OPIC-CIPO 191

CA 2843350 C 2016/09/06 (57) Abrégé(suite)/Abstract(continued):

power supply through an isolation layer. The isolated low voltage power supply is used to drive commercial switching relays that control the high voltage power applied to the high voltage load. Adding the isolated low voltage power supply controlled through an isolation layer enables the use of commercial low voltage components to switch high voltage power such as 347VAC without violating Underwriters Laboratories spacing or testing requirements.

¢11)(21) 2 843 350 (13) C

-2CA 02843350 2014-01-27 (12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)

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(19) World Intellectual Property Organization International Bureau (43) International Publication Date

January 2013 (31.01.2013)

WIPO I PCT

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIN (10) International Publication Number

WO 2013/016550 A3 (51) International Patent Classification: (81)

G05F1/10 (2006.01) (21) International Application Number:

PCT/US2012/048360 (22) International Filing Date:

July 2012 (26.07.2012) (25) Filing Eanguage: English (26) Publication Eanguage: English (30) Priority Data:

61/512,323 27 July 2011 (27.07.2011) US

13/559,198 26 July 2012 (26.07.2012) US (71) Applicant (for all designated States except US): THE WATT STOPPER, INC. [US/US]; 2215 Faraday Ave., Suite E, Carlsbad, CA 92008-1211 (US).

(72) Inventor; and (75) Inventor/Applicant (for US only): BETANCOURT, Erick [US/US]; 2215 Faraday Ave., Suite E, Carlsbad, CA 92008-1211 (US).

(74) Agent: BACKOFEN, Paul, J.; Crockett &amp; Crockett, PC, 26020 Acero, Suite 200, Mission Viejo, CA 92691 (US).

Designated States (unless otherwise indicated, for every kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SC, SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.

(84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, SZ, TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, ΓΓ, LT, LU, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG).

Published:

— with international search report (Art. 21(3)) (88) Date of publication of the international search report:

June 2013 (54) Title: METHOD AND APPARATUS FOR ISOLATING HIGH VOLTAGE POWER CONTROL ELEMENTS

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WO 2013/016550 A3 (57) Abstract: The devices and methods described below provide for a high voltage control circuits using commercial lower voltage, and lower cost, relays. A low voltage control system using commercial switching relays is used to control and switch an isolated low voltage power supply through an isolation layer. The isolated low voltage power supply is used to drive commercial switching relays that control the high voltage power applied to the high voltage load. Adding the isolated low voltage power supply controlled through an isolation layer enables the use of commercial low voltage components to switch high voltage power such as 347VAC without violating Underwriters Laboratories spacing or testing requirements.

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Method and Apparatus for Isolating High Voltage Power Control Elements

Field of the Inventions

The inventions described below relate the field of electrical controls and more specifically, controls for high voltage relay drive circuits for controlling electrical loads.

Background of the Inventions

High voltage relays require physical isolation for safe operation. Underwriters Laboratories has recently increased its spacing and testing requirements for 347VAC systems. Underwriters Laboratories requires that a certain physical spacing exist between high voltage and any part that could come into contact with a person e.g., an installer or user. Typically, Underwriters Laboratories considers lower voltage circuits, typically 42.5VDC or less and 30VAC or less, to be contactable by a person. Common commercial relays violate the high voltage spacing requirement because the distance from the low voltage coil contacts to the high voltage relay contacts is generally less than the required minimum spacing.

Special relays are available that are Underwriters Laboratories listed for 347VAC operation, but those relays are much larger to meet the spacing requirements, cost three to four times as much as a common commercial relay, and are often a latching-type relay that may not be desired.

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In a relay control circuit a low voltage coil, e.g., 624V DC or AC, is driven from a low voltage control circuit to establish a current in the coil, thereby establishing a magnetic field that pulls a relay contact armature connected to one high voltage contact toward another open high voltage contact, thereby causing the relay contacts to close and establish a closed high voltage circuit. This allows a high voltage supply on one relay contact to be connected to a load connected to the other contact for the purpose of controlling power to the load. 24VDC is a very common operating voltage in lighting controls, so it is common to find the relay coil being driven from a 24V supply. Most commercial relays are Underwriters Laboratories listed or rated for common U.S. operating voltages, e.g., 120VAC or 277VAC, because the physical spacing between the low voltage coil and the high voltage relay contacts meets Underwriters Laboratories spacing requirements, but those spacings are not suitable for control of 347VAC.

Summary

The devices and methods described below provide for a high voltage control circuits using commercial lower voltage, and lower cost, relays. A low voltage control system using commercial switching relays is used to control and switch an isolated low voltage power supply through an isolation layer. The isolated low voltage power supply is used to drive commercial switching relays that control the high voltage power applied to the high voltage load. Adding the isolated low voltage power supply controlled through an isolation layer enables the use of commercial low voltage components to switch high voltage power such as 347VAC without violating Underwriters Laboratories spacing or testing requirements.

In an isolated high voltage control circuit as described, for example 24VDC, conceptually all elements of the isolated

CA 02843350 2014-11-14

76452-96PPH control power circuit are exposed to high voltage from a Underwriters Laboratories testing perspective. Rather than use an exposed low voltage supply to power the relay coil of the isolated power circuit, an isolated 24VDC supply is used. In order to still allow control by low voltage control circuitry, optical isolators or other suitable isolation components are used to send the control signal from the exposed low voltage system across a suitable isolation barrier, e.g., optical isolation, to the isolated high voltage system to control the hot relay coil. Since the isolated relay coil and isolated relay contacts are both considered to be located on the high voltage side of the circuit, it is possible to use a common commercial relay in an isolated high voltage application. This saves considerable cost and allows smaller commercial relays to be used, thereby allowing products to be made smaller, e.g., suitable for mounting inside of a standard junction box as is required by certain municipality building codes.

In an aspect, there is provided a high voltage power control system comprising: a low voltage control system having a first low voltage power supply producing a low voltage control signal which is controlled by a first control element producing one or more low voltage control signals which are applied to an isolation element to produce one or more high voltage control signals; and an'isolated control system having a second low voltage power supply producing an isolated low voltage control signal which is controlled by a second control element under control of the one or more high voltage control signals to produce one or more load control signals which are applied to a load control element which controls the

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6452-96PPH application of high voltage energy from a high voltage power supply to one or more high voltage loads.

There is also provided the high voltage power control system as described above wherein the isolation element comprises: an optical isolator.

There is also provided a method of controlling a high voltage power control system comprising the steps: providing a low voltage control system having a first low voltage power supply and a first control element; providing an isolated control system having a second low voltage power supply and a second control element; providing an isolation element operably connected between the low voltage control system and the isolated control system; providing a load control element operably connected to the isolated control system; the first control element producing one or more low voltage control signals; applying the one or more low voltage control signals to the isolation element to produce one or more high voltage control signals; applying the one or more high voltage control signals to the second control element to produce one or more load control signals; and applying the one or more load control signals to the load control element which controls the application of high voltage energy from a high voltage power supply to one or more high voltage loads.

There is also provided a method of controlling a high voltage power system comprising the steps: providing a low voltage control system having a first control element; providing an isolated high voltage control system having an isolated low voltage power supply and a second control element; providing an isolation element operably connected between the

3a

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76452-96PPH low voltage control system and the high voltage control system; applying a first low voltage control signal to the first control element to produce one or more low voltage control signals; applying one or more low voltage control signals to the isolation element to produce one or more high voltage control signals; applying the one or more high voltage control signals to the second control element to produce one or more load control signals; and applying the one or more load control signals to a load control element which controls the application of high voltage energy from a high voltage power supply to one or more high voltage loads.

There is also provided a high voltage power control system comprising: a low voltage control system producing one or more low voltage control signals; an isolation element converting the one or more low voltage control signals into one or more high voltage control signals; and an isolated control system producing an isolated low voltage control signal which is converted by a control element under control of the one or more high voltage control signals to produce one or more load control signals which control the application of high voltage energy from a high voltage power supply to one or more high voltage loads.

Brief Description of the Drawings

Figure 1 is a block diagram of a multilayer isolated power control system.

Figure 2 is a schematic diagram of the isolated low voltage power supply of Figure 1.

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Detailed Description of the Inventions

In Figure 1, multilayer power control system 10 includes first control system 12 which is a low voltage control system which controls high voltage power system 14 through isolation element 16. Low voltage control system 12 includes low voltage power supply 12P and control element 17 which produces low voltage control signals 13. Control element 17 may be any suitable user control such as a button, switch, relay or other electrical switching apparatus. Some or all of 10 the elements

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WO 2013/016550 PCT/US2012/048360 of low voltage control system 12 may be enclosed in a conventional junction or switch box. Isolation element 16 may be any suitable control signal isolator such as an optical isolator. Isolation element 16 isolates and converts low voltage control signal 13 into one or more isolated control signals 13H which are applied to high voltage power system 14.

High voltage power system 14 is a control system that includes isolated low voltage power supply 18 and an isolated switching or control element such as relay 19. The isolated control element may be a single component such as relay 19, or it may be any suitable switching or control circuit such as a transistor switching circuit, a triac switching circuit, a silicon controlled switching circuit or an optical isolator switching circuit.

Power supply 18 is illustrated in Figure 2 and applies control power 18C from terminals 15A and 15B, to relay 19 which is controlled by isolated control signals 13H to produce control signals 19C which are applied to a load switching element such as load relay 22 which switches high voltage power from high voltage supply 20 to load 21. Input protection component 23, such as a metal oxide varistor or a choke, may be placed in power supply 18 between the line and neutral connections, connections 24 and 25 respectively, and the inputs at R164 and D36. Resistors 178 and 179 in combination with zener diode Z8 drive MOSFET Q34 on when switcher U15 is on. MOSFET Q34 provides about 500 volts of additional voltage breakdown capacity to switcher U15.

Power and control components 18, 19 and 22 are commercial low voltage components which may be used because they are isolated in high voltage system 14. High voltage supply 20 and high voltage load 21 may be controlled by less expensive low voltage components 18, 19 and 22 if the low voltage components are isolated from users.

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While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. The elements of the various embodiments may be incorporated into each of the other species to obtain the benefits of those elements in combination with such other species, and the various beneficial features may be employed in embodiments alone or in combination with each other. Other embodiments and configurations may be devised with departing from the scope of the appended claims. The scope of the claims should not be limited by the examples herein, but should be given the broadest interpretation consistent with the description as a whole.

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