Light-energized electronics energy management system

• US 5,229,649 A
• Filed: 10/04/1988
• Issued: 07/20/1993
• Est. Priority Date: 09/28/1988
• Status: Expired due to Term

• Current Assignee: Ambient Control Systems, Inc.
• Original Assignee: Solatrol, Inc.
• Inventors: Luck, Jonathan M., Nielsen, Wyn. Y.
• Primary Examiner(s): Scott, J. R.
• Assistant Examiner(s): Logan, Sharon D.
• Application Number:
  US07/253,858
• Time in Patent Office: 1,750 Days
• Field of Search: 307/31, 307/44, 307/66, 239/63, 239/69, 239/70, 250/206
• US Class Current: 307/31
• CPC Class Codes: A01G 25/16 Control of watering
• CPC Class Codes: G06F 3/0489 using dedicated keyboard keys or combinations thereof
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02P 60/12 using renewable energies, e.g. solar water pumping

Abstract

An irrigation controller is powered for all normal operations by light incident upon an 18 square inch photovoltaic module. Electrical power from the photovoltaic module is stored in high performance "super" capacitors. A transportable battery power source is connected to the controller to power its communication, such as for manual exercise and/or the loading of irrigation control programs. The external battery power source leaves the capacitor power storage recharged at the conclusion of each communication episode. The irrigation controller electronics, save for a real time clock that is updated, are not provided with a timing signal, and thereby consume almost no energy, save for brief millisecond sporadic time intervals of scheduled irrigation control. Capacitor power storage is approximately 6.5 mWH. Worse case photovoltaic energy production is 7.6 mWH daily. The sporadically operative irrigation controller uses less than 6.4 mWH per day, with remaining energy expended on up to 128 ultra-low-power valve actuations per day.

Claims

1. An apparatus comprising:

operational means for at times performing a function other than communication that consumes power at a first rate, and for at other times performing a communication function that consumes power at a second rate higher than the first rate;

means for deriving electrical energy from radiant energy incident upon the apparatus;

means for storing electrical energy, received from the means for deriving, sufficient so as to power the operational means at the first rate for the function other than communication;

connection means for electrically connecting the operational means to an external source of power selectively during all such times as the operational means is performing the communication function;

wiring means for constantly electrically connecting the operational means to the means for storing electrical energy;

transportable power source means, electrically connected to the operational means by the connection means during all such times as the operational means is performing the communication function, for serving as the external source of power for powering the operational means at the relatively-higher second rate;

wherein the powering of the operational means for the communication function by the transportable power source means permits that this communication function, which uses power at the relative-higher second rate, may transpire without substantial diminution of the energy stored in the means for storing energy.

2. The apparatus according to claim 1 wherein the means for storing comprises:

a capacitor.

3. The apparatus according to claim 2 wherein the capacitor comprises:

an electrolytic capacitor having at least one carbon paste electrode.

4. The apparatus according to claim 2 wherein the capacitor comprises:

a large capacitance electric double layer capacitor storing charge at an interface by an electric field between one phase comprising an activated carbon particle and a second phase comprising sulfuric acid.

5. The apparatus according to claim 1 wherein the transportable power source means comprises:

a battery.

6. The apparatus according to claim 1 adapted as an irrigation controller that at times performs as the function other than communication an irrigation control function that consumes power at the first rate, and that at other times performs the communication function that consumes power at the second rate in order to communicate with a user/programmer of the irrigation controller so that the user/programmer may direct the irrigation controller in the control of irrigation, the apparatus according to claim 1 so adopted wherein the operation means comprises:

a microprocessor;

wherein the means for deriving comprises;

a photovoltaic device deriving electrical energy from light energy;

wherein the means for storing comprises;

a capacitor;

wherein the connection means comprises;

a pluggable electrical connector; and

wherein the transportable power source means comprises;

a battery.

7. The apparatus according to claim 1 wherein the transportable power source means is connected in electrical parallel with the means for storing by the connector means, and thus not only serves as the source of power to powering the operational means without substantial diminution of the power stored in the means for storing, but, because it is connected in electrical parallel with the means for storing by the connector means that at all times connects the means for storing to the operational means, actually replenishes power stored in the means for storing.

8. The apparatus according to claim 1 wherein the means for deriving comprises:

a photovoltaic power source for producing voltage in the presence of light energy; and

wherein the means for storing comprises;

a capacitor for accumulating electrical charge in response to the voltage developed by the photovoltaic power source.

9. The apparatus according to claim 1 wherein the operational means comprises:

clock means, consuming insignificant power from the means for storing electrical energy, for keeping time;

computer means for performing at all times as the function other than communication a computational function, not including timekeeping, that consumes power at the first rate, and for performing at other times the communication function that consumes power at the second rate;

power gating means, responsive to the time kept by the clock means, for interrupting power supplied to the computer means by the means for storing electrical energy during substantial periods when the computer means is performing the computational function, the power gating means being without any effect on (i) the continuous supply of power to the clock means by the means for storing electrical energy, and (ii) the supply of power to the computer means and to the clock means from the transportable power source means through the connection means;

wherein the means for deriving and the means for storing are facilitated to power the operational means at the first rate for the computational function because the operational means, although continuously powered, exhibits substantial periods when insignificant power is used.

10. The apparatus according to claim 1

wherein the connector means is actuated for selectively electrically connecting the transportable power source means to the operational means by a manual plugging of the transportable power source means to the operational means;

wherein because the connector means selectively connects the operational means to the transportable power source means during all times that the operational means is performing its communication function, and because the selective electrical connection is actuated by manual plugging, then the duration of the manual plugging of the transportable power source means to the operational means defines the time interval of the communication function of the operational means.

11. A method of powering a system that at times performs a function other than communication that consumes power at a first, relatively lower rate, and that at other times performs a communication function that consumes power at a second, relatively higher, rate, the method comprising:

deriving electrical energy from radiant energy incident upon the system;

storing the electrical energy;

powering the system at the relatively lower first rate for the function other than communication from the stored electrical energy;

electrically connecting a transportable power source to the system during all such times as it performs the communication function;

powering the system at the relatively higher second rate for the communication function from the electrically connected transportable power source.

12. A system for storing energy from light as electrical charge comprising:

a photovoltaic power source for producing voltage in the presence of light energy;

a diode connected to the photovoltaic power source;

a capacitor connected through the diode across the photovoltaic power source for accumulating electrical charge in response to the voltage developed by the photovoltaic power source;

a voltage sensor, connected across the capacitor for producing a control signal when the charge upon the capacitor exceeds a predetermined reference level;

a delay circuit, connected to the voltage sensor for receiving the control signal therefrom, for delaying in time the control signal in order to produce a delayed control signal; and

a controllable electrical shunt circuit, connected across the photovoltaic power source and receiving the delayed control signal from the delay circuit, for short circuiting the voltage produced by the photovoltaic power source selectively during receipt of the delayed control signal.

13. The system according to claim 12 wherein the photovoltaic power source comprises:

two photovoltaic modules connected in series to each other at a common terminal of each;

wherein the diode comprises;

two diodes, each connected in an opposite polarity to a remaining terminal of a respective one of the two photovoltaic modules;

wherein the capacitor comprises;

two capacitors connected in series to each other and each connected through a respective one of the two diodes to a respective one of the two photovoltaic modules, a common terminal of the series-connected capacitors being connected to the common terminal of the series-connected photovoltaic modules;

wherein the voltage sensor comprises;

two voltage sensors, each connected across a respective one of the two capacitors, for each producing a respective control signal when the charge upon the respective capacitor exceeds a respective predetermined reference level;

wherein the delay circuit comprises;

two delay circuits, each connected to a respective one of the two voltage sensors for receiving the respective control signal therefrom, for each delaying in time the respective control signal to produce a respective delayed control signal; and

wherein the controllable electrical shunt circuit comprises;

two controllable electrical shunt circuits, each connected across a respective one of the two photovoltaic modules and each receiving a respective delayed control signal from a respective one of the two delay circuits, for each short circuiting the voltage produced by a respective one of the two photovoltaic modules selectively during receipt of the respective delayed control signal.

14. The system according to claim 12 wherein the photovoltaic module comprises:

amoprhous silicon.

15. The system according to claim 12 wherein the capacitors comprise:

supercaps, meaning capacitors each having a capacitance greater than 0.2 farad.

16. A method of electrically powering a device that quiescently uses electrical power of a relatively lessor rate but which responds to asynchronous demands to use electrical power at a relatively greater rate, the method comprising:

photoconverting light energy into first electrical power;

continuously first-supplying the first electrical power to the device from the photoconverting of light energy into electrical power, the photoconverting and the first supplied first electrical power being sufficient to supply electrical power at a relatively lesser rate to maintain quiescent operation of the device through periods of light and darkness, but being insufficient to reliably satisfy asynchronous demands upon the device to use electrical power of a relatively greater rate, especially if such demands occur during periods of darkness;

providing second electrical power from a source of electrical power; and

selectively second-supplying the second electrical power to the device from the source only upon, and for the duration of, each asynchronous demand that the device should use electrical power at a relatively greater rate, the source suppling the electrical power at the relatively greater rate during the duration of demand for same.

17. The method according to claim 16 further comprising:

manually connecting and disconnecting the source of electrical power to the device;

wherein the selectively second-supplying is in response to asynchronous demands that are initiated and terminated by act of manually connecting and disconnecting the source;

wherein the origin of an asynchronous demand to use electrical power at a relatively greater rate is resultant from the connection of the same source that provides this electrical power at the relatively greater rate.

18. The method according to claim 17 wherein the second-supplying is from a portable battery energy source.

19. A dual-sourced circuit for receiving and storing electrical power comprising:

a first source of power including a battery-powered source of direct current;

a second source of power including a photovoltaic power source, connected in electrical parallel with the first source of power and diode isolated therefrom, for providing direct current during periods of exposure to light;

an energy storage means for storing electrical power; and

an energy storage control means, connecting the electrically parallel first and second sources of power to the energy storage means, for gating direct current from both the first source of power and the second source of power to the energy storage means until the energy storage means stores a predetermined amount of electrical power.

20. The circuit according to claim 19 further comprising:

a voltage regulator connected to the energy storage means for supplying energy stored therein to a load at a predetermined voltage level.

21. The circuit according to claim 20 further comprising:

a voltage monitoring circuit connected to the voltage regulator for providing an alarm signal upon such times as the predetermined voltage level supplied by the voltage regulator to the load is outside of a predetermined voltage range.

22. The circuit according to claim 19 wherein the battery-powered source of direct current is current regulated.

23. The circuit according to claim 22 wherein the battery-powered source of regulated direct current comprises:

a battery source of direct current;

a switching regulator connecting to the battery for regulating direct current received therefrom to produce regulated direct current.

24. The circuit according to claim 19 wherein the energy storage means comprises:

a capacitor for storing energy as electrical charge.

25. The circuit according to claim 24 wherein the energy storage control means comprises:

a diode, connected between the electrically parallel first and second sources of power and the capacitor;

a voltage sensor, connected across the capacitor, for producing a control signal when the electrical charge upon the capacitor exceeds a predetermined reference level;

a delay circuit, connected to the voltage sensor for receiving the control signal therefrom, for delaying in time the control signal in order to produce a delayed control signal; and

a controllable electrical shunt circuit, connected across the electrically parallel first and second sources of power and receiving the delayed control signal from the delay circuit, for short circuiting the voltage produced by the first and the second sources of power selectively during receipt of the delayed control signal.

26. An irrigation controller comprising:

power means for providing power;

control means, consuming when operating a first rate of electrical power, for conducting irrigation cycles at timed intervals, and for time durations, that are both determined by elapsed real time, when and if operatively powered at the first rate to so conduct irrigation cycles;

clock means, consuming a second rate of electrical power that is lower than the first rate, constantly operative for keeping the elapsed real time by which the irrigation cycles may be conducted by the control means; and

power enablement means responsive to the clock means for selectively gating power at the first rate from the power means to the control means upon, and for duration of, the timed intervals;

wherein the selective gating of power by the power enablement means permits that the control means is operatively powered at the first rate to conduct irrigation cycles only at intervals, and is otherwise unpowered.

27. A light-energized irrigation system controller characterized by low energy use, the controller comprising:

a photovoltaic module

(i) installable in geographic locations at times of the year and at illumination levels due to sun angle and atmospheric conditions,

(ii) installable in locations with partially obstructed skyview, and

(iii) having a collection area, a light transmission loss, and a light to energy conversion technology, that are collectively such as to provide a worst case diurnal energy collection ability of less than 10 mwH;

an energy storage means receiving the energy collected by the photovoltaic module and, upon such times as that energy is less than 10 mwH, storing that energy without leaking away more than 4 mwH in any 24 hour period -10°

C. to 70°

C., therein making that from 0 to 6 mwH are available to do productive work upon a worst case energy collection;

a programmable irrigation controller controlling a plurality of valves, the irrigation controller and the plurality of valves all powered exclusively by the energy storage means, wherein the combined daily energy consumption of the controller and the values for up to sixteen complete cycles of each valve is in total less than 6 mwH;

therein making that an irrigation system controller is energizable exclusively by light energy diurnally collected at levels as low as 10 mwH.

28. An electrically-powered irrigation controller comprising:

a clock;

logic circuitry for producing electrical signals useful to control the conduct of irrigation; and

means responsive to the clock for disabling a substantial amount of the logic circuitry between certain diurnal time periods when functioning of the logic circuitry is enabled, the logic circuitry consuming negligible power while disabled.