A power supply system for harvesting power from an electric cable

Abstract

A power supply that extracts power from the electromagnetic field around an electric cable of an electric grid in a wide range of current through the electric cable. The power supply includes a plurality of power supply modules connected in parallel over the same input ferromagnetic core, and over the same output condenser. The power supply modules have a different number of windings over the ferromagnetic core, and a short-circuit is applied on the winding of each power supply module when the output voltage exceeds the allowable value for the particular power supply module.

Description

[0001] A POWER SUPPLY SYSTEM FOR HARVESTING POWER FROM AN ELECTRIC CABLE

[0002] FIELD

[0003] The method and apparatus disclosed herein are related to the field of power supplies deriving input electric power from the electromagnetic field surrounding an electric cable of an electric grid, such as a cable of an electric transmission network and / or a distribution network.

[0004] BACKGROUND

[0005] Power supplies providing controlled voltage or current are well known. Such power supplies are commonly designed for a particular limited range of input voltage, or a particular limited range of input current.

[0006] Power supplies for devices hanging from an electric cable of an electric grid, such as electric transmission and / or distribution networks, are not connected to any mains power, and therefore have to derive their input power from the electric field, and / or the magnetic field, surrounding the electric cable. Such electromagnetic field depends on the current flowing through the electric cable. Such current may vary by several orders of magnitude. Common power supplies are not designed to feed on such a wide range of input current. It would therefore be highly advantageous to have a power supply deriving input electric power from the magnetic field surrounding an electric cable of an electric grid, devoid of the above limitations.

[0007] SUMMARY

[0008] According to one exemplary embodiment there is provided a system and a method for power supply including a ferromagnetic core configured to receive therewithin an electric cable of an electric grid the electric cable carrying an electric current I, and an output condenser Cout configured to be electrically coupled to an electric load. The power supply further includes a first power supply module PSA and a second power supply PSN.

[0009] The first power supply module includes a secondary winding WA, wound on the ferromagnetic core, and a rectifier part having an input and an output. The input is electrically coupled to the secondary winding WA, and the output is electrically coupled to the output condenser Cout, and a short circuit circuitry having an input and an output. The input of the short circuit circuitry is electrically coupled to the output condenser Cout, and the output is electrically coupled to the secondary winding WA and is operative to apply a short circuit on the secondary winding WA.

[0010] The second power supply module PSN includes a secondary winding WN, wound on the same ferromagnetic core, a rectifier part having an input and an output, where the input is electrically coupled to the secondary winding WN, and where the output is electrically coupled to an internal capacitor Ci, a DC-to-DC converter circuit having an input and an output, where the input is electrically coupled to the internal capacitor Ci, and where the output is electrically coupled to the same output condenser Cout, an enabling control circuit having an input and an output, where the input is electrically coupled to the capacitor Ci, and where the output is electrically coupled to the control terminal of the DC-to-DC converter circuit, and a short circuit circuitry having an input and an output, where the input is electrically coupled to the same output condenser Cout, and where the output is electrically coupled to the secondary winding WN and is operative to apply a short circuit on the secondary winding WN.

[0011] According to another exemplary embodiment the winding WN includes more windings than winding WA.

[0012] According to yet another exemplary embodiment the second power supply module PSN includes a plurality of second power supply modules PSI to PSN, each having a respective winding W1 to WN wound on the same ferromagnetic core, and where the winding WN has more windings than the winding WN-1, and the winding W1 has more windings than the winding WA.

[0013] According to still another exemplary embodiment each of the power supply modules PSI to PSN is configured to operate in a different current operating range of the electric current I.

[0014] Further, according to another exemplary embodiment a short circuit is applied to the secondary windings WN of each of the respective rectifier part if the electric current I is higher than the respective current operating range. Still further according to another exemplary embodiment the power supply module PSA is operative to work in pulse-width-modulation mode including two states, a charging state, and a discharging state where in the discharging state the short circuit circuitry applies a short circuit on the secondary winding WA.

[0015] Yet further according to another exemplary embodiment the power supply module PSA is operative to work in pulse-width-modulation mode when all power supply modules PSN have their respective short circuit circuitry applying a short circuit on their secondary windings WN respectively.

[0016] Even further according to another exemplary embodiment the enabling control circuits of power supply modules PSN are operative to activate their respective DC-to-DC converter circuits when voltage on respective internal capacitor CIN is VCIN-HIGH and deactivate the respective DC-to-DC converter circuit when voltage on respective internal capacitor CIN is VCIN-LOW, where VCIN-HIGH is larger than VCIN-LOW; and where VCIN-LOW of power supply module PSN-1 is larger than VCIN-HIGH of power supply module PSN.

[0017] Yet, according to another exemplary embodiment the DC-to-DC converter circuit of power supply module PSN-1 is operative to provide output voltage that is higher than output voltage of DC-to-DC converter circuit of power supply module PSN.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the relevant art. The materials, methods, and examples provided herein are illustrative only and not intended to be limiting. Except to the extent necessary or inherent in the processes themselves, no particular order of steps or stages of methods and processes described in this disclosure, including the figures, is intended or implied. In many cases the order of process steps may vary without changing the purpose or effect of the methods described.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various embodiments are described herein, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the embodiments only, and are presented in order to provide what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the embodiment. In this regard, no attempt is made to show structural details of the embodiments in more detail than is necessary for a fundamental understanding of the subject matter, the description taken with the drawings making apparent to those skilled in the art how the several forms and structures may be embodied in practice.

[0021] In the drawings:

[0022] Fig. 1 A is a simplified illustration of a power harvesting grid device mounted on an electric cable of an electric grid;

[0023] Fig. IB is a simplified illustration of three power harvesting grid devices mounted on three respective electric cables, and including a wide range power harvesting power supply;

[0024] Fig. 2 is a simplified illustration of a cut through cable device 10 mounted on an electric cable;

[0025] Fig. 3 is a simplified illustration of a plurality of windings wrapped on a magnetic core mounted on electric cable;

[0026] Fig. 4 is a simplified block diagram of power harvesting power supply;

[0027] Fig. 5 is a simplified block diagram of a type N power supply module;

[0028] Fig. 6 is a simplified block diagram of a type A power supply module;

[0029] Fig. 7 is a simplified electric diagram of type A power supply module;

[0030] Fig. 8 is a simplified electric diagram of type N power supply module;

[0031] Fig. 9 is a simplified diagram of relationships between the power supply modules in terms of power output to load capacitor;

[0032] Fig. 10A is a simplified diagram of the currents through the windings of three parallel power supply modules;

[0033] Fig. 10B is a simplified diagram of pulse width modulated current via rectifier circuitry charging load (output) capacitor;

[0034] Fig. 10C is a simplified diagram of the voltage activating the short circuit circuitry to apply a short circuit over the respective winding;

[0035] Fig. 10D is a simplified diagram of the voltage on load capacitor; Fig. 11 is a simplified diagram of relationships between the power supply modules in terms of power output to load capacitor when current 15 is decreasing; and

[0036] Fig. 12 is a simplified diagram of relationships between the voltage on the internal capacitors (CIN) and the voltage on the load capacitor, as the current through the electric cable increases.

[0037] DETAILED DESCRIPTION

[0038] The present embodiments comprise a method and a system for deriving electric power from the magnetic field surrounding an electric cable of an electric grid, where the magnetic field is produced by the electric current flowing within the electric cable, and where the value of the electric current may vary by several orders of magnitude.

[0039] Before explaining at least one embodiment in detail, it is to be understood that the embodiments are not limited in their application(s) to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. Other embodiments may be practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0040] In this document, an element of a drawing that is not described within the scope of the drawing and is labeled with a numeral that has been described in a previous drawing has the same use and description as in the previous drawings. Similarly, an element that is identified in the text by a numeral that does not appear in the drawing described by the text, has the same use and description as in the previous drawings where it was described.

[0041] The drawings in this document may not be of any scale. Different Figs, may use different scales and different scales can be used even within the same drawing. For example, different scales for different views of the same object or different scales for the two adjacent objects.

[0042] The phrases “at least one” “one or more” and “and / or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C, “at least one of A, B, or C, “one or more of A, B, and C. “one or more of A, B, or C and “A, B, and / or C means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. The terms “a” or “an entity” refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more' and “at least one' can be used interchangeably herein.

[0043] It is also to be noted that the terms ‘comprising’, ‘including’, ‘containing’, ‘characterized by’, and ‘having’ are all inclusive, open-ended, do not exclude additional, unrecited elements or method steps, and can be used interchangeably. Particularly, these terms may imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” and “comprises”.

[0044] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic that is described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment, and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0045] The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

[0046] The term ‘grid’, or ‘electric grid’, may refer to the electric transmission network and / or the electric distribution network, and to any part of such network between the power generating station, or stations, or electric storage station, or stations, and the load, or the consumer, or consumers. Such a grid may include any number of electric cables, carrying electric voltage, and / or electric current.

[0047] The term ‘electric cable’, or ‘phase carrying cable’, or simply ‘cable’, may refer to any cable of the electric grid. Such cable may be referred to as power line, or feeder, etc. Such cable may be generating an electromagnetic field around the cable. Such electromagnetic field may contain an electric field and a magnetic field.

[0048] The term ‘power harvesting’ may refer to an electric power supply deriving input power from the electromagnetic field around an electric cable and supplying controlled electric power to an electric circuitry or any other electric load. The harvested electromagnetic field may contain an electric field and a magnetic field. Such power harvesting power supply may derive power from the electric field or the magnetic field around the cable, and supply controlled voltage or controlled current, to the load.

[0049] Reference is now made to Fig. 1 A and Fig. IB, which are simplified illustrations of a power harvesting grid device 10 mounted on an electric cable 11 of an electric grid 12, according to one exemplary embodiment. Power harvesting grid device 10 (device 10 for shot) may include a wide range power harvesting power supply 13, that may harvest power from the magnetic field 14 generated by the electric current 15 flowing through cable 11. This electric current 14 may have a very wide range of values, which may reach several orders of magnitude.

[0050] As shown in Fig. IB, the cable device 10 may include a box, or a body 16, through which the electric cable 11 passes. The cable device 10 may therefore be mounted on a live cable 11. That is, when cable 11 is fully powered and / or carries electric voltage and / or electric current.

[0051] The box 16 is therefore constructed of two parts which may be opened, and then closed around the cable 11. Alternatively, box 16 may be constructed of one part surrounding most of the cable diameter and having an opening at one side, such as slot 17 to insert cable 11 and attach the box to cable 11.

[0052] Reference is now made to Fig. 2, which is a simplified illustration of a cut through cable device 10 mounted on an electric cable 11, according to one exemplary embodiment.

[0053] As an option, the illustration of cable device 10 of Fig. 2 may be viewed in the context of the details of the previous Figures. Of course, however, the illustration of cable device 10 of Fig. 2 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0054] As shown in Fig. 2, the cable device 10 may include power harvesting power supply 13, which may include any number of power supply modules 18. The input of each of the power supply modules 18 may be electrically coupled to a respective winding 19. Winding 19 may be a coil that is wrapped on a magnetic core 20.

[0055] The magnetic core 20 may be mounted around the electric cable 11. The magnetic core 20 may be constructed from two parts, a part in each of the two parts of box 16 where the two parts of the magnetic core 20 are closed around electric cable 11 when box 16 is attached to electric cable 11 and closed.

[0056] However, optionally, and particularly for a high voltage cable, magnetic core 20 may be open in the sense that it has a slot though which electric cable 11 may be inserted, where the slot is not closed with a second part of the magnetic core 20.

[0057] The magnetic core 20 typically derives magnetic field from the electric current flowing in the electric cable 11. Winding 19 typically derives electric current from the magnetic flux in the magnetic core 20. Winding 19 may be electrically coupled to power supply module 18, typically providing electric voltage to other modules of cable device 10. It is appreciated that cable device 10, and / or power harvesting power supply 13, and or any of power supply modules 18, may derive electric power from a single electric cable 11.

[0058] Fig. 2 shows power harvesting power supply 13 including two power supply modules 18 electrically coupled via respective windings 19 to a magnetic core 20. However, power harvesting power supply 13 may have any number of power supply modules 18. Such configuration of multiple power supply modules 18 with their respective windings 19 wrapped around the same single magnetic core 20 is further explained below.

[0059] Reference is now made to Fig. 3, which is a simplified illustration of a plurality of windings 19 wrapped on a magnetic core 20 mounted on electric cable 11, according to one exemplary embodiment.

[0060] As an option, the illustration of Fig. 3 may be viewed in the context of the details of the previous Figures. Of course, however, the illustration of Fig. 3 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0061] As shown in Fig. 3, magnetic core 20 may be shaped as a doughnut or a similar shape having a hole 21 within which cable 11 may pass through. Fig. 3 shows cable 11 as a plurality of metallic wires grouped together, as is commonly used. However, other types and shapes of cable 11 and magnetic core 20 are contemplated.

[0062] Magnetic core 20 may have two parts. Part 20A may include a slot 22 for mounting magnetic core 20 on cable 11. Part 20B may then be used to close the slot 22 and complete the doughnut shape of core 20. Fig. 3 shows part 20A and part 20B closed together and touching (or not touching) each other after mounting magnetic core 20 on cable 11. It is appreciated that parts 20A and 20B may be separated to allow cable 11 to pass through slot 22.

[0063] As a non-limiting example, Fig. 3 shows four windings 19 wrapped on a magnetic core 20. The four windings are enumerated 19A, 19B, 19C, and 19D. Each of the windings 19 may have a pair of electircal contacts 23, enumerated 23 A, 23B, 23C, and 23D, to be electrically coupled to the input terminals of a respective power supply modules 18 (not shown in Fig. 3). It is appreciated that any number of windings 19 is possible and contemplated.

[0064] Windings 19 may be made from a conductive wire where each windings 19 may have a different number of turns (loops) of the wire. As a non-limiting example, the number of turns (loops) of the wire of winding 19D wrapped around core 20 is twice the number of turns of winding 19C, which is twice the number of turns (loops) of winding 19B, which is twice the number of turns of winding 19A. It is appreciated that any ratio between the number of turns (loops) of any two windings 19 is possible and contemplated. Optionally, the width, or gauge, of the wire making the windings 19 may be different between the windings 19.

[0065] Magnetic core 20, cable 11, and windings 19, taken together may be viewed as an electric transformer, for example, a current transformer, where cable 11 may serve as the primary winding, and each of windings 19 may serve as the secondary winding.

[0066] Returning to Fig. 2, the cable device 10 may include a controller, or processing module 24, one or more electric measuring devices 25, one or more physical measuring devices 26, and a backhaul communication module 27. Optionally, the cable device 10 may also include a local area communication module 28, a remote sensing module 29, and a propulsion control module 30. Optionally, the cable device 10 may also include cable a clamping part 31, and a GPS module 32.

[0067] Backhaul communication module 27 and local area communication module 28 may be coupled, each and / or both, to one or more antennas 33. Remote sensing module 34 may be coupled to and control various sensors, one or more cameras 35, one or more microphones 36, etc. It is appreciated that a camera can be mounted on a system of axels providing three- dimensional rotation. Alternatively, a plurality, or an array, of fixed cameras can be mounted to cover a large field of view as needed.

[0068] Backhaul communication module 27 and local area communication module 28 may use any type of communication technology and / or communication network such as, but not limited to: The terms ‘communication technology’, or ‘communication network’, or simply ‘network’ refer to any type of communication medium, including but not limited to, a fixed (wire, cable) network, a wireless network, and / or a satellite network, a wide area network (WAN) fixed or wireless, including various types of cellular networks, a local area network (LAN) fixed or wireless including Wi-Fi, and a personal area network (PAN) fixes or wireless including Bluetooth, ZigBee, and NFC, power line carrier (PLC) communication technology, etc. The terms ‘communication network’, or ‘network’ may refer to any number of networks and any combination of networks and / or communication technologies.

[0069] Optionally, cable device 10 may also include a global positioning service (GPS) module 32 and may use it to measure, monitor, and / or control the position of the cable device 10 along electric cable 11. GPS module 32 may also provide an accurate universal clock, for example, for accurately determining absolute time of measurement.

[0070] Controller module 24 may include a processor unit, one or more memory units (e.g., random access memory (RAM), a non-volatile memory such as a Flash memory, etc.), one or more storage units (e.g. including a hard disk drive and / or a removable storage drive, etc.) as may be used to store and / or to execute a software program and associated data and to communicate with external devices.

[0071] Propulsion control module 30 may be coupled to one or more actuating devices such as electric motor 37, which may be coupled to one or more wheels 38. Wheels 38 may be mounted on cable 11 to enable propulsion control module 30 to move the cable device 10 along cable 11 by controlling the electric motor 37.

[0072] It is appreciated that the propulsion system of cable device 10 (including, but not limited to propulsion control module 30, one or more electric motors 37 one or more wheels 38 etc.) may be operative to move cable device 10 along cable 11 and / or to rotate cable device 10 around cable 11.

[0073] It is appreciated that electric motor 37 represents herein any type of technology adequate to maneuver cable device 10 along and / or around cable 11, including, but not limited to, an AC motor, a DC motor, a stepper motor, a pneumatic pump and / or motor, a hydraulic pump and / or motor, or any other type of actuator.

[0074] Cable clamping part 31 may include, for example, a cable holder part 39 that may be pressed to cable 11 to firmly attach cable device 10 to cable 11. Cable holder part 39 may be maneuvered (e.g., up and down) by electrical means and / or by mechanical means such as a threaded rod 40. Threaded rod 40 may be operated by an electric actuator or by a shaft 41, or by a rod inserted into socket 42.

[0075] Cable device 10 may also include one or more voltage regulators 43 to provide operating voltages to the respective modules of cable device 10.

[0076] It is appreciated that the various components of cable device 10 as described avive with reference to Fig. 2 are but one example of the electric load, or consumers of electric power, and other constructions and components are possible and contemplated.

[0077] Reference is now made to Fig. 4, which is a simplified block diagram of power harvesting power supply 13, according to one exemplary embodiment.

[0078] As an option, the block diagram of Fig. 4 may be viewed in the context of the details of the previous Figures. Of course, however, the block diagram of Fig. 4 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0079] Fig. 4 shows, power harvesting power supply 13 may include a plurality of power supply modules 18 connected to a respective plurality of windings 19 wrapped on a magnetic core 20. As a non-limiting example, the power harvesting power supply 13 of Fig. 4 shows three power supply modules 18 designated 18 A, 18B, and 18N. However, the power harvesting power supply 13 may include any number of power supply modules 18. As a nonlimiting example, power harvesting power supply 13 may include one power supply modules 18A (type A) and one or more power supply modules 18B to 18N, (type N) as is further described below.

[0080] For simplicity, Fig. 4 shows magnetic core 20 shaped as a straight rod, however, it should be understood that in practice core 20 is shaped as a doughnut or a similar closed shape having a hole for cable 11 (not sown in Fig. 4) as shown in Fig. 3. As a non-limiting example, Fig. 4 shows three windings 19 designated 19A, 19B, and 19N having different numbers of wire wound turns. It should be understood that windings 19A to 19N represent any number of windings 19 having different numbers of turns.

[0081] The output 23 of each windings 19A to 19N is connected to an input of a respective power supply module 18A to 18N. It should be understood that power supply modules 18 A, 18B, and 18N represent any number of power supply modules 18 that may be designated 18 A, 18B, 18C to 18N. As a non-limiting example, harvesting power supply 13 may include one power supply module 18A (of type A) and at least one power supply module 18N (of type N).

[0082] As a non-limiting example, the respective outputs of the power supply modules 18 A, 18B, and 18N may all be connected in parallel over a load capacitor (CL) 44, which may be connected via output terminals 45 of power harvesting power supply 13 to a load (RL) 46. The load 46 may represent, for example, the rest of the electronic circuitry of Fig. 2.

[0083] It is appreciated that power harvesting power supply 13 may also charge an energy storage bank such as a rechargeable battery or capacitor such as a super capacitor. For example, to serve as energy backup to the load in case of a grid power down or fault. The energy bank may hold the load for at least several minutes.

[0084] Load capacitor (CL) 44 also provides operating voltage 47 to the power supply modules 18 and to the power harvesting power supply 13 as a whole. It is appreciated that load 46 may also include a regulated power supply providing stabilized voltage, or voltages, for example, to the electronic circuitry of Fig. 2.

[0085] Reference is now made to Fig. 5, which is a simplified block diagram of power supply module 18N (type N), according to one exemplary embodiment.

[0086] As an option, the block diagram of Fig. 5 may be viewed in the context of the details of the previous Figures. Of course, however, the block diagram of Fig. 5 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0087] The block diagram of Fig. 5 may represent any of the power supply modules 18B to 18N. The letter N in the reference numbers of Fig. 5 may therefore be replaced with a any letter from B to N corresponding to the particular power supply module 18B to power supply module 18N, and representing an element of the respective power supply module (18B to 18N).

[0088] As shown in Fig. 5, power supply module 18N may include input contacts 23N connected to winding 19N (not shown in Fig. 5) and output contacts 48 connected to load capacitor (CL) 44. Input contacts 23N may represent any of input contacts 23B to 23N connected to respective winding 19B to wiring 19N.

[0089] Power supply module 18N may also include a short circuit circuitry (SCn) 49N electrically coupled to input contacts 23N. Short circuit circuitry 49N may apply a short circuit between input contacts 23N and over the respective winding 19N. Short circuit circuitry 49N may be controlled (to apply the short circuit between input contacts 23N) by a first control circuit (CTRLn) 50N according to the voltage VCL over load capacitor 44, as measured (by first control circuit (CTRLn) 50N).

[0090] Power supply module 18N may also include a rectifier circuitry (RECn) 5 IN. The input of rectifier circuitry 5 IN may be electrically coupled to input contacts 23N via short circuit circuitry 49N. The output of rectifier circuitry 5 IN may be electrically coupled to internal capacitor (Cin) 52N. Rectifier circuitry 5 IN may rectify the alternating current (AC) received from winding 19N via input contacts 23N into direct current (DC) charging internal capacitor (Cin) 52N.

[0091] Power supply module 18N may also include a DC-to-DC circuitry (DC-to-DCn) 53N. The input of DC-to-DC circuitry 53 may be electrically coupled to internal capacitor (Cin) 52N, and the output of DC-to-DC circuitry 53 may be electrically coupled via output contacts 48N to load capacitor 44.

[0092] DC-to-DC circuitry 53 may be controlled by a second, enabling, control circuit (ENn) 54N. The input of the second, enabling, control circuit 54 may be connected to internal capacitor (Cin) 52N. The second, enabling, control circuit 54 may activate and / or deactivate DC-to-DC circuitry 53 according to the voltage measured (by second, enabling, control circuit 54) over internal capacitor (Cin) 52N.

[0093] Typically, the first control circuit (CTRLn) 50N may activate the short circuit circuitry 49N to apply a short circuit over the respective winding 19N when the voltage over the load capacitor (CL) 44 is over a predefined value VSCN. Typically, the second, enabling, control circuit (ENn) 54N may activate the DC-to- DC circuitry 53 to convert the voltage provided by internal capacitor (Cin) 52N into the desired voltage over load capacitor (CL) 44 when the voltage over internal capacitor (Cin) 52N is equal or higher than VCIN-HIGH. The second, enabling, control circuit (ENn) 54N may then deactivate the DC-to-DC circuitry 53 when the voltage over internal capacitor (Cin) 52N is equal or lower than VCIN-LOW.

[0094] If is appreciated that VCIN-LOW and VCIN-HIGH may form hysteresis in which DC-to- DC circuitry 53 may operate to discharge internal capacitor 52 and charge load capacitor (CL) 44 when the short circuit is applied on terminals 23 and the voltage level on internal capacitor 52 is between VCIN-HIGH and VCIN-LOW.

[0095] Typically, the predefined values of VCIN-LOW, VCIN-HIGH, and VSCN for each power supply module 18 of power supply modules 18B to 18N, as well as the number of turns (loops) of the respective winding 19B to 19N, are arranged so that each power supply modules 18 may provide power to load capacitor 44 in a different range of the electric current 15 flowing through cable 11 (Fig. IB). Typically, these different ranges of the electric current 15 are continuous from a low current 15 for power supply module 18N to a high current 15 for power supply module 18 A.

[0096] Typically, power supply modules 18B to 18N require that load capacitor (CL) 44 is charged to a minimum operating voltage, which is electrically coupled to each of power supply modules 18B to 18N via electric connection 47, to operate circuitry such as the first control circuit (CTRLN) 50N, and the second, enabling, control circuit (ENN) 54N. Power supply module 18A may be available to operate when the voltage over load capacitor (CL) 44 is below minimum operating voltage and charge the load capacitor (CL) 44 to at least the minimum operating voltage.

[0097] Reference is now made to Fig. 6, which is a simplified block diagram of power supply module 18A (type A), according to one exemplary embodiment.

[0098] As an option, the simplified block diagram of Fig. 6 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified block diagram of Fig. 6 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below. As shown in Fig. 6, power supply module 18A may include input contacts 23 A connected to winding 19A (not shown in Fig. 6) and output contacts 48 A connected to load capacitor (CL) 44. Similar to power supply modules 18N, power supply module 18A may include a short circuit circuitry (SCA) 49A electrically coupled to input contacts 23 A. Short circuit circuitry 49 A may apply a short circuit between input contacts 23 A and over the respective winding 19 A. Short circuit circuitry 49A may be controlled (to apply the short circuit between input contacts 23 A) by a first control circuit (CTRLA) 50A according to the voltage measured over load capacitor 44.

[0099] Power supply module 18A may also include a rectifier circuitry (REC A) 51 A. The input of rectifier circuitry 51 A may be electrically coupled to input contacts 23 A via short circuit circuitry 49 A. Rectifier circuitry 51 A may rectify the alternating current (AC) received from winding 19A via input contacts 23 A into direct current (DC). However, the output of rectifier circuitry 51 A may be electrically coupled directly to load capacitor (CL) 44.

[0100] Therefore, power supply module 18A is the first to be activated and operated to charge load capacitor (CL) 44. When the voltage over load capacitor 44 reaches sufficient level all the power supply modules 18A to 18N may have operating voltage via connection 47

[0101] Reference is now made to Fig. 7, which is a simplified electric diagram of power supply module 18A (type A), according to one exemplary embodiment.

[0102] As an option, the simplified electric diagram of Fig. 7 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified electric diagram of Fig. 7 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0103] As shown in Fig. 7, power supply module 18A (type A) may include a filter circuit 55A electrically coupled between input terminals 23 A, short circuit circuitry (SCA) 49A, the first control circuit (CTRLA) 50A, and rectifier circuitry 51 A. As a non-limiting example, the filter circuit 55Amay include a resistor and a capacitor in series.

[0104] As a non-limiting example, the short circuit circuitry (SCA) 49A may include two electrically controlled switches 56 such as two thyristors, two silicon-controlled rectifiers (SCR), a triac, or a similar device. Fig. 7 shows as a non-limiting example, an implementation of the electrically controlled switch 56 using a MOSFET transistor. The electrically controlled switches 56 may be connected between ground (or common) and a respective input terminal 23 A. The control terminals of the electrically controlled switches 56 may be electrically coupled together to an output terminal of the first control circuit (CTRLA) 50A, and particularly to an operational amplifier 57 or a similar device.

[0105] As a non-limiting example, the first control circuit (CTRLA) 50A may include the operational amplifier 57A (or a similar device). A first input terminal of the operational amplifier 57A may be electrically coupled to a stable voltage source 58A (e.g. a regulated power supply), and a second input terminal of the operational amplifier 57A may be electrically coupled to a voltage divider. The voltage divider may include a first resistor 59A connected between the second input terminal of the operational amplifier 57A and the output of the rectifier circuitry 51 A, and a second resistor 60A connected between the second input terminal of the operational amplifier 57 (designated as point 61 A) and ground (or common). At least one of the first resistor 59A and the second resistor 60A may be a variable resistor to set the voltage level VSCA at which the first control circuit (CTRLA) 50A may activate the short circuit circuitry (SCA) 49A to apply a short circuit over terminals 23 A. This voltage level is a measure of the voltage over load capacitor (CL) 44, and the first control circuit (CTRLA) 50A may activate the short circuit circuitry (SCA) 49A at voltage over load capacitor (CL) 44 is over VSCA.

[0106] As a non-limiting example, rectifier circuitry 51 A may include a full bridge rectifier made of four diodes 62A. As a non-limiting example, the four diodes 62A may be Schottky diodes. Alternatively, rectifier circuitry 51 A may include a half bridge rectifier made of two diodes 62A if the switching elements 56A include their own diodes or diodes connected back-to-back.

[0107] Reference is now made to Fig. 8, which is a simplified electric diagram of power supply module 18N (type N), according to one exemplary embodiment. The simplified electric diagram of power supply module 18N may represent the electric circuitry of any of the power supply modules 18B to 18N.

[0108] As an option, the simplified electric diagram of Fig. 8 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified electric diagram of Fig. 8 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0109] The electric diagram of Fig. 8 may represent any of the power supply modules 18B to 18N. The letter N in the reference numbers of Fig. 8 may therefore be replaced with a any letter from B to N corresponding to the particular power supply module 18B to power supply modules 18N, and representing an element of the respective power supply module (18B to 18N).

[0110] As shown in Fig. 8, power supply module 18N may include the elements described with reference to power supply module 18A and additionally the internal capacitor (CIN) 52N, the DC-to-DC circuitry 53 and the second, enabling, control circuit (ENn) 54N.

[0111] Optional filter circuitry 55N may be connected to input terminals 23N, which may be connected to winding 19N. As a non-limiting example, filter circuitry 55N may include a resistor and a capacitor in series.

[0112] Short circuit circuitry 49N may be connected over filter circuitry 55N to input terminals 23N. As a non-limiting example, short circuit circuitry 49N may include a pair of MOSFET transistors 56N which include their own diodes (intrinsic diode) and is operating as electrically controlled switches, and controlled by first control circuit (CTRLn) 50N.

[0113] Like in power supply module 18 A, the first control circuit (CTRLn) 50N of power supply module 18N may include an operational amplifier 57N, which output controls MOSFET transistors 56N. One input of operational amplifier 57N may be connected to a stable voltage source 58N. A second input of operational amplifier 57N may be connected to point 6 IN between first resistor 59N and second resitor 60N.

[0114] Like in power supply module 18 A, resistors 59N and 60N form a voltage divider connected between load capacitro (CL) 44 and ground (common). Resistors 59N and 60N are used to measure voltage VCLN load capacitor (CL) 44 in which the short circuit circuitry 49N may affect a short circuit over terminals 23N. Any of the first or the second resistor may be a variable resistor (potentiometer) for tuning the threshold voltage which may activate the short circuit circuitry 49N. The short circuit threshold (activating) voltage may be different for each of the power supply modules 18A to 18N. Typically, the first control circuit (CTRLn) 50N may activate the short circuit circuitry 49N to apply a short circuit over the respective winding 19N when the voltage over the load capacitor (CL) 44 is over a predefined value VSCN. Similarly, first control circuit (CTRLn) 5 OB may activate the short circuit circuitry 49B to apply a short circuit over the respective winding 19N when the voltage over the load capacitor (CL) 44 is over a predefined value VSCB.

[0115] Rectifier circuitry 5 IN may be connected over filter circuitry 55N and short circuit circuitry 49N to input terminals 23N. As a non-limiting example, rectifier circuitry 5 IN may include a full bridge rectifier including diodes 63N. As another non-limiting example, rectifier circuitry 5 IN may include a half bridge rectifier, for example, when the pair of MOSFET transistors of short circuit circuitry 49N which include their own diodes (intrinsic diode ) considered to be part of rectifier circuitry 5 IN. Rectifier circuitry 5 IN may charge internal capacitor (CIN) 52N.

[0116] As shown in Fig. 8, input of the second, enabling, control circuit (ENn) 54N may be connected over internal capacitor (CIN) 52N and the output of the second, enabling, control circuit (ENn) 54N may be connected to a control terminal of DC-to-DC converter 53N.

[0117] The input circuitry of the second, enabling, control circuit (ENn) 54N may include a voltage divider electrically coupled to the internal capacitor (CIN) 52N for measuring the voltage VCIN over internal capacitor (CIN) 52N. The voltage divider may include a third resistor 64N connected between the first input terminal of an operational amplifier 65N and internal capacitor (CIN) 52N, and a fourth resistor 66N connected between the first input terminal of the operational amplifier 57 and ground (or common).

[0118] Control circuit (ENn) 54N may include, as a non-limiting example, an operational amplifier 65N, which may have one input connected between third resistor 64N and fourth resistor 66N (designated as point 67N), and a second input connected to a stable voltage source 68N. The output of operational amplifier 65N may be connected to a control terminal of DC-to-DC converter 53N. Any of the third and fourth resistor may be a variable resistor (potentiometer) for tuning the threshold voltage VEN, which may activate DC-to-DC converter 53N to convert the voltage of internal capacitor (CIN) 52N into the voltage charging load capacitor (CL) 44. The DC-to-DC converter threshold (activating) voltage may be different for each of the power supply modules 18A to 18N. It is appreciated that resistor 66N may be a variable resistor that may be used to set the voltage level such as VCIN-HIGH, while resistor 69N may be used to set the hysteresis level, or difference, between VCIN-HIGH and VCIN-LOW.

[0119] A power input of DC-to-DC converter 53N may be connected over internal capacitor (CIN) 52N. A control terminal of DC-to-DC converter 53N may be connected to the output of operational amplifier 65N. A feedback terminal of DC-to-DC converter 53N may be connected to point 6 IN, and a reference terminal of DC-to-DC converter 53N may be connected to a stable voltage source 70N, which may be connected to ground via stable voltage source 58N. Each of the DC-to-DC converters 53B to 53N may be controlled to charge load capacitor (CL) 44 to a different voltage VCLB to VCLN respectively.

[0120] Reference is now made to Fig. 9, which is a simplified diagram of relationships between the power supply modules 18 in terms of power output to load capacitor 44, according to one exemplary embodiment.

[0121] As an option, the simplified diagram of Fig. 9 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified diagram of Fig. 9 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0122] Fig. 9 shows how power supply modules 18A, 18B, 18C, and 18N, of harvesting power supply 13 operate as a function of increasing current via their mutual magnetic core 20. It is appreciated that the arrow 71 indicating the increasing current 15 through the electric cable 11 that provides power to the harvesting power supply 13 is presented for graphical purposes only and therefore lacks any scale.

[0123] Fig. 9 also shows the voltage produced by power supply modules 18 A, 18B, 18C, and 18N as curved lines that are curved for graphical purposes only.

[0124] It is appreciated that harvesting power supply 13 employs four power supply modules 18 A, 18B, 18C, and 18N as a non-limiting example, and any number of power supply modules 18 is contemplated. Particularly, harvesting power supply 13 may employ a single power supply module 18 of type A (as shown and described with reference to Fig. 6 and Fig. 7) and any number of power supply module 18 of type N (as shown and described with reference to Fig. 5 and Fig. 8). As a non-limiting example, the harvesting power supply 13 of Fig. 9 may use three power supply modules 18 of type N designated as 18B, 18C, and 18N.

[0125] Fig. 9 also shows the voltage values of VCTRLA to VCTRLN to which power supply modules 18A to 18N may each charge load capacitor (CL) 44, respectively. These voltage values trigger the first control circuits 50A to 50N, respectively, which trigger the respective short circuits 49 on respective terminals 23.

[0126] Fig. 9 also shows, on a different scale Vci, the voltages VCIB to VCIN on respective internal capacitor 52B to 52N, which respectively trigger the second, enabling, control circuit 54B to 54N to activate the respective DC-to-DC converters 53B to 53N.

[0127] It is appreciated that the visual distances between the lines of Fig. 9 indicating voltage values, such as VCLA to VCLN and VCTRLA to VCTRLN reflect general relationships (e.g., greater than), but do not reflect any accurate voltage value or value difference. Similarly, the visual distances between the lines of Fig. 9 indicating voltage values of VCIB to VCIN reflect general relationships (e.g., greater than), but do not reflect any accurate voltage value or value difference.

[0128] When the current 15 through cable 11 (shown in Fig. IB) increases from zero (or another low current value) all the DC-to-DC converters 53 are not operating as the voltage Vci over the respective capacitors 52 (Fig. 5) is too low to trigger the respective second, enabling, control circuits 54 to activate the respective DC-to-DC converters 53. Therefore only power supply module 18A is operating and charging load capacitor (CL) 44 (Fig. 4). Particularly, power supply module 18A charges load capacitor (CL) 44 to an operating voltage, which enables the operation of the operational amplifiers 57 and 65 as well as DC- to-DC converters 53.

[0129] When the current 15 through cable 11 increases further, the charge time of capacitors 52 (shown in Fig. 5) may decrease. Eventually the voltage on capacitor 52N may reach the value of VCIN-HIGH triggering the second, enabling, control circuit 54N to activate DC-to-DC converter 53N. Capacitor 52N may be charged to a higher voltage relative to capacitor 52B and capacitor 52C because the number of windings 19N is larger than the number of windings 19B and 19C (see Fig. 4).

[0130] The DC-to-DC converter 53N may begin to charge load capacitor (CL) 44 and when the voltage on point 6 IN (of the voltage divider 59N-60N) increases over reference voltage 58N the amplifier 57N may activate short circuit circuitry 49N to connect terminals 23N and stop charging internal capacitor (CIN) 52N.

[0131] At this point, capacitor 52N may begin to dicharge through the DC-to-DC converter 53N to load capacitor 44. When the voltage on point 67N (of voltage divider 64N-66N) decreases below reference voltage 68N (VCIN-LOW), the control amplifier 65N may disable the DC-to-DC converter 53N.

[0132] Thereafter, when the load may discharge load capacitor 44 so that the voltage over load capacitor 44 may decrease below the voltage of stable voltage source 58N, operational amplifier 57N may deactivate short circuit circuitry 49N so that the short circuit on terminals 23N is removed and the charging of internal capacitor 52N may resume.

[0133] The duty cycle of the charge and discharge cycle of the internal capacitor 52N may depend on the magnitude of the current 15 through the cable 11 and on the magnitude of the load on load capacitor (CL) 44.

[0134] As current 15 increases the charge time of the 52N capacitor becames so short that windings 19N may be short circuited nearly all the time. Concurrently, the voltage on capacitor 52C increases to the value VCIC-HIGH triggering the second, enabling, control circuit 54C to activate DC-to-DC converter 53C. When the current 15 through cable 11 (Fig. IB) increases further, power supply module 18C replaces power supply module 18N charging load capacitor (CL) 44. Eventually, power supply module 18C may charge load capacitor (CL) 44 to VCTRLN at which power supply module 18N may activate short circuit circuitry 49N to apply short circuit on terminals 23N (and windings 19N) permanently.

[0135] It is appreciated that the short circuit circuitry 49N may protect the electric circuitry of power supply module 18N against the increasing current 15. It is also appreciated that the relatively large number of winding being shortened imply that shortening windings 19N may have a relatively smallest effect on the current through the other windings 19.

[0136] The above operation may repeat for all power supply modules from 18N to 18B. For example, when the current 15 through cable 11 further increases, the voltage on capacitor 52C may increase to the value VCIB-HIGH triggering the second, enabling, control circuit 54C to activate DC-to-DC converter 53C. Power supply module 18C may then replace power supply module 18N charging load capacitor (CL) 44. Power supply module 18C may then charge load capacitor (CL) 44 to VCTRLC at which power supply module 18C may activate short circuit circuitry 49C to apply short circuit on terminals 23 C (and windings 19C).

[0137] Eventually, power supply module 18B may charge load capacitor (CL) 44 to VCTRLB at which power supply module 18B may activate short circuit circuitry 49B to apply short circuit on terminals 23B (and windings 19B). At this point the operation returns to power supply module 18A because all the windings 19B to 19N are now shortened by respective short circuit circuitry 49B to 49N.

[0138] Due to the very high current 15, power supply module 18 A may charge load capacitor (CL) 44 to VCTRLA at which power supply module 18A may activate short circuit circuitry 49A to apply short circuit on terminals 23 A (and windings 19A). At this point power supply module 18A (and harvesting power supply 13) enters pulse width modulation (PWM) mode 72, as explained below with reference to Figs 10A to 10D.

[0139] When power supply module 18N is operating in pulse width modulation (PWM) mode and the current 15 through cable 11 (Fig. IB) decreases, the load 46 (Fig. 4) discharges load capacitor (CL) 44 to voltage VCLA below the short circuit activation voltage and power supply module 18A exits the pulse width modulation (PWM) mode.

[0140] It is therefore appreciated that the power supply module 18 having the largest number of turns (loops) of winding 19 is set to charge load capacitor 44 to the lowest voltage, and each power supply module 18 having a smaller number of turns (loops) of winding 19 is set to charge load capacitor 44 to a higher voltage.

[0141] Returning to Fig. 4, and in view of Figs. 5 to 8, it is appreciated that power harvesting power supply 13 may first activate power supply module 18A to charge load capacitor (CL) 44 to VCLA. VCLA, may be high enough to power the components of power supply modules 18B to 18N such as the operational amplifiers 57 and 65 and the DC-to-DC converter 53.

[0142] While power supply module 18A may charge load capacitor (CL) 44 (and before VCLA is reached) power supply modules 18B to 18N may start charging their respective internal capacitors (CIN) 52B to 52N. When the voltage VCIN over any of internal capacitors (CIN) 52B to 52N reaches the respective threshold (VCIN-HIGH) value the second, enabling, control circuit (ENn) 54N may activate the respective DC-to-DC converter 53N-53B to convert the voltage of the respective internal capacitor and charge load capacitor (CL) 44 up to the respective VCLNIO VCLB. It is appreciated that for power supply modules 18B to 18N, the respective DC-to- DC converter 53 may still charge load capacitor (CL) 44 (from the respective internal capacitor (CIN) 52) even when the short circuit is applied over the respective input contacts 23, until the voltage over the respective internal capacitor (CIN) 52 falls below the respective threshold (VCIN-LOW) value, and the respective second, enabling, control circuit (ENn) 54 stops the respective DC-to-DC converter 53.

[0143] If the current via the electric cable 11 falls so that power supply module 18B cannot charge of load capacitor (CL) 44 to VCLB. then power supply module 18A may charge load capacitor (CL) 44 to VCLA while all power supply modules 18B to 18N are disabled.

[0144] When power supply module 18A is operating as the main power supply module 18 charging load capacitor (CL) 44, this main power supply module 18A may operate in pulse width modulation mode (PWM). As a non-limiting example, when power supply module 18A operates as the main power supply module 18 the width of the charging pulse is the time in which the short circuit circuitry (SCA) applies a short circuit between input contacts 23 A.

[0145] The time, or length, of the pulse charging the load capacitor (CL) 44 may change according to the value of the current via electric cable 11, and / or according to the load applied to output contancts terminals 45, and / or according to the maximum output current of the DC-to-DC converter (when any of power supply modules 18B to 18N is operating as the main power supply module 18).

[0146] The time, or length, of the pulse charging the load capacitor (CL) 44, particularly for power supply module 18 A, may be much shorter than the sine wave of the alternating current flowing via electric cable 11 (namely, much less than 20 miliseconds for a 50Hz AC current).

[0147] Reference is now made to:

[0148] Fig. 10A, which is a simplified diagram of the current IWA through winding 19A, current IWB through winding 19B, and current IWN through winding 19N, according to one exemplary embodiment,

[0149] Fig. 10B, which is a simplified diagram of pulse width modulated current IRECA via rectifier circuitry 51 A charging the load capacitor (CL) 44, according to one exemplary embodiment, Fig. IOC, which is a simplified diagram of the voltage activating the short circuit circuitry 49 A to apply a short circuit over the respective winding 19 A, according to one exemplary embodiment, and

[0150] Fig. 10D, which is a simplified diagram of the voltage on load capacitor (CL) 44, according to one exemplary embodiment.

[0151] As an option, the simplified diagrams of Fig. 10A, Fig. 10B, Fig. IOC, and Fig. 10D may be viewed in the context of the details of the previous Figures. Of course, however, the simplified diagrams of Fig. 10A, Fig. 10B, Fig. IOC, and Fig. 10D may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0152] In the non-limiting example of pulse width modulated charging of load capacitor (CL) by power supply module 18 A, as shown in Fig. 10A, Fig. 10B, Fig. IOC, and Fig. 10D the discharge current through the load 46 (Fig. 4) is substantially constant, at least within a cycle of the IWA AC current. Therefore, the discharge periods of load capacitor (CL) designated by numerals 73 are substantially similar. However, as the charging periods of load capacitor (CL) designated by numerals 74, vary in accordance with the value of IWA, where a higher IWA produces a shorter charging period.

[0153] Reference is now made to Fig. 11, which is a simplified diagram of relationships between the power supply modules 18 in terms of power output to load capacitor 44, when current 15 is decreasing, according to one exemplary embodiment.

[0154] As an option, the simplified diagram of Fig. 11 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified diagram of Fig. 11 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0155] Fig. 11 shows how power supply modules 18A, 18B, 18C, and 18N, of harvesting power supply 13 operate as a function of decreasing current 15 via their mutual magnetic core 20. It is appreciated that the arrow 75 indicating the decreasing current 15 through the electric cable 11 that provides power to the harvesting power supply 13 is presented for graphical purposes only and therefore lacks any scale. Fig. 11 also shows the voltage produced by power supply modules 18 A, 18B, 18C, and 18N as curved lines that are curved for graphical purposes only.

[0156] As shown in Fig. 11, when current 15 decreases, power supply module 18A may fail to charge load capacitor (CL) 44 to voltage VCTRLB that controls the first control circuit (CTRLB) 50B. Therefore, deactivating short circuit circuitry 49B, thus removing the short circuit over the respective winding 19B. At this point power supply modules 18B may resume operation charging load capacitor (CL) 44. Power supply module 18A may now stop charging load capacitor (CL) 44 because its input voltage in winding 19A is lower than the voltage applied by power supply module 18B on load capacitor (CL) 44.

[0157] As shown in Fig. 11, when current 15 further decreases, power supply module 18B may fail to charge load capacitor (CL) 44 to voltage VCTRLC that controls the first control circuit (CTRLC) 50C. Therefore, deactivating the short circuit circuitry 49C, thus removing the short circuit over the respective winding 19C. At this point power supply modules 18C may resume operation charging load capacitor (CL) 44.

[0158] As shown in Fig. 11, when current 15 further decreases, power supply module 18C may fail to charge load capacitor (CL) 44 to voltage VCTRLN that activates the first control circuit (CTRLN) 5 ON. Therefore, deactivating the short circuit circuitry 49C, thus removing the short circuit over the respective winding 19N. At this point power supply modules 18N may resume operation charging load capacitor (CL) 44.

[0159] When current 15 further decreases, power supply module 18N may fail to charge load capacitor (CL) 44 to voltage less then VCLN SO that power supply modules 18A may resume operation charging load capacitor (CL) 44.

[0160] It is appreciated that the non-limiting example as shown and described with reference to Fig. 4 to Fig. 8 is implemented using analog circuitry, which may be replaced, in whole or in part, by any form of digital circuitry, which may reproduce the same logic described above with reference to Fig. 9 to Fig. 11. Such digital circuitry, alternatively or additionally, may be embodies using one or more processors, or one or more digital signal processors (DSP), one or more field programmable gate arrays (FPGA), which may reproduce the logic described above, for example, using computer code and. or software program. Reference is now made to Fig. 12, which is a simplified diagram of relationships between the voltage on internal capacitors (CIN) 52 and the voltage on load capacitor 44, as the current 15 through cable 11 increases, according to one exemplary embodiment.

[0161] As an option, the simplified diagram of Fig. 12 may be viewed in the context of the details of the previous Figures. Of course, however, the simplified diagram of Fig. 12 may be viewed in the context of any desired environment. Further, the aforementioned definitions may equally apply to the description below.

[0162] Particularly, Fig. 12 shows that the voltage value on internal capacitors (CIN) 52 VCIN- HIGH is larger than VCIN-LOW that is larger than VCIC-HIGH that is larger than VCIC-LOW that is larger than VCIB-HIGH that is larger than VCIB-LOW.

[0163] It is appreciated that optionally each DC-to-DC converter 53 is tuned to charge load capacitor (CL) 44 to a slightly different voltage. For example, DC-to-DC converter 53B may charge load capacitor (CL) 44 to VCLB, DC-to-DC converter 53C may charge load capacitor (CL) 44 to VCLC, and DC-to-DC converter 53N may charge load capacitor (CL) 44 to VCLN, where VCLB >VCLC >VCLN.

[0164] Therefore as shown in Fig. 12, when DC-to-DC converter 53N charges load capacitor (CL) 44 to VCLC >VCLN, DC-to-DC converter 53N may stop charging load capacitor (CL) 44 because the voltage on load capacitor (CL) 44 is already higher than its output voltage. Similarly, when DC-to-DC converter 53B charges load capacitor (CL) 44 to VCLB >VCLC, DC-to-DC converter 53C may stop charging load capacitor (CL) 44 because the voltage on load capacitor (CL) 44 is already higher than its output voltage.

[0165] Returning to Fig. 8, it may be seen that operational amplifier 57N has an input reference voltage in the form of stable voltage source 58N. Operational amplifier 57N is therefore activated (to activate short circuit circuitry 49N) when the voltage on point 6 IN is higher than the reference voltage.

[0166] It may be seen that DC-to-DC converter 53N has an output reference voltage in the form of stable voltage source 70N. This reference voltage sets the output voltage of DC-to- DC converter 53N. Stable voltage source 70N is connected is series with stable voltage source 58N so that the output voltage of DC-to-DC converter 53N is always higher than the reference voltage of operational amplifier 57N. Therefore, synchronizing DC-to-DC converter 53N, and first control circuit (CTRLn) 50N) to eliminate the latching of the two circuits.

[0167] Furthermore, it is appreciated that when DC-to-DC converter 53N charges load capacitor 44 to voltage that is high enough to activate the short circuit over terminals 23N, power supply modules 18N (type N) may enter pulse width modulation mode 76 (Fig. 12).

[0168] Returning to Fig. 12, the pulse width modulation mode 76 may be seen for power supply module 18N, power supply module 18C, and power supply module 18B.

[0169] It is appreciated that certain features, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0170] Although descriptions have been provided above in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation, or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art.

Claims

CLAIMSWhat is claimed is:

1. A power supply comprising: a ferromagnetic core configured to receive therewithin an electric cable of an electric grid the electric cable carrying an electric current I; an output condenser Cout configured to be electrically coupled to an electric load; a first power supply module PSA comprising: a secondary winding WA, wound on the ferromagnetic core; a rectifier part having an input and an output, wherein the input is electrically coupled to the secondary winding WA, and wherein the output is electrically coupled to the output condenser Cout; and a short circuit circuitry having an input and an output, wherein the input is electrically coupled to the output condenser Cout, and wherein the output is electrically coupled to the secondary winding WA and is operative to apply a short circuit on the secondary winding WA. a second power supply module PSN comprising: a secondary winding WN, wound on the same ferromagnetic core; a rectifier part having an input and an output, wherein the input is electrically coupled to the secondary winding WN, and wherein the output is electrically coupled to an internal capacitor Ci. a DC-to-DC converter circuit having an input and an output, wherein the input is electrically coupled to the internal capacitor Ci, and wherein the output is electrically coupled to the same output condenser Cout; an enabling control circuit having an input and an output, wherein the input is electrically coupled to the capacitor Ci, and wherein the output is electrically coupled to the control terminal of the DC-to-DC converter circuit; and a short circuit circuitry having an input and an output, wherein the input is electrically coupled to the same output condenser Cout, and wherein the output is electrically coupled to the secondary winding WN and is operative to apply a short circuit on the secondary winding WN.

2. The power supply according to claim 1, additionally comprising at least one of: winding WN comprises more windings than winding WA; the second power supply module PSN comprises a plurality of second power supply modules PSi to PSN, each having a respective winding Wi to WN wound on the same ferromagnetic core, and wherein the winding WN has more windings than the winding WN- i, and the winding Wi has more windings than the winding WA; wherein each of the power supply modules PSi to PSN is configured to operate in a different current operating range of the electric current I; and wherein a short circuit is applied to the secondary windings WN of each of the respective rectifier part if the electric current I is higher than the respective current operating range.

3. The power supply according to claim 1, additionally comprising: wherein power supply module PSA is operative to work in pulse-width-modulation mode comprising two states, a charging state, and a discharging state; and wherein in the discharging state the short circuit circuitry applies a short circuit on the secondary winding WA.

4. The power supply according to claim 2, additionally comprising: wherein the power supply module PSA is operative to work in pulse-width- modulation mode when all power supply modules PSN have their respective short circuit circuitry applying a short circuit on their secondary windings WN respectively.

5. The power supply according to claim 2, additionally comprising: wherein the enabling control circuits of power supply modules PSN are operative to activate their respective DC-to-DC converter circuits when voltage on respective internal capacitor CIN is VCIN-HIGH and deactivate the respective DC-to-DC converter circuit when voltage on respective internal capacitor CIN is VCIN-LOW, wherein VCIN-HIGH is larger than VCIN-LOW; and wherein VCIN-LOW of power supply module PSN is larger than VCIN-HIGH of power supply module PSN-I.

6. The power supply according to claim 2, additionally comprising: wherein DC-to-DC converter circuit of power supply module PSN-I is operative to provide output voltage that is higher than output voltage of DC-to-DC converter circuit of power supply module PSN.

7. The power supply according to claim 2, additionally comprising: wherein setting of output voltage of DC-to-DC voltage converter circuit is associated with setting of trigger voltage of a first control circuit activating the short circuit circuitry, to synchronize the operation of the circuits.

8. A method for extracting power from electromagnetic field surrounding an electric cable of an electric grid, the method comprising: providing a ferromagnetic core substantially surrounding the electric cable, wherein the electric cable carrying an electric current I; providing an output condenser Cout configured to be electrically coupled to an electric load; providing a first power supply module PSA comprising: a secondary winding WA, wound on the ferromagnetic core; a rectifier part having an input and an output, wherein the input is electrically coupled to the secondary winding WA, and wherein the output is electrically coupled to the output condenser Cout; and a short circuit circuitry having an input and an output, wherein the input is electrically coupled to the output condenser Cout, and wherein the output is electrically coupled to the secondary winding WA and is operative to apply a short circuit on the secondary winding WA.Providing a second power supply module PSN comprising: a secondary winding WN, wound on the same ferromagnetic core; a rectifier part having an input and an output, wherein the input is electrically coupled to the secondary winding WN, and wherein the output is electrically coupled to an internal capacitor Ci.A DC-to-DC converter circuit having an input and an output, wherein the input is electrically coupled to the internal capacitor Ci, and wherein the output is electrically coupled to the same output condenser Cout; an enabling control circuit having an input and an output, wherein the input is electrically coupled to the capacitor Ci, and wherein the output is electrically coupled to the control terminal of the DC-to-DC converter circuit; and a short circuit circuitry having an input and an output, wherein the input is electrically coupled to the same output condenser Cout, and wherein the output is electrically coupled to the secondary winding WN and is operative to apply a short circuit on the secondary winding WN.

9. The method of claim 8, additionally comprising at least one of: wherein winding WN comprises more windings than winding WA; wherein the second power supply module PSN comprises a plurality of second power supply modules PSi to PSN, each having a respective winding Wi to WN wound on the same ferromagnetic core, and wherein the winding WN has more windings than the winding WN- i, and the winding Wi has more windings than the winding WA; wherein each of the power supply modules PSi to PSN is configured to operate in a different current operating range of the electric current I; and wherein a short circuit is applied to the secondary windings WN of each of the respective rectifier part if the electric current I is higher than the respective current operating range.

10. The method of claim 8, additionally comprising: wherein power supply module PSA is operative to work in pulse-width-modulation mode comprising two states, a charging state, and a discharging state; and wherein in the discharging state the short circuit circuitry applies a short circuit on the secondary winding WA.

11. The method of claim 9, additionally comprising: wherein the power supply module PSA is operative to work in pulse-width- modulation mode when all power supply modules PSN have their respective short circuit circuitry applying a short circuit on their secondary windings WN respectively.

12. The method of claim 8, additionally comprising: wherein the enabling control circuits of power supply modules PSN are operative to activate their respective DC-to-DC converter circuits when voltage on respective internal capacitor CIN is VCIN-HIGH and deactivate the respective DC-to-DC converter circuit when voltage on respective internal capacitor CIN is VCIN-LOW, wherein VCIN-HIGH is larger than VCIN-LOW; and wherein VCIN-LOW of power supply module PSN-I is larger than VCIN-HIGH of power supply module PSN.

13. The method of claim 8, additionally comprising: wherein DC-to-DC converter circuit of power supply module PSN-I is operative to provide output voltage that is higher than output voltage of DC-to-DC converter circuit of power supply module PSN.

14. The method of claim 8, additionally comprising: associating setting of output voltage of DC-to-DC voltage converter circuit with setting of trigger voltage of a first control circuit activating the short circuit circuitry, to synchronize the operation of the circuits.

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