Efficiency monitor for inductive power transmission

Abstract

An efficiency monitor (4300, 5300) for monitoring the efficiency of an inductive power transmission between an inductive power socket (4210, 5210) and an electrical device (290, 4290, 5290), the inductive power socket (4210, 5210) comprising at least one primary coil (4220, 5220) connected to an electrical power supply, for inductive coupling with a secondary coil (4260, 5260) of the electrical device (290, 4290, 5290) that is connected to an electrical load (4280, 5280), the efficiency monitor (4300, 5300) comprising: at least one processor (4162, 5162) incorporated in the inductive power socket (4210, 5210); and at least one input power monitor (4122, 5122), incorporated in the inductive power socket (4210, 5210), and configured to measure an input power (Pin) supplied to the primary coil (4220, 5220) and to provide the processor (4162) with an input power value obtained by measuring said input power; and characterized by at least one output energy monitor (4124, 5124), incorporated in the electrical device (290, 4290, 5290) and configured to measure an output energy (Pout) received by the secondary coil (4260, 5260) and communicate an output energy value obtained by measuring said output energy to the processor (4162); where said at least one processor (4162) is configured to determine a power loss index based on at least one of: an efficiency ratio Q, defined as the ratio of said output energy to said input energy; and an efficiency differential Δ, defined as the difference between said output energy and said input energy.

Description

Efficiency monitor for inductive power transmission The present invention relates to a system and method for monitoring efficiency and controlling energy transfer through an inductive power coupling. More specifically, the invention relates to an efficiency monitor according to claim 1, and to an inductive power socket according to claim 9. Furthermore, the invention relates to an electrical device and a method of using said efficiency monitor. A monitor according to the preamble portion of claim 1, known from GB 2414 121 A, describing an energy measurement assembly in the primary assembly. The energy measurement unit measures the energy drawn by the secondary devices from the primary assembly. A control assembly then determines, based on the measured energy and the sum of the load measurements received from the secondary devices, whether the power supply to the secondary devices should be restricted or stopped. For safety, the power supply side of a conductive pair is generally the female part, and it has no bare conductive elements protruding from it. A male connector attached to the device is the corresponding male part with bare pins. The size of the pins and holes is such that a child cannot insert their fingers into them. High-quality female connectors provide a grounding connection, and only when a male connector with a longer grounding pin is inserted is it possible to insert a pin (or anything else) into the holes connected to the live and neutral wires that carry the current. However, the holes in female connectors are dangerous, and children sometimes manage to insert pencils, pins, and other objects into them, sometimes with fatal results. Water can also cause a short circuit and lead to electrocution. Therefore, it can be safer and more reliable to provide power outlets without female connectors, such as inductive couplers. Inductive power coupling allows power to be transferred from a power supply to an electrical load without connecting wires. A power supply is connected to a primary coil, and an oscillating electrical potential is applied across the primary coil, inducing an oscillating magnetic field around it. This oscillating magnetic field can induce an oscillating electric current in a secondary coil placed near the primary coil. In this way, electrical power can be transmitted from the primary coil to the secondary coil by electromagnetic induction without the two coils being conductively connected. When electrical power is transferred inductively from a primary coil to a secondary coil, the pair is said to be inductively coupled.An electrical load connected in series with this secondary coil can draw energy from the power source when the secondary coil is inductively coupled to the primary coil. Low-power inductive electrical energy transmission systems over extended surfaces are not new. An example of this type is described in Hui's US patent 7,164,255 B1. In Hui's system, a flat inductive battery charging system is designed to allow electronic devices to be recharged. The system includes A flat charging module has a charging surface on which a device to be recharged is placed. Within the charging module, and parallel to the charging surface, at least one, and preferably a set of primary windings, is provided. These inductively couple power to a secondary winding formed in the device to be recharged. Such systems are suitable for charging batteries, as they typically provide relatively low-power inductive coupling. However, it will be appreciated that extended base units, such as the Hui charging surface, which transmit power continuously and approximately uniformly across the entire area of ​​the assembly, are not suitable for use with high-power systems. Because they don't require holes for mating pins, sockets without female connectors can be concealed more effectively than conductive female connectors and are therefore less conspicuous. A primary inductive coil, for example, can be hidden behind a surface. Generally, the fact that sockets without female connectors are less conspicuous is advantageous. However, being harder to detect than conventional power sockets has its drawbacks. The user must somehow locate the socket before being able to use it by placing a secondary coil in close proximity to it. The problem of locating such female connectors is particularly acute when the power sockets are behind a concealing surface such as a desktop or wall, and their positions can be adjusted over a large area.The location of "hot spots" or female connectors for mobile power supplies is particularly problematic in high-power systems where an extended power transmission surface is not provided. Furthermore, a high-power primary coil produces a large, oscillating magnetic field. When a secondary coil is inductively coupled to the primary coil, the resulting magnetic flux linkage causes energy to be drawn into the secondary coil. When there is no secondary coil to concentrate the energy, the oscillating magnetic field causes high-energy electromagnetic waves to be transmitted, which can be harmful to bystanders. Unlike low-power systems, such as the Hui charging surface, where excess heat can be easily dissipated, decoupled high-power primary coils and their surroundings can become dangerously hot. In order to efficiently power electrical devices, it is important that certain power parameters are regulated. By providing feedback on parameters such as voltage, current, operating temperature, and the like, the power supply to an electrical device can be optimized to minimize energy losses and prevent overheating of components. Consequently, it can be useful to provide a signal transfer channel for power regulation and related functions. Therefore, a communication channel between the power source and the load device is often provided alongside the power input channel in conventional conductive power supply systems.The procedures for providing such a communication channel include wired connections to the device that are often packaged in the same cable as the electric power lines and conductively coupled to the load through conventional plug-and-pin connectors. Leakage prevention systems have been considered that can detect energy emanating from the primary coil of an inductive power source and cut off power to the primary coil if no secondary coil is connected. However, to prevent energy leakage from a primary coil while a secondary coil is connected, a communication channel between the primary and secondary coils would be useful. However, due to the lack of connecting wires in inductive power couplings, conductive communication channels are impractical. There is a need for an alternative control system for inductive power outlets, capable of regulating the energy transfer from the outlet to a secondary coil coupled to it. The present invention addresses this need. This technical problem is solved by an efficiency monitor according to claim 1, by an electrical device according to claim 7, by an inductive power supply according to claim 9, and by a method according to claim 11. Advantageous embodiments are indicated in the additional claims. For a better understanding of the invention and to show how it can be implemented, reference will now be made, merely by way of example, to the accompanying drawings. With specific reference now to the detailed drawings, it is emphasized that the details shown are by way of example and for the purpose of illustrative discussion of preferred embodiments of the present invention only, and are presented with the aim of providing what is believed to be the most useful and readily understandable description of the principles and conceptual aspects of the invention. In this respect, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention; the description provided with the drawings shows those skilled in the art how various forms of the invention can be implemented in practice. In the accompanying drawings: Fig. 1 is a block diagram showing the main elements of an inductive power coupling incorporating a signal transfer system according to a first embodiment of the invention; Fig. 2a-d shows another embodiment of the signal transfer system in which a control signal is transmitted through an inductive power coupling; Fig. 3 is a schematic diagram showing a signal transfer system integrated into a contactless inductive power coupling system for powering a computer; Fig. 4 is a flowchart showing a procedure for transferring a transmission signal through an inductive power coupling according to the invention. Fig. 5 is a block diagram representing another embodiment of the signal transfer system incorporated in an efficiency monitor to monitor the efficiency of power transmission by means of an inductive power take-up; Fig. 6a is a schematic diagram of an inductive power outlet with an electrical load inductively coupled to it, monitored by an efficiency monitor; Fig. 6b is a schematic diagram of the inductive power take-up of Fig. 6a where a power draw has been introduced between the primary and secondary coils; Fig. 7 is a flowchart of a procedure for using the signal transfer system to monitor the efficiency of power transmission by means of an inductive power take-off; Fig. 8a is a schematic representation of another signal transfer system incorporated in a power socket locator used to indicate the location of an inductive power socket concealed behind a surface, which, however, is not part of the claimed invention; Fig. 8b is a schematic representation of a computer located on the surface of Fig. 8a and powered by the hidden primary socket; Fig. 9 is a block diagram representing the main features of the power outlet locator; Fig. 10 is a schematic representation of a power outlet locator with four sensors; Fig. 11 is a block diagram depicting a power socket locator configured to receive and decode a control signal transmitted by a power socket using yet another signal transfer system, which, however, is not part of the claimed invention; Figures 12a-c are schematic representations of a mobile phone incorporating a power outlet locator, where a graphical user interface represents a virtual target superimposed on an image of the surface, and Figure 13 is a schematic representation of a signal transfer system incorporated in a system for locating secondary coils placed on a multi-coil power transmission surface. Reference is made to Figure 1, which shows a block diagram of the main elements of an inductive power coupling 200 incorporating a signal transfer system 100 according to a first embodiment of the invention. The inductive power coupling 200 consists of a primary inductive coil 220 and a secondary inductive coil 260. The primary coil 220 is connected to a power supply 240, typically through an exciter 230 that provides the necessary electronics to drive the primary coil 220. The pulse electronics may include a switching assembly that provides a high-frequency oscillating voltage supply, for example. The secondary coil 260 is connected to a load 280. When the secondary coil 260 approaches the primary coil 220, the pair of coils forms an inductive coupling and energy is transferred from the primary coil 220 to the secondary coil 260. In this way, a power outlet 210 can supply power to an electrical device 290. The signal transfer system 100 comprises: a signal generator 120, for generating a control signal Sc; a transmitter 140 for transmitting said control signal Sc; and a receiver 160 for receiving said control signal Sc. Although in the signal transfer system 100 described in this invention, the transmitter 140 is incorporated into the power socket 210 and the receiver 160 is incorporated into the electrical device 290, it will be appreciated that a transmitter 140 can be incorporated alternatively or additionally into the electrical device 290 and a receiver 160 can be incorporated alternatively or additionally into the power socket 210. The Sc control signal communicates coded data related to power transmission. This data may be relevant for regulating efficient power transmission. Examples of such data include parameters such as: voltage, current, temperature, or operating power required for electrical load 280; the measured voltage, current, temperature, or power supplied to electrical load 280 during operation; the measured voltage, current, temperature, or power received by electrical load 280 during operation; and similar parameters. In other embodiments, the control signal Sc can communicate data related to the coordinates of the primary inductive coil 220 in order to indicate the location of the power outlet 210. Alternatively, the control signal Sc can communicate data related to the identity or presence of the electrical load 280, such as the location of the secondary coil 260, or an identification code for the electrical device 290 or its user. Multiple transmitters 140 and receivers 160 can be used with the signal transfer system. When the primary and secondary coils 220 and 260 are galvanically isolated, for example, optocouplers can have a light-emitting diode acting as a transmitter 140, sending optically encoded signals over short distances to a phototransistor acting as a receiver 160. Typically, the optocouplers must be aligned so that there is a line of sight between the transmitter and receiver. In systems where alignment between the transmitter 140 and receiver 160 may be problematic, optocoupling may be unsuitable, and alternative systems such as ultrasonic signals transmitted by piezoelectric elements or radio signals such as Bluetooth, Wi-Fi, and similar technologies may be preferred. Alternatively, the primary and secondary coils 220 and 260 can serve as both the transmitter 140 and the receiver 160. Coil-to-coil signal transfer One aspect of the present embodiments relates to a signal transfer system for transferring a transmission signal with respect to an electrical load that can be connected by inductive power coupling to a power source.The inductive power coupling comprises a primary coil connectable to the power source in inductive alignment with a secondary coil connectable to the electrical load; the system comprises at least one auxiliary load; at least one switching assembly comprising a modulator for modulating a bit rate signal with an input signal to create a modulated signal and a switch for intermittently connecting the auxiliary load to the secondary coil according to the modulated signal; at least one current monitor for monitoring the primary current drawn by the primary coil and producing a primary current signal; and at least one correlator for cross-correlating the primary current signal with the bit rate signal to produce an output signal. The switching assembly also preferably includes a controller configured to encode data into the input signal. Typically, the switching assembly further includes a frequency divider, and inductive power coupling transfers power at a drive frequency, with the bit rate frequency being an integer fraction of the drive frequency. Inductive power coupling is typically a device where the primary coil is galvanically isolated from the secondary coil. The device may include, for example, a transformer, a DC-DC converter, an AC-DC converter, an AC-AC converter, a reverse transfer transformer, a reverse transfer converter, a full-bridge converter, a half-bridge converter, a buck converter, a boost converter, a buck-boost converter, a SEPIC converter, or a zeta converter.Optionally, the input signal carries coded data related to, for example, the presence of the electrical load, the operating voltage required for the electrical load, the operating current required for the electrical load, the operating temperature required for the electrical load, the operating voltage measured for the electrical load, the operating current measured for the electrical load, the operating temperature measured for the electrical load, and / or a user identification code. In one embodiment, a contactless inductive coupling is provided, comprising the signal transfer system where the primary coil is embedded in a female power socket and the secondary coil is embedded in a male power connector galvanically isolated from the female power socket. One aspect of the technology described in this invention teaches a method for transferring a signal through an inductive power coupling, where the inductive power coupling comprises a primary coil connected to a power source and a secondary coil connected to an electrical load, the method comprising the following steps: providing an input signal, providing a bit rate signal, modulating the bit rate signal with the input signal to create a modulated signal, connecting an auxiliary load to the secondary coil intermittently according to the modulated signal, monitoring a primary current drawn by the primary coil and producing a primary current signal; and cross-correlating the primary current signal with the bit rate signal to generate an output signal. According to another aspect, a procedure is taught for regulating energy transfer through a contactless inductive coupling, where the output signal provides details of the load's energy requirements. Typically, the input signal is provided by encoding data related to at least one energy requirement of the electrical load into the input signal. Optionally, and typically, the energy requirement depends on parameters such as operating voltage, operating current, and / or operating temperature. Alternatively, the input signal is provided by monitoring at least one operating parameter of the electrical load and encoding the monitored parameter data into the input signal. Optionally, the parameter is selected from the group comprising operating voltage, operating current, and operating temperature.Typically, the procedure for transferring a signal through an inductive power coupling includes a preliminary stage of detecting the presence of an electric charge. Reference is made to Figs. 2a-d, which show a signal transfer system 2100 according to a second general embodiment of the invention. With particular reference to Fig. 2a, the signal transfer system 2100 is configured to transmit a transmission signal through an inductive power coupling 2200. The inductive power coupling 2200 consists of a primary coil L1 that can be connected to a power source 2240 and a secondary coil L2, galvanically isolated from it, through which an electrical load 2280 can be connected either directly or through an AC-DC converter 2270. A transmission circuit 2140 can be connected in parallel with the electrical load 2280. The transmission circuit 2140 comprises an auxiliary load 2142 connected to the secondary coil L2 through a switching assembly 2144. Typically, the auxiliary load 2142 is much smaller than the electrical load 2280. A corresponding receiving circuit 2160 is connected to the primary coil L1 of the inductive power coupling 2200 and comprises a current monitor 2162, such as an ammeter in series with the primary coil L1, and a correlator 2164. The switching assembly 2144 is configured to receive an input signal Sin and a bit rate signal Fb. A modulator (not shown) modulates the bit rate signal Fb with the input signal Sin to produce a modulated signal SM. The auxiliary load 2142 is intermittently connected to the secondary coil L2 at a rate determined by the modulated signal Sm. The power source 2240, such as an AC voltage source, intermittent DC voltage source, or the like, is configured and operable to produce a primary voltage V1 oscillating at a driving frequency Fd. The oscillating primary voltage Vi in coil L1 induces a secondary voltage V2(t) in secondary coil L2. The secondary voltage V2(t) is optionally passed through an AC-DC converter 22 that produces a DC voltage V22(t). The electrical load 2280, which is connected to the secondary coil L2—either directly or through the AC-DC converter 227—draws a load current I22. The energy P22 supplied to the load 2280 is given by the dot product of the voltage V22 and the load current I22. When the auxiliary load 2144 is connected, an additional auxiliary current I24 is also drawn. Therefore, with the auxiliary load 2144 connected, the total energy P2 drawn by the secondary coil L2 is given by: where the auxiliary current signal Í24 (t) varies with the modulated signal Sm- The input energy P1(t) supplied to the primary coil L1 is given by: where the primary voltage Vi(t) oscillates at the driving frequency Fd which is determined by the 2240 power supply. The input energy P1(t) supplied by the primary coil L1 is generally proportional to the total energy P22(t) extracted by the secondary coil L2, and the primary voltage Vi(t) is determined by the power supply. The disturbances in the primary current Iio(t) supplied to the primary coil L1 are therefore proportional to i24(t). The current monitor 2162 monitors the primary current Iio(t) over time, producing a primary current signal Sp that typically has characteristics similar to the modulated signal Sm. The correlator 2164 is configured to cross-correlate the primary current signal Sp with the bit rate Fb. Therefore, the output signal Sout of the correlator 2164 has the same characteristics as the input signal Sin. In this way, the information carried by the input signal Sin is transmitted from the transmitter circuit 2140 and is recoverable by the receiver circuit 2160 from the output signal Sout. It should be noted that the signal transfer system 2100 described in this invention transmits a transmission signal through the same inductive power coupling 2200 that is used for power transmission.This differs from prior art transmission systems, which use additional elements to provide separate signal transmission channels from power transmission channels. As a result of this innovative approach, additional transmission elements such as optocouplers, piezoelectric elements, supplementary coil pairs, and the like are generally not required. With reference now to Fig. 2b, an exemplary transmission circuit 2140 of the signal transfer system 2100 of Fig. 2a is shown. An AC-to-DC converter 2270 comprising a diode 2272 and a capacitor 2274, which is connected in parallel to the secondary coil L2, converts an AC secondary voltage V2 from the secondary coil L2 into a DC load voltage V22 which is connected across an electrical load 2280. The connection between the auxiliary load 2142 and the load voltage V2 is controlled by a switching assembly 2144 that includes a frequency divider 2145, a microcontroller 2146, and a switch 2147. The frequency divider 2145 provides the bit rate signal Fb, which is passed to the microcontroller 2146. The microcontroller 2146 is configured to modulate the bit rate signal Fb according to input signals, including control signals Sc from the electrical load 2280 and external signals Se, as described below. Sc control signals can be used to regulate the power supply. Sc control signals typically provide data related to load parameters. These typically include the required operating voltage, current, and temperature, as well as the actual measured operating voltage, current, and temperature as monitored during load operation. External signals can be used to provide the transmitter circuit 2140 with external data that will be digitally encoded into the Sin input signal by the microcontroller 2146 and transmitted to the receiver circuit 2160. The external information can, for example, provide useful supplementary data such as a user identification code, a master key, the battery level of the charging device, and the like. It will be appreciated that the ability to transmit supplementary information such as external signals Se through inductive power coupling 2200 presents an additional advantage over prior art systems that are only suitable for transmitting control signals. Figure 2c shows a schematic representation of an exemplary receiver circuit 2160 according to the signal transfer system of Figure 2a, which consists of a current monitor 2162, a frequency divider 2166, a correlator 2164, and a microcontroller 2168. The frequency divider 2166 provides the bit rate signal Fb, which is typically an integer fraction of the drive frequency Fd. The current monitor 2162 provides a primary current signal Sp, which is passed to the correlator 2164 for cross-correlation with the bit rate signal Fb. The resulting output signal (Sout) is passed to a microcontroller (2168), which can use the output signal (Sout) to pass a control signal Sc to control the power supply (2240) in order to regulate the power supplied to the electrical load (2280). The 2168 microcontroller can also be used to extract external Se signals from the output signal. An exemplary use of the receiver circuit 2160 of Fig. 2c is highlighted in Fig. 2d, which shows the receiver circuit 2160 configured to control a reverse-transfer power source 2240F. In a reverse-transfer converter, a DC voltage source 2242 is intermittently connected to a primary coil L1 by a switch 2244. This produces a variable voltage signal Vi(t) in the primary coil L1, which induces a secondary voltage V2 in a secondary coil L2 (Fig. 2a). The secondary coil L2 is typically connected to a leveling circuit such as the AC-DC converter 2270 shown in Fig. 2b to produce a DC output. The switch 2244 is controlled by an exciter 2248 that receives a pulse signal Fd from a clock 2246. The pulse signal Fd determines the frequency at which the DC voltage source 2242 is connected to the primary coil L1. The power supplied to the primary coil L1 can be regulated by varying the duty cycle of the switch 2244. The duty cycle is the ratio of the time between pulses during which the switch 2244 is closed. Fig. 2d shows the innovative use of the signal transfer system 2100, which receives a feedback signal transferred between the primary and secondary power transmission coils and is received by the receiver circuit 2160. This is an improvement on prior art reverse transfer converters, where additional elements such as optocouplers or the like were used to transmit feedback signals. The 2168 microcontroller generates a control signal Sc that is transmitted to the 2248 controller. The Sc control signal determines the duty cycle of the 2248 switch and can therefore be used to regulate power transmission. Although only one reverse transfer converter is shown in Fig. 2d, it can be seen that a control signal Sc transmitted in this way can be used to regulate power transfer in a variety of transmission assemblies such as a transformer, a DC-DC converter, an AC-DC converter, an AC-AC converter, a reverse transfer transformer, a full-bridge converter, a half-bridge converter, or a forward transfer converter, for example. As an example of the signal transfer system 100 (Fig. 1), with reference to Fig. 3, according to a third embodiment of the invention, a signal transfer system 3100 can be integrated into a contactless inductive power coupling system 3200 where power is transmitted inductively from a female socket assembly 3212 to a galvanically isolated male connector assembly 3292. A transmitter circuit 3140 integrated into the male connector assembly 3292 can be used to transmit control signals Sc to a receiver circuit 3160 in the female socket 3212. Thus, once the primary coil L1 and secondary coil L2 are aligned, control signals can be passed between the male connector assembly 3292 and the female socket assembly 3212 without the need to align additional components such as optocouplers and the like. When a contactless male connector 3292 is used, for example, to power a laptop computer 3290 that has onboard power cells 3280, the signal transfer system 3100 can be used to detect the presence of the load 3290, which produces a detection signal Sd, and then to provide the female socket 3212 with signals related to the user identity Sid and the serial number Ss, another identifier of the laptop computer 3290. Signals regarding the operating voltage and current required by the PC can be provided as a regulator signal Sq, which can also provide supplementary information, such as information related to the energy level of the cells 3280, for example.Using this Sq signal, the 3100 signal transfer system can be used to select between directly powering the 3290 computer, recharging its 3280 power cells, or both powering and recharging, depending on the default values ​​and predefined criteria. It is also noted that when used to recharge the 3280 cells, the ability to monitor the temperature of the 3280 cells during recharging can be used to prevent overheating. With reference to Fig. 4, a flowchart is presented showing a procedure for transferring a transmission signal through an inductive power coupling according to another embodiment of the invention. With further reference to Fig. 2a, an input signal Sin - Stage (a) and a bit rate signal Fb - Stage (b) are supplied to the transmission circuit 2140. The bit rate signal Fb is then modulated by the input signal Sin, producing a modulated signal Sm - Stage (c). An auxiliary load 2142 is then intermittently connected to the second coil L2 according to the modulated signal Sm - Stage (e). The receiving circuit 2160 monitors the primary current drawn by the primary coil L1 to produce a primary current signal Sp - Stage (e).This primary current signal Sp is then cross-correlated with the bit rate signal Fb to generate an output signal (S0ut) - Stage (f). The basic signal transfer system and procedure described above may vary. For example, it will be appreciated that through the use of such a system, information regarding a load 2280 can be transmitted to the power outlet 2210 through the inductor coils L1 and L2 of the inductive coupling 2200, as a signal superimposed on the transmitted power, without requiring additional data transmission components. Energy coupling efficiency The embodiments of the invention are directed to providing procedures for monitoring the efficiency of energy transmission by means of an inductive power supply comprising at least one primary coil connected to a power source, for inductive coupling with a secondary coil connected to an electrical device. The procedure comprises the steps of: measuring the input energy supplied to the primary coil, measuring the output energy received by the electrical device, communicating the input energy to a processor, communicating the output energy to the processor, and the processor determining an energy loss index.In a specific application, the energy loss index is an efficiency ratio Q, which is the ratio between output energy and input energy. The procedure includes the additional step of disconnecting the primary coil from the power supply if the efficiency ratio Q falls below a threshold value. Typically, the threshold efficiency ratio is in the range of 75% to 95%. In another application, the energy loss index is an efficiency differential A, which is the difference between the output energy and the input energy, and the procedure comprises the additional step of: disconnecting the primary coil from the power supply if the efficiency differential A is above a threshold value. An additional aspect of the technology described in this invention relates to an efficiency monitor for monitoring the efficiency of energy transmission by means of an inductive energy socket of the type that includes at least one primary coil connected to a power supply, for inductive coupling with a secondary coil connected to an electrical device. The efficiency monitor includes: at least one input energy monitor for measuring the input energy supplied to the primary coil; at least one output energy monitor for measuring the output energy received by the secondary coil; at least one processor for determining an energy loss index; and at least one communication channel for communicating the input and output energy to the processor. Typically, the efficiency monitor also includes at least one circuit breaker to disconnect the primary coil from the power supply. Preferably, the input energy monitor is built into the power outlet, and the output energy monitor is built into the electrical device. Optionally, the electrical device comprises at least one transmitter for transmitting the output power to a receiver incorporated in the power outlet. The transmitter may include one or more light-emitting diodes, radio transmitters, optocouplers, or auxiliary charge transmitter circuits, for example. According to preferred embodiments of the invention, the efficiency monitor includes one or more hazard detectors communicating with the processor. Such hazard detectors may include magnetic sensors, heat sensors, electromagnetic radiation sensors, and Hall effect sensors, for example. Reference is made to Fig. 5, which shows a block diagram of a signal transfer system 4100. The signal transfer system 4100 is incorporated into an efficiency monitor 4300 to monitor the efficiency of power transmission by means of an inductive power tap 4210. The inductive power socket 4210 consists of a primary coil 4220 connected to a power supply 4240 through an exciter 4230 that provides the electronics necessary to drive the primary coil 4220. The pulse electronics may include a switching assembly that provides a high-frequency oscillating voltage supply, for example. If a secondary coil 4260 is brought near the primary coil 4220, the pair of coils forms an inductive coupling, and energy is transferred from the primary coil 4220 to the secondary coil 4260. In this way, the power socket 4210 can supply energy to an electrical device 4262 comprising an electrical load 4280 connected in series with the secondary coil 4260. The 4300 efficiency monitor consists of an input power monitor 4122 built into the power socket 4210 and an output power monitor 4124 built into the electrical device 4290, both communicating with a processor 4162. The input power monitor 4122 is configured to measure the input Pin power of the primary coil 4220 and communicates this value to the processor 4162. The output power monitor (4124) is configured to measure the output Pout power received by the secondary coil (4260) and communicates this value to the processor (4162). The processor (4162) is configured to receive the input power Pin and output power Pout values ​​to calculate a power loss index. The power loss index indicates how much power is lost from the inductive coupling. The power loss index can be the efficiency ratio Q, which is the ratio of Pout to Pin, indicating the efficiency of the inductive coupling. Alternatively, the power loss index can be the efficiency differential A, which is the difference between Pout and Pin. The processor 4162 can be additionally or alternatively configured to activate a circuit breaker 4280 by cutting off the primary coil 4220 from the power supply 4240 when the efficiency ratio Q falls below a predetermined threshold or the efficiency differential A rises above a predetermined threshold. Typically, this predetermined threshold for the efficiency ratio Q is in the range of approximately 75% to 95%, and more preferably around 85%. With reference to Fig. 6a, an efficiency monitor 5300 for an inductive power socket 5210 is shown. The inductive power socket 5210 consists of a primary coil 5220 connected to a power source 5240 via an efficiency monitor 5300, all concealed behind a covering layer 5642 of a horizontal platform 5640, such as a desk, kitchen countertop, conference table, or workbench. The covering layer can be a sheet of self-adhesive plastic film, plastic, vinyl, Formica, or wood veneer, for example. In other embodiments, a 5220 primary coil can be concealed beneath or within flooring, such as carpets, rugs, parquet, linoleum, tiles, paving stones, and the like. Alternatively, the 5220 primary coil can be concealed behind or within a vertical surface such as a building wall or cabinet, for example, behind wallpaper, framed canvases, or similar materials. The primary coil 5220 can be used to power an electrical device 5290 such as a computer connected to a secondary coil 5260. The electrical device 5290 is placed on the surface 5642 of a platform 5640 so that the secondary coil 5260 is aligned with the primary coil 5220 beneath it. The efficiency of power socket 5210 is monitored by an efficiency monitor 5300. An input power monitor 5122 is incorporated within power socket 5210 behind platform 5640 and is in direct conductive communication with a processor 5162. An output power monitor 5124 is incorporated within electrical device 5290 and is not physically connected to power socket 5210. The output power monitor 5124 communicates with the processor 5162 through a signal transfer system 5100 comprising a transmitter 5140 incorporated within electrical device 5290 that is configured to transmit a signal to a receiver 5160 incorporated within power socket 5210. The 5140 transmitter can be a standard transmitter, such as those widely used in computing and telecommunications, like infrared, Wi-Fi, or Bluetooth transmitters. In fact, any light-emitting diode, radio transmitter, optocoupler, or other radiation transmitter can be used for which the 5640 platform is translucent. Alternatively, a fiber optic path can be provided through the platform. In certain embodiments, an optical transmitter, such as a light-emitting diode (LED), for example, is incorporated within the power socket 5210 and is configured and operated to transmit electromagnetic radiation of a type and intensity capable of penetrating the housing of the electrical device 5290, and the surface layer 5642. An optical receiver, such as a photodiode, a phototransistor, a light-dependent resistor, or the like, is incorporated within the primary assembly to receive the electromagnetic radiation transmitted through the surface layer 5642. Many materials are observed to be partially translucent to infrared light. It has been found that relatively low-intensity infrared signals from LEDs and similar devices penetrate several hundred micrometers of common materials such as plastic, cardboard, Formica, or paper to a sufficient degree for an optical receiver, such as a photodiode, phototransistor, light-dependent resistor, or similar device, behind a 0.1 mm to 2 mm thick sheet of such material, to receive and process the signal. For example, a signal from an Avago HSDL-4420 LED transmitting at 850 nm at 24 degrees can be detected by an Everlight PD15-22C-TR8 NPN photodiode from behind a 0.8 mm thick sheet of Formica. For signaling purposes, a high degree of attenuation can be tolerated, and penetration of only a small fraction, for example, 0.1% of the transmitted signal intensity, may be sufficient.Therefore, an infrared signal can be used for. provide a communication channel between primary and secondary assemblies galvanically isolated from each other by a few hundred micrometers of wood, plastic, formica, wood veneer, glass or similar. The transmitter 5140 and receiver 5160 can be displaced laterally from the primary coil 5220 and the secondary coil 5260. In preferred embodiments of the invention, however, the transmitter 5140 is located in the center of the secondary coil 5260 and the receiver 5160 is located in the center of the primary coil 5220. This allows alignment to be maintained through 360-degree rotation of the secondary coil 5260 with respect to the primary coil 5220. The 5162 processor is configured to receive the input power (Pin) values ​​directly from the input power monitor (5122) and the output power (Pout) values ​​via the receiver (5160). The 5162 processor then calculates the efficiency ratio Q. In normal operation, as depicted in Fig. 6a, the processor records an efficiency ratio Q greater than a predetermined threshold to ensure uninterrupted power transmission. When the efficiency ratio Q falls below a predetermined threshold, this indicates that power is being drawn from the primary coil 5220 by a power drain other than the secondary coil 5260. Figure 6b is a schematic diagram of the inductive power take-up 5210 of Figure 6a, where a power drain, such as a conductive sheet of metallic paper 5800, is inserted between the primary coil 5220 and the secondary coil 5260. The oscillating magnetic field produced by the primary coil 5220 when connected to a high-frequency oscillating voltage from an exciter 5230 induces eddy currents in the conductive sheet 5800, thereby heating the sheet and draining energy from the primary coil 5220. Such a power drain can be useless and / or dangerous. It will be appreciated that leakage prevention systems that cut off power to the primary coil 5220 if there is no secondary coil 5260 connected to it would not detect this hazard. Unlike prior systems known to the inventors, embodiments of the present invention measure the efficiency ratio Q. Consequently, when energy consumption is introduced, such as that shown in Fig. 6b, for example, the output energy Pout received by the secondary coil 5260 is lower than normal, and the efficiency ratio Q may therefore fall below a predetermined threshold. The efficiency monitor 5300 is thus able to detect the danger. According to certain embodiments, additional detectors (not shown) can be incorporated within the power socket 5210, platform 5640, or electrical device 5290 to monitor other scientific effects that may be indications of potential hazards, such as the magnetic field generated by the primary coil 5220 or the temperature of platform 5640, for example. Such detectors may operate according to one or more of a variety of principles, including, but not limited to, magnetic sensing means, Hall probes, heat sensors, or electromagnetic sensors. The processor 5162 can assess the level of the detected hazard by processing the various received signals according to a predetermined logic sequence. If necessary, the processor 5162 can trip a circuit breaker 5280 by interrupting the primary coil 5220 of the power supply 5240. Depending on the nature of the hazard, the processor 5162 can additionally or alternatively alert a user to the hazard. The alert can be a visual or audible alarm, such as a buzzer or light built into the power transmission surface, or a signal sent to the computer 5290, which displays a warning 5294 on its visual display 5296 or emits a warning sound. In preferred embodiments of the invention, the output energy Pout can be monitored and encoded in the input signal Sin. The coil-to-coil signal generator shown in Fig. 2a can be used to transmit the input signal Sin from a transmitter circuit 2140 (Fig. 2a) incorporated within an electrical device 290 (Fig. 1) and can be recovered by the receiver circuit 2160 (Fig. 2a) incorporated within the power socket 210 (Fig. 1) from the output signal S0ut. The recovered signal can then be communicated to a processor that uses it to calculate the efficiency ratio Q. Reference is made to Figure 7, which shows a flowchart of a procedure for monitoring the efficiency of power transmission by means of an inductive power supply according to a further embodiment of the present invention. The procedure includes the following steps: a) measure the input energy supplied to a primary coil; b) measure the output energy received by an electrical device; c) communicate the Pin input energy to a processor; d) communicate the output energy Pout to the processor; e) determine an energy loss index, such as an efficiency ratio Q or efficiency differential A; f) optionally, disconnect the primary coil from the power supply, for example, if the efficiency ratio Q is below a threshold value (f1) or the efficiency differential A is above a threshold value (f2), thus preventing energy leakage. Primary coil locators A power outlet locator for locating an inductive power outlet of the type comprising at least one primary coil connected to a power supply to inductively couple with a secondary coil connected to an electrical device. Typically, the power outlet locator comprises at least one sensor for detecting the at least one power outlet, at least one processor for receiving a sensor signal from the at least one sensor and calculating at least one coordinate of the location of the at least one power outlet, and at least one user interface for receiving a signal from the processor and communicating the location to a user. Preferably, at least one sensor is selected to detect radiation transmitted by at least one of the power outlets. Typically, at least one sensor is selected to detect an electromagnetic field generated by at least one of the primary coils. Optionally, the processor calculates the distance between the sensor and the power outlet by comparing the intensity of the radiation received by the sensor with a reference value. Typically, the processor determines the direction to the power outlet by comparing the relative intensities of the radiation detected by a plurality of sensors. Alternatively, the location of the power outlet is encoded in a signal transmitted by the power outlet and decoded by the processor. Typically, the user interface comprises a visual display. Optionally, the visual display indicates the direction of the power outlet. Preferably, the visual display indicates the distance to the power outlet. Preferably, the visual display comprises a graphical user interface representing at least a section of a target comprising concentric rings centered on a point indicating the location of the power outlet. Typically, the power outlet is concealed behind a surface, and the target is superimposed on an image of the surface. Alternatively or additionally, the user interface comprises an audible signal. Another aspect of the present invention is to provide an electrical device incorporating a power outlet locator. Typically, the electrical device further comprises at least one secondary inductive coil for powering the electrical device. Optionally, the electrical device further comprises at least one electrochemical energy cell for powering the electrical device and at least one secondary inductive coil connected to the electrochemical cell via a rectifier for charging the electrochemical energy cell. The electrical device may be selected from, but is not necessarily selected from, the group comprising: telephones, personal digital assistants (PDAs), cameras, media players, computers, keyboards, and mice. Reference is made to Fig. 8a, which shows a schematic representation of the power outlet locator 6300 that uses the signal transfer system. The location of an inductive power outlet 6210, concealed behind a surface 6642, is indicated by an arrow 6362 displayed on a visual user interface 6360. The 6210 inductive power socket is connected to a power source typically through a 230 exciter (Fig. 1) that provides the necessary electronic components to drive the 6210 inductive power socket, such as a switching assembly that provides a high-frequency oscillating voltage supply, for example. The 6210 inductive power socket can be incorporated into a vertical surface such as a building wall or cabinet. It can also be concealed behind a surface such as wallpaper or framed canvas. Alternatively, it can be integrated behind a horizontal surface such as a desk, kitchen countertop, conference table, or workbench, made of materials like mica, Formica, or wood veneer. Finally, it can be concealed beneath flooring such as carpets, rugs, parquet, linoleum, tiles, paving stones, and similar materials. It will be evident that when the location of the inductive power tap 6210 is known, a secondary coil 6260 can be aligned with it, as shown in Fig. 8b, for example. Therefore, with reference to Fig. 8b, the inductive power tap 6210 can be inductively coupled with the secondary coil 6260 and thus power an electrical device, such as a computer 6290, connected to the secondary coil 6260. It should be noted that the electrical device, such as a computer 6290, may itself incorporate an integral inductive power tap locator. With reference to Fig. 9, a block diagram is shown representing the main functional components of a 7300 power outlet locator. A 7160 detection assembly, configured and operational, is provided to detect an inductive 7210 power outlet. A 7362 processor, in communication with the 7160 detection assembly, is configured to calculate the location of the 7210 power outlet. A 7360 user interface is provided to communicate the calculated location to a user. The 7160 sensor assembly can incorporate magnetic sensors, such as Hall effect sensors, configured to detect the magnetic field generated by the inductive power outlet directly. Alternatively, the 7160 sensor assembly can incorporate a radio receiver to receive a radio signal transmitted from the power outlet. However, it is worth noting that suitable sensors can be selected to detect specific electromagnetic wavelengths, including ultraviolet radiation, microwaves, radio waves, or even X-rays or shorter wavelengths. Furthermore, the detection assembly can be configured to receive other types of radiation, including mechanical vibrations such as audible and inaudible sound waves (e.g., ultrasonic). As an example, an exemplary 7460 sensing assembly is depicted in Fig. 10, where four 7462a-d sensors, such as volume sensor-based proximity sensors, infrared sensors, ultrasonic sensors, magnetic sensors (such as Hall probes), inductance sensors, capacitance sensors, or the like, are arranged in a diamond configuration. Each 7462 sensor is configured to receive a control signal Sc transmitted from an inductive power socket 7210. The 7362 processor can compare the intensity I of the control signal Sc detected by a 7462 sensor with a reference value Ir to indicate the distance between the 7462 sensor and the 7210 power socket. Furthermore, the diamond configuration provides two perpendicular, opposing pairs of sensors 7462a-b, 7462cd. The intensity I of the control signal Sc is measured by each sensor independently. The processor 7460 can use the differences between the intensities measured by opposing pairs (Ia-Ib), (Ic-Id) to provide vector coordinates indicating the direction of the power pickup 7210. While a two-dimensional vector is calculated using the two-dimensional diamond configuration of sensors described earlier in this invention, it will be appreciated that a three-dimensional vector can be calculated from three pairs of sensors in a tetrahedral configuration. It will be appreciated that the calculation procedure described in this invention is by way of example, for illustrative purposes only. Alternative procedures by which the processor can calculate the direction of the power supply will be familiar to those skilled in the art. Figure 11 shows a block diagram representing a power socket locator 8500. An inductive power socket 8210 transmits a control signal Sc carrying a coded location signal Sl that identifies the location of the inductive power socket 8210. A primary coil 8220 is connected to a power supply 8240 through a switching assembly 8232 and a microcontroller 8234. The switching assembly 8232 is configured to intermittently connect the power supply 8240 to the primary coil 822 at a bit rate frequency f. The location of the primary coil 8220 is encoded in a location signal Sl that is sent to the microcontroller 8234. The microcontroller 8234 is configured to modulate the bit rate signal with the location signal Sl. The voltage applied to the primary coil 8220 is therefore a variable voltage modulated with a frequency f, which carries a coded location signal Sl. It will be appreciated that the variable voltage can produce a radio wave of frequency f that can be transmitted as a control signal Sc. Alternatively, the control signal Sc can be transmitted by means of a dedicated transmitter separate from the primary coil 8220. The 8500 power outlet locator includes an 8160 receiver, an 8542 clock, and an 8544 cross-correlator. The 8160 radio receiver can be tuned to receive radio waves of frequency f so that it can receive the Sc control signal. The 8542 clock produces a fixed reference signal R of frequency f. The 8544 cross-correlator receives both the reference signal R from the 8542 clock and the Sc control signal from the 8160 receiver, and by cross-correlating these signals, the location signal Sl is isolated. Although a digital bit-rate modulated control signal Sc is described above in this invention, it will be appreciated that the control signal Sc can be modulated alternatively in other ways, such as by analog or digital frequency modulation or by amplitude modulation, for example. The location of the power socket 8210 can thus be transmitted to a remote socket indicator 8500, which can then generate the location of the power socket 8210 to a user interface 7360 (Fig. 9). As shown in Figs. 12a-c, a power socket locator 9300 can be incorporated into a mobile phone 9290, for example, thus providing a convenient means of locating hidden inductive power sockets. A graphical user interface 9360, displayed on the mobile phone 9290's visual screen, represents a virtual target 9660, centered on the power socket (not shown) and superimposed on the surface 9640 behind which the power socket is hidden. Although the entire virtual target 9660 is represented by a dotted line in Figs. 12a-c for convenience, normally only section 9661a-c of the virtual target 9660 will be visible on the mobile phone 9290's visual display 9360. The displayed section depends on the mobile phone 9290's location. Therefore, the curvature of the visible concentric arcs can indicate both the direction and the distance to the power source. It will be appreciated that the virtual target 9660 can be displayed against a white background or, alternatively, can be superimposed on an image of the surface 9640, for example, a real-time image produced by the mobile phone 9660's camera (not shown). It is further noted that the 9290 mobile phone can itself carry a secondary inductive coil (not shown) connected to an electrochemical cell via a rectifier for inductive coupling with an inductive power socket and charging of the electrochemical power cell. Optimal alignment between the secondary coil and the inductive power socket can be further indicated by an audible signal such as a ringtone or similar. Particularly useful for visually impaired users, an additional audible signal can be provided to guide the user to the power socket, perhaps verbally or alternatively through other variations in tone, volume, or timbre. It will be evident that in certain situations, such as when the power source of the 9660 mobile phone is completely depleted of power, a 9300 power socket locator that draws power from the 9290 mobile phone is impractical. Therefore, a power socket locator can be a self-powered unit with a separate user interface from that of the 9290 mobile phone. For example, the power socket locator draws power from the secondary inductive coil. Additionally or alternatively, it can include a dedicated electrochemical power source, for example. The relative brightness of four light-emitting diodes mounted at the corners of the mobile phone can indicate both the direction and proximity to a primary coil. Although the 9300 power socket locator is incorporated into a 9290 mobile phone, it is noted that this power socket locator can alternatively be incorporated into other electrical devices such as landline phones, personal digital assistants (PDAs), cameras, media players, computers, keyboards, cursor controllers (e.g., mice), and the like. Secondary coil locators The signal transfer system can be associated with the primary coil and used to detect the location of the secondary inductive coil. For example, on a power tapping surface comprising multiple primary coils, each primary coil can be independently connected to the power source via an exciter. The signal transfer system can be used to identify the primary coil closest to the location of a secondary coil. Typically, the primary coils can be driven at multiple energy levels, so a low energy level is used to locate the secondary coil, and a higher energy level is used to transfer power when a secondary coil is located. The secondary coil may be connected to a transmission circuit comprising an auxiliary load connectable to the secondary coil via a half-wave rectifier, such as a diode. The transmission circuit may also include a leveling capacitor, a low-power current source, and a DC-to-DC converter. When in sensing mode, the exciter energizes each primary coil sequentially at low power. When a secondary coil is close enough to a primary coil to inductively couple with it, the low-energy pulse is transferred from the primary coil to the secondary coil. An AC voltage is induced in the secondary coil, activating the transmission circuit. The half-wave rectifier produces a DC current that flows through the auxiliary load. The secondary coil transmits a control signal through the transmission circuit. Because half-wave rectification is used, even harmonics are generated at the power transmission frequency. These can be detected by a receiving circuit connected to the primary coil, for example, by cross-correlating the power transmission frequency with a reference clock frequency. The resistance of even harmonic signals can indicate the proximity of the primary coil to the secondary coil. Once a secondary coil is detected, the exciter can switch the nearest primary coil into power transmission mode, typically to a higher energy setting. It will be noted that in applications where a primary electrical load is connected to the secondary coil via an AC-DC power converter performing half-wave rectification, even harmonics are produced whenever the secondary coil is coupled to a primary coil, regardless of whether the auxiliary load is connected. The resistance and phase of the odd and even harmonics can be continuously monitored during power transmission so that if the secondary coil is displaced or withdrawn, it will be easily detected. Optionally, the transmission circuit can be deactivated when power is supplied to the electrical load. Alternatively, when the primary load is connected to the secondary coil via a half-wave rectifier, the auxiliary load can be distributed entirely. Figure 13 shows another signal transfer system 2101, which, however, is not part of the claimed invention. The signal transfer system 2101 is used to locate a secondary coil L22 connected to an electrical load 2281, which is placed somewhere on a multi-coil power transmission surface 2211. The multi-coil power transmission surface 2211 comprises an array of primary coils Un, each connected to an exciter 2231 connected to a power source 2241. The signal transfer system 2101 includes a transmitting circuit 2141 connected to the secondary coil 2221 and a receiving circuit 2161 connected to the exciter 2231. The transmitting circuit 2141 includes a half-wave rectifier 2144 connected to an auxiliary load 2142, and the receiving circuit 2161 is configured to detect second harmonic signals in the power supplied to the primary inductive coil Un when the secondary inductive coil L22 is coupled to it. Exciter 2231 is configured to selectively operate each primary inductor coil Un in turn, preferably at low energy, to identify which primary inductor coil is closest to the secondary inductor coil L22. When a secondary inductor coil L22 is detected, exciter 2231 is configured to operate the primary inductor coil Un closest to the secondary inductor coil L22 at high energy. It will be appreciated that for some purposes it may be desirable to disconnect the transmission circuit 2141 after the secondary inductor coil L22 is coupled to a primary coil Un. Therefore, a number of related technologies are presented that utilize signal transfer systems through inductive power coupling to regulate power and to detect and align the two coils. In the claims, the word "comprising" and variations such as "comprising," "comprising," and the like indicate that the listed components are included, but do not generally exclude other components.

Claims

1. An efficiency monitor (4300, 5300) for monitoring the efficiency of an inductive power transmission between an inductive power socket (4210, 5210) and an electrical device (290, 4290, 5290), the inductive power socket (4210, 5210) comprising at least one primary coil (4220, 5220) connected to an electrical power supply, to be inductively coupled with a secondary coil (4260, 5260) of the electrical device (290, 4290, 5290) that is connected to an electrical load (4280, 5280), the efficiency monitor (4300, 5300) comprising: at least one processor (4162, 5162) incorporated in the inductive power socket (4210, 5210); and at least one input energy monitor (4122, 5122), incorporated in the inductive energy socket (4210, 5210), and configured to measure an input energy (Pin) supplied to the primary coil (4220,5220) and to provide the processor (4162) with an input energy value obtained by measuring said input energy; and characterized by at least one output energy monitor (4124, 5124), incorporated in the electrical device (290, 4290, 5290) and configured to measure an output energy (Pout) received by the secondary coil (4260, 5260) and communicate an output energy value obtained by measuring said output energy to the processor (4162); wherein said at least one processor (4162) is configured to determine an energy loss index based on at least one of: an efficiency ratio Q, defined as the ratio of said output energy to said input energy; and an efficiency differential A, defined as the difference between said output energy and said input energy.

2. The efficiency monitor of claim 1, further comprising at least one transmission circuit (2140, 5140),incorporated in the electrical device (290, 4290, 5290), for wirelessly transmitting a signal to a receiver (2160, 5160) incorporated in the inductive power socket (4210, 5210), wherein the signal carries data relating to said output power (Pout), said transmission circuit (2140) comprising: an auxiliary load (2142) selectively connected to the secondary inductive coil, a microcontroller (2146) and a frequency divider (2145) for modulating a bit rate signal (Fb) with an input signal (Sin) to create a modulated signal (Sm), a switch (2147) for intermittently connecting said auxiliary load (2142) to the secondary inductive coil (4260, 5260) according to said modulated signal, wherein said modulated signal is a representation of at least the data relating to the output power (Pout); and where, a correlator (2164) of said inductive energy intake (4210,5210) is configured to extract said data-carrying signals from a current monitor (2162) and pass the data to the processor (4162, 5162).

3. The efficiency monitor of claim 2, wherein said transmission circuit (2140) is selected from a group consisting of: light-emitting diodes, radio transmitters, optocouplers, and combinations thereof.

4. The efficiency monitor of claim 2 or 3, wherein the data further comprises information selected from a group consisting of voltage, current, temperature, operating power consumption required by the electrical load, and any combination thereof.

5. The efficiency monitor of any one of claims 1 to 4, wherein the inductive power input (4210,5210) further comprises at least one circuit breaker (4280) configured to disconnect the primary coil (4220) from the power supply (4240) based on the energy loss rate with respect to predetermined values.

6. The efficiency monitor of any of claims 1 to 5 further comprising hazard detectors in communication with said processor (4162, 5162), wherein said hazard detectors are selected from a group consisting of: magnetic sensors, heat sensors, electromagnetic radiation sensors, and Hall probes.

7. An electrical device (290, 4290, 5290) comprising at least one secondary coil (4260) for inductive coupling to a primary coil (4280) of an inductive power socket (4210, 5210), said electrical device (290, 4290, 5290) being configured to provide signals carrying data relating to the output power (Pout) received by the secondary coil (4260,5260) to a processor 4162, 5162) incorporated in the inductive power socket (4210, 5210) for an efficiency monitor according to claim 1, used to monitor the efficiency of inductive power transmission between the inductive power socket (4210, 5210) and the electrical device (290, 4290, 5290), the electrical device (290, 4290, 5290) further comprising: at least one output power monitor (4124) incorporated in the electrical device (290, 4290, 5290) and configured to measure the output power (Pout) received by the secondary coil and to communicate an output power value obtained by measuring said output power to the processor (4162); and a transmission circuit (2140) configured to wirelessly communicate said signals carrying data relating to said output energy (Pout),comprising the transmission circuit (2140): an auxiliary load (2142) selectively connected to the secondary coil (4260); a microcontroller (2146) and a frequency divider (2145) configured to modulate a bit-rate signal with an input signal to create a modulated signal; a switch (2147) for intermittently connecting the auxiliary load (2142) to the secondary coil (4260) according to the modulated signal; and wherein the modulated signal is a representation of at least the data relating to the output energy (Pout).

8. The electrical device (290, 4290, 5290) of claim 7, wherein the input signal is further derived from an external signal.

9. An inductive power socket (4210, 5210) comprising an efficiency monitor (4300, 5300) according to claim 1.

10. The inductive power socket (4210, 5210) according to claim 9, wherein the inductive power socket (4210,5210) further comprises at least one circuit breaker (4280) configured to disconnect the primary coil (4220) from the power supply (4240) based on the energy loss index with respect to predetermined values.

11. A method of using the efficiency monitor of one of claims 1 to 4, comprising the steps of: step (a) - continuously measuring the input energy supplied to the primary coil; step (b) - continuously measuring the output energy received by the secondary coil; step (c) - communicating, via a wired connection, the measured input energy values ​​to the processor; step (d) - communicating, via said transmission circuit (2140), the measured output energy values ​​to said processor; and step (e) - said processor determining an energy loss index based on at least one of: an efficiency ratio Q, defined as the ratio of said output energy to said input energy,and an efficiency differential A, defined as the difference between said output energy and said input energy.

12. The method of claim 11, comprising at least one additional step (f) - disconnecting the primary coil from the power supply if: said efficiency ratio Q is below a threshold value, or said efficiency differential A is above a threshold value.

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