Field of the invention

The invention relates to a method, a system and a device for transferring electric power from a power harvesting device sitting on a live phase wire of a high-voltage power line to a power supplying device located in the mast structure of that same power line.

Background

Electrical energy is often transferred on high-voltage power lines supported by mast structures. The electricity is generated in power plants that are often located in remote places, therefore creating the need for a long network of power lines running across remote and harsh areas to the point of consumption on industrial sites or in more densely populated places.

Detection of potential malfunctions on power lines and running diagnostics, remote problem solving and/or localization of such instances is a challenge for the operators of high-voltage power lines. A particular problem is powering the necessary surveillance equipment. Direct connection to high-voltage power lines for the purpose of tapping of power for low-voltage surveillance equipment is both costly and complicated and can cause instability in the operation of the high-voltage power line in question. Operators are forced to resort to other means of accessing power such as building small transformer stations incorporating bulky isolation transformers or by connection to external power sources like small wind turbines, solar cells, diesel generators or batteries. The cost and complexity of such installations has severely hampered deployment of surveillance and monitoring devices even though such devices are much needed for secure operation of their grid.

It is possible to harvest energy from an AC carrying conductor without connecting directly to it electrically. This is achieved by inductive power transfer by using a current transformer, where the current carrying conductor is passed through an opening core of a current transformer with secondary windings wound around the core. A current in the current carrying conductor that passes through the core of the current transformer creates an electromagnetic field around itself generating current in the secondary winding which can be harvested and used as a power source. US 2014/160820 discloses an electrical current transformer for mounting on a power distribution line comprising a split core and two secondary windings connected to each other through one end of the winding at a centre tap, where the tap control connects or disconnects the centre tap to the two rectifiers for enabling winding selection in additive, subtractive and self-cancelling manner.

US 2010/0084920 discloses a current transforming harvester for harvesting power from a conductor on a pre-existing power grid by capturing energy via magnetic flux from the conductor. The current transformer has a split core for attachment to the conductor via a clamping mechanism.

WO 2017/138026 discloses a device for extracting power from a current-carrying conductor's and regulate to a stable DC voltage power source. The regulated DC voltage can be used to power the internal electronic circuitry of the power supply unit and along with the PSU.

The drawbacks of these and other prior art systems is that they are not able to extract large amounts of power from the conductor due to shortcomings such as voltage drop and heat generation. Furthermore, these systems have a problem with the complexity of regulating and controlling the power generation and getting rid of excessive power, often in the form of heat generation that will damage the equipment if left unattended. Some of these problems are solved in WO 2019/030781, which discloses a system for harvesting electrical power from the electromagnetic field surrounding a conductor of a high-voltage power line using current transformers for powering surveillance equipment's.

Even if some surveillance devices may be located on a conductor of a high-voltage power line, other devices require to be located on the masts carrying the phase wires as they are not able to operate under the movement of the power lines due to different weather and environmental conditions. It would therefore be advantageous to be able to have access to plug in power outlets in remote places on a power grid for maintenance operations and safety or emergency reasons. However, there are many challenges with transferring electricity harvested on a phase wire to the mast-structure such as crossing the isolation boundary between the live phase wire and the ground-based mast structure, short circuiting, means of power transfer, conversion of transferred power to electrical power and problems with regulating power harvesting and power transfer.

Summary of the Invention

The invention relates to a method, a system and a device for transferring electric power from a power harvesting device sitting on a live phase wire of a high-voltage power line to a power supplying device located in the mast structure of that same power line, effectively crossing the isolation boundary between the live phase wire and the ground-based mast structure. The power supplying device provides access to low-voltage electrical power thus working as a "plug" suitable for any type of appliances that require electricity for its operations. The present invention provides a method and a system for safely transferring electric power from a power harvesting device clamped onto a live phase wire of a high- voltage power line using laser power and a fibre cable to a power supplying device located in the electrically ground-based mast structure of that same power line. The power supplying device incorporates a conversion device for converting the laser power back to electricity. The apparatus, system and method of the present invention are designed to facilitate the use of power harvested from an electromagnetic field surrounding current carrying phase wire of high-voltage power line and transfer a portion of that power safely to the electrically ground-based mast structure. The device of the present invention is designed as a laser-based power supply system connected to a power supplying device through a fully dielectric optical fibre cable for transmitting a high-power laser light between the power harvesting device located on the live phase wire and the power supplying device mounted onto the electrically grounded mast. This is possible as the fully dielectric optical fibre cable provides the high-voltage isolation between the live phase wire and the electrically ground-based mast structure that is required to safely transmit the electrical power.

The present invention provides a novel way of harvesting and supplying DC power for a high-power pump laser diode, which then transmits a high-power laser beam through fibres in an optical fibre cable to a power conversion and supply device located in the electrically ground-based mast structure. The power harvesting and conversion system of the present invention solves the shortcomings of prior art systems including a limited power supply, which would be insufficient to power a high-power laser diode, power conversion and storage in the mast-based power supply device, and regulation and controlling the power generation, laser power transmission and power storage in the system.

In some embodiments, the power harvesting and supply system presented herein uses a combination of a power harvesting device clamped onto phase wire of a high voltage power line and a power supplying device mounted onto an electrically ground-based mast structure carrying the high-voltage phase wire. A fully dielectric optical fibre cable, connecting the power harvesting device and the power supplying device, enables the transmitting of high-power laser beam from the power harvesting device clamped onto high-voltage phase wire to the power supplying device mounted onto the electrically ground-based mast structure in a safe manner. The power harvesting device can transmit the high-power laser beam continuously, in a pulsed manner or in burst mode, all based on the power available at the power harvesting device side and/or the power requirements in the power supplying device side. The optical cable may comprise separate fibres to manage communication between the power harvesting device and the power supplying device for example to manage the power regulation of the whole system. The power harvesting device can be directly controlled to turn on and off individual current transformer units without generating heat in the device on the power harvesting side to control charging of the power storage device of the power supply on the power supplying device side. The communication between the power harvesting device and the power supplying device may also be done by using a wireless connection.

In some embodiments, the power harvesting section of the power harvesting device of the present invention uses a power harvesting technique which can generate hundreds of watts of electrical power with minute power losses and heat generation in the regulation circuitry and within the confined space it will be located. The power regulation circuitry of each current transformer unit used in the power harvesting section operates with a shunting method, which totally short-circuits the secondary winding of each current transformer in each unit when not needed. This terminates power harvesting of that particular current transformer unit and minimizes magnetic flow in the current transformer cores, which minimizes or even eliminates magnetic flow in the core material, eliminates generation of eddy currents and the associated heat generation and vibration in the core material. Furthermore, the electrical power output of each current transformer unit is connected in parallel to form a common power output for the laser beam generating device of the invention. Therefore, the laser beam generating device together with all control and supervision electronics of the power harvester constitutes a common load for each rectifier of the current transformer unit(s) of the power harvesting device, instead of traditional load component for the regulation of the power harvesting. Prior art devices have been arranged by having the ends of the secondary windings of the current transformers connected directly together, which drastically reduces the power harvesting capabilities as one end of a secondary winding is connected directly to a wire of another secondary winding. In contrast to this, the parallel connection of the electric power outputs of the current transformer unit(s) to the common load eliminates power losses as the secondary windings of each current transformer are not affected by other current transformers in the power harvesting section of the device. Furthermore, by totally shorting the ends of the individual secondary winding and by connecting each current transformer unit to the common load in parallel provides a power harvesting system with cold regulation, which makes it possible to harvest sufficient amount of energy to produce laser beam through a high-power pump laser diode from a phase wire of high voltage power lines based on demand. The electrical output of the power harvesting section can be internally controlled within the circuitry of the power harvesting section by switching each current transformer unit on and off. This is beneficial for maintaining function of the control components of the power harvesting section and when supplying surveillance devices mounted on a phase wire with electricity. The electrical output of the power harvesting section can be externally controlled from a power supplying device on the mast structure, as discussed above, through a communication link in the optical cable for demand-based laser power transmitting to the power supplying device.

In some embodiments, the novel method and system of devices for transmitting power in the form of laser beam through an optical fibre cable from a power harvesting device clamped onto a phase wire of high voltage power line to a power supplying device mounted onto the electrically ground-based mast structure comprises a laser to electricity conversion unit for converting the laser beam into electricity again. The laser to electricity conversion unit may further comprise a thermoelectric unit, photovoltaic conversion unit, or a combination of both. A thermoelectric unit converts an incoming laser beam to heat by using one or more lenses to project the laser beam over heat absorbing material of a laser to heat conversion unit. The laser to heat conversion unit further comprises a thermoelectric generator unit for converting heat generated by the incoming laser beam to an electric power using temperature difference between a hot and a cold side provided in the device and placing Peltier modules between a hot surface heated by a laser beam and a cold side cooled by air ventilation. When the laser beam enters the power supplying device it is passed through a scattering lens or lenses, that distribute a narrow metal cutting laser beam over a larger surface area of the heat absorbing material of a thermoelectric generator unit designed to generate electricity according to the Peltier effect or other known thermoelectric conversion methods. Between the heat absorbing material (the "hot side") and a cooling material (the "cold side") an array of the Peltier modules are tightly pressed between the heat absorbing material and the heat sink that acts as the cooling material. This ensures that the heat generated by the laser beam and stored in the heat absorbing material, only passes through the Peltier modules to the cooling material. A photovoltaic conversion unit may be used to convert the incoming laser beam to an electric power by distributing the laser beam over photosensors with lenses and mirrors for the conversion of light into electricity with semiconducting materials, which exhibit the photovoltaic effect. The photovoltaic conversion unit produces heat during operation, which may be used by a thermoelectric generator unit to contribute to the electricity conversion. The laser to electricity conversion unit may be positioned in a heat isolated chamber on the mast structure to prevent heat loss into the surrounding environment and to protect other components of the power supplying device.

In some embodiments the output from the thermoelectric generator unit is in the form of electric power, which may be regulated by a power supply unit to a stable DC voltage level. The power supply unit can further charge a power storage device, (which can store excessive power generated to balance irregularity in the power generation by the power harvesting device and the power demand on the power supplying device side. In some embodiments using supercapacitors instead of conventional batteries, secures long lasting maintenance free operation of the present system and devices.

In some embodiments the method, system and devices of the present invention is controlled by a power regulation unit. The power regulation unit monitors, controls and regulates the power generation of the power harvesting device and communicates with the power harvesting device to secure safe and effective operation of the whole system. The, power regulation unit may communicate with the power harvesting and transfer device on the phase wire through wireless technology or through a communication link in the optical fibre cable to regulate the transmitting of laser power over the optical fibre cable. This provides means to control and regulation of power transfer to the power supply device in the mast structure based on need in the power supply device. The power regulation unit may therefore give instructions to increase, decrease or to turn off the power generation completely by connecting or disconnecting the load connected to the power output of the current transformer units. The power regulation unit further monitors and measures several parameters in the power generating unit such as currents, voltages and temperature values, as well as controlling the charging of the power storage device.

The device and method of the present invention is therefore suitable for safely transferring electric power from a power harvesting device on a phase wire of a high-voltage power line to a power supplying device located in the electrically ground-based mast structure of that same power line. The combination of one or more of the following embodiments provide the solutions presented herein: a) use of a power harvesting device designed to transform the electromagnetic field surrounding current carrying phase wire of high- voltage power line to a low-voltage power source, b) using the low-voltage power to power feed a high-power pump laser diode to transmit a laser beam through an optical cable to a power supplying device, and c) using lenses and or mirrors within the power supplying device to distribute the high-power laser beam over a large area of a heat absorbing material or photosensors to convert laser power to electrical power, and d) the unique control and regulation of power harvesting and transfer to the power supply, which provide the ability to tap off power from high-voltage power lines for the purpose of feeding low- voltage appliances located across the isolation boundaries between the live phase wire and the ground-based mast structure.

It is an object of the present invention to overcome and/or ameliorate the aforementioned drawbacks of the prior art and to provide an improved and/or alternative and/or additional method or device for transferring electric power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high- voltage power line. It is one preferred object of the present invention to provide a method and device to facilitate generating electricity from a laser beam using a high-power pump laser diode generating a laser beam from the electricity generated by the power harvesting device. Moreover, it is a preferred object of the present invention to provide a method and device, preferably designed to transfer electric power from a power harvesting device on a phase wire of high-voltage power line to a power supplying device located on an electrically ground-based mast structure via an optical fibre cable. Another preferred object of the present invention is to provide a device for thermoelectric generation with a laser to heat conversion unit and a thermoelectric generator unit according to the Peltier principle.

The object(s) underlying the present invention is (are) particularly solved by the features defined in the independent claims. The dependent claims relate to preferred embodiments of the present invention. Further additional and/or alternative aspects are discussed below.

Thus, at least one of the preferred objects of the present invention is solved by an apparatus for harvesting and transferring power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high- voltage power line. The apparatus comprises a) a power harvesting and transfer device mounted on the phase wire of high-voltage power line where the power harvesting and transfer device comprises i) a power harvesting section comprising one or more current transformer units, ii) a control and supervising section, and iii) a high-power pump laser diode for converting DC power from the power harvesting unit to a laser beam. The apparatus further comprises b) a power supplying device mounted on the ground-based mast structure, where the power supplying device comprises i) a laser to electricity conversion unit, ii) an electric power output, iii) a power supply unit, iv) a power storage device, and v) a power regulation unit, and the apparatus further comprises c) an optical cable for transmitting the laser beam from the power line module to the supplying device. The power output of the one or more current transformer units are independently connectable to the high-power pump laser diode forming a common load for the current transformer units of the power harvesting section, and the current transformer units are independently switched on or off based on electricity required by the power supplying device.

Another preferred object of the present invention is solved by a system for harvesting and transferring power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high-voltage power line. The system comprises i) a power harvesting and transfer device (mounted on the phase wire of high-voltage power line the power harvesting and transfer device comprising: a power harvesting section for harvesting electric energy from the electromagnetic field surrounding the phase wire, the power harvesting section comprising one or more current transformer units, a control and supervising section, and a high-power pump laser diode for converting DC power from the power harvesting unit to a laser beam, ii) a power supplying device mounted on the ground-based mast structure, the power supplying device comprising a laser to electricity conversion unit, an electric power output, a power supply unit for regulating the output from the laser to electricity conversion unit, a power storage device for storing DC power from the power supply unit, and a power regulation unit for monitoring the operation of the power supplying device and for controlling charging and discharging of the power storage means, and iii) an optical cable for transmitting the laser beam from the power line module to the supplying device. The power output of the one or more current transformer units are independently connectable to the high-power pump laser diode forming a common load for the current transformer units of the power harvesting section, and the current transformer units are independently switched on or off based on electricity required by the power supplying device.

One preferred object of the present invention is solved by a method for transferring electric power from a phase wire of high-voltage power line to a device located in a ground-based mast structure supporting the high-voltage power line. The method comprising the steps of: a) arranging a power harvesting device comprising one or more current transformer units on a phase wire of high-voltage power line, b) harvesting electric energy from the electromagnetic field surrounding the phase wire of the high-voltage power line using a power harvesting unit, c) converting electrical power from the power harvesting unit to a laser beam using a high-power pump laser diode, d) transmitting the laser beam to the power supplying device using an optical cable, and e) generating electrical power output using a laser to electricity conversion unit in the power supplying device.

The power outputs of the one or more current transformer units are independently connectable to the high-power pump laser diode forming a common load for the current transformer units of the power harvesting device, and the current transformer units are independently switched on or off based on electricity required by the power supplying device.

Another preferred object of the present invention is solved by an system for transferring electric power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high-voltage power line. The system comprises a) a power harvesting and transfer device mounted on the phase wire of high-voltage power line where the power harvesting and transfer device comprises i) a power harvesting section comprising one or more current transformer units, ii) a control and supervising section, iii) a laser diode power controller, and iv) a high-power pump laser diode for converting DC power from the power harvesting unit to a laser beam. The apparatus further comprises b) a power supplying device mounted on the ground-based mast structure, where the power supplying device comprises i) a laser to electricity conversion unit, ii) an electric power output, iii) a power supply unit, iv) a power storage device, and v) a power regulation unit, and the apparatus further comprises c) an optical cable for transmitting the laser beam from the power line module to the supplying device. The power regulation unit communicates with the control and supervising section and/or the laser diode power controller for dynamically including or excluding current transformer units from the high-power pump laser diode based on required electrical power of the power conversion and supply device.

Another preferred object of the present invention is solved by an apparatus for transferring electric power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high-voltage power line. The apparatus comprises i) a power harvesting device, where the power harvesting device further comprises a power harvesting unit, and a high-power pump laser diode, ii) an optical fibre cable, and iii) a power supplying device, where the power supplying device further comprises a laser to heat conversion unit and a thermoelectric generator unit, where the thermoelectric generator unit further comprises heat absorbing material, Peltier modules, cooling material, and DC power output. Furthermore, the laser to heat conversion unit comprises a scattering lens which distributes a laser beam from the optical cable over a surface area of the heat absorbing material generating DC power output from the thermoelectric generator unit.

Another preferred object of the present invention is solved by a method for transferring electric power from a phase wire of high-voltage power line to a device located in a ground- based mast structure supporting the high-voltage power line. The method comprising the steps of:

Furthermore, the laser to heat conversion unit comprises a scattering lens which distributes a laser beam from the optical cable over a surface area of the heat absorbing material of the thermoelectric generator unit, said thermoelectric generator unit further comprising Peltier modules, cooling material and DC power output.

One of the preferred objects of the present invention is solved by an apparatus for generating electricity from a laser beam. The apparatus comprises i) a DC source, ii) a high-power pump laser diode generating a laser beam from the DC source, iii) an optical fibre cable, and iv) a power supplying device, where the power supplying device further comprises a laser to electricity conversion unit comprising a scattering lens which distributes a laser beam from the optical cable over onto an electric generating material for generating electrical power output from the power supplying device.

Another preferred object of the present invention is solved by an apparatus for generating electricity from a laser beam. The apparatus comprises i) a laser beam source, ii) a power supplying device, where the power supplying device further comprises a laser to electricity conversion unit, where the laser to electricity conversion unit further comprises a connector inlet for a laser beam and where the laser to electricity conversion unit comprises a scattering lens which distributes a laser beam from the optical cable over onto an electric generating material for generating electrical power output from the power supplying device.

One of the preferred objects of the present invention is solved by an apparatus for transferring electric power from a phase wire of a high-voltage power line. The apparatus comprises i) a power harvesting device mounted on a phase wire of a high-voltage power line, ii) a high-power pump laser diode, and iii) an optical fibre cable. Furthermore, the power harvesting device provides DC power for the high-power pump laser diode to generate a high-power laser beam to be transported from the power harvesting device by the optical fibre cable.

Another preferred object of the present invention is solved by an apparatus for generating a laser beam from a phase wire of a high-voltage power line. The apparatus comprises: i) a power harvesting device, mounted on a phase wire of a high-voltage power line, the power harvesting device further comprises a) a power harvesting section, b) a control and supervising section, c) a laser diode power controller, and the power harvesting device further comprise a high-power pump laser diode. Furthermore, the power harvesting device provides DC power for the high-power pump laser diode to generate a high-power laser beam.

Another preferred object of the present invention is solved by an apparatus for transferring electric power from a phase wire of a high-voltage power line to a device located on an electrically ground-based mast structure supporting the high-voltage power line. The apparatus comprises: a power harvesting device, where the power harvesting device further comprises a power harvesting section, and a high-power pump laser diode, ii) an optical fibre cable, and iii) a power supplying device, where the power supplying device further comprises a laser to heat conversion unit, a thermoelectric generator unit, where the thermoelectric generator unit further comprises heat absorbing material, Peltier modules, cooling material, and DC power output. Furthermore, the laser to heat conversion unit comprises a scattering lens which distributes a laser beam from the optical cable over a surface area of the heat absorbing material generating DC power output from the thermoelectric generator unit.

In the present context the term "laser-based power supply system" refers to a system and apparatus or apparatus comprising at least a power harvesting unit, a power generating unit, a laser diode and an optical cable, where the laser beam generated from the harvested power of the power harvesting unit is converted into electric power.

In the present context the term "power harvesting device" refers to a device which transforms the electromagnetic field surrounding alternative current (AC) carrying phase wire of a high-voltage power line to a stable DC voltage power source.

In the present context the term "power supplying device", refers to a device located in the mast structure of a power line which transforms or converts a laser beam from the power harvesting device to electric power and makes it available to appliances that require low- voltage electricity for their operations.

In the present context the term "high-power pump laser diode" refers to a device which uses the DC power from the power harvesting device to generate and transmit a high- power laser beam through fibres in an optical cable to the power supplying device.

In the present context the term "laser to heat conversion unit" refers to a unit which converts a laser beam into heat in or near the power supplying device.

In the present context the terms "thermoelectric unit" and "thermoelectric generator unit" are used equally for a device which converts heat generated by the incoming laser beam to an electric DC power output using temperature difference between the hot and the cold side provided in the device, such as placing Peltier modules between a hot surface heated by a laser beam and a cold side cooled by air ventilation or liquid based cooling.

In the present context the term "power supply unit" refers to a device for regulating the power output from the laser to electricity conversion unit and for directing the generated electricity to and from a power storage device.

In the present context the term "power storage device" and "power storage means" refer to a device for storing excessive DC power generated by the power harvesting device for later use.

In the present context the term "power regulation unit" refers to a device which monitors, controls and regulates the power supplying device and communicates with the power harvesting device of the invention and it also controls the charging of the SPS bank. In the present context the term "cooling material" refers to a bar or block of heat absorbing material such as heat absorbing metal.

In the present context the term "heat absorbing material" refers to a heat sink providing a large surface are to be contacted with cooling media of a liquid or air phase.

All embodiments listed below relate to both the apparatuses, system and the method of the present invention.

In an embodiment of the present invention the power harvesting section comprises one or more current transformer units, where each current transformer unit comprises i) a core configured to be located around a primary wire and one secondary winding arranged around each core, ii) an AC to DC rectifier, and iii) a shunting unit configured to totally short the ends of each secondary winding, where the electrical power output of each current transformer unit is connected in parallel to form a common power output.

In an embodiment of the present invention the common power output of current transformer units supplies power all control and supervision electronics and the high-power pump laser diode.

In an embodiment of the present invention the power harvesting device comprises i) a power harvesting section, ii) a control and supervising section, and iii) a laser diode power controller.

In an embodiment of the present invention the laser to electric power conversion unit comprises a laser to heat conversion unit and a thermoelectric generator unit.

In an embodiment of the present invention the thermoelectric generator unit further comprises i) heat absorbing material, ii) Peltier modules, iii) cooling material, and iv) electrical power output.

In an embodiment of the present invention the laser to electricity conversion unit comprises a photovoltaic conversion unit.

In an embodiment of the present invention the photovoltaic conversion unit comprises i) a photovoltaic chamber, ii) one or more scattering lenses, a mirror structure, iii) photovoltaic cells, iv) heatsinks, and v) photovoltaic electric output.

In an embodiment of the present invention the photovoltaic conversion unit further comprises vi) thermoelectric generating modules, and vii) thermoelectric output .

In an embodiment of the present invention the mirror structure comprises a number of highly reflective mirrors arranged in a pyramid or conically shaped form. In an embodiment of the present invention heatsink units/heatsink material is arranged to cover the outside wall of the photovoltaic chamber.

In an embodiment of the present invention the photovoltaic cells are arranged on five walls inside the photovoltaic chamber.

In an embodiment of the present invention the laser to electric power conversion unit comprises a unit selected from, but not limited to a laser to heat conversion unit in combination with a thermoelectric generator unit, or a photovoltaic conversion unit.

In an embodiment of the present invention the power harvesting section comprises i) at least one current transformer unit, ii) a DC/DC regulation module, and iii) a charging control.

In an embodiment of the present invention the power harvesting section comprises one or more current transformer units, where each current transformer unit comprises: i) a core configured to be located around a primary wire, ii) one secondary winding arranged around the core, wherein the secondary winding has a first end and a second end, iii) a rectifier configured to convert an alternating current to a direct current, wherein the rectifier comprises two AC connections for alternating current and two DC connections for direct current, wherein the first end and the second end of the secondary winding are connected to the AC connections of the rectifier, iv) a shunting unit arranged and configured to totally short circuit the ends of the secondary winding, wherein an electrical power output of each current transformer unit is connected in parallel to form a common power output.

In an embodiment of the present invention the common power output of current transformer units supplies power all control and supervision electronics and the high-power pump laser diode.

In an embodiment of the present invention all control and supervision electronics and the high-power pump laser diode comprise a common load connected to electrical power output of each current transformer unit in parallel.

In an embodiment of the present invention the electrical connections of the rectifiers that are connected to the load element are connected in parallel.

In an embodiment of the present invention each shunting unit comprises a shunt controller unit for controlling the state of the respective shunting unit.

In an embodiment of the present invention each shunt controller unit comprises a voltage level state input and is configured to control the state of the respective shunt unit in dependence of the voltage level state input. In an embodiment of the present invention each voltage level state input is based on a voltage across the load element.

In an embodiment of the present invention each shunt controller unit comprises a clock input, and wherein each controller unit is configured to only change a state of the respective shunt unit in dependence of the clock input.

In an embodiment of the present invention the system further comprises a zero-crossing detection element for detecting zero crossing states of a sensed current.

In an embodiment of the present invention system further comprises a system control unit, wherein the system control unit is configured to generate the voltage level state inputs for each shunt controller unit based on the voltage across the load element.

In an embodiment of the present invention each rectifier comprises a plurality of MOSFETs, such as at least 4 MOSFETs.

In an embodiment of the present invention each shunting unit comprises a plurality of MOSFETs, such as at least 2 MOSFETs.

In an embodiment of the present invention the apparatus further comprises a power supply unit.

In an embodiment of the present invention the DC power output from the thermoelectric generator unit is connected to the power supply unit, that stabilizes the DC voltage level and handles the charging and discharging of the power storage device.

In an embodiment of the present invention the apparatus further comprises a power regulation unit.

In an embodiment of the present invention the optical cable further comprises a separate optical fibre to provide a communication channel between the power harvesting device and the power generating device for power regulation of the apparatus.

In an embodiment of the present invention the power supplying device may comprise an AC and/or DC power output.

In an embodiment of the present invention the power regulation unit comprises a DC to AC inverter for generating an AC power output.

In an embodiment of the present invention the optical cable exits the power harvesting device and enters the laser to heat conversion unit of the power generating device through an optical fibre connector adapted for high-power laser transmission. In an embodiment of the present invention the laser to heat conversion unit is contained in a heat isolated chamber.

In an embodiment of the present invention the Peltier modules are wired in serial and/or parallel configuration.

In an embodiment of the present invention the power harvesting device and power generating device communicate through a separate optical fibre in the optical cable or use a wireless connection for power regulation of the apparatus.

In an embodiment of the present invention the power regulation unit monitors and measures one or more parameters in the power generating device, such as, but not limited to currents, voltages and heat.

In an embodiment of the present invention the cooling material provides heat sink cooling on a cold side of the thermoelectric generator unit, which can be based on one of, but not limited to, chimney effect, air cooling fans or liquid cooling method.

In an embodiment of the present invention heat sink cooling of the cooling material of the thermoelectric generator unit is based on natural ventilation as hot air rises and drags cold air from below.

In an embodiment of the present invention the thermoelectric generator can be replaced by any type of heat to electric conversion technics, such as, but not limited to heat exchange systems using liquids with low boiling point.

In an embodiment of the present invention the power harvesting device further comprises a laser diode power controller for regulating the power directed to the high-power pump laser diode.

In an embodiment of the present invention a power regulation unit communicates with the control and supervising section and/or the laser diode power controller for dynamically including and/or excluding current transformer units from high-power pump laser diode based on required electrical power of the power conversion and supply device.

In In an embodiment of the present invention the mast structure module further comprises a power regulation unit for monitoring the operation of the laser power to heat conversion unit and the thermoelectric generator unit, such as, but not limited to currents, voltages and heat and for controlling charging and discharging of the power storage means.

In an embodiment of the present invention the power storage device can store electrical power to balance the irregularity in power generation and power demand. In an embodiment of the present invention the high-power pump laser diode transmits the high-power laser beam through fibres in the optical cable to the mast structure module.

In an embodiment of the present invention the apparatus further comprises a power supply unit.

In an embodiment of the present invention the power storage device is a supercapacitor or battery-based power storage device.

In an embodiment of the present invention the apparatus further comprises a power regulation unit.

In an embodiment of the present invention the power harvesting and transfer device and the power receiving and conversion device, each comprise a housing.

In an embodiment of the present invention the power harvesting and transfer device comprises a housing adapted to be mounted or clamped on the phase wire of high-voltage power line.

In an embodiment of the present invention the power supply device comprises a housing adapted to be mounted on the ground-based mast structure.

Description of various embodiments

The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:

FIG. 1 is an overview of the apparatus of the present invention.

FIG. 2 is a block diagram for the system of the invention.

FIG. 3 is a simplified drawing outlining the function of the laser to heat conversion unit and the thermoelectric generator unit.

FIG. 4 outlines the system of the invention.

FIG. 5 show three different laser to electricity conversion units.

FIG. 6 is diagram of a current transformer unit of the present invention.

FIG. 7 is a diagram of a power harvesting section for the apparatus of the invention employing six current transformer units. Figure 1 shows the apparatus of the present invention mounted on a phase wire of a high- voltage power line and a mast for carrying that high voltage power line. The figure shows a phase wire 1 carried by an electrically ground-based mast structure 2 with high-voltage insulator chains 3, a bridge 4 and a conductor loop 5 for passing the high voltage power line across the electrically ground-based mast structure.

The apparatus comprises a power harvesting device 10 mounted on a live phase wire 1 of a high-voltage power line. The power harvesting device 10 is connected to a power supplying device 20, which is attached to the electrically ground-based mast 2 carrying the phase wire 1, by an all-dielectric optical fibre cable 30.

Figure 2 shows a block diagram for a system according to an embodiment of the invention with thermoelectric power conversion of the laser beam. The power harvesting device is located on the high-voltage phase wire and the power supplying device is located on the electrically ground-based mast structure are connected across isolation boundaries by highly dielectric optical cable that secures safe transmitting of a high-power laser beam between the high-voltage side and the electrically ground-based side of the system. On the high-voltage side, the power harvesting device 10 is shown. The power harvesting is based on using one or more current transformer units which can convert the alternating current (AC) in a phase wire to a secondary winding alternating current. Each such secondary winding alternating current (AC) is then transformed to a direct current (DC) by a MOSFET based rectifier. By connecting all the rectifiers to a common load on their DC side, the generated direct current and their respective DC voltage are added together. On the DC side, DC voltage is generated and thus a DC power output. The power harvesting device provides DC power for a high-power pump laser diode 15, which then transmits the high-power laser beam through fibres in the optical cable 30 to a power supplying device 20 on the low-voltage side in the electrically ground-based mast structure. A laser to heat conversion unit 40 is provided in a heat isolated chamber and connected to the optical cable 30. The laser to heat conversion unit uses a scattering lens or lenses to distribute the high-power laser beam over a large area of a heat absorbing material. The heat absorbing material touching the hot side of the Peltier modules and the air ventilated heat sink material touching the cold side of the Peltier modules, create a heat difference across the two surfaces of the Peltier modules. The heat difference causes the Peltier modules to act as a thermoelectric generator unit 50, based on the Peltier effect, that generates unregulated DC power (voltage and current). The unregulated DC power output is directed into a power supply unit 60, which regulates the output from the thermoelectric generator unit 50 to and from the power storage device 70 and into the power regulation unit 80. The power regulation unit 80 monitors, controls and regulates the power generation of the power supplying device 20 through communication with the power supply unit 60 and the power storage device 70. Moreover, it communicates with the power harvesting device 10 to manage the operation of the whole system. Furthermore, the power regulation unit 80 can provide both DC and AC power output.

Figure 3 is a simplified drawing outlining the function of the laser to heat conversion unit 49 and the thermoelectric generator unit 50. The laser to heat conversion unit 49 is contained in a heat isolated chamber 55, which prevents possible heat losses into the environment. An optical fibre connector 35 provides inlet for the laser beam, which passes through a scattering lens or lenses 41 and distributes the laser beam 42 over large surface area of the heat absorbing material 51. On the other side of the heat absorbing material a, number of Peltier modules 52 are arranged and tightly pressed up against the heat absorbing material 51. This is to secure as much as possible that the heat generated by the laser beam and stored in the heat absorbing material 51 only passes through the Peltier modules 52. On the other side of the Peltier modules 52 a heat-sink 53, acts as a cooling material, and is tightly pressed against the Peltier modules 52. The drawing shows an array of Peltier modules between the heat absorbing material 51 and the cooling material 53. The Peltier modules generate electric power when exposed to heat on one side and cold on the other. The embodiment shown in Fig. 3 has a heat sink cooling on the "cold" side of the Peltier modules, which is based on the chimney effect, i.e. the effect of natural ventilation when hot air rises and drags cold air from below (indicated by block arrows). In a different embodiment of the thermoelectric generator the use of air-cooling fans or some type of liquid cooling technics may be applied.

Figure 4 shows an overview of the system and devices of the present invention. The figure shows the laser-based power supply system for transferring electric power from a phase wire of a high-voltage power line to a receiving device or any device which requires energy/electricity. The apparatus comprises a Power Harvesting Device 10 sitting on the high-voltage power line and is connected to a power supplying device 20 located in the electrically ground-based mast structure of that same power line, by an optical fibre cable 30. The power harvesting device 10 has a control and supervising section 11, a power harvesting section 12 and a high-power pump laser diode 15 for generating a laser beam from the harvested output power of the power harvesting device 10. The power supplying device 20 has laser to electricity conversion unit 40 comprising a scattering lens or an array of lenses 41 and mirrors for distributing the narrow metal cutting laser beam 42 onto an electric generating material or device. The laser to electricity conversion unit 40 has a electrical power output 54 connected to a power supply unit 60, which monitors, controls and regulates the power generation of the power supplying device 20. The power supplying device 20 further comprises a power storage device 70, and a power regulation unit 80, where the electrical power output from the laser to electricity conversion unit 40 is connected to the power supply unit 60. The power supply unit 60 further regulates charging of the power storage device 70. The power regulation unit 80 has a communication pathway through a separate optical fibre in the optical cable (30) to the control and supervising section of the power harvesting device 10, shown by a dotted line 13. A current controller or laser diode power controller 14 when adjusted will result in that the power harvesting section 12 will dynamically include or exclude current transformer units from the power output, but the laser diode power controller 14 can also connect or disconnect the high-power pump laser diode 15 fully from the power output of the power harvesting section 12.

Figure 5 discloses three different embodiments of a laser to electricity conversion unit 40. In Fig. 5A, a laser to heat conversion unit 49 and a thermoelectric generator unit 50 are used to convert laser power to electrical power. The scattering lens or an array of lenses 41 distribute a narrow metal cutting laser beam 42 over a large surface area of the heat absorbing material 51 of a thermoelectric generator unit 50. The laser to heat conversion unit 40 is contained in a heat isolated chamber 55 to prevent the heat generated therein to escape. The heat isolated chamber 55 has an opening for the optical fibre connector 35 and a larger opening or cut-out to fit in the Peltier modules 52 tightly close to the heat absorbing material. The thermoelectric generator unit 50 is made by arranging heat absorbing material 51, Peltier modules 52, and cooling material 53 in a sandwich manner together with a DC power output 54 as outlined in Fig 4. Power supplying device 20 further comprises a power supply unit 60, a power storage Device 70, and a power regulation unit 80 where the DC power output from the thermoelectric generator unit 50 is connected to the power supply unit 60 which then monitors, controls and regulates the power generation of the power supplying device 20. The power supply unit 60 also regulates the output from the thermoelectric generator unit 50 to a stable DC voltage level and at the same time charges the power storage device. In Figs. 5B and 5C, the laser to electricity conversion unit 40 is a photovoltaic conversion unit. The photovoltaic conversion unit shown in the embodiment of Fig 5B has a photovoltaic chamber with a scattering lens 41 for distributing the laser beam onto a mirror structure 43 of highly reflective mirrors arranged in a pyramid. Photovoltaic cells 44 are arranged on five walls inside the photovoltaic chamber with thermoelectric generating modules 45 arranged behind the photovoltaic cells 44. Heatsink units/heatsink material 46 is arranged to cover the outside wall of the photovoltaic chamber. The photovoltaic conversion unit has a photovoltaic electric output 47 as well as a thermoelectric output 48. The embodiment of Fig 5C has only photovoltaic cells 44, but no thermoelectric generating modules and the electrical output from the photovoltaic chamber is a photovoltaic electric output 47. Figure 6 outlines an embodiment of the power harvesting section of the device of the present invention for extracting power from electrical conductors 1 having one current transformer unit 120, which is not shunted. The current transformer unit comprises one core 121 configured to be located around a primary wire 1, one secondary winding 122 is arranged around the core 121. The secondary winding 122 has a first end and a second end, a rectifier 123 configured to convert an alternating current to a direct current, wherein the rectifier comprises two AC connections for alternating current and two DC connections for direct current, wherein the first end and the second end of the secondary winding 122 are connected to the AC connections of the rectifier 123 and a load 124 is connected to the DC connection of each rectifier 123. The load in the drawing is shown as a BURDEN component it the circuitry but is in fact the common load of components and auxiliary devices in the apparatus powered by the power harvesting section. The secondary winding 122 is connected to the rectifier 123 through a current shunt 125 arranged and configured to totally short circuit the ends of the secondary winding when needed. The power harvesting section further comprises a zero-crossing detection section 126, which is connected in series to the current transformer unit 120. A shunting unit 132 is configured to shunt the device circuit in such a way that no current runs through the rectifier to the load, i.e. total short circuiting shunting such that no voltage is generated across the rectification circuit (cold regulation). The current shunt 125 preferably comprises MOSFET- transistors which completely short circuits the secondary winding of the current transformer unit and thereby eliminates power losses and heat generation in power regulation circuit.

As the power harvesting section is used to power components of a surveillance device, such as the meteorological station of the present invention, on high voltage power line, the transformer core 121 is placed around the phase wire 1 to induce current in the secondary winding 122, which is wound around the core 121. The induced AC current is rectified from AC power to DC power and fed to the common DC load 124 of the DC power output, i.e. the devices powered by the power harvesting section, such as the control circuitry, sensors and communication devices. In case the voltage across the system becomes too high, the shunting unit 132 shunts the secondary winding of each individual current transformer unit 120 when needed, in the zero-crossing of the AC current detected by the zero-crossing detection 126. The shunting and rectification circuitry of the power harvesting section is shown in the lower part of the diagram of Fig. 6, where the zero crossing component 126 is connected in series to the current transformer unit 120. A DC voltage component 127 serves as a voltage level detection input for controlling operation of current shunts 125 and is configured along with state latch 128 to dynamically turn the current shunts 125 on and off when needed. An optically isolated MOSFET driver 129 along with blocking transistor pair of the current shunts 125 provide the shunting mechanism and both the optically isolated MOSFET driver 129 and the current shunt 125 preferably comprise MOSFET transistors.

Figure 7 shows an embodiment of a power harvesting section with six current transformer units 120a - 120f for a combined inductive power extraction from an AC power line. One secondary winding 122a has the zero-crossing component circuitry connected to it, but otherwise is not different from the additional secondary windings 120b-f. All of the secondary windings 122, share a single common DC load 124, since it is placed on the DC side of the circuit. Each secondary winding 122, 122a comprises its own shunting unit 132 (depicted in the figure as the current shunt 125 and the optically isolated MOSFET driver 129), so that each of the windings can be dynamically and independently shunted when needed and therefore totally short circuited for precise regulation of overall power extraction. That is, each secondary winding may comprise a current shunt 125 and a shunt controller unit 133 comprising state latch 128 and the optically isolated MOSFET driver 129. All of the secondary windings can also provide power for the basic electronic power regulation circuitry (i.e. the analog and control logic 131, the zero-crossing detection 126 etc.) and for any sensors or devices implemented as a part of the power extraction device. The DC sides of the rectifiers of the current transformer units are connected to the common DC load 124, such as the power inputs of the sensing and measuring devices to be powered. The DC outputs of the current transformer units are connected in parallel, therefore the DC outputs are added to one another. Thus, the overall summed DC power output at the common DC load 124, may be the sum of the (hypothetical) DC power outputs of each current transformer unit. Smoothing capacitors 130 have the purpose of smoothing the AC ripple in the DC power output.