Tesla transmits electricity wirelessly. Wireless power transmission
Everyone knows that Nikola Tesla is the inventor of such ubiquitous things as alternating current and the transformer. But not all scientists are familiar with Tesla's other inventions.
We use alternating current. We use transformers. In any apartment. It is difficult to imagine how one can do without these inventions. But HOW do we use them? Tesla used these things known to us (as it seems to us) in a completely different way. How do we connect any electrical appliance to the network? With a fork - i.e. two conductors. If we connect only one conductor, there will be no current - the circuit is not closed.
Tesla demonstrated the effect of transmitting power through a single conductor. Moreover, in other experiments it transmitted power without wires at all. At the end of the 19th century, the great inventor was able to transmit electrical energy wirelessly over a distance of over 40 kilometers. Since this well-known Tesla experiment has not yet been repeated, our readers will certainly be interested in the details of this story, as well as the current state of the problem of transmitting electrical energy without wires.
The biography of the American inventor, Serbian by birth, Nikola Tesla is quite well known, and we will not dwell on it. But let’s immediately clarify: before demonstrating his unique experiment, Tesla, first in 1892 in London, and a year later in Philadelphia, in the presence of specialists, demonstrated the possibility of transmitting electrical energy through one wire, without using grounding of the second pole of the energy source.
And then he had the idea to use the Earth as this only wire! And in the same year, at the Electric Lighting Association convention in St. Lewis, he demonstrated electric lamps that burned without wires and an electric motor operating without being connected to the electrical network. He commented on this unusual exhibition as follows: “A few words about an idea that constantly occupies my thoughts and concerns us all. I mean transmitting signals, as well as energy, over any distance without wires. We already know that electrical vibrations can be transmitted through a single conductor. Why not use the Earth for this purpose? If we can determine the period of oscillation electric charge Earth, with its disturbance associated with the action of an oppositely charged circuit, this will be a fact of extreme importance, which will serve for the benefit of all mankind.”
Seeing such a spectacular demonstration, such famous oligarchs as J. Westinghouse and J. P. Morgan invested over a million dollars in this promising business, buying his patents from Tesla (huge money, by the way, at that time!). With these funds, in the late 90s of the 19th century, Tesla built his unique laboratory in Colorado Springs. Detailed information about the experiments in Tesla’s laboratory is presented in the book of his biographer John O’Neill, “Electric Prometheus” (in our country, its translation was published in the magazine “Inventor and Innovator” No. 4-11 for 1979). We will give here only a brief excerpt from it, so as not to refer to later reprints: “In Colorado Springs, Tesla conducted the first tests of wireless transmission of electricity. He was able to power 200 incandescent light bulbs located 42 kilometers from his laboratory with the current drawn from the Earth during the operation of a giant vibrator. Each power was 50 watts, so the total energy consumption was 10 kW, or 13 hp. Tesla was convinced that with the help of a more powerful vibrator he could light a dozen electric garlands of 200 light bulbs each, scattered around the globe."
Tesla himself was so inspired by the success of these experiments that he announced in the general press that he intended to illuminate the World Industrial Exhibition in Paris, which was supposed to be held in 1903, with energy from a power plant located at Niagara Falls and transmitted to Paris wirelessly. It is known from numerous photographs and descriptions of eyewitnesses and assistants of the inventor that it was a generator of energy transmitted over 42 kilometers without wires (however, this is a purely journalistic term: one wire, which was the Earth, is present in this circuit, and this is directly stated both Tesla himself and his biographer).
What Tesla called a vibrator was a giant transformer of his system, which had a primary winding of several turns of thick wire wound on a fence with a diameter of 25 meters, and a multi-turn single-layer secondary winding placed inside it on a cylinder of dielectric. The primary winding, together with a capacitor, an induction coil and a spark gap, formed an oscillatory circuit-frequency converter. Above the transformer, located in the center of the laboratory, rose a wooden tower 60 meters high, topped with a large copper ball. One end of the secondary winding of the transformer was connected to this ball, the other was grounded. The entire device was powered by a separate 300 hp dynamo. Electromagnetic oscillations with a frequency of 150 kilohertz (wavelength 2000 meters) were excited in it. Operating voltage in the high-voltage circuit was 30,000 V, and the resonating potential of the ball reached 100,000,000 V, generating artificial lightning tens of meters long! This is how his biographer explains the work of Tesla’s vibrator: “In essence, Tesla “pumped” a stream of electrons into the Earth and extracted from there. The pumping frequency was 150 kHz. Spreading in concentric circles further and further from Colorado Springs, the electric waves then converged at a diametrically opposite point on the Earth. Large amplitude waves rose and fell there in unison with those raised in Colorado. When such a wave fell, it sent an electric echo back to Colorado, where an electric vibrator amplified the wave, and it rushed back.
If we bring the entire Earth into a state of electrical vibration, then at every point on its surface we will be provided with energy. It will be possible to capture it from the waves rushing between the electric poles simple devices similar to the oscillating circuits in radio receivers, only grounded and equipped with small antennas the height of a rural cottage. This energy will heat and light homes using Tesla's tubular lamps, which require no wires. For electric motors alternating current only frequency converters would be needed.”
Information about Tesla's experiments on transmitting electricity without wires inspired other researchers to work in this area. Reports of similar experiments often appeared in the press at the beginning of the last century. In this regard, it is worth citing an excerpt from an article by A.M. Gorky’s “Conversations on Craft,” published in 1930: “This year, Marconi transmitted electric current by air from Genoa to Australia and lit electric lamps there at an exhibition in Sydney. The same thing was done 27 years ago here, in Russia, by the writer and scientist M.M. Filippov, who worked for several years on transmitting electric current through the air and eventually lit a chandelier from St. Petersburg in Tsarskoe Selo ( that is, at a distance of 27 kilometers. -V.P.). At that time, no due attention was paid to this fact, but Filippov was found dead in his apartment a few days later, and his devices and papers were confiscated by the police.”
Tesla's experiments also made a great impression on another writer, Alexei Tolstoy, who was an engineer by training. And when Tesla, and then Marconi, reported in print that their devices were receiving strange signals of extraterrestrial, apparently Martian origin, this inspired the writer to write the science fiction novel “Aelita.” In the novel, the Martians use Tesla's invention and wirelessly transmit energy from power plants located at the poles of Mars to anywhere on the planet. This energy powers the engines of flying ships and other mechanisms. However, to build your own “world system” to provide electricity to the population globe Tesla failed without the use of wires.
As soon as in 1900 he began to build a research laboratory town for 2000 employees and a huge metal tower with a giant copper plate on top on the island of Long Island near New York, the “wired” electrical oligarchs realized it: after all, the widespread introduction of Tesla’s system threatened them with ruin.
Wardenclyffe Tower (1902)
On billionaire J.P. Morgan, who financed the construction, was subject to severe pressure, including from government officials bribed by competitors.(or it was the other way around) There were interruptions in the supply of equipment, construction stalled, and when Morgan, under this pressure, stopped funding, it stopped altogether. At the beginning of the First World War, at the instigation of the same competitors, the US government ordered the explosion of a ready-made tower under the far-fetched pretext that it could be used for espionage purposes.
Well, then electrical engineering went the usual way.
For a long time no one could repeat Tesla’s experiments, if only because it would have been necessary to create an installation similar in size and power. But no one doubted that Tesla managed to find a way to transmit electrical energy over a distance without wires more than a hundred years ago. The authority of Tesla, who was rated as the second inventor after Edison, was quite high throughout the world, and his contribution to the development of alternating current electrical engineering (in defiance of Edison, who advocated D.C.) is certain. During his experiments, many specialists were present, not counting the press, and no one ever tried to convict him of any tricks or manipulation of facts. The high authority of Tesla is evidenced by the name of the unit of tension after him. magnetic field. But Tesla’s conclusion that during the experiment in Colorado Springs energy was transmitted over a distance of 42 kilometers with an efficiency of about 90% is too optimistic. Let us recall that the total power of the lamps lit at a distance was 10 kW, or 13 hp, while the power of the dynamo that powered the vibrator reached 300 hp. That is, we can talk about efficiency. only about 4-5%, although this figure is amazing. The physical justification of Tesla's experiments on wireless transmission of electricity still worries many specialists.
www.elec.ru/news/2003/03/14/1047627665.h tml
Specialists from the Massachusetts Institute of Technology managed to make an incandescent lamp burn, located at a distance of 2 meters from the energy source. rus.newsru.ua/world/08jun2007/tesla.html
Wireless chargers from Intel odessabuy.com/news/item-402.html
"Arguments and Facts" No. 52, 2008 (December 24-30):
SCIENCE - Electricity without wires. They say that American scientists were able to transmit electricity with a power of 800 W without wires.
Discovered a law (later named Ampere's law after its discoverer), showing that electric current produces a magnetic field.
- IN 2007 In 2009, a research team led by Professor Marin Soljačić wirelessly transmitted over a distance of 2 m energy sufficient to light a 60-watt light bulb with an efficiency of 40% using two coils with a diameter of 60 cm.
- IN 2008 In 2009, Bombardier proposed a system for wireless power transmission, called "primove" and intended for use in trams and light-duty engines. railway.
- IN 2008 In 2009, Intel employees reproduced the experiments of Nikola Tesla in 1894 and the experiments of John Brown's group in 1988 on wireless energy transfer to light incandescent lamps with an efficiency of 75%.
- IN 2009 In 2009, a consortium of interested companies called the Wireless Power Consortium developed a low-current wireless power standard called "". Qi has begun to be used in portable technology.
- IN 2009 In 2018, the Norwegian company Wireless Power & Communication presented an industrial flashlight it had developed that could operate safely and be recharged without contact in an atmosphere saturated with flammable gas.
- IN 2009 In 2018, Haier Group introduced the world's first fully wireless LCD TV, based on Professor Marin Soljačić's research on wireless power transmission and Wireless Home Digital Interface (WHDI).
- IN 2011 This year, the Wireless Power Consortium began expanding the specifications of the Qi standard for medium currents.
- IN 2012 In 2006, the private St. Petersburg museum “Grand Model Russia” began operating, in which miniature car models received wireless power through a model road surface.
- IN 2015 This year, scientists from the University of Washington discovered that electricity can be transmitted via Wi-Fi technology.
Technologies
Ultrasonic method
An ultrasonic method of energy transfer was invented by students at the University of Pennsylvania and first presented to the general public at the exhibition “The All Things Digital” (D9) in 2011. As with other methods of transmitting something wirelessly, a receiver and a transmitter were used. The transmitter emitted ultrasound; the receiver, in turn, converted what was heard into electricity. At the time of presentation, the transmission distance reached 7-10 meters, and direct visibility of the receiver and transmitter was necessary. The transmitted voltage reached 8 volts; the resulting current is not reported. The ultrasonic frequencies used have no effect on humans. There is also no information about the negative effects of ultrasonic frequencies on animals.
Electromagnetic induction method
Wireless energy transfer by electromagnetic induction uses a near-field electromagnetic field at distances of about one-sixth of a wavelength. Near-field energy itself is not radiative, but some radiative losses do occur. In addition, as a rule, resistive losses also occur. Thanks to electrodynamic induction, an alternating electric current flowing through the primary winding creates an alternating magnetic field, which acts on the secondary winding, inducing an electric current in it. To achieve high efficiency, the interaction must be quite close. As the secondary winding moves away from the primary, more and more of the magnetic field does not reach the secondary winding. Even over relatively short distances, inductive coupling becomes extremely inefficient, wasting most of the transmitted energy.
An electrical transformer is the simplest device for wireless energy transfer. The primary and secondary windings of the transformer are not directly connected. Energy transfer occurs through a process known as mutual induction. The main function of a transformer is to increase or decrease the primary voltage. Contactless chargers for mobile phones and electric toothbrushes are examples of the use of the principle of electrodynamic induction. Induction cookers also use this method. The main disadvantage of the wireless transmission method is its extremely short range. The receiver must be in close proximity to the transmitter in order to communicate with it effectively.
The use of resonance slightly increases the transmission range. With resonant induction, the transmitter and receiver are tuned to the same frequency. Performance can be improved further by changing the control current waveform from sinusoidal to non-sinusoidal transient waveforms. Pulsed energy transfer occurs over several cycles. In this way, significant power can be transferred between two mutually tuned LC circuits with a relatively low coupling coefficient. The transmitting and receiving coils, as a rule, are single-layer solenoids or a flat spiral with a set of capacitors that allow the receiving element to be tuned to the frequency of the transmitter.
A common application of resonant electrodynamic induction is to charge the batteries of portable devices, such as laptop computers and cell phones, medical implants, and electric vehicles. The localized charging technique uses the selection of an appropriate transfer coil in a multilayer winding array structure. Resonance is used in both the wireless charging panel (transmitting circuit) and the receiver module (built into the load) to ensure maximum power transfer efficiency. This transmission technique is suitable for universal wireless charging pads for recharging portable electronics such as mobile phones. The technique has been adopted as part of the Qi wireless charging standard.
Resonant electrodynamic induction is also used to power devices that do not have batteries, such as RFID tags and contactless smart cards, as well as to transfer electrical energy from the primary inductor to the helical resonator of the Tesla transformer, which is also a wireless transmitter of electrical energy.
Electrostatic induction
Laser method
If the wavelength electromagnetic radiation approaches the visible region of the spectrum (from 10 µm to 10 nm), energy can be transferred by converting it into a laser beam, which can then be directed to a photocell of the receiver.
Laser energy transmission has a number of advantages compared to other wireless transmission methods:
- energy transfer over long distances (due to the small divergence angle between narrow beams of a monochromatic light wave);
- ease of use for small products (due to the small size of the solid-state laser - photoelectric semiconductor diode);
- absence of radio frequency interference for existing communications devices, such as Wi-Fi and cell phones (laser does not create such interference);
- possibility of access control (only receivers illuminated by a laser beam can receive electricity).
U this method There are also a number of disadvantages:
- Converting low-frequency electromagnetic radiation into high-frequency radiation, which is light, is ineffective. Converting light back into electricity is also inefficient, since the efficiency of solar cells reaches 40-50%, although the efficiency of converting monochromatic light is much higher than the efficiency of solar panels;
- losses in the atmosphere;
- the need for line of sight between the transmitter and receiver (as with microwave transmission).
Laser power transfer technology has previously been primarily explored in the development of new weapons systems and in the aerospace industry, and is currently being developed for commercial and consumer electronics applications in low power applications. Wireless power transmission systems for consumer applications must meet the laser safety requirements of IEC 60825. To better understand laser systems, it should be taken into account that laser beam propagation is much less dependent on diffraction limitations, as spatial and spectral matching of laser characteristics allows increase operating power and distance as wavelength affects focusing.
NASA's Dryden Flight Research Center demonstrated the flight of a light unmanned model aircraft powered by a laser beam. This proved the possibility of periodic recharging via a laser system without the need to land the aircraft.
Alternating current can be transmitted through layers of the atmosphere that have Atmosphere pressure less than 135 mm Hg. Art. Current flows through electrostatic induction through the lower atmosphere at approximately 2-3 miles (3.2-4.8 kilometers) above sea level and due to the flow of ions, i.e. electrical conductivity through an ionized region located at an altitude above 5 km. Intense vertical beams ultraviolet radiation can be used to ionize atmospheric gases directly above the two elevated terminals, resulting in the formation of plasma high-voltage power lines leading directly to the conductive layers of the atmosphere. As a result, a flow of electric current is formed between the two elevated terminals, passing to the troposphere, through it and back to the other terminal. Electrical conductivity through the layers of the atmosphere is made possible by a capacitive plasma discharge in an ionized atmosphere.
Nikola Tesla discovered that electricity can be transmitted both through the earth and through the atmosphere. In the course of his research, he achieved the ignition of a lamp at moderate distances and recorded the transmission of electricity over long distances. The Wardenclyffe Tower was conceived as a commercial project for transatlantic wireless telephony and became a real demonstration of the possibility of wireless power transmission on a global scale. The installation was not completed due to insufficient funding.
The earth is a natural conductor and forms one conductive circuit. The return loop occurs through the upper troposphere and lower stratosphere at an altitude of about 4.5 miles (7.2 km).
Global system transmission of electricity without wires, the so-called “Worldwide Wireless System”, based on the high electrical conductivity of plasma and the high electrical conductivity of the earth, was proposed by Nikola Tesla in early 1904 and could well have been the cause of the Tunguska meteorite that arose as a result of “ short circuit“between the charged atmosphere and the ground.
Worldwide Wireless System
The early experiments of the famous Serbian inventor Nikola Tesla concerned the propagation of ordinary radio waves, that is, Hertzian waves, electromagnetic waves propagating in space.
In 1919, Nikola Tesla wrote: “It is believed that I began work on wireless transmission in 1893, but in fact I had been conducting research and constructing equipment for the previous two years. It was clear to me from the very beginning that success can be achieved through a number of radical solutions. High frequency generators and electrical oscillators had to be created first. Their energy had to be converted into efficient transmitters and received at a distance by suitable receivers. Such a system would be effective if it excluded any outside interference and ensured its complete exclusivity. Over time, however, I realized that for devices of this kind to work effectively, they must be designed taking into account the physical properties of our planet."
One of the conditions for creating a global wireless system is the construction of resonant receivers. A Tesla coil's grounded helical resonator and elevated terminal can be used as such. Tesla personally repeatedly demonstrated the wireless transmission of electrical energy from the transmitting to the receiving Tesla coil. This became part of his wireless transmission system (U.S. Patent No. 1119732, January 18, 1902, "Apparatus for Transmitting Electrical Energy"). Tesla proposed installing more than thirty transceiver stations around the world. In this system, the take-up coil acts as a step-down transformer with a high current output. The parameters of the transmitting coil are identical to the receiving coil.
The goal of Tesla's worldwide wireless system was to combine power transmission with radio broadcasting and directional wireless communications, which would eliminate the need for numerous high-voltage power lines and facilitate the interconnection of electrical generators on a global scale.
see also
- WiTricity
Notes
- "Electricity at the Columbian Exposition", by John Patrick Barrett. 1894, pp. 168-169 (English)
- Experiments with Alternating Currents of Very High Frequency and Their Application to Methods of Artificial Illumination, AIEE, Columbia College, N.Y., May 20, 1891 (English)
- Experiments with Alternate Currents of High Potential and High Frequency, IEE Address, London, February 1892
- On Light and Other High Frequency Phenomena, Franklin Institute, Philadelphia, February 1893 and National Electric Light Association, St.
- Louis, March 1893
- The Work of Jagdish Chandra Bose: 100 years of mm-wave research (English)
- Jagadish Chandra Bose (English)
- Nikola Tesla On His Work With Alternating Currents and Their Application to Wireless Telegraphy, Telephony and Transmission of Power, pp. 26-29. (English) June 5, 1899, Nikola Tesla Colorado Spring Notes
- 1899-1900, Nolit, 1978 (English)
- Nikola Tesla: Guided Weapons & Computer Technology (English) The Electrician
- (London), 1904 (English)
- Scanning the Past: A History of Electrical Engineering from the Past, Hidetsugu Yagi Tetelbaum S. I.
- On wireless transmission of electricity over long distances using radio waves // Electricity. - 1945. - No. 5. - pp. 43-46. Kostenko A. A.
- Quasi-optics: historical background and modern development trends // Radiophysics and radio astronomy. - 2000. - T. 5, No. 3. - P. 231.
- A survey of the elements of power Transmission by microwave beam, in 1961 IRE Int.
- Conf.
- Rec., vol.9, part 3, pp.93-105 (English)
- IEEE Microwave Theory and Techniques, Bill Brown's Distinguished Career (English)
- Power from the Sun: Its Future, Science Vol. 162, pp. 957-961 (1968)
- Solar Power Satellite patent (English)
- History of RFID
- Space Solar Energy Initiative(English) . Science (7 June 2007). Retrieved September 6, 2010. Archived February 29, 2012.,
A new way of wirelessly transmitting electricity has launched (Russian). MEMBRANA.RU (June 8, 2007). Retrieved September 6, 2010. Archived February 29, 2012. - Bombardier PRIMOVE Technology
- Intel imagines wireless power for your laptop (English)
- wireless electricity specification nearing completion
- Global Qi Standard Powers Up Wireless Charging - HONG KONG, Sept.
- 2 /PRNewswire/
- TX40 and CX40, Ex approved Torch and Charger
Haier's wireless HDTV lacks wires, svelte profile (video) (English) , (Russian) Wireless electricity amazed its creators
. MEMBRANA.RU (February 16, 2010). Retrieved September 6, 2010.
If history is to be believed, the revolutionary technological project was frozen due to Tesla’s lack of adequate financial resources (this problem haunted the scientist almost all the time he worked in America). Generally speaking, the main pressure on him came from another inventor, Thomas Edison and his companies, who were promoting direct current technology while Tesla was working on alternating current (the so-called “War of the Currents”). History has put everything in its place: now alternating current is used in city power grids almost everywhere, although echoes of the past continue to this day (for example, one of the stated reasons for breakdowns of the notorious Hyundai trains is the use of direct current power lines in some sections of the Ukrainian railway).
Wardenclyffe Tower, where Nikola Tesla conducted his experiments with electricity (photo from 1094)
As for Wardenclyffe Tower, according to legend, Tesla demonstrated to one of the main investors J.P. Morgan, a shareholder of the world's first Niagara hydroelectric power station and copper plants (copper, as you know, is used in wires), a working installation for wireless current transmission, the cost of which for consumers would be (if such installations were built on an industrial scale) an order of magnitude cheaper for consumers, after why he stopped financing the project. Be that as it may, they started talking seriously about wireless power transmission only 90 years later, in 2007. And while it's still a long way off before power lines completely disappear from the cityscape, nice little things like wireless charging for your mobile device are available now.
If we look through the archives of IT news from at least two years ago, then in such collections we will find only rare reports that certain companies are developing wireless chargers, and not a word about finished products and solutions (except for the basic principles and general schemes). Today, wireless charging is no longer something super-original or conceptual. Such devices are being sold with all their might (for example, LG demonstrated its chargers at MWC 2013), are being tested for electric vehicles (Qualcomm is doing this) and are even used in public places (for example, at some European railway stations). Moreover, several standards for such power transmission already exist and several alliances promote and develop them.
For wireless charging mobile devices similar coils respond, one of which is located in the phone, and the other in the charger itself
The most famous such standard is the Qi standard, developed by the Wireless Power Consortium, which includes such well-known companies as HTC, Huawei, LG Electronics, Motorola Mobility, Nokia, Samsung, Sony and about a hundred other organizations. This consortium was organized in 2008 with the goal of creating a universal charger for devices various manufacturers And brands. In its work, the standard uses the principle of magnetic induction, when base station consists of an induction coil that creates an electromagnetic field when alternating current is supplied from the network. The device being charged contains a similar coil that reacts to this field and is able to convert the energy received through it into direct current, which is used to charge the battery (you can learn more about the operating principle on the consortium website http://www.wirelesspowerconsortium.com/what -we-do/how-it-works/). In addition, Qi supports a data transfer protocol between chargers and charging devices at a speed of 2 kbps, which is used to transmit data about the required charging amount and the required operation.
Today, many smartphones support wireless charging using the Qi standard, and chargers are universal for all devices that support this standard.
Qi also has a serious competitor - the Power Matters Alliance, which includes AT&T, Duracell, Starbucks, PowerKiss and Powermat Technologies. These names are far from being at the forefront in the world information technologies(especially the Starbucks coffee chain, which is in an alliance because it is going to introduce it everywhere in its establishments this technology), - they specialize specifically in energy issues. This alliance was formed not so long ago, in March 2012, as part of one of the IEEE (Institute of Electrical and Electronics Engineers) programs. The PMA standard they promote works on the principle of mutual induction - a particular example of electromagnetic induction (which should not be confused with the magnetic induction used by Qi), when when the current in one of the conductors changes or when the relative position of the conductors changes, the magnetic flux through the circuit of the second one changes. magnetic field generated by the current in the first conductor, which causes the occurrence electromotive force in the second conductor and (if the second conductor is closed) induced current. Just as with Qi, this current is then converted to direct current and fed into the battery.
Well, don’t forget about the Alliance for Wireless Power, which includes Samsung, Qualcomm, Ever Win Industries, Gill Industries, Peiker Acustic, SK Telecom, SanDisk, etc. This organization has not yet presented ready-made solutions, but among its goals, among other things, is the development of charges that would work through non-metallic surfaces and that would not use coils.
One of the goals of the Alliance for Wireless Power is the ability to charge without being tied to a specific location or type of surface.
From all of the above, we can draw a simple conclusion: after a year or two, the majority modern devices will be able to recharge without using traditional chargers. For now, the wireless charging power is sufficient mainly for smartphones, but such devices will also appear soon for tablets and laptops (Apple recently patented wireless charging for the iPad). This means that the problem of device discharge will be solved almost completely - put or put the device in specific place, and even during operation it charges (or, depending on the power, discharges much more slowly). Over time, there is no doubt that their range of action will expand (now it is necessary to use a special mat or stand on which the device lies, or it must be very close), and they will be universally installed in cars, trains and even, possibly, airplanes.
Well, one more conclusion - most likely, it will not be possible to avoid another format war between different standards and the alliances promoting them.
Will we get rid of wires?
Wireless charging of devices is, of course, a good thing. But the powers that arise with it are sufficient only for the stated purposes. With the help of these technologies, it is still impossible to even illuminate a house, let alone operate large household appliances. Nevertheless, experiments on high-power wireless transmission of electricity are underway and they are based, among other things, on Tesla’s materials. The scientist himself proposed installing around the world (here, most likely, developed countries at that time were meant, of which there were much fewer than now) more than 30 receiving and transmitting stations that would combine energy transmission with radio broadcasting and directional wireless communications, which would allow get rid of numerous high-voltage power lines and facilitated the consolidation of electrical generation on a global scale.
Today there are several methods for solving the problem of wireless energy transfer, however, all of them so far allow achieving results that are insignificant in global terms; We're not even talking about kilometers. Methods such as ultrasonic, laser and electromagnetic transmission have significant limitations (short distances, the need for direct visibility of transmitting devices, their size, and in the case of electromagnetic waves, very low efficiency and harm to health from a powerful field). Therefore, the most promising developments involve the use of a magnetic field, or more precisely, resonant magnetic interaction. One of them is WiTricity, developed by the WiTricity corporation, founded by MIT professor Marin Soljacic and a number of his colleagues.
So, in 2007, they managed to transmit a current of 60 W over a distance of 2 m. It was enough to light a light bulb, and the efficiency was 40%. But the undeniable advantage of the technology used was that it practically does not interact with living beings (the field strength, according to the authors, is 10 thousand times weaker than what reigns in the core of a magnetic resonance imaging scanner) or with medical equipment ( pacemakers, etc.), nor with other radiation, which means it will not interfere, for example, with the operation of the same Wi-Fi.
What’s most interesting is that the efficiency of the WiTricity system is affected not only by the size, geometry and configuration of the coils, as well as the distance between them, but also by the number of consumers, and in a positive way. Two receiving devices placed at a distance of 1.6 to 2.7 m on either side of the transmitting “antenna” showed 10% better efficiency than individually - this solves the problem of connecting many devices to one power source.
Regularly looking through foreign achievements in the field of radio engineering, I came across a good device for wireless power transmission, made not on some scarce microcircuits, but quite accessible for self-assembly. Full documentation in English can be downloaded from the link, and here I will provide summary in Russian, including some circuit solutions.
Current transceiver coils
Signal oscillogram
The work presents several similar circuit diagrams, differing only in voltage and power. They use small coils of thick wire as an energy “antenna”; the transistors are ordinary powerful field-effect ones, so you can assemble all this yourself.
Let us warn you right away - here we are not talking about transmitting energy over many meters; such devices are more suitable for other similar devices, where the distance is several centimeters. But the power that “flies” through the air reaches up to 100 watts!
Operating principle
A resonant converter usually operates at a constant operating frequency, which is determined by resonant frequency LC circuit. Once DC voltage is applied to the circuit, it starts generating with the help of transistors. A kind of multivibrator, with a phase shift of 180°. Transistors alternately connect the ends of a parallel resonant circuit to the mass, which allows this circuit to periodically recharge with energy and then radiate it into space.
Practical schemes
Basic scheme
Photo of the finished energy transmitter-receiver
To summarize, we note that wireless power transmission is increasingly being implemented in the field of consumer electronics, industrial, military and medical equipment. Like wireless the local network Bluetooth and wireless power are becoming a popular option. This allows you to get rid of unreliable buttons, cables, and power connectors. Another area of application relates to transformers, which must meet special requirements such as reinforced or double insulation. And most importantly: electrical safety! Many low-power network Appliances can be powered not through 220 V cords, plugs and sockets, but using a non-contact method - simply by moving them to the desired surface.
In 1968, American space research specialist Peter E. Glaser proposed placing large panels solar panels in geostationary orbit, and the energy they generate (5-10 GW level) is transmitted to the surface of the Earth with a well-focused beam of microwave radiation, then converted into direct or alternating current energy of a technical frequency and distributed to consumers.
This scheme made it possible to use the intense flux of solar radiation existing in geostationary orbit (~ 1.4 kW/sq.m.) and transmit the resulting energy to the Earth's surface continuously, regardless of the time of day and weather conditions. Due to the natural inclination of the equatorial plane to the ecliptic plane with an angle of 23.5 degrees, a satellite located in a geostationary orbit is illuminated by the flow of solar radiation almost continuously, with the exception of short periods of time near the days of the spring and autumn equinoxes, when this satellite falls into the Earth's shadow. These periods of time can be accurately predicted, and in total they do not exceed 1% of the total length of the year.
The frequency of electromagnetic oscillations of the microwave beam must correspond to those ranges that are allocated for use in industry, scientific research and medicine. If this frequency is chosen to be 2.45 GHz, then meteorological conditions, including thick clouds and intense precipitation, have virtually no effect on the efficiency of power transmission. The 5.8 GHz band is attractive because it offers the opportunity to reduce the size of the transmit and receive antennas. However, the influence of meteorological conditions here requires additional study.
The current level of development of microwave electronics allows us to speak about a fairly high efficiency of energy transfer by a microwave beam with geostationary orbit to the Earth's surface - about 70-75%. In this case, the diameter of the transmitting antenna is usually chosen to be 1 km, and the ground rectenna has dimensions of 10 km x 13 km for a latitude of 35 degrees. A SCES with an output power level of 5 GW has a radiated power density at the center of the transmitting antenna of 23 kW/sq.m., and at the center of the receiving antenna – 230 W/sq.m.
Various types of solid-state and vacuum microwave generators for the SKES transmitting antenna were investigated. William Brown showed, in particular, that magnetrons, well developed by industry, intended for microwave ovens, can also be used in SKES transmitting antenna arrays, if each of them is equipped with its own negative circuit feedback in phase with respect to the external clock signal (the so-called Magnetron Directional Amplifier - MDA).
The most active and systematic research in the field of SCES was carried out by Japan. In 1981, under the leadership of Professors M. Nagatomo and S. Sasaki at the Space Research Institute of Japan, research began on the development of a prototype SCES with a power level of 10 MW, which could be created using existing launch vehicles. The creation of such a prototype allows one to accumulate technological experience and prepare the basis for the formation of commercial systems.
The project was named SKES2000 (SPS2000) and received recognition in many countries around the world.
In 2008, Marin Soljačić, assistant professor of physics at the Massachusetts Institute of Technology (MIT), was awakened from a sweet sleep by the persistent beeping of his cell phone. “The phone didn’t stop talking, demanding that I put it on charge,” Soljacic says. Tired and not about to get up, he began to dream that the phone, once at home, would start charging on its own.
In 2012-2015 Engineers at the University of Washington have developed technology that allows Wi-Fi to be used as an energy source to power portable devices and charge gadgets. The technology has already been recognized by Popular Science magazine as one of the best innovations of 2015. The ubiquity of wireless data transmission technology in itself has produced a real revolution. And now it’s the turn of wireless energy transmission over the air, which developers from the University of Washington called PoWiFi (from Power Over WiFi).
During the testing phase, the researchers were able to successfully charge small-capacity lithium-ion and nickel-metal hydride batteries. Using Asus router RT-AC68U and several sensors located at a distance of 8.5 meters from it. These sensors convert the energy of the electromagnetic wave into direct current with a voltage of 1.8 to 2.4 volts, which is necessary to power microcontrollers and sensor systems. The peculiarity of the technology is that the quality of the working signal does not deteriorate. You just need to reflash the router, and you can use it as usual, plus supply power to low-power devices. In one demonstration, a small camera was successfully powered covert surveillance with low resolution, located at a distance of more than 5 meters from the router. Then the Jawbone Up24 fitness tracker was charged to 41%, which took 2.5 hours.
To tricky questions about why these processes do not negatively affect the quality of the network communication channel, the developers answered that this becomes possible due to the fact that the re-flashed router, during its operation, sends energy packets through channels unoccupied by information transmission. They came to this decision when they discovered that during periods of silence, energy simply flows out of the system, but it can be used to power low-power devices.
During the research, the PoWiFi system was placed in six houses, and residents were asked to use the Internet as usual. Load web pages, watch streaming videos, and then tell us what's changed. As a result, it turned out that network performance did not change at all. That is, the Internet worked as usual, and the presence of the added option was not noticeable. And these were only the first tests, when a relatively small amount of energy was collected over Wi-Fi.
In the future, PoWiFi technology could well serve to power sensors built into household appliances and military equipment to control them wirelessly and perform remote charging/recharging.
Current is the transfer of energy for UAVs (most likely using PoWiMax technology or from the radar of the carrier aircraft): 
For a UAV, the negative from the inverse square law (isotropically radiating antenna) is partially “compensated” by the antenna beamwidth and radiation pattern:
After all, an aircraft's radar can produce 17 kW of EMP energy in a pulse.
This is not cellular communication - where the cell must provide 360-degree communication to the end elements.
Let's assume this variation:
The carrier aircraft (for Perdix) this F-18 has (now) AN/APG-65 radar: 
maximum average radiated power of 12000 W
Or in the future it will have AN/APG-79 AESA: 
in a pulse it should produce 15 kW of EMP energy
This is quite enough to extend the active life of Perdix Micro-Drones from the current 20 minutes to an hour, and maybe more.
Most likely, an intermediate Perdix Middle drone will be used, which will be irradiated at a sufficient distance by the fighter’s radar, and it, in turn, will “distribute” energy to the younger brothers of the Perdix Micro-Drones via PoWiFi/PoWiMax, while simultaneously exchanging information with them (flight, aerobatic, targets, swarm coordination).
Perhaps soon it will come to charging cell phones and other mobile devices that are within the range of Wi-Fi, Wi-Max or 5G?
Afterword: 10-20 years, after widespread implementation in daily life numerous electromagnetic microwave emitters (Mobile phones, Microwave ovens, Computers, WiFi, Blu tools, etc.) suddenly cockroaches in big cities suddenly turned into a rarity! Now the cockroach is an insect that can only be found in a zoo. They suddenly disappeared from the homes they once loved so much. 
COCKROACHES CARL!
These monsters, leaders of the list of “radioresistant organisms,” shamelessly capitulated!
Reference
LD 50 is the average lethal dose, that is, the dose kills half of the organisms in the experiment; LD 100 - lethal dose kills all organisms in the experiment.
Who's next in line?
Permissible radiation levels from base stations mobile communications(900 and 1800 MHz, total level from all sources) in sanitary and residential areas in some countries differ markedly:
Ukraine: 2.5 µW/cm². (the strictest sanitary standard in Europe)
Russia, Hungary: 10 µW/cm².
Moscow: 2.0 µW/cm². (the norm existed until the end of 2009)
USA, Scandinavian countries: 100 µW/cm².
Temporary permissible level (TAL) from mobile radiotelephones(MRI) for radiotelephone users in the Russian Federation, 10 μW/cm² is determined (Section IV - Hygienic requirements for mobile land radio communication stations SanPiN 2.1.8/2.2.4.1190-03 “Hygienic requirements for the placement and operation of land mobile radio communication equipment”).
In the USA, the Certificate is issued by the Federal Communications Commission (FCC) for cellular devices, maximum level SAR of which does not exceed 1.6 W/kg (and the absorbed radiation power is reduced to 1 gram of human organ tissue).
In Europe, according to the international directive of the Commission on Non-Ionizing Radiation Protection (ICNIRP), the SAR value of a mobile phone should not exceed 2 W/kg (the absorbed radiation power is reduced to 10 grams of human organ tissue).
More recently, in the UK, a safe SAR level was considered to be 10 W/kg. A similar picture was observed in other countries.
The maximum SAR value adopted in the standard (1.6 W/kg) cannot even be confidently attributed to “hard” or “soft” standards.
The standards adopted in both the USA and Europe for determining the value of SAR (all regulation of microwave radiation from cell phones, which is discussed, is based only on the thermal effect, that is, associated with heating the tissues of human organs).
COMPLETE CHAOS.
Medicine has not yet given a clear answer to the question: is mobile/WiFi harmful and to what extent?
What will happen to the wireless transmission of electricity using microwave technologies?
Here the power is not watts and miles of watts, but kW...
Note: A typical WiMAX base station emits power at approximately +43 dBm (20 W), and a mobile station typically transmits at +23 dBm (200 mW).
Tags:
- Electricity
- Microwave
- PoWiFi
- drones
- UAV