Electricity at a distance without wires. Making wireless power transmission

Since the discovery of electricity by man, many scientists have been trying to study the amazing phenomenon of currents and increase the useful coefficient of action by conducting numerous experiments and inventing more modern materials that have improved properties for transmitting energy with zero resistance. The most promising direction in such scientific work is the wireless transmission of electricity over long distances and with minimal transportation costs. This article discusses ways to transfer energy over a distance, as well as types of devices for such actions.

Wireless power transmission is a method of transportation that does not use any conductors or networks of cables, and the current is transmitted over a considerable distance to the consumer with the maximum effective power factor over the air. For this, devices for generating electricity are used, as well as a transmitter that accumulates current in itself and dissipates it in all directions, as well as a receiver with a consumer device. The receiver captures electromagnetic waves and fields and, by concentrating them on a short section of the conductor, transmits energy to a lamp or any other device of a certain power.

There are many ways for the wireless transmission of electricity, which were invented in the process of studying currents by many scientists, but Nikola Tesla achieved the greatest results in practical terms. He managed to make a transmitter and receiver, which were separated from each other by a distance equal to 48 kilometers. But at that time there were no technologies that could transmit electricity over such a distance with a coefficient higher than 50%. In this regard, the scientist expressed a great prospect not for the transfer of ready generated energy, but for generating current from the earth's magnetic field and using it for domestic needs. The transportation of such electricity had to be carried out wirelessly, by transmission through magnetic fields.

Methods for wireless transmission of electricity

Most theorists and practitioners who study the operation of electric current have proposed their own methods for transmitting it over a distance without the use of conductors. At the beginning of such studies, many scientists tried to borrow practice from the principle of operation of radio receivers, which are used to transmit Morse code or shortwave radio. But such technologies did not justify themselves, since the current dissipation was too small and could not cover long distances, moreover, the transportation of electricity via radio waves was possible only when working with low powers that could not drive even the simplest mechanism.

As a result of the experiments, it was found that microwave waves are most suitable for transmitting electricity without a wire, which have a more stable configuration and voltage, and also lose much less energy during dissipation than any other method.

For the first time, this method was successfully applied by the inventor and designer William Brown, who modeled a flying platform consisting of a metal platform with an engine with a power of about 0.1 horsepower. The platform was made in the form of a receiving antenna with a grid that captures microwave waves that were transmitted by a specially designed generator. After only fourteen years, the same designer presented a low-power aircraft that received energy from a transmitter at a distance of 1.6 kilometers, the current was transmitted in a concentrated beam through microwave waves. Unfortunately, this work was not widely used, since at that time there were no technologies that could ensure the transportation of high voltage current by this method, although the efficiency of the receiver and generator was more than 80%.

In 1968, American scientists developed a project, supported by scientific work, which proposed the placement of large solar arrays in low Earth orbit. Energy receivers had to be directed at the sun, and current storage devices were placed at their base. After absorbing solar radiation and transforming it into microwave or magnetic waves, the current was directed to the ground through a special device. Reception had to be carried out by a special large-area antenna, tuned to a certain wave and converting the waves into direct or alternating current. Such a system has been highly appreciated in many countries as a promising alternative to modern sources of electricity.

Powering an electric car wirelessly

Many manufacturers of electric vehicles are developing alternative recharging of a car without connecting it to the network. Great success in this area has been achieved by the technology of charging vehicles from a special roadbed, when the car received energy from a coating charged with a magnetic field or microwave waves. But such recharge was possible only if the distance between the road and the receiving device was no more than 15 centimeters, which is not always feasible in modern conditions.

This system is under development, so it can be assumed that this type of power transmission without a conductor will still be developed and, possibly, will be introduced into the modern transport industry.

State-of-the-art power transmission developments

In modern realities, wireless electricity is once again becoming an important direction in the study and design of devices. There are the most promising ways to develop wireless power transmission, which include:

1. The use of electricity in mountainous areas, in cases where it is not possible to lay carrier cables to the consumer. Despite the study of the issue of electricity, there are places on earth where there is no electricity, and the people living there cannot enjoy such a blessing of civilization. Of course, autonomous power sources are often used there, such as solar panels or generators, but this resource is limited and cannot fully meet the needs;
2. Some manufacturers of modern household appliances are already introducing devices for transmitting energy without wires into their products. For example, a special unit is offered on the market, which is connected to the mains supply and, by converting direct current into microwave waves, transmits them to surrounding devices. The only condition for using this device is that household appliances have a receiving device that converts these waves into direct current. There are televisions on the market that are completely powered by wireless energy received from the transmitter;
3. For military purposes, in most cases in the defense sector, there are developments of communication devices and other auxiliary devices.

A big breakthrough in this field of technology occurred in 2014, when a group of scientists developed a device for generating and receiving energy over a distance without wires, using a lens system placed between the transmitting and receiving coils. Previously, it was believed that the transmission of current without a conductor is possible at a distance not exceeding the size of the devices, so a huge structure was required to transport electricity over a long distance. But modern designers have changed the principle of operation of this device and created a transmitter that directs not microwave waves, but magnetic fields with low frequencies. In this case, electrons do not lose power and are transmitted over a distance in a concentrated beam, moreover, energy consumption is possible not only by connecting to the receiving part, but also simply by being in the area of ​​the fields.

1. Charging mobile devices without connecting to a cable;
2. The implementation of power for unmanned aerial vehicles is a direction that will be in great demand in both the civil and military industries, since such devices have recently become often used for various purposes.

The very procedure for transmitting data over a distance without the use of wires some time ago was considered a breakthrough in the research of physics and energy, now it no longer surprises anyone and has become accessible to any person. Thanks to the modern development of technologies and developments, the transportation of electricity by this method is becoming a reality and may well be implemented.

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For many years, scientists have been struggling with the issue of minimizing electrical costs. There are different ways and proposals, but the most famous theory is the wireless transmission of electricity. We propose to consider how it is carried out, who is its inventor and why it has not yet been brought to life.

Theory

Wireless electricity is literally the transmission of electrical energy without wires. People often compare the wireless transmission of electrical energy to the transmission of information such as radios, cell phones, or Wi-Fi Internet access. The main difference is that radio or microwave transmission is a technology aimed at restoring and transporting exactly information, and not the energy that was originally spent on transmission.

Wireless electricity is a relatively new area of ​​technology, but one that is growing rapidly. Methods are now being developed to efficiently and safely transfer energy over a distance without interruption.

How does wireless electricity work

The main work is based precisely on magnetism and electromagnetism, as is the case with radio broadcasting. Wireless charging, also known as inductive charging, is based on a few simple principles of operation, in particular, the technology requires two coils. A transmitter and receiver that together generate an alternating, non-constant current magnetic field. In turn, this field causes a voltage in the receiver coil; this can be used to power a mobile device or charge a battery.

If you direct an electric current through a wire, then a circular magnetic field is created around the cable. Despite the fact that the magnetic field affects both the loop and the coil, it manifests itself most strongly on the cable. When you take a second coil of wire that does not have an electric current passing through it, and place the coil in the magnetic field of the first coil, the electrical current from the first coil will be transmitted through the magnetic field and through the second coil, creating an inductive coupling.

Let's take an electric toothbrush as an example. In it, the charger is connected to an outlet that sends an electric current to a coiled wire inside the charger, which creates a magnetic field. There is a second coil inside the toothbrush, when the current starts to flow and, thanks to the formed magnetic field, the brush starts charging without it being directly connected to the 220 V power supply.

Story

Wireless power transmission as an alternative to the transmission and distribution of electric lines was first proposed and demonstrated by Nikola Tesla. In 1899, Tesla presented a wireless transmission to power a field of fluorescent lamps located twenty-five miles from a power source without the use of wires. But at the time, it was cheaper to wire 25 miles of copper wire rather than build the custom electrical generators that Tesla's experience requires. He was never granted a patent, and the invention remained in the bins of science.

While Tesla was the first person to demonstrate the practical possibilities of wireless communication back in 1899, today, there are very few devices on sale, these are wireless brushes, headphones, phone chargers and more.

Wireless technology

Wireless power transmission involves the transmission of electrical energy or power over a distance without wires. Thus, the core technology lies on the concepts of electricity, magnetism and electromagnetism.

Magnetism

It is a fundamental force of nature that causes certain types of material to attract or repel each other. Earth's poles are considered the only permanent magnets. The current flow in the loop generates magnetic fields that differ from oscillating magnetic fields in the speed and time required to generate alternating current (AC). The forces that appear in this case are shown in the diagram below.

This is how magnetism appears

Electromagnetism is the interdependence of alternating electric and magnetic fields.

Magnetic induction

If a conducting loop is connected to an AC power source, it will generate an oscillating magnetic field in and around the loop. If the second conducting loop is close enough, it will pick up some of this oscillating magnetic field, which in turn generates or induces an electric current in the second coil.

Video: how is the wireless transmission of electricity

Thus, there is an electrical transfer of power from one cycle or coil to another, which is known as magnetic induction. Examples of such a phenomenon are used in electrical transformers and generators. This concept is based on Faraday's laws of electromagnetic induction. There, he states that when there is a change in the magnetic flux connected to the coil, the EMF induced in the coil is equal to the product of the number of turns of the coil and the rate of change of the flux.

power clutch

This part is necessary when one device cannot transmit power to another device.

A magnetic link is generated when an object's magnetic field is capable of inducing an electrical current with other devices within its reach.

Two devices are said to be mutually inductively coupled or magnetically coupled when they are designed such that a change in current occurs when one wire induces a voltage at the ends of the other wire through electromagnetic induction. This is due to the mutual inductance

Technology

The principle of inductive coupling

The two devices, mutually inductively coupled or magnetically coupled, are designed such that the change in current when one wire induces a voltage at the ends of the other wire is produced by electromagnetic induction. This is due to mutual inductance.
Inductive coupling is preferred due to its ability to operate wirelessly as well as shock resistance.

Resonant inductive coupling is a combination of inductive coupling and resonance. Using the concept of resonance, you can make two objects work depending on each other's signals.

As you can see from the diagram above, resonance provides the inductance of the coil. The capacitor is connected in parallel to the winding. Energy will move back and forth between the magnetic field surrounding the coil and the electric field around the capacitor. Here, radiation losses will be minimal.

There is also the concept of wireless ionized communication.

It is also feasible, but here you need to make a little more effort. This technique already exists in nature, but there is hardly any reason to implement it, since it needs a high magnetic field, from 2.11 M/m. It was developed by the brilliant scientist Richard Volras, the developer of the vortex generator, which sends and transmits heat energy over great distances, in particular with the help of special collectors. The simplest example of such a connection is lightning.

Advantages and disadvantages

Of course, this invention has its advantages over wired methods, and disadvantages. We invite you to consider them.

The advantages include:

1. Complete absence of wires;
2. No power supplies needed;
3. The need for a battery is eliminated;
4. Energy is transferred more efficiently;
5. Significantly less maintenance required.

The disadvantages include the following:

• Distance is limited;
• magnetic fields are not so safe for humans;
• wireless transmission of electricity, using microwaves or other theories, is practically impossible at home and with your own hands;
• high installation cost.

Scientists have been studying the issue of transmitting electricity without wires for the third century. Recently, the issue has not lost its relevance, but, on the contrary, has taken a step forward, which is only pleasing. We decided to tell the readers of the site in detail how wireless transmission of electricity has developed over distances from the beginning to the present day, as well as what technologies are already being practiced.

History of development

The transmission of electricity over a distance without wires develops hand in hand with the progress in the field of radio transmission, because the principle of operation in these phenomena is in many respects similar, if not the same. Most of the inventions are based on the method of electromagnetic induction, as well as the electrostatic field.

In 1820 A.M. Ampère discovered the law of interaction of currents, which was that if two closely spaced conductors current flows in the same direction, then they are attracted to each other, and if they are in different directions, they repel each other.

M. Faraday in 1831 established in the process of conducting experiments that a variable (changing in magnitude and direction in time) magnetic field generated by the flow of electric current induces (induces) currents in nearby conductors. Those. transmission of electricity without wires. We discussed it in detail in an earlier article.

Well, J.K. Maxwell 33 years later, in 1864, translated Faraday's experimental data into a mathematical form, Maxwell's own equations are fundamental in electrodynamics. They describe how an electric current and an electromagnetic field are related.

The existence of electromagnetic waves was confirmed in 1888 by G. Hertz, in the course of his experiments with a spark transmitter with a chopper on a Ruhmkorff coil. In this way, EM waves were produced with frequencies up to half a gigahertz. It is worth noting that these waves could be received by several receivers, but they must be tuned to resonance with the transmitter. The range of the installation was in the region of 3 meters. When a spark appeared in the transmitter, the same spark appeared on the receivers. In fact, these are the first experiments in the transmission of electricity without wires.

Deep research was conducted by the famous scientist Nikola Tesla. In 1891 he studied alternating current of high voltage and frequency. As a result, the following conclusions were drawn:

For each specific purpose, you need to adjust the installation to the appropriate frequency and voltage. In this case, a high frequency is not a prerequisite. The best results were achieved at a frequency of 15-20 kHz and a transmitter voltage of 20 kV. To obtain a high frequency current and voltage, an oscillatory discharge of a capacitor was used. Thus, it is possible to transmit both electricity and produce light.

The scientist in his speeches and lectures demonstrated the glow of lamps (vacuum tubes) under the influence of a high-frequency electrostatic field. Actually, Tesla's main conclusions were that even in the case of using resonant systems, a lot of energy cannot be transmitted using an electromagnetic wave.

In parallel, a number of scientists were engaged in similar studies until 1897: Jagdish Bose in India, Alexander Popov in Russia and Guglielmo Marconi in Italy.

Each of them contributed to the development of wireless power transmission:

1. J. Bose in 1894, ignited gunpowder, transmitting electricity over a distance without wires. He did this at a demonstration in Calcutta.
2. A. Popov on April 25 (May 7), 1895, using Morse code, transmitted the first message. In Russia, this day, May 7, is still Radio Day.
3. In 1896, G. Marconi in the UK also transmitted a radio signal (Morse code) over a distance of 1.5 km, later 3 km on Salisbury Plain.

It is worth noting that Tesla's works, underestimated in their time and lost for centuries, surpassed the work of his contemporaries in terms of parameters and capabilities. At the same time, namely in 1896, his devices transmitted a signal over long distances (48 km), unfortunately this was a small amount of electricity.

And by 1899, Tesla comes to the conclusion:

The inconsistency of the method of induction seems to be enormous in comparison with the method of excitation of the charge of the earth and air.

These conclusions will lead to other research, in 1900 he managed to power a lamp from a coil in the field, and in 1903 the Wondercliff tower on Long Island was launched. It consisted of a transformer with a grounded secondary, and on top of it stood a copper spherical dome. With its help, it turned out to light 200 50-watt lamps. At the same time, the transmitter was located 40 km from it. Unfortunately, these studies were interrupted, funding was cut off, and free transmission of electricity without wires was not economically beneficial for businessmen. The tower was destroyed in 1917.

Nowadays

Wireless power transmission technologies have made great strides forward, mainly in the field of data transmission. So significant success has been achieved by radio communication, wireless technologies such as Bluetooth and Wi-fi. There were no special innovations, the frequencies, the methods of signal encryption were mainly changed, the signal representation switched from analog to digital form.

When it comes to the transmission of electricity without wires to power electrical equipment, it is worth mentioning that in 2007, researchers from the Massachusetts Institute transmitted energy over 2 meters and lit a 60-watt light bulb in this way. This technology is called WiTricity, it is based on the electromagnetic resonance of the receiver and transmitter. It is worth noting that the receiver receives about 40-45% of the electricity. A generalized diagram of a device for transmitting energy through a magnetic field is shown in the figure below:

The video shows an example of using this technology to charge an electric car. The bottom line is that a receiver is attached to the bottom of the electric car, and a transmitter is installed on the floor in a garage or other place.

You must position the car so that the receiver is above the transmitter. The device transmits a lot of electricity without wires - from 3.6 to 11 kW per hour.

In the future, the company is considering providing electricity with such technology and household appliances, as well as the entire apartment as a whole. In 2010, Haier introduced a wireless TV that receives power using a similar technology, as well as a video signal without wires. Similar developments are being carried out by other leading companies such as Intel and Sony.

In everyday life, wireless power transmission technologies are widespread, for example, for charging a smartphone. The principle is similar - there is a transmitter, there is a receiver, the efficiency is about 50%, i.e. to charge with a current of 1A, the transmitter will consume 2A. The transmitter is usually called the base in such kits, and the part that connects to the phone is called the receiver or antenna.

Another niche is the wireless transmission of electricity using microwaves or lasers. This provides a greater range than the parameters provided by magnetic induction. In the microwave method, a rectenna (a non-linear antenna for converting an electromagnetic wave into direct current) is installed on the receiving device, and the transmitter directs its radiation in this direction. In this version of the wireless transmission of electricity, there is no need for a direct line of sight of objects. The downside is that microwave radiation is unsafe for the environment.

In conclusion, I would like to note that wireless transmission of electricity is certainly convenient for use in everyday life, but it has its pros and cons. If we talk about using such technologies to charge gadgets, then the advantage is that you do not have to constantly insert and remove the plug from the connector of your smartphone, respectively, the connector will not fail. The downside is low efficiency, if energy losses are not significant for a smartphone (several watts), then for wireless charging of an electric car this is a very big problem. The main goal of development in this technology is to increase the efficiency of the installation, because against the background of the widespread race for energy saving, the use of technologies with low efficiency is very doubtful.

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Wireless transmission for delivering electricity has the ability to deliver major advances in industry and applications that depend on the physical contact of a connector. It, in turn, can be unreliable and lead to failure. The transmission of wireless electricity was first demonstrated by Nikola Tesla in the 1890s. However, it has only been in the last decade that technology has been used to the point where it offers real, tangible benefits for real-world applications. In particular, the development of a resonant wireless power system for the consumer electronics market has shown that inductive charging brings new levels of convenience to millions of everyday devices.

The power in question is widely known by many terms. Including inductive transmission, communication, resonant wireless network and the same voltage return. Each of these conditions essentially describes the same fundamental process. Wireless transmission of electricity or power from a power source to load voltage without connectors through an air gap. The basis is two coils - a transmitter and a receiver. The first is excited by an alternating current to generate a magnetic field, which in turn induces a voltage in the second.

How the system in question works

The basics of wireless power involve distributing power from a transmitter to a receiver through an oscillating magnetic field. To achieve this, the direct current supplied by the power supply is converted into high frequency alternating current. With specially designed electronics built into the transmitter. The alternating current activates a coil of copper wire in the dispenser, which generates a magnetic field. When the second (receiving) winding is placed in close proximity. The magnetic field can induce an alternating current in the receiving coil. The electronics in the first device then converts the AC back to DC, which becomes the power input.

Scheme of wireless power transmission

The "mains" voltage is converted into an AC signal, which is then sent to the transmitter coil via an electronic circuit. Flowing through the winding of the distributor, induces a magnetic field. It, in turn, can spread to the receiver coil, which is in relative proximity. The magnetic field then generates a current flowing through the winding of the receiving device. The process by which energy is distributed between the transmitting and receiving coils is also referred to as magnetic or resonant coupling. And it is achieved with the help of both windings operating at the same frequency. The current flowing in the receiver coil is converted to DC by the receiver circuitry. It can then be used to power the device.

What does resonance mean

The distance over which energy (or power) can be transmitted increases if the transmitter and receiver coils resonate at the same frequency. Just like a tuning fork oscillates at a certain height and can reach its maximum amplitude. It refers to the frequency at which an object naturally vibrates.

Benefits of Wireless Transmission

What are the benefits? Pros:

• reduces the costs associated with maintaining direct connectors (for example, in a traditional industrial slip ring);
• greater convenience for charging conventional electronic devices;
• secure transmission to applications that must remain hermetically sealed;
• electronics can be completely hidden, which reduces the risk of corrosion due to elements such as oxygen and water;
• reliable and consistent power supply to rotating, highly mobile industrial equipment;
• provides reliable power transmission to critical systems in wet, dirty and moving environments.

Regardless of the application, eliminating the physical connection provides a number of advantages over traditional cable power connectors.

The efficiency of the considered energy transfer

The overall efficiency of a wireless power system is the single most important factor in determining its performance. System efficiency measures the amount of power transferred between the power source (i.e. wall outlet) and the receiving device. This, in turn, determines aspects such as charging speed and propagation range.

Wireless communication systems vary in their level of efficiency based on factors such as coil configuration and design, transmission distance. A less efficient device will generate more emissions and result in less power passing through the receiving device. Typically, wireless power transmission technologies for devices such as smartphones can reach 70% performance.

How efficiency is measured

In the sense, as the amount of power (in percent) that is transmitted from the power source to the receiving device. That is, wireless power transmission for a smartphone with an efficiency of 80% means that 20% of the input power is lost between the wall outlet and the battery for the gadget being charged. The formula for measuring work efficiency is: performance = direct current outgoing divided by incoming, the result obtained multiplied by 100%.

Wireless methods of power transmission

Power can be distributed through the network under consideration in almost all non-metallic materials, including, but not limited to. These are solids such as wood, plastic, textiles, glass and bricks, as well as gases and liquids. When a metallic or electrically conductive material (i.e. placed in close proximity to an electromagnetic field) the object absorbs power from it and heats up as a result. This in turn affects the efficiency of the system. This is how induction cooking works, for example inefficient power transfer from the hob creates heat for cooking.

To create a wireless power transmission system, it is necessary to return to the origins of the topic under consideration. And, more precisely, to the successful scientist and inventor Nikola Tesla, who created and patented a generator that can take power without various materialistic conductors. So, to implement a wireless system, it is necessary to assemble all the important elements and parts, as a result, a small device will be implemented. This is a device that creates a high-voltage electric field in the air around it. At the same time, there is a small input power, it provides wireless transmission of energy at a distance.

One of the most important ways to transfer energy is inductive coupling. It is mainly used for near field. It is characterized by the fact that when current passes through one wire, a voltage is induced at the ends of another. Power transfer is done by reciprocity between the two materials. A common example is a transformer. Microwave energy transfer, as an idea, was developed by William Brown. The whole concept involves converting AC power to RF power and transmitting it in space and re-to AC power at the receiver. In this system, the voltage is generated using microwave energy sources. such as klystron. And this power is transmitted through the waveguide, which protects from the reflected power. As well as a tuner that matches the impedance of the microwave source with other elements. The receiving section consists of an antenna. It accepts microwave power and an impedance matching circuit and a filter. This receiving antenna, together with the rectifying device, may be a dipole. Corresponds to the output signal with a similar sound alert of the rectifier unit. The receiver block also consists of a similar section consisting of diodes which are used to convert the signal into a DC alert. This transmission system uses frequencies in the range of 2 GHz to 6 GHz.

Wireless transmission of electricity with the help of which the generator realized using similar magnetic oscillations. The bottom line is that this device worked thanks to three transistors.

The use of a laser beam to transmit power in the form of light energy, which is converted to electrical energy at the receiving end. The material itself is directly powered using sources such as the Sun or any electricity generator. And, accordingly, implements a focused light of high intensity. The size and shape of the beam are determined by the set of optics. And this transmitted laser light is received by photovoltaic cells, which convert it into electrical signals. It usually uses fiber optic cables for transmission. As with the basic solar power system, the receiver used in laser-based propagation is an array of photovoltaic cells or a solar panel. They, in turn, can convert the incoherent into electricity.

Essential features of the device

The power of the Tesla coil lies in a process called electromagnetic induction. That is, the changing field creates potential. It makes current flow. When electricity flows through a coil of wire, it generates a magnetic field that fills the area around the coil in a certain way. Unlike some other high voltage experiments, the Tesla coil has withstood many tests and trials. The process was quite laborious and lengthy, but the result was successful, and therefore successfully patented by the scientist. You can create such a coil in the presence of certain components. The following materials are required for implementation:

1. length 30 cm PVC (the more the better);
2. copper enameled wire (secondary wire);
3. birch board for the base;
4. 2222A transistor;
5. connection (primary) wire;
6. resistor 22 kΩ;
7. switches and connecting wires;
8. 9 volt battery.

Tesla Device Implementation Stages

First you need to place a small slot in the top of the pipe to wrap one end of the wire around. Wind the coil slowly and carefully, being careful not to overlap the wires or create gaps. This step is the most difficult and tedious part, but the time spent will give a very high quality and good coil. Every 20 or so turns, rings of masking tape are placed around the winding. They act as a barrier. In case the coil starts to unravel. When finished, wrap a tight tape around the top and bottom of the winding and spray it with 2 or 3 coats of enamel.

Then you need to connect the primary and secondary battery to the battery. After - turn on the transistor and resistor. The smaller winding is the primary and the longer winding is the secondary. You can optionally install an aluminum sphere on top of the pipe. Also, connect the open end of the secondary to the added one, which will act as an antenna. You need to create everything with great care not to touch the secondary device when you turn on the power.

There is a risk of fire if sold by yourself. You need to flip the switch, install an incandescent lamp next to the wireless power transmission device and enjoy the light show.

Wireless transmission via solar power system

Traditional wired power distribution configurations typically require wires between distributed devices and consumer units. This creates a lot of restrictions as the cost of system cabling costs. Losses incurred in transmission. As well as waste in distribution. Transmission line resistance alone leads to a loss of about 20-30% of the generated energy.

One of the most modern wireless power transmission systems is based on the transmission of solar energy using a microwave oven or a laser beam. The satellite is placed in geostationary orbit and consists of photovoltaic cells. They convert sunlight into electrical current, which is used to power a microwave generator. And, accordingly, realizes the power of microwaves. This voltage is transmitted using radio communication and received at the base station. It is a combination of antenna and rectifier. And it is converted back into electricity. Requires AC or DC power. The satellite can transmit up to 10 MW of RF power.

If we talk about a DC distribution system, then even this is impossible. Since it requires a connector between the power supply and the device. There is such a picture: the system is completely devoid of wires, where you can get AC power in homes without any additional devices. Where it is possible to charge your mobile phone without having to physically connect to the socket. Of course, such a system is possible. And a lot of modern researchers are trying to create something modernized, while studying the role of developing new methods of wireless transmission of electricity at a distance. Although, from the point of view of the economic component, it will not be entirely beneficial for states if such devices are introduced everywhere and replace standard electricity with natural electricity.

Origins and examples of wireless systems

This concept is not really new. This whole idea was developed by Nicholas Tesla in 1893. When he developed a system of illuminating vacuum tubes using wireless transmission techniques. It is impossible to imagine that the world exists without various sources of charging, which are expressed in material form. To make it possible for mobile phones, home robots, MP3 players, computers, laptops and other transportable gadgets to be charged on their own, without any additional connections, freeing users from constant wires. Some of these devices may not even require a large number of elements. The history of wireless power transmission is quite rich, and, mainly, thanks to the developments of Tesla, Volta, and others. But, today it remains only data in physical science.

The basic principle is to convert AC power to DC voltage using rectifiers and filters. And then - in the return to the original value at high frequency using inverters. This low voltage, highly oscillating AC power is then passed from the primary transformer to the secondary. Converted to DC voltage using a rectifier, filter and regulator. The AC signal becomes direct due to the sound of the current. As well as using the bridge rectifier section. The received DC signal is passed through a feedback winding which acts as an oscillator circuit. At the same time, it forces the transistor to conduct it into the primary converter in the direction from left to right. When current passes through the feedback winding, the corresponding current flows to the primary of the transformer in the direction from right to left.

This is how ultrasonic energy transfer works. The signal is generated through the sensor for both half cycles of the AC alert. The sound frequency depends on the quantitative indicators of the vibrations of the generator circuits. This AC signal appears on the secondary winding of the transformer. And when it is connected to the transducer of another object, the AC voltage is 25 kHz. A reading appears through it in a step-down transformer.

This AC voltage is equalized by a bridge rectifier. And then filtered and regulated to get a 5V output to drive the LED. The 12V output voltage from the capacitor is used to power the DC fan motor to run it. So, from the point of view of physics, the transmission of electricity is a fairly developed area. However, as practice shows, wireless systems are not fully developed and improved.

In 1968, the American space research specialist Peter E. Glaser proposed placing large solar panels in geostationary orbit, and transmitting the energy they generate (5-10 GW level) to the Earth's surface with a well-focused beam of microwave radiation , then convert it into energy of direct or alternating current of technical frequency and distribute it to consumers.

Such a scheme made it possible to use the intense flux of solar radiation that exists in the geostationary orbit (~ 1.4 kW/sq.m.) and to transfer the received 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 plane of the ecliptic with an angle of 23.5 degrees, a satellite located in a geostationary orbit is illuminated by a flux of solar radiation almost continuously, except for 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 heavy precipitation, have little effect on the efficiency of power transmission. The 5.8 GHz band is tempting because it allows you to reduce the size of the transmitting and receiving antennas. However, the influence of meteorological conditions here already requires further study.

The current level of development of microwave electronics allows us to speak of a rather high efficiency of energy transfer by a microwave beam from a 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-based rectenna has dimensions of 10 km x 13 km for a latitude of 35 degrees. SCES with an output power level of 5 GW has a radiated power density in the center of the transmitting antenna of 23 kW/sq.m., in the center of the receiving antenna - 230 W/sq.m.

Various types of solid-state and vacuum microwave generators for the SCES transmitting antenna were investigated. William Brown showed, in particular, that magnetrons, which are well mastered by the industry, designed for microwave ovens, can also be used in transmitting antenna arrays of SCES, if each of them is provided with its own negative feedback circuit in phase with respect to an external synchronizing signal (so called, Magnetron Directional Amplifier - MDA).

The most active and systematic research in the field of SCES was conducted by Japan. In 1981, under the guidance of professors M. Nagatomo (Makoto Nagatomo) and S. Sasaki (Susumu Sasaki), research was started at the Space Research Institute of Japan to develop 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 of 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 a mobile phone. “The phone would not stop, demanding that I put it on charge,” says Soljacic. Tired and not going to get up, he began to dream that the phone, once at home, would start charging by itself..

In 2012-2015 University of Washington engineers 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 itself has made a real revolution. And now it's the turn of wireless power transmission over the air, which the developers from the University of Washington called PoWiFi (from Power Over WiFi).

During the testing phase, the researchers were able to successfully charge low-capacity lithium-ion and nickel-metal hydride batteries. Using the Asus RT-AC68U router and several sensors located at a distance of 8.5 meters from it. These sensors just convert the energy of an electromagnetic wave into a 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. It is enough just to reflash the router, and you can use it as usual, plus supply power to low-power devices. One demonstration successfully powered a small, low-resolution covert surveillance camera located more than 5 meters away from a router. Then the Jawbone Up24 fitness tracker was charged to 41%, it took 2.5 hours.

To tricky questions about why these processes do not negatively affect the quality of the network communication channel, the developers replied that this becomes possible due to the fact that a flashed router, during its operation, sends energy packets through unoccupied information transfer channels. They came to this decision when they discovered that during periods of silence, energy simply flows out of the system, and in fact it can be directed to power low-power devices.

During the study, the PoWiFi system was placed in six houses, and the residents were invited to use the Internet as usual. Load web pages, watch streaming video, and then tell them what's changed. As a result, it turned out that network performance did not change in any way. 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 may well serve to power sensors built into household appliances and military equipment in order to control them wirelessly and carry out remote charging / recharging.

Relevant is the transfer of energy for the UAV (most likely already using PoWiMax technology or from the radar of the carrier aircraft):

For UAVs, the negative from the inverse square law (isotropically emitting antenna) partially “compensates” for the antenna beamwidth and radiation pattern:

After all, the LA radar in an impulse can produce EMP energy under 17 kW.

This is not a cellular connection - where the cell must provide a 360 degree connection to the end elements.
Let's have this variation:
The aircraft carrier (for Perdix) is the 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 an impulse should give out under 15 kW of EMP energy

This is enough to extend the active life of Perdix Micro-Drones from the current 20 minutes to an hour or 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 for the younger brothers Perdix Micro-Drones via PoWiFi / PoWiMax, simultaneously exchanging information with them (flight-aerobatic, target tasks, swarm coordination).

Perhaps soon it will come to charging cell phones and other mobile devices that are in range of Wi-Fi, Wi-Max or 5G?

Afterword: 10-20 years, after the widespread introduction of numerous electromagnetic microwave emitters into everyday life (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 the zoo. They suddenly disappeared from the homes they used to love so much.

COCKROACHES CARL!
These monsters, the leaders of the list of "radioresistant organisms" shamelessly capitulated!
Reference
LD 50 - 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 levels of radiation from mobile base stations (900 and 1800 MHz, the total level from all sources) in the sanitary-residential zone in some countries differ markedly:
Ukraine: 2.5 µW/cm². (the most stringent 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.
The temporary allowable level (TDL) from mobile radiotelephones (MRT) for users of radiotelephones in the Russian Federation is defined as 10 μW / cm² (Section IV - Hygienic requirements for mobile land radio stations SanPiN 2.1.8 / 2.2.4.1190-03 "Hygienic requirements for placement and operation means of land mobile radio communications).
In the USA, the Certificate is issued by the Federal Communications Commission (FCC) for cellular devices whose maximum SAR level does not exceed 1.6 W/kg (moreover, the absorbed radiation power is reduced to 1 gram of human 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 (with the absorbed radiation power given to 10 grams of human tissue).
More recently, in the UK, a level of 10 W/kg was considered a safe SAR level. A similar pattern was observed in other countries as well.
The maximum SAR value accepted in the standard (1.6 W/kg) cannot even be safely attributed to “hard” or “soft” standards.
Standards for determining the SAR value adopted both in the USA and in Europe (all the regulation of microwave radiation from cell phones, which we are talking about, 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 how much?
And what about the wireless transmission of electricity by microwave technology?
Here the power is not watts and miles of watts, but already kW ...

Note: A typical WiMAX base station radiates at approximately +43 dBm (20 W), while a mobile station typically transmits at +23 dBm (200 mW).

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• Electricity
• microwave
• WiFi
• drones
• UAV

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