How does the wireless charger work?

Even if you organize your environment in the best possible way, there are probably still some dusty electrical wires around your house. You may even have had to unsightly route a particular cord to an outlet, hoping to find enough room to plug in chargers for various devices that happen to come with short cords. In general, although these tangled wires have made people's lives easier, they can literally create a mess. For this reason, various types of wireless chargers with interesting technologies have entered the market, to save you from all these messes. But have you ever thought about how wireless or wireless charger works?

The history of wireless electricity transmission (wireless charger)

h2>

It is interesting to know that although this idea may seem futuristic at first glance, it is not new at all! In the late 1800s and early 1900s, Nikola Tesla presented theories on wireless energy transmission to the public, one of his most spectacular demonstrations being remote electrification (artificial lightning capable of discharging electricity up to millions of volts) in his laboratory in Colorado Springs. . Although Tesla's work was impressive, it did not immediately lead to widespread and practical methods of transmitting electricity wirelessly. Since then, researchers have developed several different techniques to transmit electricity over long distances without the use of wires. Some remain only as theories or prototypes, but others are with you today, like the electric toothbrush you probably use every day.

Radio waves are energy, and people use them every day to send and receive messages. Receive mobile phone, TV, radio and Wi-Fi signals.

Today, wireless energy transfer has become a common topic in many parts of the world. Radio waves are energy and people use them every day to send and receive mobile phone, TV, radio and Wi-Fi signals. In general, radio waves have the ability to spread in all directions and be absorbed by antennas that are adjusted to the frequency corresponding to the waves.

1. Charging the device using the inductive coupling method

In order to understand the function of electricity transfer using the inductive coupling method, we proceed with the description of the electric toothbrush. In general, the base and handle of an electric toothbrush contain coils that allow the battery to be recharged. This is done through the inductive coupling process, which uses magnetic fields that are naturally produced by the movement of electric current inside the coil.

Whenever an electric current passes through the coil, the magnetic field A circular shape is created around the coil. In this regard, the increase of the curved wires around the coil core strengthens the magnetic field. So the more coils there are, the bigger the magnetic field! If the second coil (in the handle of the toothbrush) is placed in the magnetic field created by the first coil (in the base of the toothbrush or the charger), the first magnetic field can induce an electric current in the second coil, and thus the electric toothbrush is charged. /p>

Charging an electric toothbrush by induction coupling (wireless charger) )

In general, the same principle is used to recharge other devices and gadgets using A variety of wireless chargers are also used. Of course, there are other ways to transfer electricity over longer distances, which we will discuss in the next section.

2. Resonance and wireless Power charging devices

Household devices generate relatively small magnetic fields. For this reason, chargers that are placed at a great distance from the mother device cannot be charged by inductive method, because as you have seen, for charging by inductive coupling method, the coil of the charger and the mother device need to be close to each other. Of course, it may occur to you why larger and stronger fields are not used to induce current in devices that are far apart, to which the answer must be said, such a process is not efficient enough; In fact, since a magnetic field spreads out in all directions, making it bigger can waste a lot of energy and thus have little practical efficiency.

However, in November 2006, MIT researchers reported They gave who have designed an efficient way to transfer electric current between coils that are several meters apart. This team, led by Marin Soljacic, put forward the theory that by adding the resonance parameter to the current transfer equations, the distance between the coils can be increased and a resonant wireless charger can be created. But what exactly is resonance?

A good way to understand the phenomenon of resonance is to look at it from the perspective of sound. The physical structure of an object, for example the size and shape of the horn, can be a factor in determining the natural frequency of vibration of that device. This frequency of natural vibrations is called "resonant frequency" or resonant frequency of that device in technical language. In general, it is easy to vibrate or sound objects (such as a trumpet) at their resonant frequency, but making the object vibrate at other frequencies can be difficult. For this reason, playing the trumpet can cause other trumpets near you to vibrate, because all trumpets, due to their similar shape and structure, have the same resonant frequency.

Research at MIT shows that if the fields If the electromagnetic surrounding the coils are intensified with the same frequency, the electric current induction operation can be carried out optimally with a slight difference. In this theory, a curved winding is used as an inductor, then a plate capacitor capable of holding electrical charge is connected to both ends of the winding. As electricity passes through this coil, the inductor starts to vibrate (amplify). As it is known, the resonance frequency (vibration movements) of this system is the result of the induction of the coil and the plate capacitor.

Like an electric toothbrush, this approach relies on two independent coils. Electricity traveling along an electromagnetic wave can tunnel from one coil to another, until both reach the same resonant frequency. This is exactly the case where the resonant frequency of one trumpet can cause other trumpets to vibrate. As long as both coils are out of range of each other, nothing happens because the fields around the coils are not strong enough to affect each other much. Similarly, if the two coils vibrate at different resonant frequencies, nothing happens. But if two resonant coils with the same frequencies are placed within a few meters of each other, the energy flow will move from the transmitter coil to the receiver coil.

According to this approach, a coil can charge any device within its range, provided the coils have the same resonant frequency.

Interestingly, according to this approach, a single coil can even send electricity to multiple receiving devices, as long as they are all at the same resonant frequency. Researchers call this method "non-radiative energy transfer" because it involves fixed fields around the coils and does not deal with fields that spread in all directions.

3. Ideas for wireless charging at very long distances

Whether you consider an inductive wireless charger or a resonance method for charging your electrical appliances, generally these two methods are not suitable for very long distances; Because in some cases, it is necessary to transmit electricity over distances of miles or even over distances as large as Earth to space! take out the ground This means that this unmanned aircraft, which was called "Stationary High Altitude Relay Platform" (SHARP), acted as a communication relay (a type of fast electrical switch that opens and closes by directing another electrical circuit). Instead of flying point-to-point, Sharp's small plane was capable of flying in circles two kilometers in diameter and at an altitude of about 13 miles (21 kilometers). The most important part of this story was that this plane could continue flying like this for months!

The secret of Sharp's long flight time was the presence of a large microwave transmitter on Earth. The circular flight path of this plane kept it within the range of this transmitter. On the other hand, a large disc-shaped rectifier antenna was designed just behind the wings of the aircraft, which converted the microwave energy from the transmitter into direct current (DC). Due to this interaction of microwave waves with the rectifier antenna of the Sharp plane When in range of an active transmitter, it had access to a constant power supply. Rectifier antennas play an essential role in many methods of wireless power transmission. These antennas are usually made of arrays of dipole antennas that have positive and negative poles and are connected to semiconductor diodes. In general, the events that occur using these antennas are as follows:

Other ideas Longer range energy transmission also relies on these rectifier antennas. In the meantime, the use of microwaves to transmit electricity from solar power plants on the moon to the earth has also been suggested! In this way, tens of thousands of receivers on the ground absorb this energy and the rectifier antennas convert it into electricity.

Microwave waves can easily pass through the atmosphere and antennas can transmit microwave waves very efficiently. Convert to electricity. In addition, ground rectifier antennas can be built into a lattice framework that allows sun and rain to reach the ground and minimize environmental impact. Along with all the advantages that these ideas have, they also come with disadvantages, including the following:

• Solar power plants on the moon need monitoring and maintenance. In other words, the project requires permanently manned bases on the moon.
• Only a certain part of the Earth has a direct line of sight to the moon at any given time. So in order to ensure that the entire planet has a constant power supply, a network of satellites must channel the microwaves!
• Many people resist the idea of being constantly inundated with microwaves, even if the danger

Although scientists have built prototypes of wirelessly powered aircraft, larger-scale applications, such as power stations on the moon, are still theoretical. However, as the Earth's population continues to grow, the demand for electricity will skyrocket, so discussions of wireless electricity generation may soon become a necessity rather than a cool idea. wireless charger from SafirSoft

• How does the camera work?

Source: howstuffworks