As the name suggests that transfer of power from a source to the particular electrical system or electrical device placed in three dimensional space without the use of any electrical wire, is said as wireless power transfer (WPT) in 3D space.
Wireless power transfer - Basic introduction.
At first, as it comes in mind, either power transferring without conductor is possible? , a dream or a reality? Yes, it is possible and being done.
Basic Principle of Wireless power transfer.
Wireless power transfer in 3D space can be done based on the Faraday’s law of electromagnetic induction. This law is obvious and popular that, “Changing in magnetic field lines result in the production of alternating current”.
Mainly for this type of system, there is a need of designing of two sub-systems: receiver designing and transmitter designing. One coil of each sub-system is coupled inductively with the other coil of sub-system. For the sake of understanding, it is just like a transformer’s internal phenomenon without a core but air core in this case. In the near future, wireless power transfer will be rapidly growing and would be more common in industries as well.
Methods for the Wireless Power Transfer
There are multiple methods based on the physical phenomenon that can be used for the transfer of power wireless-ly. These include like laser, radio waves and micro waves, inductive coupling, piezoelectric principle and strong electromagnetic resonance.
Laser based wireless power transfer
As laser beam which is actually a coherent light beam that has ability for high energies to transfer them. This sends energy in a line of sight from one point to the next. For instance, in a year 2003, NASA (The National Aeronautics and Space Administration) launched an aircraft that was remote-controlled and could be wirelessley energized by suitable photo-voltaic cell acting as energy receiver by means of beam of laser in 3D. With the fact that due to the non-availability of other suitable mechanism for energy transferring, NASA had strongly purposed to power satellites with this method in a year 2003.
Inductive coupling based power transfer
One of the method through inductive coupling (a method in which there are two LC circuits that are configured in a way that due to the change in current in one coil induces a voltage in the other one, by means of electromagnetic induction) is also achievable.
Inductive coupling method has very low efficiency, it can only be achieved with higher efficiency if two sub-system (receiver and transmitter) are closely placed. As efficiency relates inversely to the separation of two coils, this method is as such of not greatly concerned. Using strong electromagnetic resonance phenomenon, wireless energy transfer is also attainable up to many centimeters in distance with good efficiency.
General Components for Wireless Power Transfer
General block diagram of WPT
General Working of Wireless Power Transfer
As said early, the complete procedure of power transfer via air/ wireless is all due to the two sub-system: Transmitter part and Receiver part.
On the transmitter side, there is AC input. This ac input is rectified to get its output version in DC with proper DC to AC inverter followed by HF Transformer. First of all, dc is changed into high frequency ac current by proper designing of circuitry needed on the transmitter side. This ac acts as a booster for cooper coil wire of transmitter that ultimately causes the production of magnetic field lines.
Then receiver coil is set closely to the transmitter’s coil and that produced magnetic field can make an AC (alternating current) in the receiving coil. Designed circuitry in receiver parts alters it into required DC for load as operating power.
Pros and Cons of Wireless Power Transfer
Advantages of WPT
WPT has so many robust merits that bring a good news in the world of innovations.
- With the technique of inductive coupling, within short distance it really provides safely and highly efficient power transferring.
- Magnetic resonance coupling method provides with better transmission over long distance.
- Electromagnetic radiations provide highly efficient power transfer over somehow large distance.
- Wireless power transfer provides durability in terms of non-reliability on the physical connection needed for power transfer without the effect of air gap and friction.
Disadvantages of WPT
- Inductive coupling has major drawback due to the short distance transmission which that needs to be properly aligned.
- Adjusting the resonant frequency in case of magnetic resonance is not a simple task, especially when you have to deal with multiple devices.
- In case of electromagnetic radiations, they can bring health related issues like leukemia, damage of retina in some cases.
- Complex circuitry and designing challenges.
Applications of Wireless Power
- It includes both direct wireless power and automatic wireless charging devices.
- Electric automobile charging
- Electronic portable devices like mobile phones, tablets and laptops are being charged wirelessly.
- For industrial purposes under the harsh environment.
- In far field energy transfer, it includes solar power satellites, energy transfer to remote areas.
WPT Technology Based Innovations
Wireless power transfer has brought out many devices in the field of technology and innovation. In the market, the new D-Link 5G NR gateway is considered as one of the best routers of Wi-Fi designed by Taiwanese company. With the capability of receiving signals wirelessly from any internet service provider, it has ability to link strong internet signals for all the connected devices of house. This will be available in market for the public after the mid of 2019. It is much faster than the current 5G Verizon network which has also very high speed of about 300 MB in one second (30 mbps).
Market Trends of WPT
In a year 2015, 1 billion dollar was market revenue. The potential world market revenue expectations for the wireless power transfer were about 8.5 billion dollars at the end of year 2018. It is being said, due to great response in a world market, it would bring out great revenue for the manufacturers of transmitter and receiver for wireless power transfer.