adminWIRELESS POWER TRANSMISION (WPT)
Wireless power transfer is a technology that enables electricity to be transmitted from a power source to an electrical device without the need for physical connectors or wires. In a wireless power transmission system an electrically powered transmission device generates a time varying electromagnetic field that transmits power across space to a receiver device and ultimately to an electrical load.
There are several types of wireless power transmission techniques and they are; inductive coupling, resonant coupling, capacitive coupling, microwave power transmission and laser power transmission.
Inductive coupling wireless power transmission uses electromagnetic fields to transfer power between two coils, a transmitter coil in the charging pad for a wireless charger or a base station and a receiver coil in the device being charged. When the coils are closely aligned, electrical current flows from the power source to the receiver coil which can be used, to charge a battery or power the device.
Resonant coupling is an extension of inductive charging that uses resonance to improve power transfer efficiency. It involves tuning the transmitter and the receiver coils to the same resonant frequency, thereby allowing for more efficient power transfer over a greater distance.
Capacitive coupling uses electric fields to transfer energy between two electrodes. In this technique, an alternating voltage generated by the transmitter is applied to the transmitting plate and the oscillating electric field induces an alternating potential on the receiver plate by electrostatic induction, which causes an alternating current to flow in the load circuit.
Microwave power transmission uses microwaves to transfer energy over long distances.in this technique, the electrical energy is converted to microwave energy. To do this, alternating current is converted to direct current and direct current is subsequently converted to microwave energy or current using the magnetron. The microwaves are then transmitted from a base station to the receiver or mobile device. After the transmission, an antenna receives the microwave energy that is consequently converted back to electrical energy at the output.
Laser power transmission uses lasers to transfer or transmit energy over long distances. In this technique, electrical energy is transformed into a laser beam that can be channeled to a given receiver, which later converts the laser beam back to electrical energy. The transmitted laser is received by photo-voltaic cells which converts it to electrical signals.
The advantages of wireless transfer transmission are as follows; wireless power transmission eliminates the need for cables and contactors making it easier to charge and transmit power to devices. Wireless power transmission reduces the risk of electrocution and the need of maintenance of the mechanical contactor and equipment. Wireless power transmission reduces wear and tear on equipment and devices thereby increasing their service life.
The disadvantages of wireless power transmission are; wireless power transmissions are less efficient than the conventional wired power transmission. Wireless power transmissions are prone to interference from other devices and have a limited transmission range. Wireless power transmission equipment and devices are very expensive, complex to maintain and deploy.
Wireless power transmission find application in a variety of industries such as consumer electronics, electricity generation and transmission, electric vehicles, space vehicles, medical implants, industrial automation and space based solar power transmission to earth or remote station systems.
The future of wireless power transmission is based on the developments aimed at improving efficiency, increasing the power transfer over long distances and reducing costs.
SOURCES:
- Wireless power transfer: Principles and practice by Zhen Zhang and Wenxing Zhong.
- Inductive power transfer: Fundamentals and applications by Mariam K. Kazimierczuk and Dariusz Czarkowski.
- Wireless power transfer via strongly coupled magnetic resonances by Andre Kurs,Aristeidis Karalis, Robert Moffatt, J.D Joannopoulos, Peter Fisher and Marin Soljacic.
- Wireless power transfer: Theory, technology and applications by Naoki Shinohara.
- Inductive and capacitive wireless power transfer by NIcolae Marius Bica and Adrian Ioan Lita.
