Non-radiant Technique for Transfer of Wireless Power

The two primary subcategories of wireless power technologies are near field and far field. By using magnetic fields and inductive coupling between wire coils or electric fields and capacitive coupling between metal electrodes, near-field or non-radiative techniques transfer power across small distances. The most common wireless technology is inductive coupling, which has numerous uses, including wireless charging or continuous wireless power transfer in implantable medical devices like artificial cardiac pacemakers or electric vehicles as well as handheld devices like phones and electric toothbrushes, RFID tags, and induction cooking. A wireless power system typically consists of a “transmitter” device that is connected to a power source, such as a mains power line, and transforms the power into a time-varying electromagnetic field, and one or more “receivers” that take in the power and transform it back into DC or AC electric current used by an electrical load.
The oldest and most frequently utilized wireless power method to date, inductive coupling is essentially the only one employed in consumer goods today. Electric shock risk is decreased by using it in inductive charging stands for cordless devices used in moist settings, such as electric toothbrushes and shavers. In order to avoid having cables pass through the skin, “transcutaneous” charging of biomedical prosthetic devices implanted in human bodies, such as insulin pumps and cardiac pacemakers, is another application field. Additionally, it is utilized to either power or charge electric vehicles like automobiles and buses as well as transit vehicles like trains and buses. Modern inductive wireless power systems are now widely incorporating resonance technology. Area wireless power coverage is one of the potential uses for this technology. A coil installed in a room’s wall or ceiling may be able to wirelessly power lights and portable electronics everywhere in the space with a respectable level of efficiency. A significant reduction in the 6 billion batteries disposed of annually, a significant source of toxic waste and groundwater contamination, would be achieved by wirelessly charging tiny gadgets like clocks, radios, music players, and remote controls.
Using an anode and a cathode to create a capacitance, capacitive coupling, also known as electric coupling, uses electric fields to transmit power between the two electrodes. Energy is transferred between electrodes, such as metal plates, through capacitive coupling, also known as electrostatic induction, which is the conjugate of inductive coupling. The gap between the transmitter and receiver electrodes serves as the dielectric in a capacitor. The oscillating electric field induces an alternating potential on the receiver plate through electrostatic induction, which results in an alternating current flowing in the load circuit. The oscillating electric field applies an alternating voltage produced by the transmitter to the transmitting plate.
The receiver of an electro-dynamic wireless power transmission system has a permanent magnet that rotates or resonates mechanically. One or more electromechanical transduction techniques (such as electromagnetic/induction, piezoelectric, or capacitive) transform the mechanical motion of the resonating magnet into electricity when it is exposed to a time-varying magnetic field.
In magneto-dynamic coupling, power is transferred between two synchronously rotating armatures one in the transmitter and one in the receiver using a magnetic field produced by permanent magnets on the armatures. The magnetic field of the transmitter armature causes it to rotate, either as the rotor of an electric motor or independently. The magnetic field functions between the armatures like a mechanical coupling. Either by rotating a separate electric generator or by acting as the generator’s rotor itself, the receiver armature generates power to move the load.