WIRELESS POWER TRANSMISSION Presented by RADHIKA K ROLL NO:-14C91D4312 BRANCH:-ELECTRONICS & ELECTRICAL ENGINEERING.

OVERVIEW INTRODUCTION DEFINITION HISTORY TYPES OF WPT Atmospheric conduction method Electrodynamic induction method Advantages and disadvantage Applications Conclusion References

INTRODUCTION One of the major issues in power system is the losses occurring during the transmission and distribution of electrical power. The percentage of loss of power during transmission and distribution is approximated as 26%. The main reason for power loss during transmission and distribution is the resistance of wires used in grid. According to the World Resources Institute (WRI), India’s electricity grid has the highest transmission and distribution losses in the world – a whopping 27-40%. Tesla has proposed methods of transmission of electricity using electromagnetic induction.

DEFINITION As the word wireless means “without wire”. Wireless energy transfer or wireless power is the transmission of electrical energy from a power source to an electric load without interconnecting man made conductors. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous or impossible.

HISTORY Sir NICOLAI TESLA was the first one to propose and research the idea of wireless transmission in 1899, since than many scholars and scientists have been working to make his dream a reality. 1899: Tesla continues wireless power transmission research in Colorado Springs and writes, "the inferiority of the induction method would appear immense as compared with the disturbed charge of ground and air method 1961: William C. Brown publishes an article exploring possibilities of microwave power transmission 2009: Sony shows a wireless electrodynamics-induction powered TV set, 60 W over 50 cm

METHODS Different methods of transmission proposed by different scientist and scholars are: Atmospheric conduction method of Tesla 2. Electrodynamic induction method: Microwave method Laser method

Atmospheric conduction method In 1899 Sir NICOLAI TESLA and HEINRICH HERTZ powered a fluorescent lamp keeping it 25 miles away from source without using wire. Wireless power transmission experiments at WARDEN CLYFFE High frequency current, of a Tesla coil, could light lamps filled with gas (like neon). In this method a closed circuit is made using transmitter, ionized path between upper atmosphere and transmitter, second ionized path connecting receiver. The circuit back to the transmitter is completed through the earth .

Atmospheric conduction method High potential is maintained at transmitter and receiver end as well. A high potential transmitter transmits an “electromotive impulse” through the ionized path to the upper atmosphere where it ionizes the air, and this air between the transmitter and receiver would conduct like a neon tube .

LIMITATIONS OF ATMOSPHERIC CONDUCTION METHOD Economically challenging. Periodic changes in atmospheric condition. Maintaining high tower potential every time.

ELECTRODYNAMIC INDUCTION METHOD We bring electromagnetic radiation into practice, which uses far field technique in order to achieve range into kilos, which includes two techniques: LASERS MICROWAVE

LASER transmission LASER is highly directional, coherent Not dispersed for very long But, gets attenuated when it propagates through atmosphere Simple receiver Photovoltaic cell Cost-efficient

LASER METHOD In the case of electromagnetic radiation closer to visible region of spectrum (10s of microns (um) to 10s of nm), power can be transmitted by converting electricity into a laser beam that is then pointed at a solar cell receiver.  This mechanism is generally known as "power beaming" because the power is beamed at a receiver that can convert it to usable electrical energy. OPTICAL FIBRE TRANSFORMER LASER CURRENT CURRENT

MICROWAVE METHOD Power transmission via radio waves can be made more directional, allowing longer distance power beaming, with shorter wavelengths of electromagnetic radiation, typically in the microwave range. A rectenna may be used to convert the microwave energy back into electricity. Rectenna conversion efficiencies exceeding 95% have been realized. Power beaming using microwaves has been proposed for the transmission of energy from orbiting solar power satellites to Earth. The principle of Evanescent principle of Electromagnetic Wave Coupling extends the induction.

Applications Near-field energy transfer Far-field energy transfer Electric automobile charging Static and moving Consumer electronics Industrial purposes Harsh environment Far-field energy transfer Solar Power Satellites Energy to remote areas Can broadcast energy globally (in future)

ADVANTAGES Efficient Easy Need for grids, substations etc are eliminated Low maintenance cost More effective when the transmitting and receiving points are along a line-of-sight Can reach the places which are remote

DISADVANTAGES When microwaves are used, interference may arise When LASERS are used, conversion is inefficient due to absorption losses. It is radioactive in nature Distance constraint , initial cost is high. Field strength has to be under safety levels High frequency signals should be supplied for air ionization which is not feasible.

CONCLUSION Transmission without wires- a reality Efficient Low maintenance cost. But, high initial cost Better than conventional wired transfer Energy crisis can be decreased Low loss In near future, world will be completely wireless

References S. Sheik Mohammed, K. Ramasamy, T. Shanmuganantham,” Wireless power transmission – a next generation power transmission system”, International Journal of Computer Applications (0975 – 8887) (Volume 1 – No. 13) Peter Vaessen,” Wireless Power Transmission”, Leonardo Energy, September 2009 C.C. Leung, T.P. Chan, K.C. Lit, K.W. Tam and Lee Yi Chow, “Wireless Power Transmission and Charging Pad” David Schneider, “Electrons unplugged”, IEEE Spectrum, May 2010 Shahrzad Jalali Mazlouman, Alireza Mahanfar, Bozena Kaminska, “Mid-range Wireless Energy Transfer Using Inductive Resonance for Wireless Sensors” Chunbo Zhu, Kai Liu, Chunlai Yu, Rui Ma, Hexiao Cheng, “Simulation and Experimental Analysis on Wireless Energy Transfer Based on Magnetic Resonances”, IEEE Vehicle Power and Propulsion Conference (VPPC), September 3-5, 2008