Wireless mobile charging by Inductive Coupling.

Wireless Charging Circuit Using Inductive Coupling

BY:-Siddhant Singh

Overview

What is wireless power transmission(WPT)?

Why is WPT?

History of WPT

Types of WPT◦ Techniques to transfer energy wirelessly

Advantages and disadvantages

Applications

Conclusion

References 11/2/14 Wireless Power

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What is WPT?

The transmission of energy from one place to another without using wires

Conventional energy transfer is using wires

But, the wireless transmission is made possible by using various technologies

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Why WPT?

ReliableEfficientFastLow maintenance costCan be used for short-range

or long-range.11/2/14 Wireless Power

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History

Nikola Tesla in late 1890s

Pioneer of induction techniques

His vision for “World Wireless System”

The 187 feet tall tower to broadcast energy

He managed to light 200 lamps from a distance of 40km

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Energy Coupling

The transfer of energy◦ Magnetic coupling

◦ Inductive coupling

Simplest Wireless Energy coupling is a transformer

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Inductive coupling

Primary and secondary coils are not connected with wires.

Energy transfer is due to Mutual Induction

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An example

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Block Diagram of circuit

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Description of diagram

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Works on the principle of inductive coupling

Contains two sections-The Transmitter section and the Receiver section

Transmitter coil converts the DC power to high frequency AC signal

Receiver coil receives the power and convert it into AC signal

Transmitter Section

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Transmitter Section Description DC power Source: It consists of a step

down transformer that step downs the supply voltage to a desired level, and a rectifer circuit convert that AC voltage to DC signal

Oscillator Circuit: A modified Royer Oscillator circuit is used in our project. With this circuit we can easily achieve a high oscillating current for the transmitter coil.

Two N channel enhancement power MOSFET are used

Two chokes (L1 & L2) are used

capacitor C (works as a resonating capacitors)

diode D1 & D2( provide cross coupled feedback)

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Transmitter Section (cont…)

the transmitter coil L(inductor)

resistors R1,R2,R3 and R4 (works as a biasing network for Q1&Q2)

The operating frequency of the oscillator is determined by the resonance formula given below

F = ½ × π × √ (LC)

The equation for finding the inductance of a single layer air core coil is given below.

L = 0.001 N2 (a/2)2 / (114a + 254l) H

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Recevier Section

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Reciver Section Description

consists of receiver coil

rectifier circuit and a voltage regulator IC.

The rectifier circuit in the receiver section converts this AC voltage in to DC

Voltage control IC helps to provide a constant limited regulated output voltage to the load for charging

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Recevier section (cont….)

LM 7805 voltage regulator IC is used

The IC gives a regulated 5V as its output

It don’t allow more than 5V to the output.

Copper wire having diameter of 8cm is used.

equation for finding the inductance of a single layer air core coil is given below

L = 0.001 N2 (a/2)2 / (114a + 254l) H

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Advantages of near-field techniquesNo wires

No e-waste

Need for battery is eliminated

Efficient energy transfer using RIC

Harmless, if field strengths under safety levels

Maintenance cost is less

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Disadvantages

Distance constraint

Field strengths have to be under safety levels

Initial cost is high

In RIC, tuning is difficult

High frequency signals must be the supply

Air ionization technique is not feasible11/2/14 Wireless Power

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Applications

Near-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)11/2/14 Wireless Power Transmission

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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

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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

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THANK YOU!

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