This document discusses wireless power transmission through resonant inductive coupling. It explains that resonant inductive coupling transfers power between two resonant circuits, one in the transmitter and one in the receiver, that are tuned to the same resonant frequency. This can achieve high efficiency over ranges of 4 to 10 times the coil diameter. It then compares resonant inductive coupling to traditional inductive coupling, noting that resonant inductive coupling is more efficient and has a greater range. The document concludes by providing simulation results for the wireless power transfer system and calculating its efficiency.

1. Wireless Power Transmission

2. Inductive coupling
• Primary and secondary coils are not
connected with wires.
• Energy transfer is due to Mutual Induction
2

3. CIRCUIT SCHEMATICS

4. working

5. 5

6. Resonant inductive coupling
Resonant inductive coupling is a form of inductive coupling in
which power is transferred by magnetic field between
two resonant circuits , one in the transmitter and one in the
receiver .
The two are tuned to resonate at the same resonant frequency.

7. • In 2007 a team led by Marin Soljačić at MIT used two coupled tuned
circuits each made of a 25 cm self-resonant coil of wire at 10 MHz to
achieve the transmission of 60 W of power over a distance of 2 meters
(6.6 ft) (8 times the coil diameter) at around 40% efficiency.
• The two are tuned to resonate at the same resonant frequency.
• Resonant inductive coupling can achieve high efficiency at ranges of 4 to
10 times the coil diameter .
• An environmental and economic benefit of wirelessly powering small
devices such as clocks, radios, music players and remote controls is that it
could drastically reduce the 6 billion batteries disposed of each year, a
large source of toxic waste and groundwater contamination

8. RIC vs Inductive coupling
• RIC is highly efficient.
• RIC has much greater range than inductive
coupling.
• RIC is directional when compared to inductive
coupling.
• Devices using RIC technique are highly
portable.

9. Simulation of the RIC
clc
clear all
% input data for the wireless power transfer through concert.
v=input('input voltage in volts V=');
f=input(' frequency in HZ F =');
x1=input('reactance of pri.winding in ohms X1 =');
x2=input('reactance of sec.winding in ohms X2 =');
xL=input('reactance of magnatic circuit in ohms XL =');
xc1=input('capacitance reactance of pri.winding side in ohms
XC1=');
%xc2=input('capacitance reactance of sec.winding side in
ohms
XC2=');

10. r1=input('resistance of pri.winding in ohms r1 =');
r2=input('resistance of sec.winding in ohms r2 =');
rc=input('resistance of magnatic circuit in ohms rc =');
RL=input('load resistance of in ohms RL =');
xc2=(xL+x2);
w0=2*pi*f;
c2=(1/(w0*xc2));
c1=(1/(w0*xc1));
B=0;
if c1==B
z=((xL/(xL+x2))^2*RL)+j*((xL*x1+x1*x2+x2*xL)/(xL+x2));
fprintf('nthe value of z when C1=0 is
=%f%+fiohms',real(z),imag(z));

11. End
if c1~=B
z=(((xL/(xL+x2))^2*RL)^2)/((xL*x1+x1*x2+x2*xL)/(xL+x2))+((
xL*x1+x1*x2+x2*xL)/(xL+x2));
fprintf('n the value of z when C1~=0 is =%f%ohms',real(z));
end
turnsratio=1;
% to find effeiency of he system.
k=input('n Turns Ratio=');
if k==turnsratioalpha=(xL+x2)/xL;
IL=v/RL;
I1=alpha*IL;
I2=IL*(sqrt(1+(RL/xc2)^2));
I0=I1-I2;
pf=xc2/(RL^2+xc2^2);
%I0^2=IL^2*(alpha^2+(1+(RL/xc2)^2)-
2*alpha*sqrt(1+(RL/xc2)^2*pf);
eff=RL/((RL+r1*alpha^2+r2*(1+(RL/xc2)^2))+rc*(alpha^2+1+(R
L/xc2)^2-2*alpha*sqrt(1+(RL/xc2)^2*pf)));
eff1=eff*100;
fprintf('n the efficiency of the system =%f%',eff1);
end

12. 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