acknowledgement - Apeejay College of Engineering, Sohna
acknowledgement - Apeejay College of Engineering, Sohna acknowledgement - Apeejay College of Engineering, Sohna
Wireless Power Transfer using Small Loop Antennas 181 Wireless Power Transfer using Small Loop Antennas Karan Goel # , Parikshit Vasisht * # Department of Electronics and Communication Engineering, Apeejay College Of Engineering, Sohna * Department of Electronics and Communication Engineering, Apeejay College Of Engineering, Sohna # Email:karan.goel09@gmail.com # 9911163191 * Email:parikshitvasisht@yahoo.com * 9899315555 Abstract— We propose an effective design to transfer electricity up to a non-negligible distance without any connecting wires using small loop Antennas. For demonstration we have designed a theoretical model for a prototype to transmit electric power up to 100W wirelessly over mid-range distance (5m) and light a 60W bulb. We also give an overview of the techniques used to design the prototype and compare the simulation and the actual practical results of the electronics hardware used. Keywords— Witricity, wireless power transfer, Orcad Pspice analysis A. Motivation I. INTRODUCTION For the past decade or so there has been a tremendous growth of autonomous electronic devices (such as I-pods, mobile phones, laptops, PDA etc) which rely primarily on stored chemical energy for their power needs. If a technology can be developed to transmit power wirelessly, it will get rid of wire mesh and clutter and portable devices could get charged wirelessly. inductive coupling in which the coils need not be in resonance to exchange energy. C. Our Approach Vs Existing Approach Serious research has been going on for the past few years to develop efficient techniques for transferring power wirelessly, most notably by the team of Kralis of MIT and their company called Witricity (which is a portmanteau for wireless electricity)[1].However there are a few notable differences between our approach and the one used by the MIT team. We have designed the antenna as a single turn coil which reduces the complexity and cost of antennas. Also the whole prototype including the electronics cointaing the RF Amplifier has been built indigenously using locally available parts to ensure minimum costs. Our experimental setup can be represented by the following diagram. Wireless power transfer can also be used to power nanodevices like MEMS and bio-tech devices like pacemakers, which would prevent the repetitive surgeries a patient needs to undergo for charging his pacemaker. The project required an extensive practical and theoretical knowledge of both Engineering electromagnetic theory and analog electronics and thus provided us with a challenging opportunity to understand these core concepts of Electrical engineering at a much deeper level. B. Theory The fundamental physics behind wireless energy transfer is magnetic resonance. This resonance is similar to the mechanical resonance which can be easily observed in the shattering of glass experiment. When two coils are in magnetic resonance, they tend to exchange energy between themselves while interacting negligibly with Extraneous objects. Note that the technique is different from simple Fig. 1 The Prototype setup Tryst Technical Conference, IIT Delhi 13-14 March, 2010
Wireless Power Transfer using Small Loop Antennas 182 II. POWER SUPPLY DESIGN The Power Supply is used to generate a High Frequency sinusoidal current which generates a HF alternating magnetic field when connected to the resonant coil (Transmitter). The schematic Diagram below shows Oscillator and the Voltage Amplifier stage of the power supply Fig. 5 Actual Digital Oscilloscope Output Fig. 2 10MHz Colpitts Oscillator and Voltage Amplifier Schematic The general purpose amplifier transistor Q2N3904 is used for designing the Oscillator and High voltage transistor MPSA44 is used in the first stage of the transistor. The first stage of voltage amplifier is designed with an input impedance of 50Ω and a voltage gain of about 55dB. A. Oscillator Design We decided to use the Colpitts Oscillator to generate the 10 MHz sinusoidal wave due to its low part count and inherent simplicity and stability. The circuit has been designed using Cadence Orcad Package and simulated using Pspice. The Oscillator circuit is shown in figure 2. The simulated output of oscillator has a peak voltage of ≈ 500mV [figure 4]. Thus we have acceptable performance and acceptable match between theoretical and practical results for the oscillator. Note that the noise on the waveform presents no disadvantage as we simply want to create a high frequency alternating magnetic field to transfer power and are not doing a communication protocol. (E.g. Modulation). B. Voltage Amplifier Design The ac π-model was used to analyse and design the voltage amplifier [figure 6]. Fig. 6 Equivalent π-model of voltage Amplifier The MPSA44 High Voltage transistor is biased with a collector current of IC=100mA. The circuit schematic is shown in figure 2. The Output Power of the voltage amplifier is 1W which is given to a Class AB Push Pull Power Amplifier with a Power gain of about 100.This gives an output power of 100W which is connected to the resonant coils. Fig. 4 Simulated Oscillator output in Pspice The Actual Digital Oscilloscope output of the breadboard prototype is ≈328mV [figure 5]. Tryst Technical Conference, IIT Delhi 13-14 March, 2010
- Page 2 and 3: ACKNOWLEDGEMENT The Tryst 2010 Team
- Page 4 and 5: 13. Neural Networks And Fuzzy Logic
- Page 8: Wireless Power Transfer using Small
Wireless Power Transfer using Small Loop Antennas 181<br />
Wireless Power Transfer using Small Loop Antennas<br />
Karan Goel # , Parikshit Vasisht *<br />
# Department <strong>of</strong> Electronics and Communication <strong>Engineering</strong>, <strong>Apeejay</strong> <strong>College</strong> Of <strong>Engineering</strong>, <strong>Sohna</strong><br />
* Department <strong>of</strong> Electronics and Communication <strong>Engineering</strong>, <strong>Apeejay</strong> <strong>College</strong> Of <strong>Engineering</strong>, <strong>Sohna</strong><br />
#<br />
Email:karan.goel09@gmail.com<br />
# 9911163191<br />
*<br />
Email:parikshitvasisht@yahoo.com<br />
* 9899315555<br />
Abstract— We propose an effective design to transfer electricity<br />
up to a non-negligible distance without any connecting wires<br />
using small loop Antennas. For demonstration we have designed<br />
a theoretical model for a prototype to transmit electric power up<br />
to 100W wirelessly over mid-range distance (5m) and light a 60W<br />
bulb. We also give an overview <strong>of</strong> the techniques used to design<br />
the prototype and compare the simulation and the actual<br />
practical results <strong>of</strong> the electronics hardware used.<br />
Keywords— Witricity, wireless power transfer, Orcad Pspice<br />
analysis<br />
A. Motivation<br />
I. INTRODUCTION<br />
For the past decade or so there has been a tremendous<br />
growth <strong>of</strong> autonomous electronic devices (such as I-pods,<br />
mobile phones, laptops, PDA etc) which rely primarily on<br />
stored chemical energy for their power needs. If a technology<br />
can be developed to transmit power wirelessly, it will get rid<br />
<strong>of</strong> wire mesh and clutter and portable devices could get<br />
charged wirelessly.<br />
inductive coupling in which the coils need not be in resonance<br />
to exchange energy.<br />
C. Our Approach Vs Existing Approach<br />
Serious research has been going on for the past few years to<br />
develop efficient techniques for transferring power wirelessly,<br />
most notably by the team <strong>of</strong> Kralis <strong>of</strong> MIT and their company<br />
called Witricity (which is a portmanteau for wireless<br />
electricity)[1].However there are a few notable differences<br />
between our approach and the one used by the MIT team.<br />
We have designed the antenna as a single turn coil which<br />
reduces the complexity and cost <strong>of</strong> antennas. Also the whole<br />
prototype including the electronics cointaing the RF Amplifier<br />
has been built indigenously using locally available parts to<br />
ensure minimum costs. Our experimental setup can be<br />
represented by the following diagram.<br />
Wireless power transfer can also be used to power nanodevices<br />
like MEMS and bio-tech devices like pacemakers,<br />
which would prevent the repetitive surgeries a patient needs to<br />
undergo for charging his pacemaker.<br />
The project required an extensive practical and theoretical<br />
knowledge <strong>of</strong> both <strong>Engineering</strong> electromagnetic theory and<br />
analog electronics and thus provided us with a challenging<br />
opportunity to understand these core concepts <strong>of</strong> Electrical<br />
engineering at a much deeper level.<br />
B. Theory<br />
The fundamental physics behind wireless energy transfer is<br />
magnetic resonance. This resonance is similar to the<br />
mechanical resonance which can be easily observed in the<br />
shattering <strong>of</strong> glass experiment. When two coils are in<br />
magnetic resonance, they tend to exchange energy between<br />
themselves while interacting negligibly with Extraneous<br />
objects. Note that the technique is different from simple<br />
Fig. 1 The Prototype setup<br />
Tryst Technical Conference, IIT Delhi 13-14 March, 2010
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