Hi, here is one of my base research on wireless system , transmitting of power wire-less. This Post enables you to understand what basically wireless power transmission means , who provoked it and how to design a wireless charging system for your low power devices like mobile, mp 3 player, iPod and lightning system.
History:
The history of wireless power transmission dates back to the late 19th century with the prediction that power could be transmitted from one point to another in free space by Maxwell in his “Treatise on Electricity and Magnetism”. Heinrich Rudolf Hertz performed experimental validation of Maxwell’s equation which was a monumental step in the direction. However, Nikola Tesla’s experiments are often considered as being some of the most serious demonstrations of the capability of transferring power wire-lessly even with his failed attempts to send power to space
Wireless Power Transmission (WPT) :
Wireless power transmission is the transmission of electrical energy from a power source to an electrical load without interconnecting wires. This Wireless Transmission is useful in cases where interconnecting wires are inconvenient, hazardous, expensive or impossible. With wireless power, the efficiency is the more significant parameter. A large part of the energy sent out by the generating plant must be optimally received at the end. They can be categorized as:
- Near field
- Mid field
- Far field
Based on the mode of coupling between the transmitter and the receiver, wireless power transfer techniques can be classified into the following:
- Electromagnetic induction (Resonant Inductive Power Transfer)
- Electrostatic induction (Resonant Capacitive Power Transfer)
- Far field transfer techniques (Laser and Microwave Power Transfer)
from the above classification Electromagnetic Inductive Power Transfer (IPT) is a popular technique of transferring power wire - lessly over a short range. Thus we are going to use the same technique for our design ,this technique of transferring power derives its capability from the two fundamental laws of physics: Ampere’s law and Faraday’s law.
DESIGN :
To start with our design we need to know what all the basic models in WPT system, they are
- High frequency generator
- Transmitter and Receiver coil
- Voltage Regulator
High Frequency generator - To transmit power wire-less we have to know the frequency range of it, our application (short range transmission) the frequency range is around 1 to 10 MHz. To generating this high frequency we can use oscillator circuits. For my design i used colpitt oscillator,as the circuit diagram and simulation are shown below.
Fig : General Colpitt oscillator circuit
Fig: Colpitt Oscillator Simulation - High frequency generator
Transmitter / Receiver Coil: The challenge of WPT depends on this modules like shape (rectangle / circle), turns , size and stacking . The below figure shows the various shape of Tx and Rx coils used for testing WPT.
Fig: Tx and Rx coil different shape, turn and size
Fig: Test setup determine the induced voltage
Test Procedure:
- System contains Signal generator , Tx coil , Rx coil and CRO.
- Signal Generator is used to vary the Sine Input voltage and frequency in Tx side.
- An sinusoidal input of 250kHz to 2MHz applied to the transmitter coil and it’s respective induced receiver coil voltage has been measured. Graph has been plotted with respect to Input frequency Vs Inducted voltage .
- Tx and Rx coil inductance values have been changed and induced voltage has been measure.
- Various Shape of the Tx and Rx coil has been checked.
Fig: Frequency Vs Induced voltage w.r.t shape
Fig: Plot to find the efficiency w.r.t to shape
WPT SYSTEM :
From the Simulation and experiment result we are able to design the hardware configuration of our WPT. The below figure shows the prototype module designed and tested with Nokia mobile. This model is also tested with various mobiles (Samsung, Videocon and nokia models) whose battery curret rating various up to 1500 mAh.
Fig: Prototype model of WPT - Mobile charging
References:
- “Numerical Analysis on Transmission Efficiency of Evanescent Resonant Coupling Wireless Power Transfer System”, Qiaowei Yuan, Qiang Chen, Member, IEEE, Long Li, and Kunio Sawaya, Senior Member,IEEE – 5th May 2010.
- Zhuo Yan, Haiyan Chen, Qingxin Yang, Chao Zhang, Guizhi Xu Province,Ministry Joint Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability, Hebei University of Technology - 2010.
- “Research on the Model of Magnetic-Resonance Based Wireless Energy Transfer System” Chunlai Yu, Rengui Lu, Yinhua Mao, Litao Ren, Chunbo Zhu School of Electrical Engine ering and Automation, Harbin Institute of Technology, Harbin, China – 2009,
- “Wireless power transmission in the Smart Home”,Yin Quan Teo , Dr.Mathew S. Reynolds.
- “An RFID-Based Closed-Loop Wireless Power Transmission System for Biomedical Applications”, Mehdi Kiani, Student Member, IEEE, and Maysam Ghovanloo, Member, IEEE
