Contactless energy transfer system
Submitted To:
Submitted By:
Prof. L M Saini
Aditi Goyal
Electrical Electrical Deptt.
Roll No. 107296
NIT Kurukshe Kurukshetra tra
Section Section ± E1
Index Problems
With Conventional Methods
Emergence Different
Ways Of Energy Transfer
Inductive Working Model
Of CEET
Power Transfer
Principle
Of Magnetic System
Simulation
results
Applications Design
methodology
Methods
Of Improving Efficiency
References
Problems associated with the conventional methods
Wear and tear on electrical contacts
Exposure to environmental problems
Around 23% of transmission and distribution losses
Also the technology for alternative sources of energy like solar, wind etc are still considered costly.
Emergence
of CEET
In 1996, Auckland Uniservices developed an Electric Bus power system using electrodynamic induction and Prof. John Boys Team commissioned 1st commercial IPT Bus in New Zealand.
Prof. Marin Solacic, at MIT, wirelessly powered a 60W light bulb with 40% efficiency at 2 meters with two 60 cm-diameter coils.
What
Contactless Energy Tr ansmission Is
Transmission of electrical energy from a power source to an electrical load without interconnecting wires
Large amount of power transmitted is received
Closely related to optimization of transferable power, efficiency and heat development
Elimination of cables, slip rings, plugs and sockets, increasing reliability
Maintenance free operation
Diff er ent Ways
of Energy Tr ansf er
1. Electromagnetic induction A) Electrodynamic induction method B) Electrostatic induction method 2. Electromagnetic radiation A) Microwave method B) Laser method 3. Electrical conduction
Electromagnetic Electrodynamic
Induction
induction method
This wireless transmission technique is near field over distances up to about one-sixth of the wavelength used. Near field energy itself is non-radiative but some radiative losses do occur. In addition there are usually resistive losses.
Electric current flowing through a primary coil creates a magnetic field that acts on a secondary coil producing a current within it.
Inductive coupling allows power transfer from few mW up to hundred KW
Electrostatic
Induction Method
Electrostatic or capacitive coupling is the passage of electrical energy through a dielectric
The capacitive coupling is used in low power range (sensor supply systems)
The electric field is created by an alternating current of high potential and high frequency
Electromagnetic
r adiation
Microwave method
More directional power transmission via radio waves, allowing longer distance power beaming, with shorter wavelengths of electromagnetic radiation.
A rectenna is used to convert the microwave energy back into electricity having efficiency greater than 95%
Laser method
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
Also known as power beaming
Advanta ges
no radio-frequency interference to existing radio communication
control of access; only receivers illuminated by the laser receive power
compact size of solid state lasers
Disadvanta ges
Conversion to light, such as with a laser, is inefficient.
Conversion back into electricity is inefficient, with photovoltaic cells achieving 40%-50% efficiency
Atmospheric absorption causes losses.
As with microwave beaming, this method requires a direct line of sight with the target
Electrical
Conduction
Actual displacement of charge through earth and atmosphere.
Low frequency alternating current transmitted through earth with low loss because the net resistance of earth is less than 1 ohm.
Electrical conduction through atmospheric strata is made possible by the creation of discharge plasma through the process of atmospheric ionization.
Working
Principle Of IPT
Consists of magnetically coupled transmitter coil L1 and a receiver coil L2
Alternating current in transmitter coil generates magnetic field inducing voltage in the receiver coil
Efficiency depends on the coupling (k) between the inductors and their quality (Q)
Model Of Magnetic System
The inductances L(h), L1 and L2 can be obtained by means of a magnetic flux simulation. The inductances can be calculated as described in the following equations:
L(h): main inductance R1, R2: ohmic resistances R(L): secondary load resistance L1, L2: leakage inductances
Results
of simulation
Variation of main inductance with air gap
Variation of output power and efficiency with load r esistance
Variation of output power with air gap length
Variation of output power with tr ansmission fr equency
Applications
Powering the Home
Wireless Charging
Defence
Space based Solar Power
Transport
Por table phone battery Charger
Design
Methodology
Methods of improving efficiency
Leakage
inductance compensation method
Realized by a parallel resonance capacitor or series resonance capacitor at secondary coil
Use Of ferrite cores
improves the magnetic characteristics.
Increases transferable electrical power and efficiency
Conclusion Thus we have seen that wireless energy transmission has improvements over the conventional ones. An efficiency greater than 90 % can be realized by using this system. A lot of study is being done in this field. It finds application in many fields like spacecraft propulsion, battery charging and defence. Thus this technology used in combination with the conventional methods can lead to an effective and efficient system.
Ref er ences Modelling
and design of a contactless energy transfer system for a notebook battery charger Pascal Meyer, Paolo Germano and Yves Perriard Eßer, A.; Nagel, A.: Contactless high speed signal transmission integrated in a compact rotatable power transformer. European Conference on Power Electronics and Applications, Brighton 1993, Vol. 4, pp 409-414 Green, A. W.; Boys, J. T.: 10 kHz inductively coupled power transmission ± concept and control. International Conference on Power Electronics and Variable Speed Drives, London 1994, pp 694-699 Knaup, P.; Hasse, K.: Zero voltage switching converter for magnetic transfer of energy to movable systems. Hayes, J. G.; Hall, J. T.; Bellino, G.; Conroy, K.: Off-board incuctive charging for the Genaral Motors EV1electric vehicle.
