International Journal of Engineering Trends and Technology (IJETT) – Volume 21 Number 3 – March 2015
Design of Wireless Power Transfer System for
Electric Vehicles
Kalyani Ghate1, Lalit Dole2
1
M.E. Embedded System and Computing, Department of Computer Science and Engineering, G. H. Raisoni College of
Engineering, Nagpur, Maharashtra, India
2
Assistant Professor, Department of Computer Science and Engineering, G. H. Raisoni College of Engineering, Nagpur,
Maharashtra, India
Abstract— Vehicles are the main fossil fuel consumers. To
reduce environmental pollution, Electric vehicle technology has
been developed. This electric vehicle considered to be most
suitable alternative of petroleum vehicles. Electric vehicle include
plug and play and battery operated electric vehicle. To charge
this electric vehicle conventional method of charging is used,
Such that we have to plug the vehicle into standard socket and
charge the vehicle. But if we have to travel long distance this
method of charging defeat. This method of charging does not
solve the problems related to driving range, long charging time,
battery related drawbacks etc. This paper gives how battery is
charged with the help of wireless transfer technology. Proposed
concept used magnetic resonance based wireless electric vehicle
charging.
Keywords— Petroleum vehicle, Driving range, Electric vehicle,
Fossil fuels, Wireless power transfer system.
I. INTRODUCTION
Nowadays wireless technology has been getting a lot of
attention. It is considered as the boon for today’s technology.
Wireless energy transmission can be considered as transfer of
electrical energy from power source to electrical load [6]. The
concept of resonant magnetic induction is used to carry out
wireless power transmission. Resonance inductive coupling
systems are means of transferring power without mechanical
contact. They have found in various applications in monorail,
automated guided vehicle, battery charging. The advantage of
this system is that it is completely cleaned, safe and
environmentally robust.
The issues like greenhouse effect, emission of various
gases, decreasing petroleum resources are global problem.
Vehicles are considered to be more fossil fuel consumers. To
solve this problem in transportation areas manufacturers are
developing green bus, hybrid vehicle, electric vehicles etc.
However these vehicles are not distributed widely, because of
long charging time, shorter driving range, expensive price etc.
Electric vehicle first came into existence in the mid-19th
century. All electric such as battery operated electric vehicles
are distributed narrowly. As we know generally to charge this
electric vehicle ―conductive charging‖ method is used, means
we have to plug the cable of electric vehicle into dedicated
circuit n have to charge the vehicle. This charging method is
very easy not extra effort required and also helpful in saving
the petroleum resources. But if we want to travel long journey,
after covering particular distance we want to charge that
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vehicle. In between roadway every time standard socket is not
available to charge the vehicle.
To eliminate this type of drawback ―inductive charging‖
method is very helpful. In this method with the help of
magnetic coupling vehicle is charged on the roadway. It
eliminates cable connection. If we want to charge the vehicle
we have to just park the vehicle in particular track which
contain setup of charging, only care taken while charging is
that vehicle should be aligned parallel to that track so that
maximum amount of power delivery occurs.
The related work about the previous research is explained
in section II. Section III describes the concept of magnetic
resonance. Section IV describes the principles of inductive
coupling, Section V gives proposed method and section VI
gives the conclusion
II. RELATED WORK
Plug-in method is used to charge an electric vehicle.
Paper [1] explains the concept of how moving electric
vehicles are charged wirelessly through an example of an
online electric vehicle system. Here by using wireless power
transfer technique electric vehicle is charged on road itself.
But practically implementation cost is very high, here inverter
receives power from an electric power company and also if
battery is fully charged then also charging is provided for that
vehicle while moving on the road.
In paper [2], the author described decentralized way of
charging to allow individual plug in electric vehicle to
determine their own charging pattern. To control the large
population of electric vehicle they give the concept of Nash
Equilibrium. Paper only included two user preferences to
minimize local electricity cost and fully charge.
Concept of inductive coupling is used for wireless power
transfer. Paper [3], [4], [5] present the analysis of two loosely
coupled coils used to transfer energy to charge battery.
Loosely coupled coils are considered, the maximum power
transfer efficiency of coupled coils. It gives how power is
transfer using magnetically coupled coils and is carried out
such that maximum efficiency is achieved. Inductive coupling
is nothing but it consist of two loosely coupled coils,
according to amperes law we know that when a current flow
through any conductor a circular magnetic field is formed
around the conductor. Inductively coupled power transfer
system is designed [6] to deliver power efficiency from
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International Journal of Engineering Trends and Technology (IJETT) – Volume 21 Number 3 – March 2015
stationary primary side to one or more movable secondary
load via magnetic coupling.
The authors in [7] analysed the relationship between
maximum efficiency air gap using equivalent circuit and
Neumann formula. They set up an equivalent circuit which
consists of helical antennas both on transmitting and receiving
sides. Set up consist of vector network analyser is used to
measure transmission and reflection ratio of system. Number
of turns in the antenna is one and capacitor is installed in
series with antenna. All set up is connected with table and
distance is varied. In [8] authors compared the 3 generation of
on line electric vehicle, In this paper author estimate that if the
air gap between the two coils is maximum then less power is
transmitted, they try to eliminate this drawback with the help
of different core structure.
In paper [9], authors present the optimized design of an
ICPT system. The authors explain the parameters require
designing ICPT system such as winding dimensions, supply
voltage, power to be transferred to load. They shows various
topologies and design such that compensation capacitance and
quality factor can be determined. With the help of this various
designs they concluded that it is possible to deliver maximum
power with high efficiency.
In [10] author proposes two different types of core shape
analysis for contactless transformer, which can be used for
delivering high power to traction in new railway system.
Railway system without catenary can solve construction cost
and maintenance cost. [11] This paper presents a new pickup
configuration that improves the power profile of pick up
relative to track, [12] concept of inductive power transfer
system is used to design the contactless battery charger for
cellular phone. The same concept of inductive coupling is
going to use while charging the battery of electric vehicle , we
are trying to develop the cost effective system instead of
using electricity from the power grid we are generating
electric energy with the help of solar panel. So we are going to
develop the simplified structure of roadway power electric
charging system.
III. MAGNETIC RESONANCE
Magnetic resonant inductive coupling or electrodynamics
induction is the near field wireless transmission of electrical
energy between two magnetically coupled coils that are part
of resonant circuits tuned to resonate at same frequency.
Magnetic resonance coupling being used in wireless power
systems. Here the two LC circuits are in different devices, a
transmitter coil in one device transmits electric power across
an inverting space to a resonant receiver coil in another device.
This technology is being developed for powering and charging
portable devices such as cell phones and tablet computers at a
distance without being tethered to an outlet.
Resonant transfer works by making a coil ring with an
oscillating current. This generates an oscillating magnetic
field. Because the coil is highly resonant, any energy placed in
the coil dies away relatively slowly over many cycles, but if a
second coil is brought near it, the coil can pick up most of the
energy before it is lost; even it is some distance away. The
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fields used are predominately near fields as all hardware is
kept well within the ¼ wavelength distance they radiate little
energy from the transmitter to infinity.
IV. PRINCIPLES OF INDUCTIVE COUPLING
Figure shows the circuit of inductive coupling. This circuit
is fundamentally the same as the circuit model of transformer
Fig. 1 Inductive coupling [1]
It consist of transmitter coil L1 and receiver coil L2. When
an alternating current flows through the transmitter coil it
generates a magnetic field, which creates a voltage in the
receiver coil. Hence battery is charged with the help of this
voltage. The efficiency of the power transfer depend on the
coupling (k) between the inductor and their quality.
Electromagnetic coils are used in applications where electric
current interact with magnetic field. We are going to use this
concept while charging the electric vehicle.
V. PROPOSED METHOD
Our system consists of three parts such as Transmitter,
platform and Receiver. Transmitter part is built on the roadway,
Platform is nothing but the track where electric vehicle is park,
and receiver part is vehicle.
A. Transmitter
Transmitter part consists of Solar panel, voltage ripple
circuit, battery (12v). Solar panel is a set of photovoltaic cells
electrically connected and mounted on a supporting structure;
voltage ripple circuit is used to remove ripples and 12v battery
to store the charging.
Fig. 2 Transmitter part
B. Platform
Platform is also called as track. It consist of filter-oscillator
circuit,the main function of filter is to remove unwanted ripples
and oscillator circuit is used to convert direct current into
alternating current (D.C.- A.C.) and magnetic coil 1 which is
deployed into track.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 21 Number 3 – March 2015
Fig. 3 Platform part
C. Receiver
Receiver circuit is the electric vehicle. At the base portion
of electric vehicle magnetic coil 2 is connected and the
connection is made as shown in following block diagram.
used such that plug and play method of charging; this method
of charging fails if driving range distance is large. To make a
system smart and innovative wireless power energy concept is
indeed a great and noble one. In this paper we studied
inductive method of charging, proposed concept gives how
electric vehicle is charge wirelessly. Roadway power system
is nothing but the transmitter or source battery is charged at
the roadway, the vehicle which needs charging will park his
vehicle on the track, when two magnetic coils come closer
battery is charged with the help of magnetic resonance
concept. To recover the disadvantage like long charging time
and short driving range, the charging of an electrical vehicle
wirelessly will be more significant and will help to remove
some sort of drawbacks. Hence these concepts help us to
achieve a wireless power electrical vehicle system.
REFERENCES
[1]
[2]
Fig. 4 Receiver part
[3]
D. Overall Circuit
Block diagram is as shown figure below,by combining
transmitter, platform and receiver part it help us to achieve
wireless charging of electric vehicle.
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
Fig. 5 Block diagram of overall circuit
System require good horizontal and vertical alignment
beteen vehicle pickup module and track to ensure large amout
of power delivery
VI. CONCLUSIONS
Various techniques are available to charge the electric
vehicle. Conventionally conductive method of charging is
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