MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp. 20-24 20

Polarization Curve/VI Characteristics of Fuel Cell using MATLAB/Simulink

Vipul AgarwalAsst. Professor, EED

MIT, Moradabad, U.P., INDIA

RiturajanAsst. Professor, EED

MIT, Moradabad, U.P., INDIARiturajan11@gmail .com

INTRODUCTION

An electric vehicle is an automobile that is propelled by one electric motor or more, using electrical energy stored in fuel cells/batteries or another energy storage device. A hybrid vehicle drive

For the purpose of recapturing part of the braking energy that is dissipated in the form of heat in conventional ICE vehicles, a hybrid drive train usually has a bidirectional energy source and converter. The other one is either bidirectional or unidirectional.

really make their mark as a power source for electric vehicles. Most of the major motor companies are spending very largesums of money developing fuel cell powered vehicles. In HEVs & FCEVs, there are more electrical components are used like electric motor, power electronics converters, batteries, stack of fuel cells, ultra capacitors, sensors and controllers for its opera-tion, also they require internal combustion engine (ICE). The main challenge is its proper range selection [8][12], fuel economy

HISTORY OF FCEVS

the Fuel Cell”) discovered that it might be possible to generate electricity by reversing the electrolysis of water, but it was not so successful because the electricity was not known enough. In

fuel cell using air and coal gas.

and nickel electrodes. Due to a some of technical problems, it

NEED OF EVS, HEVS AND FCEVS

With the rapidly increasing population, energy consumption in the world, increasing oil and natural gas prices, depletion of fossilfuels and growing air pollution and greenhouse gas emissions, the government agencies and organisations have developed morestringent standards for the fuel consumption and emissions,thus the need of battery powered vehicles or fuel economic and reduced emission vehicles is felt & EVs, HEVs and FCVs are found to be the most suitable alternate to meet the requirements.

Why FCEVs?

Fuel cell uses hydrogen fuel to produce electricity, the product is thus water and energy. Because the types of fuel cell likely to

there is no nitrous oxide produced by reactions between thecomponents of the air used in the cell. A fuel cell vehicle could thus be described as zero-emission. Furthermore, because they run off a fairly normal chemical fuel (hydrogen), very reason-able energies can be stored, and the range of fuel cell vehicles is potentially quite satisfactory. They thus offer the only real

ABSTRACT

The use of fast Fourier transform algorithm has developed image processing whereby the two-dimensional Fourier transform of an image is transmitted over a channel rather than the image itself. The development of further encoding techniques leads in further compression of data. The Hadamard matrix is a square array of plus and minus ones whose rows and columns are orthogonal to each other. In Hadamard transformation only real number sum and multiplication is done so it is very easy and speed of transformation increases compared to other transformations like fourier transformation.Keyword:

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MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp. 20-24VV 21

prospect of a silent zero-emission vehicle with a range andperformance broadly comparable with ICE vehicles. It is not surprising then that there have, for many years, been those who have seen fuel cells as a technology that shows great promise, and could even make serious inroads into the domination of the internal combustion engine.

ARCHITECTURE OF FCEVARCHITECTURE OF S

The FCEVs can be considered as series type hybrid vehicles. The design of fuel cell vehicles is quite complex and can vary

Direct hydrogen fueff l cell vehicles without energystorage

The DC/DC converter is not employed to control the DC-link voltage. The fuel cell stack voltage is the DC-link voltage. This

supply system to meet tt he need of large variations in load power.The fuel cell system has slow response and thus DC-link voltagehas a large swing.

FCVs with supercapacitors directly connected to fuel cells

The super-capacitors are directly connected in parallel with the

FCVs with energy storage such as super-capacitors orbatteries coupled in parallel with fuel cells through a DC/DC converter

The fuel cell voltage is the DC-link voltage. The transientpower provided by the energy storage is regulated by a DC/DC converter.

FCVs with the fuel cell coupled with energy storage unit through a DC/DC converter

The energy storage voltage is the DC-link voltage. The steady power provided by the fuel cell passes through the DC/DCconverter. The converter regulates the fuel cell power to avoid

age.

(a) Direct hydrogen fuel cell vehicles without energy storage

(b) FCVs with super-capacitors directly connected to fuel cells

(c) FCVs with energy ener storage such as super-capacitors or batteriescoupled in parallel with fuel cells through a DC/DC converter

(d) FCVs with the fuel cell coupled with energy storage unit through a DC/DC converter

Fig. 1.Electric Vehicle VV

COMPONENTS OF FCEVCOMPONENTS OF S

Most of fuel cell vehicles consist of four basic components:

1. A fuel processorA .

2. An energy conversion device (fuel cell stack).

3. A current converterA .

-cles for stationary applications).

Though most fuel cell vehicles may also include other compo-nents and subsystems to control fuel cell humidity, temperature, humidityhumiditygas pressure and waste water.

Fuel Processor

The fuel processor converts fuel into an adaptable form needed by the fuel cell. If hydrogen is fed to the vehicle, a procee, a ssor may

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VFC

…(1)

ENest

T T …(2)

Vact

…(3)

Vohmic

i(RM + R

C

Vcon

CO2

…(6)

CH2

…(7)

…(8)

In these equations, ENernst is the thermodynamic potential of

drop resulted from the activation of the anode and of the cathode

(Ohmic over potential), associated with the conduction of the

and Vcon represents the concentration drop which is resulted from the decrease in the concentration of oxygen and hydrogen (concentration overpotential). This voltage drop is modeled

to the main FC current density, even when the FC is operated

PEMFC operation open circuit voltage (without load), while the three last terms represent reductions in this output voltage for thecell, VFC, for a certain operation current. T is the cell temperature(K), PH2 and PO

2 are the pressure (atm) of hydrogen and oxygen,

2 is the concentration

of oxygen in the catalytic interface of the cathode (mol/cm3), CH

2 is the concentration of hydrogen in the catalytic interface

of the anode (mol/cm3), and A is the cell active area (cm2). The B (V) is a constant depending on the cell and its operation state,

the cell (mA/cm2), respectively. RM is the equivalent membraneresistance to proton conduction, and RC is the equivalent contactresistance to electron conduction.

of the hydrogen gas. If the vehicle is powered by a hydrogen-richconventional fuel such as methanol, gasoline, diesel, or gasi-

into a gas mixture of hydrogen and carbon compounds called

Energy conversion device – the fuel cell stack

The fuel cell stack is the energy conversion device. It generates electricity in the form of direct current (DC) from chemicalreactions that take place in the fuel cell.

Current inverters and conditioners

The purpose of current inverters and conditioners is to adapt the electrical current from the fuel cell to suit the electrical needs of the application grid. Fuel cells produce electricity in the form of direct current (DC). If required the direct current will have to be converted to alternating current by using converter conveniently.Both AC and DC power must be conditioned. Power conditioning

characteristics of the electrical current to meet the needs of the application. Thus the current converter and conditioner both are used to attain the compatibility.

Heat recovery system

Fuel cell vehicles are not primarily used to generate heat. How-

cell vehicles especially those that operate at high temperatures such as solid oxide and molten carbonate FCs, this excess en-ergy can be used to produce steam or hot water or converted to electricity via a gas turbine or other technology. This increases

POLARIZATION CURVE OF FCEVS

Polymer electrolyte membrane fuel cells are advanced energy conversion devices that produce electricity through the chemicalreaction of hydrogen and oxygen, and the only by-products are water and heat. Recently, much attention has been focused on such fuel cells due to their simple nature as well as environmen-tally acceptable method of energy transformation as a candidate for near future power generation applications. The accuratemathematical model is a useful tool for simulation and design analysis of fuel cell power systems.

The models of PEMFCs can be divided into mechanistic modelsand semi-empirical models. The mechanistic models are based

-tions and always have more details, requiring the knowledge

empirical models are easier to be obtained and can also be used to accurately predict the fuel cell system performance for engi-neering applications. This semi-empirical mathematical model

best simulation results. The output voltage of a single cell can

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MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp. 20-24VV 23

The equivalent resistance of the membrane RM can be calculatedby formula:

RMM

In which l is the thickness of the membrane (cm). The mem-

registered trademark of DuPont Company and widely used.

M

-

For single cells of a fues of a l cell stack connected in series n, thes n, ts n, t stackvoltage V

stack can be calculated by formula (1

stack1):

Vstack

Vstack

…(11)

The ideal V/I characteristics of PEM type Fuel Cell is shown in Fig. 2.

Fig. 2: Ideal PEM Fuel Cell V/I Characteristics

The V/I c -ting toolbox in Matlab/Simulink environment.

SE: NaN

Fig. 3: Actual Polarization Curve or V/I Characteristics for Fuel cell

Here, f(x) represents voltage as a function of current that means f means voltage and x means current density.

2.

ADVANTADVADV AGES OFANTANT FUELAGES OF CELL FUEL OVER CELLCONVENTIONAL ENERGYCONVENTIONAL SOURCE ENERGY

They produce zero or very low emissions, especially GreenHouse Gases (GHGs) depending on the fuel used.

-ventional power systems such as the internal combustion engine.

Fuel cells have few moving parts and thus require minimalmaintenance, reducing life cycle costs of energy production.

-

Fuel cells can be utilized for combined heat and power purposes,

FUTURE EXPECTAFUTURE EXPECTFUTURE EXPECT TIONS OFAA FCEVTIONS OF S

Some experts believe that fuel cell cars will never become eco-nomically competitive with other technologiesor that it will take

Several major car manufacturers have announced plans to in-

has stated that it plans to introduce such a vehicle at a price of

Hyundai announc a a ed thad td t t it t plt ans taa o begin producing a cng a ommercial

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REFERENCES

IEEE Spectr., vol. 32, no. 7,

and Hybrid Energy Storage Systems for Electric, Hybrid Electric, Fuel Cell, and Plug-In Hybrid Electric Vehicles: State of the Art”,

on Modern Electric, Hybrid Electric, and Fuel Cell Vehicles”, CRC

Emissions for Conventional Hybrid Electric Vehicles and the UTS

and Fuel-Cell Vehicles:Architectures and Modeling”, IEEEtransactions on vehicular technology

Hybrid Electric Vehicle Control Strategies for Improved Drivetrain

11. Amirhossein Hajimiragha, Claudio A., Michael W. Fowler, and Ali

in Ontario, Canada, Considering the Electricity-Grid Limitations”, IEEE transactions on industrial electronics

IEEE International Power Electronics Conference

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