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

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1 MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp ISSN No MIT Publications Polarization Curve/VI Characteristics of Fuel Cell using MATLAB/Simulink Vipul Agarwal Asst. Professor, EED MIT, Moradabad, U.P., INDIA Riturajan Asst. Professor, EED MIT, Moradabad, U.P., INDIA ABSTRACT The use of fast Fourier transform algorithm has developed image processing whereby the twodimensional 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: 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 large sums 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 operation, also they require internal combustion engine (ICE). The main challenge is its proper range selection [8][12], fuel economy 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 fossil fuels and growing air pollution and greenhouse gas emissions, the government agencies and organisations have developed more stringent 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 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 there is no nitrous oxide produced by reactions between the components of the air used in the cell. A fuel cell vehicle could thus be described as zeroemission. Furthermore, because they run off a fairly normal chemical fuel (hydrogen), very reasonable energies can be stored, and the range of fuel cell vehicles is potentially quite satisfactory. They thus offer the only real

2 MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp ISSN No MIT Publications prospect of a silent zeroemission vehicle with a range and performance 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 FCEVS The FCEVs can be considered as series type hybrid vehicles. The design of fuel cell vehicles is quite complex and can vary (b) FCVs with supercapacitors directly connected to fuel cells Direct hydrogen fuel cell vehicles without energy storage The DC/DC converter is not employed to control the DClink voltage. The fuel cell stack voltage is the DClink voltage. This supply system to meet the need of large variations in load power. The fuel cell system has slow response and thus DClink voltage has a large swing. FCVs with supercapacitors directly connected to fuel cells The supercapacitors are directly connected in parallel with the (c) FCVs with energy storage such as supercapacitors or batteries coupled in parallel with fuel cells through a DC/DC converter FCVs with energy storage such as supercapacitors or batteries coupled in parallel with fuel cells through a DC/DC converter The fuel cell voltage is the DClink voltage. The transient power 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 DClink voltage. The steady power provided by the fuel cell passes through the DC/DC converter. The converter regulates the fuel cell power to avoid age. (a) Direct hydrogen fuel cell vehicles without energy storage (d) FCVs with the fuel cell coupled with energy storage unit through a DC/DC converter Fig. 1. Electric Vehicle COMPONENTS OF FCEVS Most of fuel cell vehicles consist of four basic components: 1. A fuel processor. 2. An energy conversion device (fuel cell stack). 3. A current converter. cles for stationary applications). Though most fuel cell vehicles may also include other components and subsystems to control fuel cell humidity, temperature, gas 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 processor may

3 MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp ISSN No MIT Publications of the hydrogen gas. If the vehicle is powered by a hydrogenrich conventional fuel such as methanol, gasoline, diesel, or gasiinto a gas mixture of hydrogen and carbon compounds called V FC (1) E Nest T T (2) 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 chemical reactions that take place in the fuel cell. V act V ohmic i(r M + R C (3) 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 V con C O2 (6) 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. C H2 (7) Heat recovery system Fuel cell vehicles are not primarily used to generate heat. How (8) cell vehicles especially those that operate at high temperatures such as solid oxide and molten carbonate FCs, this excess energy 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 chemical reaction of hydrogen and oxygen, and the only byproducts are water and heat. Recently, much attention has been focused on such fuel cells due to their simple nature as well as environmentally acceptable method of energy transformation as a candidate for near future power generation applications. The accurate mathematical model is a useful tool for simulation and design analysis of fuel cell power systems. The models of PEMFCs can be divided into mechanistic models and semiempirical 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 engineering applications. This semiempirical mathematical model best simulation results. The output voltage of a single cell can 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 the cell, VFC, for a certain operation current. T is the cell temperature (K), PH2 and PO 2 are the pressure (atm) of hydrogen and oxygen, is the concentration 2 of oxygen in the catalytic interface of the cathode (mol/cm 3 ), CH 2 is the concentration of hydrogen in the catalytic interface of the anode (mol/cm 3 ), and A is the cell active area (cm 2 ). The B (V) is a constant depending on the cell and its operation state, the cell (ma/cm 2 ), respectively. RM is the equivalent membrane resistance to proton conduction, and RC is the equivalent contact resistance to electron conduction.

4 MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp ISSN No MIT Publications The equivalent resistance of the membrane RM can be calculated by formula: SE: NaN R M In which l is the thickness of the membrane (cm). The memregistered trademark of DuPont Company and widely used. M Fig. 3: Actual Polarization Curve or V/I Characteristics for Fuel cell For single cells of a fuel cell stack connected in series n, the stack voltage V stack can be calculated by formula (11): V k (11) V stack The ideal V/I characteristics of PEM type Fuel Cell is shown in Fig. 2. Here, f(x) represents voltage as a function of current that means f means voltage and x means current density. 2. ADVANT ANT AGES OF FUEL CELL OVER CONVENTIONAL ENERGY SOURCE They produce zero or very low emissions, especially Green House 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 minimal maintenance, reducing life cycle costs of energy production. Fuel cells can be utilized for combined heat and power purposes, Fig. 2: Ideal PEM Fuel Cell V/I Characteristics The V/I c ting toolbox in Matlab/Simulink environment. FUTURE EXPECTA TIONS OF FCEVS Some experts believe that fuel cell cars will never become economically competitive with other technologies or that it will take Several major car manufacturers have announced plans to inhas stated that it plans to introduce such a vehicle at a price of Hyundai announc ed tha t i t plans to begin producing a commercial

5 MIT International Journal of Electrical and Instrumentation Engineering, Vol. 5, No. 1, January 2015, pp ISSN No MIT Publications REFERENCES Emissions for Conventional Hybrid Electric Vehicles and the UTS IEEE Spectr., vol. 32, no. 7, and FuelCell Vehicles:Architectures and Modeling, IEEE transactions on vehicular technology and Hybrid Energy Storage Systems for Electric, Hybrid Electric, Fuel Cell, and PlugIn Hybrid Electric Vehicles: State of the Art, Hybrid Electric Vehicle Control Strategies for Improved Drivetrain 11. Amirhossein Hajimiragha, Claudio A., Michael W. Fowler, and Ali on Modern Electric, Hybrid Electric, and Fuel Cell Vehicles, CRC in Ontario, Canada, Considering the ElectricityGrid Limitations, IEEE transactions on industrial electronics IEEE International Power Electronics Conference