Research Article Volume 6 Issue No. 4

Transcription

1 DOI / ISSN IJESC Research Article Volume 6 Issue No. 4 Analysis of Dc - Dc Converters for Renewable Energy System P.Janaki 1, Y.Prasanthi 2, S.Vijaya Laxmi 3, B.Narayanamma 4, M.Naveen Kumar 5 Assistant Professor 1 2, 3, 4, 5, UG Scholar Department of Electrical and Electronics Engineering Lendi Institute of Engineering and Technology, Andhra Pradesh, India Abstract:- In general we know that non- renewable sources are non sustainable sources after few years we use renewable energy source only. In our project we are using some renewable energies those are solar energy, wind energy, fuel cell. This project presents the analysis of dc-dc converters for renewable energy system. In this by using the solar and wind we are generating the 220volts power, When these sources are insufficient due to the weather conditions we can get the power by using fuel cell. Fuel cell in which electrolysis take place to generate hydrogen for generation. Now electrolysis is an electrochemical process in which electrical energy is the driving force for chemical reactions. An electrolytic compound is decomposed by passing a current through it. Water is decomposed to hydrogen and oxygen by passing a current through it in the presence of suitable substances called electrolytes. Electric current causes positively charged hydrogen ions to migrate to the negatively charged cathode, where a reduction takes place in order to form hydrogen atoms. The atoms formed will combine to gaseous hydrogen molecules (H2). The most important part in the construction of electrolysis units is to use adequate electrodes to avoid unwanted reactions which produce impurities in the hydrogen gas. By Using fuel cell we generate power for the load where solar and wind energies are used for the constant maintenance of power. In this we are using buck-boost choppers to step up and step down power to desired value. Rectifier converts ac to dc, inverter converts dc to ac for load. In our project we are maintaining constant power at load by using renewable energy. Keywords: DC-DC converters, renewable energy source, regulator, inverter, rectifier. I.INTRODUCTION This paper presents how to maintain a constant power supply by using renewable energy sources. In this project we are using solar,wind and fuel cell energy sources when any one of source is insufficient to maintain constant power supply to the load,alternate sources are used to maintain constant power supply.we can use this industries and domestical. Electrolysis is an electrochemical process in which electrical energy is the driving force for chemical reactions.an electrolytic compound is decomposed by passing a current through it. Water is decomposed to hydrogen and oxygen by passing a current through it in the presence of suitable substances called electrolytes. Electric current causes positively charged hydrogen ions to migrate to the negatively charged cathode, where a reduction takes place in order to form hydrogen atoms. The atoms formed will combine to gaseous hydrogen molecules (H2). On the other hand, oxygen is formed at the other electrode (the positively charged anode). The stoichiometry of the reaction is two volumes of hydrogen to one volume of oxygen. The most important part in the construction of electrolysis units is to use adequate electrodes to avoid unwanted reactions which produce impurities in the hydrogen gas. A. Methods of hydrogen production through water electrolysis Despite the fact in the discovery of electrolytic water decomposing was first observed in acidic water. In industrial plants alkaline medium is preferred because corrosion is more easily controlled and cheaper construction materials can be used for acidic electrolysis technology. Other methods of hydrogen production such as proton exchange membrane electrolysis and steam electrolysis have been developed in recent years. Hydrogen could also be generated as a byproduct during chloralkali production.. The stored hydrogen is fed to a fuel cell to produce electricity. II WORKING OF TYPICAL RENEWABLE ENERGY SYSTEM: The basic model to describe the dynamics of an Renewable energy system with Hydrogen storage(reshs) is shown infig.1. It integrates sub-models of the electrolyser, the fuel cell,the batteries, the power interfaces (buck and boost converters)and the storage system In this we are using the renewable energy sources are wind and the photo voltaic cells. By using these we can generate the electricity. International Journal of Engineering Science and Computing, April

2 buck converter is used to step down the voltage.these to are operated based on the requirement. ELECTROLYSER: Electrolysis process takes place in this electrolyser. By providing energy from a battery, water can be dissociated in to diatomic molecules of hydrogen and oxygen. The hydrogen which is produced from this electrolysis process is stored in the storage. The long-term excess energy with respect to load demand has been sent to the electrolyser for hydrogen production and then the fuel cell has utilized this stored hydrogen to produce electricity when wind and solar energies are insufficient. The DC power required by the electrolyser system is supplied by the DC-DC converter. Electrolysis of water is the best way to produce eco friendly hydrogen because: Fig 1.Block diagram of a typical renewable energy system PHOTO VOLTAICS: Photovoltaic is a marriage of two words: photo, meaning light, and voltaic, meaning electricity. Photovoltaic technology, the scientific term used to describe what we use to convert solar energy into electricity, generates electricity from light. We use a semi-conductor material which can be adapted to release electrons, the negatively charged particles that form the basis of electricity. WIND TURBINES A wind turbine is a rotating machine which converts the kinetic energy in wind into mechanical energy. If the mechanical energy is then converted to electricity, the machine is called a wind generator, wind turbine, wind power unit (WPU), wind energy converter (WEC), or aerogenerator. RECTIFIERS: Rectifiers are used to convert the AC which periodically flows in reverse direction to DC. Which flows only in one direction is known as rectification. In this the rectifiers converts the AC supply which is produced from the wind turbines in to DC. REGULATORS: Regulators are used to regulate the output voltage which is produced from the renewable energy systems. DC TO DC CONVERTERS: DC-DC Converters are developed to maximize the energy harvest for pv system and wind turbines are called power optimizers. The boost converter is used to step up the voltage when the input voltage lower than the output voltage and the (i) Water on earth is abundant (ii) Hydrogen is provided from abundant renewable energy Sources. (iii) Oxidation of Hydrogen for the production of electrical energy (in fuel cells) Produces only water when it is recycled. The stored hydrogen is fed to a fuel cell to produce electricity. FUEL CELL: Fuel cell is a device that converts the chemical enercy from a fuel into electricity through a chemical reaction of positively charged hydrogen ions with oxygen or another oxidizing agent. BATTERIES: The electricity which is produced from these sources are stored in the battery. Here the battery is for storing purpose. INVETERS: Inverters are used for many applications, as in situations where low voltage DC sources such as batteries, solar panels or fuel cells must be converted so that devices can run off of AC power. DC BUS: To ensure a proper flow of power between the system elements, the available energy from different sources are coupled to a low voltage DC bus. A direct connection of DC bus to the electrolyser is not suitable because it lacks the ability to control the power flow between renewable input source and the electrolyser. Therefore, a power conditioning system, usually a DC-DC converter is required to couple the electrolyser to the system bus. High-frequency (HF) transformer isolated, DC-DC converter is suitable for this application due to their small size, light weight and reduced cost. International Journal of Engineering Science and Computing, April

3 III. SIMULATION DIAGRAMS AND RESULTS OF DC - DC CONVERTERS FOR RENEWABLE ENERGY SYSTEM: SUB CIRCUIT: Fig.1 diagram of DC - DC Converters for Renewable Energy System Fig 2: circuit which consists of solar, wind, fuel cell International Journal of Engineering Science and Computing, April

4 Output voltage waveforms: Fig 3: voltage waveform of dc-dc converters for renewable energy system Simulink diagram of solar cell: Fig 4:diagram of solar cell International Journal of Engineering Science and Computing, April

5 Voltage and current waveforms of solar: Fig 5: voltage and the current waveforms of solar Simulink diagram of wind turbine: Fig 6:Diagram of wind turbine voltage and current waveforms of wind turbine: International Journal of Engineering Science and Computing, April

6 Fig 7: voltage and current waveforms of wind turbine Diagram of fuel cell: Fig 8: circuit diagram of fuel cell International Journal of Engineering Science and Computing, April

7 Voltage and current waveforms of fuel cell: Fig 9: Voltage and current waveforms of fuel cell: CONCLUSION: This project presents an analysis of DC-DC Converters for Renewable Energy System here, dc-dc converters are used for step up and step down the voltage.by using solar and wind energy we are generating 220 volts if this sources are insufficient due the weather conditions we can maintain the constant power supply by using fuel cell.the simulation and experimental results show that we are maintaining the constant power to the load. The electrolysis method which increases the hydrogen production and storage rate from wind-pv systems. During periods of excess load demand over the input renewable resources, a fuel cell operating on stored hydrogen would provide a balance of power. By taking sufficient values we get the 220volts constant power to the load. And finally by using inverter we are converting that DC to 230volts AC which will be supplied to the load. systems based on hydrogen for remote applications, Journal of Power Sources 96,2001,pp [5] Menzl F., Wenske M., Lehmann J, Windmillelectrolyser system for a hydrogen based energy supply, in Nummer 2: Regenerative Energien, [6] R.Samuel Rajesh Babu, Joseph Henry comparative analysis of dc-dc converters for renewable energy system REFERENCES: [1] Iwakura C, Tanaka M, Nakamatsu S, Inoue H, Matsuoka M and Furukawa N, Electrochemical properties of Ni/(Ni + RuO2) active cathodes for hydrogen evolution in chlor-alkali electrolysis, Electrochimica Acta 40(8),1995,pp [2] Kreuter W, and Hofmann H, Electrolysis is the important energy transformer in a world of sustainable energy, Int. J. Hydrogen Energy 23(8), 1998, pp [3] Neagu C, Jansen H, Gardeniers H, and Elwenspoek M, The electrolysis of water: An actuation principle for RES, Mechatronics, 2000,pp [4] Agbossou K, Chahine R, Hamelin J, Laurencelle F, Anouar A, St-Arnaud J-M, Bose TK, Renewable energy International Journal of Engineering Science and Computing, April