Solar Energy – Future of Rural India

Solar technologies allows to harness sun’s energy for immediate use. Solar energy can be stored as heat and the sun’s light can be used to generate electric power for home or business. This paper provides designing of an inverter that will enable the inversion of a DC power source, supplied by Photovoltaic (PV) Cells, to an AC power source that will be used to supply a load even without working main supply.

Introduction

To generate electrical power conventional sources like coal, gas, nuclear power generators are used. Some of the conventional sources pollutes the environment to generate the electricity and nuclear energy is not preferable because of its harmful radiation effect on the mankind. After ten years, conventional sources will not be sufficient enough to fulfill the requirements of the mankind. So in today's time of growing energy needs and increasing environmental concern, alternatives to the use of non-renewable and polluting fossil fuels are investigated. One such alternative is solar energy.

Solar energy is simply the radiant energy in form of light and heat energy, emitted by the sun. The sun creates its energy through a thermonuclear process that converts about 650,000,000 tons of hydrogen to helium every second. The process creates heat and electromagnetic radiation. A small fraction of the total radiation produced reaches the Earth. The radiation that does reach the Earth is the indirect source of nearly every type of energy used today. This solar energy in form of radiation can be directly converted to electricity. Most of our tools are designed to be driven by electricity, so if we can create electricity through solar power, we can run almost anything with solar power. So we use solar collectors that can convert this radiation to electricity that can be used for various loads even in absence of main supply. Due to the nature of solar energy, two components are required to have a functional solar energy generator i.e. in addition to a collector, a storage unit is also incorporated in the system. The collector simply collects the radiation that falls on it and converts a fraction of it to other forms of energy either electricity and heat or heat alone. The storage unit is required because of the variable nature of solar energy.

Components of Solar conversion:

Photovoltaic Cells

A photovoltaic cell is basically a semiconductor diode that convert visible light into direct current (DC). Some PV cells can also convert infrared or ultraviolet radiation into DC electricity. This phenomenon has been known for well over half a century, but until recently the amounts of electricity generated were good for little more than measuring radiation intensity. Basic mechanism of a photovoltaic (PV) cell is shown in the diagram where production of electricity from a single PV cell is shown in fig.1.

PV cells are an integral part of solar-electric energy systems, which are becoming increasingly important as alternative sources of utility power. Most of the photovoltaic cells on the market today operate at an efficiency of less than 15%; that is, of all the radiation that falls upon them, less than 15% of it is converted to electricity.

Solar inverter

An inverter is an electrical device that converts direct current (DC) to alternating current (AC), the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits.

Solid-state inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries. The inverter performs the opposite function of a rectifier.

The Solar Inverter is an essential device in any solar power system. Its basic function of the inverter is to change the variable Direct Current output of the solar panels into Alternating Current. The various electrical and electronic components connected in the circuit help in the conversion. The converted Alternating Current power is used for running y appliances like the TV, Refrigerator, Microwave, etc. For some particular applications, we can directly use the Direct Current power from the solar panel such as LED night lights, a cell phone charger. Generally, the power of a home solar power system is used for power AC loads. In the model presented in this paper we are using both ac and dc loads on small scale like fan and bulbs.

Advantages of Solar Inverter

Solar energy has constantly helped in decreasing the greenhouse effect and global warming.

• By using of solar based devices will help in saving money and also energy. Because many people have started using these devices.
• A solar inverter helps in changing the DC into batteries or AC. This supports people who use a partial amount of electricity.
• The synchronous solar inverter that helps small homeowners and also power companies as they are huge in size.
• The multifunction solar inverter is the finest among all and works powerfully. It converts the DC to AC very carefully which is suitable for commercial establishments.
• This inverter is cost effective, i.e. low cost than generators.
• Apart from these there are additional devices too, that make use of solar energy such as, solar heater, cooker.

Disadvantages of Solar Inverter

• Primarily, we need to shell out a lot of money for purchasing a solar inverter
• It will work efficiently and produce DC only when the daylight is strong.
• The solar panels are used to attract the sunshine needs lots of space
• Solar Inverters can work when there is no Sunshine but the battery which is available in that is charged fully with the help of Sunshine.

With the rapid progress of the power electronic techniques, solar energy as an alternative energy source has been put to use such as photovoltaic (PV) module. The basic concept for PV module is to collect solar energy in space and transfer it for distribution as electrical power. However this renewable source energy requires rather sophisticated conversion techniques to make them usable to the end user. The output of PV is essentially direct current (DC) form. Therefore, it needs to be converted to alternating current (AC) for it to be commercially feasible. This is necessary because the power utilization is mostly in AC form. This conversion can be done by using inverter. In any PV based system, the inverter is a critical component responsible for the control of electricity flow between the modules, battery and loads. Inverters are essentially DC-AC converters. It converts DC input into AC output. It can be designed to be used with different voltage ranges and topologies for varying applications A solar inverter takes the DC electricity from the solar array and uses that to create AC electricity.

Hardware Components:

1. The simplest semiconductor device is made up of a sandwich of P-type semiconducting material, with contacts provided to connect the p-and n-type layers to an external circuit. This is a junction Diode. If the positive terminal of the battery is connected to the p-type material (cathode) and the negative terminal to the N-type material (Anode), a large current will flow. This is called forward current or forward biased. Thus the Diode allows direct current to pass only in one direction while blocking it in the other direction.
2. 555 TIMER a 8-PIN TIMER, use as in 1 & 5, 4 & 8, are short circuited in our model. The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator.
3. The metal–oxide–semiconductor field-effect transistor (MOSFET) is a type of field-effect transistor (FET). It has an insulated gate, whose voltage determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals.
4. A printed circuit board (PCB) mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components (e.g. capacitors, resistors or active devices) are generally soldered on the PCB.
5. Solar panel – A solar panel (also solar module, photovoltaic module or photovoltaic panel) is a packaged, connected assembly of solar cells, also known as photovoltaic cells. The solar panel can be used as a component of a larger photovoltaic system to generate and supply electricity in commercial and residential applications. Because a single solar panel can produce only a limited amount of power, many installations contain several panels. A photovoltaic system typically includes an array of solar panels, an inverter, and sometimes a battery and interconnection wiring.

Applications

Solar inverter has many advantages but also few disadvantages, it requires management too for its proper functioning. The presented model in this paper is a basic model which can be easily made and can be easily installed even in remote areas where main supply may not be available. The capacity of the model presented can be modified in accordance with the required application. Though installation cost is high but in long run it is a cheap source of energy. Recently in India some celebrities pledged for the development of remote areas, the model presented can be used in these areas for the development. The installation and usage of this model is easy and understandable even if the operating person has no technical knowledge, only the person installing this has to teach them certain points about this model and then they are good to go.

Conclusion

Solar power production is gaining more significance as a renewable energy source due to its many advantages. These advantages include everlasting pollution free energy production scheme, ease of maintenance, and direct sunbeam to electricity conversion. However the high cost of PV installations still forms an obstacle for this technology. Moreover the PV panel output power fluctuates as the weather conditions, such as the insolation level, and cell temperature that is why a battery is incorporated in the model presented. The described design of the system will produce the desired output of the project. The inverter will supply an AC source from a DC source. The project described is valuable for the promising potentials it holds within, ranging from the long run economic benefits to the important environmental advantages. This work will mark one of the few attempts and contributions in the Arab world, in the field of renewable energy; where such projects could be implemented extensively. With the increasing improvements in solar cell technologies and power electronics, such projects would have more value added and should receive more attention and support.

Future scope

Today the global warming and energy crisis are major issues that needs to be resolved our project will help in this field using solar energy to generate electricity. Solar energy is a renewable source of energy which is why main aim of our project is to promote use of renewable energy sources. This project is very useful in our life because in this project one time investment fixed on life time. In future one day nonrenewable energy will end then use of the renewable energy will be required. The solar inverter made using 555 timer is just a prototype for making future projects which incorporate advanced technologies like micro controlled solar tracking, charge control, etc. this is to show that solar inverters are very cheap and easy to install so that the energy demands are shifted on using renewable sources of energy. There is more advancements pending in this field which will revolutionize the energy stream and solar energy will be playing the most important role of all.