1.0     Introduction

Solar inverter converts direct current (DC) output of a photovoltaic (PV) solar panel into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or used by a local, off-grid electrical network. It is a critical balance of system (BOS)–component in a photovoltaic system, allowing the use of ordinary AC-powered equipment. Solar power inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection.

The solar panel used in solar inverter produces direct electricity with the help of electrons that are moving from negative to positive direction. Most of the appliances that we use at home work on alternative current. This AC is created by the constant back and forth of the electrons from negative to positive. In AC electricity the voltage can be adjusted according to the use of the appliance.  As solar panels only produce Direct current the solar inverter is used to convert the DC to AC

An inverter produces square waves or a sine wave which can be used for running lights, televisions, lights, motors etc. However these inverters also produce harmonic distortion.

Solar technology is not new. Its history spans from the 7th Century B.C. to today. We started out concentrating the sun’s heat with glass and mirrors to light fires. Today, we have everything from solar-powered buildings to solar-powered vehicles. Here you can learn more about the milestones in the historical development of solar technology, century by century, and year by year. You can also glimpse the future. From the 3rd Century BC when Archimedes fought off Roman ships by concentrating the suns rays at them with brass shields (they burst into flame), through work by some of the best known figures in the history of science, harnessing the power of the sun has long been a goal of human innovation. Let’s look at some of the highlights:

In 1767Swiss physicist, alpine explorer, and aristocrat Horace de Saussure is credited with inventing the first working solar oven, amongst other discoveries.

Also in 1839 Edmond Bequerel, born in Paris in 1820, discovered that when two electrodes were placed in an electrolyte (electricity-conducting solution), a voltage developed when light fell upon the electrolyte. The basic principles of solar power had been uncovered.

Many people using solar power these days which prove that its necessity has been increased in the current years. A Solar inverter is similar to a normal electric inverter but uses the energy of the Sun, that is, Solar energy. A solar inverter helps in converting the direct current into alternate current with the help of solar power. Direct power is that power which runs in one direction inside the circuit and helps in supplying current when there is no electricity. Direct currents are used for small appliance like mobile e phones, MP3 players, IPod etc. where there is power stored in the form of battery. In case of alternative current it is the power that runs back and forth inside the circuit. The alternate power is generally used for house hold appliances. A solar inverter helps devices that run on DC power to run in AC power so that the user makes use of the AC power. If you are thinking why to use solar inverter instead of the normal electric one then it is because the solar one makes use of the solar energy which is available in abundant from the Sun and is clean and pollution free. Solar inverters are also called as photovoltaic solar inverters. These devices can help you save lot of money.  The small-scale grid  one have just two components i.e. the panels and inverter while  the off grid systems are complicated and consists of batteries which allows users to use appliances during the night when there is no Sunlight available.  The solar panel and the batteries that are placed on rooftops attract Sun rays and then convert the Sunlight into electricity. The batteries too grab the extra electricity so that it can then be used to run appliances at night.

1.1     Statement of the Study

The purpose of this work is to design and implement a 4kva solar power inverter system that transforms direct current (DC) generated by a PV system into alternating current (AC), which can be sent into AC appliances. These inverters can be used either in concert with battery systems or to directly power certain devices. They also tend to have a few identifying features that are specifically intended to be used with Photo Voltaic arrays, such as maximum power point tracking (MPPT).

1.2     Aims and Objective of the Study

The main objective of this project is to design and implement a solar power generating device that can collect an input dc voltage from the solar panel and convert it to 240v output which can be use to power ac appliances which is rated 4kva.

1.3     Significance of the Study

Solar inverter is useful in making appliances work at residential and industrial levels, such as:

A Solar Inverter is better optimized for solar power than the regular one. For example, it will prioritize power supply from the solar panels. This means that when the energy from the Sun is adequate like during afternoons, the inverter will draw power entirely from the solar panels to power your home or office even if public power supply is available. This can lead to huge savings on power bills.

Similarly, a Solar hybrid inverter will prioritize charging from solar panels, enabling your batteries to charge via the PV panels even when public power supply is on, leading also to savings on your power bills.

Solar inverter has always helped in reducing global warming and green house effect.Also use of solar inverter helps in saving money that would have used for buying fuel for conventional generatorSome solar inverters will allow you prioritize charging to solar panels or power grid depending the battery level. Some solar inverters are even intelligent enough just to take just as much deficit current from the grid as is required.

A solar inverter helps in converting the Direct current in batteries into alternative current. This helps people who use limited amount of electricity.

There is this synchronous solar inverter that helps small homeowners and power companies as they are large in size.

Then there is this multifunction solar inverter which is the best among all and works efficiently. It converts the DC power to AC very carefully which is perfect for commercial establishments.Solar inverters are the best way and they are better than the normal electric ones. Also their maintenance does not cost much money.

Solar Inverters can work when there is no Sunlight but provided their battery is charged fully with the help of Sunlight.

1.4     Scope of the Study

          The main function of solar inverter is to convert battery's Direct Current (DC) into pure sine wave Alternative Current (AC) to feed home compliances.

Solar power inverter system is consisted of solar panels, charger controllers, inverters and rechargeable batteries, while solar DC power system is not included inverters. The inverter is a power conversion device, which can be divided into self-excited oscillation inverter and external excited oscillation inverter.

1.5     Limitation of the Study

This device is rated 4kva that means any load more than 4kva should for no reason applied to this device.

The intensity of the Sun varies throughout the day. This creates an over-charging problem if the panels are connected to the battery directly, and It should also be able to tell you when you connect the panels wrongly (i.e. positive to negative, etc) and also provide protection against short-circuit. For this reason a charge controller must be used to offer protection from high voltage and current from the panels.

The inverter frequency is rated at 50hzIron casing and good heat sink is been used for heat absorption.

1.6     Definition of Terms

  • INVERTER: This is an electronic device that convert direct current (DC) to alternating current (AC).
  • SOLAR PANEL: Solar panel also known as Photovoltaic or PV are designed to absorb sunlight as a source of energy to generate electricity.
  • BATTERY: A battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlight, mobile phones, and electric cars.
  • MPPT (maximum power point tracking): Is a technique used commonly with wind turbines and photovoltaic solar systems to maximize power extraction under all conditions.
  • PWM (pulse width modulation): Is a method of reducing the average power delivered by an electrical signals, by effectively chopping it up into discrete parts.
  • SOLAR CELL: A solar cell is a device that converts light into electricity via the ‘photovoltaic effect’.