1. Solar Converter

1.1 Introduction There was a time when fossil fuels were the only source of energy and the world heavily relied on the instruments that were being operated using fuels like petroleum, natural gas and similar other resources. With the increase in industrial needs, the fossil resources faced an immense decrease which forced the scientific world to give serious attention to explore alternative sources of energy. This was the time when the concept of renewable energy was introduced and research was started to obtain energy from renewable energy resources like sun, wind and tidal waves.

Solar energy is a form of renewable energy obtained from the light of sun. Extraction of energy from sunlight became possible only when devices made of silicon such as diodes, transistors and integrated circuits were introduced and the field of power electronics were given importance. The main issue that engineers were encountering regarding the operation of these devices were their inefficiency and harmonic content development. Hence, the scientists were again forced to device much efficient techniques and devices so that the efficiency can be increased and harmonic contents can be reduced.

This project basically aims at the determination of efficiency of a solar converter at standard test

conditions of irradiance level of 1000 W/m2 and panel temperature of 25 oC. The efficiency is determined using the DC power at the input end of converter and AC power obtained at the output end of the converter connected with the grid.

1.2 Construction The solar converter under consideration, is basically constructed using the following modules.

1. H-bridge 2. Gate drives 3. Filter 4. Control 5. Solar panels 6. Sensors

H-bridge H-bridge is composed of four switches arranged in a pattern that visually resembles the English letter ‘H’. The switches are usually replaced by transistors. In this project, MOSFETs are used as switches. H-bridge is used to convert DC voltage into a pulsating AC voltage which can then, be filtered to get pure or near to pure sine wave.

Gate Drives Gate drives are electronic circuitry used to drive the Gate of MOSFETs in H-bridge and hence, are called Gate drives. They provide the required voltage level and current to the Gate of MOSFETs for their proper switching.

Filter Filters are generally used to pass one band of frequency components and stop another band of frequency components in a signal. In the project, an inductor is used to filter out higher harmonics of

the output generated using H-bridge and pass only the power frequency component of the output, so that we get pure sine wave at the output.

Control The control is developed using controllers and is used to compare the reference output voltage and measured voltage and the generate control signals for the Gate of MOSFETs accordingly.

Solar Panels Solar Panels are the devices that convert the solar energy of light into electrical energy.

Sensors Sensors are the devices that sense a specific physical quantity and convert them into electrical signals. In this project, voltage and current sensors are used to measure voltage and current at various points for efficiency determination and operation of control module.