CHAPTER ONE

INTRODUCTION

1.1       Preamble

A power inverter, or inverter, is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). (The Authoritative, 2000). The input voltage, output voltage and frequency, and overall power handling depend on the design of the specific device or circuitry. The inverter does not produce any power; the power is provided by the DC source. A power inverter can be entirely electronic or may be a combination of mechanical effects (such as a rotary apparatus) and electronic circuitry. Static inverters do not use moving parts in the conversion process. (Power Inverter, 2014)

A solar inverter, or PV inverter, converts the variable 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 inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking and anti-islanding protection. (Solar Inverter, 2014)

This project work involves the design and construction a 1kVA mobile solar power inverter system.

1.2       Statement of the problem

Uninterruptible power supply units are common electrical items found in most private and industrial buildings in Nigeria as a result of the never-stable and not-always-available power supply situation in the country. However, these units have not provided the much desired reliable, efficient and effective power supply delivery to their owners because these not-very-intelligent units do not, most of the time, get energy to recharge their built-in batteries.

Hence, there is a need to design and implement a power inverter system that gets energy to recharge its built-in battery from solar energy that is relative cheap and available.

  1.3      Aim and Objectives

Aim

The aim of this project work is to design and construct a 1kVA mobile solar power inverter system.

Objectives

The objectives of carrying out this project work are to:

1. harness the potentials of solar energy for power (energy) generation for domestic usage.
2. design a 1kVA mobile solar power inverter system that can be moved around and provides power where and when needed.

1.4       Significance of Study

Human needs are numerous and the resources to satisfy these needs are limited and in most cases scarce. Hence, there is a need to maximize these limited resources and to minimize waste of these resources to the barest minimum. Energy (power) is one of those limited resources that man needs to satisfy his numerous needs. The 1kVA mobile solar power inverter system seeks to provide a means to adequately, harness the potentials of solar energy for power (energy) generation for domestic usage.

1.5       Scope of Study

The mobile solar power inverter system would be built around a 1kVA power inverter whose output is controlled by an embedded microcontroller in relation to the battery voltage level. At the heart of this design, the microcontroller, PIC16F876A, with associated circuitry would be used for the control of the harvesting of solar energy (MPPT) and charging of the battery. The design of the mobile solar power inverter system would be implemented to have one sole source of energy, solar energy, available to charge the built-in battery of the inverter system.

1.6       Methodology

To achieve the objective of this project, the following are the methods and procedures that would be adopted:

1. Review previous works done on power inverters and solar system applications in power generation and management.
2. Design a 1kVA mobile solar power inverter system that harnesses the potentials of solar energy for power generation.
3. Design an on-board microcontroller unit for handling maximum power point tracking (MPPT) for the solar charging section of the design, and the control of the whole mobile solar power inverter system.
4. Construct a 1kVA mobile solar power inverter system that would feature the above- listed designs.
5. Test the constructed electronic system to ensure that the above listed objectives are duly met and that engineering standards for appliances design are not compromised.
6. Document the whole process and procedure for this design work, keeping good records of the voltages at test points, readings obtained during the testing and calibration stages.