Construction Of 1.5KVA Power Inverter With 12V/100Ah Battery

1.0                                        INTRODUCTION

1.1                                      BACKGROUND OF THE PROJECT

A power inverter converts DC power (also known as direct current), to standard AC power (alternating current). Inverters are used to operate electrical equipment from the power produced by a car or boat battery or renewable energy sources, like solar panels or wind turbines. DC power is what batteries store, while AC power is what most electrical appliances need to run so an inverter is necessary to convert the power into a usable form (Owen et al., 2016). For example, when a cell phone is plugged into a car cigarette lighter to recharge, it supplies DC power; this must be converted to the required AC power by a power inverter to charge the phone.

In modified sine wave, The waveform in commercially available modified-sine-wave inverters is a square wave with a pause before the polarity transition, which only needs to cycle through a three-position switch that outputs forward, off, and reverse output at the pre-determined frequency(Owen et al., 2016). The peak voltage to RMS voltage does not maintain the same relationship as for a sine wave. The DC bus voltage may be actively regulated or the “on” and “off” times can be modified to maintain the same RMS value output up to the DC bus voltage to compensate for DC bus voltage variation(Owen et al., 2016).

The ratio of on to off time can be adjusted to vary the RMS voltage while maintaining a constant frequency with a technique called PWM. Harmonic spectrum in the output depends on the width of the pulses and the modulation frequency. When operating induction motors, voltage harmonics is not of great concern, however harmonic distortion in the current waveform introduces additional heating, and can produce pulsating torques (Grafham et al., 2012).

1.2                                               PROBLEM STATEMENT

If there is one factor that has perpetually maintained the status of Nigeria as a less developed country, it is its electricity sector. Till date, many households and industrial businesses cannot be guaranteed of 24 hours supply of electricity from the National grid. At this stage of Nigeria’s social and economic development, the country cannot deliver sufficient energy to the citizens despite huge financial resources that have been expended in the sector.

Rather, Nigerians have continued to rely on electricity generators for their power supply, fuel marketers are taking significant portion of households’ institutions of learning and businesses’ incomes to supply power, noise pollution from regular humming generators have become integral part of living for many Nigerians with imaginable consequences on their health. Because of these problems, there is a need to design and construct an inverter to complement or augment the electricity supply from the National grid, reduce cost of energy consumed and eliminate noise/environmental pollution that is associated with running of generator.

1.3                          OBJECTIVE OF THE PROJECT

The main aim of this project is to build a power inverter which can be powered from the source of 12V/100Ah battery to produce an output of 230vac. The objectives of the work are:

1. To build system prototype

iii.           To back-up the erratic power supply by PHCN.

1. To ensure the protection of the back-up source consumer equipment and supply.
2. To be able to connect 12v/100Ah battery to the inverter.

1.4                                           PURPOSE OF THE PROJECT

The purpose of this work is to build an electronic power generating device that is independent on the mains supply that changes direct current (DC) to alternating current (AC) which can go a long way ensuring uninterruptible power supply.

1.5                                       SIGNIFICANCE OF THE PROJECT

The inverter battery is the second most significant (and second most expensive) component of a system. It’s important because it converts the raw Direct Current (DC) power that is produced by battery into Alternating Current (AC) power that comes out of the wall sockets outlet. Inverters also have technology that maximizes the power output of that DC energy.

Secondly, the whole energy conversion process is environmentally friendly. It produces no noise, harmful emissions or polluting gases. The burning of natural resources for energy can create smoke, cause acid rain and pollute water and air. Carbon dioxide, CO2, a leading greenhouse gas, is also produced in the case of burning fuels. inverter uses only the power of the battery as its fuel. It creates no harmful by-product and contributes actively to the reduction of global warming.

1.6                                              SCOPE OF THE PROJECT

The scope of this work covers building a power conversion device. It converts fixed direct current (DC) voltage to frequency sinusoidal alternating current (AC) voltage output.  The input voltage (12vdc), output voltage (230vac) and frequency (50hz), 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 typical power inverter device or circuit requires a relatively stable DC power source capable of supplying enough current for the intended power demands of the system. The input voltage depends on the design and purpose of the inverter.

The waveform of this work is modified sine wave. The modified sine wave output of such an inverter is the sum of two square waves one of which is phase shifted 90 degrees relative to the other. The result is three level waveform with equal intervals of zero volts; peak positive volts; zero volts; peak negative volts and then zero volts(Grafham et al., 2012). This sequence is repeated. The resultant wave very roughly resembles the shape of a sine wave.

1.7                                       ADVANTAGES OF THE PROJECT

Power inverters are used to power and control the speed, torque, acceleration, deceleration, and direction of the motor. The use of inverter has become prevalent in wide range of industrial applications; from motion control applications to ventilation systems, waste water processing facilities to machining areas, and many others. Though power inverters offer lower operating costs and higher efficiency, they are not without their problems.

1.8                                         LIMITATION OF THE PROJECT

• Expensive when compared to traditional generators
• There are no large capacity inverter in the markets
• The inverter can power a few appliances for a short period
• The input is limited to 12VDC, output to 230VAC, the frequency to 50Hz and the battery current per hour to 100Ah
• The power rating of the work is 1.5kva

1.9 METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design and calculation for the device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out.

• Finally, the whole device was cased and final test was carried out.

1.10 PROJECT ORGANIZATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.