FYP1-1 Progress Evaluations

During Week 1, I have attended the Final Year Project (FYP) briefing as follows:

Date: 18/10/2022
Venue: Dewan Kuliah 4, P19
Time: 2.00 pm – 4.30 pm

The title of my FYP is "A design study on double-conversion technique UPS system".

The UPS system designed will have an additional component that could help to increase the power efficiency to the system compared to the conventional type of a UPS system.

To implement my design study, I have decided to use MATLAB Simulink R2022b as it has all components needed to design the UPS system with some modifications must be done. The UPS system design will be done part by part where the main components of the system must be designed before it will be combined together to make a complete UPS system. The main components of a UPS system is rectifier, inverter, battery set, and static bypass switch. There is another component to be added which is a buck converter with a PID controller that will be connected after the rectifier and before the battery set.

The figure below represent a complete system will all components needed in general:

What is an Uninterruptible Power Supply (UPS) system and its function?

• It is imperative to understand that an uninterruptible power supply, or UPS for short, is a device that connects in between the utility power supply and a load.
• Its main purpose is to provide an emergency power supply when the utility power supply fails.
• The design of the system is based on power electronic concepts and can be implemented for single-phase (240V) or three-phase (415V) applications, depending on the requirements of each application.
• It is intended that the UPS system's main alternating current (AC) supply will be used to charge the battery bank, which will serve as a backup power supply if the AC input power supply fails at any time during use.
• Additionally, the system protects loads from power outages, overvoltages, undervoltages, and harmonic disturbances.
• It is a system that is widely used in industries such as health facilities, data server systems, emergency equipment, industrial management, etc.
• Consequently, it is necessary that a UPS system is capable of providing sufficient emergency electrical power while protecting loads at the same time.
• It is necessary for an ideal UPS system to regulate pure sinewave voltage with very low total harmonic distortion (THD), zero switching time between different operation modes, high efficiency, high reliability, low electromagnetic interference (EMI), low acoustic noise, effective electric isolation, low maintenance, and low cost, weight, and size.

Project Background

In 2020, it is reported that the power demand for Peninsular Malaysia has increased 2.3% annually since 2015 to 2020 and it is expected to be growing by 0.9% per annum for the year 2021 to 2030 and 1.7% per annum for the year 2030 to 2039. The increment of power demand is to support the consumers need as well as the expansion of information-related businesses. This can boost the possibilities for the electricity power supply to be interrupted which can cause unfunctional equipment that needed continuous power supply. One of the critical loads that requires ongoing power supply is the modern medical systems in the health facility that is used to support the patients.

An uninterruptible power supply (UPS) is a system that connects between a utility power supply and the load with its main function to provide emergency power supply to critical loads when the supply from the power utility fails. It is a system with a design based on the power electronic concepts that be used for single-phase (240V) or three-phase (415V) depending on its application. The main alternating current (AC) supply of the UPS system is used to charge the battery bank for it to use as a supply when the AC input power supply fails. 

There are numerous types of UPS configuration that used by the manufacturers to design the UPS system with the consideration of its advantages and disadvantages. A single-phase on-line (double conversion) UPS system is one of the effective UPS configurations where the load is always supplied by the inverter regardless of the condition of the AC input power supply. It is an ideal UPS configuration system for the application where electrical isolation is necessary.

The benefits of a UPS system to protect the critical load is due to the system has low total harmonic distortion (THD), zero transfer time when the power utility fails, and its high input power factor. However, it has smaller efficiency due to its two power conversion stages.

Therefore, UPS system is a reliable backup system that helps to provide short term enough availability of electrical power to the critical loads when utility power supply fails.

Problem Statement

The fundamental role of a UPS system is to provide enough emergency backup power supply with a time constraint when the utility power supply fails. One of the applications of a UPS system used is in a health facility where all the modern medical system requires continuous electrical power supply to be functioned. It is essential to ensure the lifesaving equipment operates and protect important electronic data of the patients. A momentary interruption in the supply of electricity may cause harm to patients undergoing surgery or undergoing diagnostic tests.

The other functions of the UPS system are to correct common utility power problems such as utility power failure, undervoltage, overvoltage, frequency instability, and harmonic distortion. The problems stated may or may not cause the unexpected disruption to power supply that could cause a system blackout. In order to overcome these problems, a double-conversion UPS system is the best option that can provide 24-hour power conditioning to the load and produced sufficient on-going power supply to the critical load as a backup.

Project Objectives

The objectives of this project are as below:

1. To study the concept of a double-conversion UPS system.
2. To simulate double-conversion UPS system using MATLAB Simulink.
3. To compare the efficiency of the simulated UPS system and the conventional UPS system.