Theses & Dissertations

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https://hdl.handle.net/20.500.14170/206

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Now showing 1 - 5 of 256
  • Publication
    Non-invasive jaundice detection system using colour card technique
    (Universiti Malaysia Perlis (UniMAP), 2018)
    Asyraf Hakimi Abu Bakar
    Jaundice is described as yellow discoloration of the skin and other tissues of a newborn infant and it is conjunctiva due to the increase of bilirubin up to 5 mg/dl or 85 𝛍mol /l. In Malaysia, a survey made by Ministry of Health Malaysia proves that about 75% ofnewborns had jaundiced in the first week of life. Current jaundice assessment method have their own drawbacks. The traditional method (Kramer's Rule) is not convenientsince there are limits to the accuracy of visual estimation and may lead to human error. Thus, a blood test taken from baby's heel remains to be necessary but it leads to traumatization for the baby as well as their parents. Moreover, the available jaundice meter in the market is expensive. This jaundice detection using color card demonstrated in this research shows a high potential to give positive impact on the medical and healthcare fields. This research work proposed an automated jaundice (hyperbilirubinemia) detection system and the suggested treatment based on the color card technique. This research does not involve any subject or infant. It acquires data by capturing different type of color shades using spectral reflectance method. It represent random bilirubin color in patient's body, the human skin color represented by Fitzpatrick shades, and bilirubin concentration color card using silicon photodiode sensor. The data gained are transferred wirelessly to a gateway and subsequently to a computer to perform computation and analysis. The input data were validated using Anderson-Darling normality and compared with the reference card using linear regression and Pearson's correlation coefficient analysis to predict the particular bilirubin value and treatment needed for each input sample tested. Percentage error analysis is used to verify and validate the experimental device. The final outputs are shown in a graphical user interface on medical staffs PC and can be viewed only by the authorized personnel. Based on the results of linear relationship and correlation between input sample and reference data, it shows high percentage result (R²) between 86.4% to 99.4%, and correlation value (r) 0.918 to 0.997. Result of highest percentage error (% error) shows value of 9.90% and verify that this device is reliable. Thus, it can be concluded that the color card technique is reliable and can be used to detect and predict the jaundice level for any type of skin color.
  • Publication
    Fifteen-level multilevel inverter with reduced active power semiconductor switches and real-time switching-angle calculation technique (Restricted)
    (Universiti Malaysia Perlis (UniMAP), 2018)
    Soo Jian Aun
    Cascaded H-bridge multilevel inverter (CHBMI) is able to generate a staircase alternating current (AC) output voltage waveform with lower switching losses compared to two-level high switching frequency pulse-width modulation (PWM) inverter. However, the large number of active power semiconductor switches required in a conventional CHBMI may give rise to reliability issues. In addition, the switching angles applied in a conventional CHBMI are usually calculated using a set of non-linear transcendental equations, which is difficult to be solved and implemented in real-time. This thesis proposes a 15-level CHBMI with reduced active power semiconductor switches and real-time switchingangle calculation technique for wide modulation index operation. While the conventional CHBMI requires 28 switches to produce a 15-level output voltage waveform, the proposed CHBMI which employs a set of binary asymmetric H-bridges (HB) requires only 12 switches to produce the same output voltage waveform. A geometry based switching-angle calculation technique, which can be implemented in real-time, has been applied to the proposed CHBMI. The technique is able to calculate the switching angles for modulation index ranging from 0 to 1 and the lowest total harmonic distortion (THD) obtained is 5.32% at modulation index of 0.81. The performance of the proposed CHBMI has been evaluated via MATLAB/SIMULINK-SimCoupler-PSIM simulation and verified via 15-level CHBMI prototype. Both simulation and experimental results are in good agreement. Furthermore, experimental evaluation of the CHBMI prototype also shows that the system has a good real-time response to changing input modulation index.
  • Publication
    Simulation of micro hydropower system based on Pelarit river potential for Gua Kelam electricity supply
    (Universiti Malaysia Perlis (UniMAP), 2016)
    Rosnita Md Aspan
    Sufficient and uninterrupted electricity supply is one of the main factors to develop the country. Today, electricity can be generated using a variety of sources, whether from non-renewable sources as well as renewable resources. To generate electrical power, Malaysia can't rely entirely on non-renewable resources such as petroleum and coal as these are finite resources which are experiencing depletion around the world. Electricity generated from renewable sources such as water, particularly from micro hydropower systems is considered the cheapest and most environmentally friendly source of electrical energy. In the reconnaissance study conducted, it was found that the streams of flowing water to Pelarit River have the potential to yield about 34.29 kW of electricity power, based on the head height of 27 m and flow rate 0.216 m3/s. In this research, a simulated model for an ordinary micro hydropower facility has been developed. It was done through the settings that linked various electromechanical equipment consisting of a hydraulic turbine and governor, and a synchronous generator, using Matlab/Simulink. The modeling was executed to design a micro hydropower system as an alternative source of supply of electricity to Gua Kelam, Pedis, based on Pelarit River potential. The proposed model was tested by placing a three-phase fault to earth for the purpose of testing the reliability of the system. With the selection of an appropriate control system, the proposed model was found to be very suitable for the development of micro hydropower system at a potential site such as Gua Kelam.
  • Publication
    Analysis and development of low THD single phase 11-level multilevel inverter
    (Universiti Malaysia Perlis (UniMAP), 2016)
    Nurhayati Silahhuddin
    Solar energy is among the renewable energies that are gaining popularity for electrical power generation. Solar energy is converted into direct electricity (DC) using photovoltaic (PV) panels. Since most of the standard electrical appliances operate in alternating current (AC) mode, the DC electricity must be converted into AC form. An inverter is used to perform such function. Conventional PWM-controlled inverter is switched at tens of kilo-hertz range, and this will lead to high switching losses and reduced efficiency in the system. In contrast, a multilevel inverter can be switched at a much lower frequency and will produce lower switching losses and hence, higher efficiency. Among the multilevel inverter topologies, cascaded H-bridge multilevel inverter is gaining popularity for high power PV applications because the modular structure enables higher voltage operations using standard low-voltage semiconductors This project focuses on the modeling, simulation and hardware prototyping of a elevenlevel cascaded H-bridge multilevel inverter. The simulation model of a eleven-level cascaded H-bridge multilevel inverter is modeled using PSIM software. However, the switching angles of the eleven-level cascaded H-bridge multilevel inverter must be properly selected so that a staircase AC output voltage waveform which is to a near sinusoidal waveform can be obtained. Therefore, four switching angle arrangement techniques are evaluated in the simulation. Simulation result show that one of the switching angle arrangement techniques is able to produce an output voltage waveform with harmonic contents as low as 7.56%. To validate the simulation result, a hardware prototype of the eleven-level cascaded H-bridge multilevel inverter was constructed and tested. The experimental result shows that the harmonic contents of the inverter is 7.56%, which corroborates with the simulation results.
  • Publication
    Improvisation on voltage sag occurrences at UniMAP Pauh through implementation of D-STATCOM
    (Universiti Malaysia Perlis (UniMAP), 2016)
    Hulaimy Ahmad Termizi
    In power system, one of the power quality problems is the voltage sag that mostly occurs in the engineering. The voltage sag is the reduction of the rms voltage at the certain period or certain cycle in a short period oftime. Voltage sag refer to decreasing ofrms voltage in between 0.1 pu to 0.9 pu in a period of0.5 cycle to 1 minute. Voltage sag commonly caused by fault within the system however it is also caused by the starting of large motor or switching of a heavy load. One of the solution that can be applied to mitigate or improvise the voltage sags is by using the Distribution Static Compensator (DST A TCOM). It is a power controller that gives a flexible voltage controlled with a fast response characteristic to provide a power system quality improvement. When the system voltage is lower than inverter voltage, D-STATCOM will inject reactive power to the system and when the system voltage is higher than inverter voltage, the D-STATCOM wiJI absorb the reactive voltage. The circuit is design in the Power System Computer Aided Design (PSCAD) software and all parameter will design base on the power system network characteristic. There are two type of Voltage Source Converter (VSC) that is voltage source inverter (VSI) and voltage source rectifier (VSR). These VSC used semiconductor switches as the switching devices and the pulses will trigger those switches. By referring to advantage and disadvantages, gate turn off thyristor (GTO) will be used as the switching device. DC capacitor play an important role in storing the energy that used to mitigate voltage sags. It is used to supply the reactive power through DST A TCOM when voltage sags occurs. In this simulation, the three-phase induction motor has been used as the load for the AC system. The data of the motor was taken from the real motor in cooling tower near the PPKSE School at UniMAP. Without using the D-ST A TCOM, the sag duration was about 0.5s for both sag occurrences and the voltage sag were slowly disappear when the induction motor reach it rated speed. The voltage sag that occurs in the simulation system has a reduction of voltage for 40% (the highest) and 28% (the lowest). From the IEEE standard, it prove that the decreasing of voltage occurrences is in between 10% - 90% in a period of 0.5 cycle to I minute. By implementing D-ST ATCOM, it shows that the voltage sag has been 99% completely being mitigated. D-STATCOM gives a huge contribution for optimizing power quality issue in unbalances distribution network.