Nurhafiza Azizan
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Preferred name
Nurhafiza Azizan
Official Name
Nurhafiza, Azizan
Alternative Name
Azizan, N.
Azizan, Nurhafiza
Azizan, N. S.
Main Affiliation
Scopus Author ID
57189593226
Researcher ID
GQR-9188-2022

Research Output

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Simulation of single phase fuel cell powered transformerless multilevel inverter using H-Bridge cascade topology

2014 , Nurhafiza Azizan

In this thesis, a multilevel inverter is constructed using H-Bridge Cascaded circuit to obtain output voltage for three, five, seven and nine level. It is operated without transformer to obtain a nominal voltage of240V. It needs DC voltage from fuel cell that will convert to the AC nominal voltage. This research was discussed about the output voltage waveform of the H-Bridge Cascaded multilevel inverter approaches the pure sine wave simulation. The simulation uses MA TLAB software to get the output waveform from fuel cell and the H-Bridge cascaded multilevel inverter topology. The topology is to obtain optimal values of voltage angle. The optimum voltage angle results will reduce the lowest (THD) total harmonic distortion and to be implemented in this research. The simulation results will be compared based on the THD results. As the level increases from three to nine levels, the THD shows significant improvement of reduces from 36.13% to 10.14%. Therefore, among three to nine levels of H-Bridge Cascaded multilevel inverter, only the nine levels was chosen for further analysis. The analysis was using SHEPWM switching technique. Comparison between the results analysis of nine levels for modulation indexes 0.75 to 1, has obtained that 10.14% is the best THD results. The comparison results are approximately equal between fuel cell and reference of previous researcher based on the simulation. Therefore, fuel cell also can be used as DC voltage source transformerless multilevel inverter.

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Water-Based Energy Production Using PI Controller

2022-01-01 , Ali N.I.H.M. , Nur Irwany Ahmad , Muhammad Zaid Aihsan , Diyya Hidayah Abdul Rahman , Mohamad Shukor Abdul Rahim , Nurhafiza Azizan , Mokhtarddin H. , Jalaludin B.M. , Zaidi A.A.H. , Saleh A.

Malaysia is now heading for usage of renewable energy in daily use. Nowadays, solar technologies already provide energy for heat, light, hot water, and electricity for businesses and industries. Besides, Malaysia blessed with abundance of water sources and receive high rain volume per year which can be used to generate power. In Malaysia, the ambient temperature is approximately 27 ℃ but it depends on the different location. Different location has different temperature regarding to its different environment. Even though the peak sun hour in Malaysia is 5 to 7 hours per day, the ambient temperature from 32.2 to 35 ℃, can be consider as high temperature. The Standard Test Condition (STC) of solar photovoltaic (PV) is 25 ℃. Therefore, if temperature higher than 25 ℃ is used, it will drop the efficiency of solar PV. To overcome this problem, a new concept of energy production using hybrid system of piezoelectric and peltier generator prototype is developed. In this research, a buck boost converter using Proportional Integrated (PI) controller is designed to boost the output and maintain it in the range of output needed from the harvesting system, which is 12 V. MATLAB software is used to design and simulate the circuit. Hence, the performance of water-based prototype has been evaluated and analyzed based on voltage, current and the power produced by the prototype.

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Dynamic Partial Discharge Characteristic for Onsite Measurement Based on Zero Crossing in Power Cable

2022-01-01 , Ahmad Zaidi Abdullah , Bohari Z.H. , Nurhafiza Azizan , Muzamir Isa

This paper analyzed the dynamic Partial discharge (PD) characteristic for onsite measurement based on zero crossing in high voltage power cable. According to IEC60270, high voltage measurement characteristic is required to identify correct PD signal. There is currently limited research operating on the trait, especially zero crossing, and because of this, comprehensive PD detection characteristics need to be further established in certain severe conditions. This occurrence has an erratic and sporadic characteristic that is challenging to identify. This paper explored the time of zero crossing for onsite measured PD signal for power cable through MATLAB simulation. This task is crucial to choose the range of zero crossing time based on the highest peak of detected PD signal. Based on the detailed analysis, it is substantially identified that there is an specific time only for PD signal with the highest amplitude, and based on detected times, a range of zero crossing characteristic was described for PD signal. It provided a useful analysis result for the guideline during onsite PD measurement for power cable.

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Modelling and simulation of online partial discharge measurement for medium voltage power cable

2020-04-01 , Ahmad Zaidi Abdullah , Muzamir Isa , Mohamad Nur Khairul Hafizi Rohani , Haziah Abdul Hamid , Bin Amlus M.H. , Nurhafiza Azizan

This paper presents the modelling of the online partial discharge (PD) measurement of the medium voltage (MV) power cable. Recently, PD monitoring trends are rapidly increasing due to high demand on reliable systems. Degradation are mainly due to the presence of PD in the high voltage power equipment used. PD measurement is therefore a highly recommended task to early detection of the degradation insulation for high voltage (HV) equipment in order to avoid breakdowns. Real network modelling is necessary to improvise system design in order to find the efficiency in a real power system network. In this paper, modelling focuses on a real distribution network by applying Rogowski coil (RC) as a detection sensor to trigger PD activity. The simulation is performed to determine the functionality and reliability of the system with the RC application in the network. The analysis is performed in the ATP-EMTP and MATLAB Simulink software environments. In addition, this paper contributed to justify the approach of a simplified PD sensor and measurement system. This PD measurement system provides a complete solution in the context of condition-oriented monitoring for the ability to apply the RC to trigger PD activity in the power distribution network.

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Investigation of solar energy production by Photovoltaic (PV) system using rooftop coating as passive cooling technique at Bukit Tinggi, Malaysia

2025-04 , Ahmad Zaidi Abdullah , Nurhafiza Azizan , Nurul Atiqah Kadir , Nurul Nadirah Mohd Hussin

Solar power energy is known as one of the popular renewable energies that has been studied by many researchers all over the world. Photovoltaic (PV) panels are used to produce electricity directly from the sunlight. Cooling is a very important technique used in the PV system industry. This is because the heat generated by the PV system can reduce its performance, resulting in higher costs. The cooling technique consists of two types: active cooling technique and passive cooling technique. In this investigation, the passive cooling technique is selected. This is due to its advantages such as less maintenance, did not require large space and affordable. The nanocoating method is a widely used as passive cooling method for glass and PV panels. However, this investigation is carried out to investigate the rooftop coating integrated with PV panels system at Bukit Tinggi due to the limited previous research found worldwide. M168 coating is applied to the rooftop and the effects on the PV systems have been investigated. Two sets of On-Grid Connected PV systems were set up; where each system consists of two inverters were set up to analyze the output. The results then were recorded. According to the investigation results, the PV system with a coated rooftop generates a higher voltage of 249.80V and total power production difference of 16% compared to the PV system with an uncoated rooftop. Although the temperature for coated rooftop PV system quite higher than the uncoated rooftop PV system at the beginning, then the temperature constantly lower than the uncoated rooftop PV system. This study can be used as a guideline for PV system passive cooling methods at Bukit Tinggi.

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Performance analysis of different type PV Module for 3kW residential roof top PV System using PVSyst Simulation tool

2022-01-01 , Ahmad Zaidi Abdullah , Mohammad Harith Amlus , Nurhafiza Azizan , Sali I.M. , Rahim M.H.

The purpose of this article is to discuss a performance comparison of solar panel between mono crystalline, poly crystalline and HIT photovoltaic for roof top solar photovoltaic (PV) system. Residential PV power generation is a growing fast nowadays due to technology transfer success to everyone while also serving as a renewable energy source. Correct selection of PV modules possible to get a fast return of investment while wrong selection is vice versa. Three type of PV panel was applying in 3.12kW rooftop PV design in Selangor, Malaysia residential this work for comparison analysis. To make a fair comparison, the PV module analyse with same location, weather, orientation and losses. Simulation was performed fully under PVSyst software and looking at performance ratio system, a yearly balanced, effective output energy, daily output generation, system output generation, and yearly system losses. In this article the performance of three different types of PV panels is demonstrated. The HIT PV module shows the highest yearly performance ratio up to 81 % compare to mono and poly type. The normalized production with standardized variable to evaluate the PV output including collection losses, device losses and energy generated show the HIT type produces lowest losses while highest output. The performance of HIT PV module was good compared to PV module mono and poly type; this is due to the lower losses and high output produce significantly. The PV system's payback period can be shortened, and the PV system can perform better, if the PV panels are more efficient.

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Partial Discharge Rise Time Characteristic based on Experimental Measurement in Power Cable

2023-01-01 , Hashim M.H. , Ahmad Zaidi Abdullah , Syahrun Nizam Md Arshad @ Hashim , Muzamir Isa , Jamal A. , Nurhafiza Azizan

This study presents a comprehensive investigation into the rise time characteristics of partial discharges (PD) in cable insulation through experimental measurements. Partial discharges are a critical phenomenon in high-voltage systems, serving as an early indicator of insulation degradation. Understanding the rise time of partial discharges is essential for assessing the severity of insulation defects and ensuring the reliability of power cable systems. The experimental setup involved controlled conditions to induce partial discharges in cable samples, allowing for precise measurement and analysis of the rise time. The study explores the correlation between rise time and different factors such as cable design, insulation material, and defect type. Results indicate that the rise time of partial discharges exhibits distinct patterns based on these factors, providing valuable insights into the nature of insulation defects. The findings contribute to the development of effective diagnostic tools for condition monitoring in power cable systems, ultimately enhancing the reliability and safety of electrical infrastructure.

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First Principles Enhanced Electronic Band Structure of Back Contact in CdTe Solar Cells using DFT+U Method

2023-01-01 , Ahmad N.I. , Nurhafiza Azizan , Kar Y.B. , Doroody C. , Syahrun Nizam Md Arshad @ Hashim , Ahmad Zaidi Abdullah , Jamal A.

Cadmium telluride (CdTe) superstrate solar cells have captivated the industry with their remarkable cost-effectiveness. However, optimizing the composition and optoelectrical properties of optimal back surface field (BSF) which can act as a lattice matching interface between the back contact and absorber layer remains a key challenge due to the work function disparity of p-CdTe with metal contacts. In this study, the influence of the Hubbard U parameter on the calculated electronic properties of ZnTe as an optimal BSF compound is presented using the density functional theory (DFT) technique. The Hubbard U value progressively increased from 1 to 4.2 to analyze its influence on the band diagram and Total Density of States (TDOS) in a full comparison of DFT and DFT+U approaches. As the value of Hubbard U increased, the band gap energy exhibited a corresponding increase from 1.20 eV to 2.24 eV, respectively. In comparison, the DFT+U approach with a value of 4.2 exhibited superior accuracy in predicting the band gap of ZnTe, yielding a value of 2.24 eV that closely approximated experimental measurements. This finding reinforces the relevance of employing Hubbard U to achieve more accurate and reliable band gap values for any material doping.

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Development of savonius vertical windmill with charging system

2022-01-01 , Halim N.A.W.A. , Diyya Hidayah Abdul Rahman , Ahmad N.I. , Habibah H.M. , Norhanisa Kimpol , Nurhafiza Azizan , Ahmad Zaidi Abdullah , Nur Zawatil Zakaria

The goal of the project is to achieve an output voltage at range 1 V until 13 V. In recent years, the use of small- scale green energy technologies has grown exponentially. This further highlights the need for innovation in this area, especially for small-scale applications. Global warming results from carbon dioxide gas accumulation in the atmosphere and the depletion of the ozone layer and carbon dioxide emissions from fossil fuels. To get the clean energy sources are not only an alternative to a finite supply of fossil fuels but also a way of helping to mitigate the harm that have been caused. Researchers around the world are looking into cheaper, renewable, and more reliable sources of energy which is wind turbine to produce kinetic energy and transformed into electrical energy. Usually the size of wind turbine was larger and heavy. Therefore, this research aims to design the Savonius vertical windmill with a charging system that displays the desired output. This research used SolidWorks software to design the blade and generator part and using Arduino software to control the charger circuit. The outcomes investigation result from Savonius vertical windmill affordable to produce output voltage of 2.33 V.

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Evaluation on innovation approaches on performance from Malaysian perspective: A study on Malaysian Building energy saving

2018 , M. H. Amlus , Amlus Ibrahim , Ahmad Zaidi Abdullah , Nurhafiza Azizan , Ummi Naiemah Saraih

Lately Malaysia energy consumption versus generation rapidly shows increasing due to increasing of load. This phenomenon happened following to advanced country development. Lacking on design and without energy management approach the energy consumption and monthly electrical bill will steadily increased and support the increasing of world carbon emission. Therefore the aim of this work is to approach the simplest innovation task-energy audit , which is load-apportioning strategy. This approach using matching the usage of equipment with fully utilized space and reschedules the time of usage. A one week data was collected by logged power meter at main switchboard at selected building using Fluke Power Recorder. From the data collected, current usage of every load can be determine, then load will be arrange into a group with same portion and same time of usage. The result shows clearly the energy consumption for every single day and indicates the highest and lowest peak. From this work the apportioning strategy implemented by rearrange the load following type of room application. After the arrangement, new measurement was taken and a very good result was established. This work also can be further apply for a huge load that can be save a lot of money for owner especially government by energy saving.

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