Leow Wai Zhe
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Preferred name
Leow Wai Zhe
Official Name
Wai Zhe, Leow
Alternative Name
Leow, Wai Zhe
Leow, W. Z.
Zhe, Leow Wai
Zhe, L. W.
Main Affiliation
Scopus Author ID
56178375200
Researcher ID
DXJ-9302-2022

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MPPT charge controller using fuzzy logic for battery integrated with solar photovoltaic system

2025-05 , Kumuthawathe Ananda-Rao , Afifah Shuhada Rosmi , Steven Taniselass , Nor Hanisah Baharudin , Leow Wai Zhe

In comparison to other Renewable Energy (RE) resources, solar energy has become the most prominent and prospective source for generating electricity, substituting conventional sources. However, solar Photovoltaic (PV) energy production is dependent on solar irradiance and cell temperature. By implementing the Maximum Power Point Tracking (MPPT) algorithm, it is achievable to maximize the power from solar PV. In spite of this, there is still a slower convergence rate, a significant fluctuation around Maximum Power Point (MPP), and a drift issue caused by rapid irradiance variations in solar PV. In order to prevent oscillation and attain a steady state and continuous output of the PV module, a Fuzzy Logic (FL)-based MPPT has been designed in this work. With the buck converter as the DC-DC converter and the lead acid battery as the input, the Perturb & Observe (P&O) MPPT method is selected. The overall design will be developed using Matlab Simulink, and the efficiency of the FL-MPPT charge controller will be evaluated under constant and step irradiance. Additionally, the battery's State of Charge (SOC) will be monitored to prevent overcharging and discharge. In addition, the effectiveness of the controller will be evaluated with and without the MPPT method. On the basis of simulation results obtained from constant and step irradiance levels, the FL-MPPT charge controller with the P&O algorithm and the lead acid battery as the load was able to maintain maximum system efficiency while extending battery life. The FL-MPPT charge controller obtained about 96% efficiency for both irradiance profiles, whereas the system without the FL-MPPT algorithm only achieved 42% efficiency.

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Breast cancer status, grading system, etiology, and challenges in Asia: an updated review

2023 , Tan Xiao Jian , Cheor Wai Loon , Cheng Ee Meng , Khairul Shakir Ab Rahman , Wan Zuki Azman Wan Muhamad , Leow Wai Zhe

The number of breast cancer incidences reported worldwide has increased tremendously over the years. Scoping down to Asia, in 2020, the reported incidences of breast cancer are appalling, comprising 1,026,171 cases, occupying up to 45.4% of cases across the globe. Breast cancer is a non-communicable disease, that emerges in variegated forms, self-subsistent, and the etiology is observed to be multifactorial, dependent on the individual reproductive pattern, hormonal factors, diet, physical activity, lifestyle, and exposure to certain advent procedures. Given this complexity, breast cancer is expected to undergo a persistent increment in the number of incidences in near future, exacerbating the public health quality, regardless of race, ethnicity, geographical subgroups, and socioeconomic. In this review article, the authors examine breast cancer in multiple facets, comprising the updated statistics on breast cancer, typically in Asia; etiology of breast cancer; diagnosis of breast cancer; grading system; and challenges in breast cancer from the country’s income perspective. Realizing the ever-increasing demand for quality treatment, here, the article also contemplates common therapies in breast cancer, such as breast-conserving therapy, mastectomy, postmastectomy radiation therapy, neoadjuvant chemotherapy, axillary surgery, chemotherapy, adjuvant medical therapies, biological and targeted therapies, and endocrine therapy. This review article intended to provide a brief yet broad panoramic view of breast cancer, to readers, ranging from newcomers, existing researchers, and relevant stakeholders in the topic of interest.

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Assessment of wind power potential in the North region of Malaysia, Chuping Perlis

2023-01-01 , Thiraphorn Bun Leew , Leow Wai Zhe , Mohd Irwan Yusoff , Safwati Ibrahim , Tan Xiao Jian , Muhammad Irwanto Misrun , Kumuthawathe Ananda-Rao

The wind turbines is a main device that convert the kinetic energy from blades to electrical energy. Before installing wind turbines, the Weibull probability distribution must be calculated to determine the certain wind speed probability. Many problems will come if there no analysis the characteristics of wind in selected location, such as wind speed that not suitable for building wind farm to supply the population in that area. Shape and scale factors, which be controlled in a variety of ways, influence the Weibull distribution. Many studies have looked into which of the various Weibull parameter estimation methods is the most dependable. However, because the results of these investigations were inconsistent, research into more trustworthy Weibull parameter estimation methods is still ongoing. An analysis of data collected Chuping, Perlis for two years was conducted in this study (from 2018 to 2019). By using statistical analysis to evaluate the Weibull distribution method, this study used three methods to compared the Weibull parameters and identified the most reliable and effective method to obtain the Weibull probability distribution by using a three approach that compares the variances of RMSE, MSE and R2, which provides comprehensive insight into level error and volatility. Modified maximum likelihood method, graphical method, and power density method are the three methods used in this study. Therefore, the graphical method has the best accuracy in the wind speed distribution prediction, several methods such as the modified maximum likelihood method, and the power density method have the worst prediction of the wind speed distribution based on all the statistical method variances for this region.

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Synchronized cell balancing charging of supercapacitors using PI control

2020 , M.A Rashed , Muhammad Izuan Fahmi Romli , M M Azizan , C L Wai , Leow Wai Zhe , N F Rosle

This paper covers the synchronized cell balancing charging of supercapacitors using pi control. The main objective of this project is to design a balanced circuit for supercapacitor and balance the voltage for each supercapacitor in series using pi control. This project aims to introduce a switch resistor design for a supercapacitor to balance the cell. Due to its low cost, easy to implement, and charge/discharge, the switch resistor design was chosen as the balanced circuit. The switch resistor design process was accomplished taking into account all the calculation for the design parameters. Using the pi control given to the circuit the stability and balancing in the voltage. The pi control design process was accomplished with the calculation for the design parameters.

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Understanding Domain Knowledge in Initialization Method for K-Mean Clustering Algorithm in Medical Images

2022-01-01 , Tan X.J. , Nazahah Mustafa , Mohd Yusoff Mashor , Ab Rahman K.S. , Wan Zuki Azman Wan Muhamad , Leow Wai Zhe , Cheor Wai Loon , Oung Qi Wei

This work serves as a preliminary study to investigate and identify the applicability of domain knowledge as an initialization method for K-Mean (KM), typically in medical images. For this purpose, 20 breast histopathology images were used as data set and the evaluations are focused on the clustering of the hyperchromatic nucleus. The iteration numbers and clustering results (i.e., accuracy, over-segmentation, and under-segmentation) are benchmarked with KM++ and the conventional random initialization method. The domain knowledge initialization method is found promising by achieving lower iteration numbers (<9), higher percentage in accuracy (85.5% (±2.27)), and lower percentages in over-segmentation (8.25% (±2.23)), and under-segmentation (7.00% (±2.14)). From this study, we hypothesize that the domain knowledge initialization method has the potential to be implemented as an initialization method and is posited to overperform some established initialization methods, typically for clustering tasks in medical images.

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A Potential Controller for Smart Electrical Energy Management System

2021-06-11 , Kumuthawathe Ananda-Rao , Mohd Alif Ismail , Afifah Shuhada Rosmi , Leow Wai Zhe , Surina Mat Suboh , Muhammad Izuan Fahmi Romli , Abdullah A.M.

Integrated energy utilization has been recognized as a productive way towards better energy management, besides increasing Renewable Energy (RE) penetration. Thus, the combination of RE integrated with the Battery Energy Storage System (BESS) has been recognized as the primary solution where it is necessary to have a controller to interface the system efficiently. Hence, a smart electrical energy management system controller is designed and developed based on load leveling and peak shaving applications for real-time AC power management in this work. The main function of the controller is to continuously monitor and maintain the load demand and to produce a leveled or shaved load profile that will be seen at the grid network by controlling the battery operation. The testing results concluded that the controller able to perform both the energy applications. Overall, a dual function controller based on energy applications to maintain consumer load demand usage more securely and reliably, so that the utility bill is reduced and the battery lifetime is prolonged simultaneously is achieved in this work.

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Development A Portable Solar Energy Measurement System

2021-07-26 , Atika Z. , Leow Wai Zhe , Iszaidy I. , Mohd Irwan Yusoff , Safwati Ibrahim , Muhammad Irwanto Misrun , Wafi N.M. , Saw S.X.

This project presents the design and development a portable measurement device for measure and monitor solar panel parameters by using Internet of Things (IoT) concept. Solar energy measurement plays a very important role in the measurement of parameter reading for the determination of output generated, but the challenge is only performed manually at the work site using a clamp meter or a multimeter. Furthermore, it was very difficult to get the value at that time, and the data recovery error occurred. There are three specific objectives have been used for the project. Firstly, the relevant circuits for this project are design and built the circuit by using software. The output of the measurement solar irradiance, ambient temperature, solar panel temperature, current and voltage value were displayed on LCD. Next, IoT concept is used for solar panel measurement and monitoring. The value of the measurement and monitoring is used ThingSpeak cloud and ThingView application on the smartphone. It can be collected the portable solar for the energy measurement system can monitor on site, anywhere and anytime using IoT platform.

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Analysis on the Effect of DC Current Changes on the Magnetic Field of Wireless Power Transfer

2023-01-01 , Muhammad Irwanto Misrun , Ali M.B. , Nugraha Y.T. , Baharuddin Ismail , Nisja I. , Leow Wai Zhe

The generation of electromagnetic radiation in a solenoid, driven by alternating current (AC) voltage, is directly influenced by the voltage and current flowing through the solenoid. Exploiting this concept, wireless power transfer (WPT) systems can be developed. These systems consist of a sending coil and a receiving coil, both equipped with solenoids. The sending coil is connected to a half bridge circuit to generate AC voltage, which is then transmitted to the receiver coil. In this study, the effects of various factors on the performance of the wireless power transfer system were investigated, with a particular focus on the impact of DC voltage and input DC current. To examine these effects, an experimental setup was employed where the transmitter and receiver coils were powered by a DC voltage source. By varying the voltage and current parameters, the study aimed to analyze their influence on the wireless power transfer process. The simulation results show that 100 V and 150 V of DC current will produce 36.54 A and 54.8 A of input DC current respectively with constant resistor 7.54×10-2 Ω. The result shows that the input DC current is directly proportional with the magnetic field, AC current at sending and receiving coil, voltage at sending and receiving coil and AC power at receiving coil. Increasing the input DC current will increase the magnetic field, AC current at sending coil and receiver coil, voltage at transmitter coil and receiving coil and AC power at receiving coil and vice versa.

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Fault detection and classification in three phase series compensated transmission line using ANN

2020 , Norfadilah Rosle , Noor Fazliana Fadzail , M I A Halim , Mohamad Nur Khairul Hafizi Rohani , Muhammad Izuan Fahmi Romli , Leow Wai Zhe , Nur Najihah Abu Bakar

Series compensation consists of capacitors in series is used in the transmission lines as a tool to improve the performance after disturbed by a fault. Transmission line needs a protection scheme to protect the lines from faults due to natural disturbances, short circuit and open circuit faults. The fault can happen in any location of transmission line and it is important to know which location has been affected. So that, the fault can be eliminated and can maintain the optimum performance. Therefore, in this paper Artificial Neural Network (ANN) is used to detect and classified the fault happen in single line to ground fault and three phase to ground fault. Two different tests of each types of fault have been tested in order to prove the effectiveness of ANN to detect the fault location by using different length and fault resistance. The simulation has been accomplished in MATLAB with ANN fitting tool which build and train the network before evaluated its performance using regression analysis. The analysis shows that the ANN can accurately detect the different types of faults and classified it into the respective category even the random vectors are put on the system are used.

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Improvement of the photovoltaic output performance using hybrid active and passive cooling system

2017 , Leow Wai Zhe

This thesis presents the improvement of the photovoltaic (PV) output performance using hybrid active and passive cooling system. The PV technology has been used for several years and has proven successful for power generation, but the challenge is to adapt to local environment conditions, mainly caused by changes in weather conditions. Furthermore, the output power of the PV panel decreases as the operating temperature of the PV panel increases. Therefore, the main purpose of this current research is to design various types of cooling system in order to improve output power of the PV panel. This study has four specific objectives. Firstly, the effects of weather conditions on the thermal behaviour of PV panels were studied using simulation and experimental methods. In the simulation study, the effect of weather conditions in the thermal behaviour of the PV panel was simulated using CATIA and ANSYS simulation software. This study was conducted based on the weather of Centre of Excellence for Renewable Energy (CERE), UniMAP, Malaysia. It was shown that as solar irradiance and ambient temperature increased, the operating temperature of the PV panel increased. As the wind speed increased, the operating temperature of the PV panel decreased. In the experimental study, the dust appearing on the surface of the PV panel resulted in a decrease in the performance of the PV panel. However, the presence of wind on the surface of the PV panel resulted in an increase in the performance of the PV panel. Secondly, the PV panels with various types of cooling system were designed and simulated using ANSYS simulation software in order to analyse their thermal behaviour under weather conditions of CERE, Perlis. This included direct current (DC) fan cooling system, DC water pump cooling system, paraffin wax cooling system, hybrid DC water pump and paraffin wax cooling system as well as hybrid DC water pump and DC fan cooling system. The results showed that the PV panel with hybrid DC water pump and DC fan cooling system has the lowest operating temperature of 35.43 °C compared to other PV panels.

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