Liew Hui Fang
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Preferred name
Liew Hui Fang
Official Name
Hui Fang, Liew
Alternative Name
Fang, Liew Hui
Liew, Hui Fang
Liew, H. F.
Fang, L. H.
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Scopus Author ID
55987930400
Researcher ID
AAF-4915-2021

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  • Publication
    Numerical analysis of comparison highly efficient active rectifier for energy harvesting application
    (IEEE, 2023-08)
    Liew Hui Fang
    ;
    Diyya Hidayah Abd Rahman
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Mohd Arif Mohd Zain
    ;
    Junaidah Ali Mohd Jobran
    ;
    Norhanisa Kimpol
    A piezoelectric energy harvesting (PEH) circuit with a passive rectifier lack in efficiency and performance. The performance and potential of piezoelectric energy-harvesting devices depend strongly on the power conditioning circuit as the circuits are essential for managing and controlling energy flows in these energy collecting devices. In order to overcome this situation, the parallel synchronized switch harvesting on inductor (P-SSHI) and the general model of synchronized multiple bias-flip (SMBF) which are the recent implementation of parallel synchronized triple bias-flip (P-S3BF) and parallel synchronized septuple bias-flip (P-S7BF) are used for further enhancing the PEH performance. In addition, active rectifiers presented distinguished benefits over passive rectifiers, such as the ability to analyze regulation, dynamic response to load changes, output voltage ripple, input current, total harmonic distortion (THD), power factor correction, and wave factor. Furthermore, by using an active rectifier the output voltage can be boosted higher. Thus, it is more efficient than a lower voltage since it experiences less energy loss from resistance. This research investigates the several high efficiency AC-DC active rectifiers as interface circuit plays a crucial role in the energy harvesting capability enhancement in PEH systems. The research methodology is carried out on a piezoelectric structure under the same base circuit with a different type of power conditioning circuit applied to the main circuit using the LTspice software. In conclusion, the input voltage for each different active rectifier circuit were set at 3-5 V and the frequency is set based on the input voltage of the circuit. Based on the results, the P-S7BF shows the higher efficiency with voltage output will have the most efficiency with the estimated voltage output reaching up to 13 V with a net harvesting power of up to 80-90% follow up by the P-S3BF and P-SSHI. There are several recommendations to improve active circuit by investigation the impact of load variation on the efficiency, such as different loads may require different rectification techniques and control strategies to achieve high efficiency.
  • Publication
    Supercapacitor’s parameter calculation based on three branch equivalent circuit model under different constant charging current
    (IOP Publishing, 2023)
    Makhdoom Abdul Jabbar
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Shamshul Bahar Yaakob
    ;
    Liew Hui Fang
    ;
    Md Shahrukh Adnan Khan
    Supercapacitor is a type of energy storage with higher capacitance value compared to the normal capacitor. But it has lower voltage level compared to normal capacitor. However, it can be charged with high current and provide higher current to the load when needed when compared to the same size energy storage such as battery. The Three Branch Equivalent Circuit is one of the simple yet accurate model that has been proposed. The parameter of the Three Branch model included the capacitance, resistance and a unit of voltage dependent capacitance. The Parameter needed to be calculated accurately as it depends heavily on the terminal voltage of the supercapacitor at respective time which obtained through a charging and self-discharging experiment under constant current charging. The different constant charging current give effect toward the parameter calculation as it manipulates the rate of charging and self-discharging. This paper will calculate the parameter of supercapacitor based on the Three Branch model under different constant charging current and compared the result using the simulation to show the accuracy of the model. The parameter obtained throughout the study shows a high accuracy especially the parameters obtained using higher charging current.
  • Publication
    Total Harmonic Distortion Comparison Analysis between High-Power Density Inverter and Multilevel Inverter
    ( 2021-01-01)
    Khalid K.A.
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Liew Hui Fang
    ;
    Muhammad Zaid Aihsan
    ;
    Mohd Saifizi Saidon
    The inverter is one of the most common things in converting electrical energy supply and it is a very important concept in the current modern electrical power system to utilize the maximum potential by generating the unit while considering the environment within the surrounding area and avoid pollution is the most ideal concept of energy management. The main purpose of this study is to consider which one of the inverters is more suitable for energy saving. There are two kinds of inverter that have been tested for this research which are the High-power density inverter (HPDI) and Multilevel inverter (MLI). In High-power density inverter (HPDI) it uses electrical components such as Insulated-gate Bipolar Transistor (IGBT) as the main component. As for the Multilevel inverter (MLI) it uses electrical components Metal- oxide-semiconductor field-effect-transistor (MOSFET) as the main component. Both inverters are being implemented and running by using MATLAB Simulink software. Besides that, the result is obtained by comparing the Total Harmonic Distortion (THD), the output of the waveform and energy efficiency for both inverters.
      6  25
  • Publication
    Experimental study of Bipolar PV Inverter for nonlinear load
    ( 2021-07-26)
    Muhammad Zaid Aihsan
    ;
    Fahmi M.I.
    ;
    Liew Hui Fang
    ;
    Wan Azani Wan Mustafa
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Mohd Aminudin Jamlos
    One of the attractive options for converting solar PV DC/AC modules is a bipolar inverter as bipolar technique provide easy control and theoretically low-priced technology. A few drawbacks to this bipolar method, since it has a high voltage DC-link ripple, which can cause high harmonic inverter distortion. A smooth DC voltage is then needed to preserve the unstable voltage of the PV device in such a way that the overall harmonic distortion of the inverter is preserved at the regular stage. This paper will demonstrate the impact of unstable voltage from PV and connecting to the nonlinear load. The performance of the converter in term of efficiency and THD performance are monitored and reported.
      4  22
  • Publication
    Review Article: Voltage Balancing Method for Battery and Supercapacitor
    ( 2023-02-01)
    Nordin N.N.S.
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Liew Hui Fang
    ;
    Muhammad Zaid Aihsan
    ;
    Mohd Saifizi Saidon
    This paper examines several existing voltage equalizers techniques for energy storage system, with a focusing on batteries and supercapacitors. Due satisfy the demands, energy storage cells are often coupled in series/parallel. However, divergence of voltage distributed among cells produces the problems of voltage imbalance that affecting the ageing of energy storage system and solved through equalizers. Several assessments from features of topologies in voltage balancing circuit supplied primarily based total on a few attentions’ just like the effectiveness in balance and components. Voltage balancing is essentially separated into two categories: passive and active equalizers. Therefore, this paper studied and reviewed several topologies from both equalizer types with the sample result to verify the topology performance.
      15  28
  • Publication
    Review of feasibility wind turbine technologies for highways energy harvesting
    (IOP Publishing, 2020)
    Liew Hui Fang
    ;
    Baharuddin Ismail
    ;
    Abd Rahim, Rozemizi
    ;
    Muzamir Isa
    ;
    Hassan, Syed Idris Syed
    Wind energy is one of the non-conventional forms of energy and it is available in affluence. It is also claimed that the wind power is pollution-free, replacement of fossil fuel and that its source of energy is freely available. Electricity can be generated with the help of a wind turbine generator. In this paper, a comprehensive study on contemporary portable wind energy harvesters has been conducted. The different existing performance such as reliability evaluation models, various problems related to structure wind turbine components (blade, gearbox, generator and transformer) and grid for wind energy system have been discussed. At the same time, experimental analysis is focused on behaviour, especially characteristics of impact wind energy, performance as lots of advanced research work has already been done or going on the harnessing of natural wind energy. In this review paper, a different model wind turbine has been studied from previous testing purpose presented. This review aim of utilizing this wind energy in a most effective manner to get the maximum electric output, and therefore the government can think over implementing the suitable type of wind turbine configuration selected highway at low cost as our installation site taking the advantage of the moving vehicles on both sides of the road.
      12  1
  • Publication
    Solar powered multiple output buck converter
    (IOP Publishing Ltd, 2020)
    Muhammad Zaid Aihsan
    ;
    Norhanisa Kimpol
    ;
    Liew Hui Fang
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Wan Azani Wan Mustafa
    ;
    Junaidah Ali Mohd Jobran
    ;
    Mohamed Mydin Hj M.Abdul Kader
    Times have certainly changed over the past few decades, now it seems that technology is getting more compact and efficient. The modern outdoor enthusiast such as hikers, climbers has a problem regarding the lack of power supply to power up electronics when they go for adventure activities. In order to solve this problem, this paper design and develop DC/DC buck converter system to drop down the voltage from the solar photovoltaic (PV) system from 12VDC into 5VDC. This paper is first to start up with design and simulation circuit using simulation to test outcome of this paper in the range of 5VDC & 1.0A and 5VDC & 0.5A. A battery storage is needed to feed electricity independent and battery management of the battery is needed to improve the performance of battery life. This can be done by adding a charge controller unit. The outcome of this paper allows the battery to be charged using the solar panel and at the same time can produce multiple outputs for low voltages used. The software simulation has been done to shows this system produces two different output and the hardware will be developed based on the software results. Software and hardware result, both will be compared and analysed.
      1  18
  • Publication
    Piezoelectric Array Configuration Technique into Enhance Power Catchment for Sound Energy Harvester System
    ( 2020-11-18)
    Liew Hui Fang
    ;
    Rosemizi Abd Rahim
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Mohamad Zhafran Zakariya
    ;
    Junaidah Ali Mohd Jobran
    ;
    Norhanisa Kimpol
    The objective of this study is to explore the harvest maximum output changes occurs in piezoelectric transducer when connected in different configuration to produce highest electricity consumption and generate sound energy harvesting system. Acoustic energy is a type of environmental energy source that can be extracted and converted into electrical energy for small-scale energy applications. In this study, the corresponding load resistance for single piezoelectric transducer is 4.5 k$\Omega$, together with a constant vibration source at a frequency of 68 Hz and a 1-g acceleration. The performance of output voltage and power of piezoelectric are evaluated and the optimum output is measured by depending on the connection of the piezoelectric transducer arrangement into series, parallel and series, and parallel which stimulated using Proteus software. The experiment result presented that, when have single piezo, 5 piezo connected in series, and 5 piezo connected in parallel, the output powers are 1.664 mW, 1.671mW and 7.676 mW, respectively. During the combination series and parallel connections, the output power of 3S1P piezo increases to 5.05mW. In a parallel configuration, the output voltage that produced is much higher than a piezoelectric transducer arrangement connected in series connection. The piezoelectric transducer that connected in parallel configurations increases its voltage output from 2.83 V to 13.05 V with the same polarity. The arrangement of piezoelectric transducer in parallel configuration is affordable, with its higher production of a higher power output compared to the arrangement of piezoelectric transducer in series connection. Whereas in terms of power output, the maximum power remains constant in the range of 1.665 to 1.671 mW when three transducers are in series configuration connection with the same polarity. In conclusion, the proper implementation of the piezoelectric array configuration is needed in order to operate the minimum energy for low load devices and promise to accomplish generated optimum power output in harvester system.
      6  52
  • Publication
    Performance Evaluation of Transformerless Inverter based Quadratic Boost Converter
    ( 2021-01-01)
    Muhammad Zaid Aihsan
    ;
    Muhammad Izuan Fahmi Romli
    ;
    Liew Hui Fang
    ;
    Wan Azani Wan Mustafa
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Al-Abbooda K.S.
    This paper presents a single-phase transformerless inverter based high step-up quadratic boost converter (QBC). By removing the conventional isolation transformer in the single-phase inverter system is grants higher efficiency and reduction in size as well as cost-effectiveness. The proposed topology can generate a standard single-phase power rating of 230 Vrms from a small dc voltage. The capability of the quadratic boost converter to perform a single-stage boost operation is guaranteed before inverted to the alternating sequence of Ac voltages as the constant duty cycle and proper unipolar modulation technique are well implemented. Experimental results are presented to verify the proposed topology capability.
      1  31
  • Publication
    Environmental noise harvester for low voltage power supply
    ( 2018)
    Liew Hui Fang
    There is an increased awareness nowadays regarding the potential shortage of fuel sources for electricity generation in the future, where various studies have been conducted about the usage alternative sources. Currently, the renewable energy has been prioritized for instance, through ambient energy scavenging. To achieve this goal, sound, being the most abundant energy in the environment, is likely the best candidate to fill the slot. The existing rectifying technique that has been used for energy transfer in energy harvesting is ‘switch-only’ and ‘bias-flip’ techniques which is utilize an additional switches or switched inductors for speedy voltage rectification. However, such techniques depend on the timing accuracy and synchronization of the pulses of the switch whenever the changes in the currents' polarity generated by the piezoelectric harvester. The existing acoustics-based energy harvesting systems utilized a self powered active rectifying diode circuitry technique to converts alternating current signal to direct current. The active MOSFET rectifier circuit has extra components and required an external DC supply to powering the rectifying circuit. Thus it is not a good option for small scale harvester system and suffered some drawbacks in the implementation of the circuit. Although synchronous switch harvesting on the inductor(SSHI) and synchronous electric charge extraction (SECE) rectifiers possess high efficiency to extract and harvest the energy available from system, they have drawbacksof SSHI circuits such as the complexity of the circuit which is can contribute to additional losses of power, threshold voltages, frequency selectivity and parasitic bandwidth filters. In this study, the developments of passive circuit including voltage multipliers (Dickson and Villard circuits) and step-up transformer were proposed and designed to rectify the low voltage acoustic voltage. The simulation of the proposed harvesting circuit was performed using Multisim and Portus simulator. For verification purpose, the PZT-5A piezoelectric transducer model has been chosen as the harvester due to the consistency. During the experiment, the resonance frequency of the harvestersystem was at 68 Hz with the 95 dB of acoustic pressure. The experimental results showed that the output closed-circuit voltage and the output power harvester can reach up to 3.894Vrmsand 1.556mW respectively. The passive AC-DC harvesting circuits can probably achieve the overall energy conversion efficiency by 78.9% (Dickson circuit) (1.228mW), 70.5% (Villard circuit) (1.097mW), and 10.1% (step-up transformer) (0.1564mW) respectively. Based on the results presented above, the proposed energy harvesting systems seem to be promising and possess a good potential to be used in low power sensors such as wireless sensor networks.
      7  20