Boon Han Lim

Universiti Tunku Abdul Rahman | utar · Department of Electrical and Electronic Engineering

The assessment of research performance is widely seen as a vital tool in upholding the highest standards of quality, with selection and competition believed to drive progress. Specifically, academic institutions need to take critical decisions on hiring and promotion, while facing external pressure by also being subject to research assessment [1–4]...

span lang="EN-US">The extensive use of power electronic converters in the third rail system increases the harmonic distortions on the rail electrical feeding systems. Electrical machines and transformers could be overheated causing premature failures of the devices. It is therefore important to address the harmonic distortions on the electrical net...

This paper proposes a mobile sun-tracking (MST) system to track the sun on the moving vehicle. We have developed a novel MST algorithm using general sun-tracking formulas associated with simple-moving average linear regression (SMALR) to smoothen sun-tracking activity. Furthermore, two different timing control schemes to activate sun tracking are i...

Fair division captures many real-world scenarios and plays an important role in many research fields including computer science, economy, operations research, etc. For the problem of indivisible goods allocation, it is well-known that an allocation satisfying the maximum Nash Social Welfare (Max-NSW) is envy-free up to one good (EF1), which is an i...

Recently, contrastive learning has gained increasing attention as a research topic for image-clustering tasks. However, most contrastive learning-based clustering models focus only on the similarity of embedded features or divergence of cluster assignments, without considering the semantic distribution of instances, undermining the performance of c...

In today's information age, both excess and lack of information can cause a disaster. COVID-19 pandemic not only highlighted the significance of risk communication but also pointed out several unintended and distressing consequences due to information gaps and miscommunications. Despite facing a common threat, the local communities suffered differe...

A complete dataset of ground-measured Global Horizontal Solar Irradiance (GHI) is vital for the design and performance assessment of a photovoltaic (PV) system. Hence, imputing the missing values of the dataset can be a cost-effective solution for a site that already has ground-based measurement devices installed when satellite-derived data cannot...

A dual-axis sun tracking system is an essential strategy to maximize the optical efficiency of harnessing solar energy. However, there is no significant study yet to optimize the net performance of the photovoltaic (PV) or concentrator photovoltaic (CPV) system equipped with a dual-axis sun tracking system. Parasitic energy loss associated with the...

Passive design involves the utilization of natural forces such as natural ventilation and daylighting without mechanical input of energy, and is a subset of environmentally sustainable design (ESD), which offers solutions for more environmentally friendly buildings. This review is based on the premise that ESD interventions have an inherent cost on...

Significant investment risks of large photovoltaic (PV) systems are uncertainties of energy yield predictions from a PV power plant. Unfortunately, solar irradiance weather datasets often have missing values due to operational issues; hence techniques of imputing or recovering the missing values become essential. This paper examined five statistica...

Global solar irradiance (GHI) data plays a major role in the design, performance assessment, and monitoring of a solar energy conversion system. However, data loss happens sometimes due to various reasons. Hence, it is important to recover the lost data. Unfortunately, due to the high cost of measurement devices, other meteorological parameters are...

A dual-axis tracked Photovoltaic (PV) system can produce up to 30% more electrical energy in a year as compared to a fixed-tilt PV system. To be economically feasible, a sun-tracker must also be accountable for the cost effectiveness, durability and long-term reliability despite the gain in electrical yield. To achieve this purpose, in this paper,...

The temperature rise of solar panels can cause significant reduction in the energy generation especially for the countries located in tropical climate region. It is more effective to use water-film for cooling the front surface of solar panels, but the energy consumption of the water-cooled photovoltaic system (WCPV) needs to be reduced to obtain a...

Inappropriate layout design of concentrator photovoltaic (CPV) systems in the solar field will incur optical losses due to mutual shadowing among adjacent CPV systems. This will deteriorate the energy generation of a solar power plant (SPP). The trivial solution is to increase the separating distance between adjacent CPV systems. Unfortunately, it...

Electricity is one of the indispensable elements in the daily life. From domestic to commercial sector, electricity has been used to provide a wide range of applications. However, access to electricity is only limited to the urban area while rural area electrification is always a challenge due to the geographical location and high cost of the elect...

This paper presents the performance evaluation in terms of optical and electrical characteristics of the crossed compound parabolic concentrator (CCPC) module for the application of the ultra-high concentrator photovoltaic (UHCPV) system. The CCPC module is the integration of a dielectric-filled 3D CCPC lens and a multi-junction solar cell (MJSC) m...

The performance of a crystalline silicon photovoltaic (PV) system is greatly reduced with the increase of the temperature of the solar panels, especially in the tropics. In this study, a water-film cooling system was installed onto a retrofitted rooftop PV system, which is operating as a distributed generation system. The experiment shows that this...

In this paper, we analyse the performance of newly proposed hybrid dense-array concentrator photovoltaic (CPV) and gamma type low temperature differential (LTD) Stirling engine. Schmidt Analysis was applied to compute the performance of LTD Stirling engine while computational fluid dynamic was employed to simulate the heat transfer in the CPV recei...

Despite the sun-tracking system maximising the annual yield of solar power generation, the inevitable parasitic energy losses from the sun-tracking mechanism related to range of motion should be considered. This paper presents a systematic approach to investigate the annual accumulated parasitic energy losses in photovoltaic (PV) or concentrator ph...

This paper proposes a mobile sun-tracking system, which allows continuous tracking of the sun and effective harvesting of solar energy on mobile platforms. Based on the dynamic sun-tracking algorithm which we previously proposed, the system takes not only the date, time, and geographical information, but also the dynamic changes of coordinates of t...

This paper presents a systematic approach for optimizing the design of ultra-high concentrator photovoltaic (UHCPV) system comprised of non-imaging dish concentrator (primary optical element) and crossed compound parabolic concentrator (secondary optical element). The optimization process includes the design of primary and secondary optics by consi...

The paper presents a novel dense-array concentrator photovoltaic prototype system consisted of primary non-imaging dish concentrator and secondary concentrator (an array of crossed compound parabolic lenses). The secondary optics has a geometrical concentration ratio of 5.998 but the average measured concentration ratio is only 4.07 suns. The losse...

Solar farms are considered as easy target for thieves because of insufficient protection measures. Existing anti-theft approaches are based on system level and are not very preventive and efficient because these can be bypassed with some technical knowledge. Additionally, it is difficult for security guards to tackle them as robbers come in a form...

Intermittent nature and low efficiency are the major issues in renewable energy supply. To overcome these issues, one of the possible methods is through a hybrid system where multiple sources of renewable energy are combined to compensate each other’s weaknesses. The hybrid of solar energy and waveenergy becomes possible through the introduction of...

In this paper, we would like to report on a prototype of dense array concentrator photovoltaic (DACPV) system including the practical implementation and economic assessment. The newly proposed system consists of primary concentrator in the form of non-imaging dish concentrator and secondary concentrator as an array of dielectric filled crossed comp...

Luminescence mediums: samarium ion and yttrium ion, were introduced to expand the photo-response region of TiO2 by means of the down-conversion effect to convert ultraviolet light into visible light, offering a unique method to enhance the photovoltaic performance of dye-sensitized solar cells (DSSCs). Their crystal structures, optical properties a...

A comprehensive study of the latitude-orientated configuration of non-imaging focusing heliostat (LO-NIFH) is reported. In this configuration, we have made the sun tracking formulas of a non-imaging focusing heliostat (NIFH) to be independent of the latitude where it is installed; hence we name it a latitude oriented non-imaging focusing heliostat...

A down-conversion (DC) photoelectrode of TiO2:Sm3+ nanocrystals synthesized by sol-hydrothermal method was introduced on dye-sensitized solar cells (DSSCs) to investigate the effect of DC nanocrystals in DSSCs. X-ray diffraction (XRD), energy disperse spectroscopy (EDS) and Brunauer-Emmet-Teller (BET) analysis were employed to characterize the stru...

Optical and electrical analyses of non-imaging dish concentrator (NIDC) with secondary concentrator for the application in dense-array concentrator photovoltaic (CPV) system are presented. Array of crossed compound parabolic concentrator (CCPC) lenses is selected as secondary concentrator due to high acceptance angle, larger entrance aperture to pr...

Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using...

This paper proposes a novel dynamic sun-tracking algorithm which allows accurate tracking of the sun for both non-concentrated and concentrated photovoltaic systems located on mobile platforms to maximize solar energy extraction. The proposed algorithm takes not only the date, time, and geographical information, but also the dynamic changes of coor...

Using a new type of solar furnace and a specially designed induction furnace, cost effective and highly efficient purification of metallurgical silicon into solar grade silicon can be achieved. It is realized by a new method for extracting boron from silicon with the aid of photo-chemical effect. In this article, we discussed the postulated princip...

In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberration free optical devices. The tip-tilt of facet in a mirror array is produced by digitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical p...

By direct calculation of rotation matrices of SO(3), we show how certain specific sequence of eight consecutive rotations of digital angles can yield a tilting of a facet mirror. We also design a detailed program specifically to tilt an array of mirrors from planar orientation to the required focusing orientation. We describe how to use the 8-step...

We propose a new method to reveal a direct transformation from solar energy to solar electricity. Instead of using electricity in the process, we use concentrated solar rays with a crucibleless process to upgrade metallurgical silicon into solar-grade silicon feedstock.

A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuth-elevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general...

The most general form of solar tracking formulae of an arbitrarily oriented heliostat toward an arbitrarily located target on the Earth is presented. With this complete solution, the used azimuth-elevation, spinning-elevation tracking formula, etc., are the special cases of it. Therefore, more application may be sought out for many individual cases...

A new fixed aberration correction surface for applications in solar energy is proposed. The surface equation was derived based on the theory of focusing heliostat and the technique of canting the mirror array at a particular incident angle. The performance of the optimized new surface is simulated and compared with that of a spherical surface for t...

Following our previous report on the first prototype of non-imaging focusing heliostat, this second prototype has presented much improvement not only in the respect of structure but also in the method of controlling. The principle and practice of these changes have been reported in the article. The development of the new heliostat which is closer t...

The basic mathematics and structure of heliostat have remained unchanged for many decades. Following the challenge first made by Ries et al., the non-imaging focusing heliostat recently proposed by Chen et al. provides an alternative in the field of concentrated solar energy. This paper investigates the performance of a heliostat field composed of...

A new method of reflectivity measurement for the study of reflective materials in solar energy technology is reported in this paper. The method employs a fast rotating reference mirror and certain geometry configuration to alternatively deliver the light via a sample mirror or by passing it to a photo detector. It has been proved to reach a precisi...

Instead of using a specific focusing geometry, a non-imaging focusing heliostat has no fixed geometry but is composed of many small movable element mirrors that can be manoeuvred to eliminate the first-order aberration. Following our previous publication on the principle of non-imaging focusing heliostat, this paper further explores higher order re...

Following the publication on the principle and theory of a newly proposed non-imaging focusing heliostat, this paper presents a report on the design, optical alignment and application of the first prototype heliostat. In the architecture of the first prototype, 25 mirrors, each with a dimension of 40×40cm, are arranged into five rows and five colum...

A non-imaging focusing heliostat for effective use of thermal solar energy is proposed. The heliostat consists of a number of grouped slave mirrors, which are able to move according to a proposed formula to eliminate the first order aberration. The master mirror tracks the sun by a proposed rotation-elevation mode to project solar rays together wit...

After reviewing the research work of gravitational wave detection in the laboratory, particularly long base laser interferometer detectors, the authors report on the recent progress of gravitational wave detection using laser interferometer (Tianyin-100) in Malaysia. The authors also outline the brief plan for Tianyin-500 in the future as a full-sc...

A new method of reflectivity measurement is proposed and tested in this Ph.D. study. The method employs fast rotating reference mirror and certain geometry configuration to alternately deliver the light via a sample mirror or by passing it to a photo detector. It has proved to reach a precision of 2 x lo4 reflectance unit. The precision is at least...