Wan Nor Liza Binti Wan Mahadi

Thermal Analysis of a Tubular Permanent Magnet Linear Generator using Multiphysics Solver

This paper presents the thermal design aspect of linear generator. A study is carried out to investigate the temperature effects on the components in linear generator. One of the most important components in the linear generator, neodymium Iron boron (Nd-Fe-B) permanent magnet is emphasized in this study since it provides a magnetic field source for the linear generator and the influence of its electromagnetic properties towards temperature will affect the performance of linear generator. In this paper, the generator is coupled with the internal combustion engine which tends to produce heat. Due to the high temperature from the combustion engine and the heat produced by the current carrying conductors, thermal analysis on different physical aspects has been done. In order to achieve an accurate result, the multiphysics solver is used to analyze the thermal analysis for both electrical and thermal problem. Finite element method (FEM) is used to observe this coupled field effect.

A review on electromagnetic suspension systems for passenger vehicle

This paper discussing all the design literature review for electromagnetic suspension systems for passenger vehicle. Electromagnetic suspension is the alternative for existing conventional suspension system that uses passive suspension system. Generally, linear motor is used in the design of the suspension. This is due to the behavior of the motor that can exert linear force directly to the attached load. In addition, the linear force from linear motor is controllable. This paperreview with the effects of all types of electromagnetic suspension systems to the passengers comfort. The reliability of fully active suspension system for vehicle also highlighted in this paper. A quarter-car model is used to assess the vehicle body vibration. This paper also deals with regenerative properties of linear motor that can improve the performance of lightweight vehicle.

A review on control strategies for passenger car intelligent suspension system

The main function of a suspension system is to reduce/isolate vibration caused by road irregularities to improve comfort, reliability and road holding of the vehicle. In this paper, various control aspects in controllable suspension are reviewed focusing on suspension performance criteria, control strategies and control methodologies. This includes the implementation of software-in-the-loop (SIL) and hardware-in-the-loop (HIL) simulations. Based on these reviews, a study on a suspension system control strategy with implementation of the HIL and SIL simulations approach is proposed for future works.

A Low-Profile Patch Antenna for Ultrawideband Application

In this letter, a low profile stacked patch antenna is proposed for UWB operations. The antenna design is comprised of three patches; a 35° angularly folded patch feed (bottom patch), T-shaped patch (middle patch), and strip-loaded patch (top patch). The wide bandwidth is achieved with the integration of a 35° angularly folded patch feed with a T-shaped patch. The antennas size is reduced by using the shorting wall technique. The existence of electromagnetic coupling between the T-shaped patch and strip-loaded patch further improves the impedance bandwidth. The design exhibits a compact electrical dimension of 0.12λ×0.14λ×0.08λ, where λ is the wavelength of the lowest operating frequency. The measured results showed that the antenna can achieve a bandwidth of 107.46% (3.1-10.3 GHz). Acceptable gain, stable radiation patterns, and low group delay variation in the operating band are achieved as well. These measured results signify the effectiveness of the proposed antenna configuration in the context of UWB application.

Design of a Compact Tuning Fork-Shaped Notched Ultrawideband Antenna for Wireless Communication Application

A new compact planar notched ultrawideband (UWB) antenna is designed for wireless communication application. The proposed antenna has a compact size of 0.182λ × 0.228λ × 0.018λ where λ is the wavelength of the lowest operating frequency. The antenna is comprised of rectangular radiating patch, ground plane, and an arc-shaped strip in between radiating patch and feed line. By introducing a new Tuning Fork-shaped notch in the radiating plane, a stopband is obtained. The antenna is tested and measured. The measured result indicated that fabricated antenna has achieved a wide bandwidth of 4.33–13.8 GHz (at −10 dB return loss) with a rejection frequency band of 5.28–6.97 GHz (WiMAX, WLAN, and C-band). The effects of the parameters of the antenna are discussed. The experiment results demonstrate that the proposed antenna can well meet the requirement for the UWB communication in spite of its compactness and small size.

Aerogel Poly(butylene succinate) Biomaterial Substrate for RF and Microwave Applications

Polybutylene succinate (PBS) has become a potential candidate, similar to polypropylene (PP) and acrylonitrile butadiene styrene (ABS), for use as an organic plastic material due to its outstanding mechanical properties as well as high thermal deformation characteristics. A new composition of silica aerogel nanoparticles extracted from rice waste with PBS is proposed for use as a dielectric (εr = 4.5) substrate for microwave applications. A microstrip patch antenna was fabricated on the proposed dielectric substrate for multi-resonant ultra-wideband (UWB) applications. The performance characteristics of the proposed biomaterial-based antenna were investigated in a far-field measurement environment. The results indicate that the proposed biocompatible material-based antenna covered a bandwidth of 9.4 (2.3–11.7) GHz with stop bands from 5.5 GHz to 5.8 GHz and 7.0 GHz to 8.3 GHz. Peak gains of 9.82 dBi, 7.59 dBi, 8.0 dBi and 7.68 dBi were measured at resonant frequencies of 2.7 GHz, 4.6 GHz, 6.3 GHz and 9.5 GHz, respectively.

Extremely low frequency electromagnetic field (ELF EMF) survey of residential areas around transmission lines

Extremely low frequency (ELF) electromagnetic fields (EMF) are categorized as non-ionising radiation (NIR). They are generally generated by overhead transmission power lines. A study of ELF EMF was conducted at residential areas around the transmission line located at Kelang Valley. The objectives of the study were to determine the strength of the ELF EMF present besides to assess the potential exposure received by future residents. The surveys were carried out using PMM model EHP50A and EMDEX instruments based on standard measurement procedures and protocol recommended by IEEE. The results obtained were compared against the permissible exposure limits recommended by International commission of non-ionising radiation protection (ICNIRP) for members of public to ensure that they are acceptable in term of safety. This paper highlights some of the findings at the Study site. The results obtained indicates that the ELF EMF radiation level within the study area (outside ROW) generated by the power lines but their field strengths were within the permissible exposure limits by ICNIRP which were 0.03% and 5.26% for magnetic and electric field respectively. Both field strengths were found to drop very significantly against distance from the power lines where closer distances always showed higher field strengths.

Power transmission line magnetic fields: a survey on 120 kV overhead power transmission lines in Malaysia

The concern on electromagnetic fields (EMF) which may has detrimental effects on human health has heightened public awareness towards the overhead power transmission lines. Frequency of the electrical power lines is typically in the range of 50/60 Hz and yet is classified as extremely low frequency (ELF). Recent studies conducted, are concentrating mainly towards the existence of electric field intensity (E-field) and magnetic flux density (B-field). In this paper, emphasis is placed on the ELF magnetic fields because this is the subject that is believe to have more effect to human health. Basic properties of power lines are described and investigated. Spot magnetic field method was used for measurement, but varieties of methods are also being described here. The data obtained here are useful in order to provide the basic understanding of magnetic fields generated by the power transmission lines.

Using gear mechanism in vehicle suspension as a method of altering suspension characteristic

A passive vehicle suspension has constant spring and damper properties that compromise either ride or road holding ability, depending on whether the suspension is designed to be hard or soft. This study examines the implementation of a gear mechanism in a vehicle suspension system to alter its suspension characteristic while keeping the same spring and damper properties. In the study, a rack-and-pinion mechanism was used to modify the suspension force which acted between the sprung and unsprung masses of a quarter vehicle model. The system with proposed suspension layout was modeled mathematically and solved to obtain the vehicle response due to step excitation for various gear ratios. Results indicated that the use of such a mechanism was capable of changing the equivalent suspension force of the system. It was noted that different gear ratios would amplify or reduce the equivalent suspension force, hence emulating a harder or softer suspension setting compared to that of the original suspension. Additionally, it was found that with optimized gear ratio and gear mass, the implementation was capable of overcoming the compromise between the ride and road holding ability associated with conventional passive suspensions, as simultaneous improvement on both criteria was observed.

Mitigating voltage sag by implementing STATCOM on DFIG-based wind farms connected to a power system

Due to variation of environmental condition, power generated from a renewable source of energy always fluctuates. In the same way, by injection of wind power into the electric grid some power quality may varies because of a wind fluctuating inherent and relatively new types of generators. The measurements and the guidelines indicated in International Electro Technical Commission 61400 Standards the quality of power generated and the performance of wind turbines are derived. As far as the measurements of the generated power quality is concerned while the turbine is connected to an electrical grid there are certain associated powers such as active and reactive powers, flicker, the switching functions electrical behavior, voltage swell, harmonics and voltage sag. Their measurements are done according to national and international guidelines. Nowadays, grid connected doubly fed induction generator becomes an interesting topic for power engineers to focus on. Moreover, voltage stability becomes an important factor to maintain the DFIG-based wind farm functioning during disturbances. This paper studies the static synchronous compensator implementation in order to address the issue of voltage stability in wind farms connected to the distribution network. STATCOM is used as a dynamic reactive power compensator to stable the voltage at the point of common coupling by protecting DFIG-based wind farm interconnected to the distribution system from going offline throughout and after the disturbances. Results obtain shows that, during the voltage sag voltage drops to 0.7pu and after connection of STATCOM voltage will improve to 0.89pu. The developed system is simulated in MATLAB/Simulink and the results show that STATCOM mitigates the effects of transient disturbances such as, voltage sag in the system and hence improves the stability and performance of wind farm.