Showing 16 results for Mat
R. Naderi, A. Rahmati,
Volume 4, Issue 4 (October 2008)
Abstract
Multilevel PWM waveforms can be decomposed into several multilevel PWM
components. Phase-shifted carrier (PSC) is an efficient decomposition technique. In this
paper, we have first demonstrated the equality of PSC and alternative phase opposition
disposition techniques. Second, we have modified PSC to accommodate other disposition
techniques. Third, we have investigated the effects of using asymmetrical carriers on the
spectrum of the resulting PWM waveform. Fourth, we have proposed a logical algorithm
for decomposing all types of multilevel PWM waveforms.
A. Nemati, M. Pakdel,
Volume 6, Issue 3 (September 2010)
Abstract
A novel ZVZCS isolated dual series-resonant active-clamp dc–dc converter is
proposed to obtain high efficiency. The proposed converter employs an active-clamp
technique, while a series-resonant scheme controls the output voltage with the complementary
pulse width modulation controller. The active-clamp circuit serves to recycle the energy
stored in the leakage inductance or the magnetizing inductance and provides zero-voltage and
zero-current turn-on and turn off switching. The voltage stresses of the main switch are
clamped. The voltage transient spikes across the dual series active clamp circuit and the
current stress of the current-fed side switches are limited by auxiliary active clamping circuits
on both sides, and ZVZCS is achieved. The operating principles and design considerations are
discussed and verified by simulations using PSIM software. Also, the EMI reduction
techniques from EMC point of view in the circuits related to converters has been pointed out.
H. Torkaman, T. Hemmati,
Volume 14, Issue 1 (March 2018)
Abstract
This paper introduces a novel two transistors forward topology employing a z-source to achieve ZVZCS and power transformer resetting for various applications. Comparing with the forward converter, this topology has the advantage of displaying ZCS condition with an added Z-Source and no additional switches when the switches turn on, and that ZVS condition happens when the switches turn off. Duty cycle of the topology can exceed 50 percent. As a result, these converters are suitable for applications with high efficiency. In this paper, structure and properties of the topology will be discussed in details. Then the design principles will be presented. Finally, the benefits aforementioned will be approved in practice through a simple forward converter.
S. Heshmatian, D. Arab Khaburi, M. Khosravi, A. Kazemi,
Volume 14, Issue 1 (March 2018)
Abstract
Wind energy is one of the most promising renewable energy resources. Due to instantaneous variations of the wind speed, an appropriate Maximum Power Point Tracking (MPPT) method is necessary for maximizing the captured energy from the wind at different speeds. The most commonly used MPPT algorithms are Tip Speed Ratio (TSR), Power Signal Feedback (PSF), Optimal Torque Control (OTC) and Hill Climbing Search (HCS). Each of these algorithms has some advantages and also some major drawbacks. In this paper, a novel hybrid MPPT algorithm is proposed which modifies the conventional methods in a way that eliminates their drawbacks and yields an improved performance. This proposed algorithm is faster in tracking the maximum power point and provides a more accurate response with lower steady state error. Moreover, it presents a great performance under conditions with intensive wind speed variations. The studied Wind Energy Conversion System (WECS) consists of a Permanent Magnet Synchronous Generator (PMSG) connected to the dc link through a Pulse-Width Modulated (PWM) rectifier. The proposed algorithm and the conventional methods are applied to this WECS and their performances are compared using the simulation results. These results approve the satisfactory performance of the proposed algorithm and its notable advantages over the conventional methods.
V. Abbasi, S. Hemmati, M. Moradi,
Volume 15, Issue 1 (March 2019)
Abstract
Stress grading (SG) layer in cable terminations limits the critical electric field and properties of SG materials are important issues which have to be considered during manufacturing and selecting procedure. In this paper, two different types of (SG) materials are analyzed by both theory and test. According to the applied theory, important parameters as: electrical resistivity, breakdown voltage and thermal conductivity are determined by experiments. Experimental steps are defined in the paper with which theory and experiments are matched together to complete the investigation. The paper discusses electro-thermal breakdown theory and quality of two different SG layers based on the test results. The theory and experimental procedure can be used for prediction of breakdown voltage in cable terminations. The employed method is useful for qualifying the cable terminations by users who want to buy and install heat shrink cable terminations.
R. Rezavandi, D. A. Khaburi, M. Siami, M. Khosravi, S. Heshmatian,
Volume 17, Issue 2 (June 2021)
Abstract
Recently, Brushless Cascaded Doubly Fed Induction Generator (BCDFIG) has been considered as an attractive choice for grid-connected applications due to its high controllability and reliability. In this paper, a Finite Control Set Model Predictive Control (FCS-MPC) method with active and reactive power control capability in grid-connected mode is proposed for controlling the BCDFIG in a way that notable improvement of the dynamic response, ripple reduction of the active and reactive power waveforms and also better THD performance are achieved compared to the traditional approaches such as Vector Control (VC) method. For this purpose, the required mathematical equations are obtained and presented in detail. In order to validate the proposed method performance, a 1–MW grid-connected BCDFIG is simulated in MATLAB/Simulink environment.
B. Mamipour Matanag, N. Rostami, S. Tohidi,
Volume 17, Issue 2 (June 2021)
Abstract
This paper proposes a new method for direct control of active power and stator flux of permanent magnet synchronous generator (PMSG) used in the wind power generation system. Active power and stator flux are controlled by the proposed discrete time algorithm. Despite the commonly used vector control methods, there is no need for inner current control loops. To decrease the errors between reference and measured values of active power and stator flux, the space vector modulation (SVM) is used, which results in a constant switching frequency. Compared to vector control, the proposed direct control method has advantages such as higher dynamic response due to elimination of inner current control loops and no need to coordinate system transformation blocks as well as the PI controllers and their adjustment. Moreover, permanent magnet flux vector and several machine parameters such as stator inductances are not required which can improve the robustness of the control system. The proposed method can be used in both types of surface-mounted and interior PMSGs. The effectiveness of the proposed method in comparison to the vector control method with optimized PI coefficients by the particle swarm algorithm is evaluated. Simulation results performed in MATLAB/Simulink software show that higher dynamic response with lower active power and the stator flux ripple are achieved with the proposed method.
G. S. Kumar, G. Mamatha,
Volume 19, Issue 1 (March 2023)
Abstract
In today's technological environment, designing the Static Random Access Memory (SRAM) is most vital and critical memory devices. In this manuscript, two kinds of 5TSRAM are designed using different CNTFET such as Dual-ChiralityGate all around (GAA) CNTFET and Ballistic wrap gate CNTFET based 5T SRAM cell designs for enhancing the read/write assist process. Here, the proposed Dual-ChiralityGAA-CNTFET based 5T-SRAM has two cross-coupled inverters using one access transistor that is connected to the bit line (BL) and word line (WL) through minimum supply voltage. Instead of cross-coupled inverter circuit, the BWG-CNTFET based 5T-SRAM cell is intended for achieving less power and improved read/write assist process. Also, one transistor is executed as low-threshold (LVT) device in the proposed BWG-CNTFET based 5T-SRAM. Thus, proposed two kinds of 5T SRAM cells increases the read/write assist operation and reduce the leakage current/ power. The simulation of the proposed two kinds of 5T SRAM cell is done by HSPICE simulation tool and the performance metrics are calculated. Therefore, the proposed Dual-ChiralityGAA-CNTFET based 5T-SRAM cell design has attained 11.31%, 51.47% lower read delay, 44.44%, 26.33% lower write delay, 36.12%, 45.28% lower read power, 34.5% , 22.41% lower write power, 37.4%, 15.3% higher read SNM and 35.8%, 12.09% higher write SNM than Double gate carbon nanotube field effect transistors (DG CNTFET) and state-of-art method respectively. Similarly, the proposed BWG-CNTFET 5T SRAM cell design has attained 45.53%, 38.77% lower write delay, 56.67%, 45.64% lower read delay, 58.4%, 56.75% lower read power, 49.66%, 28.56% lower write power, 35.32%, 12.7% higher read SNM and 45.8%, 15.6% higher write SNM than Reduced Power with Enhanced Speed (RPES) approach and state-of-art method respectively.
Arizadayana Zahalan, Samila Mat Zali, Ernie Che Mid, Noor Fazliana Fadzail,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
Photovoltaic (PV) systems are vital in the global renewable energy landscape because of their capability to harness solar energy efficiently. Ensuring the continuous and efficient operation of PV systems is crucial in maximizing their energy contribution. However, these systems' reliability and safety remain critical because they are prone to various faults, mainly when operating in harsh environmental conditions. This study addresses these issues by exploring fault detection and classification in PV arrays using neural network (NN) -based techniques. A PV array model, consisting of 3x6 PV modules, was simulated using MATLAB Simulink to replicate real-world conditions and analyse various fault scenarios. An open circuit, a short circuit, and a degrading fault are the three types of faults considered in this study. The NN was trained on a dataset generated from the MATLAB Simulink model, encompassing normal operating and fault conditions. This training enables the network to learn the distinctive patterns associated with each fault type, enhancing its detection accuracy and classification capabilities. Simulation results demonstrate that the NN-based approach effectively identifies and classifies the three types of faults.
Yanawati Yahya, Nor Shafiqin Shariffuddin, Muhammad Khairul Hisyam Jarail, Dina Maizana, Phd Ibrahim Alhamrouni, Mohd Khairil Rahmat,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
Induction motors are highly favored in industrial applications for their ease of operation, compactness, lightweight, efficiency, low maintenance, and cost-effectiveness. They are widely used in conveyors, compressors, crushers, drills, fans, escalators, refrigerators, and electric vehicles. In Malaysia, industrial motors account for about 48% of energy consumption. This research introduces an improved rotor design with optimized rotor bars. Using MotorSolve (IM) software and theoretical calculations, the study found that the new design boosts energy efficiency. The new rotor bar design achieved an energy efficiency of 76.92%, compared to 74% for the current design. In terms of energy efficiency, this research found that adopting high-efficiency motors in industrial applications can save a significant amount of energy. These motors can also be used in a variety of horsepower ranges. The research suggests a maintenance plan for malfunctioning motors that attempts to reduce energy consumption, motor losses, and CO2 emissions in any apparatus. These results offer valuable insights for policymakers to refine energy policies for induction motors. In the future, real-time estimation of the motor's actual operating loss will be required to properly predict the trend in motor efficiency loss under various failure scenarios, which is consistent with the research goal of reducing energy losses in induction motors.
Noor Fazliana Fadzail, Samila Mat Zali, Ernie Che Mid,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
The activation function has gained popularity in the research community since it is the most crucial component of the artificial neural network (ANN) algorithm. However, the existing activation function is unable to accurately capture the value of several parameters that are affected by the fault, especially in wind turbines (WT). Therefore, a new activation function is suggested in this paper, which is called the double sigmoid activation function to capture the value of certain parameters that are affected by the fault. The fault detection in WT with a doubly fed induction generator (DFIG) is the basis for the ANN algorithm model that is presented in this study. The ANN model was developed in different activation functions, namely linear and double sigmoid activation functions to evaluate the effectiveness of the proposed activation function. The findings indicate that the model with a double sigmoid activation function has greater accuracy than the model with a linear activation function. Moreover, the double sigmoid activation function provides an accuracy of more than 82% in the ANN algorithm. In conclusion, the simulated response demonstrates that the proposed double sigmoid activation function in the ANN model can effectively be applied in fault detection for DFIG based WT model.
Murni Nabila Mohd Zawawi, Zainuddin Mat Isa, Baharuddin Ismail, Mohd Hafiz Arshad, Ernie Che Mid, Md Hairul Nizam Talib, Muhammad Fitra Zambak,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
This study introduces a pioneering method to enhance the efficiency and effectiveness of three-phase five-level reduced switch cascaded H-bridge multilevel inverters (CHB MLI) by employing the Henry Gas Solubility Optimization (HGSO) algorithm. Targeting the selective harmonic elimination (SHE) technique, the research emphasizes the optimization of switching angles to significantly reduce total harmonic distortion (THD) and align the fundamental output voltage closely with the reference voltage. Central to this exploration are three distinct objective functions (OFs), meticulously designed to assess the HGSO algorithm’s performance across various modulation indices. Simulation results, facilitated by PSIM software, illustrate the impactful role these objective functions play in the optimization process. OF1 demonstrated a superior ability in generating low OF values and maintaining a consistent match between reference and fundamental voltages across the modulation index spectrum. Regarding the reduction of THD, it is crucial to emphasize that all OFs can identify the most effective switching angle to minimize THD and eliminate the fifth harmonic to a level below 0.1%. The findings highlight the potential of HGSO in solving complex optimization challenges within power electronics, offering a novel pathway for advancing modulation strategies in CHB MLIs and contributing to the development of more efficient, reliable, and compact power conversion systems.
Nurul Husna Abd Wahab, Mohd Hafizuddin Mat, Norezmi Md Jamal, Nur Hidayah Ramli,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
In islanded microgrids, circulating currents among parallel inverters pose significant challenges to system stability and efficient power distribution. Traditional droop control methods often struggle to manage these currents effectively, leading to inefficiencies and potential system damage. This study introduces an advanced fuzzy-robust droop control strategy that integrates fuzzy logic with robust droop control to address these challenges. By incorporating fuzzy logic, the proposed strategy enhances the adaptability of droop control to varying system conditions, improving the management of circulating currents and ensuring more accurate power sharing among inverters. Comprehensive mathematical modeling and extensive simulation analyses validate the performance of this control strategy. The results show that the fuzzy-robust droop control method significantly outperforms conventional approaches, achieving up to a 70% reduction in circulating currents. This improvement leads to a substantial reduction in power losses and enhances the dynamic response under varying load conditions. Additionally, the strategy improves voltage and frequency regulation, contributing to the overall stability and reliability of the microgrid. The findings provide a robust solution to the longstanding issue of circulating currents, optimizing microgrid operations, and paving the way for more efficient and resilient distributed energy systems. The advanced control strategy presented in this study not only addresses critical challenges but also demonstrates the potential for innovative methodologies to meet the growing demands of future energy infrastructures, where reliability and efficiency are essential.
Huang Yan, Hadi Nabipour Afrouzi, Chin-Leong Wooi , Hieng Tiong Su, Ismat Hijazin,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
In order to solve the difficulty of digital signal calibration of electric power equipment, such as low precision, inability to test the full range, and complicated configuration, and further promote the development of power system, a proposed time measurement calibration device is designed, and its performance is verified in this paper. This paper points out the main drawbacks of the existing calibration system, carries on the design innovation of the key technologies based on FPGA (Field Programmable Gate Array), puts forward the optimization method of the software and hardware, and verifies the accuracy of the input and output signal by experiments. The accuracy of input and output SV, GOOSE, and contact signal of the proposed calibration device in this paper can be better than 10μs, which is a meaningful improvement in accuracy and efficiency for time measurement calibration.
Nurul Hidayah Rodzuan, Ili Najaa Aimi Mohd Nordin, Ahmad ‘athif Mohd Faudzi, Noraishikin Zulkarnain, Muhammad Rusydi Muhammad Razif, Nik Normunira Mat Hassan, Muhamad Hazwan Abdul Hafidz,
Volume 21, Issue 2 (Special Issue on the 1st International Conference on ELECRiS 2024 Malaysia - June 2025)
Abstract
Rehabilitation devices like assistive gloves require bending-type soft actuators for controlled, repetitive finger movements essential for therapy. However, non-segmented actuators often struggle to replicate natural finger articulation, which can cause discomfort and reduce patient compliance. This paper presents the design and assembly of a segmented bending pneumatic soft actuator to achieve index finger flexion, aiming to improve comfort and support natural finger movement at low pressure. The actuator is integrated into a glove with a flexible bend sensor to measure the flexion angle of the metacarpophalangeal joint. Ecoflex 0-50 A-B silicone rubber is used in the fabrication, with air bubbles removed to ensure consistent actuator performance. The study investigates the actuator's performance and the sensor's ability to accurately measure joint flexion. The results, presented through detailed graphs, analyze the actuator’s flexibility, bending, and elongation under different pressure scenarios, offering insights into its effectiveness in improving patient comfort, joint articulation, and rehabilitation outcomes.
Nasibeh Heshmati Moulaei, Eisa Zarepour, Seyed Ali Seyedalian, Alireza Sinaee Oskouie,
Volume 21, Issue 3 (September 2025)
Abstract
As the demand for continuous online remote monitoring of patients grows, the energy consumption of wearable home-care monitoring systems (WHMSs) requires careful evaluation. Selecting the right communication protocol therefore is crucial to minimize energy usage and extend device lifecycles. Recent versions of Bluetooth Smart (IEEE 802.15.1 are promising for WHMSs, offering low energy consumption and extended coverage range. However, their energy consumption in WHMSs remains underexplored. This paper investigates the energy consumption and maximum coverage range of Bluetooth V4.2, V5/1MB and V5/2MB in various home-care environments. We propose a software and hardware-based energy monitoring framework to practically measure the energy consumption of the protocols, conducting extensive experiments in typical home scenarios with obstacles like kitchen cabinets, brick walls, and the human body. Our results show similar power consumption for BLE v4.2 and BLE v5 modules, but the BLE v5/2MB has lower energy usage than BLE v5/1MB due to faster transmission. Additionally, obstacles significantly impact energy consumption and range, with BLE v5/1MB achieving a maximum range of 108m in line-of-sight conditions, which drops to 45m and 29m with brick walls and human bodies, respectively. Finally, the BLE v5/2MB effective range in all experimental scenarios is about 80% of BLE v5/1MB.
