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PublicationA five-level inverter using SEPIC converter for motor drive application(AIP Publishing Ltd., 2023)The research in inverter is one of the fast-evolving technology in the present era and many researchers start to replace the conventional transformer with different types of circuits. A major problem with the conventional transformers resulting in entire system in expensive range and voluminous. This paper will demonstrate a new technique to replace the conventional transformer concept by using dual DC/DC SEPIC Converter and modified H-bridge inverter to form a five-level inverter with multirange voltage selection which depending on the duty-cycle employed for SEPIC converter. The input DC voltage of the proposed inverter can be stepped-down or stepped-up the five-level output voltage waveform which make it suitable to drive the AC motor drive. A simulation using PowerSim with various duty-cycle values, are used to evaluate the suggested inverter.
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PublicationAccelerated thermal aging of Kraft papers impregnated with dielectric liquids(Institute of Advanced Engineering and Science (IAES), 2023)Accelerated thermal aging was conducted on Kraft papers impregnated with mineral insulating oil (MO) and palm insulating oil (PO), and the effect of aging time on the oils and Kraft papers was observed. Each sample consisted of insulating oil, dried Kraft paper, and weighed metal catalysts (copper, iron, zinc, and aluminum) in a bottle. Prior to aging, the bottles were left for 24 h at room temperature for impregnation to take place. The thermal aging experiments were carried out at 130 °C for 250, 500, and 750 h. The properties of the MO and PO (moisture content, acidity, and ultraviolet-visible absorption spectra) and the properties of the Kraft papers (tensile strength and colour) were determined. Results showed that the aged PO had higher moisture content compared with the aged MO. However, the Kraft papers impregnated with PO had better tensile strength after 750 h of aging, which may be attributed to the affinity of PO to moisture. This slows down the hydrolytic degradation mechanism. In terms of colour, the Kraft papers were darker than their original colour as the tensile strength decreased. To conclude, the Kraft paper impregnated with PO had higher tensile strength compared with those impregnated with MO.
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PublicationElectricity generation through microbial fuel cells utilizing leftover rice as food waste(Semarak Ilmu Publishing, 2023)Organic food waste management has been a major issue for the environment, as it poses a significant threat to human health and the ecosystem. Converting this waste into a valuable resource is crucial for sustainable development. In this project, we aim to develop a microbial fuel cell (MFC) using leftover rice as a substrate, which can generate electricity through the electrochemical reactions of microorganisms. The main objectives of this study are to investigate the performance of MFCs under two different conditions: with and without a mediator and catalyst. The experimental results showed that both designs of MFCs achieved optimized outputs, with a minimum of 5V voltage output. This demonstrates the potential of MFCs as a promising alternative renewable energy source. MFCs can be utilized as a sustainable energy source, particularly for rural areas, where access to electricity is limited. Furthermore, large-scale operation of MFCs can significantly reduce food waste, which has a significant impact on health and the environment. By converting food waste into electricity, this technology can help mitigate the negative effects of waste accumulation and contribute to the transition towards a circular economy.
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PublicationFlexible sector detector-based mismatch supply voltage in direct torque control doubly fed induction machine: an experimental validation(Elsevier, 2023)Direct Torque Control (DTC) of Induction Motors (IMs) is popular in motor drive applications because of its robust and simple control structure. The IM winding can be controlled on both sides using dual inverter technique which more effective for Electric Vehicle (EV) with a greater number of voltage vectors. However, the battery performance of the dual inverter will deteriorate unevenly on both sides, resulting in fluctuating voltages for the EV system. This will lead to the generation of distorted stator currents and a significant droop in the stator flux, which in turn can increase the total harmonic distortion (THD) in the system. Additionally, the performance of torque may not be able to regulate effectively. This paper examines the effect of unstable voltage on voltage vector mapping performance with tilted angles and proposes new sector definitions based on voltage ratio conditions. Moreover, the proposed sector for each predefined voltage ratio is tested under three-speed conditions. The proposed technique effectiveness is validated through hardware experiments using a dSPACE 1104 controller and retuning the stator current for proper waveform. This approach improves the stator current waveform, improves stator flux droop, enhances torque regulation and minimizes the THD in the DTC system.
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PublicationControl strategies of power electronic converter for grid-tied variable low-speed wind turbine(AIP Publishing Ltd., 2023)With the increased penetration of wind energy on modern power systems, Wind Energy Conversion Systems (WECS) are required to participate actively in capturing the maximum wind energy and operating electric networks through a suitable control strategy. This paper provides the design and implementation of control strategies for Fully Controlled Power Electronic Converter (FCPEC) associated with a Variable Low-speed Wind Turbine (VLSWT) system. The considered system consists of a Wind Turbine (WT) and Permanent Magnet Synchronous Generator (PMSG) that are linked to the grid via an FCPEC. The control schemes of the FCPEC include a Maximum Power Point Tracking (MPPT) algorithm, a Machine Side Converter (MSC) control, and a Grid Side Inverter (GSI) control. To validate the effectiveness of the implemented control strategies, the considered system was modelled and simulated using MATLAB/Simulink under Malaysia wind speed profiles (2 m/s - 6 m/s). The simulation results proved that the MPPT algorithm and MSC control have successfully forced WT to operate at the optimal power coefficient of 0.44 further improved the maximum power available from the wind system that can be obtained. Besides, the results showed the capability of the GSI controller in improving the system performance in both steady-state and disturbance operating conditions. The dc-link voltage regulation and power integration to grid, with a unity power factor regardless of wind speed variation, were successfully accomplished.