Papers by Abdulrahman al-Ahdal
Advances in Power Electronics, 2017
A new analog technique is proposed in order to track the maximum power point (MPP) of PV panels. ... more A new analog technique is proposed in order to track the maximum power point (MPP) of PV panels. The proposed technique uses the well-known simple functions of electronic circuits. The proposed technique is validated by applying it to boost based off grid PV system. The simulation of the PV system was done on the circuit oriented simulator Proteus-ISIS. A good efficiency of the analog technique (more than 98%) was registered. The variation of irradiation was introduced in order to study the robustness of the proposed analog MPPT technique.
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2012 IEEE Biomedical Circuits and Systems Conference (BioCAS), 2012
Ion sensitive field effect transistors (ISFETs) built in standard CMOS technology are effectively... more Ion sensitive field effect transistors (ISFETs) built in standard CMOS technology are effectively floating gate devices. They suffer from random trapped charges that alter their threshold voltage (Vt). This paper describes one way to program an ISFET's floating gate charges in order to bring its Vt to a desirable value using bidirectional electron tunnelling. Two inputs are capacitively coupled to the ISFET's floating gate via matched capacitors. They are used to indirectly tunnel opposite currents across their oxide isolation to the ISFET's floating gate in a controlled way. The floating gate charges are programmed using a balanced combination of these two tunnelling currents. Measured experimental results demonstrated programmability and removal of positive and negative trapped charges.
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A device and method for threshold voltage programming of an Ion Sensitive Field Effect Transistor... more A device and method for threshold voltage programming of an Ion Sensitive Field Effect Transistor (ISFET) is of particular use in matching ISFETs in an array, which may be used in biological reaction monitoring. A circuit comprises an Ion Sensitive Field Effect Transistor (ISFET) having a floating gate and two tunnelling inputs Vt+ and Vt- coupled by capacitors Ct+ and Ct- to the floating gate for bidirectional electron tunneling to program a charge on the floating gate. The field programmable circuit enables calibration of ISFETs in an array to bring electrical parameters to a desirable point.
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International Journal of Chemical Engineering and Applications, 2015
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Electronics Letters, 2011
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Electronics Letters, 2012
Ion sensitive field effect transistors (ISFETs) are pH sensors that have generally been used in t... more Ion sensitive field effect transistors (ISFETs) are pH sensors that have generally been used in the analogue domain. It is possible to use them in the digital domain for chemical thresholding applications. To facilitate small pH change detection where a simple switch suffers from ripple and distorted output, a chemical switch with input noise immunity is needed. Reported are first measurements of an ISFET-based chemical Schmitt trigger. It provides a more stable output with better noise immunity. It can be used in applications where the digital detection of small pH changes is required.
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EPJ Photovoltaics
The tracking of the maximum power point (MPP) of a photovoltaic (PV) solar panel is an important ... more The tracking of the maximum power point (MPP) of a photovoltaic (PV) solar panel is an important part of a PV generation chain. In order to track maximum power from the solar arrays, it is necessary to control the output impedance of the PV panel, so that the circuit can be operated at its Maximum Power Point (MPP), despite the unavoidable changes in the climate conditions such as temperature and Irradiance. A new MPPT analog technique to track the Maximum Power Point (MPP) of PV arrays is proposed. This new technique uses simple and classical functions of electronic circuits. An Off-Grid PV system was considered to apply and validate the proposed new technique. The entire circuit was implemented in circuit-oriented simulator Proteus-ISIS. We present the results associated with the design, the realization, and the experimentation of a PV system equipped with a new analog MPPT command. The obtained results have shown good efficiency of analog technique (more than 98.5%). The second p...
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Ion sensitive field effect transistors (ISFETs) have long been used as analogue chemical sensors ... more Ion sensitive field effect transistors (ISFETs) have long been used as analogue chemical sensors particularly for biomedical applications. However, there are some applications where a “yes“/“no“ type answer regarding pH change is sufficient. For example, in DNA sequencing the question is whether a chain extension reaction took place or not. Detecting this at the sensing point reduces the sensing process to pH change threshold detection. It eliminates the need for analogue to digital conversion and facilitates an all digital sensory system. This thesis presents Novel Floating Gate ISFET based Chemical Inverters that were created with semiconductor based biomedical applications in mind. It starts by allowing two ISFETs to share the same ion sensing membrane and a common floating gate. Arranging them in a simple FG inverter configuration, their switching may be triggered by either the reference voltage or chemical pH change. In order to enhance its input noise immunity, a chemical Schm...
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The Low Voltage Direct Current (LVDC) system concept has been growing in the recent times due to ... more The Low Voltage Direct Current (LVDC) system concept has been growing in the recent times due to its characteristics and advantages like renewable energy source compatibility, more straightforward integration with storage utilities through power electronic converters, and distributed loads. This paper presents the energy efficiency performances of a proposed LVDC supply concept and other classical PV chains architectures. A PV source was considered in the studied nanogrids. The notion of relative saved energy (RSE) was introduced to compare the studied PV systems energy performances. The obtained results revealed that the use of the proposed LVDC chain supply concept increases the nanogrid efficiency. The installed PV power source in the building should be well sized regarding the consumed power in order to register a high system RSE. The efficiency of the new LVDC architecture is 10% higher than the conventional LVDC one.
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Videos are full of dynamic changes along both the spatial and temporal dimensions. Large, jerky s... more Videos are full of dynamic changes along both the spatial and temporal dimensions. Large, jerky short-term motions make it difficult to extract significant changes from videos such as subtle color changes and long-term motions occurring in time-lapse sequences. In this paper, we introduce two singular value decomposition (SVD)-based video decomposition schemes to clearly reveal such changes. The first scheme involves enhancing the visual characteristics of small subtle color changes in the presence of a wide variety of motion patterns by magnifying their pixel intensities. The second scheme removes short-term motions that visually distract attention from the underlying content of video sequences such as time-lapse videos, snowing scene, and maritime surveillance. Both schemes involve the decomposition of videos into spatiotemporal slices in which each slice is further decomposed into several singular components. The low-rank components that primarily represent background and color i...
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International Journal of Energy Research
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2016 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC), 2016
In this paper, a simplified analytical frequency model of conducted EMI generated by a DC/DC conv... more In this paper, a simplified analytical frequency model of conducted EMI generated by a DC/DC converter is proposed. The methodology is based on the relationship between the noise source and the propagation path. The effect of the parasitic elements was taken into account in the noise sources waveforms. The proposed method was verified by comparing the improved models results with the time domain simulation results using Saber® simulation tool.
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2016 7th International Renewable Energy Congress (IREC), 2016
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2016 7th International Renewable Energy Congress (IREC), 2016
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2016 7th International Renewable Energy Congress (IREC), 2016
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Sensors and Actuators B: Chemical, 2012
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2013 Saudi International Electronics, Communications and Photonics Conference, 2013
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2012 16th IEEE Mediterranean Electrotechnical Conference, 2012
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IEEE Sensors Journal, 2000
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Papers by Abdulrahman al-Ahdal