Research Interests:
Research Interests:
Research Interests:
Low Voltage Direct Current (LVDC) Photovoltaic (PV) systems are considered suitable solutions for increasing the capacity of existing LV networks. They provide a good power quality, renewable energy source compatibility, and simple... more
Low Voltage Direct Current (LVDC) Photovoltaic (PV) systems are considered suitable solutions for increasing the capacity of existing LV networks. They provide a good power quality, renewable energy source compatibility, and simple integration with batteries. This paper compares the proposed LVDC supply concept with existing traditional PV systems regarding energy efficiency. The proposed LVDC Photovoltaic System was realized. The results obtained from this study revealed that using the LVDC system supply concept, instead of Low Voltage Alternative Current (LVAC) ones, is very interesting if the PV-generated electricity is used locally during day hours. To achieve a high PV system efficiency, the PV power installed in the houses should be accurately sized regarding the consumed energy. The shorted path taken by the PV-generated power to feed load during daytime is the main advantage of the proposed LVDC architecture.
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Tracking the Maximum Power Point (MPP) of a photovoltaic (PV) array is usually an essential part of a PV system. The problem addressed by Maximum Power Point Tracking (MPPT) techniques is to find the voltage VMPP or current IMPP at which... more
Tracking the Maximum Power Point (MPP) of a photovoltaic (PV) array is usually an essential part of a PV system. The problem addressed by Maximum Power Point Tracking (MPPT) techniques is to find the voltage VMPP or current IMPP at which a PV array should operate to generate the maximum power output PMPP under a given temperature and irradiance. A Novel analog integrated maximum power point tracking (MPPT) chip is presented in this paper. The main task is to design and implement an integrated circuit (IC) in CMOS technology to control the MPP in PV panel. The MPPT controller can be made small enough to be integrated into the junction box, which is practical and cost effective for MPPT topology. For the design, two main steps are necessary. First, the front end step, which consists of the validation of the design by Cadence simulations. These steps are crucial since they determine the performance capability of the design. The second phase is the back end step, which consists of the design of the layout of the circuit and all necessary verifications.
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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... 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 others 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 employment of the LVDC chain supply concept is very interesting and the use of DC loads as an alternative to AC loads, when a PV power is generated locally, is more efficient. The installed PV power source in the building should be well sized regarding to the consumed power in order to register a high system RSE.
Research Interests:
Low Voltage Direct Current (LVDC) Photovoltaic (PV) systems are considered suitable solutions for increasing the capacity of existing LV networks. They provide a good power quality, renewable energy source compatibility, and simple... more
Low Voltage Direct Current (LVDC) Photovoltaic (PV) systems are considered suitable solutions for increasing the capacity of existing LV networks. They provide a good power quality, renewable energy source compatibility, and simple integration with batteries. This paper compares the proposed LVDC supply concept with existing traditional PV systems regarding energy efficiency. The proposed LVDC Photovoltaic System was realized. The results obtained from this study revealed that using the LVDC system supply concept, instead of Low Voltage Alternative Current (LVAC) ones, is very interesting if the PV-generated electricity is used locally during day hours. To achieve a high PV system efficiency, the PV power installed in the houses should be accurately sized regarding the consumed energy. The shorted path taken by the PV-generated power to feed load during daytime is the main advantage of the proposed LVDC architecture.
Research Interests:
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... 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 others 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 employment of the LVDC chain supply concept is very interesting and the use of DC loads as an alternative to AC loads, when a PV power is generated locally, is more efficient. The installed PV power source in the building should be well sized regarding to the consumed power in order to register a
Research Interests:
Research Interests:
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... 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 ProteusISIS. A good efficiency of the analog technique (more than 98%) was registered. The variation of irradiations was introduced in order to study the robustness of the proposed analog MPPT technique. A prototype of an off-grid PV system using the proposed analog technique is realized with discrete devices and it's feasibility is proved. In future, a new analog circuit can be realized in an Integrated Circuit to replace classical techniques based on μprocessor solutions used in PV systems.
A new approach to the optimal design of power inverters for on-grid photovoltaic systems that uses genetic algorithms (GA) is provided in this article. The nonlinear average model is adopted to model the conversion stage in order to... more
A new approach to the optimal design of power inverters for on-grid photovoltaic systems that uses genetic algorithms (GA) is provided in this article. The nonlinear average model is adopted to model the conversion stage in order to accurately evaluate and quickly estimate the power losses of the power devices. The hysteresis current control that guarantees a quasi-sinusoidal output current is applied to generate the inverter control signals. The design of the solar inverter must meet three contradictory objectives that need to be optimized at the same time. In fact, the aim is to maximize the efficiency of the converter while minimizing its size and price under electrical constraints. The problem variables are the output current ripple and the passive and active components available on the market (IGBTs/MOSFETs, Diodes, Inductors). NSGA-II (Elitist Nondominated Sorting Genetic Algorithm) is appropriate in the case where discrete design variables are used to search for optimal Paret...
Research Interests:
Research Interests:
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... 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.
Research Interests:
Design an efficient high frequency transformer or inductor is based on accurate core loss and winding loss models. Steinmetz and Dowell's equations are the most common methods used for this purpose. The selection of the optimum... more
Design an efficient high frequency transformer or inductor is based on accurate core loss and winding loss models. Steinmetz and Dowell's equations are the most common methods used for this purpose. The selection of the optimum magnetic core depends on both: the core and the winding losses. The core geometry coefficient is a popular method which Steinmetz equation, valid for sinusoidal excitation, and the DC copper loss formula are coupled together to determine the suitable magnetic core. However, in switching power supplies, excitation waveforms are non-sinusoidal. This implies that the frequency and the duty cycle can have a great effect on the core and copper losses. As a result, the magnetic core could be undersized which leads to decrease the efficiency. The main contribution of this paper is to develop a simple and compact formula to select the optimum magnetic core. This formula includes the effects of the frequency and the duty cycle on the magnetic and winding losses.
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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... 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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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... 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.
Research Interests:
Research Interests:
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... 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...
Research Interests:
Research Interests:
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... 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.
Research Interests:
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... 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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Research Interests: Engineering and IEEE
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... 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.