In the present work, wireless sensor network and smart real-time controlling and monitoring system are integrated for
efficient energy management of standalone photovoltaic system. The proposed system has two main components namely
the monitoring and controlling system and the wireless communication system. LabView software has been used in the
implementation of the monitoring and controlling system. On the other hand, ZigBee wireless modules have been used to
implement the wireless system. The main functions of monitoring and controlling unit is to efficiently control the energy
consumption form the photovoltaic system based on accurate determination of the periods of times at which the loads are
required to be operated. The wireless communication system send the data from the monitoring and controlling unit to
the loads at which desired switching operations are performed. The wireless communication system also continuously
feeds the monitoring and controlling unit with updated input data from the sensors and from the photovoltaic module
send to calculate and record the generated, the consumed, and the stored energy to apply load switching saving schemes
if necessary. It has to be mentioned that our proposed system is a low cost and low power system because and it is
flexible to be upgraded to fulfill additional users’ requirements.
KEYWORDS: Solar energy, Sensors, Computer programming, Solar cells, Photovoltaics, Control systems, Transceivers, Computing systems, Environmental monitoring, Data acquisition
In the present work, a computer based smart integrated energy monitoring and management system for standalone photovoltaic systems is designed and implemented. Monitoring, controlling, and recording features are fully obtained in the present system using an efficient programming environment. All required data are monitored as real-time data therefore the system status is continuously evaluated and decisions are made to take immediate actions. The energy consumption of different appliances are automatically controlled and optimized using a hierarchical self adaptive algorithm based on input data and real-time information provided by the system sensors. The proposed system is successfully implemented for photovoltaic modules under realistic operating conditions.
In the present work, a computer based photovoltaic sun tracker module is designed and implemented. Monitoring,
controlling, and recording features are fully obtained in the present system using an efficient programming environment
Design equations which are implemented allow the usage of the system anywhere anytime without extra hardware
tracking circuits. A carefully design hardware motor deriving circuit is designed and implemented to simplify the
controlling program without scarifying the required accuracy. The system generates the motors' controlling signals to
allocate the photovoltaic module to receive the maximize amount of the solar energy on its surface from sunrise to
sunset. The proposed system is successfully implemented for photovoltaic modules under realistic operating conditions.
KEYWORDS: Magnetic sensors, Field effect transistors, Magnetism, Sensors, Magnetic semiconductors, Semiconductors, Solid modeling, Systems modeling, Electrons, Instrument modeling
Characteristics of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) magnetic sensors have been
investigated using a three-dimensional physical simulator which accurately couples the magnetic field equation and the
carrier transport equations. The effects of the device geometric parameters, the bias conditions, and the magnetic field on
the relative sensitivity of a split drain magnetic sensors are accurately determined. The MOSFET magnetic sensor
capability is further enhanced by suggesting an integrated smart structure which is able to fully detect the magnetic field
variations in two-directions. The current deflection and relative sensitivity for the suggested magnetic sensor under
different operating conditions are finally investigated with the present efficient physical simulator.
A precise two-dimensional MOS magnetic sensor is suggested and its performance is investigated. The dependence of
sensor sensitivity on the device geometric parameters and on the biasing conditions is accurately determined by a twodimensional
physical simulator which self-consistently solves the magnetic field equations and the carrier transport
equations. From the simulation results, a modified equivalent circuit model for MOS magnetic sensor is proposed and
included in SPICE model to fully analyze the operation of suggested magnetic field sensor.
Analytical expressions for the PM noise in FET oscillators are derived in terms of the FET equivalent circuit elements
and the passive circuitry. Efficient methods to reduce the PM noise in fundamental and in harmonic mode are suggested
and implements. The effects of the different FET equivalent circuit parameters on large-signal, small-signal, and noise
behaviour of FET oscillators are thoroughly investigated. Finally, the effects of harmonic signal on both fundamental
and harmonic output noise are determined.
In the present work, a rigorous two-dimensional physical simulator is developed to characterize the operation and to
optimize the structure of a highly sensitive linear 2D MOSFET magnetic sensor. The magnetic field equation and the
carrier transport equations are efficiently coupled and accurately solved to determine the effects of external applied
magnetic field on the electrical characteristics of the MOSFET based sensor. The accuracy of the present simulator is
tested for different device and circuit parameters to allow the use of it as an efficient CAD tool to fully characterize smart
two-directions MOSFET magnetic sensor.
The noise performance of sub-quarter micrometer gate length FETs is determined by using physical simulators. The hydrodynamic transport model equations are linearized and efficiently solved in two dimensions to determine the small-signal parameters and the minimum noise figure up to frequencies near the device cut-off frequency. For higher frequencies, the noise performance is obtained by using a 2D Monte Carlo code which fully takes into account the non-stationary transport properties and quantization effects. The relation between the terminal noise currents and the internally generated noise at the different device regions are determined. Different device stuctures are simulated and the obtained results are compared with experimental data.
Electronic states inside heterostructure devices are accurately calculated by using an efficient scheme. The scheme is based on self-consistent solution of Schroedinger’s equation (using variational technique) together with Poisson’s equation. The model is applied to in one dimensional heterostructure FET to determine its characteristics. The model is then extended in two-dimensions to determine the electronic states in low-dimensional heterostructure devices and quantum wires. The advantages and limitations of the present scheme are finally discussed.
The influence of alloy composition on the noise behavior of heterostructure semiconductor devices is investigated by using a rigorous two-dimensional physical simulator. The model takes into account non-stationary transport properties and quantization effects to allow a better understanding of the carrier transport properties inside the heterostructure devices and consequently to explain the noise performance of these devices by making use of the microscopic nature of the model. As an example, the model is applied to study the effects of alloy composition and the resulting band discontinuity on the 2DEG properties and on the noise performance of Hetero-FETs at millimeter-wave frequencies, and to extract the optimum alloy composition which leads to the minimum noise figure in different frequency ranges.
A new graded band gap channel MOSFET is suggested to make use of the improved electrical properties of SiGe over Si at high frequencies of operation. The device performance is analyze by using an analytical model and the obtained results are compared with those of conventional Si and non- uniform doped channel MOSFETs. Finally, the noise behavior of the new MOSFET is investigated to show its superior performance over conventional Si MOSFETs at GHZ frequencies of operation.
A nonlinear multimode frequency-domain analysis of the gyrotron is used to study the effect of excentricity of the electron beam on its performance. The guiding center of the electron beam which is usually at the center of the cavity is now shifted by a distance (Delta) c. Variations in the gyrotron output power, efficiency, and oscillation frequency pulling because of the electron beam excentricity have been calculated for a simple cavity gyrotron with oscillation frequency of 35 GHz. This paper also introduces the ability of varying the electron beam radius to limit the variations due to the electron beam excentricity.
Our frequency-domain analysis which we have used to study the effect of the load reflections in a preceding paper (0.A.Abo-elnor et al, 16:-H conf. IR & MMW, Lausanne, 1991) is used now to study the effect of excentricity in electron beam and variations in its radius. Both effects cause reduction in both efficiency and output power, it is shown that considering the two effects together can equalize the output power reduction and returns the output power and efficiency to their optimum values.
In a preceding paper (Jensen, Schtinemann: "Network-Theoretical Approach to the Gyrotron Oscillator", 16th Conf. IR & MMW, Lausanne 1991) we have developed a network-theoretical approach to gyrotron oscillator analysis. As in normal microwave oscillator theory, it formulates an oscillation equation in frequency-domain in which both the device and the load admittance are generalized now to a nonlinear (and mainly frequency- insensitive) and to a linear admittance matrix, respectively. The latter describes the frequency-dependent passive circuit.
The performance of various PET oscillators with reaction, transmission, reflection, or feedback stabilizing cavity is compared with respect to loaded quality factor, output power, and AM and PM output noise. The oscillators are operating in fundamental or harmonic mode.
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