Abstract: The article presents the concept of an electromagnetic
circuit generator with permanent magnets mounted on the surface
rotor core designed for single phase work. Computation field-circuit
model was shown. The spectrum of time course of voltages in the
idle work was presented. The cross section with graphically
presentation of magnetic induction in particular parts of
electromagnetic circuits was presented. Distribution of magnetic
induction at the rated load point for each phase was shown. The time
course of voltages and currents for each phases for rated power were
displayed. An analysis of laboratory results and measurement of load
characteristics of the generator was discussed. The work deals with
three electromagnetic circuits of generators with permanent magnet
where output voltage characteristics versus rated power were
expressed.
Abstract: A circularly polarized fractal boundary microstrip
antenna is presented. The sides of a square patch along x- axis, yaxis
are replaced with Minkowski and Koch curves correspondingly.
By using the fractal curves as edges, asymmetry in the structure is
created to excite two orthogonal modes for circular polarization (CP)
operation. The indentation factors of the fractal curves are optimized
for pure CP. The simulated results of the novel polyfractal antenna
are demonstrated.
Abstract: This study focuses on the cooling of a photovoltaic
panel (PV). Indeed, the cooling improves the conversion capacity of
this one and maintains, under extreme conditions of air temperature,
the panel temperature at an appreciable level which avoids the
altering. To do this, a fan provides forced circulation of air. Because
the fan is supplied by the panel, it is necessary to determine the
optimum operating point that unites efficiency of the PV with the
consumption of the fan. For this matter, numerical simulations are
performed at varying mass flow rates of air, under two extreme air
temperatures (50°C, 25°C) and a fixed solar radiation (1000W.m2) in
a case of no wind.
Abstract: Cognitive Radio is a turning out technology that
empowers viable usage of the spectrum. Energy Detector-based
Sensing is the most broadly utilized spectrum sensing strategy.
Besides, it's a lot of generic as receivers doesn't would like any
information on the primary user's signals, channel data, of even the
sort of modulation. This paper puts forth the execution of energy
detection sensing for AM (Amplitude Modulated) signal at 710 KHz,
FM (Frequency Modulated) signal at 103.45 MHz (local station
frequency), Wi-Fi signal at 2.4 GHz and WiMAX signals at 6 GHz.
The OFDM/OFDMA based WiMAX physical layer with
convolutional channel coding is actualized utilizing USRP N210
(Universal Software Radio Peripheral) and GNU Radio based
Software Defined Radio (SDR). Test outcomes demonstrated the
BER (Bit Error Rate) augmentation with channel noise and BER
execution is dissected for different Eb/N0 (the energy per bit to noise
power spectral density ratio) values.
Abstract: This paper addresses the reduction of peak to average
power ratio (PAPR) for the OFDM in Mobile-WiMAX physical layer
(PHY) standard. In the process, the best achievable PAPR of 0 dB is
found for the OFDM spectrum using phase modulation technique
which avoids the nonlinear distortion. The performance of the
WiMAX PHY standard is handled by the software defined radio
(SDR) prototype in which GNU Radio and USRP N210 employed as
software and hardware platforms respectively. It is also found that
BER performance is shown for different coding and different
modulation schemes. To empathize wireless propagation in specific
environments, a sliding correlator wireless channel sounding system
is designed by using SDR testbed.
Abstract: The aim of this work is to present a theoretical analysis of a 2D ultrasound transducer comprised of crossed arrays of metal strips placed on both sides of thin piezoelectric layer (a). Such a structure is capable of electronic beam-steering of generated wavebeam both in elevation and azimuth. In this paper a semi-analytical model of the considered transducer is developed. It is based on generalization of the well-known BIS-expansion method. Specifically, applying the electrostatic approximation, the electric field components on the surface of the layer are expanded into fast converging series of double periodic spatial harmonics with corresponding amplitudes represented by the properly chosen Legendre polynomials. The problem is reduced to numerical solving of certain system of linear equations for unknown expansion coefficients.
Abstract: The use of permanent magnets (PM) is increasing in
permanent magnet synchronous machines (PMSM) to fulfill the
requirements of high efficiency machines in modern industry. PMSM
are widely used in industrial applications, wind power plants and the
automotive industry. Since PMSM are used in different
environmental conditions, the long-term effect of NdFeB-based
magnets at high temperatures and their corrosion behavior have to be
studied due to the irreversible loss of magnetic properties.
In this paper, the effect of magnetic properties due to corrosion
and increasing temperature in a climatic chamber has been presented.
The magnetic moment and magnetic field of the magnets were
studied experimentally.
Abstract: Standalone micro-hydrokinetic river (MHR) system is
one of the promising technologies to be used for remote rural
electrification. It simply requires the flow of water instead of
elevation or head, leading to expensive civil works. This paper
demonstrates an economic benefit offered by a standalone MHR
system when compared to the commonly used standalone systems
such as solar, wind and diesel generator (DG) at the selected study
site in Kwazulu Natal. Wind speed and solar radiation data of the
selected rural site have been taken from national aeronautics and
space administration (NASA) surface meteorology database. The
hybrid optimization model for electric renewable (HOMER) software
was used to determine the most feasible solution when using MHR,
solar, wind or DG system to supply 5 rural houses. MHR system
proved to be the best cost-effective option to consider at the study site
due to its low cost of energy (COE) and low net present cost (NPC).
Abstract: The success of renewable powered electric vehicle
charging station in isolated areas depends highly on the availability
and sustainability of renewable resources all year round at a selected
location. The main focus of this paper is to discuss the possible
charging strategies that could be implemented to find the best
possible configuration of an electric Tuk-Tuk charging station at a
given location within South Africa. The charging station is designed,
modeled and simulated to evaluate its performances. The technoeconomic
analysis of different feasible supply configurations of the
charging station using renewable energies is simulated using
HOMER software and the results compared in order to select the best
possible charging strategies in terms of cost of energy consumed.