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In this paper a series of constants, corresponding to wireless power transfer system (WPTS), are defined, function of S parameters. These constants will be further used for stability factors computation in WPTS. To generate: the reflection coefficients, the standing wave ratio (SWR), the input and output impedances, the input and output active power transmission efficiency, the signal transmission...
This study, using the theory of electric circuits, shows the right definition of scattering parameters (S-parameters) for any two-port electric circuit and the practical way to use these parameters in streamline the processes of information transmission and propagation, and the transfer of the active power from the electric quadrupole input (output) to their output (input). Starting from the correct...
Switched networks modelling lead very often to discontinuities of circuit's variables corresponding to switching time moments. This phenomenon is said to have inconsistent initial conditions (IIC). The IIC problem appears only for ideal switches in ideal circuits when, after switching, the circuit contains excess elements. As a consequence, Dirac delta functions and their derivatives can occur in...
The wireless power transfer systems (WPTS) work at frequencies between 20 kHz – 40 MHz. Considering the system consisting of two magnetically coupled coils, used in WPTSs, as a passive linear two-port network (PL2PN) in harmonic state, this paper describes the possibility of using the scattering parameters S in generating the power gains between the two ports of these coils. The amplification (or...
This paper presents some aspects regarding the thermographic detection of early-stage cancer that can affect paired organs. The use of a difference thermal field on the surface of the skin near paired organs surfaces is proposed as part of a detection method. The temperature acquisition procedures based on the use of thermographic cameras and temperature sensors are analyzed. The symmetry of the thermal...
This paper presents the correct formulation of scattering parameters S, using electric circuit theory, and the practical use of these parameters. The purpose is to make more efficient the processes for the information transmission and the wireless electromagnetic energy transfer. The efficiency is seen from the transmission point of view of the signals (from the transmitter to receiver) and from the...
This paper presents a procedure to optimize the structure of the two magnetic coupled coils used in the wireless power transfer systems (WPTS's). The optimization of the two magnetic coupled coils is performed in function of the alignment coils. There are two forms of deviation in the alignment of coils — the lateral displacement and the angular displacement. In the lateral displacement, the two coils...
In this paper we present our research on several original circuits working as wireless power transfer systems (WPTS). All the circuits in the paper used sets of two magnetically coupled coils whose parameters were extracted by simulations using ANSOFT Q3D Extractor. The circuits were then simulated using TINA (DesignSoft), PSpice (Cadence Design) and Simulink in Matlab (Mathworks). We used existing...
This paper presents a procedure for wireless power transfer system (WPTS) parameter identification using ANSYS Extractor Q3D Program. For this, ANSYS Extractor Q3D Program is used to compute the C, L, R and G matrices, for different configurations, structures, frequencies and distances between coils. C and G - the matrices that are generated by the software from the field simulator outputs - are in...
In order to perform the magnetic field computation it is essential to know the B-H characteristic. This paper presents a new equipment to be used to determine the first magnetization characteristic of a ferromagnetic body. This equipment consists of an 8-shape magnetic circuit, having as unknown the B-H magnetic characteristic in the base horizontal yoke. The other branches have a known B-H characteristic,...
Piercing the cell membrane using an electric pulse (electroplasmolysis), in order to release the liquid within, is a modern food processing procedure. Obtaining the electric field required for piercing the cell, without needlessly increasing the energy consumption and without destroying the cell, requires the solution of a complicated electro-quasistationary electromagnetic field problem. The small...
A more intense metabolism of cancer cells versus normal cells may be an important source of heat which produces changes of the affected breast tissue thermal field. In very early tumors, when neoangiogenesis has not been developed yet, the thermal effect can be important for detection. The temperature changes on the breast surface can be measured and can serve as a breast cancer screening process...
The properties of some ferromagnetic materials are known by measurements made on samples using adequate instruments, and are offered by manufacturers or databases. The evaluation of unknown magnetic characteristics of ferromagnetic bodies cannot be directly made, due to the impossibility of collecting material samples. However, the B-H characteristics of these bodies influence the nearby field in...
In comparison with the Stirling machine, the thermoelectric generator (TEG), based on the Seebeck effect, allows the direct transformation of thermal energy into electric energy. TEG has no moving parts and it does not pollute. Unfortunately, its performance is much under the Stirling machine's efficiency, the main disadvantage being the low voltage of TEG. An important feature of TEG usage in space...
Based on a quasi-static magnetic field solution for a rotor winding carrying trapezoidal periodic currents, power losses analytical solution is discussed. The winding is placed in an open rectangular slot. Particular formulae for square and trapezoidal waveforms are also discussed.
Substance property modifications in materials can lead to failure by growing to a critical and self-propagating size. By knowing the dimensions of defects present in a component, it is possible to estimate both extent of degradation and remaining life of the component and defects' growth characteristics under operating conditions. Early detection and characterization of defects, micro-structural variations...
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