Analysis Of Different Topologies Research Articles

The Geometry of Coronary Artery Bifurcations and Its Role in Plaque Formation

The risk of cardiovascular diseases is determined by the deposition of plaque in the coronary arteries. The areas of plaque deposition are also controlled by the flow dynamics and, for this, the topology of the arterial bifurcations has shown to be crucial. We present a detailed analysis of different topologies at the bifurcation based on numerical simulations of a mathematical model. Different diameters of the involved vessels as well as angle between them are analyzed. Unexpectedly, the curvature of the walls connecting the vessels is observed to play an important role.

Comparison of Nano-second and Millisecond Pulse Generators for Biological applications of Electroporation

A phenomenon that transiently increases the permeability of the cells is known as electroporation. It is the basis for number of the applications in biomedical domains. It is essential to consider requirement of high precision and the overall size of electroporator. The recent decades have seen the development of solid-state power electronic modules. The modules enable generation of high voltage millisecond and nano-second pulses with options to reduce the overall size of the equipment. The selective modules are verified with experimental models and available for commercial usage. While the other modules are still undergoing optimization processes. The generator generates pulses for varying performances. Hence, this paper presents knowledge for different nanosecond and millisecond pulse generating circuits for electroporation purposes. The performance parameters like the width of the pulse, its amplitude are compared for different circuit topologies. The performance analysis of different topologies and their impact on the performance of the electroporation at the cell biology level are considered in this paper.

Comparative Analysis of Different Topologies of Linear Switched Reluctance Motor With Segmented Secondary for Vertical Actuation Systems

This paper presents the overall comparison of four possible topologies of linear switched reluctance motor with segmented secondary (LSRMSS) as candidates for vertical actuation systems. The analytical design approach which treats each unit of LSRM as independent force generator is applied to design the four machines. All the four machines can be seen as 2-unit force generator although they have different winding configurations and topologies. In this case, the four machines can be designed to have similar force profile due to the inherent modular characteristics of LSRMSS. Force production, active material mass, end effects, copper loss and thrust density have been considered as well as the dynamic performance. The results indicate that the topology with toroidally wound mover has the highest force density and payload ratio capability. This topology is finally chosen to be prototyped for a 1m long vertical propulsion actuator. The experiment is performed to validate the theoretical analysis above.

DC Microgrids: Architecture and Challenges

In the evolving era, microgrid wins the heart in all power fields. Among that DC configuration achieved more demand because of its less complex structure, low cost, more reliability and more power quality and last but not the least the control scheme is less complex than AC microgrid. Management of power and energy are the evolving traits adopted by researchers now a days. This paper mainly aims at the comparative analysis of different topologies, structure, and operational mode of DC microgrid. Despite the global energy crisis and the increasingly atmospheric pollution, distributed generation integration with renewable energy is becoming a potential trend in technology. Finally, attention has been paid to the recent challenges to the DC microgrid system.

Comparison of Inverter Topologies by Total Har-Monic Distortion of Output Voltage

This paper is devoted to comparison analysis of different topologies of the inverters that are used in the systems with alternative energy sources. A brief theoretical review of the most commonly used topologies for the power systems with alternative energy sources are given, their main advantages and disadvantages are determined. In close details were considered principles of construction and operation of the topology with impedance input circuit (z-inverter), and topology with quasi-impedance input circuit (quasi-z-inverter). A special feature of these topologies is ability to operate in special mode which is called “shoot-trough state”. It means that one of the inverter’s arms is short-circuited for a small period of time which substitutes a part of the zero state. Possibility to operate in such state allows to increase the input voltage of the inverter that can be very suitable in inverters that are included in photovoltaic power systems. Implementation of shoot-trough state allows tracking maximum power point of the photovoltaic array without implementation of additional converters for this. Implementation of quasi-z-topology allows to reduce the load on the passive components of the impedance circuit and to ensure continuous power take-off from the solar batteries array, which makes it easier to track the maximum power point. As an evolution of the cascade multilevel and z- / quasi-z-inverter topologies multilevel cascaded topologies with z- and quasi-z-inverters in separate blocks were considered. The main principles of this structure allows to unite all advantages of cascaded multilevel and z-/quasi-z topologies in one device but also bring few drawbacks such as complexity of the implementation and higher cost of the resulting device. These topologies were simulated in Matlab Simulink, output voltage spectra and total harmonic distortion was obtained and analyzed. According to the obtained results of the simulation and review recommendations for proper selection of the topology of inverter depending on the type and sensitivity to the quality of the input voltage of the load and type of chosen alternative energy source are given. According to this results convenient cascaded multilevel topology could be recommended for the loads that are especially vulnerable to low quality of input supply voltage such as analog amplifiers and radio receivers as topology that have lowest THD (Total harmonic distortion) ratio. Z-/quasi-z-topologies are appropriate to consider as a converter of photovoltaic power system that will work on loads that are not demanding to the quality of supply voltage as topologies with highest level of THD of the output voltage. Cascaded topologies with z- and quasi-z-inverters in separate blocks could be considered as a compromise that could be used in photovoltaic power systems that works on vulnerable loads but such solution increases the cost of a whole power system and complication of the control system.

Analyzing Rural Electrification Topologies Based on Induced Voltage at Insulated Shielding Wires

This paper analyses low-cost techniques for rural electrification based on the use of insulated shielding wires of extra-high-voltage transmission lines. The main idea is to use the line capacitive coupling as an auxiliary power supply to remote rural systems. The insulated shielding wire (ISW) will behave as a capacitive voltage divider, promoting low voltage on it. We introduce a comparison of different low-cost electrification methods used over the last years and present a careful analysis of different topologies, which have a major impact on rural voltage regulation. A transient study was implemented to observe the behavior of both the transmission system and the rural feeder under typical switchings.

Assessment of Global Voltage Stability Margin through Radial Basis Function Neural Network

Dynamic operating conditions along with contingencies often present formidable challenges to the power engineers. Decisions pertaining to the control strategies taken by the system operators at energy management centre are based on the information about the system’s behavior. The application of ANN as a tool for voltage stability assessment is empirical because of its ability to do parallel data processing with high accuracy, fast response, and capability to model dynamic, nonlinear, and noisy data. This paper presents an effective methodology based on Radial Basis Function Neural Network (RBFN) to predict Global Voltage Stability Margin (GVSM), for any unseen loading condition of the system. GVSM is used to assess the overall voltage stability status of the power system. A comparative analysis of different topologies of ANN, namely, Feedforward Backprop (FFBP), Cascade Forward Backprop (CFB), Generalized Regression (GR), Layer Recurrent (LR), Nonlinear Autoregressive Exogenous (NARX), ELMAN Backprop, and Feedforward Distributed Time Delay Network (FFDTDN), is carried out on the basis of capability of the prediction of GVSM. The efficacy of RBFN is better than other networks, which is validated by taking the predictions of GVSM at different levels of Additive White Gaussian Noise (AWGN) in input features. The results obtained from ANNs are validated through the offline Newton Raphson (N-R) method. The proposed methodology is tested over IEEE 14-bus, IEEE 30-bus, and IEEE 118-bus test systems.

Proposal of High Gain, Reduced Stress with Low-Duty-Cycle Two-Input Boost Converter for Renewable Energy Systems

A two-input boost converter with voltage multiplier cell is proposed in this paper. Then a family of two-input converters with and without voltage multiplier cell are derived and their results are compared to achieve high voltage gain, low duty cycle, and reduced voltage stress. From the analysis of different topologies, a modified two-input converter with two-stage voltage multiplier cell has good operating characteristics. The switch voltage stress and duty cycle of the modified converter is significantly very less than that of the other converter topologies. The modified DC-DC converter with 50% duty cycle achieves a voltage gain of 10 and the results are verified by using MATLAB/Simulink software.

Internet-Enabled Calibration: An Analysis of Different Topologies and a Comparison of Two Different Approaches

This paper discusses different network topologies used in Internet-enabled metrology and calibration and explores and compares two different remote calibration systems used by the National Metrology Institutes in England and Norway: the National Physical Laboratory (NPL) and the Justervesenet (JV). The two systems are iGen (NPL) and iMet (JV). The systems both deal with remote calibration of electrical equipment but have substantial architecture differences. In iGen, calibration procedures are downloaded from a server and then locally run at the instrument client, where the operator sits. The client is generic in such a way that it is not dependent on the structure of the measurement procedures. In iMet, two clients can communicate via a public server, and the calibration process may be remotely controlled and monitored. That is, the instruments and the operator may be separated by the Internet.