scholarly journals Novel Step-Up Topologies of Zigzag Autotransformer

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3071
Author(s):  
Jiarong Wang ◽  
Bo He

Zigzag autotransformer is widely used in multi-pulse rectifier system. However, the traditional zigzag autotransformer does not have the step-up function. Meanwhile, by improving the zigzag autotransformer structure, the output voltage can be increased without additional auxiliary components. Therefore, based on the 12 pulse rectifier system, this paper analyzes and designs three zigzag autotransformer step-up topologies, establishes the corresponding mathematical topology, studies the relationship between the transformation ratio and system main parameters, and deduces the step-up range of the three topologies. When the transformation ratio is greater than or equal to 1.0353 and less than 2.0705 and when the transformation ratio is greater than or equal to 2.0705, the equivalent capacity of the three topologies are compared. Based on the comparison, the optimal topology is obtained in different cases. Finally, according to the theoretical analysis, the simulation parameters are set, the simulation circuit is built, and the results are analyzed combined with corresponding mathematical topologies.

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2139 ◽  
Author(s):  
Shahin Honarmand ◽  
Amirhossein Rajaei ◽  
Mahdi Shahparasti ◽  
Alvaro Luna ◽  
Edris Pouresmaeil

Employing partial power processing (PPP) technique for quasi Z-source converter (QZSC) a new structure of the converter is presented. Using PPP technique although eliminates electrical insolation, but permits reducing voltage and current stress at the semiconductors, if compared with full power proposals. In this work, two PPP structures are discussed: A first one, similar to the basic topology, where the output voltage of the power converter is in series with the input voltage; and a second one, where the output is in series with the capacitor of the QZSC. This minor modification, which requires no extra elements, improves the power rating, voltage gain, and requires a lower transformation ratio. An experimental prototype of the proposed converter has been tested and the results are compared with other implementations, permitting to validate the theoretical analysis as well as the advantages that this proposal provides.


2014 ◽  
Vol 800-801 ◽  
pp. 788-792
Author(s):  
Yun Ping Cheng ◽  
Wen Ge Wu ◽  
Xue Rui Li ◽  
Xiao Jun Du

Monitoring cutting force in manufacturing operations is important for controlling cutting process and surface quality. In this paper, a thin film sensor embedded in metal was designed and embedded on the holder of tool to measure the force in machining operations. The Wheatstone bridge would produce the output voltage when the thin film caused deformation by cutting forces. The relationship between the output voltage and the deformation of beam was analyzed and derived with formula. The results showed that cutting force could be calculated according to the output voltage.


Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jinguo Liu ◽  
Xuebin Zhang ◽  
Jiahui Yu ◽  
Zhenyao Xu ◽  
Zhaojie Ju

As a new wireless energy transmission technology, magnetically coupled resonant wireless energy transmission system (MCRETS) is not easily affected by obstacles in the transmission process, and the transmission distance is relatively far. However, how to balance the relationship between transmission efficiency and power to achieve optimal performance is still a huge challenge. In addition, few studies have theoretically investigated the factors affecting the wireless energy transmission system to obtain an optimal solution. Here, through unprecedented theoretical analysis, we find the exact parameters of system optimization and verify them by simulation and experiments. First, the optimal topology of MCRETS is obtained through theoretical analysis and comparison of topologies. Second, to improve the transmission performance of MCRETS, its impact factors, including transmission distance, resonant frequency, relay coil, and relative position of launch and receiving coils, are analyzed in detail to get accurate parameters. Furthermore, based on the analysis, we propose an unprecedented concept for balancing optimal efficiency and power, which is named the power product. Finally, the effectiveness of the proposed method is verified through analysis and experimental results. These findings shed light on the relationship between efficiency and power and provide a comprehensive theoretical basis for subsequent research.


2014 ◽  
Vol 13 (12) ◽  
pp. 5199-5209
Author(s):  
Heba A. El-Khobby ◽  
Mostafa M. AbdElnaby ◽  
Abdel-Aziz Ibrahim Mahmoud HASSANIN ◽  
Abdallah D. Maziad

A development and evaluation the Cloud Computing (ClComp) of Ministry of Electricity and Energy of Egypt (MEEE) is presented in this paper. In order to be able to judge whether the ClComp of MEEE is competence, there is a need to develop criteria which performance can judged. Competency based standards and the ability to perform the activities within an occupation to the standard expected in the organization structure are presented. The key objective of Cloud Computing is to integrate Authorized Groups (AuthGs) development with the needs of the organization structures of MEEE. The ClComp of MEEE was developed jointly between the telecommunication information technology and ClComp services. Evaluation enables participant to distinguish between AuthGs centered view and a customer centered view of cloud computing of MEEE is competence evaluation. Recognize the main types of evaluation, explain the purpose of evaluation compare the approaches to cloud computing evaluation and review the relationship between the process and policy of evaluation are investigated. Microprocessor architecture presented an optimistic view of multicore scalability to develop the ClComp. Moreover this paper investigates the theoretical analysis of multiprocessor developing and scalability. The analysis was based on the laws of Amdahl's, Gustafson's, Hill's and Marty for fixed-workload condition. Moreover, challenged the difficulties to develop better cloud computing is taken into account. Also, multicore analysis of ClComp scalability, performance and power under fixed-time and memory-bound conditions are studied. These results complement existing studies and demonstrate that ClComp architectures are capable of extensive scalability and developing.


2021 ◽  
pp. 147490412110097
Author(s):  
Niels Åkerstrøm Andersen ◽  
Justine Grønbæk Pors

Taking a point of departure in the paradoxical fact that the increase in educational knowledge leads to an increase in uncertainty for educational organisations, this article explores how uncertainty and contingency have increasingly become an integral part of school governance. The article draws on Niklas Luhmann’s theory of ‘World Society’ as a functional differentiated society providing a range of different symbolic media for educational organisations. To trace the increase in the complexity of governing, we provide a historical account of the shifting couplings between schools and function systems. We show how the school becomes linked to an increasing number of symbolic media so that education becomes only one out of many other concerns. The article studies the consequences these shifting couplings have for how schools are governed and how they are expected to self-manage their relationship to different function systems. The article adds to existing studies of how education has become more and more differentiated with the argument that this has also led to new forms of couplings between schools and the education system with a number of important implications for the teaching profession.


2021 ◽  
Author(s):  
Nadiia Vientseva ◽  
◽  
Oleva Karapetrova

The article reports the results of the empirical study of the impact of volitional qualities development on the level of academic achievements of higher education institution students. The article gives a theoretical analysis of the main types of volitional qualities that affect the assimilation of educational material by students. There was established the level of their development and the relationship with academic achievements. The article also identifies the main psycho-pedagogical and organizational peculiarities that affect the success of mastering the knowledge by university students. The psychological and pedagogical recommendations for forming, developing and supporting the volitional sphere of students are developed.


2018 ◽  
Vol 17 (3) ◽  
pp. 89-102
Author(s):  
Md. Saiful Islam ◽  
Md. Rifat-Ul-Karim Shovon ◽  
Abdul Goffar Khan

This paper presents a comparative study of the application of Thyristor versus IGBT in AC-DC controlled power converter. Both simulation and practical experiment have been carried out to test the relationship between the average output voltage (Vdc) with firing angle (α, for Thyristor) and triggering pulse width (, for IGBT). Also the total harmonic distortion (THD) has been observed in both the cases. It is observed that IGBT based power converter introduces more harmonics in the system, in spite of more symmetrical output voltage wave shape.


2020 ◽  
Vol 11 (87) ◽  
Author(s):  
Tatiana Sidorenko ◽  
◽  
Natalia Grisenko ◽  

The article is devoted to the study of such an important psychological phenomenon as an attitude of women to their own motherhood. It is summarizes the study of the problem of motherhood in psychological science in general. The article analyzes the problem of the influence of the relationship with the mother in childhood on the formation of a woman's attitude to her own motherhood in adult age. It is illuminates views of foreign and national researchers on the study of this phenomenon, as well as the essence of different areas of research on this phenomenon. Based on the theoretical analysis of the literature on this topic, the concept of "motherhood", its content and psychological essence is studied. Cultural-historical, biological, physiological and psychological aspects to the study of motherhood are singled out. The main content of scientific views on the formation of the phenomenon of motherhood is generalized. The main factors influencing the development of a woman's maternal sphere and the formation of the attitude to one's own motherhood are analyzed and considered. The content of such basic concepts as "mother's image" and "maternal relations" is revealed. The psychological features of the formation of an adequate image of the mother in the theoretical analysis of the ontogenesis of the maternal sphere are analyzed. The article also reveals the dynamics of motherhood in ontogenesis. The types of maternal relations and their role in the life of a mature woman are determined, as well as the influence of these relations on the formation of a woman's attitude to her own motherhood. The influence of different types of relationships between women and their own mothers on the level of formation of their attitude to personal motherhood has been empirically studied. Two groups of women were studied, one group had a positive relationship with their own mother, and the other had a negative one. In the course of the research the differences between different types of maternal relations and the level of formation of a woman's personal attitude to motherhood are singled out.


Author(s):  
Jonathan Pugh

The introduction outlines the motivation for investigating the relationship between autonomy and rationality in contemporary bioethics, and maps the contours of a pre-theoretical understanding of autonomy, in preparation for the theoretical analysis to come. Having noted some apparent ambiguities and tensions within the widely accepted assumption that there is a close relationship between autonomy and rationality, the author briefly distinguishes procedural and substantive accounts of autonomy, and identifies Beauchamp and Childress’ pioneering work in the principles of biomedical ethics as providing the standard account of autonomy in bioethics. He outlines some objections to the standard account, and goes on to outline a framework that is used in the rest of the book for developing a rationalist account of autonomy that aims to avoid these objections.


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