scholarly journals Modulation Variants in DC Circuits of Power Rectifier Systems with Improved Quality of Energy Conversion—Part I

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1876
Author(s):  
Tomasz Pajchrowski ◽  
Michał Krystkowiak ◽  
Dominik Matecki
Keyword(s):  
Quality Improvement ◽  
Energy Conversion ◽  
Electric Power ◽  
Power Electronics ◽  
High Power ◽  
Current Source ◽  
Supporting System ◽  
Three Phase ◽  
Power Rectifier

The article presents various concepts of three-phase power rectifiers with improved quality of converted electric power. This effect is obtained by modulating the currents in the DC output circuits of the rectifiers by means of power electronics controlled voltage or current sources, working as a so-called voltage or current modulators. For further quality improvement of the grid currents of the analyzed systems, it was proposed to use an additional controlled current source connected in parallel to the DC load, hereinafter referred to as a supporting system. The original elaborated method of controlling this source (supporting system) was presented. The main goal of the work was to propose a solution for an effective method of improving the quality of energy conversion in rectifier systems, especially high power ones, by using controlled current sources in DC circuits, operating as the power electronics current modulator and the supporting system.

scholarly journals Evaluating the Effectiveness of New and Old Kinetic Energy Conversion from an Electric Power Economics Perspective: Evidence on the Shandong Province of China

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1174 ◽  
Author(s):  
Wanlei Xue ◽  
Bingkang Li ◽  
Yongqi Yang ◽  
Huiru Zhao ◽  
Nan Xu
Keyword(s):  
Economic Growth ◽  
Economic Development ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Electric Power ◽  
Evaluation Model ◽  
Three Dimensions ◽  
Effectiveness Evaluation ◽  
Close Attention

This paper proposes a hybrid model for evaluating the effectiveness of new and old kinetic energy conversion (NOKEC), China’s major strategic move aiming to transform the mode of economic growth and improvie the quality of economic development. Considering the goals of NOKEC and the supporting roles of power industry to NOKEC, this paper constructs an index system for NOKEC effectiveness evaluation from an electric power economics perspective, involving three dimensions and 17 secondary indicators. Furthermore, a hybrid evaluation model based on DEMATEL-ANP and DQ-GRA techniques is developed to accomplish the evaluation of Shandong’s NOKEC effectiveness. The results show that Shandong’s NOKEC effectiveness increased from 2015–2017, indicating that Shandong’s NOKEC policies have achieved remarkable results. According to the evaluation results, this paper puts forward the indicators that should be paid close attention to and the following work priorities in Shandong’s future NOKEC process, which has certain practical value for the promotion of Shandong’s NOKEC. In addition, the evaluation model proposed in this paper considers the interrelationships between indicators and overcomes the shortcomings of traditional GRA, showing good applicability to similar effectiveness evaluation issues. Finally, the limitations and universality of the model are discussed and the improvement direction is put forward.

scholarly journals $G$-deviations of polygons and their applications in Electric Power Engineering

2021 ◽  
Vol 55 (2) ◽  
pp. 188-200
Author(s):  
T. Banakh ◽  
O. Hryniv ◽  
V. Hudym
Keyword(s):  
Electric Power ◽  
Complex Plane ◽  
Metric Space ◽  
Power Engineering ◽  
Affine Transformations ◽  
Electric Power Engineering ◽  
Standard Characteristic ◽  
Three Phase ◽  
Measures Of Asymmetry

For any metric space $X$ endowed with the action of a group $G$, and two $n$-gons $\vec x=(x_1,\dots,x_n)\in X^n$ and $\vec y=(y_1,\dots,y_n)\in X^n$ in $X$, we introduce the $G$-deviation $d(G\vec x,\vec y\,)$ of $\vec x$ from $\vec y$ as the distance in $X^n$ from $\vec y$ to the $G$-orbit $G\vec x$ of $\vec x$ in the $n$-th power $X^n$ of $X$. For some groups $G$ of affine transformations of the complex plane, we deduce simple-to-apply formulas for calculating the $G$-deviation between $n$-gons on the complex plane. We apply these formulas for defining new measures of asymmetry of triangles. These new measures can be applied in Electric Power Engineering for evaluating the quality of 3-phase electric power. One of such measures, namely the affine deviation, is espressible via the unbalance degree, which is a standard characteristic of quality of three-phase electric power.

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