In this article, an improved dc capacitor voltage balancing control is proposed for single-phase cascaded H-bridge (CHB) multilevel converters. Compared with conventional voltage balancing control ...methods, the proposed scheme has a comprehensive consideration of three aspects while balancing the capacitor voltages among H-bridges: coupling effect elimination, reactive power balancing, and dynamic performance improvement. First, the system mathematical model in the d-q reference frame is derived, and the relationship among duty cycle modifications of H-bridges is revealed to eliminate the coupling effect of voltage balancing control on the current control loop. Then, based on the H-bridge power model, a quantitative solution for reactive power balancing is presented to design the reactive duty cycle modifications. In order to enhance the dynamic performance of voltage balancing control, a dynamic references design method is adopted to evaluate the active duty cycle modifications. Finally, both simulation and experimental results are presented to validate the effectiveness of the proposed scheme.
This article explores a single-source UXE-type asymmetrical multilevel inverter for its operation on 13-, 11-, and 9-levels with boosted output voltage. The 13- and 11-level operations require a ...single voltage sensor to maintain the auxiliary dc link at <inline-formula><tex-math notation="LaTeX">V_{\text{dc}}/2</tex-math></inline-formula> and produce 1.5 and 1.25 boosting using redundant states and exhibit lower capacitor inrush currents. For the 9-level operation, the topology exhibits self-balancing of the dc-link at <inline-formula><tex-math notation="LaTeX">V_{\text{dc}}</tex-math></inline-formula> and a boosting of 2. With a conventional pulsewidth modulation (PWM) for the 13-level operation, the inverter can drive a predominantly inductive load of 0.35 lagging at unity modulation index. For the 11-level operation, the levels cease to maintain beyond the modulation of 0.95. Thus, a hybrid PWM is proposed to fully utilize the redundant states for the charging of the switched-capacitors and enhance the inverter active load capability in the 13-level mode by 21% at unity modulation index (<inline-formula><tex-math notation="LaTeX">m_a</tex-math></inline-formula>) and address a 0.8 power factor load at the <inline-formula><tex-math notation="LaTeX">m_a</tex-math></inline-formula> of 0.9. For the 11-level operation, the levels are maintained at any <inline-formula><tex-math notation="LaTeX">m_a</tex-math></inline-formula> with the hybrid PWM. The operation of the inverter is also verified for nonlinear load. Further, the 9-level operation with twice boosting and self-balancing is presented. The results are verified on MATLAB/Simulink and validated experimentally.
A capacitor voltage-balancing method for a nested neutral point clamped (NNPC) inverter is proposed in this paper. The NNPC inverter is a newly developed four-level voltage-source inverter for ...medium-voltage applications with properties such as operating over a wide range of voltages (2.4-7.2 kV) without the need for connecting power semiconductor in series and high-quality output voltage. The NNPC topology has two flying capacitors in each leg. In order to ensure that the inverter can operate normally and all switching devices share identical voltage stress, the voltage across each capacitor should be controlled and maintained at one-third of dc bus voltage. The proposed capacitor voltage-balancing method takes advantage of redundancy in phase switching states to control and balance flying capacitor voltages. Simple and effective logic tables are developed for the balancing control. The proposed method is easy to implement and needs very few computations. Moreover, the method is suitable for and easy to integrate with different pulse width modulation schemes. The effectiveness and feasibility of the proposed method is verified by simulation and experiment.
Easy and effective usage of computational resources is crucial for scientific calculations, both from the perspectives of timeliness and economic efficiency. This work proposes a bi‐level ...optimization framework to optimize the computational sequences. Machine‐learning (ML) assisted static load‐balancing, and different dynamic load‐balancing algorithms can be integrated. Consequently, the computational and scheduling engine of the ParaEngine is developed to invoke optimized quantum chemical (QC) calculations. Illustrated benchmark calculations include high‐throughput drug suit, solvent model, P38 protein, and SARS‐CoV‐2 systems. The results show that the usage rate of given computational resources for high throughput and large‐scale fragmentation QC calculations can primarily profit, and faster accomplishing computational tasks can be expected when employing high‐performance computing (HPC) clusters.
We present a procedure for easy and effective implementations of quantum chemical (QC) calculations benefited from machine‐learning assisted scheduling optimization and different load‐balancing algorithms. Employing this procedure, we showed that the high throughput and large‐scale fragmentation QC calculations can primarily profit, and faster accomplishing computational tasks can be expected when employing HPC clusters.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
In this paper, I investigate how and why experienced paradoxical tension deteriorates coopetitive performance and when such debilitating effects can be managed. More specifically, by drawing on the ...paradox theory and emotion literature, I suggest that paradoxical tension (i.e., the cognitive difficulty faced by senior managers as they pursue multiple, simultaneous competing demands of coopetition) creates a state of emotional ambivalence, which in turn, contributes negatively to coopetitive performance. I further propose that the negative consequences can be managed through organizational-level mechanisms, namely, emotional capability and balancing capability. The results show a full mediation of emotional ambivalence and a positive influence of balancing capability. Surprisingly, the moderating effect of emotional capability turns out to be negative. However, interestingly, the moderated-mediation result shows that a blend of higher balancing capability and lower emotional capability produces a positive indirect effect of tension on performance. The paper contributes to the research on strategy and organizational paradoxes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, we define the generalized k-balancing numbers {B(k)n } and k Lucas balancing numbers {C(k)n } and associated polynomials, where n is of the form sk+r, 0 ≤ r < k. We give several ...formulas for these new sequences in terms of classic balancing and Lucas balancing numbers and study their properties. Moreover, we give a Binet style formula, Cassini’s identity, and binomial sums of these sequences. KCI Citation Count: 0
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
This paper deals with the mechanism of space-vector pulse-width-modulation (SVPM) for a balanced two-phase induction motor in detail. It explains how the waveforms of the voltages applied to the two ...phases derive from the SVPWM .
El trabajo estudia el papel de los principios constitucionales en la aplicación ordinaria del Derecho; se centra, por tanto, en las relaciones entre ponderación y legislación. Para ello, se recurre a ...la teoría de la legislación de M. Atienza como punto de partida y se analizan algunos modelos teóricos. El artículo se propone sobre todo operar una simplificación drástica de la discusión teórica sobre la ponderación. Se concluyen dos tesis relativas al método jurídico en un Estado constitucional. Primera, los principios constitucionales son mandatos de ponderación dirigidos al legislador. Segunda, para los jueces ordinarios la ponderación contra legem está prohibida; la ponderación secundum legem es obligatoria; y la ponderación praeter legem es aceptable si el juez justifica la existencia de una laguna legislativa (ya sea normativa o axiológica).
This article proposes a two-mode active balancing circuit for series-connected cell strings. The proposed balancing circuit has two operation modes: any cell to any cell (AC2AC) and direct cell to ...cell (DC2C) modes. In AC2AC mode, the balancing circuit can be equivalent to an improved switched-capacitor (SC) balancing circuit, and the energy is transferred among all imbalanced cells, implementing the higher balancing speed when the voltage gap between cells and the number of imbalanced cells are large. In DC2C mode, the proposed balancing circuit can be equivalent to a balancing circuit based on three-resonant-state LC unit, and the energy is transferred from the highest voltage cell to the lowest voltage one, achieving the higher balancing efficiency and speed as well as accuracy when the voltage gap between cells is small. The operation state, balancing power, and balancing efficiency of each mode are analyzed in detail. The control strategy and design considerations of the balancing circuit are introduced to obtain the optimal balancing performance. Experimental results are provided to verify the validity of the proposed balancing circuit. The results show that the proposed balancing circuit achieves high balancing accuracy and efficiency as well as balancing speed.
The disassembly line plays a vital role to recover the products for remanufacturing enterprises. For this reason, designing and balancing of the disassembly line are important to utilize the economic ...and tactical benefits. This study explores a multi-objective disassembly line balancing problem (MODLBP) from a different point of view by considering the workers’ heterogeneity and the multi-manned stations where the group-based worker assignment strategy is implemented. Although the MODLBP has been attracting attention in the last decade, to the best of our knowledge, this is the first study investigating the addressed problem in the current form. To further analyze the problem, first, it is described by focusing on the tactical level strategies and operational level scenarios. Subsequently, a novel multi-objective optimization model is formulated with three objectives, that of minimizing overall cost, cycle time, and workload imbalance. On one hand, the improved augmented ϵ-constrained (AUGMECON2) method is used to obtain the Pareto-optimal solutions for small-sized problems. On the other hand, a set of algorithms based on the non-dominated sorting genetic algorithm-II is implemented to gain managerial insights regarding the strategies and scenarios for large-sized problems. A computational study is conducted based on the generated problems to reveal the prominent differences between strategies in terms of performance metrics. According to the computational results, high-quality solutions are achieved when the group-based assignment strategy is realized. Besides, it is revealed from scenario analysis that the training of workers leads to considerable improvements in the system performance.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
