scholarly journals Load-Independent Voltage Balancing of Multi-Level Flying Capacitor Converters in Quasi-2-Level Operation

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2414
Author(s):  
Piotr Czyz ◽  
Panteleimon Papamanolis ◽  
Francesc Trunas Trunas Bruguera ◽  
Thomas Guillod ◽  
Florian Krismer ◽  
...  
Keyword(s):  
Predictive Control ◽  
Cell Voltage ◽  
Load Current ◽  
Voltage Balancing ◽  
Power Semiconductors ◽  
Zero Current ◽  
Flying Capacitors ◽  
Multi Level ◽  
The Individual ◽  
Multiple Switching

Quasi-2-level (Q2L) operation of multi-level bridge-legs, especially of flying-capacitor converters (FCC), is an interesting option for realizing single-cell power conversion in applications whose system voltages exceed the ratings of available power semiconductors. To ensure equal voltage sharing among a Q2L-FCC’s switches, the voltages of a Q2L-FCC’s minimized flying capacitors (FCs) must always be balanced. Thus, we propose a concept for load-independent FC voltage balancing: For non-zero load current, we use a model predictive control (MPC) approach to identify the commutation sequence of the individual switches within a Q2L transition that minimizes the FC or cell voltage errors. In case of zero load current, we employ a novel MPC-based approach using cell multiple switching (CMS), i.e., the insertion of additional zero-current commutations within a Q2L transition, to exchange charge between the FCs via the charging currents of the switches’ parasitic capacitances. Experiments with a 5-level FCC half-bridge demonstrator confirm the validity of the derived models and verify the performance of the proposed load-independent balancing concept.

scholarly journals A Multi-level Review of Engineering Ethics Education: Towards a Socio-technical Orientation of Engineering Education for Ethics

2021 ◽  
Vol 27 (5) ◽  
Author(s):  
Diana Adela Martin ◽  
Eddie Conlon ◽  
Brian Bowe
Keyword(s):  
Engineering Education ◽  
Ethics Education ◽  
Engineering Ethics ◽  
Theoretical Research ◽  
Policy And Practice ◽  
Individual Level ◽  
Multi Level ◽  
Engineering Ethics Education ◽  
Four Levels ◽  
The Individual

AbstractThis paper aims to review the empirical and theoretical research on engineering ethics education, by focusing on the challenges reported in the literature. The analysis is conducted at four levels of the engineering education system. First, the individual level is dedicated to findings about teaching practices reported by instructors. Second, the institutional level brings together findings about the implementation and presence of ethics within engineering programmes. Third, the level of policy situates findings about engineering ethics education in the context of accreditation. Finally, there is the level of the culture of engineering education. The multi-level analysis allows us to address some of the limitations of higher education research which tends to focus on individual actors such as instructors or remains focused on the levels of policy and practice without examining the deeper levels of paradigm and purpose guiding them. Our approach links some of the challenges of engineering ethics education with wider debates about its guiding paradigms. The main contribution of the paper is to situate the analysis of the theoretical and empirical findings reported in the literature on engineering ethics education in the context of broader discussions about the purpose of engineering education and the aims of reform programmes. We conclude by putting forward a series of recommendations for a socio-technical oriented reform of engineering education for ethics.

scholarly journals Improved Modeling of a Multi-Level Inverter for TACS to Reduce Computational Time and Improve Accuracy

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 849
Author(s):  
Sung-An Kim
Keyword(s):  
Mechanical Model ◽  
Simulation Software ◽  
Computational Time ◽  
Electrical Model ◽  
Conventional Model ◽  
Switching Operation ◽  
Air Compressor ◽  
Power Semiconductors ◽  
Proposed Model ◽  
Multi Level

A modeling of a turbo air compressor system (TACS), with a multi-level inverter for driving variable speed, combining an electrical model of an electric motor drive system (EMDS) and a mechanical model of a turbo air compressor, is essential to accurately analyze dynamics characteristics. Compared to the mechanical model, the electrical model has a short sampling time due to the high frequency switching operation of the numerous power semiconductors inside the multi-level inverter. This causes the problem of increased computational time for dynamic characteristics analysis of TACS. To solve this problem, the conventional model of the multi-level inverter has been proposed to simplify the switching operation of the power semiconductors, however it has low accuracy because it does not consider pulse width modulation (PWM) operation. Therefore, this paper proposes an improved modeling of the multi-level inverter for TACS to reduce computational time and improve the accuracy of electrical and mechanical responses. In order to verify the reduced computational time of the proposed model, the conventional model using the simplified model is compared and analyzed using an electronic circuit simulation software PSIM. Then, the improved accuracy of the proposed model is verified by comparison with the experimental results.

scholarly journals Multi-level Governance and Energy Specifics of the V4 Countries within the Context of European Integration

2020 ◽  
Vol 16 (2) ◽  
pp. 525-546
Author(s):  
Helena Bauerová ◽  
Milan Vošta
Keyword(s):  
European Integration ◽  
Energy Policy ◽  
State Level ◽  
Theoretical Concept ◽  
Levels Of Analysis ◽  
Energy Mix ◽  
Strategic Plans ◽  
Multi Level ◽  
The Individual ◽  
The Eu

AbstractThe topic of energy is still one of the most sensitive policy areas. The aim of this article is to examine the multi-level governance and energy specifics of the V4 countries within the context of European integration by analyzing selected the specifics of the energy mix of the V4 group countries. This will be carried out within the context of applying the theory of multilevel governance. The paper shows how energy policy is formed at state, and/or non-state level, as well as how these levels are influenced by the EU. The article also looks at the efforts taken to shape a common energy policy. A closer examination of the individual countries‘ levels lies outside the scope of this article. Therefore, the framework was chosen with regard to the particular features within the context of the functioning of the V4 group of countries. Using multi-level governance as a theoretical concept, the authors considered the limits arising from the determination of levels and the subjects of the survey, as well as having distinguished three levels of analysis. The first is the supranational level. This is represented by the EU. The second level is represented by the V4 states. The third level is the state as the actor that formulates energy policy, sets the energy mix and subsequently manifests itself in relation to the EU and the V4 group. Energy policy is significantly influenced by states, especially in the area of energy security of fuel supplies, or that of setting the energy mix. With the gradual communitarization of energy policy, the EU’s influence is growing and it is debatable how the evaluation of existing strategic plans, presented by individual states, will be done. The role of the V4 group is the weakest of the three levels of analysis which were examined. However, its increasing influence can be predicted mainly in the case of coal depletion and the perception of nuclear energy as a renewable source.

scholarly journals Isolated individuals and groups show opposite preferences toward humidity

2018 ◽  
Author(s):  
Mariano Calvo Martín ◽  
Stamatios C. Nicolis ◽  
Isaac Planas-Sitjà ◽  
Jean-Christophe de Biseau ◽  
Jean-Louis Deneubourg
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Group Level ◽  
Individual Level ◽  
Negative Effect ◽  
Multi Level ◽  
The Individual ◽  
Shed Light ◽  
Selection Of

AbstractCockroaches, like most social arthropods, are led to choose collectively among different alternative resting places. These decisions are modulated by different factors, such as environmental conditions (temperature, relative humidity) and sociality (groups size, nature of communications). The aim of this study is to establish the interplay between environmental conditions and the modulation of the interactions between individuals within a group leading to an inversion of preferences. We show that the preferences of isolated cockroaches and groups of 16 individuals, on the selection of the relative humidity of a shelter are inversed and shed light on the mechanisms involved. We suggest that the relative humidity has a multi-level influence on cockroaches, manifested as an attractant effect at the individual level and as a negative effect at the group level, modulating the interactions.

scholarly journals Design and testing of stability improvement of nine multi-level H-Inverter for distribution system

2019 ◽  
Vol 8 (4) ◽  
pp. 245 ◽  
Author(s):  
R. Arulmurugan
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Phase Distribution ◽  
Dynamic Compensation ◽  
Load Current ◽  
Energy Compensation ◽  
Multi Level ◽  
Solitary Phase ◽  
Design And Testing ◽  
Reference Input

<p class="Abstract">In this article, a solitary phase nine-level series connected H-Bridge powered by photovoltaic MPPT based SHAPF in view of basic controller is proposed. SRF is utilized for reference input current extraction and to create pulses for the SHAPF. The principle point of the cascaded bridge is to dispense harmonics, enhance power factor and reactive energy compensation of the single-phase distribution framework. The suggested control calculation has two parts, changing the load current into stationary reference outline directions and estimation of peak amplitude of load currents. Consequently, a basic and dependable controller effortlessly of execution was created. The calculation for single-phase SHAF is intending to perform with exact tracking performance under step changes in load currents and to give great dynamic compensation. In this article, synchronous reference theory PLL with Inverse-Park change is adopted for producing quadrature part of current. The execution of the control calculation is tried and assessed utilizing MATLAB/Simulink tool.</p>

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