Hernaldo Saldías Molina, Juan Dixon Rojas and Luis Morán Tamayo
The purpose of this paper is to implement a finite set model predictive control algorithm to a shunt (or parallel), multilevel (cascaded H-bridge) active power filter (APF)…
Abstract
Purpose
The purpose of this paper is to implement a finite set model predictive control algorithm to a shunt (or parallel), multilevel (cascaded H-bridge) active power filter (APF). Specifically, the purpose is to get a controller that could compensate the mains current and, at the same time, to control the voltages of its capacitors. This strategy avoids the use of multiple PWM carriers or another type of special modulator, and requires a relatively low processing power.
Design/methodology/approach
This paper is focussed in the application of the predictive controller to a single-phase parallel APF composed for two H-bridges connected in series. The same methodology can be applied to a three-phase APF. In the DC buses of each H-bridge, a floating capacitor was connected, whose voltage is regulated by the predictive controller. The controller is composed by, first, a model for the charge/discharge dynamics for each floating capacitor and a model for the output current of the APF; second, a cost function; and third, an optimization algorithm that is able to control all these variables at the same time, choosing in each sample period the best combination of firing pulses.
Findings
The controller can track the voltage references, compensate the current harmonics and compensate reactive power with an algorithm that evaluates only the three nearest voltage levels to the last voltage level applied in the inverter. This strategy decreases the number of calculations required by the predictive algorithm. This controller can be applied to the general case of a single-phase multilevel APF of N-levels and extend it to the three-phase case without major problems.
Research limitations/implications
The implemented controller, when the authors consider a constant sample time, gives a mains current with a Total Harmonic Distortion (THD-I) slightly greater in comparison with the base algorithm (that evaluates all the voltage levels). However, when the authors consider the processing times under the same processor, the implemented algorithm requires less time to get the optimal values, can get lower sampling times and then a best performance in terms of THD-I. To implement the controller in a three-phase APF, a faster Digital Signal Processor would be required.
Originality/value
The implemented solution uses a model for the charge/discharge of the capacitors and for the filter current that enable to operate the cascaded multilevel inverter with asymmetrical voltages while compensates the mains currents, with a predictive algorithm that requires a relatively low amount of calculations.
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José Luis Camarena, Francisco Javier Osorio Vera, Hector Heraldo Rojas Jimenez, Ernesto Borda Medina, Juan Camilo Esteban Torregroza and Jesús David Tabares-Valencia
This paper aims to propose future public policy guidelines (FPPG) in sustainable regional development for Guaviare (Colombia) – a territory affected by environmental and social…
Abstract
Purpose
This paper aims to propose future public policy guidelines (FPPG) in sustainable regional development for Guaviare (Colombia) – a territory affected by environmental and social distress – for the year 2035.
Design/methodology/approach
Following collective action theory and sustainable regional development literature, a foresight exercise was conducted using site focus groups and semi-structured interviews with local participants to identify future strategic change drivers and the most relevant social actors for the attainment of economic, social and environmental development in the Guaviare through FPPG.
Findings
The findings suggest that the development of public policies regarding building consensus around Guaviare’s economic, environmental and social issues, reducing conflict between the region’s cultural and environmental ways, decreasing isolation from the centers of decision-making, increasing the transparency of public institutions and reducing insecurity to attract investments are all crucial to attaining sustainable regional development.
Originality/value
Interdisciplinarity is implicit in the local perspectives on the problem that impedes sustainable development in San José del Guaviare. The paper’s main contribution is the long-term vision that breaks away from the traditional short-termism in public policy guidelines in a Latin American context. Methodologically, the significant contribution is the convergent alignment of specific foresight methods toward public policy guidelines’ analysis and design processes.
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Mohammad Pourebrahimi, Seyed Rahman Eghbali and Ana Pereira Roders
Obsolescence is a decline or loss of utility of an object, building or product. Different types of building obsolescence decrease buildings’ utility and shorten their service…
Abstract
Purpose
Obsolescence is a decline or loss of utility of an object, building or product. Different types of building obsolescence decrease buildings’ utility and shorten their service life. The purpose of this paper is identification of building obsolescence types and the relevant factors that affect buildings to become obsolete. It is also intended to categorise building obsolescence types to provide a contribution towards increasing building service life and delivering sustainability.
Design/methodology/approach
A systematic literature review is applied to conduct this research. It follows five steps: (1) formulating the research question; (2) locating studies; (3) selecting and evaluating relevant studies; (4) analysing the findings; (5) reporting and making use of the results.
Findings
Via this study, it is revealed that there are 33 types of building obsolescence. They are clustered in 10 categories regarding their conceptual and causing aspects and are presented based on their recurrence in the literature. According to the findings, economic obsolescence (including economic, financial and market obsolescence types) and functional obsolescence (including functional, use and utility obsolescence types) are the most remarkable categories.
Originality/value
Investigating the literature makes it clear that building obsolescence types have been studied intermittently with infrequent profound exploration of the relationship between them. This paper presents a comprehensive identification of building obsolescence types and introduces obsolescence categories that classify connected obsolescence types. It is a new framework for further studies on building obsolescence to find more effective prevention strategies to mitigate social, economic and environmental consequences of building obsolescence.
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The purpose of this paper is to compare the sustainability practices of Islamic and conventional banks, with the aim of evaluating whether their Corporate Social Responsibility…
Abstract
Purpose
The purpose of this paper is to compare the sustainability practices of Islamic and conventional banks, with the aim of evaluating whether their Corporate Social Responsibility (CSR) strategies converge or diverge in response to formal and informal institutions in an emerging country.
Design/methodology/approach
Drawing on institutional theory, this study contextualizes the competitive scenario through the National Business System (NBS) framework, and showcases the CSR strategies employed by large conventional and Islamic banks in Turkey. CSR patterns are examined from different angles such as motivations, strategy, actions and institutional results.
Findings
Within the same institutional environment, Islamic and non-Islamic banks combine convergent and divergent models to accommodate institutional realities in their CSR policies. Islamic banks exhibit an implicit commitment to CSR that is mostly based on informal institutions, whereas conventional banks use explicit CSR strategies as a means to fill the voids in formal institutions. In addition, philanthropy-oriented CSR prevails in Islamic banks, as opposed to the CSR actions associated with core business that are followed by conventional banks.
Social implications
An increased focus on formal institutions and explicit CSR actions by Islamic banks may further contribute to social well-being in emerging countries.
Originality/value
This study contributes to the paucity of research, from an institutional perspective, related to CSR practices amongst Islamic and conventional banks in emerging countries.
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Asael Islas-Moreno, Daniel Emigdio Uriza-Ávila, Ana Lieseld Guzmán-Elizalde and Gabriel Aguirre-Álvarez
The study aims to analyze the effect of the previous preparation and the work carried out in the field during a study trip on the development of competencies in agribusiness…
Abstract
Purpose
The study aims to analyze the effect of the previous preparation and the work carried out in the field during a study trip on the development of competencies in agribusiness students.
Design/methodology/approach
The destination was the pineapple area of the Papaloapan Lower Basin in Mexico, and 42 students from 6 different semester levels participated. The students answered a test prior to the trip, received an evaluation for their activities in the field and prepared reports and posters as products of the experience. The relationship between the scores obtained was examined through a comparative analysis.
Findings
The findings are framed in the cyclical model of experiential learning with four stages (feeling, watching, thinking and doing) by Kolb (1984). It is found that the acquisition of specific knowledge about what the experience will entail leads to better preparation, motivation and confidence to live the experience (potentiation of feeling and watching). In turn, specific knowledge and better use of experience promote the development of problem solving, interpersonal and communication skills (potentiation of thinking and doing).
Research limitations/implications
Statistical representativeness is not a quality of the study since it is based on a comparative analysis.
Originality/value
The study analyzes an educational component of great value in the business area, about which little is known in the agribusiness subarea.