Nuevas propuestas en la teoría de la potencia reactiva instantánea : aplicación a la compensación de cargas industriales con filtros activos de potencia

Se presentan y estudian las formulaciones más relevantes de la teoría de control, que se aplica a la compensación de cargas trifásicas no lineales en sistemas de cuatro conductores, tanto a nivel de simulación como experimental. Los resultados obtenidos se utilizan para realizar un estudio comparativo en el que se pone de manifiesto que ninguna permite obtener intensidades de fuente equilibradas y sinusoidales para cualesquiera condiciones en las tensiones de alimentación. No obstante, en esta tesis se proponen estrategias de control que consiguen alcanzar diferentes objetivos de compensación en cada contexto: potencia de fuente de constante, factor de potencia unidad e intensidad de fuente equilibrada y sinusoidal. Por último, en esta tesis doctoral se ha desarrollado una nueva propuesta de la teoría de la potencia reactiva instantánea que se denomina formulación tensorial aplicable a sistemas polifásicos.______________________________________________The most relevant formulations of the instantaneous reactive power theory are presented and studied.Each one is analyzed to obtain its control strategy, that is applied to the compensation of three-phase nonlinear loads in four-wire systems, as much concerning simulation as experimental. The obtained results are used to carry out a comparative study in which it is shown that no strategy allows to obtain balanced and sinusoidal source current for any conditions in the supply voltage. However, in this thesis, several control strategies are presented that are able to obtain different objectives from compensation in each context: constant source power, unity power factor and balanced and sinusoidal source current. Finally, in this work, a new approach of the instantaneous reactive power theory has been developed that is named tensorial and is applicable to multiphase systems

Instantaneous Reactive Power Theory: A Reference in the Nonlinear Loads Compensation

The instantaneous reactive power theory was published 25 years ago, in an IEEE Transactions. Since then, it has been the most used in nonlinear load compensation with active power filters. Its application allows constant source power to be obtained after compensation in a simple way. Moreover, some researches have showed up some limitations of the theory, i.e., it goes optimally with source voltage balanced and sinusoidal, but not so good with source voltage unbalanced and/or nonsinusoidal, since the source current obtained is not balanced and sinusoidal. This paper presents a new compensation strategy in phase coordinates, equivalent to the original theory's one. Its simplicity, due to the nonnecessity of coordinate mathematical transformation, makes easier the modifications necessary to obtain alternative compensation objectives. In this way, this paper presents those modifications and derives compensation strategies that obtain alternative compensation objectives: unity power factor or balanced and sinusoidal source current. Finally, compensation strategies are applied to a practical power system, and the results are presented

Rethinking the Resources and Responsibilities of University Spin-Offs: Critical Factors in Times of Global Crisis

In recent years, the promotion of university spin-offs has become a measure adopted by many European universities to facilitate the commercialization of new technologies and knowledge that can lead to more sustainable economies and societies. However, the effectiveness of universitybased companies has also been questioned, as many of them are resource-constrained, remain small in size and struggle to consolidate once they leave the university context. This paper addresses two main research questions: what are the critical factors inhibiting the consolidation, performance, and sustainable development of university spin-offs at a mid-range European university, and which critical factors need to be addressed the most thoroughly by the university’s support programs in order to improve their efficiency? To answer these questions, we collected relevant information from a panel of experts and interviewed academic entrepreneurs from a public university in the South of Spain. The analytic hierarchy process was applied to identify and prioritize the critical factors and sub-factors encountered by the university-based companies. The results show that poor management is the biggest critical factor in the consolidation of the spin-offs. One implication, the findings of our study reveal, is the need for university administrators to improve support for university spin-offs in terms of managing the new business as opposed to prioritizing the difficulties associated with the launch. Another is the need to raise awareness among faculties of the importance of finding an appropriate balance between technical and managerial skills in order to improve the chances of entrepreneurial succes

Practical Design of a Load Compensation Active Conditioner

This paper presents the obtained experimental results with a single-phase experimental prototype of a Load Compensation Active Conditioner, sLCAC. The sLCAC is composed by a series – parallel combination of active power filters, and its main objective is the global conditioning of a load against harmonic distortion. On the one hand, to isolate the load voltage vL from the harmonics in the supply voltage vS, as well as to regulate it to the nominal value. On the other hand, to improve the supply current iS, compensating the harmonic and reactive components of the load current iL. An experimental prototype has been implemented, and the obtained results are presented to support the performance of the proposed design

Non-Linear and Unbalanced Three-Phase Load Static Compensation with Asymmetrical and Non Sinusoidal Supply

P-q theory has been widely used to control active power filters since its formulation in 1983. The compensation strategy used by the p-q theory users has not suffered modification; so it is used the constant power compensation strategy. In this way, the supply instantaneous power after compensation is constant. This kind of compensation strategy has obtained good results in the case of balanced and sinusoidal voltages, however it has not been appropriate in the case of unbalanced or non sinusoidal voltages. In this paper it has been researched about the modifications necessary, into the p-q theory frame, to get control strategies which allow to attack the unit power factor compensation or the balanced and sinusoidal currents compensation

Testing Bench for Remote Practical Training in Electric Machines

Remote labs are emerging as a necessary tool to support practical classes in engineering studies. It is due to the increasing number of students who combine their studies with work. In fact, there are numerous developments in areas such as electronics and automatic. However, there are only a few of them in the area of electrical machines. This paper presents a testing bench for remote practical training in electric machines. The security challenges presented by these experiments are overcome by software within the remote lab. In addition, a friendly interface has been designed including augmented reality to identify the different elements and to provide information on these items if the student requires it. The testing bench has been developed to be used in different kinds of electrical machines test

The Remote Access to Laboratories: a Fully Open Integrated System

An existing lab experience can be made remotely accessible in a relatively easy way. The problem is with the design of a tool which allows any kind of experience to be made remotely accessible. The complexity of this tool is out of discussion. Several universities have been working on it for years. In fact, the Huelva University presented the work “A Complete Solution for Developing Remote Labs†in the 10th IFAC Symposium on Advances in Control Education (2013). Such complete solution was the result of those universities working together. Since then, the joint-work has continued and improvements have also been achieved. Hereafter, a fully open integrated system is presented whose scope is greater than that of 2013. It offers a way to easily implement cloud services for managing the configuration and access to all type of sensors, actuators and controllers (the devices base of the any remote lab). The access proposed is secure, controlled, organized and collaborativ

A Complete Solution for Developing Remote Labs

The use of remote laboratories for education is increasing because it is a method that allows a better use of resources (laboratories operate 24 hours a day) and students interact with real equipment from different locations. However, we can say that there are as many particular solutions as remote labs can be found today. In this paper, we present a design framework for remote laboratories, covering the various aspects involved and completely based on free software. Within this approach, professors have all the tools required to convert a laboratory experiment in a remote experiment. Moreover, they can also design an user interface that includes augmented reality techniques to enrich the user experience

A Fully Integrated Open Solution for the Remote Operation of Pilot Plants

Nowadays remote access to systems in the instrumentation and measurement fields is both a reality and a challenge. There is a growing interest in replacing manual actions performed on site by remote actions carried out from anywhere around the world. To do that, besides the availability of suitable communication networks, it is necessary for the elements involved in the network to recognize each other, this latter task perhaps being the most complex one of the two. Integrating different hardware/software from different manufacturers into a single system with controlled remote access is not a trivial task. This paper presents a fully integrated open solution for the operation of pilot plants (scaled down, laboratory level industrial plants operated in university and other environments) using open access hardware/software on public networks. The proposed solution is independent of the nature of the pilot plant and its elements and can therefore be considered standard. In order to illustrate the capabilities of the proposed solution, two different types of pilot plant are presented

Complete and versatile remote controller for PV systems

The promotion of the distributed generation and the photovoltaic (PV) energy great potential put this technology in the spotlight of investors. Thus, the optimization of its efficiency is made a priority. In this paper, a complete and versatile remote controller (C&VRC) for PV systems is presented, scalable to any kind and size of installations (with or without partial shading, with or without connection to the grid, housing, small plants or even large-scale solar plants) and valid for any weather conditions. The C&VRC involves the controller itself, which is constituted by a set of sensors and actuators connected to the converters Direct Current (DC)/DC and DC/Alternating Current (AC), if necessary, and a control unit communicated with them through the third-generation mobile telecommunications technology (3G) network. The control strategies can be changed according to the different weather conditions and installations characteristics, which guaranties the optimum performance of the system. The use of the 3G network as communication platform makes the C&VRC useful in remote and low accessibility places, because it is the most extended worldwide. The C&VRC is also based on free software, open hardware and low-cost electronic devices. Experimental results are presented in this paper to show the C&VRC optimum usability.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA