This paper presents an educational software tool, called wtControlGUI, whose main purpose is to show the applicability and performance of different decoupling control strategies in wind turbines. Nowadays, wind turbines are a very important field in control engineering. Therefore, from an educational point of view, the tool also aims to improve the learning of multivariable control concepts applied on this field. In addition, wtControlGUI allows for testing and controlling of a lab-scale system which emulates the dynamic response of a large-scale wind turbine. The designed graphical user interface essentially allows simulation and experimental testing of decoupling networks and other multivariable methodologies, such as robust or decentralized control strategies. The tool is available for master degree students in control engineering. A survey was performed to evaluate the effectiveness of the proposed tool when it is used in educational related tasks. ß 2016 Wiley Periodicals, Inc. Comput Appl Eng Educ 24:400-411, 2016; View this article online at wileyonlinelibrary.com/journal/cae;

This work is focused on the improvement of variable-speed variable-pitch wind turbine performance by means of its control structure. This kind of systems can be considered as multivariable nonlinear processes subjected to undesired interactions between variables and presenting different dynamics at different operational zones. This interaction level and the dynamics uncertainties complicate the control system design. The aim of this work is developing multivariable controllers that cope with such problems. The study shows the applicability of different decoupling methodologies and provides a comparison with a H ∞ controller, which is an appropriate strategy to cope with uncertainties. The methodologies have been tested in simulation and verified experimentally in a lab-scale wind turbine. It is demonstrated that the wind turbine presents more interaction at the transition zone. Then, this operational point is used as the nominal one for the controller designs. At this point, decoupling controllers obtain perfect decoupling while the H ∞ control presents important interaction in the generated power loop. On the other hand, they are slightly surpassed by the robust design at other points, where perfect decoupling is not achieved. However, decoupling controllers are easier to design and implement, and specifically dynamic simplified decoupling achieve the best global response. Then, it is concluded that the proposed methodologies can be considered for implantation in industrial wind turbines to improve their performance.

Wind energy conversion systems are very challenging from the control system viewpoint. The control difficulties are even more challenging when wind turbines are able to operate at variable speed and variable pitch. The contribution of this work is focused on designing a combined controller that significantly alleviates the wind transient loads in the power tracking and power regulation modes as well as in the transition zone. In a previous work, the authors studied the applicability of different multivariable decoupling methodologies. The methodologies were tested in simulation and verified experimentally in a lab-scale wind turbine. It was demonstrated that multivariable control strategies achieve a good closed-loop response within the transition region, where the interaction level is greater. Nevertheless, although such controllers showed an acceptable performance in the power tracking (region II) and power regulation (region IV) zones, appreciable improvement was possible. To this end, the new proposed methodology employs a multivariable gain-scheduling controller with a static decoupling network for the transition region and monovariable controllers for the power tracking and power regulation regions. To make the transition between regions smoother, a gain scheduling block is incorporated into the multivariable controller. The proposed controller is experimentally compared with a standard switched controller in the lab-scale wind turbine. The experiments carried out suggest that the combination of the proposed multivariable strategy for the transition region to mitigate wind transient loads combined with two monovariable controllers, one dedicated to region II and other to region IV, provide better results than traditional switched control strategies.

Wind turbines systems considered multivariable processes can work in several operational modes. Each mode can be represented with a dynamic model. This fact supposes a difficulty in controlling these types of systems. In addition, the models are subjected undesired interactions between variables. In this paper, different multivariable methodologies are proposed to deal with the previous problems when they are applied to a variable-speed variable-pitch wind turbine. Specifically, the proposed methods to be performed and compared are a multivariable robust control based on the mixed sensitivity problem and multivariable control strategies with different decoupling networks.

This paper presents an interactive software tool to monitor in real-time thermal comfort in buildings. Specifically, the tool is used to estimate predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) indices, which are widely accepted in the framework of thermal comfort and recognized by international standards. In this work, the tool was tested in an office building with an HVAC system based on solar energy. To perform this task, a network architecture that enables communication between different protocols is proposed, with a TCP/IP-Modbus gateway and a web server as the main elements, providing in this way external connectivity and data collection from different sensors. The tool communicates remotely with the renewable system and proposes corrective control indications to maintain the indoorair conditions inside the optimal comfort range. Keywordsthermal comfort; distributed systems; interactive tool; renewable energy and sustainability.978-1-4799-9936-1/15/$31.00 ©2015 IEEE