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[Resumen] En los últimos años, la industria de producción de microalgas ha tenido una gran repercusión debido a su utilidad para la mitigación de los gases de efecto invernadero, tratamiento de residuos, producción de biocombustible, industria de cosméticos, y alimentación animal y humana. Sin embargo, la dinámica de estos sistemas es muy compleja y no lineal por lo que se requieren tanto modelos como estrategias de control avanzadas. En este trabajo se ha propuesto un control reseteado para el pH de un fotobiorreactor industrial raceway que mejora el comportamiento del sistema con respecto a otros controladores lineales., [Abstract] In recent years, the microalgae production industry has had a major impact due to its usefulness in mitigation of greenhouse gases, waste treatment, biofuel production, cosmetics industry, and animal and human food. However, the dynamics of these systems is very complex and non-linear, so both models and advanced control strategies are required. In this work, a reset control has been proposed for the pH variable in a raceway industrial photobioreactor that improves the behavior of the system with respect to other linear controllers.

[Resumen] Los reactores de microalgas proporcionan una alternativa eficiente y limpia para la producción de biogas, biofuel, productos nutricionales y cosm´eticos, etc. El principal objetivo de control en estos sistemas es la optimización de la productividad, por lo que resulta crucial la monitorización de la concentración de biomasa en el reactor para determinarla en tiempo real. Pese a ello, no existen en el mercado soluciones suficientemente robustas, en especial para los reactores abiertos a escala industrial. En este trabajo se presentan unos primeros resultados en el desarrollo de un nuevo estimador de biomasa en línea, basado en un observador muy robusto, el de modos deslizantes, combinado con un modelo dinámico no lineal y variante en el tiempo dotado de un número mínimo de estados, que permiten capturar los aspectos esenciales del proceso de producción de microalgas. El observador se ha testado con un modelo completo del reactor y las simulaciones muestran resultados prometedores en términos de precisión y robustez., [Abstract] Microalgae reactors provide an efficient and clean alternative for production of biogas, biofuel, nutritional and cosmetic products, etc. The main control objective in these systems is the optimization of productivity. For this reason, it is crucial monitoring the biomass concentration in the reactor and so to determine the productivity in real time. Despite this, there are no sufficiently robust solutions on the market, especially for open reactors on an industrial scale. This paper presents the first results in the development of a new online biomass estimator, based on a very robust observer, the sliding modes observer , combined with a nonlinear and time-varying dynamic model endowed with a minimum number of states, which allow capturing the essential aspects of the microalgae production process. This soft-sensor has been tested with a complete model of the reactor and the simulations show promising results in terms of accuracy and robustness.

Power converters in grid connected systems are required to have fast response to ensure the stability of the system. The standard PI controllers used in most power converters are capable of fast response but with significant overshoot. In this paper a hybrid control technique for power converter using a reset PI + CI controller is proposed. The PI + CI controller can overcome the limitation of its linear counterpart (PI) and ensure a fast flat response for power converter. The design, stability and cost of feedback analysis for a DC-DC boost converter employing a PI + CI controller is explored in this work. The simulation and experimental results which confirm the fast, flat response will be presented and discussed.

Hybrid controllers are capable of improved performance over their linear counterparts. In particular, reset controllers like the PI+CI are capable of fast flat response for lag dominant plants. Grid connected power converters especially interfacing energy storage systems to grids are required to have fast response to varying load demands to ensure minimum variation in grid parameters. Application of PI+CI controllers in such systems can improve their performance. In this work the improvement brought about by use of PI+CI controller employed for energy storage system power converters is highlighted by comparing it with PI controller based system under load variations. A DC microgrid with Fuel cell-supercapacitor based storage elements are considered here. The design criteria and simulation results are presented here.

The goal of this work is to apply the framework of reset systems, in particular PI+CI controllers, in the controller design for power converters. While the PI+CI controller has been applied in several industrial applications, the application of such controllers in fast electrical systems especially power electronic converters appears to be new. The main motivations for this proposal are performance superiority of these controllers and the ability to produce a fast flat response without any overshoot for a step input. Another factor that influenced the use of such controller is the relatively simple design equations, which enables plug and play capability. The flat responses are highly interesting from the perspective of power converters especially when they are connected to power grids.