• Energy Research

En este artículo se propone una técnica alternativa de control lineal para maximizar la energía eólica capturada en una turbina eólica de eje horizontal. La estrategia propuesta se basa en técnicas de control proporcional integral generalizado (GPI) soportadas bajo el enfoque del rechazo activo de perturbaciones, que permite seguir de forma asintótica una trayectoria de referencia óptima de la velocidad del rotor sin el conocimiento exacto del modelo de la turbina eólica. La maximización de captura de energía se centra en mantener la velocidad específica de la turbina en su valor óptimo, por medio del control de la velocidad del rotor sobre una trayectoria óptima, en el cual el coeficiente de potencia es máximo. La metodología propuesta es validada mediante simulación usando una turbina eólica de 4,8 MW y comparada con una estrategia de control de par estándar. Los resultados muestran que las estrategias GPI propuestas son efectivas en términos de robustez y captura de energía. This paper proposes an alternative linear control technique to maximize the energy capture in a horizontal-axis wind turbine. The proposed strategy is based on Generalized Proportional Integral (GPI) controllers supported by the active disturbance rejection approach, which allows asymptotic tracking of a rotor speed reference trajectory without exact wind turbine model knowledge. The proposed methodology controls the tip-speed ratio, via the rotor angular speed, to an optimum point at which power ci! coefficient is maximum. Several simulations are performed on a 4.8MW wind turbine benchmark model in order to validate the proposed control strategy and to compare it to a classical controller. The simulation results show that the proposed control strategies are effective in terms of power capture and robustness.

An optimal control approach for a wind turbine drivetrain with a variable ratio gearbox is presented. The objective is to find the optimum shifting sequence of the variable ratio gearbox in order to maximize power generation and extend gear life. The employment of a variable ratio gearbox enhances the capabilities of the wind turbine to cope with wind speed variations. Based on the authors' preliminary study, the gear ratios of the variable ratio gearbox were carefully selected to maximize the wind energy capture. In this paper, a new control approach is proposed to achieve both extended gear service life and optimal energy harvesting. This new approach finds the gear shifting sequence that will minimize the tangential force on the gear tooth while maximizing the wind energy capture. The wind turbine drivetrain with a variable ratio gearbox is modeled and simulation results based on recorded wind data of different wind classes are presented and compared.

Abstract An efficient solar cooker has been designed, developed and tested. The device can be used for cooking, boiling and roasting of different foods in clear days. The important part of this new device is its stationary mode and maximum capture of energy through improved design and optimum tilt of the system. This new cooker has been found to be more practical in comparison to the simple hot-box type solar cooker, where one needs to direct it to follow the sun. The cooking trial shows that the new device can be used twice a day, even in winter days.

This paper proposes a control strategy to maximize the wind energy captured in a variable speed wind turbine, with an internal induction generator, at low to medium wind speeds. The proposed strategy controls the tip-speed ratio, via the rotor angular speed, to an optimum point at which the efficiency constant (or power coefficient) is maximum for a particular blade pitch angle and wind speed. This control method allows for aerodynamic rotor power maximization without exact wind turbine model knowledge. Representative numerical results demonstrate that the wind turbine can be controlled to achieve near maximum energy capture.

This paper proposes an alternative robust observer-based linear control technique to maximize energy capture in a 4.8MW horizontal-axis variable-speed wind turbine. The proposed strategy uses a generalized proportional integral (GPI) observer to reconstruct the aerodynamic torque in order to obtain a generator speed optimal trajectory. Then, a robust GPI observer-based controller supported by an active disturbance rejection (ADR) approach allows asymptotic tracking of the generator speed optimal trajectory.The proposed methodology controls the power coefficient, via the generator angular speed, towards an optimum point at which power coefficient ismaximum. Several simulations (including an actuator fault) are performed on a 4.8MWwind turbine benchmark model in order to validate the proposed control strategy and to compare it to a classical controller. Simulation and validation results show that the proposed control strategy is effective in terms of power capture and robustness. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down.