Adaptive variable structure control law for a variable speed wind turbine

Presentado en el 13th WSEAS International Conference on Automatic Control, Modelling and Simulation, ACMOS'11

Robust speed control for a variable speed wind turbine

Modern wind turbines are designed in order to work in variable speed opera-tions. To perform this task, these turbines are provided with adjustable speed generators, like the double feed induction generator (DFIG). One of the main advantages of adjustable speed generators is improving the system efficiency compared with _xed speed generators, because turbine speed can be adjusted as a function of wind speed in order to maximize the output power. However, this system requires a suitable speed controller in order to track the optimal reference speed of the wind turbine. In this work, a sliding mode control for variable speed wind turbines is proposed. The proposed design also uses the vector oriented control theory in order to simplify the DFIG dynamical equations. The stability analysis of the proposed controller has been carried out under wind variations and pa-rameter uncertainties using the Lyapunov stability theory. Finally, the simulated results show on the one hand that the proposed controller provides a high-performance dynamic behavior, and on the other hand that this scheme is robust with respect to parameter uncertainties and wind speed variations, which usually appear in real systems.

Sliding mode control strategy for variable speed wind turbines

EFTA 2009

Sliding mode control law for a variable speedwind turbine

Modern wind turbines are designed in order to work in variable speed operations. To perform this task, wind turbines are provided with adjustable speed generators, like the double feed induction generator. One of the main advantage of adjustable speed generators is improving the system efficiency compared to fixed speed generators, because turbine speed can be adjusted as a function of wind speed in order to maximize the output power. However this system requires a suitable speed controller in order to track the optimal reference speed of the wind turbine. In this work, a sliding mode control for variable speed wind turbines is proposed. An integral sliding surface is used, because the integral term avoids the use of the acceleration signal, which reduces the high frequency components in the sliding variable. The proposed design also uses the vector oriented control theory in order to simplify the generator dynamical equations. The stability analysis of the proposed controller has been carried out under wind variations and parameter uncertainties by using the Lyapunov stability theory. Finally simulated results show, on the one hand that the proposed controller provides a high-performance dynamic behavior, and on the other hand that this scheme is robust with respect to parameter uncertainties and wind speed variations, that usually appear in real systems.

Variable structure control for maximum wind power extraction

EuroPES 2009

Análisis de prestaciones de variador de frecuencia Sinamics para el control de velocidad y posición.

[ES]En este documento se exponen los resultados de las diferentes funcionalidades analizadas del variador de frecuencia Sinamics G120. El dispositivo se ha configurado mediante el software de control TIA Portal para la realización de tareas de control de velocidad de un motor de inducción, así como el control de posición del eje del motor y de un eje lineal acoplado al mismo.

Sliding Mode Control Strategy for Wind Turbine Power Maximization

The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, a sliding mode control for variable speed wind turbine that incorporates a doubly fed induction generator is described. The electrical system incorporates a wound rotor induction machine with back-to-back three phase power converter bridges between its rotor and the grid. In the presented design the so-called vector control theory is applied, in order to simplify the electrical equations. The proposed control scheme uses stator flux-oriented vector control for the rotor side converter bridge control and grid voltage vector control for the grid side converter bridge control. The stability analysis of the proposed sliding mode controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand, that the proposed controller provides high-performance dynamic characteristics, and on the other hand, that this scheme is robust with respect to the uncertainties that usually appear in the real systems.

An adaptive sliding mode control law for the power maximization of the wind turbine system

POWERENG 2011

A Real-Time Sliding Mode Control for a Wind Energy System Based on a Doubly Fed Induction Generator

In this paper, a real time sliding mode control scheme for a variable speed wind turbine that incorporates a doubly feed induction generator is described. In this design, the so-called vector control theory is applied, in order to simplify the system electrical equations. The proposed control scheme involves a low computational cost and therefore can be implemented in real-time applications using a low cost Digital Signal Processor (DSP). The stability analysis of the proposed sliding mode controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. A new experimental platform has been designed and constructed in order to analyze the real-time performance of the proposed controller in a real system. Finally, the experimental validation carried out in the experimental platform shows; on the one hand that the proposed controller provides high-performance dynamic characteristics, and on the other hand that this scheme is robust with respect to the uncertainties that usually appear in the real systems.

Effective and Robust Generalized Predictive Speed Control of Induction Motor

14 p.

Pitch Based Wind Turbine Intelligent Speed Setpoint Adjustment Algorithms

This work is aimed at optimizing the wind turbine rotor speed setpoint algorithm. Several intelligent adjustment strategies have been investigated in order to improve a reward function that takes into account the power captured from the wind and the turbine speed error. After different approaches including Reinforcement Learning, the best results were obtained using a Particle Swarm Optimization (PSO)-based wind turbine speed setpoint algorithm. A reward improvement of up to 10.67% has been achieved using PSO compared to a constant approach and 0.48% compared to a conventional approach. We conclude that the pitch angle is the most adequate input variable for the turbine speed setpoint algorithm compared to others such as rotor speed, or rotor angular acceleration.

Factores determinantes de la integración de la variable medio ambiente en los planteamientos de la economía de la empresa y el marketing

[ES] Actualmente las empresas se enfrentan a un nuevo reto: la integración de los aspectos medioambientales en la gestión y toma de decisiones empresariales. Varios han sido los factores desencadenantes, que han inducido a la Economía de la Empresa y al Marketing a introducir la variable medio ambiente en sus planteamientos, en aras a conformar una base teórica sistematizada que permita abordar con éxito las necesidades medioambientales de la clientela y de la sociedad. En este trabajo se analizan los factores que han contribuido a incrementar la importancia de la variable medio ambiente en la empresa, así como las causas que, en su día, motivaron su exclusión.

El compromiso como variable mediadora para la predicción de las futuras intenciones de consumo en los servicios. Una aproximación empírica a los consumidores de artes escénicas en España

[ES] El presente trabajo de investigación trata de arrojar luz sobre las relaciones entre las variables Satisfacción, Compromiso, Confianza y Futuras Intenciones de compra. Con este fin, se propone un Modelo de Gestión de las Relaciones con Clientes de Servicios en el que se observa que la variable más importante en la consecución de resultados positivos en lo que respecta a intenciones de asistencia futura de los consumidores es el Compromiso.

An Estimated New-Keynesian Model with Unemployment as Excess Supply of Labor

Wage stickiness is incorporated to a New-Keynesian model with variable capital to drive endogenous unemployment uctuations de ned as the log di¤erence between aggregate labor supply and aggregate labor demand. We estimated such model using Bayesian econometric techniques and quarterly U.S. data. The second-moment statistics of the unemployment rate in the model give a good t to those observed in U.S. data. Our results also show that wage-push shocks, demand shifts and monetary policy shocks are the three major determinants of unemployment fl uctuations. Compared to an estimated New-Keynesian model without unemployment (Smets and Wouters, 2007): wage stickiness is higher, labor supply elasticity is lower, the slope of the New-Keynesian Phillips curve is flatter, and the importance of technology innovations on output variability increases.

Factores explicativos de la intención de emprender en la mujer. Aspectos diferenciales en la población universitaria según la variable género

El objetivo del presente trabajo de investigación es arrojar luz sobre los factores que explican la menor intencionalidad en la población femenina para involucrarse en procesos de creación de empresas. Para ello, se ha desarrollado un modelo de ecuaciones estructurales que identifica un conjunto de variables que permiten explicar la intención de emprender en la población potencialmente emprendedora. La validación del modelo se ha realizado mediante una encuesta realizada a 1222 estudiantes de 12 titulaciones diferentes de la Universidad de Málaga. La aplicación del modelo a las poblaciones masculina y femenina ha permitido apreciar diferencias significativas en los patrones de comportamiento en función del género, identificando un proceso más complejo y necesitado de apoyo externo en la población femenina con respecto a la masculina.