Cem Onat

Fractional controller design for suppressing smart beam vibrations

Purpose – The purpose of this paper is to detail the design of a fractional controller which was developed for the suppression of the flexural vibrations of the first mode of a smart beam.Design/methodology/approach – During the design of the fractional controller, in addition to the classical control parameters such as the controller gain and the bandwidth; the order of the derivative effect was also included as another design parameter. The controller was then designed by considering the closed loop frequency responses of different fractional orders of Continued Fraction Expansion (CFE) method.Findings – The first, second, third and fourth order approximations of CFE method were studied for the performance analysis of the controller. It was determined that the increase in the order resulted in better vibration level suppression at the resonance. The robustness analysis of the developed controllers was also conducted.Practical implications – The experimentally obtained free and forced vibration results i...

WGC Based Robust and Gain Scheduling PI Controller Design for Condensing Boilers

This paper addresses the water temperature PI control in condensing domestic boilers. The main challenge of this process under the controller design perspective is the fact that the dynamics of condensing boilers are strongly affected by the demanded water flow rate. First, a robust PI controller based on weighted geometrical center method is designed that stabilizes and achieves good performance for closed-loop system for a wide range of the water flow rate. Then, it is shown that if the water flow rate information is used to update the controller gains, through a technique known as gain scheduled control, the performance can be significantly improved. Important characteristics of these PI design approaches are that the resulting parameters are calculated numerically without using any graphical method or iterative optimization process and that it guarantees the stability of the closed-loop. Significantly, simulation results have demonstrated that the proposed tuning techniques can perform better for set point changes and load disturbance than other available methods in the literature.

A Practical PI Tuning Approach For Time Delay Systems

Abstract In this paper, a simple PI tuning method for time delay systems is proposed. The main characterization of the method is first to obtain the stability region in the ( k p , k i )-plane using the stability boundary locus method and then to find the weighted geometrical center point of this region through its stability boundaries. Finally, this center point of the stability region in the ( k p , k i )-plane gives the tuning parameters for the PI controller. The proposed method gives a simple and reliable result which is illustrated by several examples, and hence is practically useful for the designers in the analysis and control of time delay systems.

A new tuning method for PI λ D μ controller

The paper presents development of a new tuning method for fractional order PID controller for the systems which have integer order transfer functions. All the parameters of the controller, namely proportional gain kp, integral gain ki, derivative gain kd, fractional order of integrator λ and fractional order of differentiator μ can be obtained by using this method. It is clearly shown that the fractional order controller, which the parameters obtained by the proposed method, gives better response than the integer order one for the same system.

An Investigation on the Economic Analysis of Wind Turbines

Wind energy, one of the renewable energy sources, has now become a global power generation industry competing with other sources of energy generation. While the interest and investments for wind energy recycling systems are gradually increasing worldwide, both the scientific studies and commercial activities in this field in Turkey are expanding everyday. In this study, some economic subjects related with the energy obtained by wind turbines have examined and the effects of blade number and attack angle on annual maximum energy production obtained from the wind turbines having 4415 NACA and LS- 1 blade profiles, which are planned to erect in Malatya city, Turkey, have analyzed.

Wind Energy Potential of Southeast Anatolia Region of Turkey and an Optimum Wind Turbine Propeller Design for Siverek

Continuing to use fossil fuels is bound to pollute the atmosphere, and consequently, unwanted greenhouse and climate change effects will come to dominate every part of the earth. It is, therefore, advisable to exploit clean energy resources for many nations in the world to try to keep their environment friendly, such as wind energy. Hence, it is necessary to determine to start the immediate usage of the wind energy potential and the investigation of the necessary techniques and economic feasibility in every country. In this study, the wind energy potentials of Turkey and its Southeast Anatolia region were investigated and an optimum horizontal-axis wind turbine propeller was designed by using 144 different design parameters for NACA 4415 and LS-1 blade profiles and then the possible maximum electrical energy per year generated by the wind was also calculated by using meteorological data for Siverek.