Emre Dincel

A power system stabilizer design by big bang-big crunch algorithm

Power system stabilizers (PSSs) are used to enhance damping of electromechanical oscillations occurring in power systems after small or large disturbances. PSSs designed by classical control methods have been widely used to accomplish this task. In this study, a new method based on big bang-big crunch algorithm is proposed to optimize the parameters of PSSs with a conventional structure in order to stabilize the system and to increase damping of this type of oscillations. The success of the proposed method is demonstrated on a two-area test system through simulations in which both local and inter-area oscillations are effectively damped.

Guaranteed Dominant Pole Placement with Discrete-PID Controllers: A Modified Nyquist Plot Approach

Abstract Guaranteed dominant pole placement problem has already been considered in the literature (Journal of Process Control 19(2009):349–352). For the systems that are higher-order or have dead-time, pole placement procedure with PID controllers via modified Nyquist plot and root-locus has been proposed. Based on this idea, the dominant pole placement problem with discrete-PID controllers in z-domain is studied since it is important to take advantage of discrete-time domain representation during the pole placement procedure for time-delay systems. It is shown that modified Nyquist plot method is still valid in discrete-time domain and it is possible to find relevant discrete-PID controller parameters. Controller zeros are also considered in the study, since in the closed-loop controller zeros can disrupt the dominance. Success of the method demonstrated on example transfer functions.

Interlocking and Automatic Operating System Design with Automaton Method

Abstract Interlocking systems are one of the most important elements of railway signalization systems in order to ensure safe transportation. Software design of the interlocking systems can be performed by different methods such as automaton method, petri nets. These systems can be implemented by mechanical components or electronic devices such as Programmable Logic Controllers (PLCs). In this study, an interlocking system is designed by using automaton method for a sample railway simulator so that trains can move in a safe manner. In addition, in order to provide complete automatic operation, another system is also designed. Then both designed interlocking and automatic operation systems are implemented in Beckhoff CX1010 PLC and tested on simulator with the help of human interface that is created for this purpose.

A symbolic PI tuning method for first order systems with time delay

This paper presents a symbolic PI tuning method for first orders systems with time delay based on Pade approximation. The presented method is very easy to use like well-known methods such as Ziegler-Nichols and Cohen-Coon. Besides its easiness, the method performs a faster step response and no overshoot. Furthermore, it provides a good robust performance.

Modeling and control of under-damped second order systems with dead-time and inverse response

Systems with inverse response are difficult to be identified because of the existence of at least one zero at the right half s-plane. However, it is important to obtain the transfer function as accurately as possible for such systems to be able to provide the desired performance using a controller. If the system has dead-time, the design problem becomes more complicated. This paper presents a new modeling method for under-damped second order systems with an inverse response to overcome the difficulties both in the analysis and design. Besides, a PID controller design in discrete-time domain is also introduced to provide a good performance in the closed-loop. The performance of the proposed modeling and control technique is demonstrated on an example using simulations.

Digital PI-PD controller design for arbitrary order systems: Dominant pole placement approach

In this paper, a digital PI-PD controller design method is proposed for arbitrary order systems with or without time-delay to achieve desired transient response in the closed-loop via dominant pole placement approach. The digital PI-PD controller design problem is solved by converting the original problem to the digital PID controller design problem. Firstly, parametrization of the digital PID controllers which assign dominant poles to desired location is done. After that the subset of digital PID controller parameters in which the remaining poles are located away from the dominant pole pair is found via Chebyshev polynomials. The obtained PID controller parameters are then transformed into the PI-PD controller parameters by considering the closed-loop controller zero and the design is completed. Success of the proposed design method is firstly demonstrated on an example transfer function and compared with the well-known PID controller methods from the literature through simulations. After that the design method is implemented on the fan and plate laboratory system in a real environment.

Limitations on dominant pole pair selection with continuous PI and PID controllers

In the dominant pole placement approach, it is important non-dominant poles to be located far away from the dominant pole pair. Otherwise, predicting the closed-loop system transient response is difficult and satisfying the performance criteria becomes very challenging. It is known that PI and PID controllers are well-known and commonly used controllers in industrial applications. However, it is not possible to assign all of the closed-loop poles for higher order systems using such controllers because of the small number of controller parameters to be tuned. Therefore, the remaining poles may be located in the dominant region for a chosen dominant pole pair. In this study, it is aimed to find the limitations on dominant pole pair selection such that the unassigned poles can be located “m” times away from the design poles with PI and PID controllers. The success of the method is demonstrated on numerical examples.

Estimate of the farthest possible non-dominant pole locations with PID controllers

It is important to know how far non-dominant poles can be located away from the dominant poles since the closed-loop system transient response may not be as expected, if the non-dominant poles are not placed far enough from the dominant pole pair. Even if the arbitrary pole assignment is possible with a full state feedback or an output feedback controller with the order of plant order minus one, low order controllers and especially PID controllers are used in most practical applications. Therefore, the farthest possible non-dominant pole locations with PID controllers are found for all pole systems in this study. Proposed calculation method is demonstrated on two different examples and the closed-loop system performance is investigated with the designed PID controllers.

A new approach on angular position control of fan and plate system

In this paper, a linear control technique based on a PID controller, which is the most used controller type in the industrial applications, is proposed for the angular position control of fan and plate system that has a nonlinear characteristic. Although the system is nonlinear, in the experimental studies, it is observed that for any small region in which the system can be considered as linear, the system (the linear model obtained around an operating point) has the same characteristic in the all operating regions. A new control approach is proposed by using this property of the system to guarantee the stability and operation without any overshoot.