지적-PID제어기를 이용한 발전기 AVR에 관한 연구

Abstract

Automatic voltage regulator(AVR) Automatic Voltage Regulator(AVR) is a device for obtaining constant and stable output voltage of the diesel power generator system. The role of AVR is to control the input voltage of the exciter of the generator in order to make the output voltage constant despite the presence of disturbances. Proportion-Integrative-Derivative (PID) controllers have been used as a main control system for AVR for power generator systems. As is well known, the structure of a PID controller is very simple, and it has only three parameters for tuning. This fact makes PID control easier to understand by the control engineers than other most advanced control techniques. In addition, the performance of a PID controller is satisfactory in most of the industrial applications. Because of the wide spread use of PID controllers it is interesting to have simple but efficient methods for tuning the controller. Since Ziegler and Nichols proposed their tuning rules, there have been lots of fantastic tuning methods as a result of active and intensive researches. However, if a time delay is existing in the plant, or in case of non-minimun phase system, it is not easy to determine appropriate PID parameters, and it is also need to readjust these parameters when there exists parameter variations in the plant. Recently, the model-free control methodology, which was proposed by M. Fliess and C. Join, has been widely successfully applied to many mechanical and electrical processes. The model-free and its corresponding “intelligent” PID(i-PID) controller provides good performances in disturbances rejection and an efficient robustness to the process internal changes. Recently, the model-free control methodology, which was proposed by M. Fliess and C. Join, has been widely successfully applied to many mechanical and electrical processes. The model-free and its corresponding “intelligent” PID(i-PID) controller provides good performances in disturbances rejection and an efficient robustness to the process internal changes. This paper is concerned with applicability of i-PID controller, which yields a controller that is continuously updated according to the dynamic changes of the whole system (including its load). This study is to improve output response characteristic of AVR for a power generator. That is, a new AVR system with i-PID is designed, and check its performance throughout the experiment using small real power generator under the situation of load changes. Before experiments, various simulations are carry out to confirm the response characteristics of AVR under the varying parameters of the plant. Then we compare the performance of 2-type of AVR, that is, the conventional PID and i-PID controller. The study check the output voltage fluctuation of the power generator: AVR with i-PID shows less fluctuation than that with the conventional PID. It is also confirmed that the transient response can be reduced by applying AVR with i-PID, and the steady-state response is especially improved when occurring parameter variations of the plant and varying its load. Finally, the output is not affected greatly by the chosen PID parameters.