Control system

This comprehensive article deals with the important field of control systems engineering education. Efforts have been made to present some historical perspectives, major concepts and thoughts on a practical curriculum when this field is viewed as a discipline. Also discussed are curricular issues including typical laboratory systems with emphasis on the role of simulation, logic and sequencing, and real-time simulation. An elaborate section is devoted to CACE software, its role in teaching and learning, potential shortfalls, and trends in software development and use. Views from industry are sought in terms of desirable skills in the practicing engineer and continuing education needs. A survey of a few academic programs and a complete list of textbooks in control over the past three decades appear in the appendices.

A straightforward approach for designing fuzzy logic based controllers in Matlab/Simulink environment is presented in this paper. The approach focuses on the fuzzy rule base construction using the time varying values of control error (e) and its change (∆e) mapped on e-∆e space. In order to show the generalized model simplicity of the proposed approach, a fuzzy logic controller (FLC) is designed in Matlab/Simulink environment. For validation, the generated FLC block is simulated to control five different systems such as a PMDC motor speed control system, a position control system, a radar tracking control system, a synchronous generator voltage control system, and loadfrequency control of a two-area power system. The simulation results obtained by FLC are also compared with the results obtained using PID controllers for applicability validation of the developed FLC block in Matlab/Simulink environment.

A new method for PID controller tuning based on process models for cascaded control systems is proposed in this paper. The method consists of first finding the ideal controller that gives the desired closed loop response and then finding the PID approximation of the ideal controller by Maclaurin series. This method can be applied to any open loop stable processes. Furthermore, it enables us to tune the PID controllers both for the inner loop and the outer loop simultaneously while existing tuning methods tune the inner loop first and the outer loop next. Closed loop responses of cascade control loops tuned by the proposed method are compared with those of existing methods such as the frequency response method and the ITAE method. The results show that the proposed tuning method is superior to the existing methods. Figure 11. Closed loop response due to set point change (C1/R1) for example 3.

This paper presents the influence of the solar radiation and ambient temperature variation on the performance of a stand alone photovoltaic pumping system which composed of a PV generator, DC-DC adaptor, DC-AC inverter and an immersed group motor-pump. Those performances such PV efficiency, inverter efficiency and flow rate are improved by a judicious control implanted on the converters. The maximal power point tracking (MPPT) control allows the extraction of the maximum output power delivered by the PV generator. However the inverter insures a pulse width modulation (PWM) control of the asynchronous motor and a sine wave form of output signals. We proceed to modelling the PV pumping system with power electronic converters allowing respectively optimal operating point tracking and power conversion under the appropriate command. From the obtained simulation results, under Matlab/Simulink environment, we will discuss how the ambient temperature and the solar radiation influence the performance of the PV plants. The experimental results of the PV pumping system installed in Tunisia (2.1 kWc) verify the validity of the model and the proposed controller. Résumé -Cet article présente l'influence de l'irradiation solaire et de la variation de la température ambiante sur les performances d'un système de pompage photovoltaïque composé d'un générateur photovoltaïque, d'un adaptateur DC-DC, d'un onduleur DC-AC et d'un groupe moteur-pompe immergé. Ces performances telles que le rendement photovoltaïque, le rendement de l'onduleur et le taux du débit, sont améliorées par un système de contrôle judicieux implanté sur les convertisseurs. Le système de contrôleur du point de puissance maximal (MPPT) permet l'extraction du maximum de la puissance de sortie délivrée par le générateur photovoltaïque. Mais l'onduleur assure le contrôle de la modulation de largeur d'impulsions (PWM) du moteur asynchrone et de la forme de l'onde sinusoïdale des signaux de sortie. Nous procédons à la modélisation du système de pompage photovoltaïque avec des convertisseurs électroniques de puissance permettant de suivre respectivement le point optimal de fonctionnement et le rendement de conversion dans le cadre de la commande appropriée. A partir des résultats de simulation obtenus dans l'environnement Matlab/Simulink, nous allons discuter de l'influence de la température ambiante et du rayonnement solaire sur le fonctionnement des centrales photovoltaïques. Les résultats expérimentaux du système de pompage photovoltaïque installé en Tunisie (2,1 kWc) permettent de vérifier la validité du modèle et du contrôleur proposé.