Issam Salhi

Induction motor speed drive improvement using fuzzy IP-self-tuning controller. A real time implementation

An IP-self-tuning controller tuned by a fuzzy adjustor, is proposed to improve induction machine speed control. The interest of such controller is the possibility to adjust only one gain, instead of two gains for the case of the PI-self-tuning controllers commonly used in the literature. This paper presents simulation and experimental results. These latter were obtained by practical implementation on a DSPace 1104 board of three different speed controllers (the classical IP, the fuzzy-like-PI and the IP-self-tuning), for a 1.5KW induction machine. The paper presents different tests used to compare the performances of the proposed controller to the two others in terms of computation time, tracking performances and disturbances rejection.

Modeling and regulation of a micro hydroelectric power plant

Hydropower is emerging as a major contributor to the world energy requirement. Itpsilas inexhaustible, clean and has many other benefits as it doesnpsilat encounter the problems of population displacement and environmental problems. However, it requires control systems to keep the frequency values constant. In this paper we develop a mathematical model for a micro hydroelectric power plant (MHPP). We validate this model by analysing a MHPP prototypepsilas performances. The prototype is installed in our laboratory. We use the downstream regulation which ensures good frequency regulation results. The used controller is the dasiaPIpsila one. The practical results obtained are similar for those in simulation.

IM Direct Torque Control with no flux distortion and no static torque error

The purpose of this paper is to improve DTC control strategy performances. In fact, we propose controlling both stator flux components (real and imaginary) through two hysteresis controllers. Thus, a new switching table which is independent from sector determination, and does not introduce zero voltage vectors is established; with much reduced size when compared to Takahashis one. The proposed strategy has allowed cutting off with flux and current harmonics related to distortion caused by sector exchanges. Also, we provide theoretical evidence about the existence of static torque error in classical DTC, and propose a simple PI-type controller to cancel it. The proposed strategy is validated by simulation and practically on a DSPace 1104 board, for a 1.5 (kW) induction motor and various torque references.

Modeling a three-phase micro hydropower plant prototype using Takagi-Sugeno fuzzy approach

This paper presents a Takagi-Sugeno (TS) fuzzy model of a three-phase micro hydropower plant (MHPP) prototype. It represents the system as an interpolation between local models. Each local model is linear system validated around an operating point. The Three-phase MHPP behavior varies with load variations and water flows. These matters create difficulties to have an exact model close to real system. This paper proposes a multi-model approach for modeling the overall behavior of the three-phase MHPP based on the identification of a simple approximation of first and second order systems around several operating points (different water flows and load variations). The results show that the approximation results of second order system have high accordance with the real system responses. This approximation offers more opportunities to synthesize suitable robust controllers for MHPP based on digital calculators, especially when the proposed approach is used in closed loop. Besides, the paper also presents a new load-frequency structure for three-phase MHPP. This structure is controlled by a simple Proportional Integral (PI) controller. The developed TS fuzzy models were experimentally validated taking into consideration various working conditions.

Thermal efficiency and exergy enhancement of solar air heaters, comparative study and experimental investigation

This paper links the geometric design of most classical configurations of solar air heaters (SAHs), their thermal performances, and their appropriate application. The optimization concerns mainly the absorber shape and the airflow direction. Therefore, single pass and counter flow double pass SAHs with flat plate, finned, and V-corrugated absorbers and SAH with an external recycle were investigated. The overall aim is to single out the most suitable configurations for the drying process and habitation heating. Modeling of the SAHs was based on solving the energy balance equations of the SAHs components. The numerical results showed that the thermal efficiency was significantly improved by the counter flow double pass mode by about 17.01% for SAHs with a flat plate absorber and 9.03% for SAHs with a V-corrugated absorber. Furthermore, the V-corrugated shape of the absorber increases the thermal and exergy efficiencies compared to the flat plate shape, e.g., by 8.66% and 1.27% at m = 0.025 kg s−1, respectively. In addition, the present study highlighted that the outlet air temperature and the thermal and exergy efficiencies could be enhanced by increasing the number of fins, and the optimal number of fins was found to be 24 per meter width of the SAH. Experimental studies were carried on a modular SAH. They showed the good capability of the developed model in predicting the thermal performances of the studied solar collectors. Finally, the SAHs were assigned to three appropriate uses, namely, aromatic and medicinal plant drying, agri-food product drying, and habitat heating.This paper links the geometric design of most classical configurations of solar air heaters (SAHs), their thermal performances, and their appropriate application. The optimization concerns mainly the absorber shape and the airflow direction. Therefore, single pass and counter flow double pass SAHs with flat plate, finned, and V-corrugated absorbers and SAH with an external recycle were investigated. The overall aim is to single out the most suitable configurations for the drying process and habitation heating. Modeling of the SAHs was based on solving the energy balance equations of the SAHs components. The numerical results showed that the thermal efficiency was significantly improved by the counter flow double pass mode by about 17.01% for SAHs with a flat plate absorber and 9.03% for SAHs with a V-corrugated absorber. Furthermore, the V-corrugated shape of the absorber increases the thermal and exergy efficiencies compared to the flat plate shape, e.g., by 8.66% and 1.27% at m = 0.025 kg s−1, re...

Heat transfer in a solar-gas-electric hybrid dryer for the control of its operation and for energy management and storage

Transient CFD studies were performed on a designed dryer operated in natural convection in order to analyze the effect of thermal energy on the outlet. The dryer is equipped by an energy storage system by capture of heat in its sensitive form. Results show that by passing the air through rocks, it stores an amount of thermal energy which can be used in drying during the absence of solar radiation. A designed hybrid solar-gas-electric dryer was simulated on SolidWorks Flow Simulation, the temperature of the drying chamber could be regulated at every desired temperature, and this paper presents a case study of regulation of temperature at 60°C by modeling an on-off control on the gas and electric auxiliary heaters and on a cooling fan. The designed hybrid dryer is efficient since it regulates the air temperature of the drying chamber at desired values with optimal consumption of gas and electric energy compared to the energy received from sun.

Control of a solar dryer using a hybrid solar gas collector

Drying is one of the most energy intensive processes in agro product industry using solar energy appears as an attractive free and not polluting alternative to be used in drying processes. However the daily and seasonal fluctuations in the irradiation level requires using a solar-gas collector an auxiliary heating system to have a continuous drying process and allows the use of the solar dryer in unfavorable weather condition. A control system is essential to vary the gas flow in the injector by coordinating the control of a proportional valve, in order to maintain a suitable temperature in the drying cell. In this paper, an experimental study of solar dryer has been established under the solar irradiation of 935W/m2 and 1045W/m2. The maximum temperatures reached on the top of the collector and at drying chamber inlet were 81°C and 61 °C respectively. A polynomial approach is used to generate the solar dryer model, afterward; a PI controller has been implemented to ensure the monitoring of the gas valve for controlling the temperature in dryer cell related to the optimum temperature of each product.