ملخص البحث :

The induction motors run only at their rated speed when it is connected to the supply, many applications in need of adjustable speed operations. Controlling the induction motor speed efficiently is a main concern nowadays. With the fast advancement in the semiconductor manufacturing technology, the size and price of the semiconductors went down drastically. And this lead to that the motor user can exchange the ineffiecient mechanical motor drive with the inverter. This paper presents the necessity of induction motors speed control. Out of various methods of speed control of induction motors, method of V/f speed control prove to be the most multilateral. The scheme of implementing V/f speed control presented. The inverter is one of basic requirements for induction motor speed control by V/f method, the inverter traditional control methods is modulated using Arduino Uno which control the whole operation of the proposed scheme, a good control of V/f ratio and smooth speed control been conducted from the scheme, the cost of the modulated scheme is less, the code is easy and can be updated easily to get different results, the scheme can be upgraded to be controlled from distant areas.

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This paper proposes a simulation of Photovoltaic energy used to supply an induction motor with a comparison of two types of inverters. In general, the greater number of motors which"are used in commercial and industrial applications are"induction motors. To use PV source to run the induction motor, an interface circuits are used which are a dc-dc"converter and an inverter, the PV cell has nonlinear behavior,"a dc-dc converter is used along with Maximum Power Point Tracker controller to improve the efficiency by boosting the output voltage of the PV module and to match the load demand."The dc output voltage of PV module then"converted to AC, two types of inverter are presented, A conventional Voltage Source Inverter system and multilevel inverter system which employ selective harmonic elimination method fed three phase induction motor, these two types of inverters are simulated using Matlab/Simulink and their results are presented. The FFT spectrum is presented of the output currents to analyze the harmonics reduction, which shows that the"multilevel inverter is better than VSI system"according to harmonics reduction and increment in output voltage and power.

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A new prediction modelling approach for hydropower generation in the presence of input random variables is investigated in this paper. Firstly, they decomposed the annual input variables like the net head of the turbine, and flow rate of water into a certain number of detail signals through artificial neural network (ANN) transform. ANN model used to predict the annual power generation. After the stationary simulation prediction model is obtained, the prediction results were superposed. Finally, simulation results have demonstrated the robustness and effectiveness of this new approach when compared with the existing one.

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Theoretically, several self-tuning control (STC) algorithms have been developed and many simulation results have proved their feasibility in the past years, but applications of STC are hardly seen. This paper proposes direct and indirect STC plans that can be applied to a chemical process system with a time delay auto-regressive and exogenous model of a varied time constant. The plan controller is a combination of a generalized minimum variance control (GMVC) strategy and an identification algorithm (simplified parameter) called recursive least squares to estimate controller parameters for the direct method and plan parameters for the indirect method. The experimental results show that GMVC is able to track the desired input or set point.

ملخص البحث :

This paper represents an innovative algorithm to estimate optimum placement of Distribution Static Synchronous Compensator (D-STATCOM) in the multi-machine atmosphere. The main reason for the substantial loss of power in distribution devices is the voltage drop across the device. This shows that by increasing the voltage profile of the distributed device the entire loss of power is decreased. D-STATCOM was designed for satisfactory dynamic response and the control gains were normally tuned for trial-and-error method. The problem of tuning the D-STATCOM parameter is transformed into an optimization problem this is resolved by hybrid bacteria foraging and gray wolf optimization algorithm (HBF-GWO). Load flow analysis (LFA) is utilized for calculating the reactive power, voltage profile and active power in distributed systems. Also, IEEE 30-bus radial distribution devices are utilized to check this system. Performance of the proposed HBF-GWO algorithm with D-STATCOM is matched with a Genetic Algorithm (GA) with D-STATCOM under several operating conditions and instabilities.

ملخص البحث :

Today, power systems are being operated under greatly stressed conditions due to rapidly growing demand for electrical energy, penetration of renewable energy sources, large seasonal load variations, and operation in competitive energy market conditions. The main part of this work involves achieving complete system observability and improving voltage stability level simultaneously by placing a minimal number of PMUs. Initially, weak buses (very sensitive to smaller reactive power variations) are identified by using Fast Voltage Stability Index (FVSI) calculation. In this work, the reliability of observing the weak buses is purposely maximized. Suppose any sudden voltage instability problem occurs on the weak bus. In that case, PMUs can immediately communicate to the operator and prevent the outage of the weak bus, even if one of the PMUs fails. PMUs can maintain the FVSI value of the critical lines, not exceeding their maximum limit, by initiating the remedial actions scheme, such as smart islanding, controlling the transformer tap settings, coordinating between automatic corrective devices, etc. In this system, the positioning of PMUs on poor buses should be favoured over other buses. Improved voltage reliability can be accomplished by effective and accurate control of critical lines and vulnerable buses. This is done by a small rise in the amount of PMUs relative to previous results.