S. Hr. Aghay Kaboli

Rain-fall optimization algorithm: A population based algorithm for solving constrained optimization problems

Abstract This paper proposes rain-fall optimization algorithm (RFO), a new nature-inspired algorithm based on behavior of raindrops, for solving of real-valued numerical optimization problems. RFO has been developed from a motivation to find a simpler and more effective search algorithm to optimize multi-dimensional numerical test functions. It is effective in searching and finding an optimum solution from a large search domain within an acceptable CPU time. Statistical analysis compared the solution quality with well-known heuristic search methods. In addition, an economic dispatch (ED) optimization problem is run on an IEEE 30-bus test system, and the results, compared with those of recent optimization methods, show RFO performing relatively well, sufficiently effective to solve engineering problems. The constraint-handling strategy of the proposed method for solving ED problem is to generate and work with feasible solutions along all the optimization iterations without any mismatch between electricity demand and the total amount of power generation. Unlike the penalty methods, this strategy is unaffected by parameter setting of applied optimization method and its applicability for solving constrained optimization problems is not hampered. Eventually, its robustness is validated by the results of a sensitivity analysis of the parameters.

A 12-Sector Space Vector Switching Scheme for Performance Improvement of Matrix-Converter-Based DTC of IM Drive

This paper presents a direct torque control (DTC) switching scheme based on the direct matrix converter (DMC) using a 12-side polygonal space vector for variable speed control of an induction motor (IM). The conventional DTC scheme-based matrix converter (MC) is limited by 60° sectors of both flux and voltage vectors, which introduce a high torque ripple. The proposed method utilizes twelve 30° sectors of both flux and voltage vectors to increase the degrees of freedom for selection of proper vectors and reduce the torque ripple. The proposed switching scheme for the MC-based DTC of an IM drive select the appropriate switching vectors for control of torque with small variations of the stator flux within the hysteresis band. This improves the degrees of freedom in selecting the vector algorithm and the torque ripple as well. Furthermore, during the large torque demand, the probabilities of transgressing reference vector limits, which are enclosed by 12-side polygonal space vector, are reduced. Extensive simulation and experimental results are presented to verify the effectiveness of the 12-sector space vector switching scheme for the DTC of an IM fed by the DMC.

A PSO-DQ Current Control Scheme for Performance Enhancement of Z-Source Matrix Converter to Drive IM Fed by Abnormal Voltage

A rotational d–q current control scheme is prepared with the particle swarm optimization-PI controller, which drives an induction motor through an ultra-sparse Z-source matrix converter. To minimize the total size of the system, the lowest feasible values of Z-source elements are calculated by considering both timing and circuit aspects. A meta-heuristic method is integrated with the control system in order to find the optimum coefficients values in a single multimodal problem. Henceforth, the effect of all coefficients in minimizing the THD and balancing the stator current are considered simultaneously. By changing the reference point of magnitude or frequency, the modulation index can be automatically adjusted and respond to changes without heavy computational cost. The focus of this research is on having a reliable and lightweight system with no extensive computing time demand. The proposed scheme is validated by the promising simulation and experimental results.

Economic dispatch in a microgrid through an iterated-based algorithm

This paper presents a new algorithm to solve economic dispatch (ED) as an optimization problem in power systems. A simple iterated-based algorithm has been developed. It starts with a guess and converges to the optimal point in such a way that the total generation cost of a microgrid is minimized. Since microgrid is considered as a lossless small network, the algorithm is supposed to solve the lossless economic dispatch problem. The proposed method applied on a microgrid consisting of three distributed energy resources (DERs) with convex type of cost functions. The problem was also solved by CPLEX solver as a quadratic programming problem (QP) and the obtained results of proposed algorithm were compared with its results. The comparison confirmed the capability of proposed method to solve ED problem since it was easy to implement with acceptable speed and accuracy.

A hybrid Neuro-Fuzzy — P.I. speed controller for B.L.D.C. enriched with an integral steady state error eliminator

This paper is subject to present a hybrid Neuro-Fuzzy (N.F.) - P.I. fed Controller for controlling the speed of B.L.D.C. (Brush Less D.C.) motors to evolve the drives controlling performance at both transient and steady state conditions by considering a paralleled robust integral S.S.E.E. (Steady State Error Eliminator) to enrich the whole controlling process. In the presented hybrid system, P.I. N.F.C. is the main controller loop while the paralleled integral S.S.E.E. controller reimburses the steady state errors. The presented B.L.D.C. drive contains the capabilities of quick tracking, small steady state error and high stability despite of all load and parameter variations. MATLAB simulation results depict the impressiveness of the presented controlling system.

An iterated-based optimization method for economic dispatch in power system

This paper proposes an iterated-based algorithm to solve economic dispatch (ED) problem. The algorithm aims to determine the schedules of generating units in order to minimize the total generation cost. The problem is formulated mathematically as an optimization problem including objective function and constraints. Also the network loss as an important element for economic dispatch in power systems has been considered in the problem. The proposed method applied on 3-unit power system and the results were obtained and compared to classical and intelligent optimizations methods. The results clearly show that the proposed algorithm is capable of solving ED problem as well as other optimization methods.

A review of single phase power factor correction A.C.-D.C. converters

The demand for solid state A.C.-D.C. converters to enhance power quality in the expression of P.F.C. (Power Factor Correction) impels the proposal of miscellaneous topologies. These converters are expected to reduce the total harmonic distortion (T.H.D.) at A.C. input and accurately regulate D.C. output in Buck, Boost, Buck-Boost and multi-level models considering both unidirectional and bi-directional power flows. This paper presents an exhaustive review of I.P.Q.C.s (improved power quality converters) configurations, design features, and selection for specific. The paper is aimed to present a broad perspective on the status of I.P.Q.C. technology to researchers, designers and application engineers working on clean energy and smart grid fields.