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The concept of using renewable energy sources usage is increasing day by day but there is a limitation of it as we cannot use standalone renewable system. With standalone systems, the storage devices are used for backup power. The load and sources are interfaced by the power converters. In this paper, a new three port converter is analyzed. The analyzed converter is derived from full bridge converter...
In this paper, an optimization of fuzzy logic controller (FLC) based maximum power point tracking (MPPT) using genetic algorithm (GA) is performed. The optimization process is performed by tuning the FLC's data base (DB) represented by parameters of membership functions (MFs) used. The tuning process is based on an objective function that is defined in terms of the statistic quantity named integral...
Due to the non-linearity of current-voltage of solar cell model, the conventional methods are incapable to extract the parameters of solar cell with high accuracy. The implicit nonlinear equation describing the single and double diodes solar cell in five and seven parameters is rewritten as optimization problems with constraint functions and it is solved by using a firefly algorithm optimization....
This paper presents three-port DC-DC converter modeling, its simulation and its control. The three port converter interfaces with the PV panel, bidirectional battery and load which is isolated by a transformer. There are two sources used in the three-port converter and the flow of power in the converter is controlled by switches (MOSFETs) on-off states. To obtain maximum power from the PV panel, a...
This paper proposes an intelligent maximum power point tracking (MPPT) strategy based on the combination of fuzzy logic control (FLC) and artificial neural network (ANN) to improve the power output performances of PV system. Firstly, under various weather conditions, ANN is trained to estimate the optimal MPP voltage (Vmpp) of the PV module. Then, this trained ANN is used as a fundamental stage to...
The current-voltage characteristics of photovoltaic module are non-linear, multivariable and multi-modal and difficult to optimize the electrical intrinsic parameters. The conventional methods are incapable to optimize the parameters of photovoltaic module with high accuracy. Recently, the bio-inspired algorithm such as firefly algorithm has attracted the intention to optimize the non-linear and complex...
This paper makes a comparison between two control methods for maximum power point tracking (MPPT) of a photovoltaic (PV) system under varying irradiation and temperature conditions: the fuzzy logic and the neural network control. Both techniques have been simulated and analyzed by using Matlab/Simulink software. The power transitions at varying irradiation and temperature conditions have been simulated...
In this paper, two maximum power point tracking (MPPT) algorithms in a photovoltaic electrical energy generation system are analyzed and compared. The Matlab/Simulink is used to establish the model of a photovoltaic system with MPPT function. This system is developed by combining the models of established solar module and DC-DC boost converter with the algorithms of hill climbing (HC) and artificial...
Due to the non-linearity, multivariable and multimodal features of current-voltage of solar cell models, the conventional methods are incapable to estimating the parameters of solar cell with high accuracy. Recently, the bio-inspired algorithms have attracted the attention. The firefly algorithm is nature-inspired stochastic optimization algorithm is among the most powerful algorithms in solving modern...
The objective of this work was to use Box — Wilson experimental plan to establish the relation between a dependent variables P (the delivered power) and three independent variables X1 (current density), X2 (air pressure) and X3 (air stoichiometry) in order to obtain the optimal values of the independent variables which give the maximum values of the fuel cell electric delivered power. The development...
Smart Grids is already considered an attractive topic in the power engineering education programs. Politehnica University of Bucharest has a unique profile in the engineering higher education landscape by including among its 14 Faculties, one dedicated to Power Engineering and another one to Electrical Engineering. In this paper we focus on the smart grids topics that the students enrolled in non-power...
Voltage unbalance is a common phenomenon in AC power network. This disturbance can bring to the three-phase induction motors connected to the power supply system important drawbacks such as overheating, drop of efficiency and reduction in output torque. Therefore, operation of an induction motor with voltage unbalance above 5% is not recommended and therefore continuous monitoring of voltage unbalance...
This article presents the performance analysis of a conventional hybrid photovoltaic/thermal air heating collector. An excel spreadsheet is developed and various parameters are calculated for single-glass configuration. Results are presented to show the effect of various design and operational parameters on the performance of a system. These results are useful for designing such systems more scientifically.
Voltage unbalance is a common phenomenon in AC power network. This disturbance can cause on the three-phase induction motors connected to the power supply system serious ill effects such as overheating, drop of efficiency and reduction in output torque. Therefore, operation of an induction motor for any length of time above 5% of voltage-unbalance condition is not recommended and on-line voltage unbalance...
Electrical contact resistance between bipolar plates of PEM fuel cells has attracted much attention since it is one significant part of the total contact resistance which plays an important role in fuel cell performance. The effect of contact pressure on the bipolar plates electrical contact resistance is discussed in this paper. Various roughness on the bulk surface and various ingredient percentages...
This paper presents a Stockwell transform-based method for processing starting angular speed data from an induction motor and transforming it into some forms that are useful for fault detection and diagnostics of rotor broken bars. The proposed method generates angular speed frequency-time spectrum that is dependent to the number of rotor broken bars and of the motor load level. The angular speed...
We point out versions of a well-known theorem of R. Datko for nonuniform exponential contractions. More precisely, we obtain theorems that characterize the nonuniform exponential stability and the nonuniform exponential dichotomy for nonuniform exponential contractions. Thus, we generalize the results in Datko (1972) [8] and Preda and Megan (1985) [14].
This paper presents the results of an investigation into suitable torque control schemes for an electric vehicle application. The electric vehicle drive consists of rewound induction motors and a three-level IGBT inverter switching at 10 kHz. The schemes investigated are Direct Torque Control DTC with three-level IGBT inverter, and a new direct-torque fuzzy control (DTFC) scheme of induction motor...
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