POWER CONTROL AND OPTIMIZATION: Proceedings of the Second Global Conference on Power Control and Optimization
1159(2009); http://dx.doi.org/10.1063/1.3223952View Description Hide Description
Among the existing fuel cell technologies, Solid Oxide Fuel Cells (SOFC) are particularly suitable for both stationary and mobile applications, due to their high energy conversion efficiencies, modularity, high fuel flexibility, low emissions and noise. Moreover, the high working temperatures enable their use for efficient cogeneration applications.
SOFCs are entering in a pre‐industrial era and a strong interest for designing tools has growth in the last years. Optimal system configuration, components sizing, control and diagnostic system design require computational tools that meet the conflicting needs of accuracy, affordable computational time, limited experimental efforts and flexibility.
The paper gives an overview on control‐oriented modeling of SOFC at both single cell and stack level. Such an approach provides useful simulation tools for designing and controlling SOFC‐APUs destined to a wide application area, ranging from automotive to marine and airplane APUs.
1159(2009); http://dx.doi.org/10.1063/1.3223915View Description Hide Description
Some of the major limitations of renewable energy sources are represented by their low power density and intermittent nature, largely depending upon local site and unpredictable weather conditions. These problems concur to increase the unit costs of wind power, so limiting their diffusion. By coupling storage systems with a wind farm, some of the major limitations of wind power, such as a low power density and an unpredictable nature, can be overcome.
After an overview on storage systems, the Compressed Air Energy Storage (CAES) is analyzed, and the state of art on such systems is discussed. A Matlab/Simulink model of a hybrid power plant consisting of a wind farm coupled with CAES is then presented. The model has been successfully validated starting from the operating data of the McIntosh CAES Plant in Alabama. Time‐series neural network‐based wind speed forecasting are employed to determine the optimal daily operation strategy for the storage system. A detailed economic analysis has been carried out: investment and maintenance costs are estimated based on literature data, while operational costs and revenues are calculated according to energy market prices.
As shown in the paper, the knowledge of the expected available energy is a key factor to optimize the management strategies of the proposed hybrid power plant, allowing to obtain environmental and economic benefits.
1159(2009); http://dx.doi.org/10.1063/1.3223929View Description Hide Description
Several classes of mobile robotic systems are discussed that are based on certain non‐conventional principles of motion and can move along different surfaces and inside various media. Namely, we consider wall‐climbing robots equipped with pneumatic grippers and able to move along vertical walls; snake‐like multilink mechanisms with actuators installed at their joints; and vibro‐robots moving in resistive media and containing movable masses. Kinematics and dynamics of these types of robots are discussed. Optimal geometrical and mechanical parameters as well as optimal periodic motions of robots are determined that correspond to the maximal average speed of locomotion. Results of experiments with prototypes of robots as well as results of computer simulation are presented. The locomotion principles analyzed are applicable to robots that can move in a complicated and hazardous environment, along different surfaces, and inside tubes.
1159(2009); http://dx.doi.org/10.1063/1.3223941View Description Hide Description
This keynote speech discusses mutual intersection of evolutionary techniques and deterministic chaos. Three possible application of evolutinary computation on deterministic chaos are discussed here. The first one discuss chaos synthesis by means of evolutinary computation and the second one chaos control of simple chaotic system. The last, third, part discus use of evolutionary computation on spatiotemporal chaos control.
1159(2009); http://dx.doi.org/10.1063/1.3223951View Description Hide Description
Matrix converters offer certain advantages over conventional AC‐DC‐AC conversion such as elimination of reactive elements, inherent bi‐directional power flow capability, increased reliability and compactness. This paper explores the reactive and harmonic compensation capability of a matrix converter. Space vector modulation technique has been used for controlling the matrix converter. All the details of this work are presented.
1159(2009); http://dx.doi.org/10.1063/1.3223953View Description Hide Description
Load frequency control in power systems introduces as one of the most important items in order to supply reliable electric power with good quality.
The goals of the Load Frequency Control (LFC) are to maintain zero steady state errors in a two area interconnected power system. To achieve this goal a fast controller with having no steady‐state error will be necessary to be included in power systems. In this paper a new genetic algorithm based method is presented to obtain optimal gains of this controller included in two‐area interconnected power system.
Simulation results in comparison with correspondence methods confirm the efficiency of proposed method through fast‐damping steady‐state deviations in power and frequency with presence of step load disturbance.
1159(2009); http://dx.doi.org/10.1063/1.3223954View Description Hide Description
Load forecasting is a crucial aspect of electric power system planning and operation. This paper presents a heuristic approach for optimal parameter estimation of long term load forecast models. The problem is viewed as an optimization one in which the goal is to minimize the total estimation error by properly adjusting the model coefficients. A particle swarm optimization algorithm is developed to minimize the error associated with the estimated model parameters. Real data of Egyptian network is used to perform this study. Results are reported and compared to those obtained using the well known least error squares estimation technique. Comparison results are in favor of the proposed approach which signifies its potential as a promising estimation tool.
1159(2009); http://dx.doi.org/10.1063/1.3223955View Description Hide Description
In recent years, induction generators used in wind farms have found a great importance. Self exciting induction generators main problem is its requirement to a reactive power in order to generate output voltage. In order to provide the mentioned reactive power, using fixed capacitors connected to generator terminals is one of the usual methods. Using variable and switchable capacitor banks is one of the methods to generate reactive power for induction generators and to keep voltage stability since induction generators requirement to reactive power varies by load changes and wind speed. In this paper transient condition accrue by capacitor banks switching in wind farm are simulated by MATLAB and methods are suggested to optimize mentioned conditions.
1159(2009); http://dx.doi.org/10.1063/1.3223956View Description Hide Description
The design principles of the hybrid‐field generator are based on those of a salient pole synchronous machine. The design attempts to combine the characteristics of a permanent magnet generator with the versatility of a wound rotor machine. This concept permits the flux in the air‐gap, produced by the permanent magnets, to be controlled by varying the field coil excitation current. The embedded magnets and field coils are fitted to the salient pole rotor which is the essence of the hybrid‐field generator design. The stator of the synchronous generator has a standard three phase, star connected, distributed winding. Depending on the speed of the machine, the wound rotor field can enable the generator to operate in the boost, permanent magnet (normal) or buck mode, thereby permitting a constant voltage to be generated within the load and speed range. This does not eliminate the use of power electronics but would tend to reduce the rating of the control circuitry and thus reduce the cost as well as the losses. The primary purpose was to optimise or at least substantially improve the magnetic circuit performance in terms of an increase in the output power per unit volume of magnetic material and to investigate whether constant voltages of 24 V, 54 V, 82 V, and 178 V (ac) could be maintained over an extended operational speed range of the prototype. This was attempted through the innovative design of the magnetic circuit and materials, the shape and size of the magnets and pole ends, within the limitations of the existing machine dimensions. The general purpose is therefore to broaden the available knowledge base relevant to the hybrid‐field generator concept for off‐grid applications.
A NEW ONLINE DISTRIBUTED PROCESS FAULT DETECTION AND ISOLATION APPROACH USING POTENTIAL CLUSTERING TECHNIQUE1159(2009); http://dx.doi.org/10.1063/1.3223957View Description Hide Description
Most of process fault monitoring systems suffer from offline computations and confronting with novel faults that limit their applicabilities. This paper presents a new online fault detection and isolation (FDI) algorithm based on distributed online clustering approach. In the proposed approach, clustering algorithm is used for online detection of a new trend of time series data which indicates faulty condition. On the other hand, distributed technique is used to decompose the overall monitoring task into a series of local monitoring sub‐tasks so as to locally track and capture the process faults. This algorithm not only solves the problem of online FDI, but also can handle novel faults. The diagnostic performances of the proposed FDI approach is evaluated on the Tennessee Eastman process plant as a large‐scale benchmark problem.
1159(2009); http://dx.doi.org/10.1063/1.3223958View Description Hide Description
This study investigates a new approach for computational pipeline monitoring. Flow rate, pressure and temperature of the pipe at both ends are measured. Time domain features are extracted from windowed signals. They form separable patterns in the feature space for the normal and leak conditions. Fuzzy classifier is trained with data from a medium leak in the middle of the multiphase pipe. The trained classifier is used to detect leaks with different positions and sizes. Also the ability of the classifier to distinguish operational changes from leakages is evaluated. Results of fuzzy classifier are compared with a neural network classifier and a linear classifier. Results show that this approach obtains good results for pipeline leak detection.
1159(2009); http://dx.doi.org/10.1063/1.3223959View Description Hide Description
With the realization of power quality issues, the use of passive harmonic filters is increasing in all process industries day by day. Therefore it is necessary to find a balance between the commercial aspects and benefits of using harmonic filters. This paper is an effort to highlight the indigenous development of a passive third harmonic filter using a commercial product of ABB Pvt. Ltd. as a model by using reverse engineering technique.
SIMULATION OF SERIES ACTIVE AND PASSIVE POWER FILTER COMBINATION SYSTEM TO MITIGATE CURRENT SOURCE HARMONICS1159(2009); http://dx.doi.org/10.1063/1.3223960View Description Hide Description
This paper discusses a combination three phase system of series active power filter and passive power filter used to mitigate current source harmonics produced by a three phase diode rectifier with capacitive loads. A control method based on synchronous reference frame (SRF) is implemented to compensate for the current harmonics. Computer simulation and modelling of the combined filter system is carried out using Matlab/Simulink Power System Blockset (PSB) software. The single tuned passive power filters suppress 5th and 7th order current harmonics, while the series active power filter acts as a harmonic isolator between the source and load. Hence, the proposed system performs very well in mitigating source current harmonics to the level that comply the harmonic standard such as IEEE 519‐1992.
1159(2009); http://dx.doi.org/10.1063/1.3223961View Description Hide Description
We describe simple implementations of homotopy (also called continuation) algorithm for determining the proper resistor to dissipate energy at a specified rate of an electric circuit. Homotopy algorithm can be considered as a developing of the classical methods in numerical computing such as Newton‐Raphson and fixed point methods. In homoptopy methods, an embedding parameter is used to control the convergence. The method purposed in this work utilizes a special homotopy called Newton homotopy. Numerical example solved in MATLAB is given to show the effectiveness of the purposed method.
1159(2009); http://dx.doi.org/10.1063/1.3223962View Description Hide Description
By operating PV systems near the maximum power point (MPP), the output efficiency of PV panels can be increased. Traditionally, the k‐means algorithm is one of the most popular methods to classify the input patterns of the radial basis function network (RBFN). Although the KMA has an ability to cluster the training patterns rapidly, it usually converges to a local minimum and can be oversensitive to randomly initial partitions. To solve these significant problems, a hybrid skill called Genetic k‐Means Algorithm is proposed to improve the effectiveness of maximum power point track. By precisely clustering of the training patterns, the objective to accurately and rapidly approximate the MPP of PV system can be achieved with the least squares criterion in RBF network.
1159(2009); http://dx.doi.org/10.1063/1.3223912View Description Hide Description
The paper reports used the fuzzy rule Suram for control system of a wood drying chamber with solar as source of energy. Rule suram based of fuzzy logic with variables of weather is temperature ambient and conditions of air is humidity ambient, it implemented for wood drying process. The membership function of variable of state represented in error value and change error with typical of triangle and trapezium map. Result of Analysis to reach 8 fuzzy rule to control the output system can be constructed in a number of way of weather and conditions of air. It used to minimum of the consumption of electric energy by heater. The rule suram used to stability and equilibrium of schedule of drying in chamber by control of temperature and humidity. The result of implemented of fuzzy rule suram with the modification of membership function in range [0.5, 1] represented approximate to he conditions riel.
1159(2009); http://dx.doi.org/10.1063/1.3223913View Description Hide Description
This paper presents a fuel‐cell distributed energy resource with integrated energy storage. A compatible power electronic interface to couple the fuel‐cell with the grid and/or a local load is introduced. Details of the energy storage module, the power electronic interface and the corresponding controls are described. A control strategy for the power electronic interface is developed to manage the flow of power between the fuel‐cell, the energy storage and the grid. A dynamic model for the fuel‐cell distributed resource is developed and is used for the systematic design of the distributed resource control system. Performance of the fuel‐cell distributed energy resource is evaluated based on digital time‐domain simulations in the (Electromagnetic Transient Program) EMTP‐RV software environment. Effectiveness of the energy storage module, the compatible interface and the corresponding controls in enhancing the fuel‐cell distributed resource performance is verified. The results demonstrate the developed power electronic interface and control strategy provide the fuel‐cell with the load‐following capability, the plug‐and‐play feature and high qualities of voltage and power that are required for the microgrid application.
1159(2009); http://dx.doi.org/10.1063/1.3223914View Description Hide Description
In this paper, the time for energy relaxation for Little‐Hopfield neural network using the new activation rule is shown to be better than the relaxation time using Hebbian learning. However, this should be so given the characteristics of the activation function and show through computer simulations that this is indeed so. In this paper, it has been proven that the new learning rule has a higher capacity than Hebb rule by computer simulations.
1159(2009); http://dx.doi.org/10.1063/1.3223916View Description Hide Description
This study presents an analysis of the energy consumption patterns in 10 Arab countries: Saudi Arabia, Kuwait, United Arab Emirates (UAE), Syria, Lebanon, Jordan, Egypt, Libya, Tunisia, and Algeria. Commonalities and variations between these countries are discussed and explained through key economic and energy indicators, and the relationship between the overall final energy consumption per capita and the GDP per capita is examined. The distribution of the final energy consumption across different sectors is also analysed, and the patterns of consumption in the industrial, transportation, and residential sectors are discussed with focus on the types of energy consumed, and the main drivers of this consumption. The findings and the conclusions of this study are believed to be beneficial to the national energy policy planners in identifying possible strengths, weaknesses, and areas of emphasis and improvement in their strategic energy plans.