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The paper contribute to establish pragmatic methods to obtain modeling, identification and control laws of double stator windings induction generator DSWIG. The DSWIG model is obtained by formally juxtaposing/over lapping two induction machines, mechanically and magnetically identical to the real DSWIG machine, and having as stator winding the DSWIG load winding, one of them, and the second one having,...
The article is focused on specific issues arising for a photovoltaic panel (PV). In this case, the short circuit current is measured to determine the value of prescribed current corresponding to maximum power point. The results obtained by imposing a load resistance with this method are energy maximum possible, thus justifying the usefulness of this process very simple and inexpensive applied in practice.
The present paper presents specific issues that arise in Photovoltaic Energy Conversion Systems, being focused on maximizing the output power. There is proposed a model for Photovoltaic PV panel external characteristics. The coordinates of maximum power point are determined and used for imposing the appropriate load resistance to maximize the provided power. A comparison is made considering the classical...
The paper presents some considerations regarding the problematic of asynchronous generator's (AG) excitation. There are presented some theoretical considerations regarding the efficiency of the capacitive excited asynchronous generator compounding regarding the load voltage variation compensation. There is presented the determination of the compounding condenser's capacity by using the graph-analytical...
This paper presents considerations of using wireless sensor networks for monitoring conditions within wind farms, taking into considerations the specific of such applications. In these scenarios, which are intended to cover a lot of ground or even operate in difficult radio environments with strong attenuation, the simple and direct communication between source and destination is not always possible,...
This paper presents a self-tuning adaptive control structure designed through the minimization of a criteria function. It is described the computation methodology of the control law, being particularized for the case of a dual winding induction generator's excitation control. The parameter's estimator, integrated into the control system, is based on the on-line least mean square error algorithm. In...
The paper presents a study for implementing a brake sequence for a small wind generator for regimes that exceeds the rated values. Considering data from a real wind generator, two scenarios are presented: first, during a strong wind gust both the electrical and the mechanical brakes are coupled and, for the second case, a fault in the permanent magnet synchronous generator (PMSG) is caused. This study...
There were conceived original methods that intend to optimize (maximize) the efficiency of variable speed fixed blade wind generators. These methods are based on mathematical models of fixed blades wind turbines windmills. This is the main reason that an important part of the paper is dedicated to the problematic of mathematical modeling of the wind turbine - focused mainly on the determination from...
The paper presents a control strategy for a wind energy conversion system (WECS) for an optimal extraction of power from the wind. The topology of the system consists of a permanent magnet synchronous generator (PMSG), a diode bridge rectifier, a hybrid dc-dc converter which lowers the dc voltage, a supercapacitor and an inverter. However, the grid side inverter is not subject to this paper research...
This paper presents the implementation of a neural network-based fault detection for wireless sensor networks (WSNs). There are discussed two proposed approaches: both a centralized and respectively distributed fault detection. The methods are validated using a wireless sensor network that takes environmental measurements every 60 seconds. There were considered various fault scenarios that were detected...
The paper presents some issues regarding an online tuning procedure for a recursive last mean square (RLMS) parameter estimator embedded into an adaptive controller used to control the terminal voltage of a synchronous generator. The analysis is mainly focused on the problematic regarding the reinitialization of the covariance matrix within the RLMS algorithm. A study case for a dynamical model, with...
The paper proposes Markov models for the reliability analysis of the wireless sensor networks with standby backup elements. There are presented the theoretical aspects and some of the variables that are used in the domain of fault tolerant systems. There has been conducted a study regarding the reliability of system versus cost price, considering different number of hot redundant spare parts. Reliability...
The paper proposes Markov models for the reliability analysis of the wireless sensor networks. There are presented the theoretical aspects and some of the variables that are used in the domain of fault tolerant systems. There is also presented a comparison between systems using dedicated replacements and universal replacements for defective nodes. There has been conducted a study regarding the reliability...
The paper presents issues on a software platform implemented by the authors, for the on-line evaluation of the study disciplines and of the involved academic staff, made by the students. There are presented the main features of the elaborated software product, the architecture and issues regarding the graphical user interface. Also, there are presented conclusions regarding the advantages of the usage...
The present paper presents considerations on using a low power routing solution for prolonging the battery life for motes within a wireless sensor network (WSN) without affecting the network connectivity. The solution applies for the cases when, the distances between motes and base stations are over the mote's communication range, and motes located between sinks and base station are commonly used...
In some cases of software-distributed applications, a large data amount must be accessed by a large number of users (dispersed geographically). In these cases, the database replication process provides an efficient solution to increase the application performances. This paper presents two methods to implement a multi-master database replication process. A replication example between two Oracle databases...
The present paper presents a solution for prolonging the battery life for motes within a wide-area wireless sensor network (WSN). In this particulars networks, the distances between motes and base stations are over the motepsilas communication range, and motes located between sinks and base station are commonly used both as regular motes and repeaters. This diminishes their energetic autonomy and...
The wind energy conversion systempsilas (WECS) analysis requires the priory knowledgepsilas regarding the mathematical models for all component subsystems. The paper highlights some contributions to the preset values establishing strategies and models of certain components: rotation speed and voltage preset values establishing strategies, a simplified wind turbine model (fixed blade turbine), the...
In this paper a study on the convergence properties of various parameter-estimation methods (both open and closed loop evolution) integrated in a control structure elaborated for the considered process is presented. Furthermore, stability analysis of several self-tuning control systems is provided on the basis of which conclusions are drawn regarding the design of self-tuning controllers.
The paper focuses on experimental investigation for stator faults detection and fault detection methods of electrical drive systems using voltage source inverter (VSI) fed cage rotor induction machines (CRIM). Two experimental investigations (one stator phase unbalance and one stator phase open) have been performed to study the behaviour of the electrical machine. A description of the measurement...
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