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Shaft generator (SG) systems have been exploited for long due to several appealing advantages they present. This type of generators is installed at the shaft of the main propulsion diesel engine while they are capable of operating as propulsion engine boosting devices if suitable power electronics are used. In this paper an effort is made to provide a comprehensive analysis of shaft generator role...
The project is based on the design of an electric network embedded in a helicopter. The electric network supplies the aircraft auxiliaries. It is powered by a turbo alternator and hybridized with other electric sources in order to fulfil the demand of the auxiliaries and to limit the consumption on the main source. In this paper, the studied hybrid system is composed of the main source (the turbine...
In the past few years, quite a few cases have arisen where shorted turns were detected or suspected on a pole of a hydrogenerator. In many instances, the shorted turns are suspected because of sudden excessive vibrations near the rotor, which are observed when the magnetic field suddenly appears in the air gap. In other instances, scheduled tests during outages, such as voltage drop tests, are performed...
This paper introduces a novel DSP-based emulator that employs a 3-phase current controlled inverter to reproduce the dynamic behavior of marine current turbines. The proposed marine current emulator provides a flexible platform to modify the resource conditions, test different combinations of the turbine's parameters, and supervise the system variables in real time. These characteristics allow the...
Wind is uncontrolled and non-deterministic and causes unexpected variations in wind power and power generation in wind energy conversion systems. The drive train subjected to a varying wind power develops transients at various levels owing to interaction among the mechanical and electrical variables with non-linear characteristics. A transient performance analysis has been carried out showing the...
An analysis and modeling approach of an electromechanical harvesting system based on a brushless generator (BLG) is presented and evaluated. The approach is based on an electrical analog of the mechanical components and was verified by modeling a knee joint harvesting system. Good agreement was found between the model predictions and the experimental results. New harvesting strategies based on energy...
Gearbox faults constitute a significant portion of all faults and downtime in wind turbines (WTs). Current-based gearbox fault diagnosis has significant advantages over traditional vibration-based techniques in terms of cost, implementation, and reliability. This paper derives a mathematical model for a WT drive train consisting of a two-stage gearbox and a permanent magnet (PM) generator, from which...
Anelectromagnetic energy harvester is designed to harness the vibrational power from railroad track deflections due to passing trains. Whereas typical existing vibration energy harvester technologies are built for low power applications of milliwatts range, the proposed harvester will be designed for higher power applications for major track-side equipment such as warning signals, switches, and health...
Made use of the vibration signals of main shaft which were measured from a normal direct-driven wind turbine and a fault one, the vibration characteristics of main shaft bearing were analyzed and studied. From time domain, frequency domain and cepstrum domain, analyzed and compared the vibration signal characteristics between normal and fault units, then narrowband envelope analysis had been made...
In this paper, a control method for a Wind Energy Conversion System (WECS) utilizing a Squirrel Cage Induction Generator (SCIG) is presented. Aims of the control are both maximum wind power harvesting and minimization of the SCIG power loss, thus achieving maximum power production on any wind speed. The SCIG is connected to the utility grid through two back-to-back converters. The first converter...
This paper deals with the control of small-power wind turbine using fixed-pitch blades. A three-phase permanent magnet (PM) brushless generator is connected to the grid through a double stage converter: active rectifier (VSR) + d.c.-link + inverter (VSI). A very simple and effective control strategy of the generation set (PM generator +VSR) is presented; it is mainly aimed to extend the wind-turbines...
Wind turbines represent elastically coupled multi-mass systems. Dynamic load changes caused by a gust of wind lead to peaks in the shaft torsion torque and result into high stress for the system. This paper presents an opportunity to integrate a stress minimizing control strategy, which was presented in [7], on wind turbines with doubly fed induction generator (DFIG). To avoid extensive measurements...
This paper focuses on the changing requirements for small power units connected to the grid and the task of stability studies to ensure the adherence of this requirements. Belong the coupled simulation of grid faults to determine the critical fault clearing time of a machine the main influences on the ability of a machine on keeping connected to the grid during a fault with deep voltage transients...
Direct drive (DD) wind turbine has lots of benefits, such as low noise, small size and high efficiency in low wind speed, etc. therefore it will be the main model in future wind power market. This paper presents different structures of DD wind turbines from major wind power manufacturers and compares several main drive train structures. Result of this research can provide relevant reference for manufacturers...
The paper presents analysis of the torsional torques of a turbine generator rotor system in a meshed AC network with monopolar HVDC link following symmetrical and asymmetrical faults. The emphasis of the work is on establishing the influence of uncertainties in the mechanical parameters of turbine-generator shaft system on maximum torsional torques. Three loading conditions of turbine generator are...
This paper provides an overview of subsynchronous resonance, subsynchronous torsional interaction, and related phenomena. Beginning with the first, and only, case of shaft damage due to subsynchronous resonance, this paper also describes other types of potential torsional interaction as well as various methods of mitigation and protection. It ends with a description of the most recent concerns about...
In this paper, we will study the influence of the blades and shaft's rigidity on the stability of wind generator when a voltage dip appears. First, we present the model of the wind turbine, taking into consideration all damping coefficients. In this case the turbine will be represented by a three masses model. Then, neglecting the turbine blades' damping model becomes two masses. Finally, considering...
A solar concentrator/gas turbine is described in which solar radiation is directed by mirrors, etc, through windows in the turbine casing. This radiation is used to heat absorbing surfaces inside the turbine, thus heating the circulating gas. This hot gas then produces a thermodynamic (Brayton) cycle, which is used to drive a generator. The optical properties of solar selective surfaces for the windows...
Wind energy is one of the most popular and economic renewable energy generations. According to the statistics, there is about 3GW wind energy power potentially in Taiwan. If the grid-connected wind turbine generator is subjected to the network faults, the induced electromagnetic torque (E/M torque) leads to torsional torque stresses on turbine mechanism, namely high/low speed shafts and blades. This...
This paper studied the generation states and the control rules of the wind turbine. Taking into account some analysis methods of the stability and the mechanical level of the whole wind turbine system with the quadratic generator torque controller, the wind turbine model was presented and the control rule was designed. After that, this paper showed that the turbine system was integral input-to-state...
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