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Induction Generator (induction + generator)
Selected AbstractsTransient stability simulation of wind generator expressed by two-mass modelELECTRICAL ENGINEERING IN JAPAN, Issue 3 2008Yoshikazu Shima Abstract Recently, wind power generation is increasing worldwide. In wind power stations, induction machines are mostly used as generators. Since induction generators have a stability problem similar to the transient stability of synchronous machines, it is important to analyze the transient stability of power systems including wind generators. Although there have been some reports analyzing the transient stability problem, wind turbine and wind generator are, in most cases, modeled as a one-mass shaft system having total inertia constant. This paper presents simulation analyses of transient stability of power system including induction generator which is expressed by a two-mass shaft model and analyzes an effect of shaft system modeling on the transient stability characteristics. Simulations are performed by PSCAD/EMTDC in this study. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(3): 27,37, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20394 [source] State criterion of wind turbine generator operation using tower shadow effect (Part 2)ELECTRICAL ENGINEERING IN JAPAN, Issue 1 2008Tadashi Naitoh Abstract In order to obtain wind energy effectively, the pole-change-type induction generators are used as the wind turbine generators. Otherwise, the pole-change-type induction generator causes the voltage dips at pole changing time. To maintain the power quality, it is important to know the state change of the generator operation. Therefore, the authors have studied a state criterion of generator using the tower shadow effect, which is the active power oscillation caused by a rotation torque drop when the tower and the turbine blade overlap each other. In this paper, an improved identification method of oscillation frequency, which is the criterion of wind turbine generator operation, is proposed. The proposed method is applied to measured data and good results are obtained. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(1): 25,31, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20395 [source] Autonomous power system for island or grid-connected wind turbines in distributed generationEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 7 2008Grzegorz Iwanski Abstract Modern power generation systems for wind turbines are often based on the rotor fed slip-ring machines. Power electronics converter provides the slip power, and also the reactive power for excitation of the generator during standalone operation. This way the isolated load can be supplied even if the grid has failed. Stator voltage in an autonomous operation is controlled using vectorial phase locked loop (PLL) structure; therefore the information about mechanical speed or angular position of the rotor is eliminated from the control method. The second PLL is also used for synchronization of the generated voltage with the grid voltage. Voltages synchronization is necessary for soft connection and protection of the supplied load from the rapid change of the supply voltage phase. The grid-connected doubly fed induction generator (DFIG) can be useful after grid fault; however, the mains outage detection methods are necessary for fast disconnection after grid failures. Copyright © 2008 John Wiley & Sons, Ltd. [source] Integrating electrical and aerodynamic characteristics for DFIG wind energy extraction and control studyINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2010Shuhui Li Abstract A doubly fed induction generator (DFIG) wind turbine depends on the control of the system at both generator and turbine levels, and the operation of the turbine is affected by the electrical characteristics of the generator and the aerodynamic characteristics of the turbine blades. This paper presents a DFIG energy extraction and control study by combining the two characteristics together in one integrative environment to examine various factors that are critical for an optimal DFIG system design. The generator characteristics are examined for different d-q control conditions, and the extracted power characteristics of the turbine blades versus generator slip are presented. Then, the two characteristics are analyzed in a joint environment. An integrative study is conducted to examine a variety of parametric data simultaneously for DFIG maximum wind power extraction evaluation. A close-loop transient simulation using SimPowerSystem is developed to validate the effectiveness of steady-state results and to further investigate the wind energy extraction and speed control in a feedback control environment. Copyright © 2009 John Wiley & Sons, Ltd. [source] A geometric approach for the design of MIMO sliding controllers.INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2009Application to a wind-driven doubly fed induction generator Abstract This paper presents a systematic methodology to design controllers for a general class of nonlinear MIMO systems affine in the control in the presence of bounded uncertainties and disturbances. The design method is developed using a theoretical framework based on the combination of a geometric approach and sliding mode techniques. The resulting robust control law guarantees finite time convergence, whereas chattering reduction is achieved by utilizing the minimum discontinuous action required to ensure disturbance rejection. The proposed methodology is applied to the control of a grid-connected wind energy generation system based on a doubly fed induction generator. The control objectives considered in this paper are maximization of the wind energy conversion and reactive power regulation to minimize machine losses. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||