The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
George Weiss - One of the best experts on this subject based on the ideXlab platform.
-
linear parameter varying control of a doubly fed induction generator based wind turbine with primary grid frequency support
International Journal of Robust and Nonlinear Control, 2014Co-Authors: Chen Wang, George WeissAbstract:SUMMARY This paper proposes a control method for a doubly fed induction generator (DFIG) driven by a wind turbine, whose rotor is connected to the power grid via two Back-to-Back Pulse-width modulation power converters. First, we design a rotor current controller for this system using the linear matrix inequality based approach to linear parameter varying systems, which takes into account the nonlinear dynamics of the system. We propose a two-loop hierarchical control structure. The inner-loop current controller, which considers the synchronous speed and the generator rotor speed as the components of the parameter vector, achieves tracking of the rotor current reference signals. The outer-loop electrical torque controller aims for wind energy capture maximization and also grid frequency support, and it generates the reference rotor current. We perform a controller reduction for the inner-loop linear parameter varying controller, which is not doable by conventional model-reduction techniques, because the controller is parameter dependent. In simulation, the reduced-order controller has been tested on a nonlinear fourth-order DFIG model with a two-mass model for the drive train. Stability and high performance have been achieved over the entire operating range of the DFIG in the wind turbine. Simulation results have demonstrated the capability of the proposed two-loop control system to implement also grid frequency support. Copyright © 2013 John Wiley & Sons, Ltd.
G K Singh - One of the best experts on this subject based on the ideXlab platform.
-
performance evaluation of multiphase induction generator in stand alone and grid connected wind energy conversion system
Iet Renewable Power Generation, 2018Co-Authors: K A Chinmaya, G K SinghAbstract:This study presents a detailed performance analysis of multi-phase (six-phase) induction generator in conjunction with different types of wind energy conversion systems (WECS). It targets to emphasise the advantages of considering an asymmetrical six-phase induction generator (ASIG) in stand-alone, grid-connected fixed speed and grid-connected variable speed operation. Various aspects such as efficiency, reliability and productivity are considered while performing the analysis. In stand-alone mode, reliability and efficiency of the self-excited ASIG are ascertained by disconnecting one of the two three-phase sets connected to a resistive load. In grid-connected fixed speed mode, two different scenarios are implemented to pursue the applicability of ASIG. In the first scenario, only one three-phase winding set is connected to the grid and another set is connected to a local resistive load. In the second scenario, both three-phase windings are connected to the grid via Y− Δ /Y three-winding transformer. Variable speed operation in grid-connected mode is accomplished by employing Back-to-Back Pulse-width modulation converters between the generator and grid. In this configuration, ASIG is operated with indirect field oriented control to obtain maximum aerodynamic efficiency. Transmission of active and reactive power is monitored with vector-oriented control. Experimental results of considered scenarios are presented to verify the viability of ASIG in various configurations of WECS.
Ruben Pena - One of the best experts on this subject based on the ideXlab platform.
-
Sensorless vector control of induction machines for variable-speed wind energy applications
IEEE Transactions on Energy Conversion, 2004Co-Authors: Roberto Cardenas, Ruben PenaAbstract:A sensorless vector-control strategy for an induction generator in a grid-connected wind energy conversion system is presented. The,sensorless control system is based on a model reference adaptive system (MRAS) observer to estimate the rotational speed. In order to tune the MRAS observer and compensate for the parameter variation and uncertainties, a separate estimation of the speed is obtained from the rotor slot harmonics using an algorithm for spectral analysis. This algorithm can track fast dynamic changes in the rotational speed, with high accuracy. Two Back-to-Back Pulse-width-modulated (PWM) inverters are used to interface the induction generator with the grid. The front-end converter is also vector controlled. The dc link voltage is regulated using a PI fuzzy controller. The proposed sensorless control strategy has been experimentally verified on a 2.5-kW experimental set up with an induction generator driven by a wind turbine emulator. The emulation of the wind turbine is performed using a novel strategy that allows the emulation of high-order wind turbine models, preserving all of the dynamic characteristics. The experimental results show the high level of performance obtained with the proposed sensorless vector-control method.
V. T. Ranganathan - One of the best experts on this subject based on the ideXlab platform.
-
A method of tracking the peak power points for a variable speed wind energy conversion system
IEEE Transactions on Energy Conversion, 2003Co-Authors: Rajib Datta, V. T. RanganathanAbstract:In this paper, a method of tracking the peak power in a wind energy conversion system (WECS) is proposed, which is independent of the turbine parameters and air density. The algorithm searches for the peak power by varying the speed in the desired direction. The generator is operated in the speed control mode with the speed reference being dynamically modified in accordance with the magnitude and direction of change of active power. The peak power points in the P-ω curve correspond to dP/dω=0. This fact is made use of in the optimum point search algorithm. The generator considered is a wound rotor induction machine whose stator is connected directly to the grid and the rotor is fed through Back-to-Back Pulse-width-modulation (PWM) converters. Stator flux-oriented vector control is applied to control the active and reactive current loops independently. The turbine characteristics are generated by a DC motor fed from a commercial DC drive. All of the control loops are executed by a single-chip digital signal processor (DSP) controller TMS320F240. Experimental results show that the performance of the control algorithm compares well with the conventional torque control method.
Chen Wang - One of the best experts on this subject based on the ideXlab platform.
-
linear parameter varying control of a doubly fed induction generator based wind turbine with primary grid frequency support
International Journal of Robust and Nonlinear Control, 2014Co-Authors: Chen Wang, George WeissAbstract:SUMMARY This paper proposes a control method for a doubly fed induction generator (DFIG) driven by a wind turbine, whose rotor is connected to the power grid via two Back-to-Back Pulse-width modulation power converters. First, we design a rotor current controller for this system using the linear matrix inequality based approach to linear parameter varying systems, which takes into account the nonlinear dynamics of the system. We propose a two-loop hierarchical control structure. The inner-loop current controller, which considers the synchronous speed and the generator rotor speed as the components of the parameter vector, achieves tracking of the rotor current reference signals. The outer-loop electrical torque controller aims for wind energy capture maximization and also grid frequency support, and it generates the reference rotor current. We perform a controller reduction for the inner-loop linear parameter varying controller, which is not doable by conventional model-reduction techniques, because the controller is parameter dependent. In simulation, the reduced-order controller has been tested on a nonlinear fourth-order DFIG model with a two-mass model for the drive train. Stability and high performance have been achieved over the entire operating range of the DFIG in the wind turbine. Simulation results have demonstrated the capability of the proposed two-loop control system to implement also grid frequency support. Copyright © 2013 John Wiley & Sons, Ltd.
