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This paper presents the evaluation of a passivity based control (PBC) strategy for doubly-fed induction generators having wind turbines as prime movers and operating connected to a power network. The evaluation is intended to demonstrate that a PBC strategy initially designed to control generation at unity power factor can control power exchange at a fixed active power delivery to the grid with different...
In order to most effectively utilize the wind energy and improve the efficiency of wind generation system, an optimum control strategy of doubly-fed induction generators (DFIG) was proposed, which made the system operation for both the maximum wind enemy captured below the rated wind speed. Based on the wind turbine characteristics and basic electromagnetic relationship of DFIG the mathematical models...
This paper presents expected efficiency studies on two possible grid connected small wind turbine systems. One of the systems is based on Permanent Magnet Generator (PMG) and the other system is based on Wound Rotor Induction Generator (WRIG). Experimental test benches for both systems are implemented using Wind Turbine Emulator (WTE) and Maximum Power Point Tracking (MPPT) control strategy. The procedure...
In this paper, the problem of tracking control for variable speed wind induction generator (IG) energy conversion system (WECS) is investigated using nonlinear predictive control. A rotor speed predictive control algorithm has been designed to control the angular speed of the machine in order to allow the WECS operate with maximum power extraction. The generator torque is estimated and injected into...
Current grid codes require the fault ride-through capability of modern wind turbines. During grid faults the reactive current control of the wind turbines should be used to support the grid voltage. With modern protection devices the fault durations are normally in a range of some hundred milliseconds or less. However this time window may be decisive for the stability of the conventional generators...
Notwithstanding the positive environmental impact, the increasing penetration of Distributed Generation (DG) units connected to the distribution network raises new topics concerning the expected response of these during outages. Grid disturbances especially at the transmission level can cause the unwanted disconnection of large amounts of DG, leading to undesired power imbalances causing line overloadings...
This paper deals with a voltage and frequency controller (VFC) of a stand-alone wind energy conversion system using an isolated asynchronous generator (IAG) feeding three-phase four-wire loads. The reference generator currents are estimated using the power balance theory to control the voltage and frequency of IAG system. Two-leg reduced switch integrated voltage source converter (VSC) with a battery...
Wind energy is the fastest growing source of renewable energy in the power industry and it will continue to grow worldwide as many countries are developing plans for its future development. For power system operators, this increasing contribution of wind energy to the grid poses new challenges that need to be addressed in order to ensure the reliability and security of the electric power grid. One...
The active power produced by wind generators is subject to fluctuations due to the stochastic nature of wind. Depending upon the size of the wind farm and the network to which it is connected, active power variations may result in frequency deviations. This can trigger frequency protection devices and lead to undesirable unit trippings. This paper proposes the addition of a small supercapacitor at...
The control algorithms proposed in the literature so far for the Double Output Induction Machine Based Variable Speed Constant Frequency (VSCF) stand alone generators suffer from the disadvantage of loss of `field orientation' during sudden load disturbance at the machine terminal. As a result, undesirable transients are observed in the load voltage during such transients. This paper presents a new...
Wind generation is evolving from single wind turbines to wind power plants with an installed capacity of tens of megawatts. Therefore, wind turbines are also coupled to the transmission grid instead of the distribution grid. Problems arise during grid faults as the behaviour of wind turbines equipped with doubly-fed induction generators differs fundamentally from traditional synchronous generators...
This paper describes the use of generic wind turbine models to study the comparative inertial response of wind turbine technologies, that is, their response to a frequency event on the grid such as loss of generation. The dynamic models are manufacturer-independent and portable to any dynamic modeling software. Four dominant types of wind turbine technology are modeled; the basic fixed-speed model...
This paper deals with a decoupled electronic load controller (DELC) for an isolated asynchronous generator (IAG), used in constant power pico hydro power generation for feeding three-phase four-wire loads. The proposed DELC is used to control the voltage and frequency in the decoupled manner. The proposed decoupled electronic load controller is combination of a voltage regulator (VR) for regulating...
This paper proposes a new vector-based hysteresis current regulator (VBHCR) in the rotor-side converter of DFIG to enhance the control performance under unbalanced supply voltage condition. The “Γ-form” is used for the equivalent circuit of the machine to reduce the modeling complexity. This is followed by presenting the principle and practical implementation of the proposed VBHCR in the DFIG application...
This paper presents a flicker mitigation scheme for the doubly-fed induction generator (DFIG) during variable wind conditions. The flicker mitigation strategy was developed based on the distribution line X/R ratio and the active power deviation from the average active power during variable wind conditions. Flicker emission was analyzed using a flicker meter based on the IEC standards. Both short-term...
A novel hybrid Remote Area Power Supply (RAPS) system consisting of a Doubly Fed Induction Generator (DFIG) based wind turbine and a battery Energy Storage System (ESS) is investigated in this paper. The proposed RAPS system also consists of a dummy load and its controller. The battery energy storage system is used as a buffer which is connected to the DC link of the DFIG. The dummy load which is...
Doubly-Fed Induction Generators (DFIGs) are commonly utilized in wind farms nowadays due to their advantages as compared with single fed ones. Control complexities and their unique dynamic characteristics may, however, raise different problems during abnormal or faulty operating conditions. Accordingly, the behavior of the associated protective elements at the Point of Common Coupling Point (PCC)...
This paper deals with an integrated voltage and frequency controller (IVFC) for a self excited induction generator (SEIG) in a standalone micro hydro system. The proposed IVFC is used to control the terminal voltage as well as frequency of SEIG system. This IVFC consists of a 3-phase 3-leg current controlled voltage source converter (CC-VSC) and its control scheme is realized using power balance theory...
In this paper, a speed sensorless vector control strategy for a double output induction generator operating in the Variable Speed Constant Frequency (VSCF) mode is presented. A new reactive power based Model Reference Adaptive System (MRAS) is proposed to estimate the slip speed. The proposed controller is capable of speed catching operation. Simulation results are presented to validate the effectiveness...
An efficient discrete-time approach for the computation of the steady-state operating point of a wind park is presented in this paper. The Finite Differences method and a Newton approach are applied to determine the steady-state solution of the wind park. Besides, the incorporation of sparse techniques improves the efficiency of the discrete-time solution in terms of storage and computational effort...
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