Improvement in Power Quality of Matrix Converter Interfaced Wind Turbine Emulator

We have seen that the nominal power of single Wind Energy Converter Systems has been steadily growing up and reaching power ratings close to 10 MW. In the power conversion stage, we found that the medium-voltage power converters are replacing the conventional low-voltage back-to-back topology. Due to this reason the Matrix Converters interfaced have appeared as a promising solution for Multi-MW WECSs due to their characteristics such as modularity, reliability and the capability to reach high nominal voltages. In 2009-10, the country imported 159.26 million tons of crude oil which amounts to 80% of its domestic crude oil consumption and 31% of the country\u27s total imports are oil imports. The growth of electricity generation in India has been hindered by domestic coal shortages and as a consequence, India\u27s coal imports for electricity generation increased by 18% in 2010. So in this paper I try to develop fuzzy-logic based control strategy to capture maximum wind energy and reduce harmonics for proposed wind generation system and then develops fuzzy control for indirect matrix converter under steady-state and dynamic conditions. With these assumptions finally try to validate the proposed wind generation system in simulation environment to validate the developed control algorithms under various balanced /unbalanced conditions. Finally evaluate the performance of the developed wind generation system and its controls under various balanced/unbalanced wind conditions. During investigating details the robustness of the steady-state and dynamic performance of the developed system under various balanced/unbalanced conditions using simulation software I presents the experimental performance evaluation of the developed matrix converter prototype with wind emulator. Keywords: Wind energy conversion system (WECS), Matrix converter, Wind emulator, space vector pulse width modulation (SVPWM), permanent magnet synchronous generators (PMSGs), wind farms (WFs)

Improvement in Power Quality of Matrix Converter Interfaced Wind Turbine Emulator

We have seen that the nominal power of single Wind Energy Converter Systems has been steadily growing up and reaching power ratings close to 10 MW. In the power conversion stage, we found that the medium-voltage power converters are replacing the conventional low-voltage back-to-back topology. Due to this reason the Matrix Converters interfaced have appeared as a promising solution for Multi-MW WECSs due to their characteristics such as modularity, reliability and the capability to reach high nominal voltages. In 2009-10, the country imported 159.26 million tons of crude oil which amounts to 80% of its domestic crude oil consumption and 31% of the country\u27s total imports are oil imports. The growth of electricity generation in India has been hindered by domestic coal shortages and as a consequence, India\u27s coal imports for electricity generation increased by 18% in 2010. So in this paper I try to develop fuzzy-logic based control strategy to capture maximum wind energy and reduce harmonics for proposed wind generation system and then develops fuzzy control for indirect matrix converter under steady-state and dynamic conditions. With these assumptions finally try to validate the proposed wind generation system in simulation environment to validate the developed control algorithms under various balanced /unbalanced conditions. Finally evaluate the performance of the developed wind generation system and its controls under various balanced/unbalanced wind conditions. During investigating details the robustness of the steady-state and dynamic performance of the developed system under various balanced/unbalanced conditions using simulation software I presents the experimental performance evaluation of the developed matrix converter prototype with wind emulator

Design and implementation of variable speed wind energy induction generator systems for fault studies

Includes bibliographical references (leaves [136]-139).Due to the economical and environmental benefits, Wind Energy Conversion Systems (WECS) have received tremendous growth in the past decade. The increased interest in wind energy has made it necessary to model and experimentally evaluate entire WECS, so as to attain a better understanding and to assess the performance of various systems. As a direct consequence of the increase in wind generation systems, comes the need for the reduction of operational and maintenance costs of these wind generators. The most efficient way of reducing these costs is by the early detection of the degeneration of these generators health, thus facilitating a proactive response, minimizing downtime, and maximizing productivity. The more common induction machine failures are caused by the deterioration of the stator insulation and by the breaking of rotor bars. The thesis describes the design, modeling and implementation of two different variable speed induction generator systems for studying faults in wind energy applications. This project served as a platform for further research into the development and evaluation of a non-stationary fault detection technique suitable for wind energy induction generator purposes. Some common faults are implemented on the wind generators in an attempt to identify them from measurements and by using a steady state fault analysis technique (Motor Current Signature Analysis). For variable speed wind generation, there are two systems using induction generators. The first consist of a squirrel cage induction generator, which uses back-to-back converters in the stator circuit, as shown in Fig. 0.1. The second consists of a wound rotor induction generator, whereby the stator is directly connected to the grid and the rotor circuit consists of back-to-back converters, as shown in Fig. 0.2. When both the rotor and stator are capable of delivering power as with the wound rotor induction generator, they are known as doubly-fed induction generators (DFIG)

Source Grid Interface of Wind Energy Systems

Wind power is one of the most developed and rapidly growing renewable energy sources. Through extensive literature review this thesis synthesizes the existing knowledge of wind energy systems to offer useful information to developers of such systems. Any prototyping should be preceded by theoretical analysis and computer simulations, foundations for which are provided here. The thesis is devoted to an in-depth analysis of wind energy generators, system configurations, power converters, control schemes and dynamic and steady state performance of practical wind energy conversion systems (WECS). Attention is mainly focused on interfacing squirrel cage Induction generators (SCIG) and doubly-fed induction generators (DFIG) with the power network to capture optimal power, provide controllable active and reactive power and minimize network harmonics using the two-level converter, as a power electronic converter. Control of active and reactive power, frequency and voltage are indispensable for stability of the grid. This thesis focuses on two main control techniques, field oriented control (FOC) and direct torque control (DTC) for the SCIG. The dynamic model of induction generator is non-linear and hence for all types of control, the flux and the torque have to be decoupled for maintaining linearity between input and output for achieving high dynamic performance. FOC is used for decoupled control for rotor flux and electromagnetic torque . The stator current is decomposed into flux and torque producing components and they both are controlled independently. FOC uses three feedback control loops generate gating signals for the converter. DTC also achieves high dynamic performance by decoupling of rotor flux and electromagnetic torque without the intermediate current loops. DTC asks for the estimation of stator flux and torque and like FOC has 2 branches which have flux and torque comparators. The errors between the set and the estimated value are used to drive the inverters. The two methods are valid for both steady and transient state. Their validity is confirmed by simulating the systems on MATLAB/Simulink platform and comparing them the results obtained by hand calculations. Further DFIG’s are introduced. The dynamic model is developed using the machines equivalent circuit and is expressed in the stationary, rotor and the synchronous reference frames for evaluating the performance of the machine. The stator of the DFIG is directly interfaced to the grid and by controlling the rotor voltage by a two level back-to-back converter the grid synchronization and power control is maintained. The DTC and the direct power control (DPC) methods are used to control the rotor side (RSC) and the grid side converter (GSC). The RSC generates the 3-ph voltages of variable frequency in order to control the generator torque and the reactive power exchanged between the stator and the grid. The GSC exchanges active power with the grid injected by the RSC with a constant frequency. The steady and transient behavior of the machine is investigated through simulations

Multi-phase generators viability for offshore wind farms with HVDC transmission

Política de Open Access indicada en la web del editor. No aparece la revista en Sherpa/RomeoThe interest in offshore wind farms has experienced a significant growth in recent years. Technical knowledge allow the design of wind farms at higher distances, making the high voltage dc (HVDC) transmission a real alternative to current high voltage ac (HVAC) transmission. When the network is decoupled from the wind farm by a dc link, there is no need for a mandatory use of three-phase generator. To the contrary, multi-phase generators can be used and the wind farm can benefit from inherent advantages and recent developments of multi-phase drives. This preliminary study shows some of the potential advantages of the dual three-phase generators in wind energy conversion systems (WECS)

Robust nonlinear control of wind turbine driven doubly fed induction generators

This paper presents the active and reactive powers control of a doubly fed induction generator (DFIG) connected to the grid utility and driven by a wind turbine, this machine allowing a large speed variation and so a large range of wind is achieved. Traditionally vector control is introduced to the DFIG control strategies, which decouples DFIG active and reactive powers, and reaches good performances in the wind energy conversion systems (WECS). However, this decoupling is lost if the parameters of the DFIG change. In this direction, a robust control scheme based on the nonlinear input-output linearizing and decoupling control strategy for the rotor side converter (RSC) of the WECS is presented. Simulation results show that the proposed control strategy provides a robust decoupled control and perfect tracking of the generated active and reactive powers of the wind turbine driven DFIG with a low THD rate of the generated currents

Multivariable control of a grid-connected wind energy conversion system with power quality enhancement

This document is the Accepted Manuscript version of the following article: Kaddour Fouad, Houari Merabet Boulouiha, Ahmed Allali, Ali Taibi, and Mouloud Denai, ‘Multivariable control of a grid-connected wind energy conversion system with power quality enhancement’, Energy Systems, Vol. 9 (1): 25-57, February 2018. The final publication is available at Springer via: https://doi.org/10.1007/s12667-016-0223-7This paper proposes the design of a multivariable robust control strategy for a variable-speed WECS based on a SCIG. Optimal speed control of the SCIG is achieved by a conventional PI controller combined with a MPPT strategy. DTC-SVM technique based on a simple Clarke transformation is used to control the generator-side three-level converter in the variable speed WECS. The flow of real and reactive power between the inverter and the grid is controlled via the grid real and reactive currents and the DC link voltage using multivariable H∞ control. The overall WECS and control scheme are developed in Matlab/Simulink and the performance of the proposed control strategy is evaluated via a set of simulation scenarios replicating various operating conditions of the WECS such as variable wind speed and asymmetric single grid faults. The power quality of the WECS system under H∞ control control approach is assessed and the results show a significant improvement in the total harmonic distorsion as compared to that achieved with a classical PI control.Peer reviewedFinal Accepted Versio