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Journal ArticleDOI

Design and implementation of a linear quadratic regulator controlled active power conditioner for effective source utilisation and voltage regulation in low-power wind energy conversion systems

TL;DR: In this article, a three-phase modular boost converter supplied from a permanent magnet synchronous generator (PMSG) and controlled using a linear quadratic regulator (LQR) is proposed for battery charging applications.
Abstract: Power electronic converters play a major role in wind energy conversion systems (WECS). A typical variable speed WECS includes wind turbine, permanent magnet synchronous generator (PMSG) and power conditioners. In this study, a three-phase modular boost converter supplied from a PMSG and controlled using a linear quadratic regulator (LQR) is proposed for battery charging applications. Each phase of PMSG is connected to a single phase diode rectifier and a DC–DC boost converter. All boost converters have a common output capacitor and load. The proportional–integral-based voltage controller provides voltage regulation on the DC side. A fixed frequency LQR-based current controller applied for the individual phases provides a better three-phase source utilisation. The instantaneous pq theory is adopted for the reference current calculation. Extensive simulation studies based on the models developed using MATLAB/SIMULINK reveal that the proposed system performs satisfactorily for step variations in wind speed and load. The performance of the low power prototype developed and controlled using a dSPACE 1104 digital signal processor shows good output voltage regulation and better source utilisation for wide variations in load.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors present a comprehensive review of high-power dc-dc converters for high-voltage direct current (HVDC) transmission systems, with emphasis on the most promising topologies from established and emerging DC-DC converters.
Abstract: This study presents a comprehensive review of high-power dc-dc converters for high-voltage direct current (HVDC) transmission systems, with emphasis on the most promising topologies from established and emerging dc-dc converters. In addition, it highlights the key challenges of dc-dc converter scalability to HVDC applications, and narrows down the desired features for high-voltage dc-dc converters, considering both device and system perspectives. Attributes and limitations of each dc-dc converter considered in this study are explained in detail and supported by time-domain simulations. It is found that the front-to-front quasi-two-level operated modular multilevel converter, transition arm modular converter and controlled transition bridge converter offer the best solutions for high-voltage dc-dc converters that do not compromise galvanic isolation and prevention of dc fault propagation within the dc network. Apart from dc fault response, the MMC dc auto transformer and the transformerless hybrid cascaded two-level converter offer the most efficient solutions for tapping and dc voltage matching of multi-terminal HVDC networks.

152 citations


Cites background from "Design and implementation of a line..."

  • ...Also, the increased dependency of the LCC terminal on the ac network strength has caused significant concerns regarding ac voltage stability of relatively weak ac networks, especially when large power is being exchanged [8, 16-26]....

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Journal ArticleDOI
TL;DR: In this article, a grid connected PMSG-based wind turbine assisted with diode bridge rectifier and boost converter is presented, and the linearized average dynamic model of the combined system comprising PMSG, diode rectifier, and boost converter is presented.

68 citations

Journal ArticleDOI
TL;DR: In this paper, a linear-quadratic regulator (LQR) is proposed for damping of subsynchronous interaction (SSI) in doubly-fed induction generator (DFIG)-based wind farms.
Abstract: This paper presents a linear-quadratic regulator (LQR) for damping of subsynchronous interaction (SSI) in doubly-fed induction generator (DFIG)-based wind farms. The proposed LQR controller employs a full-state observer to estimate all state variables. The output of the LQR is added to control signals of inner current control loops of DFIG converters as supplementary control signals. The supplementary control signals are dynamically limited to avoid saturating the converters and to provide the DFIG with the desired transient response against power system faults. The proposed SSI damping controller is designed for a realistic series compensated wind farm, and its performance is verified using electromagnetic transient (EMT) simulations. The EMT simulations are performed using a detailed DFIG model which includes all nonlinearities and all required transient functions to meet the grid code requirements corresponding to fault-ride-through (FRT). The results show that the proposed SSI controller is able to significantly mitigate the oscillations due to the SSI phenomenon, and to provide excellent transient response against systems faults.

65 citations


Cites methods from "Design and implementation of a line..."

  • ...The linear-quadratic regulator (LQR) method has been widely used in power system control due to its simplicity and robustness [16], [17]....

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Journal ArticleDOI
TL;DR: This paper presents the proposal of using two bio-inspired metaheuristics—genetic algorithms (GAs) and particle swarm optimization (PSO)—to adjust the free coefficients of a Gaussian adaptive proportional–integral–derivative (GAPID) controller.
Abstract: This paper presents the proposal of using two bio-inspired metaheuristics—genetic algorithms (GAs) and particle swarm optimization (PSO)—to adjust the free coefficients of a Gaussian adaptive proportional–integral–derivative (GAPID) controller. When a specific adaptation rule is imposed to a conventional proportional–integral–derivative (PID) controller, either by means of a hyperbolic tangent function or a Gaussian function, the solution is left exposed to the function restrictions/impositions. Finding the correct proportionality between the parameters is an arduous task, which often does not have an algebraic solution. Each Gaussian function of each control action has three parameters, resulting in a total of nine parameters to be defined. This paper proposes making the parameters linked to the linear PID gains, in order to keep the GAPID the same design requirements as for the PID. Then, two metaheuristics (GA and PSO) were employed in order to find the best parameters for the GAPID. A comparison between these two strategies is presented. In this investigation, a well-known plant of a step-down dc–dc converter is used, which represents a typical second-order system, where the absence of significant nonlinearities helps focus the study on the control behavior. Simulation and experimentation were performed, and both have been successful, but PSO stood out due to its simplicity and low-computational effort.

46 citations

Journal ArticleDOI
TL;DR: In this paper, a fuzzy logic controller is proposed to fulfill the objective of maximum power extraction based on a two-mass model to illustrate the effectiveness and robustness against parameter variations of the proposed control design.
Abstract: In this paper, a fuzzy logic controller is proposed to fulfill the objective of maximum power extraction based on a two-mass model. One of the crucial problems is that the effective wind speed cannot be measured directly due to the high disturbance of the wind speed and the high cost of sensors. Three algorithms are used to estimate the effective wind speed by solving power balance equations, and the estimated wind speed is used to determine the optimal speed reference for a generator control system. The control performance of the fuzzy logic controller is verified in the whole system and compared with a conventional PI controller. Simulation results are presented to illustrate the effectiveness and robustness against parameter variations of the proposed control design.

37 citations


Cites background from "Design and implementation of a line..."

  • ...Several model based control approaches have been studied for the wind turbine system, such as linear-quadratic regulator (LQR), pole-placement and PID, which provides convenience to implement such controllers in practical applications [3], [19]....

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References
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Book
31 Jul 1997
TL;DR: Converters in Equilibrium, Steady-State Equivalent Circuit Modeling, Losses, and Efficiency, and Power and Harmonics in Nonsinusoidal Systems.
Abstract: Preface. 1. Introduction. I: Converters in Equilibrium. 2. Principles of Steady State Converter Analysis. 3. Steady-State Equivalent Circuit Modeling, Losses, and Efficiency. 4. Switch Realization. 5. The Discontinuous Conduction Mode. 6. Converter Circuits. II: Converter Dynamics and Control. 7. AC Equivalent Circuit Modeling. 8. Converter Transfer Functions. 9. Controller Design. 10. Input Filter Design. 11. AC and DC Equivalent Circuit Modeling of the Discontinuous Conduction Mode. 12. Current Programmed Control. III: Magnetics. 13. Basic Magnetics Theory. 14. Inductor Design. 15. Transformer Design. IV: Modern Rectifiers and Power System Harmonics. 16. Power and Harmonics in Nonsinusoidal Systems. 17. Line-Commutated Rectifiers. 18. Pulse-Width Modulated Rectifiers. V: Resonant Converters. 19. Resonant Conversion. 20. Soft Switching. Appendices: A. RMS Values of Commonly-Observed Converter Waveforms. B. Simulation of Converters. C. Middlebrook's Extra Element Theorem. D. Magnetics Design Tables. Index.

6,136 citations

Book
01 Jan 2007
TL;DR: The p-q theory in three-phase, four-wire Shunt Active Filters as discussed by the authors has been applied to power flow control in power electronics equipment and has been shown to be useful in many applications.
Abstract: Preface. 1. Introduction. 1.1. Concepts and Evolution of Electric Power Theory. 1.2. Applications of the p-q Theory to Power Electronics Equipment. 1.3. Harmonic Voltages in Power Systems. 1.4. Identified and Unidentified Harmonic-Producing Loads. 1.5. Harmonic Current and Voltage Sources. 1.6. Basic Principles of Harmonic Compensation. 1.7. Basic Principles of Power Flow Control. References. 2. Electric Power Definitions: Background. 2.1. Power Definitions Under Sinusoidal Conditions. 2.2. Voltage and Current Phasors and the Complex Impedance. 2.3. Complex Power and Power Factor. 2.4. Concepts of Power Under Non-Sinusoidal Conditions -Conventional Approaches. 2.5. Electric Power in Three-Phase Systems. 2.6. Summary. References. 3 The Instantaneous Power Theory. 3.1. Basis of the p-q Theory. 3.2. The p-q Theory in Three-Phase, Three-Wire Systems. 3.3. The p-q Theory in Three-Phase, Four-Wire Systems. 3.4. Instantaneous abc Theory. 3.5. Comparisons between the p-q Theory and the abc Theory. 3.6. Summary. References. 4 Shunt Active Filters. 4.1. General Description of Shunt Active Filters. 4.2. Three-Phase, Three-Wire Shunt Active Filters. 4.3. Three-Phase, Four-Wire Shunt Active Filters. 4.4. Shunt Selective Harmonic Compensation. 4.5. Summary. References. 5 Hybrid and Series Active Filters. 5.1. Basic Series Active Filter. 5.2. Combined Series Active Filter and Shunt Passive Filter. 5.3. Series Active Filter Integrated with a Double-Series Diode Rectifier. 5.4. Comparisons Between Hybrid and Pure Active Filters. 5.5. Conclusions. References. 6 Combined Series and Shunt Power Conditioners. 6.1. The Unified Power Flow Controller (UPFC). 6.2. The Unified Power Quality Conditioner (UPQC). 6.3. The Universal Active Power Line Conditioner (UPLC). 6.4. Summary. References. Index.

2,038 citations

Journal ArticleDOI
TL;DR: Experimental results of the proposed MPPT system indicate near-optimal WG output power, increased by 11%-50% compared to a WG directly connected via a rectifier to the battery bank, and better exploitation of the available wind energy is achieved, especially under low wind speeds.
Abstract: A wind-generator (WG) maximum-power-point-tracking (MPPT) system is presented, consisting of a high-efficiency buck-type dc/dc converter and a microcontroller-based control unit running the MPPT function. The advantages of the proposed MPPT method are that no knowledge of the WG optimal power characteristic or measurement of the wind speed is required and the WG operates at a variable speed. Thus, the system features higher reliability, lower complexity and cost, and less mechanical stress of the WG. Experimental results of the proposed system indicate near-optimal WG output power, increased by 11%-50% compared to a WG directly connected via a rectifier to the battery bank. Thus, better exploitation of the available wind energy is achieved, especially under low wind speeds.

907 citations

Journal ArticleDOI
TL;DR: In this paper, power converters are classified into single and multicell topologies, with attention to series connection and parallel connection either electrical or magnetic ones (multiphase/windings machines/transformers).
Abstract: The steady growth of installed wind power together with the upscaling of the single wind turbine power capability has pushed the research and development of power converters toward full-scale power conversion, lowered cost pr kW, increased power density, and also the need for higher reliability. In this paper, power converter technologies are reviewed with focus on existing ones and on those that have potential for higher power but which have not been yet adopted due to the important risk associated with the high-power industry. The power converters are classified into single- and multicell topologies, in the latter case with attention to series connection and parallel connection either electrical or magnetic ones (multiphase/windings machines/transformers). It is concluded that as the power level increases in wind turbines, medium-voltage power converters will be a dominant power converter configuration, but continuously cost and reliability are important issues to be addressed.

797 citations

Journal ArticleDOI
TL;DR: In this paper, a generalized theory of instantaneous reactive power for three-phase power systems is proposed, which is valid for sinusoidal or nonsinusoidal, balanced or unbalanced, three phase power systems with or without zero-sequence currents and/or voltages.
Abstract: A generalized theory of instantaneous reactive power for three-phase power systems is proposed in this paper. This theory gives a generalized definition of instantaneous reactive power, which is valid for sinusoidal or nonsinusoidal, balanced or unbalanced, three-phase power systems with or without zero-sequence currents and/or voltages. The properties and physical meanings of the newly defined instantaneous reactive power are discussed in detail. A three-phase harmonic distorted power system with zero-sequence components is then used as an example to show reactive power measurement and compensation using the proposed theory.

755 citations