The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Adrian V. Timbus - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of current controllers for Distributed Power Generation systems
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    This paper discusses the evaluation of different current controllers employed for grid-connected Distributed Power Generation systems having variable input Power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation is also presented. Since the paper discusses the implementation of these controllers for grid-connected applications, their evaluation is made in three operating conditions. First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input Power variations and grid voltage faults is also examined. Experimental results in each case are presented in order to evaluate the performance of the controllers.

  • flexible active Power control of Distributed Power Generation systems during grid faults
    IEEE Transactions on Industrial Electronics, 2007
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Frede Blaabjerg
    Abstract:

    The increasing penetration of Distributed Power Generation into the Power system leads to a continuous evolution of grid interconnection requirements. In particular, active Power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active Power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.

  • independent pq control for Distributed Power Generation systems under grid faults
    Conference of the Industrial Electronics Society, 2006
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Marco Liserre, R Teodeorescu, Frede Blaabjerg
    Abstract:

    This work aims to present a generalized vector-based formulation for calculating the grid-side current reference of Distributed Power Generation systems in order to independently control active and reactive Power delivered to the grid. Strategies for current reference Generation were implemented on the abc stationary reference frame and their effectiveness was demonstrated experimentally, perhaps validating the theoretical analysis even under grid fault conditions.

  • Control Strategies for Distributed Power Generation Systems Operating on Faulty Grid
    2006 IEEE International Symposium on Industrial Electronics, 2006
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    The Distributed Power Generation based on renewable energy sources such as wind and sun experiences a high penetration in the Power systems around the world, having in some countries a large contribution to the total energy production. In order to protect the distribution and transmission systems, the grid operators are more and more talking about the ability of the distribution systems (mainly wind turbines WT systems) to behave as a conventional Power plant. This paper discusses the possibilities of the Distributed Power Generation systems (DPGS) to deliver Power when grid disturbances are present in the utility network. The focus is set more on the control strategies for active Power Generation, and mainly on the creation of the reference currents which fulfill the demanded output Power. Considerations about reactive Power are also stated. Experimental results are presented in order to validate the theory behind the proposed control strategies on faulty grid

  • pll algorithm for Power Generation systems robust to grid voltage faults
    Power Electronics Specialists Conference, 2006
    Co-Authors: Adrian V. Timbus, Marco Liserre, Frede Blaabjerg, T Teodorescu, Paul Rodriguez
    Abstract:

    In the case of unbalanced grid faults, one of the main problems for the Distributed Power Generation Systems (DPGSs) controller is the second harmonic ripple in the control, consequence of the phase unbalance caused by the fault. The second harmonic propagates into different sections of the controller and can have a negative influence on the controller even leading to trip out of the system. This paper proposes a novel Phase-Looked Loop (PLL) algorithm which is able to filter out the negative sequence and to provide a clean synchronization signal. Along with the conventional PI controller in the PLL structure, the proposed algorithm employs a repetitive controller to deal with the second harmonic. The purpose of the repetitive controller is to amplify the second harmonic in the reference of the PI controller, so that this can be better rejected. Simulation and experimental results are used to validate the robustness of the proposed system when running on grid faults.

Frede Blaabjerg - One of the best experts on this subject based on the ideXlab platform.

  • Distributed Power Generation systems and protection
    Proceedings of the IEEE, 2017
    Co-Authors: Frede Blaabjerg, Yongheng Yang, Dongsheng Yang, Xiongfei Wang
    Abstract:

    Continuously expanding deployments of Distributed Power-Generation systems (DPGSs) are transforming the conventional centralized Power grid into a mixed Distributed electrical network. The modern Power grid requires flexible energy utilization but presents challenges in the case of a high penetration degree of renewable energy, among which wind and solar photovoltaics are typical sources. The integration level of the DPGS into the grid plays a critical role in developing sustainable and resilient Power systems, especially with highly intermittent renewable energy resources. To address the challenging issues and, more importantly, to leverage the energy Generation, stringent demands from both utility operators and consumers have been imposed on the DPGS. Furthermore, as the core of energy conversion, numerous Power electronic converters employing advanced control techniques have been developed for the DPGS to consolidate the integration. In light of the above, this paper reviews the Power-conversion and control technologies used for DPGSs. The impacts of the DPGS on the Distributed grid are also examined, and more importantly, strategies for enhancing the connection and protection of the DPGS are discussed.

  • benchmarking of voltage sag generators
    Conference of the Industrial Electronics Society, 2012
    Co-Authors: Yongheng Yang, Frede Blaabjerg, Zhixiang Zou
    Abstract:

    The increased penetration of renewable energy systems, like photovoltaic and wind Power systems, rises the concern about the Power quality and stability of the utility grid. Some regulations for Low Voltage Ride-Through (LVRT) for medium voltage or high voltage applications, are coming into force to guide these grid-connected Distributed Power Generation systems. In order to verify the response of such systems for voltage disturbance, mainly for evaluation of voltage sags/dips, a Voltage Sag Generator (VSG) is needed. This paper evaluates such sag test devices according to IEC 61000 in order to provide cheaper solutions to test against voltage sags. Simulation and experimental results demonstrate that the shunt impedance based VSG solution is the easiest and cheapest one for laboratory test applications. The back-to-back fully controlled converter based VSG is the most flexible solution for the system test under grid faults but also the most expensive one.

  • evaluation of current controllers for Distributed Power Generation systems
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    This paper discusses the evaluation of different current controllers employed for grid-connected Distributed Power Generation systems having variable input Power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation is also presented. Since the paper discusses the implementation of these controllers for grid-connected applications, their evaluation is made in three operating conditions. First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input Power variations and grid voltage faults is also examined. Experimental results in each case are presented in order to evaluate the performance of the controllers.

  • flexible active Power control of Distributed Power Generation systems during grid faults
    IEEE Transactions on Industrial Electronics, 2007
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Frede Blaabjerg
    Abstract:

    The increasing penetration of Distributed Power Generation into the Power system leads to a continuous evolution of grid interconnection requirements. In particular, active Power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active Power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.

  • independent pq control for Distributed Power Generation systems under grid faults
    Conference of the Industrial Electronics Society, 2006
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Marco Liserre, R Teodeorescu, Frede Blaabjerg
    Abstract:

    This work aims to present a generalized vector-based formulation for calculating the grid-side current reference of Distributed Power Generation systems in order to independently control active and reactive Power delivered to the grid. Strategies for current reference Generation were implemented on the abc stationary reference frame and their effectiveness was demonstrated experimentally, perhaps validating the theoretical analysis even under grid fault conditions.

Masoud Aliakbar Golkar - One of the best experts on this subject based on the ideXlab platform.

  • control of hybrid fuel cell energy storage Distributed Generation system against voltage sag
    International Journal of Electrical Power & Energy Systems, 2010
    Co-Authors: Amin Hajizadeh, Masoud Aliakbar Golkar
    Abstract:

    Fuel cell (FC) and energy storage (ES) based hybrid Distributed Power Generation systems appear to be very promising for satisfying high energy and high Power requirements of Power quality problems in Distributed Generation (DG) systems. In this study, design of control strategy for hybrid fuel cell/energy storage Distributed Power Generation system during voltage sag has been presented. The proposed control strategy allows hybrid Distributed Generation system works properly when a voltage disturbance occurs in distribution system and hybrid system stays connected to the main grid. Hence, modeling, controller design, and simulation study of a hybrid Distributed Generation system are investigated. The physical model of the fuel cell stack, energy storage and the models of Power conditioning units are described. Then the control design methodology for each component of the hybrid system is proposed. Simulation results are given to show the overall system performance including active Power control and voltage sag ride-through capability of the hybrid Distributed Generation system.

  • fuzzy neural control of a hybrid fuel cell battery Distributed Power Generation system
    Iet Renewable Power Generation, 2009
    Co-Authors: Amin Hajizadeh, Masoud Aliakbar Golkar
    Abstract:

    An innovative control strategy is proposed of hybrid Distributed Generation (HDG) systems, including solid oxide fuel cell (SOFC) as the main energy source and battery energy storage as the auxiliary Power source. The overall configuration of the HDG system is given, and dynamic models for the SOFC Power plant, battery bank and its Power electronic interfacing are briefly described, and controller design methodologies for the Power conditioning units and fuel cell to control the Power flow from the hybrid Power plant to the utility grid are presented. To distribute the Power between Power sources, the fuzzy switching controller has been developed. Then, a Lyapunov based-neuro fuzzy algorithm is presented for designing the controllers of fuel cell Power plant, DC/DC and DC/AC converters; to regulate the input fuel flow and meet a desirable output Power demand. Simulation results are given to show the overall system performance including load-following and Power management of the system.

Marco Liserre - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of current controllers for Distributed Power Generation systems
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    This paper discusses the evaluation of different current controllers employed for grid-connected Distributed Power Generation systems having variable input Power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation is also presented. Since the paper discusses the implementation of these controllers for grid-connected applications, their evaluation is made in three operating conditions. First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input Power variations and grid voltage faults is also examined. Experimental results in each case are presented in order to evaluate the performance of the controllers.

  • flexible active Power control of Distributed Power Generation systems during grid faults
    IEEE Transactions on Industrial Electronics, 2007
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Frede Blaabjerg
    Abstract:

    The increasing penetration of Distributed Power Generation into the Power system leads to a continuous evolution of grid interconnection requirements. In particular, active Power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active Power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.

  • independent pq control for Distributed Power Generation systems under grid faults
    Conference of the Industrial Electronics Society, 2006
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Marco Liserre, R Teodeorescu, Frede Blaabjerg
    Abstract:

    This work aims to present a generalized vector-based formulation for calculating the grid-side current reference of Distributed Power Generation systems in order to independently control active and reactive Power delivered to the grid. Strategies for current reference Generation were implemented on the abc stationary reference frame and their effectiveness was demonstrated experimentally, perhaps validating the theoretical analysis even under grid fault conditions.

  • Control Strategies for Distributed Power Generation Systems Operating on Faulty Grid
    2006 IEEE International Symposium on Industrial Electronics, 2006
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    The Distributed Power Generation based on renewable energy sources such as wind and sun experiences a high penetration in the Power systems around the world, having in some countries a large contribution to the total energy production. In order to protect the distribution and transmission systems, the grid operators are more and more talking about the ability of the distribution systems (mainly wind turbines WT systems) to behave as a conventional Power plant. This paper discusses the possibilities of the Distributed Power Generation systems (DPGS) to deliver Power when grid disturbances are present in the utility network. The focus is set more on the control strategies for active Power Generation, and mainly on the creation of the reference currents which fulfill the demanded output Power. Considerations about reactive Power are also stated. Experimental results are presented in order to validate the theory behind the proposed control strategies on faulty grid

  • pll algorithm for Power Generation systems robust to grid voltage faults
    Power Electronics Specialists Conference, 2006
    Co-Authors: Adrian V. Timbus, Marco Liserre, Frede Blaabjerg, T Teodorescu, Paul Rodriguez
    Abstract:

    In the case of unbalanced grid faults, one of the main problems for the Distributed Power Generation Systems (DPGSs) controller is the second harmonic ripple in the control, consequence of the phase unbalance caused by the fault. The second harmonic propagates into different sections of the controller and can have a negative influence on the controller even leading to trip out of the system. This paper proposes a novel Phase-Looked Loop (PLL) algorithm which is able to filter out the negative sequence and to provide a clean synchronization signal. Along with the conventional PI controller in the PLL structure, the proposed algorithm employs a repetitive controller to deal with the second harmonic. The purpose of the repetitive controller is to amplify the second harmonic in the reference of the PI controller, so that this can be better rejected. Simulation and experimental results are used to validate the robustness of the proposed system when running on grid faults.

Remus Teodorescu - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of current controllers for Distributed Power Generation systems
    IEEE Transactions on Power Electronics, 2009
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    This paper discusses the evaluation of different current controllers employed for grid-connected Distributed Power Generation systems having variable input Power, such as wind turbines and photovoltaic systems. The focus is mainly set on linear controllers such as proportional-integral, proportional-resonant, and deadbeat (DB) controllers. Additionally, an improved DB controller robust against grid impedance variation is also presented. Since the paper discusses the implementation of these controllers for grid-connected applications, their evaluation is made in three operating conditions. First, in steady-state conditions, the contribution of controllers to the total harmonic distortion of the grid current is pursued. Further on, the behavior of controllers in the case of transient conditions like input Power variations and grid voltage faults is also examined. Experimental results in each case are presented in order to evaluate the performance of the controllers.

  • flexible active Power control of Distributed Power Generation systems during grid faults
    IEEE Transactions on Industrial Electronics, 2007
    Co-Authors: Pedro Rodriguez, Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Frede Blaabjerg
    Abstract:

    The increasing penetration of Distributed Power Generation into the Power system leads to a continuous evolution of grid interconnection requirements. In particular, active Power control will play an important role both during grid faults (low-voltage ride-through capability and controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active Power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.

  • Control Strategies for Distributed Power Generation Systems Operating on Faulty Grid
    2006 IEEE International Symposium on Industrial Electronics, 2006
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Marco Liserre, Pedro Rodriguez, Frede Blaabjerg
    Abstract:

    The Distributed Power Generation based on renewable energy sources such as wind and sun experiences a high penetration in the Power systems around the world, having in some countries a large contribution to the total energy production. In order to protect the distribution and transmission systems, the grid operators are more and more talking about the ability of the distribution systems (mainly wind turbines WT systems) to behave as a conventional Power plant. This paper discusses the possibilities of the Distributed Power Generation systems (DPGS) to deliver Power when grid disturbances are present in the utility network. The focus is set more on the control strategies for active Power Generation, and mainly on the creation of the reference currents which fulfill the demanded output Power. Considerations about reactive Power are also stated. Experimental results are presented in order to validate the theory behind the proposed control strategies on faulty grid

  • adaptive resonant controller for grid connected converters in Distributed Power Generation systems
    Applied Power Electronics Conference, 2006
    Co-Authors: Adrian V. Timbus, Remus Teodorescu, Mihai Ciobotaru, Frede Blaabjerg
    Abstract:

    Due to its superior performance when regulating sinusoidal waveforms and the possibility to compensate for low order harmonics by means of harmonic compensator (HC), proportional resonant (PR) controller is a real alternative to the conventional proportional integral (PI) controller, when implemented in a grid connected system like Distributed Power Generation systems (DPGS). Anyway, both PR and HC necessitate the resonant frequency value inside their internal model. Normally, the nominal value of the grid frequency and its multiples are used, but in the case when the grid frequency experiences fluctuations, the performance of both PR and HC is diminished. This paper discuss the possibility of improving the behavior of resonant controller and harmonic compensator in the case of grid frequency variations. The proposed solution makes use of the frequency information provided by the phase-locked loop (PLL) system already used in most of DPGS today. Experimental results are presented in order to validate the proposed solution and it shows to work very well.

  • Overview of control and grid synchronization for Distributed Power Generation systems
    IEEE Transactions on Industrial Electronics, 2006
    Co-Authors: Remus Teodorescu, Marco Liserre, Adrian V. Timbus
    Abstract:

    Renewable energy sources like wind, sun, and hydro are seen as a reliable alternative to the traditional energy sources such as oil, natural gas, or coal. Distributed Power Generation systems (DPGSs) based on renewable energy sources experience a large development worldwide, with Germany, Denmark, Japan, and USA as leaders in the development in this field. Due to the increasing number of DPGSs connected to the utility network, new and stricter standards in respect to Power quality, safe running, and islanding protection are issued. As a consequence, the control of Distributed Generation systems should be improved to meet the requirements for grid interconnection. This paper gives an overview of the structures for the DPGS based on fuel cell, photovoltaic, and wind turbines. In addition, control structures of the grid-side converter are presented, and the possibility of compensation for low-order harmonics is also discussed. Moreover, control strategies when running on grid faults are treated. This paper ends up with an overview of synchronization methods and a discussion about their importance in the control