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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Mon, 30 Nov 2020 05:41:43 GMT2020-11-30T05:41:43ZCritical clearing time determination and enhancement of grid-forming converters embedding virtual impedance as current limitation algorithm
http://hdl.handle.net/10985/17951
Critical clearing time determination and enhancement of grid-forming converters embedding virtual impedance as current limitation algorithm
QORIA, Taoufik; GRUSON, François; COLAS, Frédéric; DENIS, Guillaume; PREVOST, Thibault; GUILLAUD, Xavier
The present paper deals with the post-fault synchronization of a voltage source converter based on the droop control. In case of large disturbances on the grid, the current is limited via current limitation algorithms such as the virtual impedance. During the fault, the power converter internal frequency deviates resulting in a converter angle divergence. Thereby, the system may lose the synchronism after fault clearing and which may lead to instability. Hence, this paper proposes a theoretical approach to explain the dynamic behavior of the grid forming converter subject to a three phase bolted fault. A literal expression of the critical clearing time is defined. Due to the precise analysis of the phenomenon, a simple algorithm can be derived to enhance the transient stability. It is based on adaptive gain included in the droop control. These objectives have been achieved with no external information and without switching from one control to the other. To prove the effectiveness of the developed control, experimental test cases have been performed in different faulted conditions.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/179512019-01-01T00:00:00ZQORIA, TaoufikGRUSON, FrançoisCOLAS, FrédéricDENIS, GuillaumePREVOST, ThibaultGUILLAUD, XavierThe present paper deals with the post-fault synchronization of a voltage source converter based on the droop control. In case of large disturbances on the grid, the current is limited via current limitation algorithms such as the virtual impedance. During the fault, the power converter internal frequency deviates resulting in a converter angle divergence. Thereby, the system may lose the synchronism after fault clearing and which may lead to instability. Hence, this paper proposes a theoretical approach to explain the dynamic behavior of the grid forming converter subject to a three phase bolted fault. A literal expression of the critical clearing time is defined. Due to the precise analysis of the phenomenon, a simple algorithm can be derived to enhance the transient stability. It is based on adaptive gain included in the droop control. These objectives have been achieved with no external information and without switching from one control to the other. To prove the effectiveness of the developed control, experimental test cases have been performed in different faulted conditions.Tuning of Cascaded Controllers for Robust Grid-Forming Voltage Source Converter
http://hdl.handle.net/10985/14835
Tuning of Cascaded Controllers for Robust Grid-Forming Voltage Source Converter
QORIA, Taoufik; GRUSON, François; COLAS, Frédéric; GUILLAUD, Xavier; DEBRY, Marie-Sophie; PREVOST, Thierry
From the origin of the grid, energy has been delivered to electrical loads mainly by synchronous machines. All the main rules to manage the grid have been based on the electromechanical behavior of these machines which have been extensively studied for many years. Due to the increase of HVDC link and renewable energy sources as wind turbine and PV, power converters are massively introduced in the grid with a fundamentally different dynamic behavior. Some years ago, they were connected as simple power injector. Then, they were asked to provide some ancillary services to the grid, in the future, grid forming capability will be required. Even if grid-forming converters had been extensively studied for microgrids and offshore grids, it has to be adapted to transmission grid where the topology may be largely modified. This paper presents an algorithm for calculating the controller parameters of a grid-forming converter which guarantee a stable behavior for many different configurations of the grid.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/148352018-01-01T00:00:00ZQORIA, TaoufikGRUSON, FrançoisCOLAS, FrédéricGUILLAUD, XavierDEBRY, Marie-SophiePREVOST, ThierryFrom the origin of the grid, energy has been delivered to electrical loads mainly by synchronous machines. All the main rules to manage the grid have been based on the electromechanical behavior of these machines which have been extensively studied for many years. Due to the increase of HVDC link and renewable energy sources as wind turbine and PV, power converters are massively introduced in the grid with a fundamentally different dynamic behavior. Some years ago, they were connected as simple power injector. Then, they were asked to provide some ancillary services to the grid, in the future, grid forming capability will be required. Even if grid-forming converters had been extensively studied for microgrids and offshore grids, it has to be adapted to transmission grid where the topology may be largely modified. This paper presents an algorithm for calculating the controller parameters of a grid-forming converter which guarantee a stable behavior for many different configurations of the grid.Tuning of Cascaded Controllers for Robust Grid-Forming Voltage Source Converter
http://hdl.handle.net/10985/15938
Tuning of Cascaded Controllers for Robust Grid-Forming Voltage Source Converter
QORIA, Taoufik; GRUSON, François; COLAS, Frédéric; GUILLAUD, Xavier; DEBRY, Marie-Sophie; PREVOST, Thibault
From the origin of the grid, energy has been delivered to electrical loads mainly by synchronous machines. All the main rules to manage the grid have been based on the electromechanical behavior of these machines which have been extensively studied for many years. Due to the increase of HVDC link and renewable energy sources as wind turbine and PV, power converters are massively introduced in the grid with a fundamentally different dynamic behavior. Some years ago, they were connected as simple power injector. Then, they were asked to provide some ancillary services to the grid, in the future, grid forming capability will be required. Even if gridforming converters had been extensively studied for microgrids and offshore grids, it has to be adapted to transmission grid where the topology may be largely modified. This paper presents an algorithm for calculating the controller parameters of a gridforming converter which guarantee a stable behavior for many different configurations of the grid.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/159382018-01-01T00:00:00ZQORIA, TaoufikGRUSON, FrançoisCOLAS, FrédéricGUILLAUD, XavierDEBRY, Marie-SophiePREVOST, ThibaultFrom the origin of the grid, energy has been delivered to electrical loads mainly by synchronous machines. All the main rules to manage the grid have been based on the electromechanical behavior of these machines which have been extensively studied for many years. Due to the increase of HVDC link and renewable energy sources as wind turbine and PV, power converters are massively introduced in the grid with a fundamentally different dynamic behavior. Some years ago, they were connected as simple power injector. Then, they were asked to provide some ancillary services to the grid, in the future, grid forming capability will be required. Even if gridforming converters had been extensively studied for microgrids and offshore grids, it has to be adapted to transmission grid where the topology may be largely modified. This paper presents an algorithm for calculating the controller parameters of a gridforming converter which guarantee a stable behavior for many different configurations of the grid.Modeling and Control of the Modular Multilevel Converter connected to an inductive DC source using Energetic Macroscopic Representation
http://hdl.handle.net/10985/14717
Modeling and Control of the Modular Multilevel Converter connected to an inductive DC source using Energetic Macroscopic Representation
QORIA, Taoufik; GRUSON, François; DELARUE, Philippe; COLAS, Frédéric; GUILLAUD, Xavier; LE MOIGNE, Philippe
The use of DC transmission is particularly advantageous for long-distance transmission and interconnection of asynchronous AC networks. Several converter topologies can be used for HVDC. Multilevel Modular Converters (MMCs) are the most favored given their technological advantages over other converters topologies. Due to their industrial maturity, they have become essential for all AC / DC conversion. So far, they have always been studied with a voltage source on DC side. However, when the converter is equipped with DC breaker, a series inductor is associated to limit current variations. This has consequences in term of modeling and control determination. This article aims to propose a modification of the control law in order to take into account this inductor. To facilitate the control organization, the Energetic Macroscopic Representation (EMR) is used.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/147172018-01-01T00:00:00ZQORIA, TaoufikGRUSON, FrançoisDELARUE, PhilippeCOLAS, FrédéricGUILLAUD, XavierLE MOIGNE, PhilippeThe use of DC transmission is particularly advantageous for long-distance transmission and interconnection of asynchronous AC networks. Several converter topologies can be used for HVDC. Multilevel Modular Converters (MMCs) are the most favored given their technological advantages over other converters topologies. Due to their industrial maturity, they have become essential for all AC / DC conversion. So far, they have always been studied with a voltage source on DC side. However, when the converter is equipped with DC breaker, a series inductor is associated to limit current variations. This has consequences in term of modeling and control determination. This article aims to propose a modification of the control law in order to take into account this inductor. To facilitate the control organization, the Energetic Macroscopic Representation (EMR) is used.Effect of Using PLL-Based Grid-Forming Control on Active Power Dynamics Under Various SCR
http://hdl.handle.net/10985/16655
Effect of Using PLL-Based Grid-Forming Control on Active Power Dynamics Under Various SCR
ROKROK, Ebrahim; QORIA, Taoufik; BRUYERE, Antoine; BRUNO, François; GUILLAUD, X.
This paper investigates the effect of using phaselocked loop (PLL) on the performance of a grid-forming controlled converter. Usually, a grid-forming controlled converter operates without dedicated PLL. It is shown that in this case, the active power dominant dynamics are highly dependent to the grid short circuit ratio (SCR). In case of using PLL, the obtained results illustrate that the SCR has a negligible effect on the dynamic behavior of the system. Moreover, the power converter will not participate to the frequency regulation anymore; therefore, the converter response time can be adjusted independently to the choice of the droop control gain, which is not possible without PLL. A simple equivalent model is presented which gives a physical explanation of these features.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/166552019-01-01T00:00:00ZROKROK, EbrahimQORIA, TaoufikBRUYERE, AntoineBRUNO, FrançoisGUILLAUD, X.This paper investigates the effect of using phaselocked loop (PLL) on the performance of a grid-forming controlled converter. Usually, a grid-forming controlled converter operates without dedicated PLL. It is shown that in this case, the active power dominant dynamics are highly dependent to the grid short circuit ratio (SCR). In case of using PLL, the obtained results illustrate that the SCR has a negligible effect on the dynamic behavior of the system. Moreover, the power converter will not participate to the frequency regulation anymore; therefore, the converter response time can be adjusted independently to the choice of the droop control gain, which is not possible without PLL. A simple equivalent model is presented which gives a physical explanation of these features.Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter
http://hdl.handle.net/10985/17101
Coupling Influence on the dq Impedance Stability Analysis for the Three-Phase Grid-Connected Inverter
LI, Chuanyue; QORIA, Taoufik; COLAS, Frédéric; JUN, Liang; WENLONG, Ming; GRUSON, François; GUILLAUD, X.
The dq impedance stability analysis for a grid-connected current-control inverter is based on the impedance ratio matrix. However, the coupled matrix brings difficulties in deriving its eigenvalues for the analysis based on the general Nyquist criterion. If the couplings are ignored for simplification, unacceptable errors will be present in the analysis. In this paper, the influence of the couplings on the dq impedance stability analysis is studied. To take the couplings into account simply, the determinant-based impedance stability analysis is used. The mechanism between the determinant of the impedance-ratio matrix and the inverter stability is unveiled. Compared to the eigenvalues-based analysis, only one determinant rather than two eigenvalue s-function is required for the stability analysis. One Nyquist plot or pole map can be applied to the determinant to check the right-half-plane poles. The accuracy of the determinant-based stability analysis is also checked by comparing with the state-space stability analysis method. For the stability analysis, the coupling influence on the current control, the phase-locked loop, and the grid impedance are studied. The errors can be 10% in the stability analysis if the couplings are ignored.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/171012019-01-01T00:00:00ZLI, ChuanyueQORIA, TaoufikCOLAS, FrédéricJUN, LiangWENLONG, MingGRUSON, FrançoisGUILLAUD, X.The dq impedance stability analysis for a grid-connected current-control inverter is based on the impedance ratio matrix. However, the coupled matrix brings difficulties in deriving its eigenvalues for the analysis based on the general Nyquist criterion. If the couplings are ignored for simplification, unacceptable errors will be present in the analysis. In this paper, the influence of the couplings on the dq impedance stability analysis is studied. To take the couplings into account simply, the determinant-based impedance stability analysis is used. The mechanism between the determinant of the impedance-ratio matrix and the inverter stability is unveiled. Compared to the eigenvalues-based analysis, only one determinant rather than two eigenvalue s-function is required for the stability analysis. One Nyquist plot or pole map can be applied to the determinant to check the right-half-plane poles. The accuracy of the determinant-based stability analysis is also checked by comparing with the state-space stability analysis method. For the stability analysis, the coupling influence on the current control, the phase-locked loop, and the grid impedance are studied. The errors can be 10% in the stability analysis if the couplings are ignored.Critical clearing time determination and enhancement of grid-forming converters embedding virtual impedance as current limitation algorithm
http://hdl.handle.net/10985/17729
Critical clearing time determination and enhancement of grid-forming converters embedding virtual impedance as current limitation algorithm
QORIA, Taoufik; GRUSON, François; COLAS, Frédéric; DENIS, Guillaume; PREVOST, Thibault; GUILLAUD, Xavier
The present paper deals with the post-fault synchronization of a voltage source converter based on the droop control. In case of large disturbances on the grid, the current is limited via current limitation algorithms such as the virtual impedance. During the fault, the power converter internal frequency deviates resulting in a converter angle divergence. Thereby, the system may lose the synchronism after fault clearing and which may lead to instability. Hence, this paper proposes a theoretical approach to explain the dynamic behavior of the grid forming converter subject to a three phase bolted fault. A literal expression of the critical clearing time is defined. Due to the precise analysis of the phenomenon, a simple algorithm can be derived to enhance the transient stability. It is based on adaptive gain included in the droop control. These objectives have been achieved with no external information and without switching from one control to the other. To prove the effectiveness of the developed control, experimental test cases have been performed in different faulted conditions.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/177292019-01-01T00:00:00ZQORIA, TaoufikGRUSON, FrançoisCOLAS, FrédéricDENIS, GuillaumePREVOST, ThibaultGUILLAUD, XavierThe present paper deals with the post-fault synchronization of a voltage source converter based on the droop control. In case of large disturbances on the grid, the current is limited via current limitation algorithms such as the virtual impedance. During the fault, the power converter internal frequency deviates resulting in a converter angle divergence. Thereby, the system may lose the synchronism after fault clearing and which may lead to instability. Hence, this paper proposes a theoretical approach to explain the dynamic behavior of the grid forming converter subject to a three phase bolted fault. A literal expression of the critical clearing time is defined. Due to the precise analysis of the phenomenon, a simple algorithm can be derived to enhance the transient stability. It is based on adaptive gain included in the droop control. These objectives have been achieved with no external information and without switching from one control to the other. To prove the effectiveness of the developed control, experimental test cases have been performed in different faulted conditions.Tuning of AC voltage-controlled VSC based Linear Quadratic Regulation
http://hdl.handle.net/10985/15936
Tuning of AC voltage-controlled VSC based Linear Quadratic Regulation
QORIA, Taoufik; LI, Chuanyue; OUE, Ko; GRUSON, François; COLAS, Frédéric; GUILLAUD, Xavier; PREVOST, Thibault
In the near future, power converters will be massively introduced in transmission grids due to renewable energy sources and high voltage direct current (HVDC) increase. Voltage Source Converter (VSC) control laws assume that Synchronous Generators (SGs) build a stiff AC voltage which allows the synchronization of converters. This is one of the major reasons that limit the high integration of currentsource converters in transmission grid. This constraint is no longer relevant when power converters operate as a voltage source based on the grid-forming concept. This concept uses an inner cascaded PI controllers in order to regulate the output AC voltage. However, it is difficult to tune its controller parameters for stable operation in grid-connected mode. This paper proposes an alternative state-feedback control with integral compensator based linear quadratic regulation (LQR) in order to ensure a stable operation and to get a better AC voltage transient and good decoupling between reactive and active power. The proposed control will be fully analyzed and compared to conventional methods.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/159362019-01-01T00:00:00ZQORIA, TaoufikLI, ChuanyueOUE, KoGRUSON, FrançoisCOLAS, FrédéricGUILLAUD, XavierPREVOST, ThibaultIn the near future, power converters will be massively introduced in transmission grids due to renewable energy sources and high voltage direct current (HVDC) increase. Voltage Source Converter (VSC) control laws assume that Synchronous Generators (SGs) build a stiff AC voltage which allows the synchronization of converters. This is one of the major reasons that limit the high integration of currentsource converters in transmission grid. This constraint is no longer relevant when power converters operate as a voltage source based on the grid-forming concept. This concept uses an inner cascaded PI controllers in order to regulate the output AC voltage. However, it is difficult to tune its controller parameters for stable operation in grid-connected mode. This paper proposes an alternative state-feedback control with integral compensator based linear quadratic regulation (LQR) in order to ensure a stable operation and to get a better AC voltage transient and good decoupling between reactive and active power. The proposed control will be fully analyzed and compared to conventional methods.Power Converters Classification and Characterization in Power Transmission Systems
http://hdl.handle.net/10985/15937
Power Converters Classification and Characterization in Power Transmission Systems
QORIA, Taoufik; PREVOST, Thibault; DENIS, Guillaume; GRUSON, François; COLAS, Frédéric; GUILLAUD, Xavier
Because of the throng of control strategies based Voltage Source Converters (VSC) recently proposed in the literature; their classification and characterization are becoming a trending topic. The high similarities of the proposed control strategies may lead to confusions and a misunderstanding of vocabulary. Therefore, this paper seeks first to highlight the possible features fulfilled by power converters in a large power system. The combination of these features is used to classify power converters. Furthermore, power converters can be seen by a power transmission system operators as black boxes, and they may have the same inputs and outputs, which makes their characterizations more difficult. This paper looks to show that only the fundamental nature of the source has an influence on the system dynamic behavior, thus, power converter can be characterized from their transient behavior in response to grid disturbances.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/159372019-01-01T00:00:00ZQORIA, TaoufikPREVOST, ThibaultDENIS, GuillaumeGRUSON, FrançoisCOLAS, FrédéricGUILLAUD, XavierBecause of the throng of control strategies based Voltage Source Converters (VSC) recently proposed in the literature; their classification and characterization are becoming a trending topic. The high similarities of the proposed control strategies may lead to confusions and a misunderstanding of vocabulary. Therefore, this paper seeks first to highlight the possible features fulfilled by power converters in a large power system. The combination of these features is used to classify power converters. Furthermore, power converters can be seen by a power transmission system operators as black boxes, and they may have the same inputs and outputs, which makes their characterizations more difficult. This paper looks to show that only the fundamental nature of the source has an influence on the system dynamic behavior, thus, power converter can be characterized from their transient behavior in response to grid disturbances.Development of a power hardware in the loop simulation of an islanded microgrid
http://hdl.handle.net/10985/17100
Development of a power hardware in the loop simulation of an islanded microgrid
FAKHAM, Hicham; QORIA, Taoufik; LEGRY, Martin; DUCARME, Olivier; COLAS, Frédéric
In this paper a Power Hardware in the loop simulation has been realized to test in a safely way the performances and reliability of a device called “PowerCorner” used to supply an islanded microgrid. A real-time model has been developed in order to simulate the microgrid, batteries and photovoltaic panels. Some modeling criterions have been proposed to reduce time-step simulation and enhancing the Power Hardware in the loop simulation stability. Power Hardware in the loop simulation is used to emulate the AC and DC environments around the power inverters. On the DC side, DC power amplifier is used to emulate photovoltaic power plants and storage devices made on Lithium batteries. On the AC side, AC power amplifier is used to emulate the behavior of the microgrid. These two power amplifiers are controlled by a digital real time simulator which embeds the dynamic behavior of both DC and AC sides.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/171002019-01-01T00:00:00ZFAKHAM, HichamQORIA, TaoufikLEGRY, MartinDUCARME, OlivierCOLAS, FrédéricIn this paper a Power Hardware in the loop simulation has been realized to test in a safely way the performances and reliability of a device called “PowerCorner” used to supply an islanded microgrid. A real-time model has been developed in order to simulate the microgrid, batteries and photovoltaic panels. Some modeling criterions have been proposed to reduce time-step simulation and enhancing the Power Hardware in the loop simulation stability. Power Hardware in the loop simulation is used to emulate the AC and DC environments around the power inverters. On the DC side, DC power amplifier is used to emulate photovoltaic power plants and storage devices made on Lithium batteries. On the AC side, AC power amplifier is used to emulate the behavior of the microgrid. These two power amplifiers are controlled by a digital real time simulator which embeds the dynamic behavior of both DC and AC sides.