https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 13 Apr 2026 02:52:29 GMT 2026-04-13T02:52:29Z http://hdl.handle.net/10985/15938 Tuning of Cascaded Controllers for Robust Grid-Forming Voltage Source Converter QORIA, Taoufik; 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 GMT http://hdl.handle.net/10985/15938 2018-01-01T00:00:00Z QORIA, Taoufik 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. 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; 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 GMT http://hdl.handle.net/10985/14717 2018-01-01T00:00:00Z QORIA, Taoufik 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. http://hdl.handle.net/10985/14838 Contrôle du Convertisseur Modulaire Multiniveaux connecté à une source DC inductive QORIA, Taoufik; DELARUE, Philippe; COLAS, Frédéric; LE MOIGNE, Philippe; GUILLAUD, X. L'utilisation de la transmission DC est particulièrement avantageuse pour la transmission à longue distance et l'interconnexion des réseaux AC asynchrones. Plusieurs topologies de convertisseur peuvent être utilisées pour le HVDC. Les convertisseurs modulaires multiniveaux (MMC) sont les plus favorisés étant donné leurs avantages technologiques par rapport aux autres topologies de convertisseurs. Du fait de leur maturité industrielle, ils se sont imposés maintenant pour tous les convertisseurs AC/DC à transistors de forte puissance. Jusqu'ici, ils ont toujours été étudiés avec une source de tension côté DC. Or, lorsqu'ils sont équipés de DC breaker, on associe une inductance en série pour limiter les variations de courant. Ceci a des conséquences en terme de modélisation puis de détermination de la commande. Cet article a pour objectif de proposer une modification de commande afin de prendre en compte cette inductance. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/14838 2018-01-01T00:00:00Z QORIA, Taoufik DELARUE, Philippe COLAS, Frédéric LE MOIGNE, Philippe GUILLAUD, X. L'utilisation de la transmission DC est particulièrement avantageuse pour la transmission à longue distance et l'interconnexion des réseaux AC asynchrones. Plusieurs topologies de convertisseur peuvent être utilisées pour le HVDC. Les convertisseurs modulaires multiniveaux (MMC) sont les plus favorisés étant donné leurs avantages technologiques par rapport aux autres topologies de convertisseurs. Du fait de leur maturité industrielle, ils se sont imposés maintenant pour tous les convertisseurs AC/DC à transistors de forte puissance. Jusqu'ici, ils ont toujours été étudiés avec une source de tension côté DC. Or, lorsqu'ils sont équipés de DC breaker, on associe une inductance en série pour limiter les variations de courant. Ceci a des conséquences en terme de modélisation puis de détermination de la commande. Cet article a pour objectif de proposer une modification de commande afin de prendre en compte cette inductance. http://hdl.handle.net/10985/14715 Inertia effect and load sharing capability of grid forming converters connected to a transmission grid QORIA, Taoufik; COLAS, Frédéric; DENIS, Guillaume; PREVOST, T.; GUILLAUD, Xavier The virtual synchronous machine concept (VSM) has been developed initially to reproduce the synchronous machine stabilizing effect by providing inertia with the emulation of swing equation, whereas droop control is developed initially to ensure load sharing and has no inertia. An introduction of a low pass filter to droop control has been motivated to filter the active power measurement and ensures a time decoupling with the inner control loops, whereas, this low-pass filter can also provide inertia to the system. This functionality is limited due to its negative impact on the active power dynamic. This paper proposes an analysis of the conventional droop control by showing its limitations and proposes an improved inertial droop control that allows providing the inertia to the system and ensures a good dynamic behavior of the active power at once in simple manner, and without modifying the load sharing capability. The results obtained are compared to the conventional method (Droop control and VSM) in various topologies in order to show the relevance of the proposed method. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/14715 2019-01-01T00:00:00Z QORIA, Taoufik COLAS, Frédéric DENIS, Guillaume PREVOST, T. GUILLAUD, Xavier The virtual synchronous machine concept (VSM) has been developed initially to reproduce the synchronous machine stabilizing effect by providing inertia with the emulation of swing equation, whereas droop control is developed initially to ensure load sharing and has no inertia. An introduction of a low pass filter to droop control has been motivated to filter the active power measurement and ensures a time decoupling with the inner control loops, whereas, this low-pass filter can also provide inertia to the system. This functionality is limited due to its negative impact on the active power dynamic. This paper proposes an analysis of the conventional droop control by showing its limitations and proposes an improved inertial droop control that allows providing the inertia to the system and ensures a good dynamic behavior of the active power at once in simple manner, and without modifying the load sharing capability. The results obtained are compared to the conventional method (Droop control and VSM) in various topologies in order to show the relevance of the proposed method. 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; 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 GMT http://hdl.handle.net/10985/17729 2019-01-01T00:00:00Z QORIA, Taoufik 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. 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; COLAS, Frédéric; DENIS, Guillaume; PREVOST, Thibault; GUILLAUD, Xavier; GRUSON, Francois 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 GMT http://hdl.handle.net/10985/17951 2019-01-01T00:00:00Z QORIA, Taoufik COLAS, Frédéric DENIS, Guillaume PREVOST, Thibault GUILLAUD, Xavier GRUSON, Francois 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. 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; GUILLAUD, X.; GRUSON, Francois 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 GMT http://hdl.handle.net/10985/17101 2019-01-01T00:00:00Z LI, Chuanyue QORIA, Taoufik COLAS, Frédéric JUN, Liang WENLONG, Ming GUILLAUD, X. GRUSON, Francois 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. 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 GMT http://hdl.handle.net/10985/17100 2019-01-01T00:00:00Z 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. 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 GMT http://hdl.handle.net/10985/16655 2019-01-01T00:00:00Z 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. http://hdl.handle.net/10985/15936 Tuning of AC voltage-controlled VSC based Linear Quadratic Regulation QORIA, Taoufik; LI, Chuanyue; OUE, Ko; 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 GMT http://hdl.handle.net/10985/15936 2019-01-01T00:00:00Z QORIA, Taoufik LI, Chuanyue OUE, Ko 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.