https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 15 May 2026 01:18:25 GMT 2026-05-15T01:18:25Z 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/10985/17729 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/10985/15936 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. http://hdl.handle.net/10985/15937 Power Converters Classification and Characterization in Power Transmission Systems QORIA, Taoufik; PREVOST, Thibault; DENIS, Guillaume; 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 GMT http://hdl.handle.net/10985/15937 2019-01-01T00:00:00Z QORIA, Taoufik PREVOST, Thibault DENIS, Guillaume 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.