EPE Association: EPE 2020 - DS1g-1: Power Electronics in Transmission and Distribution Systems-1

EPE 2020 - DS1g-1: Power Electronics in Transmission and Distribution Systems-1
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1g-1: Power Electronics in Transmission and Distribution Systems-1

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   Analysis of the coupling between the outer and inner control loops of a Grid-forming Voltage Source Converter
By Taoufik QORIA [View]
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Abstract: The question of grid forming control is very different depending on the connection to a low voltage or high voltage grid. In case of higher power application, the low switching frequency may induce some stability issues. This question has been studied and some solutions have been proposed through new inner current and voltage control tuning methods. However, the possible interactions between the inner and the outer controls have not been discussed yet. Actually, in large power system, the phasor modeling approximation is used in order to ease the analysis and reduce the time computations. It assumes a good decoupling between the control loops, which allows neglecting the inner loop dynamics. This paper investigates the effectiveness of this assumption by taking some examples of tuning methods proposed in the literature and showing the ability of each method to guarantee the decoupling between controllers. In this paper, small-signal analysis tool, participation factors and parametric sensitivities are used.

   Impact of grid-forming control on the internal energy of a modular multi-level converter
By Ebrahim ROKROK [View]
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Abstract: This paper presents a comparative analysis regarding the dynamic behavior of a Modular Multi-level Converter (MMC) with grid-forming control either with or without controlling the MMC internal energy. It has been demonstrated that the internal energy of the MMC in low-level control interacts with the high-level control, which is performed by a grid-forming scheme. In case of controlling the internal energy of the MMC, this interaction is mitigated. Moreover, it has been shown that the dynamic behavior of a grid-forming controlled MMC with internal energy control is identical to an equivalent 2-level Voltage Source Converter (VSC).

   Improved SoC Balancing and Active Power Sharing Control Method in Highly Resistive Line Microgrid
By Yuanhao ZHU [View]
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Abstract: This paper proposes a distributed control method for AC microgrid with high resistance lines, where P-V droop control modified by average SoC obtained through the SoC average estimator to guarantee the SoC balancing and active power sharing. The results of simulations verify the effectiveness of the proposed method.

   Rapid Impedance Estimation Algorithm for Mitigation of Synchronization Instability of Paralleled Converters under Grid Faults
By Mads TAUL [View]
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Abstract: Paralleled grid-connected converters operated as grid-following structures are vulnerable to transient synchronization instability during grid faults. This paper mathematically describes the instability phenomenon of paralleled converters and why it is more pronounced than for single-converter operation. Based on this model, instability can be averted by modifying each converter current reference depending on the external network impedance where asymptotic stability is proven. A rapid impedance estimation algorithm is presented, which can extract the network impedance based on the disturbance of the grid fault. This estimation is used to accurately adjust the converter current references in order to guarantee stability of all paralleled converters for any severity of the grid fault. The proposed control structure is verified in a detailed simulation study and through experimental tests, which demonstrate its potential and robustness.

EPE 2020 - DS1g-1: Power Electronics in Transmission and Distribution Systems-1
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1g-1: Power Electronics in Transmission and Distribution Systems-1
	[return to parent folder]

	Analysis of the coupling between the outer and inner control loops of a Grid-forming Voltage Source Converter By Taoufik QORIA	[View] [Download]
Abstract: The question of grid forming control is very different depending on the connection to a low voltage or high voltage grid. In case of higher power application, the low switching frequency may induce some stability issues. This question has been studied and some solutions have been proposed through new inner current and voltage control tuning methods. However, the possible interactions between the inner and the outer controls have not been discussed yet. Actually, in large power system, the phasor modeling approximation is used in order to ease the analysis and reduce the time computations. It assumes a good decoupling between the control loops, which allows neglecting the inner loop dynamics. This paper investigates the effectiveness of this assumption by taking some examples of tuning methods proposed in the literature and showing the ability of each method to guarantee the decoupling between controllers. In this paper, small-signal analysis tool, participation factors and parametric sensitivities are used.

	Impact of grid-forming control on the internal energy of a modular multi-level converter By Ebrahim ROKROK	[View] [Download]
Abstract: This paper presents a comparative analysis regarding the dynamic behavior of a Modular Multi-level Converter (MMC) with grid-forming control either with or without controlling the MMC internal energy. It has been demonstrated that the internal energy of the MMC in low-level control interacts with the high-level control, which is performed by a grid-forming scheme. In case of controlling the internal energy of the MMC, this interaction is mitigated. Moreover, it has been shown that the dynamic behavior of a grid-forming controlled MMC with internal energy control is identical to an equivalent 2-level Voltage Source Converter (VSC).

	Improved SoC Balancing and Active Power Sharing Control Method in Highly Resistive Line Microgrid By Yuanhao ZHU	[View] [Download]
Abstract: This paper proposes a distributed control method for AC microgrid with high resistance lines, where P-V droop control modified by average SoC obtained through the SoC average estimator to guarantee the SoC balancing and active power sharing. The results of simulations verify the effectiveness of the proposed method.

	Rapid Impedance Estimation Algorithm for Mitigation of Synchronization Instability of Paralleled Converters under Grid Faults By Mads TAUL	[View] [Download]
Abstract: Paralleled grid-connected converters operated as grid-following structures are vulnerable to transient synchronization instability during grid faults. This paper mathematically describes the instability phenomenon of paralleled converters and why it is more pronounced than for single-converter operation. Based on this model, instability can be averted by modifying each converter current reference depending on the external network impedance where asymptotic stability is proven. A rapid impedance estimation algorithm is presented, which can extract the network impedance based on the disturbance of the grid fault. This estimation is used to accurately adjust the converter current references in order to guarantee stability of all paralleled converters for any severity of the grid fault. The proposed control structure is verified in a detailed simulation study and through experimental tests, which demonstrate its potential and robustness.