EPE Association: EPE 2019 - LS6d: Special Session on SCCER-Furies

EPE 2019 - LS6d: Special Session on SCCER-Furies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2019 - LS6d: Special Session on SCCER-Furies

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   Comparison of Hybrid Transformers with Uni- and Bidirectional Auxiliary Converter
By Adrian WIEMER [View]
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Abstract: Hybrid transformers (HT) are a promising concept to increase the grid flexibility. In the past, only HT with bidirectional auxiliary converter have been investigated. In this paper, HT with unidirectional auxiliary converter, which are advantageous in terms of reliability, cost and complexity, are investigated and their operational limits are derived.

   Flexible Medium Voltage DC Source Utilizing Series Connected Modular Multilevel Converters
By Milan UTVIC [View]
[Download]

Abstract: This paper presents the converter configuration acting as a medium voltage DC source. In order to obtain desired voltage across the DC terminals, two series connected modular multilevel converters are used. The use of modular multilevel converters results in high degrees of modularity, flexibility, reliability, current limiting capability during DC faults, as well as the outstanding operational performances. Each modular multilevel converter is connected to the 3.3 kV AC supply, while ensuring arbitrary voltage in the range of ± 5 kV across its DC terminals. Consequently, series connection of two power units allows for ±10kV to be synthesized across the converter's DC terminals. Moreover, there is a freedom of choice with regards to the way that two modular multilevel converters share the output DC voltage reference. Therefore, studies focusing on converter dynamics and efficiency for various voltage sharing profiles are conducted. As a result, the most optimal voltage sharing profile is generated, covering the whole operating range of the converter.

   Model-less/measurement-based computation of voltage sensitivities in unbalanced electrical distribution networks: experimental validation.
By Mokhtar BOZORG [View]
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Abstract: Thanks to its intrinsic linear properties, the application of voltage sensitivity coefficients theory for the development of fast and effective low voltage (LV) distribution grid control algorithms knows a strong interest among the scientific community. In particular, model-less methods for computation of sensitivity coefficients received lots of attention, as the accurate grid model (e.g., line parameters) is not always available in LV grids. In this paper, a model-less/measurement-based method for computation of voltage sensitivity coefficients in a real distribution grid under known operation scenario is evaluated and experimentally validated. The model-less method for computation of sensitivity coefficients has been implemented in a decentralized measurement and control device called GridEye. GridEye is a digital grid optimization tool to design, operate, monitor, analyze, and automate any power distribution grid. The tests are performed in the 'ReIne' laboratory, a new flexible structure, with nominal power up to 100kVA, able to emulate different distribution network topologies, such as radial, meshed or partly meshed network.

   The Borgna-Converter: An Alternative Solution to interleaved DC/DC Converters
By Luciano BORGNA [View]
[Download]

Abstract: In this work, a family of new and simple topologies for highly efficient, non-isolated electronic power converters is being introduced. The basic idea of this inverter family goes as follows: Two sub-converters of the well-known topologies buck, boost or buck-boost are being connected in parallel, virtually forming an interleaved converter. However, compared to standard interleaved converters, there are two major differences: First, the chopper voltages of the two sub-converters are being connected with a small coupling capacitor in parallel to a small bypass switch. Second, the method of control of the power switches is different. Due to these simple modifications, zero-current / zero-voltage switching is being achieved, effectively reducing power losses and electromagnetic interferences. With a functional prototype, the authors could show that an efficiency of more than 99\% can easily be achieved. Even though the basic function of these converters is dc-to-dc-conversion, by modulation of the output voltage, ac waveforms can be generated as well. This clears the way to inverters and synchronous rectifiers. Due to their superior performance, high flexibility and simplicity, the authors see high potential for these new converter topologies in a wide field of applications such as photovoltaic inverters, battery charging systems, traction drives and many more.

EPE 2019 - LS6d: Special Session on SCCER-Furies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2019 - LS6d: Special Session on SCCER-Furies
	[return to parent folder]

	Comparison of Hybrid Transformers with Uni- and Bidirectional Auxiliary Converter By Adrian WIEMER	[View] [Download]
Abstract: Hybrid transformers (HT) are a promising concept to increase the grid flexibility. In the past, only HT with bidirectional auxiliary converter have been investigated. In this paper, HT with unidirectional auxiliary converter, which are advantageous in terms of reliability, cost and complexity, are investigated and their operational limits are derived.

	Flexible Medium Voltage DC Source Utilizing Series Connected Modular Multilevel Converters By Milan UTVIC	[View] [Download]
Abstract: This paper presents the converter configuration acting as a medium voltage DC source. In order to obtain desired voltage across the DC terminals, two series connected modular multilevel converters are used. The use of modular multilevel converters results in high degrees of modularity, flexibility, reliability, current limiting capability during DC faults, as well as the outstanding operational performances. Each modular multilevel converter is connected to the 3.3 kV AC supply, while ensuring arbitrary voltage in the range of ± 5 kV across its DC terminals. Consequently, series connection of two power units allows for ±10kV to be synthesized across the converter's DC terminals. Moreover, there is a freedom of choice with regards to the way that two modular multilevel converters share the output DC voltage reference. Therefore, studies focusing on converter dynamics and efficiency for various voltage sharing profiles are conducted. As a result, the most optimal voltage sharing profile is generated, covering the whole operating range of the converter.

	Model-less/measurement-based computation of voltage sensitivities in unbalanced electrical distribution networks: experimental validation. By Mokhtar BOZORG	[View] [Download]
Abstract: Thanks to its intrinsic linear properties, the application of voltage sensitivity coefficients theory for the development of fast and effective low voltage (LV) distribution grid control algorithms knows a strong interest among the scientific community. In particular, model-less methods for computation of sensitivity coefficients received lots of attention, as the accurate grid model (e.g., line parameters) is not always available in LV grids. In this paper, a model-less/measurement-based method for computation of voltage sensitivity coefficients in a real distribution grid under known operation scenario is evaluated and experimentally validated. The model-less method for computation of sensitivity coefficients has been implemented in a decentralized measurement and control device called GridEye. GridEye is a digital grid optimization tool to design, operate, monitor, analyze, and automate any power distribution grid. The tests are performed in the 'ReIne' laboratory, a new flexible structure, with nominal power up to 100kVA, able to emulate different distribution network topologies, such as radial, meshed or partly meshed network.

	The Borgna-Converter: An Alternative Solution to interleaved DC/DC Converters By Luciano BORGNA	[View] [Download]
Abstract: In this work, a family of new and simple topologies for highly efficient, non-isolated electronic power converters is being introduced. The basic idea of this inverter family goes as follows: Two sub-converters of the well-known topologies buck, boost or buck-boost are being connected in parallel, virtually forming an interleaved converter. However, compared to standard interleaved converters, there are two major differences: First, the chopper voltages of the two sub-converters are being connected with a small coupling capacitor in parallel to a small bypass switch. Second, the method of control of the power switches is different. Due to these simple modifications, zero-current / zero-voltage switching is being achieved, effectively reducing power losses and electromagnetic interferences. With a functional prototype, the authors could show that an efficiency of more than 99\% can easily be achieved. Even though the basic function of these converters is dc-to-dc-conversion, by modulation of the output voltage, ac waveforms can be generated as well. This clears the way to inverters and synchronous rectifiers. Due to their superior performance, high flexibility and simplicity, the authors see high potential for these new converter topologies in a wide field of applications such as photovoltaic inverters, battery charging systems, traction drives and many more.