EPE Association: EPE 2020 - DS3m: Industry Specific Energy Conversion and Conditionning Technologies (ECCT)

EPE 2020 - DS3m: Industry Specific Energy Conversion and Conditionning Technologies (ECCT)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 09: Industry-Specific Energy Conversion and Conditioning Technologies > EPE 2020 - DS3m: Industry Specific Energy Conversion and Conditionning Technologies (ECCT)

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   Charging High Voltage capacitors in pulsed power applications with a Capacitor Diode Voltage Multiplier of reduced size and lower ripple currents
By Tristan WEINERT [View]
[Download]

Abstract: The Cockroft-Walton multiplier is an established converter to generate high voltage, that can be used to charge capacitors for pulsed power applications.In this paper the drawbacks for this use case are shown and with the Two Phase Capacitor Diode Voltage Multiplier Type A a promising alternative solution is presented.While this topology seems to be the less obvious choice between both converters under steady state conditions, it shows its strength at repetitive capacitor charging.One of the benefits is a great reduction of the ripple currents overlayed to the desired constant DC current, by reducing reverse flowing charges and doubling the output frequency.Thus the pre-resistor for diode protection has lower losses or could be increased to improve the robustness.Filtering on the current measurement becomes simpler and disturbances are easier to avoid.The capacitor values can be greatly downscaled leading to reduced weight, size and cost.With smaller values, the power supply requirements are lowered, since the multipliers capacitance acts as an additional load to it.The reduction of energy stored inside the multiplier by a factor of 17 enhances the efficiency.

   Dead-Time influence on fast switching pulsed power converters design - A high current application for accelerator's magnets
By Alain BOUSCAYROL [View]
[Download]

Abstract: Dead-time in IGBT-based DC-DC power converters is a well-known issue that causes a limitation of the output voltage and the distortion of the output voltage and current. These distortions are more critical when the converter switching frequency increases and in applications requiring high di/dt. This is especially true for power converters used to supply pulsed electro-magnets in particle accelerators where output waveforms with high slew rates are needed. Several solutions exist to compensate the distortions caused by dead-time; however, in fast and precise applications, the compensation method should be analysed in conjunction with design choices, such as the selection of switching frequency, output filter's inductances and topology. At CERN, hybrid capacitor discharge/switch mode power converters have been developed to supply electro-magnets used for PS beam injection. For standardisation and cost reduction. Because of this design option, dead-time represents 16 \% of the switching period thus widely affecting the converter performances. This paper illustrates the effects of dead-time on various design aspects of these hybrid power converters able to produce precise 1ms long current pulses with maximal output current up to 2,5 kA. The converter control loops that have been designed using Energetic Macroscopic Representation approach can partly compensate for the dead-times effects. However, a dead-time compensation technique based on the inductor current sign measurement is nevertheless required to improve the converter performances. It is experimentally demonstrated that this classical compensation method is effective, even in interleaved switching module

   Efficiency Potential of Solid-State Pulse Modulators using SiC Devices
By Spyridon STATHIS [View]
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Abstract: In this paper, the efficiency of the CLIC solid-state pulse modulator developed for the CERN research center and the long-pulse modulator system built for the ESS facility is investigated in detail. The analysis shows the current efficiency status of the modulators and how their performance could be improved by using SiC devices.

   Electric Impulse Technology - Breaking Rock
By Matthias VOIGT [View]
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Abstract: Hard rock destruction and comminution is directly linked with a high energy demand and high costs. Conventional tools are working against the compression strength of the rock. This results in an intense wear of the used tools due to the high forces needed to destroy hard rock. In times of scarcity of resources and climate change new technologies to destroy hard rock, more efficiently have to be developed.Besides other non-mechanical technologies, like flame jet drills, high pressure fluid jet, hydrothermal spallation and drilling high power laser [1], the Electric Impulse Technology represents an alternative procedure to destroy hard rock and conglomerates with less energy and power than conventional mechanical tools. An impulse voltage generator delivers fast rising high voltage impulses to break and weaken the material structure of the rock. This effect can be used, for example, for hard rock drilling and ore comminution. Advantages are, among others, the low forces, less wear and a reduced energy demand.The paper deals with the physical basics of the Electric Impulse Technology and its fields of application. Furthermore, the behavior of the used impulse voltage generators under changed conditions in comparison with conventional impulse voltage generators will be investigated.

   Rail Potential Calculation Model for Railway Power Supply Equipped with Voltage Limiting Device
By Shota KIMURA [View]
[Download]

Abstract: In DC electric railways, voltage is generated between rail and earth, i.e., rail potential. To keep the voltage below the permissible voltage limit specified by the international standard IEC 62128, a voltage limiting device (VLD) is added to railway power supply equipment. A VLD is a switch that connects the rail and the earth. The switch is closed when the rail potential rises above a permissible voltage. This lowers the voltage of the rail potential because the rail and the earth are shorted by the closed switch. We added a VLD model to a rail potential calculation model to evaluate the VLD's affection. The VLD was modeled as variable resistance that changed the resistance value depending on the open/closed status of the switch. Once the voltage between the rail and the earth exceeds the predefined limit, the status changes to close and stays closed for a predefined time before it is reopened. The results of the case study show that rail potential is reduced to almost zero by closing multiple VLDs installed in the line. However, stray current increases because it flows through the closed VLDs. The results obtained from the actual route will be compared with the simulation results in future work.

EPE 2020 - DS3m: Industry Specific Energy Conversion and Conditionning Technologies (ECCT)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 09: Industry-Specific Energy Conversion and Conditioning Technologies > EPE 2020 - DS3m: Industry Specific Energy Conversion and Conditionning Technologies (ECCT)
	[return to parent folder]

	Charging High Voltage capacitors in pulsed power applications with a Capacitor Diode Voltage Multiplier of reduced size and lower ripple currents By Tristan WEINERT	[View] [Download]
Abstract: The Cockroft-Walton multiplier is an established converter to generate high voltage, that can be used to charge capacitors for pulsed power applications.In this paper the drawbacks for this use case are shown and with the Two Phase Capacitor Diode Voltage Multiplier Type A a promising alternative solution is presented.While this topology seems to be the less obvious choice between both converters under steady state conditions, it shows its strength at repetitive capacitor charging.One of the benefits is a great reduction of the ripple currents overlayed to the desired constant DC current, by reducing reverse flowing charges and doubling the output frequency.Thus the pre-resistor for diode protection has lower losses or could be increased to improve the robustness.Filtering on the current measurement becomes simpler and disturbances are easier to avoid.The capacitor values can be greatly downscaled leading to reduced weight, size and cost.With smaller values, the power supply requirements are lowered, since the multipliers capacitance acts as an additional load to it.The reduction of energy stored inside the multiplier by a factor of 17 enhances the efficiency.

	Dead-Time influence on fast switching pulsed power converters design - A high current application for accelerator's magnets By Alain BOUSCAYROL	[View] [Download]
Abstract: Dead-time in IGBT-based DC-DC power converters is a well-known issue that causes a limitation of the output voltage and the distortion of the output voltage and current. These distortions are more critical when the converter switching frequency increases and in applications requiring high di/dt. This is especially true for power converters used to supply pulsed electro-magnets in particle accelerators where output waveforms with high slew rates are needed. Several solutions exist to compensate the distortions caused by dead-time; however, in fast and precise applications, the compensation method should be analysed in conjunction with design choices, such as the selection of switching frequency, output filter's inductances and topology. At CERN, hybrid capacitor discharge/switch mode power converters have been developed to supply electro-magnets used for PS beam injection. For standardisation and cost reduction. Because of this design option, dead-time represents 16 \% of the switching period thus widely affecting the converter performances. This paper illustrates the effects of dead-time on various design aspects of these hybrid power converters able to produce precise 1ms long current pulses with maximal output current up to 2,5 kA. The converter control loops that have been designed using Energetic Macroscopic Representation approach can partly compensate for the dead-times effects. However, a dead-time compensation technique based on the inductor current sign measurement is nevertheless required to improve the converter performances. It is experimentally demonstrated that this classical compensation method is effective, even in interleaved switching module

	Efficiency Potential of Solid-State Pulse Modulators using SiC Devices By Spyridon STATHIS	[View] [Download]
Abstract: In this paper, the efficiency of the CLIC solid-state pulse modulator developed for the CERN research center and the long-pulse modulator system built for the ESS facility is investigated in detail. The analysis shows the current efficiency status of the modulators and how their performance could be improved by using SiC devices.

	Electric Impulse Technology - Breaking Rock By Matthias VOIGT	[View] [Download]
Abstract: Hard rock destruction and comminution is directly linked with a high energy demand and high costs. Conventional tools are working against the compression strength of the rock. This results in an intense wear of the used tools due to the high forces needed to destroy hard rock. In times of scarcity of resources and climate change new technologies to destroy hard rock, more efficiently have to be developed.Besides other non-mechanical technologies, like flame jet drills, high pressure fluid jet, hydrothermal spallation and drilling high power laser [1], the Electric Impulse Technology represents an alternative procedure to destroy hard rock and conglomerates with less energy and power than conventional mechanical tools. An impulse voltage generator delivers fast rising high voltage impulses to break and weaken the material structure of the rock. This effect can be used, for example, for hard rock drilling and ore comminution. Advantages are, among others, the low forces, less wear and a reduced energy demand.The paper deals with the physical basics of the Electric Impulse Technology and its fields of application. Furthermore, the behavior of the used impulse voltage generators under changed conditions in comparison with conventional impulse voltage generators will be investigated.

	Rail Potential Calculation Model for Railway Power Supply Equipped with Voltage Limiting Device By Shota KIMURA	[View] [Download]
Abstract: In DC electric railways, voltage is generated between rail and earth, i.e., rail potential. To keep the voltage below the permissible voltage limit specified by the international standard IEC 62128, a voltage limiting device (VLD) is added to railway power supply equipment. A VLD is a switch that connects the rail and the earth. The switch is closed when the rail potential rises above a permissible voltage. This lowers the voltage of the rail potential because the rail and the earth are shorted by the closed switch. We added a VLD model to a rail potential calculation model to evaluate the VLD's affection. The VLD was modeled as variable resistance that changed the resistance value depending on the open/closed status of the switch. Once the voltage between the rail and the earth exceeds the predefined limit, the status changes to close and stays closed for a predefined time before it is reopened. The results of the case study show that rail potential is reduced to almost zero by closing multiple VLDs installed in the line. However, stray current increases because it flows through the closed VLDs. The results obtained from the actual route will be compared with the simulation results in future work.