EPE Association: EPE 2011 - LS1e: Topic 05: High Power Multi-Level Converters and Voltage Regulator Modules

EPE 2011 - LS1e: Topic 05: High Power Multi-Level Converters and Voltage Regulator Modules
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 05: Hard Switching Inverters and Control > EPE 2011 - LS1e: Topic 05: High Power Multi-Level Converters and Voltage Regulator Modules

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   Comparison of load inverter topologies in a bipolar LVDC distribution
By Jenni REKOLA, Heikki TUUSA [View]
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Abstract: Low voltage direct current (LVDC) distribution is a new low voltage distribution concept. In this study, potential line and load converter topologies for a bipolar LVDC 1500 V distribution system are compared. It is possible to supply the LVDC network by one or two line converters and the line and load converters can be connected to 750 V DC or 1500 V DC. 12-pulse half-controlled thyristor bridges, two- and three-level PWM converters and Vienna-rectifiers can be used as the line converters and two- and three-level single-phase half and full PWM bridges and three-phase converters can be used as the load converters in the LVDC distribution. The bases for the converter comparison are size of required LCL- and LC-filters, voltage and current stresses of the power semiconductor switches and the capability to operate with bidirectional power flow in the case of line converters. Furthermore, the bases of the load converter comparison are the capability to operate with reduced DC voltage and the capability to feed a half-wave rectifying load. According to the simulation results, the most suitable line converter is the three-level converter if a bidirectional power flow is needed and the Vienna-rectifier if a unidirectional power flow is adequate. The balancing circuit needs to be added to the LVDC network to maintain the voltage balance of the DC capacitors if the LVDC network is supplied by one line converter and the DC link is loaded asymmetrically. According to the simulation results, the most suitable single-phase load converter topologies connected to 750 V DC are the two- and three-level full bridges and the most suitable load converter topologies connected to 1500 V DC are the three-level topologies.

   CONTROL OF FIVE-LEVEL SINGLE-PHASE CURRENT-SOURCE INVERTERS OPERATING AT HIGH AND LOW LOAD CONDITIONS
By Bakri HASSAN, Volker PICKERT, Bashar ZAHAWI [View]
[Download]

Abstract: This paper describes an enhanced control technique to improve the output current quality of a multilevel current-source inverter operating at both high- and light-load conditions. The new technique, named here as RS-PWM, combines the simple control of redundant-switching methods with more flexible PWM methods and has been shown in this study to be superior to both. The results have been validated by laboratory experiments using a 250 VA test circuit.

   Direct Modular Multi-Level Converter for Gearless Low-Speed Drives
By Arthur KORN, Manfred WINKELNKEMPER, Peter STEIMER, Johann KOLAR [View]
[Download]

Abstract: The suitability of the direct modular multi-level converter for high power, low speed, gear- andtransformerless drives is investigated. Control methods which optimize the capacitor voltage rippleare presented, analyzed and verified in simulation.

EPE 2011 - LS1e: Topic 05: High Power Multi-Level Converters and Voltage Regulator Modules
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2011 ECCE Europe - Conference > EPE 2011 - Topic 05: Hard Switching Inverters and Control > EPE 2011 - LS1e: Topic 05: High Power Multi-Level Converters and Voltage Regulator Modules
	[return to parent folder]

	Comparison of load inverter topologies in a bipolar LVDC distribution By Jenni REKOLA, Heikki TUUSA	[View] [Download]
Abstract: Low voltage direct current (LVDC) distribution is a new low voltage distribution concept. In this study, potential line and load converter topologies for a bipolar LVDC 1500 V distribution system are compared. It is possible to supply the LVDC network by one or two line converters and the line and load converters can be connected to 750 V DC or 1500 V DC. 12-pulse half-controlled thyristor bridges, two- and three-level PWM converters and Vienna-rectifiers can be used as the line converters and two- and three-level single-phase half and full PWM bridges and three-phase converters can be used as the load converters in the LVDC distribution. The bases for the converter comparison are size of required LCL- and LC-filters, voltage and current stresses of the power semiconductor switches and the capability to operate with bidirectional power flow in the case of line converters. Furthermore, the bases of the load converter comparison are the capability to operate with reduced DC voltage and the capability to feed a half-wave rectifying load. According to the simulation results, the most suitable line converter is the three-level converter if a bidirectional power flow is needed and the Vienna-rectifier if a unidirectional power flow is adequate. The balancing circuit needs to be added to the LVDC network to maintain the voltage balance of the DC capacitors if the LVDC network is supplied by one line converter and the DC link is loaded asymmetrically. According to the simulation results, the most suitable single-phase load converter topologies connected to 750 V DC are the two- and three-level full bridges and the most suitable load converter topologies connected to 1500 V DC are the three-level topologies.

	CONTROL OF FIVE-LEVEL SINGLE-PHASE CURRENT-SOURCE INVERTERS OPERATING AT HIGH AND LOW LOAD CONDITIONS By Bakri HASSAN, Volker PICKERT, Bashar ZAHAWI	[View] [Download]
Abstract: This paper describes an enhanced control technique to improve the output current quality of a multilevel current-source inverter operating at both high- and light-load conditions. The new technique, named here as RS-PWM, combines the simple control of redundant-switching methods with more flexible PWM methods and has been shown in this study to be superior to both. The results have been validated by laboratory experiments using a 250 VA test circuit.

	Direct Modular Multi-Level Converter for Gearless Low-Speed Drives By Arthur KORN, Manfred WINKELNKEMPER, Peter STEIMER, Johann KOLAR	[View] [Download]
Abstract: The suitability of the direct modular multi-level converter for high power, low speed, gear- andtransformerless drives is investigated. Control methods which optimize the capacitor voltage rippleare presented, analyzed and verified in simulation.