EPE Association: EPE 2019 - DS2d: Advanced Power Converter Topologies II

EPE 2019 - DS2d: Advanced Power Converter Topologies II
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 02: Power Converter Topologies and Design > EPE 2019 - DS2d: Advanced Power Converter Topologies II

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   A Fault Tolerant AC/DC Converter for Electrical Gen-Set Applications
By Salvatore FOTI [View]
[Download]

Abstract: A fault tolerant AC/DC Converter for Electrical Gen-Set applications is presented based on a multilevel, openend winding, topology managed by a suitable control strategy. More precisely, the considered converter topology provides the mean to independently control the currents of two phases when the third one is open without the need to reconfigure the circuit through auxiliary switches. The electrical generator is thus forced to operate in a two-phase mode, while holding the output DC voltage at the value generated by the system in health conditions. According to the proposed approach, this is achieved only by modifying the reference frame transformation accomplished to control the current vector. The effectiveness of the proposed solution is evaluated by simulations performed on a 2kW PMSG system.

   DC-AC MULTILEVEL T-TYPE ISOLATED THREE-PHASE INDIRECT MATRIX INVERTER
By Ailton DUTRA [View]
[Download]

Abstract: In this work it is proposed a multilevel T-type configuration for a high-frequency pulsating DC-link inverter for three-phase applications. The configuration consists of two DC/DC-pulsating converters cascaded with a DC-link capacitor-less three-phase three-level T-type inverter. Due to the absence of DC-link electrolytic capacitors, the proposed inverter guarantees a long lifetime and high power density. The DC-DC-pulsating converters aim to generate the high-frequency pulsating DC-link waveform profiles which have to be synchronized with the three-phase inverter PWM. Comparing to the conventional PWM, the proposed technique presents reduced switching losses due to the fact only one leg commutes during a switching period while the other two legs keep clamped in high or low impedance. Details of control strategy and modulation are presented, such as experimental results to validate the theoretical approach.

   DC-link Voltage Balancing Converter with Resonant Switched-Capacitor Circuit for Four-Level and Six-Level NPC Inverter
By Robert STALA [View]
[Download]

Abstract: This paper presents research results on a novel concept of switched-capacitor (SC) voltage balancersuitable for DC-link voltage balance in 4-level and 6-level NPC (Neutral Point Clamped) inverters.The balancer enables the transfer the energy between any capacitors in the DC-link with variousdynamics in a controlled way, maintaining high efficiency thanks to Zero Current Switching (ZCS)and minimizing application cost using low volume LC components, bootstrap type gate circuitry fortransistor switches. This paper presents concepts of operation, switching strategies, simulation results,design issues and finally results of research conducted on experimental setup for various testscenarios.

   Experimental Validation of Five-Level Cascaded Flying-Capacitor Converter for Machine-side Operation
By Yves HEIN [View]
[Download]

Abstract: This paper presents experimental results of a test bench, which consists of a five-level CascadedFlying-Capacitor converter in combination with a 2.2kWinduction machine. First, a comparisonwith a conventional Active-Neutral-Point-Clamped converter is made. Special properties of theproposed five-level converter are shown. Afterwards, the first measurement results are presented.

   Fault Tolerance in Multiple-Active Bridge Converters Applied in Smart Transformers
By Victor FERREIRA [View]
[Download]

Abstract: Redundancy strategies have been used to ensure continuity of service facing catastrophic failure events in power converters. However, additional parts are needed, resulting in increased cost, size and weight. The increasing demand of high power density and low-cost systems, motivates more reliable converters with few additional parts. This work, address the scientific question on which modular dc-dc converter shall be selected to achieve a required residual power with minimum redundancy level. The Smart Transformer is used as a case study for a probability analysis of power derating, under successive failure events.It is shown that the Multiple-Active Bridge based converters have higher probability for more residualpower in multiple failure scenarios, and ensure high reliability in long operating time with minimumredundancy level.

   Influence of the Filter Design on Wide-Bandgap Voltage Source Inverters with Sine Wave Filter for Electrical Drives
By Matthias ZEHELEIN [View]
[Download]

Abstract: State-of-the-art electric drives are mainly equipped with two level three phase voltage source inverters offering an compact setup with good efficiency but electromagnetic interference is an issue especially in sensitive environments. Also bearing currents, excited by common-mode noise, can influence the reliability of the connected machine.To reduce these bearing currents and the inverter's electromagnetic compatibility an output filter can be used. Especially with wide band-gap semiconductors the reduced switching losses offer output filters with low volume. Furthermore, this filter offers several degrees of freedom to optimize the losses of the whole inverter system. Possible filter designs are investigated and compared with each other. A design methodology to find loss optimized filter configurations is presented. By modeling the whole inverter and filter system the losses of the system are calculated for every filter configuration iteratively at a desired operating point. These loss models consider soft switching behavior as well as high frequency losses of the passives to take also configurations with high filter choke current ripple into account.

   Multilevel Inverters: A survey of limitations and recommended problem-solving techniques
By Theodoros MOUSELINOS [View]
[Download]

Abstract: In this paper, voltage and current imbalance problems that arise during steady-state operation of multilevel inverters are investigated. Especially, Cascaded H-Bridge, Diode Clamped and Flying Capacitor multilevel inverters are studied. To overcome these limitations, some problem-handling techniques are proposed to consolidate the use of these topologies in modern day applications. To further validate some proposed problem-solving techniques through experimental probing, a laboratory prototype of a five-level CHBMLI is implemented.

   Parallel-Serial-Rectifier for Power-to-Hydrogen Applications
By Steffen BINTZ [View]
[Download]

Abstract: This paper presents a new rectifier topology for energy storage utilizing electrolysis in low voltagepower grids without the typically needed isolation transformer. The proposed concept uses a voltageaddition to pre-shape the input voltage of the rectifier to obtain a smoothed output voltage. At the gridconnection, a current addition is designated to provide a good power factor. The power electronicconcept as well as its control strategy have been developed and adapted according to power qualityand efficiency. The rectifier concept is proven by simulation and measurements on a kilowatt-scaledemonstrator.

   Performance Comparison between Sequential Command SPWM and MLI-NPC in Multi-MW drives for WECSs
By Khaled ELSHAWARBY [View]
[Download]

Abstract: The paper presents a comparison between two energy conversion methods for a multi-modular axial fluxmachine used for wind energy conversion systems, namely: Sequential Command for series connectedtwo-level converters and a Multilevel NPC converter. The Sequential Command is the shift of the carriersignals for the neighbouring two-level converters connected in series in order to minimize harmonicdistortion. A phase disposition PWM is used for Multilevel NPC since it offers much lower harmoniccontent. The comparison takes into account both harmonic content of current and torque waveforms andlosses in the converter.

   Predictive-based Modulation Schemes for the Hybrid Modular Multilevel Converter
By Felipe DONOSO [View]
[Download]

Abstract: In this paper, two predictive modulation schemes are derived for a hybrid modular multilevel converter.The modulation scheme considers the electric model of both full and half bridge cells to predict thecapacitor voltages in the next sampling period. The performance of both modulators is assessed through simulations and experimental results for different modulation indices.

   SHEPWM based New Hybrid Multilevel Inverter Topology with Reduced Switch Count
By Marif SIDDIQUE [View]
[Download]

Abstract: In this paper, a new single-phase hybrid multilevel inverter topology is proposed with reduced switch count. The basic unit of the proposed topology is capable of generating 13 levels at the output. A higher number of levels can be generated by extending the basic unit. Two different extensions of thebasic unit have been proposed in the paper. The topology consists of a level generation unit (LGU) and the polarity changing unit (PCU). The level generation unit of the proposed topology is based on the series connection of multiple switched dc voltage sources with half and full bridge configurations. Selective Harmonic Elimination PWM (SHEPWM) based switching control technique has been employed for an improved harmonic spectrum. Performance and effectiveness of the proposed topology with the employed SHEPWM control have been substantiated by simulation results and verified by experimental results obtained from a laboratory prototype.

   Switched-trans-Z-source Inverter with high boost inversion ability
By Shuai DONG [View]
[Download]

Abstract: This paper develops a novel converter with three-winding transformers, called switched-trans-Z-source inverter (ST-ZSI). Compared with the conventional Z-source inverter (ZSI), the proposed cir-cuit provides a higher boost voltage capability. The operating principles and theoretical findings have been verified by experiments.

EPE 2019 - DS2d: Advanced Power Converter Topologies II
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 02: Power Converter Topologies and Design > EPE 2019 - DS2d: Advanced Power Converter Topologies II
	[return to parent folder]

	A Fault Tolerant AC/DC Converter for Electrical Gen-Set Applications By Salvatore FOTI	[View] [Download]
Abstract: A fault tolerant AC/DC Converter for Electrical Gen-Set applications is presented based on a multilevel, openend winding, topology managed by a suitable control strategy. More precisely, the considered converter topology provides the mean to independently control the currents of two phases when the third one is open without the need to reconfigure the circuit through auxiliary switches. The electrical generator is thus forced to operate in a two-phase mode, while holding the output DC voltage at the value generated by the system in health conditions. According to the proposed approach, this is achieved only by modifying the reference frame transformation accomplished to control the current vector. The effectiveness of the proposed solution is evaluated by simulations performed on a 2kW PMSG system.

	DC-AC MULTILEVEL T-TYPE ISOLATED THREE-PHASE INDIRECT MATRIX INVERTER By Ailton DUTRA	[View] [Download]
Abstract: In this work it is proposed a multilevel T-type configuration for a high-frequency pulsating DC-link inverter for three-phase applications. The configuration consists of two DC/DC-pulsating converters cascaded with a DC-link capacitor-less three-phase three-level T-type inverter. Due to the absence of DC-link electrolytic capacitors, the proposed inverter guarantees a long lifetime and high power density. The DC-DC-pulsating converters aim to generate the high-frequency pulsating DC-link waveform profiles which have to be synchronized with the three-phase inverter PWM. Comparing to the conventional PWM, the proposed technique presents reduced switching losses due to the fact only one leg commutes during a switching period while the other two legs keep clamped in high or low impedance. Details of control strategy and modulation are presented, such as experimental results to validate the theoretical approach.

	DC-link Voltage Balancing Converter with Resonant Switched-Capacitor Circuit for Four-Level and Six-Level NPC Inverter By Robert STALA	[View] [Download]
Abstract: This paper presents research results on a novel concept of switched-capacitor (SC) voltage balancersuitable for DC-link voltage balance in 4-level and 6-level NPC (Neutral Point Clamped) inverters.The balancer enables the transfer the energy between any capacitors in the DC-link with variousdynamics in a controlled way, maintaining high efficiency thanks to Zero Current Switching (ZCS)and minimizing application cost using low volume LC components, bootstrap type gate circuitry fortransistor switches. This paper presents concepts of operation, switching strategies, simulation results,design issues and finally results of research conducted on experimental setup for various testscenarios.

	Experimental Validation of Five-Level Cascaded Flying-Capacitor Converter for Machine-side Operation By Yves HEIN	[View] [Download]
Abstract: This paper presents experimental results of a test bench, which consists of a five-level CascadedFlying-Capacitor converter in combination with a 2.2kWinduction machine. First, a comparisonwith a conventional Active-Neutral-Point-Clamped converter is made. Special properties of theproposed five-level converter are shown. Afterwards, the first measurement results are presented.

	Fault Tolerance in Multiple-Active Bridge Converters Applied in Smart Transformers By Victor FERREIRA	[View] [Download]
Abstract: Redundancy strategies have been used to ensure continuity of service facing catastrophic failure events in power converters. However, additional parts are needed, resulting in increased cost, size and weight. The increasing demand of high power density and low-cost systems, motivates more reliable converters with few additional parts. This work, address the scientific question on which modular dc-dc converter shall be selected to achieve a required residual power with minimum redundancy level. The Smart Transformer is used as a case study for a probability analysis of power derating, under successive failure events.It is shown that the Multiple-Active Bridge based converters have higher probability for more residualpower in multiple failure scenarios, and ensure high reliability in long operating time with minimumredundancy level.

	Influence of the Filter Design on Wide-Bandgap Voltage Source Inverters with Sine Wave Filter for Electrical Drives By Matthias ZEHELEIN	[View] [Download]
Abstract: State-of-the-art electric drives are mainly equipped with two level three phase voltage source inverters offering an compact setup with good efficiency but electromagnetic interference is an issue especially in sensitive environments. Also bearing currents, excited by common-mode noise, can influence the reliability of the connected machine.To reduce these bearing currents and the inverter's electromagnetic compatibility an output filter can be used. Especially with wide band-gap semiconductors the reduced switching losses offer output filters with low volume. Furthermore, this filter offers several degrees of freedom to optimize the losses of the whole inverter system. Possible filter designs are investigated and compared with each other. A design methodology to find loss optimized filter configurations is presented. By modeling the whole inverter and filter system the losses of the system are calculated for every filter configuration iteratively at a desired operating point. These loss models consider soft switching behavior as well as high frequency losses of the passives to take also configurations with high filter choke current ripple into account.

	Multilevel Inverters: A survey of limitations and recommended problem-solving techniques By Theodoros MOUSELINOS	[View] [Download]
Abstract: In this paper, voltage and current imbalance problems that arise during steady-state operation of multilevel inverters are investigated. Especially, Cascaded H-Bridge, Diode Clamped and Flying Capacitor multilevel inverters are studied. To overcome these limitations, some problem-handling techniques are proposed to consolidate the use of these topologies in modern day applications. To further validate some proposed problem-solving techniques through experimental probing, a laboratory prototype of a five-level CHBMLI is implemented.

	Parallel-Serial-Rectifier for Power-to-Hydrogen Applications By Steffen BINTZ	[View] [Download]
Abstract: This paper presents a new rectifier topology for energy storage utilizing electrolysis in low voltagepower grids without the typically needed isolation transformer. The proposed concept uses a voltageaddition to pre-shape the input voltage of the rectifier to obtain a smoothed output voltage. At the gridconnection, a current addition is designated to provide a good power factor. The power electronicconcept as well as its control strategy have been developed and adapted according to power qualityand efficiency. The rectifier concept is proven by simulation and measurements on a kilowatt-scaledemonstrator.

	Performance Comparison between Sequential Command SPWM and MLI-NPC in Multi-MW drives for WECSs By Khaled ELSHAWARBY	[View] [Download]
Abstract: The paper presents a comparison between two energy conversion methods for a multi-modular axial fluxmachine used for wind energy conversion systems, namely: Sequential Command for series connectedtwo-level converters and a Multilevel NPC converter. The Sequential Command is the shift of the carriersignals for the neighbouring two-level converters connected in series in order to minimize harmonicdistortion. A phase disposition PWM is used for Multilevel NPC since it offers much lower harmoniccontent. The comparison takes into account both harmonic content of current and torque waveforms andlosses in the converter.

	Predictive-based Modulation Schemes for the Hybrid Modular Multilevel Converter By Felipe DONOSO	[View] [Download]
Abstract: In this paper, two predictive modulation schemes are derived for a hybrid modular multilevel converter.The modulation scheme considers the electric model of both full and half bridge cells to predict thecapacitor voltages in the next sampling period. The performance of both modulators is assessed through simulations and experimental results for different modulation indices.

	SHEPWM based New Hybrid Multilevel Inverter Topology with Reduced Switch Count By Marif SIDDIQUE	[View] [Download]
Abstract: In this paper, a new single-phase hybrid multilevel inverter topology is proposed with reduced switch count. The basic unit of the proposed topology is capable of generating 13 levels at the output. A higher number of levels can be generated by extending the basic unit. Two different extensions of thebasic unit have been proposed in the paper. The topology consists of a level generation unit (LGU) and the polarity changing unit (PCU). The level generation unit of the proposed topology is based on the series connection of multiple switched dc voltage sources with half and full bridge configurations. Selective Harmonic Elimination PWM (SHEPWM) based switching control technique has been employed for an improved harmonic spectrum. Performance and effectiveness of the proposed topology with the employed SHEPWM control have been substantiated by simulation results and verified by experimental results obtained from a laboratory prototype.

	Switched-trans-Z-source Inverter with high boost inversion ability By Shuai DONG	[View] [Download]
Abstract: This paper develops a novel converter with three-winding transformers, called switched-trans-Z-source inverter (ST-ZSI). Compared with the conventional Z-source inverter (ZSI), the proposed cir-cuit provides a higher boost voltage capability. The operating principles and theoretical findings have been verified by experiments.