EPE Association: EPE 2023 - DS1e: Solid State Transformers

EPE 2023 - DS1e: Solid State Transformers
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2023 ECCE Europe - Conference > EPE 2023 - Topic 02: Power Converter Topologies and Design > EPE 2023 - DS1e: Solid State Transformers

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   A High Output Voltage Range DC-DC Converter with Solid-State Change-Over Switch
By Siegmar UNTERWEGER, Martin SCHULZ, Thomas BRÜCKNER [View]
[Download]

Abstract: The need for larger output voltage rangesof high-power electric vehicle charging systems, caused bydifferent vehicle battery voltages can lead to a decreasedefficiency over the power converter output voltage range.In this paper, a double submodule DC-DC convertertopology with a solid state change-over switch for a fasttransition between parallel and series connection of theoutput stages is proposed. The transition and the expandedfull power output voltage range is investigated troughsimulation and experimental validation.

   A Novel Asymmetrical Bidirectional DAB Converter Applied to Offshore Wind Power System
By Hanbing XIAO, Jianjun MA, Miao ZHU, Yijia CHEN [View]
[Download]

Abstract: For offshore wind power transmission system, power flows from offshore wind farms to coastal power grids unidirectionally in most working conditions. The reverse power flow situation only accounts for a little proportion. A novel asymmetrical bidirectional converter topology based on semi-DAB is proposed to meet the bidirectional differentiated power flow demand. The analysis of operation principle under both forward and reverse operation mode is completed, and the ZVS boundary is calculated. A comparison about the power transfer capacity is analyzed. Above differentiated power trans-mission capacity and soft-switching operation are verified through experiment.

   Analysis and Optimization of Current Stress for Single-Stage DAB DC/AC Converter in Micro-inverter Application
By Zhiyuan WANG, Binbin LI, Yingzong JIAO, Ruitie LI, Dianguo XU [View]
[Download]

Abstract: To optimize the current stress of a single-stage DAB DC/AC converter, the DAB topology is improved with an additional switch. The current stress is effectively reduced by actively changing the structure between half and full bridge. The operation mode, current stress analysis, and simulation results are shown in detail.

   Control Strategy for DAB using SPS for Integration of Modular Batteries in EV
By Alberto CARCAMO, Aitor VÁZQUEZ, Alberto RODRÍGUEZ, Diego G. LAMAR, Marta M. HERNANDO, Alexis A. GÓMEZ, Daniel REMON [View]
[Download]

Abstract: This paper explores a control strategy for a Dual Active Bridge (DAB) used for the integration of removable batteries on Electric Vehicles (EVs). It uses Single Phase Shift (SPS) control at different switching frequencies to increase power and extend Zero Voltage Switching (ZVS), while it works in burst mode at low power.

   Dual Active Bridge Converter With Variable Switching Frequency Modulation to Maintain ZVS
By Dingsihao LYU, Coen STRAATHOF, Thiago B.SOEIRO, Zian QIN, Pavol BAUER [View]
[Download]

Abstract: A variable switching frequency modulation for the Dual Active Bridge (DAB) converter is proposed in this paper. With this variable switching frequency modulation, the DAB converter can be operated in the ZVS-beneficial operational modes without the necessity to transition to others, thus a larger ZVS range for the DAB converter can be achieved. This modulation has potential of providing higher power efficiency and better EMI performance for the DAB converter in wide voltage range applications such as Electric Vehicle (EV) charging. A DAB converter with the variable frequency modulation method is simulated, and its effectiveness on the ZVS performance is demonstrated.

   Efficiency-Driven Parameter Selection for Dual Active Bridge Converters
By Ahmed MELIGY, Rafael COELHO MEDEIROS, Ilknur COLAK, Seddik BACHA [View]
[Download]

Abstract: This study assesses the impact of multiple system parameters on the efficiency of a dual active bridge converter considering single-phase shift, trapezoidal, and triangular modulations, along with their combinations. The findings provide insightful information on selecting the medium-frequency transformer turns ratio and the total medium-frequency link inductance to improve efficiency across the converter operation range.

   Losses Analysis of MMC in Medium Frequency Medium Voltage DAB Converter for Charging Station
By Sattar BAZYAR, Jun-Hyung JUNG, Rui LI, Hamzeh BEIRANVAND, Marco LISERRE [View]
[Download]

Abstract: Medium voltage (MV) modular multilevel converter (MMC) is an attractive candidate for multi MW fast charging station (FCS) to transfer high power with high efficiency, and a medium-frequency (MF) isolated dual active-bridge (DAB) DC/DC converter is needed to step down the voltage in this application. In this regard, MMC-based isolated DAB DC/DC converter is a good candidate to be used in FCS. In MMC-based isolated DAB DC/DC converter, Quasi-two-level (Q2L) waveform is the preferred waveform for the AC side voltage of MMC due to low dv/dt and small capacitor of submodules. The analysis on power losses of MMC in this application and with this specific AC voltage waveform is an important issue for a cellular high-efficiency design that requires more investigation. This paper provides an analysis to estimate switching and conduction losses of MMC used to produce a quasi-two-level waveform which can be used among the others also in DAB applications. Finally, the effectiveness of the losses analysis is verified by simulation results, and the experimental results are used to investigate the behavior of MMC in this application.

   Model Predictive Control for a Modular Multiport Solid-State Transformer
By Tiago OLIVEIRA, André MENDES, Luís CASEIRO [View]
[Download]

Abstract: This paper proposes a model predictive control (MPC) strategy for a modular multiport solidstatetransformer (SST). The proposed system enables the interconnection of low- and high-voltage systems including electric vehicles, renewable energy sources and DC grids.The adopted SST topology uses a modular multilevel converter (MMC) followed by input-series output-parallel dual active bridge (ISOP DAB) converters. The presented simulation results emonstrate the effectiveness of the proposed MPC-based SST controller.

   Modeling and Optimization for DAB Converter using SiC MOSFETs in Series Connection Considering Magnetizing Inductance and Voltage Ratio
By Runtian CHEN, Yibo DENG, Chushan LI, Haoze LUO, Wuhua LI, Xiangning HE [View]
[Download]

Abstract: In the field of medium voltage power transmission, the DAB converter using series-connected SiC MOSFETs (S-SiC) is a preferred solution for isolated bidirectional DC-DC conversion. However, S-SiC cannot achieve zero voltage switching-on (ZVS-on) under some operating conditions, which compromises the efficiency and reliability of the converter. This paper proposes an optimization scheme for a DAB converter with S-SiC by focusing on the magnetizing inductance and voltage ratio. The operational modes of the converter under various conditions are analyzed, and key characteristics are identified to guide the optimization design. Finally, experiments on the developed 4kV/200kW prototype demonstrate enhanced ZVS-on scope and voltage sharing in the S-SiC.

   Modeling and Power Transfer Characteristics of MMC-H based Solid State Transformer with Sine-Square Wave Modulation
By Yihao DU, Wenqi LIN, Shibo LIAN, Yihui ZHAO, Xiaojie FU, Yujia GUO, Jianyu PAN [View]
[Download]

Abstract: Compared with traditional solid-state transformers (SSTs) with multiple dual-active bridge modules, the MMC-H based SST only requires one transformer and has high control flexibility and strong fault-tolerant capability. However, existing methods mainly adopt the square-square wave modulation technique in SSTs, rendering high dv/dt voltage stress and large harmonics. This paper takes advantage of the sine-square wave technique with MMCs to enhance the voltage and current performance. An accurate power transfer model for the MMC-H SST with the sine-square wave is proposed. The transferred power and current characteristics are revealed, and the maximum power transfer point is identified. Validated by the simulation results, the proposed model has a high accuracy with an average error of less than 3\%, and transfer current harmonics is reduced by 12\% under heavy load.

   Modelling and Stability Analysis of 100kW Modular Dual Active Bridge Converter for Robotic Arm-based Charging Systems
By Ramy KOTB, Haaris RASOOL, Sajib CHAKRABORTY, Omar HEGAZY [View]
[Download]

Abstract: This paper presents the stability analysis and control design of the DC-DC stage in a 100 kW modular robotic arm-based off-board charging station. The study derives large and small signal models and defines control design requirements to ensure closed-loop stability. Finally, the performance of the proposed large and small signal models has been validated through time domain simulation results.

   Output Current Control of Three-Phase Secondary-Resonant SAB DC-DC Converter for Variation of Output Voltage
By Taisei KATO, Kohei BUDO, Takaharu TAKESHITA [View]
[Download]

Abstract: This paper presents output current control of three-phase Secondary-Resonant Single-Active-Bridge (SR-SAB) DC-DC converter by changing the frequency of the primary voltage. The proposed SR-SAB converter can reduce the transformer capacity compared with a conventional circuit. Therefore, the SR-SAB converter is suitable for high-power application. The battery charger is required to follow the output current to the output current reference in any output voltage. The effectiveness of the proposed control method is verified by experiments using a 3.5 kW laboratory prototype.

EPE 2023 - DS1e: Solid State Transformers
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2023 ECCE Europe - Conference > EPE 2023 - Topic 02: Power Converter Topologies and Design > EPE 2023 - DS1e: Solid State Transformers
	[return to parent folder]

	A High Output Voltage Range DC-DC Converter with Solid-State Change-Over Switch By Siegmar UNTERWEGER, Martin SCHULZ, Thomas BRÜCKNER	[View] [Download]
Abstract: The need for larger output voltage rangesof high-power electric vehicle charging systems, caused bydifferent vehicle battery voltages can lead to a decreasedefficiency over the power converter output voltage range.In this paper, a double submodule DC-DC convertertopology with a solid state change-over switch for a fasttransition between parallel and series connection of theoutput stages is proposed. The transition and the expandedfull power output voltage range is investigated troughsimulation and experimental validation.

	A Novel Asymmetrical Bidirectional DAB Converter Applied to Offshore Wind Power System By Hanbing XIAO, Jianjun MA, Miao ZHU, Yijia CHEN	[View] [Download]
Abstract: For offshore wind power transmission system, power flows from offshore wind farms to coastal power grids unidirectionally in most working conditions. The reverse power flow situation only accounts for a little proportion. A novel asymmetrical bidirectional converter topology based on semi-DAB is proposed to meet the bidirectional differentiated power flow demand. The analysis of operation principle under both forward and reverse operation mode is completed, and the ZVS boundary is calculated. A comparison about the power transfer capacity is analyzed. Above differentiated power trans-mission capacity and soft-switching operation are verified through experiment.

	Analysis and Optimization of Current Stress for Single-Stage DAB DC/AC Converter in Micro-inverter Application By Zhiyuan WANG, Binbin LI, Yingzong JIAO, Ruitie LI, Dianguo XU	[View] [Download]
Abstract: To optimize the current stress of a single-stage DAB DC/AC converter, the DAB topology is improved with an additional switch. The current stress is effectively reduced by actively changing the structure between half and full bridge. The operation mode, current stress analysis, and simulation results are shown in detail.

	Control Strategy for DAB using SPS for Integration of Modular Batteries in EV By Alberto CARCAMO, Aitor VÁZQUEZ, Alberto RODRÍGUEZ, Diego G. LAMAR, Marta M. HERNANDO, Alexis A. GÓMEZ, Daniel REMON	[View] [Download]
Abstract: This paper explores a control strategy for a Dual Active Bridge (DAB) used for the integration of removable batteries on Electric Vehicles (EVs). It uses Single Phase Shift (SPS) control at different switching frequencies to increase power and extend Zero Voltage Switching (ZVS), while it works in burst mode at low power.

	Dual Active Bridge Converter With Variable Switching Frequency Modulation to Maintain ZVS By Dingsihao LYU, Coen STRAATHOF, Thiago B.SOEIRO, Zian QIN, Pavol BAUER	[View] [Download]
Abstract: A variable switching frequency modulation for the Dual Active Bridge (DAB) converter is proposed in this paper. With this variable switching frequency modulation, the DAB converter can be operated in the ZVS-beneficial operational modes without the necessity to transition to others, thus a larger ZVS range for the DAB converter can be achieved. This modulation has potential of providing higher power efficiency and better EMI performance for the DAB converter in wide voltage range applications such as Electric Vehicle (EV) charging. A DAB converter with the variable frequency modulation method is simulated, and its effectiveness on the ZVS performance is demonstrated.

	Efficiency-Driven Parameter Selection for Dual Active Bridge Converters By Ahmed MELIGY, Rafael COELHO MEDEIROS, Ilknur COLAK, Seddik BACHA	[View] [Download]
Abstract: This study assesses the impact of multiple system parameters on the efficiency of a dual active bridge converter considering single-phase shift, trapezoidal, and triangular modulations, along with their combinations. The findings provide insightful information on selecting the medium-frequency transformer turns ratio and the total medium-frequency link inductance to improve efficiency across the converter operation range.

	Losses Analysis of MMC in Medium Frequency Medium Voltage DAB Converter for Charging Station By Sattar BAZYAR, Jun-Hyung JUNG, Rui LI, Hamzeh BEIRANVAND, Marco LISERRE	[View] [Download]
Abstract: Medium voltage (MV) modular multilevel converter (MMC) is an attractive candidate for multi MW fast charging station (FCS) to transfer high power with high efficiency, and a medium-frequency (MF) isolated dual active-bridge (DAB) DC/DC converter is needed to step down the voltage in this application. In this regard, MMC-based isolated DAB DC/DC converter is a good candidate to be used in FCS. In MMC-based isolated DAB DC/DC converter, Quasi-two-level (Q2L) waveform is the preferred waveform for the AC side voltage of MMC due to low dv/dt and small capacitor of submodules. The analysis on power losses of MMC in this application and with this specific AC voltage waveform is an important issue for a cellular high-efficiency design that requires more investigation. This paper provides an analysis to estimate switching and conduction losses of MMC used to produce a quasi-two-level waveform which can be used among the others also in DAB applications. Finally, the effectiveness of the losses analysis is verified by simulation results, and the experimental results are used to investigate the behavior of MMC in this application.

	Model Predictive Control for a Modular Multiport Solid-State Transformer By Tiago OLIVEIRA, André MENDES, Luís CASEIRO	[View] [Download]
Abstract: This paper proposes a model predictive control (MPC) strategy for a modular multiport solidstatetransformer (SST). The proposed system enables the interconnection of low- and high-voltage systems including electric vehicles, renewable energy sources and DC grids.The adopted SST topology uses a modular multilevel converter (MMC) followed by input-series output-parallel dual active bridge (ISOP DAB) converters. The presented simulation results emonstrate the effectiveness of the proposed MPC-based SST controller.

	Modeling and Optimization for DAB Converter using SiC MOSFETs in Series Connection Considering Magnetizing Inductance and Voltage Ratio By Runtian CHEN, Yibo DENG, Chushan LI, Haoze LUO, Wuhua LI, Xiangning HE	[View] [Download]
Abstract: In the field of medium voltage power transmission, the DAB converter using series-connected SiC MOSFETs (S-SiC) is a preferred solution for isolated bidirectional DC-DC conversion. However, S-SiC cannot achieve zero voltage switching-on (ZVS-on) under some operating conditions, which compromises the efficiency and reliability of the converter. This paper proposes an optimization scheme for a DAB converter with S-SiC by focusing on the magnetizing inductance and voltage ratio. The operational modes of the converter under various conditions are analyzed, and key characteristics are identified to guide the optimization design. Finally, experiments on the developed 4kV/200kW prototype demonstrate enhanced ZVS-on scope and voltage sharing in the S-SiC.

	Modeling and Power Transfer Characteristics of MMC-H based Solid State Transformer with Sine-Square Wave Modulation By Yihao DU, Wenqi LIN, Shibo LIAN, Yihui ZHAO, Xiaojie FU, Yujia GUO, Jianyu PAN	[View] [Download]
Abstract: Compared with traditional solid-state transformers (SSTs) with multiple dual-active bridge modules, the MMC-H based SST only requires one transformer and has high control flexibility and strong fault-tolerant capability. However, existing methods mainly adopt the square-square wave modulation technique in SSTs, rendering high dv/dt voltage stress and large harmonics. This paper takes advantage of the sine-square wave technique with MMCs to enhance the voltage and current performance. An accurate power transfer model for the MMC-H SST with the sine-square wave is proposed. The transferred power and current characteristics are revealed, and the maximum power transfer point is identified. Validated by the simulation results, the proposed model has a high accuracy with an average error of less than 3\%, and transfer current harmonics is reduced by 12\% under heavy load.

	Modelling and Stability Analysis of 100kW Modular Dual Active Bridge Converter for Robotic Arm-based Charging Systems By Ramy KOTB, Haaris RASOOL, Sajib CHAKRABORTY, Omar HEGAZY	[View] [Download]
Abstract: This paper presents the stability analysis and control design of the DC-DC stage in a 100 kW modular robotic arm-based off-board charging station. The study derives large and small signal models and defines control design requirements to ensure closed-loop stability. Finally, the performance of the proposed large and small signal models has been validated through time domain simulation results.

	Output Current Control of Three-Phase Secondary-Resonant SAB DC-DC Converter for Variation of Output Voltage By Taisei KATO, Kohei BUDO, Takaharu TAKESHITA	[View] [Download]
Abstract: This paper presents output current control of three-phase Secondary-Resonant Single-Active-Bridge (SR-SAB) DC-DC converter by changing the frequency of the primary voltage. The proposed SR-SAB converter can reduce the transformer capacity compared with a conventional circuit. Therefore, the SR-SAB converter is suitable for high-power application. The battery charger is required to follow the output current to the output current reference in any output voltage. The effectiveness of the proposed control method is verified by experiments using a 3.5 kW laboratory prototype.