EPE Association: EPE 2025 - DS2j: AC/DC and DC/AC Converter Topologies

EPE 2025 - DS2j: AC/DC and DC/AC Converter Topologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2025 - Conference > EPE 2025 - Topic 09: Power Converter Topologies > EPE 2025 - DS2j: AC/DC and DC/AC Converter Topologies

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   A Cost-Effective Three Level Shared Leg Flying Capacitor Converter for Switched Reluctance Motors
By Ali YOUSEFI DARANI, Nasir ALI, Mehdi NARIMANI [View]
[Download]

Abstract: This paper presents a novel, cost-effective multilevel inverter for switched reluctance motor (SRM) drives. The proposed inverter has a three-level topology with shared-leg flying-capacitor (SLFC) structure. This topology utilizes two shared legs for adjacent phases during the magnetization, freewheeling, and demagnetization of the SRM. This innovative approach reduces the drive's size and cost by reducing the number of power switches, diodes, gate drivers, current and voltage sensors while achieving the same performance as the conventional three-level flying capacitor topology. In comparison to the conventional asymmetric half bridge converter, it improves the performance in terms of current ripple and reduces the voltage stress of some of semiconductors. The feasibility of the proposed three-level SLFC topology is verified through simulation studies based on a three-phase 12/16 SRM drive system.

   A novel Hybrid Inverter Drive for AC motors capable of bypassing the voltage source inverter when operating at grid frequency
By Daniel LENDI, Reiko RAUTE, Cedric CARUANA [View]
[Download]

Abstract: Variable speed drives (VSDs) offer reduced power consumption for applications which allowoperation at reduced motor speed. However, when continuous operation at the grid frequencyis required, the VSD may become redundant, as it introduces conversion losses and electromagneticinterference (EMI), in contrast to grid-connected operation. It is hereby proposed to bypass theVSD for continuous operation at the grid frequency. This paper introduces a VSD, based ona two-level voltage source inverter (VSI), capable of transferring a motor load between grid- andinverter-connected operations, depending on the required motor speed. This paper presents athorough analysis of the conditions under which the motor load may be transitioned from eitheroperating mode. Thyristors are used as bypass devices. Simulation results for open and semi-closed transitions are presented, examining their impacts on the motor torque and stator currents.

   A performance comparison between different PWM techniques for the Hybrid Inverter Drive
By Daniel LENDI, Reiko RAUTE, Cedric CARUANA [View]
[Download]

Abstract: Variable Speed Drives (VSDs) allow energy savings for loads where operation below the gridfrequency may be required. However, when operating the motor load at the grid frequency,they introduce, compared to grid-connected operation, energy losses and ElectromagneticInterference (EMI). The Hybrid Inverter Drive (HID) offers maximum efficiency at either modeof operation. With the HID the motor load is operated in inverter-driven mode for motorfrequencies below grid frequency and operated in direct grid-connected mode for operation at gridfrequency. This eliminates inverter losses and EMI at the grid frequency. In previous work [5],the HID and its semi-closed transitions were introduced. A performance comparison of theHID operation using pure Sinusoidal PWM (SPWM), Space Vector PWM (SVPWM) and theinjection of the DC-link mid-point voltage into the SPWM reference signals during semi-closedtransitions is presented in this paper. The HID is modelled in MATLAB Simulink.

   Data-Driven RUL Estimation for DC-Link Capacitor in Ultra-Fast EV Charging Systems
By Suwaiba MATEEN, Ahteshamul HAQUE, Mohammed Ali KHAN, Thomas EBEL, Shabana MEHFUZ [View]
[Download]

Abstract: The reliability of ultra-fast electric vehicle charging systems heavily depends on the performance of critical components, notably the DC-link capacitor. This paper introduces a data driven approach for estimating the remaining useful life of DC-link capacitors in such systems. A virtual model of the system, developed as a digital twin, integrates real-time operational data with machine learning algorithms trained on historical degradation patterns. Key health indicators, such as a 30\% reduction in capacitance (from 20,000 µF) and a 100\% increase in Equivalent Series Resistance (from 0.4 mO), define the failure thresholds. Simulation-based validation demonstrates the effectiveness of the proposed methodology in accurately predicting capacitor degradation trends. This approach enhances the reliability of high-power EV charging systems and highlights the role of digital twins in predictive maintenance.

   Efficiency and Cost Comparison of GaN/Siand SiC/Si Hybrid ANPC Three-phase Inverter
By Manex GONDAT, Ander ÁVILA, Asier GARCIA, Alejandro RUJAS [View]
[Download]

Abstract: This paper evaluates the benefits of a hybrid Active Neutral Point Clamped (ANPC) topology that combines Wide Band Gap (WBG) materials, Gallium Nitride (GaN) or Silicon Carbide (SiC), with Silicon (Si) technologies. The proposed topology enables the integration of GaN semiconductors, typically rated up to 650 V, into 800 V bus applications\_ an input voltage that the automotive market tends to reach. Using hybridization of semiconductor technologies, the system achieves substantial cost reduction without compromising efficiency. The concept is experimentally validated using a 15 kW three-phase prototype.

   Methodology for pre-sizing an MMC by optimization for an aeronautical application
By Stéphane NGO BUI HUNG, Cyrille GAUTIER, Lucas PNIAK, Loïc QUÉVAL, Bertrand REVOL, Éric LABOURÉ [View]
[Download]

Abstract: This article presents the pre-sizing of L\_arm, C\_eq components of a 150 kW MMC converter in steady state used as an active rectifier, associated with a variable frequency PMSM generator, and designed to generate an 800 VDC aircraft electrical network. It details the simulation and modelling used and the optimisation process implemented.

   Model Predictive Current Control(MPCC) Using Multi Virtual Voltage Vectors for a Two-Level Inverter in Electric Propulsion Ships
By Chan ROH, Hyeon-Gyo CHAE, Eui-Cheol SHIN [View]
[Download]

Abstract: In response to environmental concerns, electric propulsion ships are emerging as a key technology in the maritime industry. The inverter, which controls the propulsion motor, is a critical component in electric propulsion ships. The 2-level voltage source inverter is widely implemented in small and medium-sized ships, but its output performance remains constrained due to limited number of voltage vectors. The proposed approach enables 2-level voltage source inverters to achieve multilevel inverter-comparable performance by adding virtual voltage vectors. While it incurs increased computational burden, the proposed method achieves performance enhancement without computational burden through the application of pre-voltage selection. Experiments have shown improvements in output current THD and current error. The results demonstrate potential advantages for electric propulsion systems.

   Modular multilevel converter based on unipolar-current full-bridge submodules for medium voltage variable speed drive applications
By Duro BASIC, Hatim ABBI, Martin GESKE [View]
[Download]

Abstract: With the continuous development of Modular Multilevel Converters (MMC), the introduction of new Sub-Modules (SMs) and their operational characteristics has become favourable for optimizing the performance of many applications such as Variable Speed Drives (VSD), where the conventional ac/dc/ac MMC converters based on Half Bridge (HB) face challenges in low-frequency operation. This paper focuses on the main features of the Unipolar Current (UC) Full-Bridge (FB) SM (UC FB-SM) and benefits of its integration into the MMCs for VSD applications. Basic operation methods of the HB and UC FB based MMCs are analysed and compared, and the duality between their operational modes is highlighted. Main advantages of utilization of the UC FB MMCs in VSD applications are identified and illustrated in the simulation results presented.

   Multi-line input network for class EF inverter with enhanced design flexibility
By Baptiste DAIRE, Christian MARTIN, Fabien SIXDENIER, Charles JOUBERT, Loris PACE [View]
[Download]

Abstract: This paper addresses a new input network for the class EF inverter, which utilizes multiple transmission lines instead of the commonly used quarter-wave line. Experimental demonstrations at 15 MHz with 40 W output power are conducted, showcasing that enhanced performance can be achieved with the proposed input network.

   Operation modes and design consideration for MMC with unipolar current full-bridge submodules
By Martin GESKE, Hatim ABBI, Duro BASIC [View]
[Download]

Abstract: The unipolar current full-bridge submodule (SM) for modular multilevel converters (MMC) operates with unipolar current and bipolar voltage. Two basic operating modes for unipolar arm currents are presented, described, and analyzed. The differences between the two idealized operating modes are further discussed regarding the system design of an MMC. The design factors for current and voltage in the DC-link differ, which leads, for example, to different numbers of SMs and power losses. These aspects are presented as examples and trade-offs are summarized.

   Simple nine-level inverter with 10 switches and a floating capacitor
By Dohyeon KIM, Jungmin KWON [View]
[Download]

Abstract: This paper presents a simple nine-level inverter with 10 switches and a floating capacitor. The proposed inverter consists of a five-level active-neutral-point-clamped (ANPC) leg and an unfolding leg. The ANPC leg generates a pulsating AC waveform with five voltage levels. The unfolding leg operates at the grid frequency and unfolds the pulsating AC waveform to convert it into a nine-level waveform. Also, a floating capacitor voltage balancing algorithm is introduced to ensure voltage stability. To show the feasibility and performance of the proposed inverter, 1.5 kW prototype is developed.

   Steady-State Analysis and Control of Active Current Injection Based Three-Phase PFC Rectifier
By Ramkrishan MAHESHWARI, Ankur SRIVASTAVA, Prashant SURANA, Thomas EBEL, Lasse Chr. LARSEN, Egon HANSEN [View]
[Download]

Abstract: The paper investigates a boost-integrated current injection-based unity-power-factor three-phase ac-dc converter. It presents a steady-state stress analysis and identifies various circuit modes which are required to design the converter. A simple feedforward controller is proposed and simulated.

   T-type Inverter as a Power-Pulsation Buffer for a PMSM with Large Load Variation
By Pelle WEILER, Toshiyuki FUJITA, Hiroshi FUJIMOTO, Takayuki MIYAJIMA, Yoshiki YASUDA, Akio YAMAGIWA [View]
[Download]

Abstract: This paper presents a modulation strategy for a three-level T-Type inverter to utilize the neutral point as a power-pulsation buffer. The pulsating power of a swing compressor is compensated by the buffer, resulting in dc input power of the motor inverter, despite the varying load. Consequently, the overall drive system can be designed with significantly reduced dc-link capacitance, saving cost and size. Next to theoretical derivation, the proposed modulation strategy is verified in simulation and experiment.

   Three-phase Active-Split source inverter with step-up/step-down DC bus voltage capabilities for traction application
By Antoine SABRIÉ, Alexandre BATTISTON, Jean-Yves GAUTHIER, Xuefang LIN-SHI [View]
[Download]

Abstract: This paper aims at proposing a new single stage DC-AC inverter with both step-up and step-downDC bus voltage capability. For a two-level inverter, the low speed operation points induce low modulation index values and poor efficiency. The proposed topology can operate in a new step-down mode to drive the motor with a DC bus voltage lower than the source for low-speed region, whilestill benefiting of an unaltered step-up function of the DC bus voltage. Meaning that the addition of the step-down function does not induce additional losses during step-up operation. The converter is validated both by simulation and experimentally. In step-down mode, reduced phase current ripple can be achieved, as well as reduced DC-link capacitor temperature.

EPE 2025 - DS2j: AC/DC and DC/AC Converter Topologies
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2025 - Conference > EPE 2025 - Topic 09: Power Converter Topologies > EPE 2025 - DS2j: AC/DC and DC/AC Converter Topologies
	[return to parent folder]

	A Cost-Effective Three Level Shared Leg Flying Capacitor Converter for Switched Reluctance Motors By Ali YOUSEFI DARANI, Nasir ALI, Mehdi NARIMANI	[View] [Download]
Abstract: This paper presents a novel, cost-effective multilevel inverter for switched reluctance motor (SRM) drives. The proposed inverter has a three-level topology with shared-leg flying-capacitor (SLFC) structure. This topology utilizes two shared legs for adjacent phases during the magnetization, freewheeling, and demagnetization of the SRM. This innovative approach reduces the drive's size and cost by reducing the number of power switches, diodes, gate drivers, current and voltage sensors while achieving the same performance as the conventional three-level flying capacitor topology. In comparison to the conventional asymmetric half bridge converter, it improves the performance in terms of current ripple and reduces the voltage stress of some of semiconductors. The feasibility of the proposed three-level SLFC topology is verified through simulation studies based on a three-phase 12/16 SRM drive system.

	A novel Hybrid Inverter Drive for AC motors capable of bypassing the voltage source inverter when operating at grid frequency By Daniel LENDI, Reiko RAUTE, Cedric CARUANA	[View] [Download]
Abstract: Variable speed drives (VSDs) offer reduced power consumption for applications which allowoperation at reduced motor speed. However, when continuous operation at the grid frequencyis required, the VSD may become redundant, as it introduces conversion losses and electromagneticinterference (EMI), in contrast to grid-connected operation. It is hereby proposed to bypass theVSD for continuous operation at the grid frequency. This paper introduces a VSD, based ona two-level voltage source inverter (VSI), capable of transferring a motor load between grid- andinverter-connected operations, depending on the required motor speed. This paper presents athorough analysis of the conditions under which the motor load may be transitioned from eitheroperating mode. Thyristors are used as bypass devices. Simulation results for open and semi-closed transitions are presented, examining their impacts on the motor torque and stator currents.

	A performance comparison between different PWM techniques for the Hybrid Inverter Drive By Daniel LENDI, Reiko RAUTE, Cedric CARUANA	[View] [Download]
Abstract: Variable Speed Drives (VSDs) allow energy savings for loads where operation below the gridfrequency may be required. However, when operating the motor load at the grid frequency,they introduce, compared to grid-connected operation, energy losses and ElectromagneticInterference (EMI). The Hybrid Inverter Drive (HID) offers maximum efficiency at either modeof operation. With the HID the motor load is operated in inverter-driven mode for motorfrequencies below grid frequency and operated in direct grid-connected mode for operation at gridfrequency. This eliminates inverter losses and EMI at the grid frequency. In previous work [5],the HID and its semi-closed transitions were introduced. A performance comparison of theHID operation using pure Sinusoidal PWM (SPWM), Space Vector PWM (SVPWM) and theinjection of the DC-link mid-point voltage into the SPWM reference signals during semi-closedtransitions is presented in this paper. The HID is modelled in MATLAB Simulink.

	Data-Driven RUL Estimation for DC-Link Capacitor in Ultra-Fast EV Charging Systems By Suwaiba MATEEN, Ahteshamul HAQUE, Mohammed Ali KHAN, Thomas EBEL, Shabana MEHFUZ	[View] [Download]
Abstract: The reliability of ultra-fast electric vehicle charging systems heavily depends on the performance of critical components, notably the DC-link capacitor. This paper introduces a data driven approach for estimating the remaining useful life of DC-link capacitors in such systems. A virtual model of the system, developed as a digital twin, integrates real-time operational data with machine learning algorithms trained on historical degradation patterns. Key health indicators, such as a 30\% reduction in capacitance (from 20,000 µF) and a 100\% increase in Equivalent Series Resistance (from 0.4 mO), define the failure thresholds. Simulation-based validation demonstrates the effectiveness of the proposed methodology in accurately predicting capacitor degradation trends. This approach enhances the reliability of high-power EV charging systems and highlights the role of digital twins in predictive maintenance.

	Efficiency and Cost Comparison of GaN/Siand SiC/Si Hybrid ANPC Three-phase Inverter By Manex GONDAT, Ander ÁVILA, Asier GARCIA, Alejandro RUJAS	[View] [Download]
Abstract: This paper evaluates the benefits of a hybrid Active Neutral Point Clamped (ANPC) topology that combines Wide Band Gap (WBG) materials, Gallium Nitride (GaN) or Silicon Carbide (SiC), with Silicon (Si) technologies. The proposed topology enables the integration of GaN semiconductors, typically rated up to 650 V, into 800 V bus applications\_ an input voltage that the automotive market tends to reach. Using hybridization of semiconductor technologies, the system achieves substantial cost reduction without compromising efficiency. The concept is experimentally validated using a 15 kW three-phase prototype.

	Methodology for pre-sizing an MMC by optimization for an aeronautical application By Stéphane NGO BUI HUNG, Cyrille GAUTIER, Lucas PNIAK, Loïc QUÉVAL, Bertrand REVOL, Éric LABOURÉ	[View] [Download]
Abstract: This article presents the pre-sizing of L\_arm, C\_eq components of a 150 kW MMC converter in steady state used as an active rectifier, associated with a variable frequency PMSM generator, and designed to generate an 800 VDC aircraft electrical network. It details the simulation and modelling used and the optimisation process implemented.

	Model Predictive Current Control(MPCC) Using Multi Virtual Voltage Vectors for a Two-Level Inverter in Electric Propulsion Ships By Chan ROH, Hyeon-Gyo CHAE, Eui-Cheol SHIN	[View] [Download]
Abstract: In response to environmental concerns, electric propulsion ships are emerging as a key technology in the maritime industry. The inverter, which controls the propulsion motor, is a critical component in electric propulsion ships. The 2-level voltage source inverter is widely implemented in small and medium-sized ships, but its output performance remains constrained due to limited number of voltage vectors. The proposed approach enables 2-level voltage source inverters to achieve multilevel inverter-comparable performance by adding virtual voltage vectors. While it incurs increased computational burden, the proposed method achieves performance enhancement without computational burden through the application of pre-voltage selection. Experiments have shown improvements in output current THD and current error. The results demonstrate potential advantages for electric propulsion systems.

	Modular multilevel converter based on unipolar-current full-bridge submodules for medium voltage variable speed drive applications By Duro BASIC, Hatim ABBI, Martin GESKE	[View] [Download]
Abstract: With the continuous development of Modular Multilevel Converters (MMC), the introduction of new Sub-Modules (SMs) and their operational characteristics has become favourable for optimizing the performance of many applications such as Variable Speed Drives (VSD), where the conventional ac/dc/ac MMC converters based on Half Bridge (HB) face challenges in low-frequency operation. This paper focuses on the main features of the Unipolar Current (UC) Full-Bridge (FB) SM (UC FB-SM) and benefits of its integration into the MMCs for VSD applications. Basic operation methods of the HB and UC FB based MMCs are analysed and compared, and the duality between their operational modes is highlighted. Main advantages of utilization of the UC FB MMCs in VSD applications are identified and illustrated in the simulation results presented.

	Multi-line input network for class EF inverter with enhanced design flexibility By Baptiste DAIRE, Christian MARTIN, Fabien SIXDENIER, Charles JOUBERT, Loris PACE	[View] [Download]
Abstract: This paper addresses a new input network for the class EF inverter, which utilizes multiple transmission lines instead of the commonly used quarter-wave line. Experimental demonstrations at 15 MHz with 40 W output power are conducted, showcasing that enhanced performance can be achieved with the proposed input network.

	Operation modes and design consideration for MMC with unipolar current full-bridge submodules By Martin GESKE, Hatim ABBI, Duro BASIC	[View] [Download]
Abstract: The unipolar current full-bridge submodule (SM) for modular multilevel converters (MMC) operates with unipolar current and bipolar voltage. Two basic operating modes for unipolar arm currents are presented, described, and analyzed. The differences between the two idealized operating modes are further discussed regarding the system design of an MMC. The design factors for current and voltage in the DC-link differ, which leads, for example, to different numbers of SMs and power losses. These aspects are presented as examples and trade-offs are summarized.

	Simple nine-level inverter with 10 switches and a floating capacitor By Dohyeon KIM, Jungmin KWON	[View] [Download]
Abstract: This paper presents a simple nine-level inverter with 10 switches and a floating capacitor. The proposed inverter consists of a five-level active-neutral-point-clamped (ANPC) leg and an unfolding leg. The ANPC leg generates a pulsating AC waveform with five voltage levels. The unfolding leg operates at the grid frequency and unfolds the pulsating AC waveform to convert it into a nine-level waveform. Also, a floating capacitor voltage balancing algorithm is introduced to ensure voltage stability. To show the feasibility and performance of the proposed inverter, 1.5 kW prototype is developed.

	Steady-State Analysis and Control of Active Current Injection Based Three-Phase PFC Rectifier By Ramkrishan MAHESHWARI, Ankur SRIVASTAVA, Prashant SURANA, Thomas EBEL, Lasse Chr. LARSEN, Egon HANSEN	[View] [Download]
Abstract: The paper investigates a boost-integrated current injection-based unity-power-factor three-phase ac-dc converter. It presents a steady-state stress analysis and identifies various circuit modes which are required to design the converter. A simple feedforward controller is proposed and simulated.

	T-type Inverter as a Power-Pulsation Buffer for a PMSM with Large Load Variation By Pelle WEILER, Toshiyuki FUJITA, Hiroshi FUJIMOTO, Takayuki MIYAJIMA, Yoshiki YASUDA, Akio YAMAGIWA	[View] [Download]
Abstract: This paper presents a modulation strategy for a three-level T-Type inverter to utilize the neutral point as a power-pulsation buffer. The pulsating power of a swing compressor is compensated by the buffer, resulting in dc input power of the motor inverter, despite the varying load. Consequently, the overall drive system can be designed with significantly reduced dc-link capacitance, saving cost and size. Next to theoretical derivation, the proposed modulation strategy is verified in simulation and experiment.

	Three-phase Active-Split source inverter with step-up/step-down DC bus voltage capabilities for traction application By Antoine SABRIÉ, Alexandre BATTISTON, Jean-Yves GAUTHIER, Xuefang LIN-SHI	[View] [Download]
Abstract: This paper aims at proposing a new single stage DC-AC inverter with both step-up and step-downDC bus voltage capability. For a two-level inverter, the low speed operation points induce low modulation index values and poor efficiency. The proposed topology can operate in a new step-down mode to drive the motor with a DC bus voltage lower than the source for low-speed region, whilestill benefiting of an unaltered step-up function of the DC bus voltage. Meaning that the addition of the step-down function does not induce additional losses during step-up operation. The converter is validated both by simulation and experimentally. In step-down mode, reduced phase current ripple can be achieved, as well as reduced DC-link capacitor temperature.