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Dual-Inverter Topology for Single-Phase Supplied Drive Systems without Electrolytic Capacitor
(2021)2021 24th International Conference on Electrical Machines and Systems (ICEMS)Single-phase supplied variable speed drive (VSD) systems are widely used in industrial applications and typically feature a two-stage design with a power factor corrected (PFC) boost rectifier and a three-phase voltage source inverter (VSI). However, the electrolytic DC-link capacitor, which is needed to cope with the twice grid frequency power pulsation, and the required boost inductor are unfavourable in terms of reliability, volume, ...Conference Paper -
Quad-Port AC-DC-DC-AC Operation of Isolated Dual Three-Phase Active Bridge Converter
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)This paper investigates the operation of the Dual Three-Phase Active Bridge (D3AB) converter topology as a multi-port converter, by taking the three-phase ac port and dc port on the primary side (ac(1) and dc(1)) and the galvanically isolated three-phase ac port and dc port on the secondary side (ac(2) and dc(2)) simultaneously into account. The basic working principle of the D3AB topology under multi-port operation and a strategy to ...Conference Paper -
Design and Characterization of a Bearingless Cross-flow Fan
(2021)2021 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM)This paper presents a high-speed bearingless cross-flow fan particularly suited for applications in chemically demanding environments. In general, bearingless motors convince with a friction-and wear-free operation, unlimited lifetime and a hermetically-sealed encapsulation of the rotor. For the proposed cross-flow fan, a double-sided use of such motors additionally leads to twice the available torque for the blade rotation as well as a ...Conference Paper -
Comparative Evaluation of Three-Phase AC-AC Voltage/Current-Source Converter Systems Employing Latest GaN Power Transistor Technology
(2022)2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia)The emergence of monolithic bidirectional GaN power transistors sparks renewed interest in AC-AC current source converters (CSCs) as an alternative to AC-AC voltage source converters (VSCs) for motor drive applications. This paper compares the two approaches with the CSC utilizing novel 600 V, 140 m Omega monolithic bidirectional CaN transistors. Aiming for a comparison of next-generation plug-and-play motor drives, both systems must ...Conference Paper -
Comparative Evaluation of MVAC-LVDC SST and Hybrid Transformer Concepts for Future Datacenters
(2022)2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia)A transition from state-of-the-art 400 V AC to 690 V AC or 800 V DC (+/- 400 V DC) distribution improves the overall power conversion efficiency of datacenter power supply systems. The latter requires megawatt-level isolated medium-voltage (MV) AC to low-voltage (LV) DC conversion stages that operate with an efficiency of at least 98 AD. Whereas today's most advanced industrial MVAC-LVDC solid-state transformer (SST) prototypes do achieve ...Conference Paper -
Application of WBG Power Devices in Future 3-Φ Variable Speed Drive Inverter Systems "How to Handle a Double-Edged Sword"
(2020)2020 IEEE International Electron Devices Meeting (IEDM)Latest research results on three-phase wide-bandgap (WBG) inverter systems with full-sinewave output voltage filtering are reported. A new soft-switching modulation scheme for two-level 1200 V SiC inverters is described. Furthermore, a new Figure-of-Merit for determining maximum multi-level (ML) bridge-leg efficiency is defined and low-voltage GaN devices are evaluated considering ML flying capacitor (FC) and multi-cell inverter structures. ...Conference Paper -
High-Bandwidth High-CMRR Current Measurement for a 4.8MHz Multi-Level GaN Inverter AC Power Source
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)The control of very high switching frequency power electronic converter systems featuring latest generation wide bandgap (WBG) devices requires current measurements with a very high bandwidth (BW) to achieve high closed-loop control dynamics. One example is a ultra-high BW 4.8 MHz parallel-interleaved multi-level GaN inverter AC power source with a target output BW of 100 kHz. This work investigates the combination of state-of-the-art ...Conference Paper -
Comparative Evaluation of Overload Capability and Rated Power Efficiency of 200V Si/GaN 7-Level FC 3-Φ Variable Speed Drive Inverter Systems
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)Variable speed drive systems in e.g. robotics applications are challenged with discontinuous operation cycles and short-time overload current requirements of 2-3 times nominal load. As the motor itself constitutes a large thermal time constant compared to the semiconductor devices in the inverter, latter create a bottleneck for the increased losses during overload operation. Hence, special focus has to be laid on the inverter overload ...Conference Paper -
Single-Phase Full-Power Operable Three-Phase Buck-Boost Y-Rectifier Concepts
(2021)2021 IEEE Applied Power Electronics Conference and Exposition (APEC)Future electric vehicle chargers should feature full nominal output power in single-phase (1-Phi) and three-phase (3-Phi) operation, such that they can be employed in the USA as well as in Europe. Further, the converter system should have buck-boost capability to cover a wide DC output voltage range in order to provide compatibility with various nominal battery voltage levels. The phase-modular Y-Rectifier consists of three buck-boost ...Conference Paper -
Control and Protection of a Synergetically Controlled Two-Stage Boost-Buck PFC Rectifier System under Irregular Grid Conditions
(2020)2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia)There is an increasing demand for three-phase mains interfaced high power EV chargers that provide a wide output voltage range while featuring low losses and a high power density. In this context, a synergetic control structure for a two-stage three-phase boost PFC rectifier with subsequent DC/DC buck stage was proposed, which allows to only switch one out of the three rectifier bridge legs, leading to switching loss savings of over 66 ...Conference Paper