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This paper presents a method to control the ground current in a back‐to‐back connection of three‐phase T‐type rectifier and inverter stages if operated from a three‐phase mains with a grounded neutral point and a star‐connected three‐phase load with grounded star point. The proposed control scheme requires a ground current sensor and a single control loop, achieves a closed‐loop control system bandwidth...
Multi-level topologies reduce the requirements on inductors and filters, however, given the high number of series connected semiconductors, it is still unclear if they are a suitable option to achieve ultra-high efficiency while maintaining a reasonable power density. For this purpose, an extensive quantitative evaluation of different topologies is carried out, to determine the required volume for...
Integrated Voltage Regulators (IVRs) have become a viable solution for microprocessor's power delivery. The active parts of the most recent IVRs are built in deep-submicron CMOS technologies and use stacked transistors to allow for the use of advanced low voltage devices with superior switching performance compared to the higher voltage long-channel devices. This paper evaluates three different topologies...
State-of-the-art high power density AC/DC and DC/AC converter systems typically employ Triangular Current Mode (TCM) modulation or conventional PWM. TCM is characterized by a wide variation of switching frequency over the mains period and ensures soft-switching in all operating points, but results in increased conduction and high-frequency losses due to the necessary large current ripple. In contrast,...
Modern GaN and SiC power semiconductors require new experimental methods for determining switching losses as the widely accepted double-pulse-test (DPT) fails to accurately capture the dissipated energy during a switching transition because of electrical measurement limitations imposed by the very fast switching of WBG devices. In this paper, a new calorimetric measurement principle which relies on...
DC power distribution systems for data centers, industrial applications and residential areas are expected to provide higher efficiency, reliability and lower cost compared to ac systems. Accordingly they have been an important research topic in recent years. In these applications an efficient power factor correction rectifier, supplying a dc distribution bus from the conventional three-phase ac mains...
Due to the increasing power consumption of data centers, efficient dc power distribution systems have become an important topic in research and industry over the last years. Furthermore the power consumed by data centers is an economic factor, which implies that all parts of the distribution system should be designed to minimize the life cycle cost, i.e. the sum of first cost and the cost of dissipation...
For the power management of a wireless power transfer system for implantable mechanical heart pumps, an additional boost DC-DC converter stage is needed in order to control the power delivered to the implant. Particularly, battery powered and implantable medical devices pose special demands on the efficiency and/or power density of the employed converters. Accordingly, soft-switching and/or high switching...
In high power density single-phase PV inverter systems, active auxiliary circuits are installed, shifting the double line-frequency power pulsation away from the dc link to a dedicated buffer capacitor. Being relieved from strict voltage ripple requirements, a larger voltage ripple is allowed at the buffer capacitor, significantly reducing the capacitance requirements and consequently the overall...
There is an ongoing demand for increased power density and efficiency along with lower costs of converter systems and shorter development time for specific applications in the field of power electronics. In order to expedite the technology development Google and IEEE initiated the Google Little Box Challenge (GLBC) including $1 million prize money. Aim of the GLBC was to build the worldwide smallest...
In single-phase power conversion systems, typically bulky electrolytic capacitors are installed in order to cope with the intrinsic double-line frequency power pulsation. However, since the voltage ripple at the dc bus is typ. limited to just a few percent of the nominal voltage, only a small fraction of the actually stored energy in the capacitors is used for the power decoupling. In this paper an...
Two important aspects of switched-mode (Class-D) amplifiers providing a high signal to noise ratio (SNR) for mechatronic applications are investigated. Signal jitter is common in digital systems and introduces noise, leading to a deterioration of the SNR. Hence, a jitter elimination technique for the transistor gate signals in power electronic converters is presented and verified. Jitter is reduced...
In three-phase pulse width modulation inverters with an LC output filter, switching losses can be reduced by increasing the current ripple in the inductor until a current zero crossing occurs between the two switching instances of a bridge leg. A disadvantage of this triangular current mode (TCM) operation is the varying switching frequency. This paper presents new modulation methods where the current...
Inductive power transfer technology has proven to be a promising solution for powering implantable heart pumps such as left ventricular assist devices, eliminating the need for a percutaneous driveline and reducing the risk of severe infections significantly. However, the required high power transfer capability of a Transcutaneous Energy Transfer (TET) system raises questions about human safety regarding...
The semiconductor industry demands for pumps which handle aggressive fluids at very high temperatures, as this is an important step towards higher process speeds and increased yield in semiconductor etching applications. This paper presents the thermal, electrical and mechanical design of a bearingless pump for operating temperatures of up to 250 ° C without active cooling. A detailed thermal analysis...
Power amplifiers providing an output current of high precision, high bandwidth and low distortion are required in different fields like magnetic resonance imaging or motion control systems for semiconductor production processes. This paper analyzes different power stage implementations of switched-mode (Class-D) amplifiers intended for such applications. They are preferred to linear or hybrid solutions...
This paper describes a new modulation concept for the uni- and bidirectional SWISS rectifier which mitigates input current distortions at the gird voltage sector boundaries. An analytical model is derived and compared to simulations, showing that these distortions are increasing the input current THD significantly. Furthermore, an algorithm is presented which allows the calculation of a temporary...
This paper introduces a phase-oriented control strategy for the uni- and bidirectional three-phase, bucktype SWISS Rectifier. It allows phase shifted sinusoidal input currents which enable the generation of capacitive or inductive reactive power at the converter's AC grid interface. Furthermore, the operation of the SWISS Rectifier with unsymmetrical AC mains voltages is analyzed. Modifications of...
Silicon-carbide semiconductor technology offers the possibility to synthesize power devices with unprecedented blocking voltage capabilities while achieving outstanding switching and conduction performances. Accordingly, this new semiconductor technology is especially interesting for Solid-State Transformer concepts and is utilized in this paper for designing a 25 kW/50 kHz prototype based on 10 kV...
This paper details efficiency optimized operation and design of a bi-directional and isolated five-level Dual Active Bridge (5LDAB) converter for an application that requires ultra-wide voltage and power ranges. The rated power of the considered converter is 7.5kW, the specified input voltage range is 150V ≤ Vdc1 ≤ 800V and the output voltage is constant, Vdc2 = 700V. In order to achieve high efficiency...
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