A highly efficient DC-DC-converter for medium-voltage applications

Thoma, Jurgen; Chilachava, David; Kranzer, Dirk

doi:10.1109/energycon.2014.6850417

Cited by 17 publications

(6 citation statements)

References 4 publications

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“…To achieve a load-independent voltage transfer ratio, the resonance capacitors have to be dimensioned as [53]: (2) In this operating point (which is slightly above the resonance), the phase angle of the input impedance seen by the fullbridge is (3) and hence guarantees ZVS operation of the MOSFETs due to the inductive behavior [53]. Furthermore, due to this particular compensation method, the primary-side rms current is independent of the inductances, the magnetic coupling, and the operating frequency, and can be calculated as 4The secondary-side current is ideally in phase to the rectangular voltage applied from the rectifier and its rms value can be calculated as (5)…”

Section: A Isolated Power Supply Topologymentioning

confidence: 99%

Highly Compact Isolated Gate Driver With Ultrafast Overcurrent Protection for 10 kV SiC MOSFETs

Rothmund¹,

Bortis²,

Kolar³

2018

CPSS TPEA

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Section: A Isolated Power Supply Topologymentioning

confidence: 99%

Highly Compact Isolated Gate Driver With Ultrafast Overcurrent Protection for 10 kV SiC MOSFETs

Rothmund¹,

Bortis²,

Kolar³

2018

CPSS TPEA

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“…At 50 % load, the efficiency is still 98.8 %, making the converter also suitable for partial load operation. Comparing these values to existing 10 kV or 15 kV SiC MOSFET-based topologies [16]- [20], a significantly higher efficiency, switching frequency and thus power density are achieved by the iTCM converter due to ZVS.…”

Section: A Experimental Resultsmentioning

confidence: 89%

“…Due to the high blocking voltage of the utilized 10 kV SiC MOSFETs, a simple full-bridge-based PWM AC/DC converter topology is chosen. However, without further measures, hardswitching and thus high switching losses would occur [16]- [20]. Consequently, the achievable efficiency and power density would be strongly restricted, since the switching losses define an upper limit for the switching frequency, and hence inhibit a possible downsizing of passive components.…”

Section: Introductionmentioning

confidence: 99%

99.1% Efficient 10 kV SiC-Based Medium-Voltage ZVS Bidirectional Single-Phase PFC AC/DC Stage

Rothmund

Guillod

Bortis

et al. 2019

IEEE J. Emerg. Sel. Topics Power Electron.

103

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Due to their extremely high energy demand, data centers are directly supplied from a medium voltage (MV) grid. However, a significant part of this energy is dissipated in the power supply chain, since the MV is reduced step-by-step through multiple power conversion stages down to the chip voltage level. In order to increase the efficiency of the power supply chain, the number of conversion stages must be substantially reduced. In this context, Solid-State Transformers (SSTs) are considered as a possible solution as they could directly interface the MV AC grid to a 400 V DC bus, whereby server racks with a power consumption of several tens of kilowatts could be directly supplied from an individual SST. With a focus on the lowest system complexity, the SST ideally should be built as simple two-stage system consisting of an MV AC/DC PFC rectifier stage followed by an isolated DC/DC converter. Accordingly, this paper focuses on the design and realization of a 25 kW, 3.8 kV single-phase AC to 7 kV DC PFC rectifier unit based on 10 kV SiC MOSFETs. By simply adding an LC-circuit between the switch nodes of the well-known full-bridge-based PWM AC/DC rectifier, the integrated Triangular Current Mode (iTCM) concept is implemented, which only internally superimposes a large triangular current ripple on the AC mains current and therefore enables zero voltage switching (ZVS) over the entire AC mains period. Special attention is paid to the realization of the MV inductors and their electrical insulation, the AC-input LCL-filter to limit EMI emissions, and the challenges arising due to cable resonances when connecting the SST to the MV grid via a MV cable. Despite the large insulation distances required for MV, the realized 25 kW MV PFC rectifier achieves an unprecedented power density of 3.28 kW/L (54 W/in 3 ) and a full-load efficiency of 99.1 %, determined using a calorimetric measurement setup, which is discussed in detail in the Appendix.

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“…These devices are only available in bare die form, and recent research has been focused on the development of highvoltage packaging of such devices. Several research teams have investigated and demonstrated the fast switching capabilities of the 10 kV SiC MOSFETs mainly in hard-switched double-pulse tests [21][22][23][24][25], short-circuit characteristics [26][27][28], DC-DC converters [29][30][31][32] and inverter demonstrators with frequencies up to 40 kHz [33][34][35][36][37]. There has not yet been any documented attempts at operating 10-15 kV SiC devices in the MHz range.…”

Section: Introductionmentioning

confidence: 99%

High‐frequency resonant operation of an integrated medium‐voltage SiC MOSFET power module

Jørgensen

Aunsborg

Bęczkowski

et al. 2020

IET Power Electronics

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Industrial processes which use induction and dielectric heating are still relying on resonant converters based on vacuum tubes. New emerging medium-voltage silicon carbide (SiC) semiconductor power devices have a potential to replace vacuum tubes and allow for more efficient and compact converters in the high-frequency range. High-voltage packages have been proposed in the literature that are suitable for the 10 kV SiC metal-oxide-semiconductor field-effect transistors (MOSFETS), and its fast voltage switching capabilities in hard-switched applications have been demonstrated. However, no packaging is presented which allows the high-frequency operation of a 10 kV SiC MOSFET die. This study proposes the design of a power module for MHz resonant operation of a 10 kV SiC MOSFET. At high switching frequencies, the gate losses become substantial, thus the gate driver is included inside the power module package to ensure a low inductive and high thermally conductive design as seen from the gate driver. The inductance of the proposed power module layout structure is evaluated using ANSYS Q3D Extractor. The thermal performance of the integrated gate-driver circuitry is experimentally verified. Finally, the resonant operation of a medium-voltage SiC MOSFET power module is demonstrated experimentally at 1 MHz.

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A highly efficient DC-DC-converter for medium-voltage applications

Cited by 17 publications

References 4 publications

Highly Compact Isolated Gate Driver With Ultrafast Overcurrent Protection for 10 kV SiC MOSFETs

Highly Compact Isolated Gate Driver With Ultrafast Overcurrent Protection for 10 kV SiC MOSFETs

99.1% Efficient 10 kV SiC-Based Medium-Voltage ZVS Bidirectional Single-Phase PFC AC/DC Stage

High‐frequency resonant operation of an integrated medium‐voltage SiC MOSFET power module

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