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An improved modulation algorithm is proposed for three-phase face-to-face topology. The algorithm could make the face-to-face dc transformer use 1: 1 ac transformer or omit ac transformer in a wide variable ratio range to reducing the volume of the system. The simulation in MATLAB/Simulink validates the proposed algorithm.
The implementation of 15 kV Silicon Carbide (SiC) MOSFETs in a three-phase, three-level active power filter of 100 kVA for a 10 kVAC grid and their challenges is shown. Due to the high switching frequency of 16 kHz, respectively 32 kHz ripple frequency, it will perfectly suited for active filtering of harmonics in the medium voltage grid.
This paper presents an algorithm for determining fault section on Modular Multilevel Converter (MMC) based hybrid High Voltage DC (HVDC) transmission system. The hybrid transmission system consists of an overhead line followed by a subsea cable for deep-water oil and gas processing. The algorithm is based upon independent analysis of post fault characteristic signals at each terminal. These characteristic...
This paper presents a concept for a compact high voltage generator based on a highly integrated power chain switching at frequencies above 500 kHz. The high frequency operation in combination with the high integration approach enable a reduction of volume and weight of HY-generators used in industrial or medical applications.
There are problems with insulation failures in high-voltage transformers due to fast transient voltages. Within novel Solid-State Transformers (SST) this problem exists constitutionally because of the SSTs rectangular working voltages. Experiments and simulations have been performed to get accurate understanding of the phenomena. The results and theories are discussed in this paper.
This paper presents the use of innovative high-voltage SiC diode technology in the development of a user configurable full-wave or half-wave rectifier bridge. The devices are of merged Junction-Barrier-Schottky (JBS) type to enable for optimum performance even in the presence of current surges, as demanded by the application. To contain the cost of the proposed solution, their packaging relies on...
The article describes a feedback Preisach hysteresis model equivalent circuit implementation of a medium frequency single-phase transformer being a part of a high power and high efficiency DC-DC converter. The macroscopic models of magnetic hysteresis are introduced and the feedback Preisach model is selected for further analysis. The hysteresis model is developed for a prototype transformer and the...
The paper describes a compact high-voltage pulse generator for supplying the non-thermal plasma reactors for sterilizing powdered spices. Built and investigated converter generates a high voltage pulses of 35kV in amplitude and 70kW in a peak. The first part of the article presents an analytical description of Tesla transformer. Next part describes topology based on Tesla transformer with a toroidal...
This paper presents a galvanically isolated two channel measurement system for voltage and current measurement in medium-voltage dc-dc converters with more than 1 kV operating voltage. The system uses delta-sigma modulation and signal multiplexing to transmit the digitalized signals over fiber optical cables. In combination with a current-loop power supply, high noise immunity and excellent electrical...
Constant random and wear-out failures of sub-modules (SM) within a Modular Multi-level Converter (MMC) are examined. Constant random failures are calculated using the binomial distribution formula, using a constant failure rate. Wear-out failures are calculated using discrete Markov chain modelling and Monte Carlo estimation, with the failure rate of a SM increasing with time. The results are compared...
Dielectric Barrier Discharge (DBD) reactors are widely used for industrial ozone generation. Paper presents impact of voltage shape of different power supply topologies for DBD on ozone efficiency production. Results of five voltage shapes of three different power supply topologies were presented and discussed. Investigation shows that selection of voltage shape and as a result power supply topology...
This paper analyzes the design and construction of a SiC-based Dual Active Bridge (DAB) converter for its use in a three-stage Power Electronic Transformer (PET) based on a Modular Multilevel Converter (MMC). The galvanic isolation between primary and secondary of the PET provided by the DAB High Frequency Transformer (HFT) is 24 kV. Challenges for the HFT design are discussed. A 5 kW DAB prototype...
This paper is introducing a new method of operation for a series resonant converter, with intended application in megawatt high voltage DC wind turbines. Compared to a frequency-controlled series resonant converter operated in sub-resonant mode, the new method (entitled pulse removal technique) allows the transformer design to be determined by peak load and maximum switching frequency, while still...
Four DC/DC converters are analyzed and compared with respects to availability, efficiency, ratings, repair costs and power density. Intended application is offshore wind farms with MVDC power collection. The selected topology is a new series resonant converter, which offers 99% efficiency across the entire operational range, but needs components designed for high voltage stress.
High-density packaging of fast-switching power semiconductors typically requires low parasitic inductance, high heat extraction, and high thermo-mechanical reliability. High-density packaging of high-voltage power semiconductors, such as 10 kV SiC MOSFETs, also requires low electric field concentration in order to prevent premature dielectric breakdown. Consequently, in addition to the usual electromagnetic,...
This paper presents the verification of a concept of operation and the in-depth analysis of the bidirectional multilevel switched capacitor converter with high voltage ratio and strongly limited stresses of switches. These features as well as efficiency and effective voltage ratio are investigated analytically by simulations and experiments presenting many original results.
The voltage balancing of the dc-link capacitors in an electric drive system with five-level neutral-point-clamped converters is investigated in this paper. A properly modified space-vector-modulation technique is utilized in combination with a multilevel dc/dc converter for controlling the capacitor voltages. An advanced algorithm has been developed for reducing the losses of the electric drive system...
The paper describes the design methodology of a novel Triple Active Bridge cell used as the building block for modular DC-DC converters. The intended application is for Medium Voltage Direct Current grids, such as the DC collector for offshore wind farms. The latest generation of SiC MOSFET semiconductors is utilized to operate in the medium frequency range while optimizing the efficiency. The dimensioning...
This paper introduces the fault behavior of full bridge modular multilevel converters (MMCs) considering a non-simultaneous blocking of the two half bridges in each sub-module. In order to protect IGBTs in the full bridge sub-module, both sides of a full bridge sub-module are not blocked at same time point. It is assumed that the first blocking of both sides is random in each sub-module, so there...
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