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This paper presents the capacitor size reduction of a MMC-based transformer-less STATCOM for medium voltage ac distribution system. The instantaneous power swinging flows into the single-phase configuration results in a high capacitance needed; however, by accepting the swinging voltage in the capacitor, the capacitance can be drastically reduced. This paper analyzes the dimensional size reduction...
A novel contactless power supply system for electric trains is proposed based on structure of an air gapped coaxial transformer. Theoretical analysis, simulation results and verification experiments were conducted and the results are shown in this paper. The 96.9 % efficiency at 125 W was observed with an air gap (2.5 mm) coaxial structure. It was conducted that traction power was delivered by coaxial...
Resonant converters find widespread application in the industries for Radio Frequency (RF) heating. Various topologies using vacuum tubes are currently used for such application. Realizing class D topologies with solid state devices could provide more reliability. This work explores possibility of developing a 1kW Class D resonant converter for heating applications using Si/SiC MOSFETs which can replace...
The miniaturization trend of electric machines increases the demand for higher rotational speeds to provide a desired mechanical power level at decreased size. To push the limits of rotor miniaturization, new concepts for an ultra-high speed motor are researched, which employs sub-millimeter size rotors and is capable of achieving rotational speeds above 25 million rotations per minute (Mrpm). The...
This paper proposes the outline design of a platform that can be used to implement multiple emulators to replicate the behaviour of different energetic resources, storage systems, loads or electric grids. This platform can be used to test control algorithms of microgrids with different elements connected into it.
Contactless power transfer (CPT) has demonstrated its ability as a safe, efficient and convenient way for electric vehicle (EV) charging systems by providing acceptable power levels with tolerance to misalignments. The magnetic design of the primary and secondary coupler is one of the most critical parts of a CPT system design. This paper investigates various configurations of loosely coupled magnetic...
Distributed generation via residential branches connected to DC buses are going increased considered an open energy system. These residential branches DC buses have a lot of different shapes forming several types. One of these types is using photovoltaic PV and battery storage system (BSS) connected to main DC bus or multi-terminal DC (MTDC) buses. Recently, this is named DC nanogrid interconnected...
In this paper, we present a new generation of Nanocrystalline magnetic cores (kμ) with low permeability. The magnetic properties of kμ magnetic cores will be compared to other magnetic cores which have the same range of relative magnetic permeability. The kμ magnetic cores allow magnetic core volume (resp. core mass) to be reduced by up to 5.5 times (resp. by up to 3 times) compared to Ferrite magnetic...
In this paper, a detailed model of a 2 MW wind turbine system with a permanent magnet synchronous generator (PMSG), including the aerodynamics, the mechanics, and the electrical domain is presented. It is then used to examine the influences of the level of detail in the model of a wind turbine system on the calculated lifetime consumption of the converter's power modules. This is done by comparing...
Due to the increasing number of power-electronic components connected to the grid, medium-voltage dc (MVDC) grids are a promising alternative to established ac distribution grids. Within this work, the advantages and additional flexibility of substations for (urban) railways connected to future MVDC distribution grids are investigated. Possible topologies are presented and the efficiencies are compared.
A simple and low cost quasi resonant LED driver is proposed. Prominent merits of the proposed topology are low line current distortion and reduced switch voltage stress. This paper presents the principle of operation of the proposed circuit, analysis of average power and switch voltage and current stress. Theoretical predictions are supported by simulation and experiment.
This paper explains a procedure on how to select resonant circuit components of a unique direct three-phase to single-phase AC/AC converter for a contactless electric vehicle (EV) charger. The topology has a fewer bi-directional switches than a matrix converter and consists of a resonant circuit to utilize a zero-current switching (ZCS) mechanism. The selection goal was to realize a working prototype...
This paper deals with the estimation of the lifetime consumption of power semiconductor modules due to power cycling with regard to a 125 kW photovoltaic inverter. The described calculation model takes into account a demanding photovoltaic mission profile, the operating point dependent behavior of the photovoltaic inverter, the amount of parallel semiconductor chips and the cooling system design....
Copper metallization and copper wire bonding of high power semiconductor devices have attracted growing attention in recent years due to potentially much improved reliability and increased lifetime. However, significant technical challenges still remain for its wide commercial use. Here a thick copper layer has been successfully grown onto 3300V fast recovery diodes and subsequently 16mil copper wires...
This paper presents a novel hybrid modular multilevel voltage source converter suitable for HVDC applications. It has the advantages of other modular multilevel topologies and can be made more compact making it attractive for offshore stations and city infeed applications. The Operating principle of the converter and internal energy management are discussed with simulation results from a scaled medium...
This paper presents a test bench for lifetime investigation of 10 kV silicon carbide power modules. The test bench subjects high voltage switching operation to the modules while power cycling. Thus both a thermal and electrical operating point is emulated. The power cycling setup features offline measurement of on-state voltages and direct real-time measurement of die surface temperatures, enabled...
This paper presents the results of a system study comparing a SiC MOSFET and a Si IGBT power module on a DC/DC power conversion system level. The target of this study is the evaluation of a reduced cooling effort as well as the reduction of inductor sizes by the use of high efficient SiC switches. Therefore a conversion performance target have been defined which have to be fulfilled by the SiC and...
This paper presents the concept and characterization of a NPC1 phase leg built up out of three PrimePACK™ 2 power modules with .XT and 1200 V IGBT5. The target application of such a topology is 1500 V solar central inverter. After a short description of the cosmic ray reliability issues leading to the NPC1 approach, different design concepts will be discussed. Double pulse measurements have been used...
Multi-converter systems composed of series or parallel connected modular multilevel converters (MMCs) require a means to manage power sharing between the MMCs by balancing the load during operation. Series connected MMCs require proper voltage balancing while parallel connected MMCs require proper current balancing. The paper describes this imbalance phenomenon, illustrates the solution via simulation...
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