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Dc electric railway is one of the important application fields of low voltage dc power supply. The reliability analysis of each component in dc power supply system in East Japan Railway Company whose voltage level is dc 1.5kV was carried out. Such quantitative analysis can realize reasonable proposal of redundant dc circuit configuration. In this paper, the relation between the redundant configuration...
Paper is presenting application of synchronized power flow measurement system within 13 locations of DC microgrid installation in production plant with specific measurement equipment system developed for dynamic energy flow analysis. Insight into internal DC bus power exchange behavior and interconnected operation advantages with respect to energy efficiency improvement is provided. Future trends...
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.
We, East Japan Railway Company, have already installed three energy storage systems in d.c. railway power supply system around Tokyo area for regenerative energy utilization and are now constructing new regenerative inverter system at Tokyo Station. In this paper, advantages and disadvantages of those systems will be compared. Furthermore, the examples of load waveforms of traction power supply system...
This paper presents a design and construction of an integrated magnetic element IME to achieve high efficiency and high power density in 1250 W LLC resonant converter. Superposition of two magnetic inductions oriented antiparallelly in the chosen areas of IME allows reduction of the volume required for inductive elements, increased coefficient of transferred power to volume [W/dm3] and reduction of...
This paper shows that the ZETA-SEPIC converter can be used as a bidirectional charging system between a high DC link voltage and a low voltage battery system. Main advantages are transformerless operation and that the coupling capacitor protects and separates both sides of the converter in case of short circuits.
A helical-type fusion facility uses a large-scale superconducting DC magnet. To maintain the coil current of this magnet during steady-state operation, a large output current supplied by a very-low-voltage power supply is necessary. For this purpose, a DC power supply using a mechanical contact as a switching device was designed, and a small model of the contact was tested.
This paper presents an adaptive slope compensation method for peak current mode control of digital controlled DC-DC converters, which controls the quality factor of the complex conjugated poles at half the switching frequency. Using quality factor control enables optimization of the dynamic performance and stability of current mode control. The presented method adapt to DC-DC converter operating conditions...
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.
This paper presents a protection scheme for a medium voltage dc (MVDC) link, that meshes three different MVAC distribution grids through ac/dc power converters. The proposed scheme includes active current limiters, hybrid circuit breakers and a communication layer for the coordination of these protection devices and power converters (logic selectivity). Active current limiters, installed just after...
The transient performance of a DC power supply strongly depends on the loop design and output filter sizing. Most of the time, the finite loop bandwidth imposes the need of a large output filter capacitor in order to comply with the required regulation performance and stability margins. In space applications the linear conductance control principle has been used for a long time. It reduces the voltage...
This paper presents an interleaved multiphase hybrid buck-boost DC/DC converter. This converter type provides high efficiency and can be used for applications with wide voltage conversion ratio. At the beginning, the circuit function and the design of a single-phase converter is described. With a multiphase design, the filter circuit effort can be significantly reduced. In these circuits the different...
This paper describes the design of a DC grid as a utility grid of a business park. The center of the DC grid is a DC substation. The DC substation is supplied from the MV AC grid. With a transformer and an Active Front-End, the AC voltage of 10 kV is transformed into 750 VDC. At customer side, the 750 VDC is converted to the required DC voltage for his application.
The realization of wide input voltage and high power density on the conventional current resonant converter such as LLC converter remarkably increases transformer winding loss and its design difficulty. Therefore, it is difficult for the conventional LLC converter to satisfy both requirements. In order to apply the LLC converter with both conditions, this paper investigates the mechanism of the transformer...
A transformerless multicellular dc-dc converter has been newly proposed. The capacitively isolated dc-dc cell converters have been applied to develop the multicellular converter without using high frequency transformers. The high voltage transformation ratio is achieved by the ISOP (Input Series Output Parallel) connection topology of the cell converters and the realization of the highly efficient...
In this paper, a high performance fully digital peak current mode controller for DC-DC converters which supports the full duty cycle range from 0–100% is presented. Support for low duty cycle is very important during short circuit or converter overload and support for high duty cycle is important for faster response during a transient and for providing a larger output voltage range. The digital current...
Recently introduced Bi-directional Z-Source breakers [1] are capable of clearing the short circuit fault within a few microseconds. In this paper, various applications and protection requirements for Bidirectional Z-Source breakers are discussed. Detailed comparison between de-rated AC breakers and Z-Source breakers is discussed. Breaker design criteria are explained with the help of simulation results...
A control algorithm for an integrated power factor correction (PFC) and series resonant converter (SRC) using only two switches is presented, allowing to open loop control the AC input current and the DC output current independently. The theory for this approach is analyzed in time domain and a novel approach for open loop regulation is presented and verified. The software defined power (SDF) control...
This paper presents a high power density coupled tape-wound inductor consisting of nano-crystalline material used in a DC/DC converter. In a first step the comparison of the 2-phase coupled inductor (CI) with the 2-phase interleaved converter (SII) is presented. Second step is designing the CI ρ/η-pareto analysis. To test the device a high power density SiC-converter is designed. The experimentally...
This paper proposes the novel generation method of gate signals to control output voltage in a wide range and to achieve synchronous rectification operating in half-bridge LLC resonant converters. The switching frequency modulation is used in half-bridge LLC resonant converters for control strategy of output voltage. The switching timing of secondary MOSFETs is compensated using the gate signal of...
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