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Medium and high frequency, high power transformers play an important role in footprint reduction along with their functions of galvanic isolation, and voltage transformation in all high power converters typically used in traction power systems, offshore wind plant power converters, and solid state transformer based distribution system grids. This state of art report analysis the various materials...
This paper proposes a voltage clamping balance (VCB) with hysteresis charging/discharging approach for series-connected batteries. The proposed method uses switches to regulate the charging/discharging energy without any magnetic components. The balancing mechanism activated after a battery terminal voltage reaches the rated voltage and charging /discharging the battery with hysteresis charging/discharging...
A novel high efficiency PWM ZVS full-bridge dc-dc converter is presented. A half-bridge LLC resonant circuit which operates at a specific resonant frequency assists the PSFB dc-dc converter achieving ZVS of the lagging-leg switches from zero to full load. The output voltage of LLC resonant circuit is applied to the leakage inductance during the freewheeling phases. The primary circulating current...
This paper proposes a novel battery-balancing mechanism. By modular and decentralized design, this balance circuit can be easily expanded for higher-voltage battery strings. Bidirectional flyback converter is applied to transfer the energy from and back to the connected battery module. A capacitor is placed on the common paralleled secondary side to serve as an energy buffer. Average string voltage...
Passive power filters are necessary for attenuating the switching frequency harmonics introduced by the modulation of power converters. Recently, various topologies of novel passive power filters have been proposed to enhance their respective attenuation ability with relatively small filter components, i.e., filter inductors and capacitors. This paper reviews the state-of-the-art passive power filters...
As time progresses and technology develops in recent years, the demand for networking communication products is on the increase. Almost all nations throughout the world adopt AC power transmission system. To avoid current phase shift or distortion that would indirectly influence energy conversion performance and power quality in the AC-DC conversion process, it's important to insert PFC into power...
This paper presents the performance analysis of filter sensing board for extracting ac ripple information to estimate the battery impedance for the sinusoidal ripple current charging technique. The charging ac ripple content is extracted from the battery voltage and current by filtering the dc component using an op-amp filter circuit while producing a 90° phase angle in order to transform the a-p...
The output torque is the control objective of PMSM (Permanent Magnet Synchronous Motor) in urban rail train traction system. The commonly used torque control methods are affected by the variation of motor inductance parameters, which reduces the torque control precision. Based on mathematical model of PMSM extended flux, a minimum order state observer is established in this paper. Stator flux is got...
In order to precisely test the switching performance of high speed SiC MOSFET, this paper researches the test method. The simulation switching waveforms considering the parasitic inductors are compared to the switching waveforms without considering the parasitic inductors in this paper. The distinctions of comparative results are obvious and prove the effects of parasitic inductors on switching performance...
The various schemes of electric vehicle (EV) charging and the related impacts on electrical generation, transmission and distribution systems has been the subject of intense research over the past decade. The major problems have been narrowed down more to the distribution side of the electricity network. With this background, it becomes critical for a place like Singapore with heavy reliance on electricity...
With the rising concern of the current environmental issues, many renewable options of energy source are developing rapidly. We believe in the near future; these energy sources will be made affordable to everyone including the people in the developing countries. Solar technology is one of the renewable sources of energy which have made multiple breakthrough since its first debut in the 1960s. This...
Phase-shift transformers have been widely used for harmonic cancellation in a large-scale three-phase motor drive system. For a shipboard with multiple sources and loads, a shunt-connected phase-shift transformer can serve as harmonic path to conduct certain harmonic contents. This paper shows how the harmonics can be cancelled in a dual drivetrain system of a shipbboard. A laboratory scale of two...
Infrastructure Asset Management was first adopted in 1980s for challenges faced by the utilities, road and rail transport systems, mining, process and manufacturing industries in asset life cycle value optimization. International standards ISO 55000 and PAS 55 were subsequently developed to provide a basis for a structured methodology in the development of Asset Management System. This methodology...
This paper reviews four different AC/DC converter topologies, and implement them to compare with each other. These selected circuits are analyzed with component quantity, current stress, and converter efficiency performances where these four circuits are selected to support the universal input (90∼264 Vrms) and meet 1.3k Watt/400V DC output, 1 Watt/cm3 power density, and 12ms hold-up time. The density...
Most of the existing unbalanced control strategies only focus on a single control objective, which makes it difficult for three-phase grid-connected inverters to operate at an optimal performance according to the demand. This paper has analyzed the amplitude and phase relations between the positive- and negative-sequence output current under different control objectives, and then proposes a simplified...
Electric roads have had a pleasant journey through the research landscape but are now about to enter the “valley of death.” The basic technologies for dynamic power transfer from the road to vehicles in motion has been developed through various research projects across the globe, largely supported by public funding. Electric road systems (ERS) will soon be tested on public roads, but is still a long...
In this paper we present our project on interdisciplinary evaluations of existing smart grid environments regarding (1) the technical performance of smart energy products and services, (2) end users perceptions, (3) stakeholder processes and (4) market aspects. Our evaluations are based on data and information originating from real life pilots and demonstration projects in the field of smart grids...
In this paper, a novel multilevel electrolytic capacitor-less inverter is proposed. With the three-winding coupled inductor, input voltage can be divided without electrolytic capacitors. Hence, no voltage-balancing circuit is needed. Less power switches are required for the proposed circuit compared to the existing topologies. Only ten switches are required to generate seven-level output. Finally,...
In this manuscript, an optimized and detailed controller design methodology is proposed for a bidirectional CLLLC-type resonant converter for battery charging application. While this topology of resonant converters offers a number of advantages, including soft-switching in all switches, and very high power-stage efficiency, the dynamic characteristics of this converter change significantly as the...
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