scispace - formally typeset
Search or ask a question
Author

Ching-Ming Lai

Bio: Ching-Ming Lai is an academic researcher from National Chung Hsing University. The author has contributed to research in topics: Ćuk converter & Flyback converter. The author has an hindex of 21, co-authored 108 publications receiving 1672 citations. Previous affiliations of Ching-Ming Lai include National Formosa University & National Tsing Hua University.


Papers
More filters
Journal ArticleDOI
TL;DR: A novel high step-up converter is proposed for fuel-cell system applications to achieve a much higher voltage conversion ratio and avoid operating at extreme duty ratio and to adopt lower voltage rating devices to further reduce both switching and conduction losses.
Abstract: In this paper, a novel high step-up converter is proposed for fuel-cell system applications. As an illustration, a two-phase version configuration is given for demonstration. First, an interleaved structure is adapted for reducing input and output ripples. Then, a C?uk-type converter is integrated to the first phase to achieve a much higher voltage conversion ratio and avoid operating at extreme duty ratio. In addition, additional capacitors are added as voltage dividers for the two phases for reducing the voltage stress of active switches and diodes, which enables one to adopt lower voltage rating devices to further reduce both switching and conduction losses. Furthermore, the corresponding model is also derived, and analysis of the steady-state characteristic is made to show the merits of the proposed converter. Finally, a 200-W rating prototype system is also constructed to verify the effectiveness of the proposed converter. It is seen that an efficiency of 93.3% can be achieved when the output power is 150-W and the output voltage is 200-V with 0.56 duty ratio.

207 citations

Journal ArticleDOI
TL;DR: In this paper, a modular interleaved boost converter is proposed by integrating a forward energy-delivering circuit with a voltage-doubler to achieve high step-up ratio and high efficiency for dc-microgrid applications.
Abstract: In this paper, a modular interleaved boost converter is first proposed by integrating a forward energy-delivering circuit with a voltage-doubler to achieve high step-up ratio and high efficiency for dc-microgrid applications. Then, steady-state analyses are made to show the merits of the proposed converter module. For closed-loop control design, the corresponding small-signal model is also derived. It is seen that, for higher power applications, more modules can be paralleled to increase the power rating and the dynamic performance. As an illustration, closed-loop control of a 450-W rating converter consisting of two paralleled modules with 24-V input and 200-V output is implemented for demonstration. Experimental results show that the modular high step-up boost converter can achieve an efficiency of 95.8% approximately.

189 citations

Journal ArticleDOI
TL;DR: In this article, a novel five-level multistring inverter topology for DERs-based dc/ac conversion system is proposed, where a high step-up converter is introduced as a front-end stage to improve the conversion efficiency of conventional boost converters and stabilize the output dc voltage of various DER-based modules for use with the simplified multilevel inverter.
Abstract: In the microgrid system, the distributed energy resource (DER)-based single-phase inverter is usually adopted. In order to reduce conversion losses, the key is to save costs and size by removing any kind of transformer as well as reducing the power devices. The objective of this letter is to study a novel five-level multistring inverter topology for DERs-based dc/ac conversion system. In this study, a high step-up converter is introduced as a front-end stage to improve the conversion efficiency of conventional boost converters and to stabilize the output dc voltage of various DERs such as photovoltaic and fuel cell modules for use with the simplified multilevel inverter. The simplified multilevel inverter requires only six active switches instead of the eight required in the conventional cascaded H-bridge multilevel inverter. In addition, two active switches are operated at the line frequency. The studied multistring inverter topology offers strong advantages such as improved output waveforms, smaller filter size, and lower electromagnetic interference and total harmonics distortion. Simulation and experimental results show the effectiveness of the proposed solution.

156 citations

Journal ArticleDOI
30 Aug 2018-Energies
TL;DR: This review paper is expected to provide a critical analysis of ESS developments, as well as recognize their research gaps in terms of reliability studies in modern RE-integrated power networks.
Abstract: Electricity plays a crucial role in the well-being of humans and is a determining factor of the economic development of a country. Electricity issues have encouraged researchers to focus on improving power availability and quality along with reliability. This pursuit has increasingly raised the intention to integrate renewable energy (RE) into power systems to curb the problem of energy deficiency. However, intermittency in the sources of RE supply coupled with fluctuating changes in demand with respect to time has induced high risk in maintaining system reliability in terms of providing adequate supply to consumers. Whilst an energy storage system (ESS) is not another source of electricity, it is proven to be effective and viable in solving the aforementioned issues. Thus, this paper comprehensively reviews the development of ESS technologies and discusses the benefits and real-life applications of these technologies. The concept of reliability in power systems is also explored to provide an improved understanding of this study. Lastly, notable studies that have addressed the reliability impact of ESSs on power systems are discussed. This review paper therefore is expected to provide a critical analysis of ESS developments, as well as recognize their research gaps in terms of reliability studies in modern RE-integrated power networks.

124 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present for the first time the reliability modelling of battery energy storage systems and dynamic thermal rating (DTR) systems for wind energy in power networks, and the results show that both systems can lower demand losses and increase the saved, supported and delivered wind energy depending on the settings of the two systems.

110 citations


Cited by
More filters
01 Sep 2010

2,148 citations

01 Jan 2016
TL;DR: This power electronics converters applications and design helps people to enjoy a good book with a cup of tea in the afternoon, instead they cope with some malicious virus inside their desktop computer.
Abstract: Thank you for downloading power electronics converters applications and design. Maybe you have knowledge that, people have look numerous times for their favorite readings like this power electronics converters applications and design, but end up in harmful downloads. Rather than enjoying a good book with a cup of tea in the afternoon, instead they cope with some malicious virus inside their desktop computer.

754 citations

Journal ArticleDOI
TL;DR: A proper comparison is established among the most important non-isolated boost-based dc-dc converters regarding the voltage stress across the semiconductor elements, number of components and static gain.
Abstract: The major consideration in dc-dc conversion is often associated with high efficiency, reduced stresses involving semiconductors, low cost, simplicity and robustness of the involved topologies. In the last few years, high-step-up non-isolated dc-dc converters have become quite popular because of its wide applicability, especially considering that dc-ac converters must be typically supplied with high dc voltages. The conventional non-isolated boost converter is the most popular topology for this purpose, although the conversion efficiency is limited at high duty cycle values. In order to overcome such limitation and improve the conversion ratio, derived topologies can be found in numerous publications as possible solutions for the aforementioned applications. Within this context, this work intends to classify and review some of the most important non-isolated boost-based dc-dc converters. While many structures exist, they can be basically classified as converters with and without wide conversion ratio. Some of the main advantages and drawbacks regarding the existing approaches are also discussed. Finally, a proper comparison is established among the most significant converters regarding the voltage stress across the semiconductor elements, number of components and static gain.

459 citations

Proceedings ArticleDOI
07 Jul 2011
TL;DR: In this article, the features of the established concepts for the high power range (M2C) and of new concepts for low power ranges (MHF) for modular multilevel converters are explained.
Abstract: Demanding future applications in power transmission and drives — like solar-thermic power plants and off-shore wind power — require advanced converter systems. Modular Multilevel Converters are well adopted to these needs, owing to industrial scalability, high efficiency and fast dynamic controllability under transient and fault conditions — including DC-Side faults. The respective features of the established concepts for the high power range (M2C) and of new concepts for the low power range (MHF) are explained.

385 citations

Journal ArticleDOI
TL;DR: In this article, the authors provide an introduction, review, and framework for the category of high-step-up coupled-inductor boost converters, which are categorized into five groups according to the major topological features.
Abstract: High-step-up, high-efficiency, and cost-effective dc–dc converters, serving as an interfacing cell to boost the low-voltage output of renewable sources to the utility voltage level, are an important part in renewable energy systems. Over the past few years, there has been a substantial amount of studies devoted to high-step-up dc–dc converters. Among them, the category of coupled-inductor boost converters is widely researched and considered to be a promising solution for high-step-up applications. In this paper, these converters are categorized into five groups according to the major topological features. The derivation process, advantages, and disadvantages of these converters are systematically discussed, compared, and scrutinized. This paper aims to provide an introduction, review, and framework for the category of high-step-up coupled-inductor boost converters. General structures for the topologies are proposed to clarify the topological derivation process and to show potential gaps. Furthermore, challenges or directions are presented in this paper for deriving new topologies in this field.

325 citations