Comments on “Unified Analysis of Switched-Capacitor Resonant Converters”

Ioinovici, A.; Chung, Henry Shu-Hung; Makowski, M.S.; Tse, Chi Kong

doi:10.1109/tie.2006.885454

Cited by 53 publications

(27 citation statements)

References 3 publications

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“…Because of the modular structure of the MMCCC circuit, the required resonant inductance is quite small for each module, thus making it feasible to be realized by parasitic inductance in the circuit. The switching frequency does not need to be pushed to tens of megahertz [96] to utilize the circuit stray inductance. It has been demonstrated that stray inductance is large enough to resonate at around 100 kHz.…”

Section: Ivc Zero Current Switching (Zcs)-mmcccmentioning

confidence: 99%

Recent advances in multilevel converter/inverter topologies and applications

Peng

Qian

Cao

2010

The 2010 International Power Electronics Conference - ECCE ASIA -

218

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Multilevel converters and inverters have become the enabling power conversion technology for high voltage high power applications in today's power systems and large motor drives. Although the neutral-point clamped (NPC, a 3-level) inverter was invented in 1979, the multilevel concept was not formally established until the early 1990s when the diode-clamped multilevel inverter, the capacitor-clamped (or flying capacitor) multilevel inverter, and the cascade multilevel inverter were proposed and fully studied. In this paper, we will first focus on the research advances in developing the cascade multilevel inverter topologies and their system configurations for power system applications from reviewing the traditional power conversion technology and the needs to eliminate zigzag transformers required in the traditional technology, to how to configure the cascade multilevel inverters to deal with unbalance and real-power (or active-power) flow. These research breakthroughs have made the cascade multilevel inverters a perfect topology for power system applications such as FACTS devices. For example, the cascade multilevel inverter based 75 Mvar and 50 Mvar STATCOMs have been reported. Since the mid of 1990s, many contributors have made great effort in developing more multilevel inverter topologies because all the three multilevel topologies have certain limitations and are not operable in some applications. Then, we will review the generalized multilevel inverter topology, its topological advances to other multilevel inverters/ converters, and their potential applications. This paper also provides insights to how multilevel inverter topologies are related to each other and their pros and cons in practical applications.Index Terms-capacitor clamped multilevel, cascaded multilevel, diode clamped multilevel, modular multilevel converter.

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Section: Ivc Zero Current Switching (Zcs)-mmcccmentioning

confidence: 99%

Recent advances in multilevel converter/inverter topologies and applications

Peng

Qian

Cao

2010

The 2010 International Power Electronics Conference - ECCE ASIA -

218

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“…Very low power handling and high EMI are consequences of this kind of operation [6], [7]. Resonant SCCs (RSCs) are SCC alternatives in which the switches current is controlled by placing a small inductor in series with the switching capacitors [6]- [13]. However, not only the converter voltage gain is not adjustable in RSCs [13], but also it varies against load changing [9].…”

Section: Introductionmentioning

confidence: 99%

“…Resonant SCCs (RSCs) are SCC alternatives in which the switches current is controlled by placing a small inductor in series with the switching capacitors [6]- [13]. However, not only the converter voltage gain is not adjustable in RSCs [13], but also it varies against load changing [9]. To provide a fractional voltage gain, many diodes and capacitors ought to be used, which result in an increase of the converter cost, volume and conduction losses [8], [9].…”

Section: Introductionmentioning

confidence: 99%

A novel resonant LLC soft-switching inverting-buck converter

Jabbari

Najafabadi

Shahgholian

et al. 2013

2013 10th International Conference on Electrical Engineering/Electronics, Computer, Telecommunications and Information Technolo

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a new soft-switching resonant inverting-buck converter with high efficiency is presented. The proposed converter steps down and inverts the input voltage. The zerocurrent-switching (ZCS) technique is employed to reduce switching losses and Electromagnetic Interferences (EMI). An LLC resonant network is utilized to provide soft-switching conditions for all semiconductor devices. Experimental results verify the integrity of the proposed converter operation and the presented theoretical analysis.

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“…The idea is based on the authors' earlier proposal of the so-called "switched-capacitor resonant converters" which achieve soft switching by inserting small inductors in series with the switching capacitors. The fundamental problems associated with the so-called "switched-capacitor resonant converters" has been discussed in a recent publication [2]. The most severe limitation is the inability to provide regulation against input voltage changes and transient load changes.…”

mentioning

confidence: 99%

“…Reference [1] however, has been devoted to the historical case of open-loop SC circuits where switching capacitors are fully charged in each intermediate step, thus providing no output regulation. The basic problem of losing voltage regulation in such historical SC converter circuits has been discussed in [2] in terms of partial and full charging of the switching capacitors. The key idea is that the capacitors should never be fully charged at the nominal duty cycle in order to allow the converter to "maneuver" over an adequate range of voltage ratio in case of line voltage changes and load transients.…”

mentioning

confidence: 99%

Comments on "Design and analysis of switched-capacitor-based step-up resonant Converters"

Ioinovici

Tse

Chung

2006

IEEE Trans. Circuits Syst. I

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Abstract-With reference to a recently published paper, the realization of line and load regulation in switched-capacitor-based converters is discussed. We point out that achieving zero-current switching at the expense of losing line and load regulation is not practically feasible.In [1], a way of realizing zero-current-switching (ZCS) in step-up switched-capacitor (SC) converters has been presented. The idea is based on the authors' earlier proposal of the so-called "switched-capacitor resonant converters" which achieve soft switching by inserting small inductors in series with the switching capacitors. The fundamental problems associated with the so-called "switched-capacitor resonant converters" has been discussed in a recent publication [2]. The most severe limitation is the inability to provide regulation against input voltage changes and transient load changes. In this comment, we wish to comment on the technical feasibility of the specific circuits reported in [1].First of all, it should be pointed out that voltage regulation is an important requirement for all kinds of power converters. The proposed circuits by [1] provide fixed voltage ratios. This implies that the output voltage will follow any change in the input voltage and that no satisfactory transient response can be guaranteed in case of load variation. The converter thus fails to meet the main requirement of any switching power supply, which is to provide a constant output voltage against line and load variations. Closed-loop control is mandatory for achieving satisfactory load transient responses as well as line regulation. Therefore, the basic argument presented in [1, Sect. 6] that their converters require no closed-loop control because they have fixed voltage ratios is clearly not correct.As should be widely known, prior developments of SC power supplies have already advanced to a point where full output voltage regulation has been achieved in a versatile manner A. Ioinovici is with the

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Comments on “Unified Analysis of Switched-Capacitor Resonant Converters”

Abstract: The realization of line and load regulation in switchedcapacitor (SC)-based converters is discussed. A duty-cycle control is based on partial charging of the capacitors in the circuit. The influence on the efficiency is pointed out. The use of inductors in SC-based converters is discussed.

Cited by 53 publications

References 3 publications

Recent advances in multilevel converter/inverter topologies and applications

Recent advances in multilevel converter/inverter topologies and applications

A novel resonant LLC soft-switching inverting-buck converter

Comments on "Design and analysis of switched-capacitor-based step-up resonant Converters"

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