Author
J.B. Vieira
Bio: J.B. Vieira is an academic researcher. The author has contributed to research in topics: Pulse-frequency modulation & Topology (electrical circuits). The author has an hindex of 1, co-authored 1 publications receiving 17 citations.
Papers
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06 Nov 1989
TL;DR: In this paper, a forward pulsewidth modulated zero-current switching quasi-resonant converter (F-PWM-ZCS-QRC) is proposed to provide output voltage and power control at a constant operating frequency.
Abstract: The authors propose a forward pulse-width modulated zero-current switching quasi-resonant converter (F-PWM-ZCS-QRC), which, in contrast to the conventional forward frequency-modulated zero-current switching quasi-resonant converter (F-FM-ZCS-QRC), provides output voltage and power control at a constant operating frequency. The topology is generated by inserting an additional current-bidirectional switch in the conventional F-FM-ZCS-QRC. The operation principle and design-oriented analysis are presented, with normalized design curves, design procedure, numerical examples, simulations, and experimental results. Theoretical analysis was verified experimentally with a prototype rated at 100 W, operating at the resonant frequency of 1.56 MHz and a switching frequency of 500 kHz. It has been experimentally demonstrated that the proposed converter operates from full load down to 2% of full load, with a constant switching frequency of 500 kHz. >
17 citations
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TL;DR: According to the simulation and experimental results, this quadratic boost converter provides a larger conversion ratio than that provided by the conventional boost converter (for a given duty ratio D), and presents optimum performance, which operates with soft-switch commutation using a single resonant network.
Abstract: This paper presents a quadratic boost converter using a single quasi-resonant network to reach soft commutation. A resonant inductor, a resonant capacitor, and an auxiliary switch form the resonant network and the main switch operates in a zero-current-switching way. A complete analysis of this converter is presented. According to the simulation and experimental results, this quadratic boost converter provides a larger conversion ratio than that provided by the conventional boost converter (for a given duty ratio D), and presents optimum performance, which operates with soft-switch commutation using a single resonant network.
104 citations
15 Feb 1998
TL;DR: In this paper, a boost converter with a nondissipative snubber is presented, which allows the main switch to operate in a ZVS way and the auxiliary switch to work in a CS way.
Abstract: This paper presents a boost converter with a nondissipative snubber which provides a soft switching converter operation. This approach allows the main switch to work in a ZVS way and the auxiliary switch to work in a ZCS way. The nondissipative snubber is composed by two capacitors (resonant capacitors), one inductor (resonant inductor), one switch (auxiliary switch) and two diodes, one in series with the main switch and the other in series with the auxiliary switch. The complete operating principle, relevant equations, simulation results and experimental results are presented.
25 citations
07 Aug 2002
TL;DR: In this article, the authors proposed an improvement of an isolated unity-power-factor rectifier AC/DC PWM based on a PWM full bridge converter using a commutation cell.
Abstract: This paper proposes an improvement of an isolated unity-power-factor rectifier AC/DC PWM based on a PWM full bridge converter using a commutation cell. This converter operates using soft switching technique. It presents high power factor, full control of the output dc voltage and high-frequency line filter inductor and insulation transformer. It is based in an auxiliary voltage source that feeds the resonant circuit, charging a capacitor that provides the condition for zero voltage switching (ZVS) of the main switches. This paper presents a detailed analysis of the topology, which is then verified by means of complete theoretical analysis, operating principles and simulation results are presented to show the feasibility of proposed power factor correction converter. This work presents simulations and experimental results of a prototype converter operating at 100 kHz.
18 citations
TL;DR: In this article, the authors reported the operation and development of a high power factor power supply that operates at high switching frequency using an ac-dc boost converter associated to a nondissipative snubber as a pre-regulator circuit, which presented reduced commutation losses.
Abstract: This work reports the operation and development of a high power factor power supply that operates at high switching frequency. An optimum power factor correction is obtained using an ac-dc boost converter associated to a nondissipative snubber as a pre-regulator circuit, which presents reduced commutation losses. The same nondissipative snubber is associated to a Forward converter and then used as a dc-dc stage. The proposed switched mode power supply presents high power factor (0.998), high efficiency (91%), low harmonic content (current and voltage total harmonic distortion rates equal to 2.84% and 2.83%, respectively), and also satisfactory regulation. The converter has been theoretically analyzed, designed, simulated and implemented, where experimental results show that soft commutation in all switches is achieved.
18 citations
15 Oct 2000
TL;DR: This paper presents a forward converter with a nondissipative snubber that allows the main switch toWork in a ZVS way and the auxiliary switch to work in aZCS way.
Abstract: This paper presents a forward converter with a nondissipative snubber. This approach allows the main switch to work in a ZVS way and the auxiliary switch to work in a ZCS way. Two capacitors, one inductor, one switch (auxiliary switch) and one diode in series with the main switch compose the nondissipative snubber.
8 citations