• Journal of Power Electronics
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• 제14권2호
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• pp.249-256
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• 2014

A novel topology generation method for the no dead-time three-phase AC/DC converter is proposed in this study. With this method, a series of no dead time topologies are generated and their operation principles are analyzed. The classic three-phase bridge AC/DC converter can realize a bidirectional operation. However, dead-time should be inserted in the driving signals to avoid the shoot-through problem, which would cause additional harmonics. Compared with the bridge topology, the proposed topologies lack the shoot-through problem. Thus, dead time can be avoided. All of the no dead time three-phase AC/DC converters can realize bidirectional operation. The operating principles of the converters are analyzed in detail, and the corresponding control strategies are discussed. Comparisons of waveform distortion and efficiency among the converters are provided. Finally, 9 KW DSP-based principle prototypes are established and tested. Simulation and experimental results verify the theoretical analysis.

• Journal of Power Electronics
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• 제18권2호
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• pp.407-417
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• 2018

A novel family of Buck mode three-level direct ac converters with a high frequency link is proposed. These converters can transfer an unsteady high ac voltage with distortion into a regulated sinusoidal voltage with a low THD at the same frequency. The circuit configuration is constituted of a three-level converter, high frequency transformer, cycloconverter, as well as input and output filters. The topological family includes forward, push-pull, half-bridge, and full-bridge modes. In order to achieve a reliable three-level ac-ac conversion, and to overcome the surge voltage and surge current of the cycloconverter, a phase-shifted control strategy is introduced in this paper. A prototype is presented with experimental results to demonstrate that the proposed converters have five advantages including high frequency electrical isolation, lower voltage stress of the power switches, bi-directional power flow, low THD of the output voltage, and a higher input power factor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.435-436
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• 2016

본 논문에서는 3상 Quasi Z-소스 AC/AC 전력변환기를 제안한다. 제안된 전력변환기는 3대의 단상 Quasi Z-소스 AC/AC 컨버터로 구성되어 있으며, 간단한 듀티 비 제어만으로도 동상 및 역상의 벅-부스트 출력 전압의 발생이 가능하다. 제안된 방식은 PSIM 시뮬레이션을 통하여 타당성을 확인하였다.

• 전력전자학회논문지
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• 제26권6호
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• pp.446-453
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• 2021

This paper proposes enhanced single-phase pulse width modulation buck, boost, and buck-boost type ac-ac converters. The proposed converters, where input and output voltages share a common ground, require no isolated voltage sensor and have no leakage current problem. The commutation problem is solved with series-connected switching cell structures without using an additional RC snubber. In addition, with the use of the polarity of input voltage, switching patterns are determined so that the inductor currents can flow through switching devices during all operational modes. Two switches are always turned on during a half-period of the input voltage; thus, the switching loss is significantly reduced. Detailed analysis and experimental results are provided to verify the performance of the proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.362-365
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• 1999

In this paper, the method of reducing harmonics and correcting of power factor in single PWM converter associated with diode rectifier and boos converter is studied. The ac-dc converter in which the harmonic distortion in the input current is reduced using a third harmonic injected PWM is proposed. A lower switching power loss and easy configuration o control circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[KHz] switching frequency are presented and correction of power factor and reduction of total harmonic distortion was established.

• Journal of Power Electronics
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• 제9권1호
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• pp.124-131
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• 2009

This paper presents a PWM dc-ac converter regulation using a Single Input Fuzzy PI Controller (SIFPIC). The SIFPIC is derived from the signed distanced method, which is a simplification of a conventional fuzzy controller. The simplification results in a one-dimensional rule table, that allows its control surface to be approximated by a piecewise linear relationship. The controller multi-loop structure is comprised of an outer voltage and an inner current feedback loop. To verify the performance of the SIFPIC, a low power PWM dc-ac converter prototype is constructed and the proposed control algorithm is implemented. The experimental results show that the SIFPIC performance is comparable to a conventional Fuzzy PI controller, but with a much reduced computation time.

• 전력전자학회논문지
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• 제15권4호
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• pp.259-265
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• 2010

본 논문에서는 더 높은 에너지 효율을 요구하는 전자 기기들의 사용에 따른 고전력 밀도 AC/DC 어댑터의 구조를 제안한다. PFC (Power Factor Corrector) topology는 BCM (Boundary Conduction Mode)제어 방식을 적용한 Boost topology를 기본으로 하였으며, DC/DC topology는 주파수제어를 적용한 LLC 공진 컨버터를기본으로 하였다. 이는 반도체 소자 및 마그네틱 소자의 크기를 줄이는데 용이하다. 85W급 AC/DC adapter (18.5V/4.6A)를 설계하여 실험한 결과 $90V_{rms}$의 입력전압에서 90%의 효율과 $36W/in^3$의 전력밀도가 측정되었고 무부하시 전력 손실은 0.5W를 달성하였다.

• Journal of Power Electronics
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• 제16권5호
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• pp.1894-1903
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• 2016

In general, electrolytic capacitors are used to reduce power pulsations on PV-panels. However, this can reduce the reliability of the PV AC-module system, because electrolytic capacitors have a shorter lifetime than PV-panels. In addition, PV-panels generate irregular power and inject it into the grid because the output power of a PV-panel depends on the surrounding conditions such as irradiation and temperature. To solve these problems, a grid-connected photovoltaic (PV) AC-module with active power decoupling and energy storage is proposed. A parallel bi-directional converter is connected to the AC module to reduce the output power pulsations of PV-panels. Thus, the electrolytic capacitor can be replaced with a film capacitor. In addition, the irregular output power due to the surrounding conditions can be regulated by using a parallel energy storage circuit. To maintain the discontinuous conduction mode at low irradiation, the frequency control method is adopted. The design method of the proposed converter and the operation principles are introduced. An experimental prototype rated at 125W was built to verify the performance of the proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.266-269
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• 2000

This paper presents a novel single-stage unity power factor converter which features the reduced switching losses by zero-voltage switching and zero-current switching (ZVZCS). Hence the turn-on and turn-off losses of switches are sufficiently reduced. And the reduced conduction losses are achieved by the elimination of one leg of front-end rectifier. And low on-resistance MOSFETs (Synchronous Rectifier) are used in the rectifier at the secondary side of high frequency transformer instead of diodes. Theoretical analysis simulated results of a AC to DC 150W(5V, 30A) converter are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.282-285
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• 2000

A new current controller implemented in a-b-c frame for AC-DC converter is proposed. The proposed MTPWM(Modified Trapezoidal PWM) Which is quite suitable for three phase AC-DC converter. It is known that MTPWM has good harmonics characteristics for high modulation index. It is very simple and requires no transformation in it. The results of computer simulation are shown for the validity of proosal.