• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.108-113
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• 2021

In this paper, a totem pole PFC was structured in two methods with FET and diode for low-speed switch while GaN FET was used for high-speed switch. Internal power loss, power conversion efficiency and steady-state characteristics of the two methods were compared in the totem pole bridgeless PFC circuit which is widely applied in large-capacity and high-efficiency switching rectifier of 500W or more. In order to compare and confirm the steady-state characteristics under equal conditions, a 2kW class totem pole bridgeless PFC was constructed and the experimental results were analyzed. From the experimental results, it was confirmed that the low-speed switch operation has a large difference in efficiency due to the internal conduction loss of the low-speed switch at a low input voltage. Especially, input power factor and load characteristic showed no difference regardless of the low-speed switch operation.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.22-27
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• 2020

In this paper, a generalized efficiency equation was proposed to estimate the internal loss of the SMPS (switched-mode power supply) with 3 variables. The first variable was an internal loss not related to the load current such as auxiliary power, the second was a loss proportional to the current such as diode loss, and the third was a loss proportional to square of the current such as conduction loss. Especially, theoretical internal losses of the totem pole bridgeless PFC which is widely used for high efficiency SMPS were expressed as output function to compare generalized efficiency equation. In addition, in order to reduce the conduction loss of the switch, when a multiple switch were paralleled, the correlation with the efficiency was analyzed and shown as a graph. In order to confirm the degree of the parallel switch structure on the efficiency improvement, a 2kW class totem pole bridgeless PFC was constructed and the effectiveness of the analysis was confirmed by comparing the generalized efficiency equation and theoretical loss analysis results with experimental data.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.214-222
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• 2015

The superiority of gallium nitride FET (GaN FET) over silicon MOSFET is examined in this paper. One of the outstanding features of GaN FET is low reverse-recovery charge, which enables continuous conduction mode operation of totem-pole bridgeless boost power factor correction (PFC) circuit. Among many bridgeless topologies, totem-pole bridgeless shows high efficiency and low conducted electromagnetic interference performance, with low cost and simple control scheme. The operation principle, control scheme, and circuit implementation of the proposed topology are provided. The converter is driven in two-module interleaved topology to operate at a power level of 5.5 kW, whereas phase-shedding control is adopted for light load efficiency improvement. Negative bias circuit is used in gate drivers to avoid the shoot-through induced by high speed switching. The superiority of GaN FET is verified by constructing a 5.5 kW prototype of two-module interleaved totem-pole bridgeless boost PFC converter. The experiment results show the highest efficiency of 98.7% at 1.6 kW load and an efficiency of 97.7% at the rated load.

• Journal of Power Electronics
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• v.19 no.1
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• pp.278-287
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• 2019

In this study, a zero-crossing spike current issue in a totem-pole bridgeless power factor correction (PFC) converter is comprehensively investigated for the first time. Spike current occurs when input voltage crosses zero, becomes a noise source, and causes severe common mode emission issues. A generation mechanism for electromagnetic interference (EMI) is presented to investigate the EMI problem caused by zero-crossing issue, and a noise spectrum due to this issue is predicted by a theoretical analysis based on the Fourier coefficient of an approximate spike current waveform. Furthermore, a noise reduction method is proposed and then improved to reduce the spike current. Experimental measurements are implemented on a GaN-based totem-pole bridgeless PFC converter, and the spike current can be effectively suppressed through the proposed method. Furthermore, the noise spectrums measured without and with the reduced zero-crossing spike current are compared. Experimental results validate the analysis of the noise spectrum caused by the zero-crossing spike current issue.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.151-152
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• 2012

본 논문은 전기자동차의 탑재형 충전기 (OBC, On-Board Charger)에 적용 가능한 고효율 역률개선회로 (PFC, Power Factor Correction Circuit)들의 손실을 분석한다. 평균전류모드제어를 이용하여 conventional boost PFC, interleaved boost PFC, semi-bridgeless PFC, totem pole PFC, seudo totem pole PFC, back-to-back bridgeless PFC, interleaved bridgeless PFC 등 7개의 토폴로지를 3.3kW OBC 기반으로 설계하고, 각 토폴로지의 손실을 수식과 PSIM의 thermal module을 이용하여 분석한다. 분석한 결과를 토대로 제시한 토폴로지들의 효율 및 성능을 비교한다.

• KIPE Magazine
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• v.26 no.6
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• pp.28-31
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• 2021

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.78-79
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• 2017

본 논문에서는 스위칭 손실을 저감한 고주파 인터리브드 토템폴 브리지리스 부스트 PFC 컨버터를 제안한다. 인터리브드 토템폴 브리지리스 부스트 PFC 컨버터는 하드 스위칭 동작을 하기 때문에 큰 스위칭 손실을 가지며, 고주파에서의 동작이 제한된다. 제안하는 컨버터는 수동 소자인 인덕터가 추가된 구조이며, 추가 인덕터의 에너지를 이용해 영전압 스위칭을 할 수 있다. 그 결과, 스위칭 손실이 저감되고 고주파 동작이 가능해진다. 또한 기존에 설계된 회로와 제어단을 그대로 유지할 수 있다.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.185-186
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• 2014

본 논문에서는 Si MOSFET 대비 GaN FET의 특성을 비교 분석하고, GaN FET의 장점을 활용할 수 있는 방안을 모색하였다. 그 결과 GaN FET의 우수한 reverse recovery 특성을 활용할 수 있는 토템폴 구조의 브리지리스 부스트 PFC 컨버터를 선정하였고, 선정한 회로의 동작 및 효율을 5.5kW급 프로토타입을 통하여 확인하였다.