• Journal of Power Electronics
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• v.16 no.5
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• pp.1689-1697
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• 2016

Continuous conduction mode (CCM) boost converters are commonly used in home appliances and various industries because of their simple topology and low input current ripples. However, these converters suffer from several disadvantages, such as hard switching of the active switch and reverse recovery problems of the output diode. These disadvantages increase voltage stresses across the switch and output diode and thus contribute to switching losses and electromagnetic interference. A new topology is presented in this work to improve the switching characteristics of CCM boost converters. Zero-current turn-on and zero-voltage turn-off are achieved for the active switches. The reverse-recovery current is reduced by soft turning-off the output diode. In addition, an input current sensorless control is applied to the proposed topology by pre-calculating the duty cycles of the active switches. Power factor correction is thus achieved with less effort than that required in the traditional method. Simulation and experimental results verify the soft-switching characteristics of the proposed topology and the effectiveness of the proposed input current sensorless control.

• Journal of Power Electronics
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• v.12 no.5
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• pp.689-698
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• 2012

This paper investigates the effects of applying different input current waveshapes on the performance of a continuous-conduction-mode (CCM) power-factor-correction (PFC) boost pre-regulator. It is found that the output voltage ripple of the pre-regulator can be reduced if the input current is modified to include controlled amount of higher order harmonics. This finding allows us to balance the performance of output regulation and the harmonic current emission when coming to the design of the pre-regulator. An experimental PFC boost pre-regulator prototype is constructed to verify the analysis and show the benefit of the pre-regulator operating with input current containing higher order harmonics.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.430-431
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• 2018

DC-DC 위상천이 풀브릿지 컨버터는 경부하 운용시에 영전압 스위칭이 발생하지 않아 큰 스위칭손실이 발생한다. 경부하에서 위상천이 풀브릿지 컨버터의 낮은 효율을 개선하기 위해 DCM (Discontinuous Conduction Mode) 동작을 이용한다. 본 논문은 경부하에서 위상천이 컨버터의 DCM과 CCM (Continuous Conduction Mode) 동작의 특성 및 도통 손실 절감을 위한 동기 정류기의 제어 방법을 이론적으로 분석하고, 시뮬레이션을 통해 검증하였다.

• Journal of Power Electronics
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• v.18 no.1
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• pp.11-22
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• 2018

This paper presents a single switch, high step-up, non-isolated dc-dc converter suitable for renewable energy applications. The proposed converter is composed of a coupled inductor, a passive clamp circuit, a switched capacitor and voltage lift circuits. The passive clamp recovers the leakage inductance energy of the coupled inductor and limits the voltage spike on the switch. The configuration of the passive clamp and switched capacitor circuit increases the voltage gain. A wide continuous conduction mode (CCM) operation range, a low turn ratio for the coupled inductor, low voltage stress on the switch, switch turn on under almost zero current switching (ZCS), low voltage stress on the diodes, leakage inductance energy recovery, high efficiency and a high voltage gain without a large duty cycle are the benefits of this converter. The steady state operation of the converter in the continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is discussed and analyzed. A 200W prototype converter with a 28V input and a 380V output voltage is implemented and tested to verify the theoretical analysis.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.319-320
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• 2013

본 논문에서는 PSR(Primary Side Regulator)에 적용 가능한 새로운 방식의 부하 전류 예측 알고리즘을 제안한다. 기존의 부하 전류 예측 방식은 DCM(Discontinuous Conduction Mode) 및 BCM(Boundary Conduction Mode) 동작만이 가능하다. 하지만 제안된 방식은 Power Balance Rule을 적용한 간단한 알고리즘을 통해 CCM(Continuous Conduction Mode) 동작에서도 정확한 부하 전류 예측이 가능하다. 따라서 높은 출력을 요구하는 어플리케이션에서 고효율 달성에 유리하고, CC(Constant Current) 제어가 우수하다. 제안 알고리즘의 우수성과 신뢰성 검증을 위하여 12W급 플라이백 컨버터의 시작품을 제작하였고, 이를 이용한 실험 결과를 바탕으로 타당성을 확인한다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.47-48
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• 2012

In generally, grid connected single-phase flyback inverter is operated as boundary or discontinuous conduction mode. However, the flyback inverter can be operated in continuous conduction mode (CCM) due to its operating conditions in spite of it is designed to operate under boundary or discontinuous conduction mode. This situation causes unintended distortion to output current. In this paper, a current shaping method on unfolding bridge to reduce the output current distortion.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1120-1122
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• 2002

Switching power supply are widely used in many industrial field. Power factor improvement and harmonic reduction technique is very important in switching power supply. The power factor correction (PFC) circuit using boost converter used in input of power source is studied in this paper. It is analyzed distortional situations and harmonics of input currents that presented at continuous conduction mode(CCM) of boost PFC circuit. It is done simulations of harmonics distribution according to load variation by using PSPICE and MATLAB. From the actual experiment of boost PFC circuit the validity of the analysis is confirmed.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.369-372
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• 2002

This paper presents a family of continuous conduction mode with constant-switching pulse width modulator controllers. Unified implementation of quasi steady state approach for various DC-DC converters topoiogies is illustrated. The property and control low for quasi-state approach will be discussed in this paper. The different procedures will be discussed in details with different results for five commonly used DC-DC converters. Both trailing and leading edge pulse width modulation are used. Leading edge modulation can some times lead to simpler control circuitry as will be demonstrated in some circuits. These controllers do not require the multiplier in the voltage feed back loop, error amplifier in the current loop and rectified line voltage sensor, which are needed by traditional control methods. Controller examples and design arc analyzed.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1030-1033
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• 2002

This paper, a new simple controller operates in continuous conduction mode (CCM) for Boost power factor collection converter is introduced. The duty ratios are obtained by comparisons of a sensed signal from inductor current and a negative ramp carrier waveform in each switching period. By using the proposed controller, input voltage sensing, error amplifier in the current feedback loop, and analog multiplier／divider are not required, then, the control circuit implementation is very simple. To verify the proposed controller, the circuit simulation for Boost power factor correction converter was applied. For the results, the input current waveform was shaped to be closely sinusoidal, implying low THD.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.920-921
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• 2008

This paper presents the efficiency analysis of CCM(Continuous Current Mode) boost converter. A thorough efficiency analysis of a boost converter taking into account the conduction losses, the diode power loss, the switching losses, the gate-drive loss and the capacitive switching loss, for both continuous conduction mode is presented.