• Journal of Power Electronics
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• v.15 no.6
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• pp.1547-1558
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• 2015

A predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) servo systems is proposed in this paper. The PFC-based method is first introduced in the control design of speed loop. Since the accuracy of the PFC model is influenced by external disturbances and speed detection quantization errors of the low distinguishability optical encoder in servo systems, it is noted that the standard PFC method does not achieve satisfactory results in the presence of strong disturbances. This paper adopted the Kalman filter to observe the load torque, the rotor position and the rotor angular velocity under the condition of a limited precision encoder. The observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC method, called the PFC+Kalman filter method, is presented, and a high performance PMSM servo system was achieved. The validity of the proposed controller was tested via experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

• Journal of Power Electronics
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• v.15 no.1
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• pp.78-85
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• 2015

This paper presents a new structure of single-stage flyback power factor correction (PFC) converter with a controllable coupled negative magnetic feedback (NMF) winding. NMF winding is used to reduce the bulk capacitor voltage at high line voltages and light loads. However, it would cause line current distortion at zero crossing condition. In the proposed circuit, a series winding is used with NMF inductor to eliminate the NMF inductor at low line voltages. As a result, the dead angle of the input current, near zero voltage crossing, is eliminated and the power factor is increased. The presented experimental results of the proposed PFC converter confirm the integrity of the new idea and the theoretical analysis.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.152-155
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• 2009

In high power application, PFC(Power Factor Correction) pre-regulators are generally required. PFC pre-regulators could achieve unity power factor, reduce line input current harmonics and utilize full line power. Interleaving PFC converters could reduce input ripple current, output capacitor ripple current and inductor size. With this closed loop interleaving method, both two phase converters are working at the boundary between continuous and discontinuous mode and accurate 180 degree phase shift is achieved. Implementation of this strategy could be easily integrated to the control chip. Finally, experimental results of a two-phase interleaved boost PFC are presented to verify the discussed features.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.465-471
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• 2007

The system efficiency of the proposed Buck-Boost AC-DC converter is increased by soft switching method. The converter includes to merit of power factor correction (PFC) from sinusoidal control of input current. The switching behavior of control switches operates with soft switching by partial resonance, and then the proposed converter has high system efficiency with decrement of switching power loss. The input current waveform in proposed converter is got to be a sinusoidal form of discontinuous quasi-pulse row in proportion to magnitude of AC input voltage under the constant duty cycle switching. Therefore, the input power factor is nearly unity. The output voltage of the converter is regulated by PWM control technique. The discontinuous mode action of current flowing into inductor makes to simplify control method and control components. The proposed PFC Buck-Boost converter is analyzed to compare with the conventional PFC Buck-Boost converter. Some computer simulative results and experimental results confirm to the validity of the analytical results.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.130-132
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• 2007

Recently, regulation for THD(Total Harmonic Distortion) such as IEC 61000-3-2, IEEE 519 is being reinforced about a product which directly connects to AC line in order to prevent distortion of common power source in electronic equipment and electrical machinery. In order to satisfy these regulations, conventional circuits were used two-stage structure attached power factor correction circuit at ahead of converter but this method complicate the circuit and then a number of element increases thereupon the cost of production rises. In this paper, we propose a high efficiency single-stage 300W PFC flyback converter, that improved power factor and efficiency than conventional two-stage power module.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.987-990
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• 2003

산업현장에서의 인터넷환경 및 원격 제어를 위한 시스템 개발에서 신뢰성이 있고 경제적이며 지능적인 Power Supply가 요구되고 있다. 최근 통신시스템의 Power Supply는 수 kA이상의 출력전류를 가지고 있으며 최소 10개 이상의 모듈로 이루어져 있다. High-End 서버 시스템과 같이 수백 개의 마이크로프로세서를 내장한 시스템은 수십 kW의 전력을 소모한다. 이들이 사용하는 Power Supply는 별도의 시스템 제어기와의 통신으로 시스템에서 발생하는 발열, 소모전력, Total Harmonic Distortion (THD)에 대한 정보를 바탕으로 시스템이 갖는 각각의 Module에 대해 효과적이고 신뢰성 있는 전력공급을 하여야 만다. Distributed Power System (DPS)에서 가장 중요만 역할을 담당하는 Power Factor Correction (PFC) AC-DC Converter의 디지털 제어는 시스템 제어기와의 통신능력을 충분히 고려하면서 DPS를 위한 적합한 솔루션을 제공할 것이다. 본 논문에서는 Digital Signal Processor (DSP)를 사용하여 PFC 제어에 필요한 전파정류전압, 입력전류, 출력전압을 계측하여 역률개선과 THD의 저감을 위한 전류의 추종을 제어하면서 이들 제어기에서의 파라미터를 PC를 통해 모니터하여 최근의 추세를 만족시킬 수 있는 시스템을 구현할 수 있을 것으로 사료된다.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.89-90
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• 2014

Recently, one of the switching rectifiers, Power Factor Correction Circuit is often applied in rectification stage to get high efficient conversion of AC-DC SMPS However, it becomes important to select optimal semiconductor switch as well as to design optimal rectifier for achieving higher power conversion. We performed experiments with MOSFET, SiC and GaN FET that are widely used in 600 W Interleaved CRM PFC and include the data in this report. The results are presented for discrete semiconductor and integrated implementations of interleaved CRM PFC.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• Journal of Power Electronics
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• v.15 no.3
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• pp.695-701
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• 2015

Uninterruptible Power Supplies (UPSs) can be largely divided into the passive-standby, line-interactive and double-conversion methods. This paper proposes a double-conversion UPS with a low cost and high performance. This single phase UPS uses a single-loop robust voltage controller and 1-switch voltage doubler strategy PFC. The proposed UPS is composed of a single phase PFC, a half-bridge inverter, a battery charger and a battery discharger. Finally, the validity of proposed UPS was verified by various experimental tests.

• Journal of Power Electronics
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• v.17 no.1
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• pp.31-40
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• 2017

A novel voltage-fed single-stage power factor correction (PFC) full-bridge converter based on asymmetric phase-shifted control for battery chargers is proposed in this paper. The attractive feature of the proposed converter is that it can operate in a wide output voltage range without an output low-frequency ripple, which is indispensable in battery charger applications. Meanwhile, the converter can maintain a high power factor and a controllable dc bus voltage over a wide output voltage range. In this paper, the realization of PFC and the operation principle of asymmetric phase-shifted control are given. A small-signal analysis of the proposed single-stage power factor correction (PFC) full-bridge converter is performed. Experimental results obtained from a 1kW experimental prototype are given to validate the feasibility of the proposed converter. The PF is higher than 0.97 over the entire output voltage range with the proposed control strategy.