• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1027-1029
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• 2002

In this paper, we present the circuit topology and control scheme of single-phase dc/ac inverter based on class E dc/dc converter for automotive application. The proposed inverter consists of class E series resonant inverter and class E low dv/dt PWM synchronous rectifier with bi-directional switch.

• 전력전자학회논문지
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• 제7권4호
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• pp.322-331
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• 2002

본 논문은 단상 반파 PWM 정류기와 3상 2-leg 인버터를 결합한 단상-삼상 컨버터 회로에서 전원전압의 센서를 제거하여 3상 유도전동기를 저가형으로 구동하는 방법을 제안하고자 한다. 전원전압의 센서를 제거하기 위해 전원 전류의 실측치와 제어기 내의 모델전류가 일치하도록 관측기를 구성하여 전원전압을 추정한다. 본 논문에서 제안한 기법을 사용할 경우 스위칭 소자와 센서 수를 줄이면서 직류전압 일정제어, 입력전류의 정현제어 및 단위 역률 제어가 가능하고 VVVF 교류전압을 얻을 수 있다는 장점이 있다. 3[Hp]의 3상 유도전동기의 V/f 구동에 적용한 실험결과로 제시된 알고리즘의 타당성을 검증한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.169-173
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• 2005

In this paper, a comparative study of modified phase-angle, extinction-angle, and pulse width modulation control techniques for the purpose of power factor improvement of single-phase AC-AC voltage regulators have been illustrated as applied to a single-phase ac voltage converter by an example of the widely used single-phase induction motor as a dynamic load. Observations on power factor, displacement factor and total harmonic distortion factor are described and discussed on the basis of the simulated and measured results of this work.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2668-2670
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• 1999

In the past, the PWM converter had a large switching loss by hard switching and difficult to high frequency operation. The resonance converter to decrease the switching loss and EMI is required the frequency control and needed to reduce the voltage or current stress at each parts. So, this paper propose the 3-phase boost converter and the method to compensated input power factor by control the amplitude - an instantaneous value of the DC inductor current -and control the switching frequency that a modulation error by the ripple of the DC inductor current. The proposed 3-phase PWM boost converter of single phase control type can takes higher capacity and compensate the power factor by using Feed back controller at each phase for the existing 3-phase bridge rectifier type. Moreover the 3-phase full bridge type using the rectifier at each 3-phase circuit will be small size reactor and compensate input power factor by minimize harmonic components of each phase.

• Journal of Power Electronics
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• 제15권2호
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• pp.356-365
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• 2015

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.

• 전기학회논문지P
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• 제61권3호
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• pp.122-128
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• 2012

An interleaved boost converter has many advantages such as current ripple reduction, switching effective double, etc. Due to these advantages, the interleaved boost converter applies to the power factor correction circuit. However, there are almost no analysis results because the input voltage and current are time-varying system in the power factor correction application. Therefore, in this paper, the current ripples of the power factor correction circuit using single-phase boost dc-dc converter and 2-phase interleaved boost dc-dc converter are compared and analyzed in detail. In order to verify the validity, computer simulation and experimental are performed.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1495-1502
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• 2017

The Theory of operation of switched reluctance motors (SRM) depends on the reluctance torque, where energy is transferred to stator winding only. Although its construction is simple, the electrical design is complex, due to the switching configuration needed to deliver power to stator coils. However, because of the nonlinearly of magnetic circuit, SRM has torque ripple. This paper proposes a new strategy to drive SRM from a single-phase AC supply. Each stator winding is connected to AC-DC or AC-AC converters, which is called branch. All branches are connected in parallel to a single-phase AC supply. A shaft encoder allows current production in stator winding during the positive torque production region and terminates it during the negative torque production region. A magnetic flux is produced between stator poles when current is supplied from AC supply to stator coil and repeats many cycles as long as the rate of change of stator inductance is positive. Different possibilities for the configurations of AC-AC or AC-DC converters are introduced to drive SRM from the single-phase AC supply. A case study is presented for a SRM fed from AC supply through semi-controlled AC-DC converter is presented. A simulation model is introduced and verified by experimental rig for two-phase SRM.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권8호
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• pp.529-535
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• 2000

In this paper, a current control system of a single phase PWM AC/DC converter using a reduced-order Luenberger observer without source voltage sensors is proposed. The sinusoidal input current and unity input power factor are realised based on the estimated source voltage performed by the reduced-order Luenberger observer using actual currents and DC link voltage. The poles of the reduced-order Luenberger observer are placed in the left half plane of s-plane by the pole-placement method in order to acquire the stability of the observer. The magnitude and the phase of the estimated source voltage are used to accomplish the unity power factor. The proposed method is implemented by DSP(Digital Signal Processor). Experimental Results verify that the reduced-order observer estimates the source voltage without the estimation error and the control system accomplishes the unity power factor, and constant DC link voltage.

• 조명전기설비학회논문지
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• 제18권5호
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• pp.61-68
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• 2004

최근, 연료전지는 새로운 발전시스템으로 주목받고 있다. 연료전지는 저전압/대전류의 전기적 특성을 가진다. 그러므로 일반 상용부하에 적용하기 위해서는 승압용 컨버터와 인버터가 필요하다. 제안된 시스템은 연료전지의 전압을 380[Vdc]로 승압하기 위한 절연형 DC-DC 컨버터와 단상 220[Vac]로 변환하기 위한 LC 필터를 가진 PWM 인버터로 구성된다. 또한, 연료전지 발전시스템용 양방향 DC-DC 컨버터는 부하 응답 특성을 개선시키기 위하여 구성하였다. 본 논문에서는 풀 브리지 컨버터와 단상 인버터를 설계하고 제작하였으며, 시뮬레이션과 실험을 통해 연료전지 발전 시스템이 분산전원에 적용이 가능함을 보여준다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.163-167
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• 2000

This paper presents the digital control of single-phase power factor correction(PFC) converter which has the variable gain according to the condition of inner control loop error. Generally the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This has a bad influence on the power factor because current loop doesn't operate smoothly in the condition that input voltage is low In particular a digital controller has more time delay than an analog controller and degrades This drops the phase margin of the total digital PFC system,. It causes the problem that the gain of current control loop isn't increased enough. In addition the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult The digital PFC controller presented in this paper has a variable gain of current control loop according to input voltage. The 1kW converter was used to verify the efficiency of the digital PFC controller.