• 한국전자통신학회논문지
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• 제10권3호
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• pp.365-373
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• 2015

기존 6스위치 3상 인버터(SSTPI)의 한 상을 스위치 대신 커패시터로 대체한 4스위치 3상 인버터(FSTPI)에서 양 커패시터 전압의 불평형에 의한 출력전압의 오차를 보상하는 것은 FSTPI의 성능을 결정하는 중요한 요소이다. 본 논문에서는 DC 오프셋 전류 주입에 의하여 FSTPI의 커패시터 전압 불평형을 보상하는 새로운 방법과 FSTPI에 적용할 수 있는 간략화된 SVPWM 방법을 제안한다. 제안된 방법은 컴퓨터 시뮬레이션을 통해 타당성을 검증하였다.

• 한국전자통신학회논문지
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• 제11권3호
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• pp.283-292
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• 2016

6스위치 3상 인버터(SSTPI)의 한 상을 스위치 대신 커패시터로 대체한 4스위치 3상 인버터(FSTPI)에서 커패시터 전압의 불평형으로 인한 출력 전압의 오차를 보상하는 방법과 전압 제어 방법은 FSTPI의 성능을 결정짓는 중요한 요소이다. 본 논문에서는 DC 오프셋 전류 주입 통한 FSTPI의 커패시터 전압의 불평형을 보상하는 새로운 방법과 FSTPI의 새로운 전압 제어 방법인 간략화 된 SVPWM을 제안한다. 제안된 방법은 FSTPI로 SPMSM를 구동하는 시뮬레이션과 실험을 통해 그 타당성을 검증하였다.

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.290-298
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• 2010

This paper proposes an adaptive carrier-based pulse width modulation (PWM) method for a four-switch three-phase (4S3P) inverter under dc-link voltage ripple conditions. The proposed method guarantees balanced output currents despite of the existence of the voltage oscillations across two dc-link capacitors. And also, this new approach achieves a linear over-modulation with calculation time reduction. Simulation and experimental results are given to validate the feasibility of the proposed method.

• 전기학회논문지P
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• 제58권4호
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• pp.391-396
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• 2009

In this paper, a control algorithm for DC-Link voltage unbalancing compensation of a four-switch inverter for a three-phase BLDC motor drive is proposed. Compared with a conventional six-switch inverter, the split source of the four-switch inverter can be obtained by splitting DC-link capacitor into two capacitors to drive the three phase BLDC motor. The voltages across each of two capacitors are not always equal in steady state because of the unbalance in the impedance of the DC-link capacitors $C_1$ and $C_2$ or the variable current flowed into the capacitor's neutral point in motor control. Despite the unbalance, if the BLDC motor may be run for a long time the voltage across one of the capacitors is more increased. So the unbalance in the capacitors voltages will be accelerated. As a result, The current ripple and torque ripple is increased due to the fluctuation of input current which flows into 3-phase BLDC motor. According to that, the vibration of motor will be increased and the whole system will be instable. This paper presents a control algorithm for DC-Link voltage unbalancing compensation. The sampling from the voltages across each of two capacitors is used to perform the voltage control of DC-Link by using the feedforward controller.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1471-1483
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• 2017

The low-frequency characteristics of four-switch three-phase (FSTP) inverter are investigated in this paper. Firstly, a general space vector pulse width modulation (SVPWM) directly involved the neutral point voltage of DC-link is proposed, where no sector identifications and trigonometric function calculations are needed. Subsequently, to suppress the DC offset in the neutral point voltage, the relationship between the neutral point voltage and the ${\beta}-axis$ component of the load current is derived, and then a new neutral point voltage control scheme is proposed where no low pass filter is adopted. Finally, the relationship between the load power factor and the maximum linear modulation index of the FSTP inverter is revealed. Since the operational region for the FSTP inverter in low frequency is reduced by the enlarged amplitude of the neutral point voltage, a linear modulation range enlargement scheme is proposed. A permanent magnet synchronous motor with preset rotary speed serves as the low-frequency load of the FSTP inverter. Experimental results verify that the new neutral point voltage control scheme is effective in the deviation suppression of the neutral point voltage, and the proposed scheme is able to provide a larger linear operational region in low frequency.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1015-1024
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• 2015

This paper introduces a low cost, high efficiency, high performance three-phase unified power quality conditioner (UPQC) by using four-switch three-phase inverters (FSTPIs) and an extra capacitor in the shunt active power filter (APF) side of the UPQC. In the proposed UPQC, both shunt and series APFs are developed by using FSTPIs so that the number of switching devices is reduced from twelve to eight devices. In addition, by inserting an additional capacitor in series with the shunt APF, the DC-link voltage in the proposed UPQC can also be greatly reduced. As a result, the system cost and power loss of the proposed UPQC is significantly minimized thanks to the use of a smaller number of power switches with a lower rating voltage without degrading the compensation performance of the UPQC. Design of passive components for the proposed UPQC to achieve a good performance is presented in detail. In addition, comparisons on power loss, overall system efficiency, compensation performance between the proposed UPQC and the traditional one are also determined in this paper. Simulation and experimental studies are performed to verify the validity of the proposed topology.

• Journal of Power Electronics
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• 제7권2호
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• pp.109-117
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• 2007

In this paper, a novel proposal for a utility-interactive three-phase soft commutation sinewave PWM power conditioner with an auxiliary active resonant DC-link snubber is developed for fuel cell and solar power generation systems. The prototype of this power conditioner consists of a PWM boost chopper cascaded three-phase power conditioner, a single two-switch auxiliary resonant DC-link snubber with two electrolytic capacitors incorporated into one leg of a three-phase V-connection inverter and a three-phase AC power source. The proposed cost-effective utility-interactive power conditioner implements a unique design and control system with a high-frequency soft switching sinewave PWM scheme for all system switches. The operating performance of the 10 kW experimental setup including waveform quality, EMI/RFI noises and actual efficiency characteristics of the proposed power conditioner are demonstrated on the basis of the measured data.

• 전력전자학회논문지
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• 제9권5호
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• pp.430-437
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• 2004

본 논문에서는 고주파 스위칭 시 스위칭 손실의 감소, 구현의 용이성 및 인버터 제어를 위하여 요구되는 연산시간 감소 등 다양한 장점을 가진 4-Switch 인버터를 대상으로, 새로운 2상 스위칭 패턴(Pattern)과 이에 적용된 새로운 SRP-PWM(Separately Random Pulse Position PWM)기법을 제안한다. 본 논문에서는 고속운전 영역에서의 인버터 출력전류의 고조파 스펙트럼을 넓은 주파수 영역으로 즉, 특정주파수의 side-band로 고루 분산시키는 결과로부터 제안한 스위칭 패턴과 이에 적용된 새로운 SRP-PWM기법의 고조파 저감효과를 확인하고자 한다. 따라서 DSP를 이용한 IGBT인버터에 의한 실험을 수행하고, 이로부터 얻은 결과를 MATLAB/SIMULINK를 이용한 시뮬레이션 결과와 비교ㆍ분석하여 제안된 기법의 타당성을 검증하고자 한다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.100-109
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• 2017

This paper proposes performance improvement schemes for sensorless PMSM control drive using a four-switch three-phase inverter (so-called B4 inverter). In the proposed scheme, the back-EMF estimation-based sensorless control algorithm is used to control the brushless PMSM without position sensors. In order to have stable operation, this paper presents a gain adjustment scheme that compensates the reduction of stable sensorless operation range as long as the rotor speed increases. In B4 topology, the center point of dc-link capacitors is connected to 3-phase load, and it is prone to have the load current distortion. Hence, to mitigate this problem, a distortion compensation scheme by modifying voltage commands using measured dc-link potentials is proposed in this paper. The validity of the proposed method is evaluated by simulations and experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.641-645
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• 2004

This paper presents a new speed control method using the acceleration feedforward compensation and using the disturbance torque estimate method. The proposed method improve transition response characteristic of system and has been a robust characteristic in the four-switch three-phase motor drive system in which the gain of speed controller cannot be made large enough. The simulation results prove the validity of the proposed method.