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연료전지 전원을 갖는 Z-소스 능동전력필터에 의한 장거리 배전선로의 전압 THD 저감
鄭榮國(Young-Gook Jung) 대한전기학회 2008 전기학회논문지 Vol.57 No.12
This paper deals with a Z-source active power filter(Z-AFU) for mitigation voltage THD(total harmonic distortion) due to voltage harmonic propagation (amplification) in 6.6kv power distribution system. Bus voltage harmonic signal is detected by 60Hz butterworth BPF(band pass filter). As an ESS(energy storage system) of the proposed system, PEM fuel cells(Ballard NEXA, 1.2kw) is employed. Test results based on PSIM(power electro rues simulation tool) validate the proposed approach.
3상 불평형 전원 조건하의 능동전력필터를 위한 새로운 평균전력 알고리즘
정광식(Kwang-Sik Jung),정영국(Young-Gook Jung),김영철(Young-Cheol Kim),임영철(Young-Cheol Lim) 전력전자학회 2001 전력전자학술대회 논문집 Vol.2001 No.7
본 연구에서는 3상이 불평형된 전원 조건하에서 비선형 부하전류를 유효성분, 기본파 무효성분 그리고 왜형성분으로 분해한 후, 능동전력필터를 제어할 수 있는 새로운 평균전력 알고리즘을 제시하였다. 제안된 방법의 타당성을 입증하기 위해, 15% 불평형된 3상 전원 전압하에서 실험을 수행하였으며, 종전의 평균전력 알고리즘에 비하여 새로운 평균전력 알고리즘의 유용성을 입증할 수 있었다.
정영국(Young-Gook Jung) 한국조명·전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.10
본 연구에서는 전압품질에 민감한 설비를 위한 3상 Z-소스 동적 전압 보상기(Z-DVR : Z-Source Dynamic Voltage Restorer)를 제시하였다. 제안된 시스템은 수동필터와 Z-소스 토폴로지의 직렬형 능동필터로 구성된다. Z-DVR의 ESS(Energy Storage System)로는 친환경적인 고분자 전해질 연료전지(PEMFC : Proton Exchange Membrane Fuel Cells)를 사용하였다. 고조파 검출은 동기좌표계의 i<SUB>d</SUB>-i<SUB>q</SUB>이론에 의하였으며, 부하전압 보상을 위하여 PI제어를 사용하였다. 3상 전원이 모두 전압 sag가 발생하는 경우, PSIM에 의하여 제안된 방법과 배터리 스택을 적용하는 종전의 방법에 대하여 시뮬레이션을 수행하였으며, 전압 보상성능이 유사함을 알 수 있었다. 또한 전압 sag와 swell이 동시에 또는 독립적으로 발생하는 다양한 전원 조건하에서 제안된 시스템의 전압 보상 성능과 전압에 대한 %THD(%Total Harmonic Distortion)를 검토하였다. This paper proposes a three-phase Z-source dynamic voltage restorer (Z-DVR) to mitigate the voltage sag for the critical loads. The proposed system is composed of passive filter and Z-source topology inverter. As an ESS(Energy Storage System) of the proposed system is employed the Proton Exchange Membrane Fuel Cells (PEMFC). To calculate and control the harmonics and compensation voltage, i<SUB>d</SUB>-i<SUB>q</SUB> in dq rotating reference frame and PI controller are used. In case that three-phase voltage sags occurred, a PSIM simulation was done for the performance comparison of the conventional method employed battery stacks and proposed method. As a result, considering the voltage compensation performance, each method was nearly similar. Also, the compensation performance and the %THD(%Total Harmonic Distortion) result under the various source voltage conditions (sag or swell) were presented and discussed to show the performance of the proposed system.
3상 능동전력필터의 직류 링크 리플 전류의 센서리스 검출법
정영국(Young-Gook Jung) 한국조명·전기설비학회 2018 조명·전기설비학회논문지 Vol.32 No.4
In general, it is important to measure the ripple current of a DC capacitor, which is closely related to the lifetime of a power electronic converter. However, it is very difficult to measure directly with the current sensor because the DC capacitor is connected to the switching module at the shortest distance to minimize the inductance parasitic component of the DC capacitor and the overshoot of the switching device. This paper proposes a method to measure the ripple current of a DC capacitor of an active power filter indirectly without a sensor. The proposed method calculates the ripple current of the DC capacitor by sensorless method using the DC capacitor voltage, the output phase voltages and the compensation currents of the active power filter. The compensation current and DC voltage are directly detected to control the active power filter, and the compensation voltage is indirectly measured by using the switching function and DC voltage. The basic p-q power theory was applied to the 3-phase 3-wire active power filter and the DC capacitor current of the active power filter was measured for three-phase balanced, unbalanced power source condition, steady state and transient state. As a result, it was possible to indirectly measure the DC capacitor ripple current irrespective of the condition of the power source and the load variation, and the result was consistent with the results measured by the sensor.
입력 전류의 스위칭 맥동이 개선된 LCCT Z-소스 AC-AC 컨버터
정영국(Young-Gook Jung) 한국조명·전기설비학회 2022 조명·전기설비학회논문지 Vol.36 No.4
In the conventional trans-quasi Z-source AC-AC converter(TqZAC) method, the voltage gain can be improved by replacing the inductor of the Z-impedance network with a high-frequency transformer, but there is a problem in that a switching ripple occurs in the input current and the capacitor voltage. In this study, the Inductor-Capacitor-Capacitor-Trans Z-source AC-AC converter (LCCT-ZAC) method was presented to solve this problem. The proposed method replaces the conventional harmonic transformer with a three-winding high-frequency transformer and capacitor to alleviate the switching ripple problem of the previous method, while controlling the output voltage with in-phase boost and out-of-phase buck-boost for the input voltage. To prove the validity of this study, PSIM simulation and DSP-based experiments were performed. As a result, the output voltage was controlled by the in-phase boost mode at duty ratio D=0.15 and the out-of-phase buck mode at D=0.5. Also, the efficiency with respect to the change of duty ratio D under the load condition of 50Ω and the efficiency with respect to the load change under the condition of D=0.05 were almost the same between the two methods.