• Journal of electromagnetic engineering and science
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• 제15권2호
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• pp.89-96
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• 2015

This paper describes the application of a passive noise cancellation method to a prototype inductor-inductor-capacitor (LLC) resonant converter by placing a compensation winding in a transformer to reduce common mode noise. The connection method for the compensation winding is investigated. A circuit analysis is implemented for the displacement currents between the primary and secondary windings in the transformer. The analyzed displacement currents are verified by performing a circuit simulation and a proper compensation winding connection that reduces common mode noise is found. The measurement results show that common mode noise is reduced effectively up to 20 dB in the 1 to 7 MHz frequency region for the prototype LLC resonant converter by using the proposed passive noise cancellation method.

• 전력전자학회논문지
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• 제27권2호
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• pp.85-91
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• 2022

This study proposes a high efficiency bridgeless Power Factor Correction (PFC) converter with improved common mode noise characteristics. Conventional PFC has limitations due to low efficiency and enlarged heat sink from considerable conduction loss of bridge diode. By applying a Common Mode (CM) coupled inductor, the proposed bridgeless PFC converter generates less conduction loss as only a small magnetizing current of the CM coupled inductor flows through the input diode, thereby reducing or removing heat sink. The input diode is alternately conducted every half cycle of 60 Hz AC input voltage while a negative node of AC input voltage is always connected to the ground, thus improving common mode noise characteristics. With the aim to improve switching loss and reverse recovery of output diode, the proposed circuit employs Critical Conduction Mode (CrM) operation and it features a simple Zero Current Detection (ZCD) circuit for the CrM. In addition, the input current sensing is possible with the shunt resistor instead of the expensive current sensor. Experimental results through 480 W prototype are presented to verify the validity of the proposed circuit.

• 한국전기전자재료학회논문지
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• 제35권2호
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• pp.143-148
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• 2022

For the purpose of treating health checkups and recovery of patients in a super-aged society, hospitals use devices designed with a reduction circuit of electromagnetic waves associated with the specific absorption rate of electromagnetic waves absorbed by the human body. In this paper, we proposed a filter improvement design method capable of reducing electromagnetic waves. As a result of confirming the validity of the proposed technique through simulation and experimental results, the following result values were obtained. Applying the common-mode (CM) inductor 4 mH to a calibration circuit, noise decreased in a multiband spectrum. Using the differential mode(DM) inductor 40 µH element in the primary calibration circuit, the noise decreased by 15 dB or more in the 3 MHz band spectrum. Also, applying the Admittance Capacitance (Y-Cap) 10 nF element in the secondary calibration circuit resulted in the decrease by more than 30 dB in the band spectrum before 2 MHz. After using a common-mode inductor 4 mH element in the tertiary calibration circuit, it decreased by more than 15 dB in the band spectrum after 2 MHz.

• 한국전자파학회논문지
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• 제16권9호
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• pp.957-963
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• 2005

본 논문에서는 TSMC 0.25 ${\mu}m$ CMOS RF-Mixed mode 공정 기술을 이용하여 초고속 광통신 시스템의 수신부에 사용되는 광대역 transimpedance amplifier를 설계하였다. 특히 광대역을 구성하기 위해 cascode와 common-source 구조에 active inductor shunt peaking을 이용하여 설계 및 제작하였으며, 측정 결과 gain 변화 없이 -3 dB 대역폭 특성이 cascode는 0.8 GHz에서 $81\%$ 증가한 1.45 GHz, common-source는 0.61 GHz에서 $48\%$ 증가한 0.9 GHz 결과가 나왔으며, 전체 파워 소비는 바이어스 2.5 V를 기준으로 37 mW와 45 mW이며, transimpedance gain은 61 dB$\Omega$과 61.4 dB$\Omega$을 얻을 수 있었다. 그리고 input noise current density도 상용 TIA와 거의 비슷한 $5 pA/\sqrt{Hz}$와 $4.5 pA/\sqrt{Hz}$를 가지며, out put Return loss는 전 대역에서 -10 dB 이하의 정합 특성을 보였다. 그리고 전체 chip 사이즈는 $1150{\times}940{\mu}m^2$이다.

• 전력전자학회논문지
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• 제20권1호
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• pp.81-90
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• 2015

This paper investigates the droop control-based real and reactive power load sharing with a virtual inductor when the line impedance between inverter and Point of Common Coupling (PCC) is partly and unequally resistive in high-capacity systems. In this paper, the virtual inductor method is applied to parallel inverter systems with resistive and inductive line impedance. Reactive power sharing error has been improved by applying droop control after considering each line impedance voltage drop. However, in high capacity parallel systems with large output current, the reference output voltage, which is the output of droop controller, becomes lower than the rated value because of the high voltage drop from virtual inductance. Hence, line impedance voltage drop has been added to the droop equation so that parallel inverters operate within the range of rated output voltage. Additionally, the virtual inductor value has been selected via small signal modeling to analyze stability in transient conditions. Finally, the proposed droop method has been verified by MATLAB and PSIM simulation.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권5호
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• pp.265-270
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• 2006

In this paper EMI problems with induction motor drive system using multi-level inverters are investigated. The high power multi-level inverter usually operates with low switching frequency and produces large noises. Generally, EMI consists of the conduction component through source lines and emission component emitted to the space. This conduction component can be classified to the common-mode between source line and ground, and the normal-mode between lines. The EMI filters for the induction motor drive system are designed and implemented to reduce EMI noise. Finally the designed system is verified by the experiment. The experimental results show that both the normal mode and common mode noises are greatly reduced compared to the system without filters.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.794-796
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• 1993

This paper deals with the characteristic analysis of noise filter for the reduction of conduction noise, especially, common-mode noise. Attenuation in the system containing noise filter is analyzed and equivalent circuits for common- and differential- mode noise are derived. To clarify the effects by parasitic components of the inductor and capacitor, digital simulations using Design Center are carried out.

• 전기전자학회논문지
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• 제18권2호
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• pp.220-227
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• 2014

이 논문은 Dead-time을 갖는 톱니파 발생기를 이용하여 공통모드와 차동모드 피드백 루프를 구현한 Single-Inductor Dual-Output DC-DC Converter 설계에 관한 내용을 제시하고 있다. 제어회로에는 공통모드와 차동모드 피드백 루프를 Dead-time을 갖는 톱니파 발생기를 이용하여 동시에 사용하였다. 차동모드 피드백 루프에서 duty를 생성하기 위해서 전류 분배기 회로를 사용하여 공통모드 피드백에 의한 duty에 따라 dead-time이 유동적으로 변하는 톱니파형을 만드는 회로인 Dead-time을 갖는 톱니파 발생기를 추가하여 차동모드 피드백 회로를 구성하였다. 0.35um 공정을 사용하여 설계한 SIDO DC-DC Converter는 2.5V 입력으로부터 2.8V와 4.2V의 전압을 출력하며 최대 전력변환 효율은 95%이다. 출력간의 Cross regulation은 출력전류가 2배씩 증가할 경우 Boost1과 Boost2의 출력전압은 각각 3.57%, 4% 수준을 보이고 있다.

• 대한전자공학회논문지SD
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• 제44권8호
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• pp.22-29
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• 2007

[ $0.18{\mu}m$ ] CMOS공정을 이용하여 supply voltage 1.8V에서 2.5Gb/s 이상의 데이터 처리속도를 가지는 2:1 Multiplexer(MUX) 설계를 하였다. High speed 동작을 위한 주파수의 한계를 극복하기 위해서 4.7 nH의 on-chip micro spiral micro inductor $(20\times20{\mu}m2)$가 설계 되었고, 10개 이상의 inductor를 사용하고도 칩 면적 증가가 거의 없으면서 inductive peaking 효과를 극대화할 수 있었다. 칩 측정은 on-wafer로 진행되었고, micro spiral inductor가 있는 2:1 MUX와 그것이 없는 2:1 MUX 각각 측정하여 그 결과를 비교하였다. 측정결과 micro spiral inductor를 가진 2:1MUX가 rise time과 fall time이 1.25Gb/s에서는 rise time이 23%, fall time은 3%의 peaking 개선 효과가 있는 것을 확인하였다. 2.5Gb/s에서는 fall time이 약 5.3%, rise time 3.5%의 개선 효과를 보았다. 전체 소비전력은 61.2mW, 2.5Gb/s에서 voltage output swing은 $180mV_{p-p}$로 측정되었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.20-22
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• 2019

본 논문에서 공통모드 커플드 인덕터(Common Mode Coupled Inducter, CMCI)를 적용한 2단 직렬 위상천이 풀브리지 컨버터를 제안한다. 제안하는 위상천이 풀브리지 컨버터는 고주파수로 동작하며, 높은 입력전압에 대응할 수 있다. 풀브리지를 직렬로 쌓은 구조로 상단 풀브리지 컨버터와 하단 풀브리지 컨버터가 동시에 스위칭 한다. 2차측은 센터텝 정류기를 사용하여 풀브리지 정류기에 비해 다이오드 전압강하가 절반이라는 장점을 가진다. 또한, 변압기에 CMCI를 적용하여 1차측 상단과 하단의 전류 균형을 유지하도록 구성하였다. 제안하는 위상천이 풀브리지 컨버터의 5.8kW급 시제품을 제작하여 그 타당성을 검증하였다.