• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2159-2161
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• 1997

This paper presents the investigations and the reduction methods for EMI in the Elevator(E/L) system. In the large capacity E/L. Power factor controlled IGBT converter is used, so that the conducted EMI level is mostly determined by a high frequency input current. We suggest the low cost EMI countermearsure for E/L system using by a LCL filter ed a low cost noise filter.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.455-462
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• 2003

Switching PFC converters are widely used not only to comply the power quality specification but also for maximum efficiency. However switching PFC converters generate serious electromagnetic interference(EMI). In this paper to solve this problem, we applied the APW(Anti-Phase Winding) and RPWM(Random PWM) technique to PFC boost converter and obtained good results. Simulation and experimental results show the improved harmonics and reduced EMI effect in air-conditioner system.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.462-463
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• 2010

기존의 EMI 필터 설계 방식은 많은 가정을 전제로 설계되어 다양한 종류의 컨버터에 적용하기 어렵고, 특정 컨버터에만 적용할 수 있는 문제점이 있다. 이를 해결하기 위해 본 논문에서는 측정 대상 시료의 노이즈 원과 노이즈 소스 임피던스를 등가회로로 모델링한 후 EMI 필터에 사용되는 소자의 임피던스 모델을 이용하여 노이즈 소스 임피던스를 유추한다. 이를 이용하여 모든 컨버터에 적용될 수 있는 EMI 필터 설계 방법을 제시한다. 최종적으로 각 단계에서 실제 측정 결과 및 모의실험 결과를 제시하여 제안 방식의 타당성 및 유용성을 검증하였다.

• Journal of Korea Multimedia Society
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• v.18 no.3
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• pp.401-407
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• 2015

In this paper, we propose the method to eliminate EMI (Electro-Magnetic Interference) in ELF (Extremely Low Frequency) band below 2 KHz for extending the gesture-recognition distance of smart TVs to more than 3m using electric potential sensor. First, we measure the electric field generated from the back panel of a TV and propose the effective arrangement of two sets of differential sensors as well as the shielding method using metal fiber. Also, we eliminate the PLN (Power Line Noise) and other noise generated from the TV and sensors as well as surrounding environments using filters. Using the proposed EMI eliminating methods, we evaluate displacement ratio on measured signals according to distance between sensors and a moving hand. Experiment results show that our proposed method can extend the hand-gesture sensing distance using EPS (Electric Potential Sensor) up to more than 3m, which is enough to satisfy applicability of EPS based remote control to Smart TVs.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1326-1335
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• 2019

Common mode (CM) chokes are a crucial part in EMI filters for mitigating the electromagnetic interference (EMI) of switched-mode power supplies (SMPS) and for meeting electromagnetic compatibility standards. However, the parasitic capacitances of a CM choke deteriorate its high frequency filtering performance, which results in increases in the design cycle and cost of EMI filters. Therefore, this paper introduces a negative capacitance generated by a negative impedance converter (NIC) to cancel the influence of equivalent parallel capacitance (EPC). In this paper, based on a CM choke equivalent circuit, the EPCs of CM choke windings are accurately calculated by measuring their impedance. The negative capacitance is designed quantitatively and the EPC cancellation mechanisms are analyzed. The impedance of the CM choke in parallel with negative capacitances is tested and compared with the original CM choke using an impedance analyzer. Moreover, a CL type CM filter is added to a fabricated NIC prototype, and the insertion loss of the prototype is measured to verify the cancellation effect. The prototype is applied to a power converter to test the CM conducted noise. Both small signal and EMI measurement results show that the proposed technique can effectively cancel the EPCs and improve the CM filter's high frequency filtering performance.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2106-2107
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• 1998

This paper analyzes the sources of EMI noise, and Presents the noise reduction method using the modulation of switching frequency. Modulating the switching frequency makes the noise of side bands by shattering emission spectrum, and then can reduce the size of EMI filter at input line of power supply.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.167-170
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• 2003

This paper presents the results of a series of performance tests for the Stilting cryocooler. A free piston and free displacer(FPFD) Stilting cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM. Our coolers are specifically designed to work in the thermal imaging device and to meet requirements such as cooling capacity, COP and high reliability. In this work, Stilting cryocooler is designed, manufactured and fabricated, and performance characteristics for the vibration, acoustic noise, EMI and leak rate are evaluated. Vibration outputs are measured to 20KHz for compressor and expander, respectively. And, the objective of noise test is a noise level, less than 30㏈ at 5 m. EMI tests are carried out according to the standard MIL-STD-461C tests RE01 and RE02. Leak test for the Stilting cryocooler is performed by bombing method.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.1-7
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• 2008

This paper presents electromagnetic interference(EMI) suppression method applied on the direct current(DC) motor driver for power tail gate control. EMI noise is generated by the fast switching of power devices connected to electric loads. It has become a matter of concern because of the vast increase in the number and sophistication of electronic system in automotive environment. The proposed EMI reduction method is based on the principle of reducing the transient speed of power devices by changing the parameters of the driver circuit related to the power MOSFET. In this paper, power losses were calculated by loss equations and thermal simulation was used to evaluate the effect on printed circuit board. Based on these results, the DC motor driver was fabricated and tested. The proposed method can help to design a DC motor driver which allows it to obtain an acceptable compromise between power losses and EMI.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.5
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• pp.507-515
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• 2004

With the advent of fast power devices, the high dv/dt voltage produced by PWM inverts have been found to cause EMI noise, shaft voltage and bearing current. This paper describes the application of newly developed Conducted EMI reduction SVPWM technique in induction motor drives. The newly developed common mode voltage reduction SVPWM technique don't use any zero-vector states for inverter control, hence it can restrict the common mode voltage more than conventional PWM technique. The validity of the proposed technique by software approach is verified through simulation and experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.552-559
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• 1998

Conducted noise in power line contains both the common mode(CM) and differential mode(DM) noise. These two modes of noise are caused by different noise sources and paths. Therefore, CM/DM noise must be deal with individually in EMI filter. In this paper the technique to separate power line noise is presented, which can be used to measure both the CM and the DM noise from total generated noise. Also, noise-separator is designed and experimental results showed 30 dB above of separation performance in 10 kHz~10 MHz.