• Title/Summary/Keyword: Harmonics suppression

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Design and Fabrication of a Minimum Insertion Loss Parallel-Coupled-Line-Filter for the Suppression of LO Harmonics (최소 삽입 손실을 갖는 국부 발진기 고조파 제거를 위한 병렬 결합 전송 선로 대역 여파기의 설계 및 제작)

  • Kim, Hyun-Mi;Yang, Seong-Sik;Oh, Hyun-Seok;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.5 s.120
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    • pp.486-495
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    • 2007
  • In this paper, we present the design procedure of BPF(Band Pass Filter) for the suppression of LO(Local Oscillator) harmonics. The required suppression at given harmonics is the key issues in such a filter design, while the bandwidth and the suppression of the unwanted signals are more important in the conventional RF filter design. In LO filter design the bandwidth is used for the minimization of the insertion loss for the desired signal. In addition, we propose the novel tuning procedure based on Momentum to consider the unknown parasitic effects, which usually are not included in the circuit design step and results in undesirable and frustrating tuning after fabrication.

Modified Wilkinson Power Divider for Multiple Harmonics Suppression

  • Kang In-Ho;Xu Hai-Yan
    • Journal of Navigation and Port Research
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    • v.29 no.7
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    • pp.615-618
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    • 2005
  • A new structure of the Wilkinson power divider that can suppress multiple harmonics output is presented The power divider consists of T-type or $\pi$-type capacitive loads and shunt resistors. Experimental results show that this power divider suppresses the second and the third harmonic components to less than -38dB, while maintaining the characteristics of a conventional Wilkinson power divider, featuring an equal power split, a simultaneous impedance matching at all ports and a good isolation between output ports.

A study on the Development and Field Application of Passive Filter for Harmonic Suppression (고조파 억제용 수동필터의 현장 적용화 연구)

  • Park, H.J.;Kang, C.S.;Lee, H.G.
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.89-91
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    • 1999
  • The use of electronic power unit essentially result in serious problems by harmonics. To reduce the effect by harmonics, we propose passive filter system which can control each harmonic filters individually. So, additional devices to detect and analyze harmonics were installed to filter system. According to measured data in the field, we calculated the values of filter components and verified them by computer simulation. After installation of filter system in the field, we could reduce harmonics and improve power factor.

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Koch Fractal Shape Microstrip Bandpass Filters on High Resistivity Silicon for the Suppression of the 2nd Harmonic

  • Kim, Ii-Kwon;Kingsley Nickolas;Morton Matthew A.;Pinel Stephane;Papapolymerou John;Tentzeris Manos M.;Laskar Joy;Yook, Jong-Gwan
    • Journal of electromagnetic engineering and science
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    • v.6 no.4
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    • pp.235-243
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    • 2006
  • In this paper, the fractal shape is applied to microstrip band pass filters and integrated on a high-resistivity Si substrate to solve conventional $2^{nd}$ harmonic problem. Conventional microstrip coupled line filters are popular in RF front ends, because they can be easily fabricated and integrated with other RF components. However, they typically have large second harmonics that can cause unwanted interference in interested frequency bands. Without any additional filters, the proposed Koch shape filters have suppressed the $2^{nd}$ harmonics by about -40 dB, so they can be used in systems such as direct conversion receiver with stringent harmonic suppression requirements.

A Low-loss Phase Shifter with Harmonics Suppression Using Compact Hybrid Coupler (소형 하이브리드 커플러를 이용한 고조파가 억압된 저손실 위상 변위기)

  • Yoon, Ki-Cheol;Ji, Seung-Han;Lee, Jong-Chul
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.14 no.6
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    • pp.110-116
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    • 2015
  • In this paper, a compact low-loss reflector-type phase shifter with harmonic suppression using meander T-shaped branch-line coupler is suggested. The compact coupler for the phase shifter has a size of $22.2{\times}14.9mm^2$ while a conventional branch coupler has a size of $32.6{\times}27.8mm^2$. The phase shifter shows insertion losses of 0.19-0.28 dB at the center frequency of 2.1 GHz, and a measured maximum phase shift of $137^{\circ}$.

Design of a Broad Band-pass Filter with Stubs for Harmonics Suppression using the FSCS (FSCS를 이용한 고조파가 억제된 광대역 스터브 대역통과 여파기의 설계)

  • Choi, Young-Gu;Kim, Bok-Ki
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.1
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    • pp.103-109
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    • 2008
  • In this papaer, a new type of ${\lambda}_g/4$ short stub band pass filter and ${\lambda}_g/2$ open stub band pass filter are purposed. Both are designed using FSCS technique for harmonic suppression. The proposed filters that used FSCS technique and a broadband stop filter is integrated to band pass filter to suppress the harmonics. The BSF are also placed between stubs so that the size is larger than prevent as compared to conventional one. The propose filters have center frequency of 5.8 GHz, bandwidth of 50% and harmonics suppressin is 120% has in bandwith. The measurement results in the case of ${\lambda}_g/4$ short stub filter, insertion loss of 0.5 dB, return loss of 14 dB are achieved and in the case of ${\lambda}_g/2$ open stub filter, loss of 0.8 dB, return loss of 14.4 dB are achieved. The simulation results and the measurement results are almost the same.

Parallel Feedback Oscillator for Strong Harmonics Suppression and Frequency Doubler (고조파 억압을 위한 병렬 궤환형 발진기와 주파수 체배기)

  • Lee, Kun-Joon;Ko, Jung-Pil;Kim, Young-Sik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.2A
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    • pp.122-128
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    • 2005
  • In this paper, a low noise parallel feedback oscillator for harmonic suppression and a frequency doubler are designed and implemented. As the fundamental signal of the oscillator for frequency doubling is extracted between the dielectric resonator (DR) filter and the gate device of the active device, the undesired harmonics at the output of the oscillator is remarkably suppressed. The fundamental signal of the oscillator for frequency doubling directly feeds to the frequency doubler without an additional band pass filter for harmonic suppression. The second harmonic suppression of -47.7 dBc at the oscillator output is achieved, while the fundamental suppression of -37.5 dBc at the doubler output is obtained. The phase noise characteristics are -80.3 dBc/Hz and -93.5 dBc/Hz at the offset frequency of 10 KHz and 100 KHz from the carrier, respectively.

Circulating Current Harmonics Suppression for Modular Multilevel Converters Based on Repetitive Control

  • Li, Binbin;Xu, Dandan;Xu, Dianguo
    • Journal of Power Electronics
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    • v.14 no.6
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    • pp.1100-1108
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    • 2014
  • Modular multilevel converters (MMCs) have emerged as the most promising topology for high and medium voltage applications for the coming years. However, one particular negative characteristic of MMCs is the existence of circulating current, which contains a dc component and a series of low-frequency even-order ac harmonics. If not suppressed, these ac harmonics will distort the arm currents, increase the power loses, and cause higher current stresses on the semiconductor devices. Repetitive control (RC) is well known due to its distinctive capabilities in tracking periodic signals and eliminating periodic errors. In this paper, a novel circulating current control scheme base on RC is proposed to effectively track the dc component and to restrain the low-frequency ac harmonics. The integrating function is inherently embedded in the RC controller. Therefore, the proposed circulating current control only parallels the RC controller with a proportional controller. Thus, conflicts between the RC controller and the traditional proportional integral (PI) controller can be avoided. The design methodologies of the RC controller and a stability analysis are also introduced. The validity of the proposed circulating current control approach has been verified by simulation and experimental results based on a three-phase MMC downscaled prototype.

A Novel Hybrid Active Power Filter with a High-Voltage Rank

  • Li, Yan;Li, Gang
    • Journal of Power Electronics
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    • v.13 no.4
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    • pp.719-728
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    • 2013
  • A novel hybrid active power filter (NHAPF) that can be adopted in high-voltage systems is proposed in this paper. The topological structure and filtering principle of the compensating system is provided and analyzed, respectively. Different controlling strategies are also presented to select the suitable strategy for the compensation system. Based on the selected strategy, the harmonic suppression function is used to analyze the influence of system parameters on the compensating system with MATLAB. Moreover, parameters in the injection branch are designed and analyzed. The performance of the proposed NHAPF in harmonic suppression and reactive power compensation is simulated with PSim. Thereafter, the overall control method is proposed. Simulation analysis and real experiments show that the proposed NHAPF exhibits good harmonic suppression and reactive power compensation. The proposed compensated system is based on the three-phase four-switch inverter, which is inexpensive, and the control method is verified for validity and effectiveness.