• Title/Summary/Keyword: Modulation method

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PWM Method of Voltage Type Converters with Large Modulation Ratio (변조율이 큰 전압형 컨버터의 PWM 변조방법)

  • 이사영;오봉환;김봉희;박현준;김길동;이승학;이미영
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.287-290
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    • 1998
  • This paper presents PWM method which modulates two third period only during one cycle of power converter. This method is compared with the conventionl sinusoidal modulation method applying to the power converter with large capacity necessitating low switching frequency. The presented modulation method enables to reduce power semiconductor rating, minimize switching loss, and improve the current wave form.

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Comparison of efficiency according to Non-inverting Buck-Boost Converter Modulation (단상 비 반전 벅-부스트 컨버터 모듈레이션 방법에 따른 효율 비교)

  • Yoon, Dongkwan;Cho, Younghoon
    • Proceedings of the KIPE Conference
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    • 2018.11a
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    • pp.203-204
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    • 2018
  • Conventional buck-boost converter has the disadvantage that the output voltage is inverted. The single phase non-inverting buck-boost converter(SPNIBBC) used four swithes has H-bridge type Circuit. The output voltage is not inverted. The SPNIBBC can be controlled by the single carrier method and the dual carrier method according to the modulation method. In this paper, we have fabricated the converter and compared the efficiency according to the modulation method.

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Analysis of Mobile System using Adaptive Modulation Method by Channel Forecast (채널예측에 의한 적응변조방식을 이용한 모바일 시스템 분석)

  • Lee, Myung-Soo;Cho, Dae-Jea
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.2
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    • pp.895-900
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    • 2011
  • To improve drawback of existing modulation method, in this paper, we propose the channel forecast method using adaptive modulation which can improve throughput of channel. This method adaptively changes modulation method to the change of channel environments. In proposed method, channel's characteristics are measured in realtime to determine code rate to the changes of demanded channel's bit error rate. If bit error rate is increased, this method reduce code rate to maintain maximum throughput. We analysis performance of proposed method by Matlab.

Modulated Fuel Feedback Control of a Fuel Injection SI Engine (연료량 변조법에 의한 연료분사식 가솔린엔진의 공연비 제어)

  • 박경석;박진일;고상근;노승탁;이종화
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.102-111
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    • 1996
  • For the air-fuel ratio control in a fuel injection SI engine, the Jump-Ramp control algorithm has been widely adopted by using the on/off type oxygen sensor. But the Jump-Ramp control method has limitation on treating the frequency and amplitude of the air-fuel ratio oscillation. This study suggests another feedback control logic named modulated fuel feedback control, which has a concept of pre-tuned air-fuel ratio oscillation. In the modulation method, the oxygen sensor output is not treated as on/off signal but as analog signal for feedback. By using the modulation method, the frequency and the amplitude of air-fuel ratio oscillation can be adjustable to some extent for improving the conversion efficiency of the Three-Way Catalyst. The result shows that the performance of the modulation method is better than that Jump-Ramp control method in reducing the amplitude of the air-fuel ratio oscillation as well as in increasing the frequency of the air-fuel ratio oscillation.

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Experimental study on the optical subscriber loop transmission link utilizing shared light sources and remote modulation method (공유광원 및 원격변조방법을 이용한 광가입자 전송링크에 관한 실험적 고찰)

  • 이용기;강용훈;채창준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.2
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    • pp.371-380
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    • 1997
  • A lot of efforts have been made to develop low-cost and reliable broadband optical subscriber loop systems. Here we propose a new loop system with shared ligh sources and remote modulation method. This system uses an external modulation method for both directions and all the light sources are maintained inside a central office. Moreover, the ligh source is not dedicated to each subsriber link but shared among many subscriber links. We expermentally demonstrated that one shared light source could accommodate about 2, 000 deownstream links(2.5 Gb/s per link), 500 upstream links(155 Mb/s per link).

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A Hybrid Modular Multilevel Converter Topology with an Improved Nearest Level Modulation Method

  • Wang, Jun;Han, Xu;Ma, Hao;Bai, Zhihong
    • Journal of Power Electronics
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    • v.17 no.1
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    • pp.96-105
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    • 2017
  • In this paper, a hybrid modular multilevel converter (MMC) topology with an improved nearest level modulation method is proposed for medium-voltage high-power applications. The arm of the proposed topology contains N series connected half-bridge submodules (HBSMs), one full-bridge submodule (FBSM) and an inductor. By exploiting the FBSM, half-level voltages are obtained in the arm voltages. Therefore, an output voltage with a 2N+1 level number can be generated. Moreover, the total level number of the inserted submodules (SMs) is a constant. Thus, there is no pulse voltage across the arm inductors, and the SM capacitor voltage is rated. With the proposed voltage balancing method, the capacitor voltage of the HBSM is twice the voltage of the FBSM, and each IGBT of the FBSM has a relatively low switching frequency and an equalized conduction loss. The capacitor voltage balancing methods of the two kinds of SMs are implemented independently. As a result, the switching frequency of the HBSM is not increased compared to the conventional MMC. In addition, according to a theoretical calculation of the total harmonic distortion of the electromotive force (EMF), the voltage quality with the presented method can be significantly enhanced when the SM number is relatively small. Simulation and experimental results obtained with a MMC-based inverter verify the validity of the developed method.

An Effective Carrier-Based Modulation Strategy to Reduce the Switching Losses for Indirect Matrix Converters

  • Tran, Quoc-Hoan;Lee, Hong-Hee
    • Journal of Power Electronics
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    • v.15 no.3
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    • pp.702-711
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    • 2015
  • In this paper, an effective carrier-based modulation (CBM) strategy to reduce the switching losses for indirect matrix converters (IMCs) is presented. The discontinuous pulse width modulation method is applied to decrease the switching numbers in one carrier cycle, and an optimum offset voltage is selected to avoid commutations of the high output phase currents. By decreasing the switching numbers along with avoiding commutation of the high currents, the proposed CBM strategy significantly reduces the switching losses in IMCs. In addition, the proposed CBM strategy is independent of load conditions, such as load power and power factor, and it has good performance in terms of the input/output waveforms. Simulation and experimental results are provided to verify the effectiveness of the proposed CBM strategy.

Fast Space Vector PWM Modulation of Multi-Level Inverter Without NTV Identification (NTV 식별과정 없는 멀티레벨 인버터의 신속한 공간벡터 PWM 변조 기법)

  • Jin, Sun-Ho;Oh, Jin-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.55 no.6
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    • pp.299-305
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    • 2006
  • In this paper, we suggest a new space vector PWM modulation method with very short processing time which does not need identification of nearest three vectors(NTV) and duty ratio for each vector. The suggested PWM method makes mean value of phase voltage to be same as reference during every modulation period by use of a triangle in small hexagon on multi-level vector space. This paper described the suggested modulation method can be successfully applied to the space vector modulation use of multi-level inverter by computer simulations and experiments.

Novel Predictive Current Control Pulse Width Modulation Method for Matrix Convertors (매트릭스 컨버커를 위한 새로운 예측 전류제어 펄폭 변조 방법)

  • Li, Yulong;Choi, Nam-Sup;Han, Byung-Moon;Yang, Seung-Chul
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.65-67
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    • 2008
  • A new pulse width modulation method based on predictive current control strategy is proposed to modulate matrix converters. The predictive current controller utilizes a discrete-time model to predict the future values of output currents and generates proper duty-ratios ta minimize the output current errors. The proposed method uses continuous carrier and establishes a predictive current controller to predetermine duty ratio signal for directly generating gating signals an thus is named "predictive current control PWM(PCCPWM)". The modulation algorithm nd the required equations are derived by using average concept over one switching period. Thus it can be easily extended to other matrix converter topologies, especially with neutral connections, such as sing le-phase ad two-phase matrix converters. The feasibility and validity of the proposed strategy are verified by computer simulation and experimental results.

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Parallel Resonant Soft Switching Inverter based on Delta-Modulation Method (Delta-Modulation 기법을 적용한 병렬 공진형 소프트 스위칭 인버터)

  • Choi, Kwang-Soo;Kim, Young-Ho;Kim, Jun-Gu;Won, Chung-Yuen;Jung, Yong-Chae;Oh, Dong-Sung
    • Proceedings of the KIPE Conference
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    • 2009.11a
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    • pp.212-214
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    • 2009
  • In this paper, we have proposed a Parallel Resonant Soft Switching Inverter based on Delta-Modulation Method. The conventional full-bridge inverter generates switching losses due to the hard switching. The proposed inverter operates soft switching using a DC-link switch and resonant circuit. So, all of the switches in the proposed inverter operates soft switching. Therefore the proposed inverter can reduce not only switching loss but also capacity and size of passive devices due to the resonant elements. The validity of the proposed inverter is verified thorough the theoretical analysis and simulation.

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