• 제목/요약/키워드: discontinuous PWM (DPWM)

검색결과 12건 처리시간 0.019초

DPWM 방식을 적용한 3상 계통 연계 인버터의 LCL-필터 설계 (Design of LCL-filter for Grid-Connected Three-Phase Inverters Using a Discontinuous PWM Method)

  • 이정록;서승규;이교범
    • 전기학회논문지
    • /
    • 제65권3호
    • /
    • pp.419-427
    • /
    • 2016
  • This paper proposes a design method of LCL-filter for a grid-connected three-phase inverter using a discontinuous PWM (DPWM) method. When using a DPWM method, many harmonic voltages are generated in the inverter output compared to a continuous PWM (CPWM) method. Therefore, an optimized grid-connected filter design is required for a DPWM method. The proposed design method provides generalized formula to design accurate LCL-filter without trial and error procedures. An inverter side inductance is designed by analyzing the current ripple injected to the grid. The Optimized parameters of LCL-filter can be designed by analyzing the total harmonic distortion (THD) and the ripple attenuation factor of the output current. The proposed LCL filter design method is demonstrated by simulation and experimental results.

Discontinuous PWM Scheme for Switching Losses Reduction in Modular Multilevel Converters

  • Jeong, Min-Gyo;Kim, Seok-Min;Lee, June-Seok;Lee, Kyo-Beum
    • Journal of Power Electronics
    • /
    • 제17권6호
    • /
    • pp.1490-1499
    • /
    • 2017
  • The modular multilevel converter (MMC) is generally considered to be a promising topology for medium-voltage and high-voltage applications. However, in order to apply it to high-power applications, a huge number of switching devices is essential. The numerous switching devices lead to considerable switching losses, high cost and a larger heat sink for each of the switching device. In order to reduce the switching losses of a MMC, this paper analyzes the performance of the conventional discontinuous pulse-width modulation (DPWM) method and its efficiency. In addition, it proposes a modified novel DPWM method for advanced switching losses reduction. The novel DPWM scheme includes an additional rotation method for voltage-balancing and power distribution among sub modules (SMs). Simulation and experimental results verify the effectiveness and performance of the proposed modulation method in terms of its switching losses reduction capability.

3-level inverter를 위한 새로운 Carrier-Based DPWM 기법 (The Novel Carrier-Based DPWM Method for 3-level Inverter)

  • 강대욱
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2000년도 전력전자학술대회 논문집
    • /
    • pp.347-350
    • /
    • 2000
  • This paper deals with the novel DPWM(discontinuous PWM) for 3-level inverter. Although DPWM methods generate higher harmonics than SVPWM they are of special interest because of their lower switching losses. And in the high modulation region the harmonic characteristics of DPWM is superior to the that of CPWM. However when DPWM applies to the 3-level inverter there is the problem that the output state is varied suddenly in the low modulation region($\textrm{m}_{I}$=0~0.5) The novel DPWM that this problem improves will be introduced.

  • PDF

불연속 변조 기법을 이용한 고속철도 추진제어장치용 단상 PWM 컨버터 (Single Phase PWM Converter For High-Speed Railway Propulsion System Using Discontinuous PWM)

  • 송민섭
    • 한국철도학회논문집
    • /
    • 제20권4호
    • /
    • pp.448-457
    • /
    • 2017
  • 본 논문에서는 불연속 변조 기법을 이용한 고속철도 추진제어장치용 단상 PWM 컨버터에 대해 연구하였다. 기존 PWM 컨버터는 대 전력 특성으로 인해 스위칭 손실을 줄이기 위해 주파수 변조지수를 10 이하로 낮게 사용함에 따라 제어의 대역폭이 감소하고, 안정적인 역률 제어를 위해 추가의 보상 기법을 필요로 하는 등의 문제점을 가지고 있다. 이를 해결하기 위해 3상 PWM 인버터에서 사용하는 불연속 변조 기법을 단상 PWM 컨버터에 적용하였다. 제안한 방식은 옵셋 전압 기법을 활용하여 간단히 구현될 수 있으며 동일 스위칭 손실 대비 주파수 변조 지수를 2배 증가시켜 제어 특성을 향상시키고 스위치 간의 동특성도 동일하게 가져갈 수 있다. 100 kW급 PWM 컨버터에 대한 시뮬레이션을 통해 제안한 불연속 변조 기법에 대한 타당성을 검증하였다.

A Simple Control Strategy for Balancing the DC-link Voltage of Neutral-Point-Clamped Inverter at Low Modulation Index

  • C.S. Ma;Kim, T.J.;D.W. Kang;D.S. Hyun
    • Journal of Power Electronics
    • /
    • 제3권4호
    • /
    • pp.205-214
    • /
    • 2003
  • This paper proposes a simple control strategy based on the discontinuous PWM (DPWM) to balance the DC-link voltage of three-level neutral-point-clamped (NPC) inverter at low modulation index. It introduces new DPWM methods in multi-level inverter and one of them is used for balancing the DC-link voltage. The current flowing in the neutral point of the DC-link causes the fluctuation of the DC-link voltage of the NPC inverter. The proposed DPWM method changes the path and duration time of the neutral point current, which makes the overall fluctuation of the DC-link voltage zero during a sampling time of the reference voltage vector. Therefore, by using the proposed strategy, the voltage of the DC-link can be balanced fairly well and the voltage ripple of the DC-link is also reduced significantly. Moreover, comparing with conventional methods which have to perform the complicated calculation, the proposed strategy is very simple. The validity of the proposed DPWM method is verified by the experiment.

Reducing Switching Losses in Indirect Matrix Converter Drives: Discontinuous PWM Method

  • Bak, Yeongsu;Lee, Kyo-Beum
    • Journal of Power Electronics
    • /
    • 제18권5호
    • /
    • pp.1325-1335
    • /
    • 2018
  • This paper presents a discontinuous pulse width modulation (DPWM) method to reduce switching losses in an indirect matrix converter (IMC) drive. The IMC has a number of power semiconductor switches. In other words, it consists of a rectifier stage and an inverter stage for AC/AC power conversion, which are composed of 12 and 6 switching devices, respectively. Therefore, the switching devices of the IMC suffer from high switching losses in the IMC drives. Various topologies to reduce switching losses have been studied by eliminating a number of switches from the rectifier stage. In this study, in contrast to prior research, a DPWM method is presented to reduce the switching losses of the inverter stage. The effectiveness of the proposed method to reduce switching losses in IMC drives is verified by simulations and experimental results.

Neutral-Point-Clamped 인버터의 저 변조지수에서 DC 링크 전압 균형을 위한 간단한 컨트롤 기법 (A Simple Control Strategy for Balancing the DC-link Voltage of Neutral-Point-Clamped Inverters at low modulation index)

  • 마창수;김태진;강대욱;현동석
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2003년도 춘계전력전자학술대회 논문집(2)
    • /
    • pp.560-564
    • /
    • 2003
  • This paper proposes a simple control strategy based on the discontinuous PWM(DPWM) to balance the DC-link voltage of three-level Neutral-Point-Clamped(WPC) inverters at low modulation index. New DPWM methods in multi-level inverter are also introduced. The proposed DPWM method changes the path and duration to flow the neutral point current out of or into neutral point of the DC-link and it makes the overall fluctuation of the DC-link voltage zero during a sampling time of reference voltage vector. Therefore, the voltage of the DC-link can be balanced fairly well and also the voltage ripple of the DC-link is reduced significantly. Moreover, comparing with conventional methods, the proposed strategy is very simple. The validity of the proposed DPWM method is verified by experiment

  • PDF

14.3kW급 3-레벨 NPC 인버터 각 SVPWM 효율 및 THD 비교 분석 (Comparative analysis of efficiency and THD on SVPWM using 14.3kW 3-level NPC inverter)

  • 이춘복;현승욱;이희준;신수철;김영렬;원충연
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2013년도 추계학술대회 논문집
    • /
    • pp.107-108
    • /
    • 2013
  • 본 논문에서는 3-레벨 NPC(Neutral Point Clamped) 인버터에서 사용되는 SVPWM(Space Vector Pluse Width Modulation)기법들 중 옵셋전압을 이용한 대칭 SVPWM과 효율을 높이기 위한 전압 지령 벡터를 계산한 $120^{\circ}$ DPWM(Discontinuous PWM)과 $60^{\circ}(+30^{\circ})$ DPWM을 비교 분석하였다. 각 SVPWM간의 효율 및 THD를 비교 분석 하였고 이를 통해 시뮬레이션으로 스위칭 방식에 따라 비교하여 효율 및 THD 결과를 도출하였다.

  • PDF

Consideration of the Carrier Based Signal Injection Method in Three Shunt Sensing Inverters for Sensorless Motor Control

  • Jung, Sungho;Ha, Jung-Ik
    • Journal of Power Electronics
    • /
    • 제16권5호
    • /
    • pp.1791-1801
    • /
    • 2016
  • This paper considers a carrier based signal injection method for use in the three shunt sensing inverter (TSSI) for sensorless motor control. It also analyzes the loss according to the injection axis of the voltage signal. To remove both the phase current and rotor position sensors, a sensorless method and a phase current reconstruction method can be simultaneously considered. However, an interaction between the two methods can be incurred when both methods inject voltage signals simultaneously. In this paper, a signal injection based sensorless method with the 120° OFF Discontinuous PWM (DPWM) is implemented in a TSSI to avoid this interaction problem. Since one leg does not have a switching event for one sampling period in the 120° OFF DPWM, the switching loss is altered according to the injection axis. The switching loss in the d-axis injection case can be up to 32% larger than that in the q-axis injection case. Other losses according to the injection axis are also analyzed.

전압변조기법 변경을 이용한 유도전동기의 스위칭 손실 및 토크 리플 저감 방법 (Torque Ripple Reduction and Switching Loss Reduction Method for Induction Motors by Hybrid PWM)

  • 이성호;김솔준;이준석;이장무
    • 전력전자학회:학술대회논문집
    • /
    • 전력전자학회 2018년도 추계학술대회
    • /
    • pp.189-190
    • /
    • 2018
  • 본 논문에서는 유도전동기의 토크 리플 및 스위칭 손실 저감을 위해 전압변조기법인 공간벡터변조(Space Vector Pulse Width Modulation, SVPWM) 기법과 불연속전압변조(Discontinuous Pulse Width Modulation, DPWM) 기법을 혼합하여 사용하는 새로운 변조기법을 제안한다. 제안하는 방식은 지령전압이 최대인 부근에서 SVPWM 기법을 사용하며, 나머지 구간에서는 DPWM 기법을 적용한다. 전 구간 단일기법을 적용할 때와 비교하여 제안하는 방식은 토크 리플 및 스위칭 손실을 효율적으로 저감시킬 수 있으며 시뮬레이션을 통해 타당성을 검증한다.

  • PDF