• Title/Summary/Keyword: power-type sequence

Search Result 95, Processing Time 0.024 seconds

Research on Carried-Based PWM with Zero-Sequence Component Injection for Vienna Type Rectifiers

  • Ma, Hui;Feng, Mao;Tian, Yu;Chen, Xi
    • Journal of Power Electronics
    • /
    • v.19 no.2
    • /
    • pp.560-568
    • /
    • 2019
  • This paper studies the inherent relationship between currents and zero-sequence components. Then a precise algorithm is proposed to calculate the injected zero-sequence component to control the DC-Link neutral-point voltage balance, which can result in a more efficient and flexible neutral point voltage balance with a desirable performance. In addition, it is shown that carried-based PWM with the calculated zero-sequence component scheme can be equivalent to space-vector pulse-width modulation (SVPWM). Based on the proposed method, the optimal zero-sequence component of the feasible modulation indices is analyzed. In addition, the unbalanced load limitation of the DC-Link neutral-point voltage balance control is also revealed. Simulation and experimental results are shown to verify the validity and practicality of the proposed algorithm.

A Low-Power Bus Transmission Scheme for Packet-Type Data (패킷형 데이터를 위한 저전력 전송방법)

  • 윤명철
    • Journal of the Institute of Electronics Engineers of Korea SD
    • /
    • v.41 no.7
    • /
    • pp.71-79
    • /
    • 2004
  • Packet-type data transmission is characterized by the continuous transmission of massive data with relatively constant rate. In such transmission, the dynamic power consumed on buses is influenced by the sequence of transmitted data. A new coding scheme called Sequence-Switch Coding (SSC) is proposed in this paper. SSC reduces the number of bus transitions in the transmission of packet-type data by changing the sending order of the data. Some simple algorithms are presented, In. The simulation results show that SSC outperforms the well-known Bus-Invert Coding with these algorithms. SSC is not a specific algerian but a method to reduce the number of bus-transitions. There could be lots of algorithms for realizing SSC. The variety of SSC algorithms provides circuit designers a wide range of trade-off between performance and circuit complexity.

Droop Control Scheme of a Three-phase Inverter for Grid Voltage Unbalance Compensation

  • Liu, Hongpeng;Zhou, Jiajie;Wang, Wei;Xu, Dianguo
    • Journal of Power Electronics
    • /
    • v.18 no.4
    • /
    • pp.1245-1254
    • /
    • 2018
  • The stability of a grid-connected system (GCS) has become a critical issue with the increasing utilization of renewable energy sources. Under grid faults, however, a grid-connected inverter cannot work efficiently by using only the traditional droop control. In addition, the unbalance factor of voltage/current at the common coupling point (PCC) may increase significantly. To ensure the stable operation of a GCS under grid faults, the capability to compensate for grid imbalance should be integrated. To solve the aforementioned problem, an improved voltage-type grid-connected control strategy is proposed in this study. A negative sequence conductance compensation loop based on a positive sequence power droop control is added to maintain PCC voltage balance and reduce grid current imbalance, thereby meeting PCC power quality requirements. Moreover, a stable analysis is presented based on the small signal model. Simulation and experimental results verify the aforementioned expectations, and consequently, the effectiveness of the proposed control scheme.

New low-complexity segmentation scheme for the partial transmit sequence technique for reducing the high PAPR value in OFDM systems

  • Jawhar, Yasir Amer;Ramli, Khairun Nidzam;Taher, Montadar Abas;Shah, Nor Shahida Mohd;Audah, Lukman;Ahmed, Mustafa Sami;Abbas, Thamer
    • ETRI Journal
    • /
    • v.40 no.6
    • /
    • pp.699-713
    • /
    • 2018
  • Orthogonal frequency division multiplexing (OFDM) has been the overwhelmingly prevalent choice for high-data-rate systems due to its superior advantages compared with other modulation techniques. In contrast, a high peak-to-average-power ratio (PAPR) is considered the fundamental obstacle in OFDM systems since it drives the system to suffer from in-band distortion and out-of-band radiation. The partial transmit sequence (PTS) technique is viewed as one of several strategies that have been suggested to diminish the high PAPR trend. The PTS relies upon dividing an input data sequence into a number of subblocks. Hence, three common types of the subblock segmentation methods have been adopted - interleaving (IL-PTS), adjacent (Ad-PTS), and pseudorandom (PR-PTS). In this study, a new type of subblock division scheme is proposed to improve the PAPR reduction capacity with a low computational complexity. The results indicate that the proposed scheme can enhance the PAPR reduction performance better than the IL-PTS and Ad-PTS schemes. Additionally, the computational complexity of the proposed scheme is lower than that of the PR-PTS and Ad-PTS schemes.

Presentation of a Fault Detecting Method for Power Transmission Line using M-sequence

  • Nishiyama, E.;Kuwanmi, K.
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2001.10a
    • /
    • pp.86.2-86
    • /
    • 2001
  • The method of pinpointing the place of the abnormalities of a power transmission system analyzes the voltage and the current information from the both ends of a power [1-2]. Now, there are only current and a voltage measuring instrument every about 20km, and the present condition is specifying the breaking down point by viewing of a worker in it. In this research, a power line circuit is assumed to be a line type system, and M-sequence is impressed to the end, it receives at other ends, the crosscorrelation function of input and output is taken, an impulse response is calculated, and the method in comparison with the time of normal is proposed. By this technique ...

  • PDF

Grid-connected Inverter Control Algorithm for Torque Ripple Compensation in Doubly-Fed Induction-type Wind Power Generation System (전원 전압 불평형시 이중여자 유도형 풍력발전 시스템의 토크 리플 저감을 위한 계통연계 인버터 제어 알고리즘)

  • Jeong, Byoung-Chang;Song, Seung-Ho
    • Proceedings of the KIEE Conference
    • /
    • 2005.10c
    • /
    • pp.317-319
    • /
    • 2005
  • In this paper, control algorithm for torque ripple compensation in DFIG wind power generation system is proposed. A simple PI controller is designed for the negative sequence voltage cancellation using negative sequence currents in the grid-side converter. As a result, the stator voltage contains only the positive sequence components and the torque pulsation of the generator is effectively compensated. Propose algorithm is confirmed with PSCAD simulation model.

  • PDF

A Novel Skewed-Type Iron Slot Wedge for Permanent Magnet Synchronous Generators for Improving Output Power and Reducing Cogging Torque

  • Kang, Sun-Il;Moon, Jae-Won;You, Yong-Min;Lee, Jin-Hee;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.1
    • /
    • pp.243-250
    • /
    • 2015
  • This paper proposes a novel skewed-type iron slot wedge that can improve both the cogging torque and the output power of a permanent magnet synchronous generator (PMSG). Generally the open slot structure is adopted in a PMSG due to its convenient winding work, but the high cogging torque is undesired. Firstly, an iron slot wedge was utilized to reduce the cogging torque of an open slot type PMSG. However, the output power of the machine decreased rapidly with this method. Thus, a proposed skewed type iron slot wedge is presented to improve the output power as well as the cogging torque as compared to the open slot type. Shape optimization of the skewed-type iron slot wedge is performed to simultaneously maximize the output power and reduce the cogging torque. The Kriging model based on the Halton sequence method and a genetic algorithm are used to optimize the design.

The Development of 30KVA IGBT-type Customer STATCOM (수용가용 30kVA급 IGBT형 STATCOM 개발)

  • Lim, Su-Saeng;Lee, Eun-Woong;Kim, J.K.;Sohn, H.K.;Cho, H.K.;Jeong, J.H.
    • Proceedings of the KIEE Conference
    • /
    • 2002.07b
    • /
    • pp.657-659
    • /
    • 2002
  • Power quality refers to voltage quality and current quality. Voltage quality means supply reliance such as voltage sag, voltage swell. and short-time interruption. Current quality is related to power factor, harmonic distortion, negative-sequence and zero-sequence current. We fabricated Customer STATCOM to improve current quality such as reactive power, harmonic distortion, and load imbalance. In this paper. We summarize the spec, of STATCOM. its hardware configuration, and control system.

  • PDF

Hybrid-Type Active Power Filters for Compensating Harmonic Current and Unbalanced Source Voltages (고조파 전류와 불평형 전원전압 보상을 위한 복합형 능동전력 필터)

  • Lee, Ji-Myeong;Lee, Dong-Chun
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.51 no.5
    • /
    • pp.249-257
    • /
    • 2002
  • In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for the combined system of series active and shunt passive power filter is proposed, where no low/high-pass filters are used in deriving the reference voltage for compensation. The phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. In order to remove the phase delay in generating the reference voltage for compensation, the reference of 5th and 7th harmonic components is predicted one-sampling ahead. The validity of the proposed scheme has been verified for 3[kVA] proto-type active power filter system.