电气工程学报 ›› 2020, Vol. 15 ›› Issue (1): 29-35.doi: 10.11985/2020.01.004

所属专题: 特邀专栏:微电网功率变换与稳定控制

• 特邀专栏: 微电网功率变换与稳定控制 • 上一篇    下一篇

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下垂控制微电网的无功补偿失稳机理及抑制对策

施云杰,冯夏云(),汪飞,张笠君,李玉菲   

  1. 上海大学自动化系上海市电站自动化技术重点实验室 上海 200044
  • 收稿日期:2019-10-30 出版日期:2020-03-25 发布日期:2020-05-13
  • 通讯作者: 冯夏云 E-mail:arthur@shu.edu.cn
  • 作者简介:施云杰,男,1996年生,硕士研究生。主要研究方向为电能质量补偿及IGBT热电联合仿真研究。E-mail:1003689826@qq.com|汪飞,男,1981年生,博士,教授。主要研究方向为微电网、能量路由、IGBT寿命预测等。E-mail:f.wang@i.shu.edu.cn|张笠君,男,1990年生,博士。主要研究方向为虚拟同步发电机。E-mail:lijunzhang@shu.edu.cn|李玉菲,女,1995年生,博士研究生。主要研究方向为直流微电网建模与仿真。E-mail:13774316513@163.com

Instability Mechanism and Control Measures of Reactive Compensation in Islanded Microgrid Based on Droop Control

SHI Yunjie,FENG Xiayun(),WANG Fei,ZHANG Lijun,LI Yufei   

  1. Shanghai Key Laboratory of Power Station Automation Technology, Shanghai University, Shanghai 200044 China
  • Received:2019-10-30 Online:2020-03-25 Published:2020-05-13
  • Contact: FENG Xiayun E-mail:arthur@shu.edu.cn

摘要:

出于线路经济运行与传输损耗的要求,就孤岛微电网的无功补偿,研究了基于下垂控制的孤岛微电网采用无功补偿电容器进行无功补偿时的谐振问题。首先,采用小信号分析法建立了下垂控制逆变器输出阻抗模型,揭示了下垂功率控制环(主要是Q-U控制参数)仅影响逆变器低频段输出阻抗。然后,基于阻抗的稳定性判据分析了采用电容器进行无功补偿时的孤岛微电网稳定性问题。研究表明,采用电容器进行无功补偿时,将使系统失稳。最后提出在电流内环中引入电容电流反馈控制,实现输出阻抗重塑,抑制谐振,并设计了一台3 kW变换器,验证了所建输出阻抗模型及谐振抑制方法的正确性。

关键词: 电容器无功补偿, 下垂控制, 孤岛微电网, 阻抗稳定性判据, 谐振抑制

Abstract:

For the line economical operation and lower transmission loss requirements, on the part of reactive compensation of islanded microgrid, resonance problems among droop control inverter and the reactive compensation capacitor are studied. Firstly, output impedance of droop control inverter is obtained by small signal method, it is disclosed that droop control inverter especially Q-U control factor is mainly factor, which would affect the output impedance value at lower frequency band. Then, the stability of islanded microgrid is analyzed by impedance-based specifications when reactive power capacitors are emulated for reactive power compensation. It is shown that the grid is unstable if the reactive power capacitor is existed for reactive compensation. Finally, harmonic suppression method based on capacitor current feedforward control at current inner loop is proposed, which reshapes the output impedance of droop control inverter, and a 3 kW droop control inverter is designed for verified the effectiveness of the output impedance model and harmonics damping mothed.

Key words: Reactive compensation based on reactive power capacitor, droop control, islanded microgrid, impedance-based specifications, harmonic suppression

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