摘要
针对功率变化引起的逆变器并网稳定性波动问题,基于阻抗稳定性判据,以三相LCL型并网逆变器为例,考虑锁相环在系统中的影响,建立电流环控制的并网逆变器交流侧输出阻抗小信号模型,分析功率变化与系统稳定的交互影响。研究系统传输功率增大会导致系统稳定性变差的现象,提出引入直流端电流补偿控制策略,该方案提高了并网逆变器交流侧输出阻抗在低频段增益,增大了系统稳定裕度,有效地处理了功率因素导致的系统稳定性波动问题。同时,在响应速度方面,无论是稳态还是暂态,加入直流电流补偿后的变流器并网系统调节时间更短,响应更为迅速,调节时间只有原系统的30%左右。最后,搭建三相LCL型逆变器并网仿真系统,通过仿真验证了文中理论分析的正确性。
Aiming at the problem of grid-connected stability fluctuation of the inverter when power changes,the paper takes three-phase LCL-type grid-connected inverter considering the influence of phase-lock loop in the system as an example based on impedance stability criterion and establishes the output impedance small-signal model with grid-connected inverter controlled by current loop to analyze the interactive influence between power change and system stability.The DC-link proportional control compensation is introduced to research the situation that the increase of transmission power causes the deterioration of the system stability.The strategy effectively deals with the system stability caused by the power by improving the output impedance gain of the grid-connected inverter in the low frequency band to increase the system stability margin.Meanwhile,the grid-connected inverter system introduced the dc-link current compensation holds the shorter regulation time which only about 30%compared with the original system and faster response no matter in the steady state or the transient state in terms of the response speed.Finally,the three-phase LCL-type grid-connected inverter simulink platform was established to verify the correctness of the theoretical analysis.
作者
姜玉霞
田艳军
李永刚
JIANG Yuxia;TIAN Yanjun;LI Yonggang(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Baoding 071003,Heibei Province,China)
出处
《电网技术》
EI
CSCD
北大核心
2020年第2期646-654,共9页
Power System Technology
基金
国家自然科学基金项目(51707067)
中央高校基本科研任务费专项资金项目(2018QN070).
关键词
逆变器并网
阻抗稳定
功率影响
补偿控制
grid-connected inverter
impedance stability
power influence
compensation control
