多台并网逆变器并联运行低频谐振及负阻尼补偿方法研究  

Research on low-frequency resonance of multi-parallel grid-connected inverters and negative damping compensation method

作　　者：李小强[1] 王凯[1] 耿乙文[1] 伍小杰[1] 

机构地区：[1]中国矿业大学信息与电气工程学院,江苏徐州221116

出　　处：《电测与仪表》2015年第9期70-76,95,共8页Electrical Measurement & Instrumentation

基　　金：江苏省普通高校研究生科研创新计划项目(CXZZ13_0929)

摘　　要：从导纳的角度研究了多台并网逆变器并联运行的低频谐振问题。由于软件锁相环的影响,基于LCL滤波的并网逆变器输出导纳在低频区域存在负阻尼,而随着并联逆变器台数的增加,并网逆变器和感性电网阻抗所构成的阻抗网络的谐振频率降低,当位于低频区域时,输出导纳的负阻尼特性容易导致系统不稳定。为了消除负阻尼,抑制低频谐振,在电流指令值中引入电网电压前馈,并在对输出导纳其它频率特性影响最小的基础上,推导出前馈补偿系数的最小理论值。最后,实验结果验证了理论分析的正确性以及负阻尼补偿方法的有效性。This paper investigates the low-frequency resonance issue of multi-parallel grid-connected inverters from the perspective of admittance .Due to the effect of software phase-locked-loop （ SPLL） , the output admittance of grid-con-nected inverters with an LCL filter contains the negative damping at the low-frequency region .And with the number of parallel inverters increasing , the resonant frequency of the impedance network composed of grid-connected inverters and inductive grid impedance is decreased .When located at the low-frequency region , the negative damping of the output admittance will easily lead to system instability .In order to eliminate the negative damping and damp the reso-nance, the feed-forward of grid voltage is introduced to the current command value .Furthermore, the minimum theo-retical value of feed-forward compensation coefficient is derived on the basis of minimum effects on other frequency characteristic of the output admittance .Finally, the experimental results verify the correctness of theory analysis and the effectiveness of negative damping compensation method .

关 键 词：并网逆变器 输出导纳 软件锁相环 负阻尼 低频谐振 

分 类 号：TM464[电气工程—电器]