规模化新能源入网逆变器的谐振机理与对策研究

项目名称： 规模化新能源入网逆变器的谐振机理与对策研究

项目编号： No.51207024

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 电气科学与工程学科

项目作者： 肖华锋

作者单位： 东南大学

项目金额： 25万元

中文摘要： 大规模电压源型并网逆变器在电网公共端（PCC）并联易引起谐振，导致并机失败和恶化电流质量。规模化并网逆变器的谐振机理迄今还未见报道，拟建立规模化并网系统的线性方程，采用特征值分析法分析该谐振特性。本项目组在前期研究中发现PCC多机并网逆变器的进网电流中谐振电流的频次、幅值和频率分布范围是时变的，拟采用对各逆变器支路的谐振电流成分进行闭环反馈再分别作用到各支路逆变器的控制回路中，通过逆变桥臂产生谐振电压作用到谐振网络上抑制该支路的谐振电流。为实现这一设想，本课题采用复小波变换来分解出谐振电流的相位和频率信息，再利用变频旋转坐标变换将该频次的谐振电流成分变换为直流分量，从而在逆变器的旋转PI控制器闭环作用下实现无静差地消除该动态出现的谐振电流，待有新的谐振电流成分出现时再启动该闭环过程完成对谐振电流的实时消除。本课题将从新的视角揭示规模化并网系统的谐振机理，并为谐振电流抑制提供新的思路和方法。

中文关键词： 并网逆变器；谐振；小波变换；软开关；

英文摘要： Mass voltage source grid-connected inverter paralleling with Point of Common Coupling will lead to resonant, which results in grid-in failure of inverter and poor current quality. The resonant mechanism of the mass grid-connected inverter has not been reported so far, the proposal proposes to establish linear equations of the mass grid-connected system, and then the resonance mechanism will be analyzed by the means of eigenvalue analysis. The resonant characteristics, such as frequency, amplitude and distributing scope, are time-varying which was found by the team in the preliminary study. The idea, that the resonant current is fed into the close loop controller of the grid-connected inverter to produce resonant voltage by the inverter, and then the resonant voltage is added to the resonant network to restrict the resonant curret, is proposed in the proposal. In order to realize the idea, the phase and frequency of the resonant current are decomposed by complex wavelet transform, then the resonant current is transformed to DC component by variable rate rotating coordinate. The resonant current can be eliminated with zero steady-state error through the variable rate rotating PI controller. Above closed loop process will not be restarted until the new resonant current occurs. Along with the progress of the propo

英文关键词： Grid-connected inverter；resonant；wavelet transformation；wavelet transform；