基于滑窗DFT算法的新能源直流并网逆变器协调控制方法

Coordinated Control Method for New Energy Direct Current Grid Connected Inverters Based on Sliding Window DFT Algorithm

当前的并网逆变器协调控制结构一般设置为独立形式,整体协调控制效率较低,导致周期逆变器的畸变率增加,为此提出基于滑窗离散傅里叶变换(Discrete Fourier Transform,DFT)算法的新能源直流并网逆变器协调控制方法。根据现有的测定需求和标准,先进行畸变电流测定,采用多目标的方式提高整体的协调控制效率。设计多目标交叉协调控制结构,构建滑窗DFT测算并网逆变器协调控制模型,采用三相平衡控制实现逆变器协调控制处理。测试结果表明,与传统带输出LC滤波器辅助逆变器协调控制方法和传统光伏处理逆变器协调控制方法相比,本次设计的基于滑窗DFT算法的逆变器协调控制方法最终得出的周期逆变器畸变率均被控制在0.2%以下,大幅提升了变网逆变器的协调控制效率,控制针对性增强,具有较好的实际应用价值。

At present,the coordinated control structure of grid-connected inverter is generally set in an independent form,and the overall coordinated control efficiency is low,which leads to the increase of the distortion rate of periodic inverter.Therefore,a coordinated control method of new energy direct current grid-connected inverter based on the Discrete Fourier Transform(DFT)algorithm is proposed.According to the existing measurement requirements and standards,the distortion current is measured first,and the overall coordinated control efficiency is improved by multi-objective method.Design a multi-objective cross-coordinated control structure,build a coordinated control model of grid-connected inverter with sliding window DFT,and realize coordinated control of inverter with three-phase balance control.The test results show that,compared with the traditional coordinated control method of inverter assisted by LC filter with output and the traditional coordinated control method of photovoltaic inverter,the distortion rate of periodic inverter finally obtained by the coordinated control method of inverter based on sliding window DFT algorithm is controlled below 0.2%,which greatly improves the coordinated control efficiency of variable grid inverter,enhances the control pertinence,and has good practical application value.