谐波注入法在柔性直流电网工程中的应用

柔性直流电网技术的应用将是应对全球清洁能源大规模开发的有效技术手段。针对高压大容量柔性直流电网工程受制于电力电子器件自身的通流或关断能力导致电流安全裕度较小的问题,将谐波注入法应用于柔性直流电网工程。通过在正弦波调制的基础上注入3次谐波的方法,提高直流电压利用率,降低同等容量下电力电子器件的电流应力。本文基于张北四端柔性直流电网示范工程搭建RT-LAB实时数模混合仿真系统进行实验,结果表明所提方法具备工程应用推广价值,有利于推动高压大容量柔性直流电网的工程应用。

Application of Harmonic Injection Method to in Flexible DC Grid Project

The application of flexible DC grid technology will be an effective technical means to cope with the largescale development of global clean energy. A high-voltage and large-capacity flexible DC grid project is usually constrained by the current flow or shutdown capability of the power electronic device itself,resulting in a smaller current safety margin. To solve this problem,harmonic injection method is applied to the flexible DC grid project. By injecting the third harmonic wave to the sinusoidal modulation,the DC voltage utilization rate can be improved,thus reducing the current stress of the power electronic device under the same capacity. Based on the demonstration project of Zhangbei four-terminal flexible DC grid,an RT-LAB real-time digital-analog hybrid simulation system is built. Results show that the proposed method has values of engineering application,which is beneficial to the promotion of engineering applications of high-voltage and large-capacity flexible DC grid.