电网谐波产生高电压工况下三电平变流器的谐波电流抑制

摘要

介绍了中点钳位型三电平变流器的数学模型,分析了电网谐波条件下变流器谐波电流产生的原理. 提出一种新型电网谐波下三电平变流器的谐波电流抑制方案,该方案采用α-β正负序解耦计算电网电压基波前馈项,采用d-q正负序解耦进行电流闭环控制,并引入电网电压谐波经P调节器作为电压前馈项叠加至基波调制波进行谐波电流抑制. Matlab仿真表明,所提控制策略比传统的d-q正负序解耦控制,明显改善了谐波电流含量.%The mathematical model of three-level neutral-point-clamped converter is introduced, and the theory of harmon-ic current generated by harmonic grid voltage is analyzed.A novel harmonic current suppression strategy is proposed.The strategy useα-βpositive and negative sequence decoupling to calculate the fundamental component of grid voltage, use d-q positive and negative sequence decoupling to control current loop, and use harmonic grid voltage through P controller to sup-press harmonic current.The feasibility of this strategy is analyzed by Matlab simulation.Compared with the traditional d-q decoupling control, the simulation of the proposed control strategy significantly improves the harmonic current.