近似逆系统方法应用于HVDC的有源直流滤波器

谐波治理是高压直流(HVDC)输电的关键技术之一。文中分析了应用在HVDC直流侧的有源直流滤波器的工作原理，从跟踪控制的角度出发，选取谐波源电流作为检测对象，把补偿电流作为反馈信号，构建了基于近似逆系统控制的复合控制；在控制器实现中，提出了以滤波器组构建近似逆系统的方法。PSCAD仿真和样机实验结果验证，因避开了弱信号提取问题，加之近似逆系统控制的快速稳定性，有源直流滤波器系统稳定、滤波效果优良，为下一步工业实施奠定了基础。

THE ACTIVE DC FILTER BASED ON APPROXIMATE INVERSE SYSTEM CONTROL

Eliminating harmonics is one of the key technologies in high voltage direct current (HVDC) transmission systems. This paper analyzes the principle of the active DC filter (ADF) applied in the HVDC system. A composite control strategy, in which the harmonic source current and the compensation current are respectively measured as the compensation object and the feed back signal, is proposed. A filter bank is adopted to compose the approximate inverse system, which is the feed-forward controller in the composite control strategy. Both results of simulation based on PSCAD and experiment on a 30 kVA HVDC system validate that the proposed control system is stable and can eliminate the harmonics efficiently, because of the advantages of the approximate inverse system and the absence of the extraction of weak signal from noise. This work has laid foundation for developing industrial equipment in future.