基于干扰对消原理设计应用于高压直流系统的有源直流滤波器

有源直流滤波器是高压直流输电系统谐波抑制的主要装置之一.针对现有控制方案的缺点,提出一种基于干扰对消原理的控制策略.新的控制策略中,选取传输线电流作为反馈信号,把整流站谐波电流视为系统干扰源,由多个滤波器构建补偿控制器去消除系统干扰.在不改变系统特征方程的条件下,可以有效地改善系统稳态误差,并进一步简化主控制器的设计,从而提高系统的响应速度,增加系统稳定裕量.仿真和实验的结果验证了该控制方案的优越性.

Interference Canceller Based ADF Applied in HVDC System

Active DC Filter(ADF)is one of filtering equipment applied in HVDC. A novel control strategy based on an interference canceller is proposed here in order to overcome the disadvantages of those existing in control strategies of ADF. In novel control strategy, the transmission line harmonic current is measured as the feedback signals, while the converter station harmonic current is measured as the system interference. The interference canceller is introduced to improve interference rejection and ensure the stable performance of system without change of characteristic equation. At the same time, the robustness of system can be improved and the response time is decreased, because the design of main controller is simplified. Furthermore, The design rule of interference canceller is detailed in this paper. The canceller is composed of several filter banks including band-pass filters, amplifier filters and phase-shifted filters and all that are designed for main characteristic harmonics. The Bode-diagram shows that the impedance-characteristic performance of the canceller is approximate to the that of the passive filter. A lot of simulations based on PSCAD/EMTDC and experiments based on a 30kVA lab system had been carried out, and the results can validate the proposed control strategy.