可控电流源型换流器功率解耦控制策略

Power Decoupling Control Strategy of Controllable Current Source Converter

可控电流源型换流器(current source converter,CSC)是高压直流输电技术重要研究方向,随着逆阻型IGCT器件的发展,推动其应用技术上已经可行。但由于其电流源特性,大部分研究主要考虑定直流电流策略,针对定直流电压下的功率控制策略研究较少,严重制约其工程化发展。该文首先建立可控CSC的数学模型,获得有功、无功的影响变量。接着,对电容电压的d-q轴分量进行解耦,提出换流器内环和外环控制策略。然后,以直流电压和调制比为约束条件,对换流器的功率运行范围进行分析。最后,搭建基于常规直流和可控电流源的混合输电系统,对所提的控制策略进行分析,重点对单位功率因数运行和定直流电压时策略下功率调节特性进行仿真分析,对CSC在单相接地故障下抵御换相失败能力和向孤岛系统送电进行仿真。研究结果表明:所提的功率控制策略,能够实现有功、无功的解耦控制,以及对功率的有效调节,具备抵御换相失败的能力。

The controllable current source converter(CSC)is considered to be an important research point of high voltage direct current(HVDC)technology.The development of reverse blocking integrated gate commutation thyristor(IGCT)promotes CSC application feasibly.However,due to its current source characteristics,most of the researches mainly adopt the constant DC current strategy,while the research on power control strategy under constant DC voltage is less,seriously restricting its engineering development.In this paper,the mathematical model of CSC is established,and the influence variables of active and reactive power are obtained.Then,the d-q axis component of the capacitor voltage is decoupled,and the inner loop and outer loop control strategies are proposed.After that,the power operation range of the CSC is analyzed with the constraints of DC voltage and modulation ratio.Finally,a hybrid transmission system based on conventional LCC and CSC is built,and the proposed control strategy is analyzed.The research indicates that the proposed power control strategy can decouple active power and reactive power,as well as obtain excellent power regulation effectiveness.