VSC-HVDC统一电磁暂态模型及其控制策略

Unified Electromagnetic Transient Model and Control Strategy for the Voltage Source Converter Based HVDC Transmission

为了更好的应用基于电压源换流器(VSC)的新型高压直流输电系统,发挥其技术优势,提出了VSC-HVDC统一电磁暂态模型并进行了其控制策略的研究。交流侧电磁暂态模型是基于d-q同步旋转坐标系下建立的;利用交流侧与直流侧瞬时有功功率相等的原理建立了直流侧电磁暂态模型,且该模型考虑了换流电抗器损耗等因素。利用前馈补偿法设计了解耦控制器以达到分别通过电流d轴和q轴分量来独立调节有功功率和无功功率的目的。利用PSCAD/EMTDC对利用VSC-HVDC连接两端的有源网络以及对无源网络的供电进行仿真试验的结果证明,提出的计算模型及控制策略准确、可靠,对于各种干扰有较好的响应速度和较高的精度。

This paper proposes a unified electromagnetic transient model and control strategy for the voltage source converter （VSC） based HVDC transmission. The electromagnetic transient model of the VSC AC-side in the synchronous d-q reference frame has been built; the DC side dynamics are formulated based on the principle of instantaneous power balance, the instantaneous power absorbed by three-phase series inductors is also considered. The developed models are used to design controllers, For the purpose of control active power and reactive power separately, a decoupled controller based on feed forward compensation method has been designed. The simulation tests realized by PSCAD/EMTDC that VSC-HVDC supplying passive network and connect active network have been adopted. The proposed control system produces the best transient performance; the simulation results verify the validity of the mathematical model and the feasibility of the control strategies.