背靠背柔直的VSG控制策略及应用研究
摘要:大量的分布式电源并网会对电网运行的稳定性产生影响，为抑制220 kV电网的合环电流和提高供电可靠性，提出一种接入双端柔性直流背靠背装置的设计方案。利用背靠背柔性直流构建交直流混合电网，对柔性直流的控制策略进行研究。采用三相两电平拓扑结构的电压源换流器，基于电流内环控制的双环电流控制策略，内环采用基于Park变换的d/q轴解耦控制原理，外环采用下垂控制和虚拟同步发电机(virtual synchronous generator, VSG)控制两种方式，利用PSCAD搭建电路模型，研究分析在系统发生故障扰动时不同控制策略下有功功率、电流、直流电压等的波动及恢复情况。仿真结果验证了VSG控制策略的优越性：与传统的柔性直流控制策略相比，VSG在动态过程中具有了惯性和阻尼电网功率振荡的能力，可对电网提供频率支撑，能更好地为系统提供惯性，提高系统稳定性。
Abstract：With grid-connection of plenty of distributed generation, stability of grid operation will be affected, in order to restrain the closing current of 220 kV power grid and improve the reliability of the power supply, this paper presents double back-to-back voltage source converter based high voltage direct current transmission (VSC-HVDC) device, Using back-to-back VSC-HVDC sets up AC/DC hybrid network, and research on the control strategy of VSC-HVDC.The paper used voltage source converter with three-phase two-level topology and double-loop current control strategy based on current inner-loop control. The inner-loop used d/q axis decouple control principle based on Park transformation and the outer-loop used droop control and VSG control respectively. By building circuit model with PSCAD，analyze the fluctuation of active power, current and DC voltage with different control strategies when a fault occurs. The simulation result verified the superiority of virtual synchronous generator control strategy. Compared with traditional VSC-HVDC control strategy，the virtual synchronous generator control strategy has the ability of inertia and damping power oscillation in dynamic process and can provide frequency support for power grid. VSG can be better used to provide the inertia of the system and improve the stability of the system.
标题：背靠背柔直的VSG控制策略及应用研究
title:Application Study on VSG Control Strategy of Back-to-Back VSC-HVDC
作者：王奥, 常征, 艾欣, 邹丹, 王坤宇
authors:WANG Ao, CHANG Zheng, AI Xin, ZOU Dan, WANG Kunyu
关键词：背靠背柔性直流,交直流混合电网,直流电压下垂控制,虚拟同步发电机控制,
keywords:back-to-back voltage source converter based HVDC,AC/DC hybrid network,DC voltage droop control,virtual synchronous generator (VSG),
发表日期：2018-12-30
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