具有暂态阻尼特性的虚拟同步发电机控制策略及无缝切换方法  

VSG Control Strategy With Transient Damping Term and Seamless Switching Control Method

作　　者：李新 刘国梁 杨苒晨 陈国柱[1] LI Xin;LIU Guoliang;YANG Ranchen;CHEN Guozhu(College of Electrical Engineering, Zhejiang University, Hangzhou 310027, Zhejiang Province, China)

机构地区：[1]浙江大学电气工程学院

出　　处：《电网技术》2018年第7期2081-2088,共8页Power System Technology

基　　金：国家自然科学基金资助项目(51177147)~~

摘　　要：针对常规二阶虚拟同步发电机（virtual synchronous generator,VSG）控制中存在的一次调频特性与传统阻尼特性相互影响的问题,提出了引入反映同步发电机阻尼绕组特性的暂态阻尼环节的解决方法,同时实现VSG对同步发电机暂态特性和稳态特性的模拟,建立了具有暂态阻尼特性的VSG控制的小信号动态模型,通过广义根轨迹法定性分析了VSG控制参数对系统稳定性的影响,并结合频域特性指标,利用主导极点法对控制参数进行定量设计。针对VSG并网过程中可能出现的电流冲击,提出了基于直接电压鉴相原理的预同步控制策略,实现无锁相环VSG控制在不同运行模式之间的无缝切换。最后,利用搭建的微电网仿真平台,验证了理论分析的正确性以及所提预同步方法的有效性。Aiming at coupling problem between primary frequency regulation（PFR） and damping term in traditional virtual synchronous generator（VSG）, a virtual transient damping term reflecting real characteristics of synchronous generator＇s（SG） damping winding is introduced to realize simulation of SG transient and steady-state characteristics without affecting frequency regulation. A VSG small signal dynamic model with transient damping term is established and investigated. Besides, influence of VSG control parameters on system stability is analyzed with the generalized root locus method, and the parameters are quantitatively designed using dominant pole analysis method. Aiming at the impact current that may occur in process of VSG grid-connection, a novel pre-synchronous control strategy based on direct-voltage phase discrimination principle is proposed to realize seamless switching between two operation modes of non-PLL（phase locked loop） VSG. Finally, correctness of theoretical analysis and effectiveness of the proposed pre-synchronization method are verified through a microgrid simulation platform.

关 键 词：微电网 虚拟同步发电机 小信号动态模型 暂态阻尼 频率调节 无缝切换 

分 类 号：TM46[电气工程—电器]