虚拟同步发电机的功率动态耦合机理及同步频率谐振抑制策略  

Power Dynamic Coupling Mechanism and Resonance Suppression of Synchronous Frequency for Virtual Synchronous Generators

作　　者：李武华[1] 王金华[1] 杨贺雅 顾云杰[1] 杨欢[1] 何湘宁[1] 

机构地区：[1]浙江大学电气工程学院,浙江省杭州市310027

出　　处：《中国电机工程学报》2017年第2期381-390,共10页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划(973计划)青年科学家专题项目(2014CB247400);国家自然科学基金项目(51490682);浙江省自然科学基金项目(LR16E070001)~~

摘　　要：随着新能源并网的增加,现有并网逆变器采用的直接电流控制无法有效跟踪电网电压。虚拟同步发电机(virtual synchronous generators,VSG)技术通过模拟同步发电机运行机制,改善了系统稳定性,成为解决分布式电源高渗透率问题的有效方案之一。然而,虚拟同步发电机存在同步频率谐振现象,容易引发功率振荡,导致系统不稳定。该文分析电磁磁链的动态过程;通过建立虚拟同步发电机的宽频域功率动态耦合模型,发现有功–无功的功率耦合效应会加剧同步频率谐振;基于同步频率谐振的产生机理,采用有源阻尼控制的策略能有效抑制该谐振问题。最后,通过搭建实验平台,验证虚拟同步发电机中的同步频率谐振现象、有功–无功动态耦合效应正确性及阻尼抑制策略的有效性。The virtual synchronous generator（VSG） is an effective solution for controlling voltage source converter（VSC） as synchronous generator when high-penetration renewable energy sources are integrated into the power system. However, VSGs suffer the inherent resonance at synchronous frequency, which may result in power oscillations and even deteriorate the system stability. The synchronous frequency resonance phenomenon was investigated by establishing the complex vector models of VSGs. Furthermore, it is revealed that the synchronous frequency resonance in VSG is induced by the electro-magnetic flux dynamics. Moreover, the dynamic coupling mechanism between the active and reactive power controllers is disclosed. The coupling effect accentuates the resonance phenomenon and reduces the stability margin of VSG system. According to the intrinsic reason for synchronous frequency resonance, the virtual electrical resistance was added to restrain the resonance at synchronous frequency without extra power loss. Finally, the effectiveness of the theoretical conclusions was verified experimentally.

关 键 词：虚拟同步发电机 电压源型换流器 功率动态耦合机理 有源阻尼 虚拟阻抗 

分 类 号：TM[电气工程]