基于动态均衡原理的并联VSG参数匹配方法

A Matching Method of Parallel VSG Based on the Principle of Dynamic Equilibrium

在微电网中,并联运行虚拟同步机(VSG)在实现多机功率精准分配的同时,能够根据需要向微电网提供可控的虚拟惯量和阻尼支撑。不同的转动惯量会导致不同的频率变化率,具有大惯性的VSG需要更长的时间来响应负载变化,而发电机间如果参数不匹配会引起动态功率环流和频率振荡,进而影响系统稳定性。此处重点讨论了VSG动态响应特性,并据此推导了惯量和阻尼系数这两个关键参数的匹配原则,以提高多机并联VSG的运行性能。除此之外,还介绍了一种基于改进阻尼项的控制策略,使容量不同的各个虚拟机能工作在相同的阻尼系数值从而减少运算。最后在Matlab/Simulink环境下进行仿真,并搭建了实验平台,验证了所提方法的准确性。

In the microgrid,parallel operation virtual synchronous generator(SVG)can provide the controlled virtual inertia and damp support to the microgrid,while realizing the precision distribution of the multi-machine power.Different rotational inertia can lead to different frequency change rates.The SVG with large inertia needs longer time to respond to the load change,and the dynamic power circulation and frequency oscillation will be caused by the parameter mismatch between the generators,which will affect the stability of the system.The dynamic response characteristics of the SVG are discussed,and the matching principle of the two key parameters,inertia and damp coefficient are derived in order to improve the performance of the multi-parallel VSG.In addition,a new control strategy based on the damp term is introduced,which makes the virtual functions with different capacity working in the same damp coefficient to reduce the operation.Finally,simulation is carried out under Matlab/Simulink environment,and the experimental platform is set up to verify the accuracy of the proposed method.