虚拟同步发电机与同步发电机动态特性的比较分析

针对虚拟同步发电机(VSG)与同步发电机并联混合供电配合困难问题,需明确VSG与同步发电机动态性能上的差异。首先介绍了VSG控制原理,并建立数学模型,同时在数学推导的基础上,从惯量功率和频率动态响应两方面对逆变器与同步发电机动态性能进行分析。针对动态特性的不同,根据频率响应时间及功率震荡程度重新整定VSG控制参数,以减少两者动态特性差异。最后通过仿真分析指出,VSG在不同运行工况下所需要的转动惯量不同,通过调整控制参数使VSG控制的逆变器动态特性更加接近同步发电机的,甚至优于同步发电机的。

A Comparative Analysis of Dynamic Characteristics Between Virtual Synchronous Generators and Synchronous Generators

In view of the difficulty found in the hybrid power supply of the virtual synchronous generators (VSG) and the synchronous generators, it is necessary to clarify the differences between the dynamic performance of the VSG and the synchronous generators. Firstly, the control principle of VSG has been introduced, with the mathematical model established. Meanwhile, on the basis of mathematical derivation, an analysis has been made of the dynamic performance of inverters and synchronous generators from two aspects of inertia power and frequency dynamic response. According to the different dynamic characteristics, the VSG control parameters are re-tuned according to the frequency response time and power oscillation degree, thus reducing the dynamic characteristics difference between the two. Finally, it is pointed out that the moment of inertia required by VSG is different under different operating conditions. By adjusting the control parameters, the dynamic characteristics of VSG controlled inverters are closer to that of synchronous motors, even characterized with a better performance than that of the synchronous generators.