虚拟同步发电机下垂特性与控制模型阻尼系数的关系

Relationship Between Droop Characteristics and Damping Coefficient of Virtual Synchronous Generators

随着新能源应用的热潮,虚拟同步发电机技术发展迅速,它通过电力电子控制技术模拟同步发电机的下垂特性,通常其下垂特性与阻尼系数有关,但不同模型的虚拟同步发电机下垂特性与阻尼系数关系不尽相同.首先,分析了常见的三种虚拟同步发电机的频率-功率的小信号模型;然后,推导它们的下垂特性与阻尼系数的关系式;最后,搭建三种虚拟同步发电机的仿真模型,并通过单机并网运行以及双机并联运行两种不同的运行场景对虚拟同步发电机的下垂特性进行了仿真分析.仿真结果验证了三种虚拟同步发电机模型的下垂特性关系式,表明了虚拟同步发电机阻尼系数和下垂系数的关系以及它们对系统功率分配和系统频率的影响.

With the development of new energy application,VSG(virtual synchronous generator,VSG)technology develops rapidly.It imitates drooping characteristics of synchronous generator by using the power electronic control technology.Generally,VSG's drooping characteristics are related to damping coefficient,but varies from model to model.Firstly,three frequency-power small signal models of common VSG are analyzed.Then,the relations between their drooping characteristics and damping coefficient are derived.Finally,three VSG simulation and control models are established,and drooping characteristics of VSG are simulated and analyzed in two different operation scenarios:single generator grid-connected operation and double generators parallel operation.The simulation results verify the frequency-power drooping characteristics relations of the three VSG analysis models,and show the relationships between the damping coefficient and drooping coefficient of VSG,as well as their influences on the system power distribution and frequency.