基于虚拟同步发电机的逆变电源控制策略研究

针对采用常规下垂控制方法的逆变电源存在稳定时电压和频率的偏移,不能完全满足电网运行要求的问题,采用了一种新的逆变电源控制方法即虚拟同步发电机(VSG)控制策略。建立了虚拟同步发电机的模型,参考同步发电机控制理论,重点设计了功频控制器和励磁控制器,搭建了以大容量汽轮发电机模拟电网的逆变器并网发电系统。通过Matlab/Simulink仿真验证了虚拟同步发电机中转动惯量的作用和虚拟同步发电机的并网调节特性,仿真结果表明,基于虚拟同步发电机的逆变电源在外特性上近似等效为一个同步发电机,具有良好的调频调压性能,能很好地适应电网的运行要求。

Research on Control Strategies of Inverters Based on Virtual Synchronous Generator

In view of the conventional droop control method of inverter existing voltage and frequency offset in the steady state, cannot fully meet the requirements of the grid operation, a new control strategy of inverters called virtual synchronous generator(VSG) is adopted. A virtual synchronous generator model is established, focusing on the design of the power frequency controller and excitation controller based on synchronous generator control theory. An inverter grid-connected system which uses a large capacity steam turbine generator to simulate grid is built. The role of the rotational inertia and the grid-connected regulation characteristics of virtual synchronous generator are verified through Matlab / Simulink simulation. The results show that, the inverter based on virtual synchronous generator control strategy is approximately equivalent to a synchronous generator in external characteristics, has advantages in modulating frequency and voltage and is conductive to grid operation.