基于双机并联虚拟同步机系统的自适应控制策略研究

Research on adaptive control strategy based on two-machine parallel virtual synchronous machine system

近年来,为了使分布式发电系统呈现类似于同步发电机的特点,基于同步发电机机电暂态分析理论的虚拟同步发电机(Virtual Synchronous Generator,VSG)控制技术受到了世界各国学者的广泛关注。然而多并联VSG系统在并网和故障稳定的过渡过程中存在功率振荡及频率波动,对电力系统的动态响应和稳定性有负面影响。文章介绍了VSG控制策略,建立了两台VSG并联的小信号模型,分析振荡时系统变量的变化情况,并提出一种基于自适应前馈控制的双机并联VSG控制策略。通过角频率的变化自适应增加前馈量补偿系统的功率缺额,提高了系统的响应速度和功率分配精度,抑制系统频率波动和有功功率振荡,保证了系统的快速稳定和安全性。最后在Matlab/Simulink平台上建立了仿真模型,仿真结果证明了所提出控制策略的可行性和有效性。

In recent years,in order to make distributed power generation systems present similar characteristics to synchronous generators,the virtual synchronous generator(VSG)control technology based on the theory of electromechanical transient analysis of synchronous generators has attracted widespread attention from scholars around the world.However,the multi-parallel VSG group has power oscillations and frequency fluctuations during the transition process of grid connection and fault stabilization,which has a negative impact on the dynamic response and stability of the power system.This paper introduces the VSG control strategy,establishes a small signal model of two VSGs in parallel,analyzes the change of system variables during oscillation,and proposes a two-machine parallel VSG control strategy based on adaptive feed-forward control,which adaptively increases the feed-forward amount through the change of angular frequency to compensate the power shortage of the system,improves the response speed and power distribution accuracy of the system,suppresses the system frequency fluctuations and active power oscillations,and ensures the fast stability and safety of the system.Finally,a simulation model was established on the Matlab/Simulink platform,and the simulation results proved the feasibility and effectiveness of the proposed control strategy.