基于模糊辅助控制的虚拟同步发电机并网研究

Research on virtual synchronous generator grid connection based on fuzzy auxiliary control

为了提高新能源并网抗扰动性能和频率动态调节能力,解决其并网过程中惯性缺失问题,研究发现虚拟同步发电机(VSG)控制策略在一定程度上可改善系统的功频特性,但缺乏对系统各暂态性能的共同调节。基于此,提出一种基于虚拟惯量与阻尼的新型模糊辅助控制策略。首先,建立虚拟同步发电机数学模型,分析虚拟惯量与虚拟阻尼对VSG输出功率的影响;设计相对应模糊控制规则,以降低系统的频率与功率偏差,提高电网的稳定性;最后,利用Matlab/Simulink仿真软件,对比自适应VSG控制和VSG模糊虚拟惯量控制两种控制策略,验证了所提策略可减小功率与频率的超调量,并有效改善了系统在并网过程中的暂态特性。

In order to improve the anti-disturbance performance and dynamic frequency adjustment ability of new energy grid connection,and solve the problem of lack of inertia during the process of grid connection,the study found that the virtual synchronous generator(VSG)control strategy can improve the power-frequency characteristics of the system to a certain extent,but lacks of joint adjustment of the transient performance of the system.On the basis of this,a new fuzzy auxiliary control strategy based on virtual inertia and damping is proposed.A virtual synchronous generator mathematical model is established.The effect of virtual inertia and virtual damping on the output power of the VSG is analyzed.The corresponding fuzzy control rules are designed to reduce the frequency and power deviation of the system,so as to improve the stability of the power grid.Finally,the two control strategies of adaptive VSG control and VSG fuzzy virtual inertia control are compared by Matlab/Simulink.It has been verified that the proposed strategy can reduce the overshoot of the power and frequency,and effectively improve the transient performance of the system in the process of grid connection.