考虑超调的虚拟同步发电机暂态功率振荡抑制策略

Transient Power Oscillation Suppression Strategy of Virtual Synchronous Generator Considering Overshoot

虚拟同步发电机(VSG)在有功指令和电网频率扰动下存在输出有功暂态振荡和稳态偏差的问题。控制中增加暂态阻尼环节可以抑制振荡、避免稳态偏差,但存在较大超调问题。通过建立VSG在2种扰动下的有功闭环小信号模型,依据根轨迹分析振荡抑制效果,进一步结合零点分析超调,得到暂态阻尼策略下VSG超调的原因和特性,并提出2种基于有功暂态补偿的VSG功率振荡抑制策略:暂态前馈补偿和暂态反馈补偿。2种改进策略均可以提升系统的暂态阻尼,有效抑制VSG有功振荡,既不会增大稳态偏差,又能大大减小超调。通过MATLAB/Simulink仿真及StarSim硬件在环半实物实验验证了所提策略的正确性和有效性。

Virtual synchronous generator(VSG)has the problems of the output active power transient oscillation and steady-state deviation under active power command and grid frequency disturbance.Adding the transient damping link in the control can suppress the oscillation and avoid the steady-state deviation,but there is a high overshoot problem.By establishing the active closed-loop small signal model of VSG under two disturbances,the oscillation suppression effect is analyzed according to the root locus.Furthermore,combined with the zero point analysis of overshoot,the causes and characteristics of VSG overshoot with transient damping strategy are obtained,and two VSG power oscillation suppression strategies based on active power transient compensation are proposed,i.e.,transient feedforward compensation and transient feedback compensation.Both the two improved strategies can improve the transient damping of the system and effectively suppress the VSG active power oscillation,which will not increase the steady-state deviation and can greatly reduce the overshoot.The correctness and effectiveness of the proposed strategy are verified by MATLAB/Simulink simulation and StarSim hardware-in-the-loop experiment.