新能源并网变换器同步稳定分析及控制策略OA

With the growing penetration of renewable energy power generation in the power system,the synchronization stability problem of voltage source converter(VSC)has become increasingly prominent under fault conditions.To further reveal the synchronous instability mechanism of the VSC during faults and enhance its synchronous stability,this paper studies in detail the synchronous stability problem of VSC during the low voltage ride-through(LVRT).Firstly,referring to the synchronous generator(SG),the equivalent rotor swing equation of VSC is established.Consequently,the large/small disturbances synchronization stability mechanism of VSC can be revealed under a severe symmetric grid fault.The analysis results clearly show that the deep voltage sag,improper current instructions,large transmission line impedance,and inappropriate controller parameters would all deteriorate the synchronization stability of VSC.Furthermore,a synchronization stability improvement control strategy based on automatic voltage regulation is proposed,which can not only generate additional virtual torque,and virtual damping to enhance the the large disturbance synchronization stability of VSC,but also increase the damping ratio to improve the small disturbance synchronization stability of VSC.Finally,the simulation results validate the validity of the proposed strategy.