虚拟同步直驱风机低频振荡机理分析及阻尼补偿控制OACSTPCD

Virtual synchronous generator(VSG)technology can effectively improve the voltage support ability of the power grid.However,it also introduces complex low-frequency oscillation(LFO)problems.At present,most of the LFO studies on traditional VSG ignore the DC-side and generator-side dynamics,which makes it difficult to accurately characterize the LFO characteristics of virtual synchronous direct-driven wind turbine generators.To deal with the above problems,a unified damping torque model considering both the generator-side dynamics and the DC voltage dynamics is established.By using the damping torque method,it is revealed that the negative damping torque produced by the rotor dynamics on the generator side is the main reason of the LFO for wind turbines.Then,the influence law of each link on the LFO characteristics of the wind turbine is analyzed.Furthermore,a damping compensation control is proposed to reduce the negative damping effect of the machine-side dynamics and effectively improve the stability of wind turbine generator grid-connected system under machine-side coupling.Finally,the applicability of the proposed control in multi-computer systems is briefly analyzed,and the cases studies based on the MATLAB/Simulink simulation are conducted to verify the accuracy of the theoretical analysis and the effectiveness of the proposed control.