Research On The Control Strategy Of Similar Synchronizer For VSC Inverter

With the development of new energy technology,the power system will use more andmore power electronic equipment,and the application of power electronic equipment in the power system is mainly reflected in the converter.The converter is a power electronic equipment.The moment of inertia of power electronic equipment is small and the response process is fast.It seldom,even does not participates in the voltage and frequency regulation of power grid,and can not increase the damping of the micro grid with relatively poor stability.In this paper,a control strategy is proposed to make the grid connected inverter have the advantage of large rotational inertia like the synchronous generator,increase the damping of the inverter,and participate in the frequency modulation and voltage regulation of the power grid,so as to maintain the stability of the power system.Firstly,the inverter operation mechanism of VSC converter,the operation mechanism of grid connected VSC inverter and space vector modulation are studied.The operation mechanism of grid connected VSC inverter includes voltage directional control and voltage directional control with decoupling controller,and the simulation analysis is carried out.Secondly,the mathematical model of the speed regulating system and excitation system of the synchronous generator set is established,and the characteristics of the frequency modulation and voltage regulation of the synchronous generator set are analyzed.On this basis,the power frequency and reactive voltage regulation characteristics of the grid connected VSC inverter are virtual,and the simulation model of the synchronous machine control system is built under the environment of MATLAB /Simulink,which verifies that the designed control strategy can make the VSC inverter participate in the frequency modulation and voltage regulation of the power grid.Finally,using impedance method to get grid connected VSC inverter may cause power system oscillation.The grid connected VSC inverter model is established and the grid connected VSC inverter is lack of damping.The virtual inertia and damping characteristics of the grid connected VSC inverter are designed,the inertia and damping of the grid connected VSC inverter are increased,the static stability analysis of the synchronous VSC inverter like inverter is analyzed,the influence of the parameters on the stability of the system is analyzed.