HVRT Optimization Control Method Of Doubly Fed Induction Generator Based On Multiple Stages And Variational Damping

Energy is an important material basis for human survival and development,andwind power has a lot of advantages,just like abundant resources in renewable energy,good industrial foundation,strong economic competitiveness,and small environmental impact.In recent years,the application of Doubly-Fed Induction Generator(DFIG)has been widely accepted by the public for its ability to control the power transmission and variable speed constant frequency of the stator and rotor sideways power grids at the same time.However,when the voltage of the grid voltage is symmetrical,the over-current of the rotor and the over-voltage of the DC bus of the DFIG will not only threaten the safety of the core components of the wind turbine,but also cause the problem of economic loss caused by the large-area off-grid of the generator.People's attention.Compared to Low Voltage Ride Through(LVRT),High Voltage Ride Through(HVRT)technology has not received enough attention.Current control strategies for swells of grid voltage include crowbar,STATCOM,DVR,and addition of dummy resistors.However,these can no longer meet the requirements of the wind turbine to deal with a variety of grid faults.This paper takes the control system of the converter of the DFIG set as the research background,and mainly studies the control of the generator-side converter under the condition of symmetrical swell of the grid voltage.Increase the virtual resistance by adding a virtual resistance and changing the virtual resistance value in real time according to the dynamic changes of the rotor current and voltage.At the same time,the transitional process of DFIG is divided into two phases to change the relationship between the virtual damping and current and voltage,so as to realize the system's non-static adjustment function.This paper starts with the dynamic mathematical modeling and analysis of the doubly-fed wind power generator,and establishes a 2MW DFIG grid-connected system model based on the stator voltage vector control method,and compares the steady-state mathematical model of the doubly-fed generator.And the dynamic mathematical model points out that the establishment of a dynamic mathematical model is more conducive to the analysis of the transient transition process of the wind turbine under the sudden rise of the grid voltage.Then based on the theoretical analysis of traditional PI control strategy on the aircraft side,based on the existing virtual resistance control strategy,a multi-stage dynamic damping control strategy based on variable universe fuzzy logic control is proposed,and the transition process is divided into two phases.Applying the relationship between the rotor voltage and current and the virtual damping with two kinds of intervention time.Finally,through the establishment of a dynamic simulation model,verify the effectiveness of the control strategy.