Research On STATCOM Control Strategy Based On LCL Filter

A generation of power electronic devices,a generation of power electronic technology.With the development of high-frequency switches and microcomputer technology,the control accuracy has been improved,and new control strategies have been continuously proposed,making the control effect more excellent.However,the use of high-frequency switches will deliver reactive power and harmonics to the power grid,and complex control strategies using electrical equipment load characteristics become complicated,seriously affecting the power quality of the power grid.The STATCOM has a fast response speed and is easy to expand to high voltage,and has been widely studied.Aiming at the difficulty of grid voltage differentiation,linear auto disturbance rejection is used to control STATCOM filtered by LCL,bypassing the differential treatment of grid voltage.First,the mathematical model of STATCOM with LCL filtering is established to determine the relevant parameters of LCL and STATCOM.Second,after analyzing the characteristics of auto-interference and linear auto-interference,linear auto-interference is selected as the controller,and the relevant parameters are designed.;Then,for the problem of overshoot in the linear auto-disturbance control process,add a transition process to solve the problem;Finally,the parameters of the linear auto-disturbance rejection are optimized using particle swarm optimization.The STATCOM DC side voltage balance control strategy is analyzed and optimized.First,for the overall voltage control,when PI and linear auto-interference rejection cascade control,the overshoot characteristic of PI is transferred to linear auto-interference rejection,the transition process is used to reconstruct the total voltage command value to solve the problem;second,for In the phase-to-phase voltage balance control of zero-sequence voltage,the traditional zero-sequence voltage is used to solve complex problems.A method of solving zero-sequence voltage based on virtual power is used to simplify the process of solving the zero-sequence voltage command.Combining voltage control and phase-in-phase voltage control,a three-level balancing control strategy for DC side voltage is designed,so that STATCOM does not need to switch the control strategy in different stages during the charging stage,zero output current stage and reactive power compensation,and does not increase the system Complexity.