Research On Steady Flow Control Strategy Of High Current Rectification System

As a power supply system for large-scale factories,high-current rectification systems have received increasing attention in terms of rectification accuracy and stability as production scales have expanded.In this paper,the 400kA electrolysis power supply steady flow control system is taken as the research object.In order to improve the dynamic performance of the controller,the following work is mainly carried out:Firstly,the mathematical model of the rectification system combining phase shifting transformer,rectifier transformer,rectifier diode and self-saturated reactor is established,and the second-order state equation of the system is obtained to lay the foundation for the design of the subsequent steady current controller.Aiming at the problem that the traditional PID controller can easily amplify the noise and control precision during the tracking signal process,combined with the speed control integrated function and the fal function to design the tracking link,the noise amplification is effectively suppressed;on this basis,the disturbance compensation link is introduced.The feedback control law is improved,and the nonlinear self-disturbance stabilization current controller is designed to further improve the controller performance.Secondly,for the problem of too many controller parameters,the linear extended state observer is used to design the linear auto-disturbance controller,and the bandwidth method is used to select its parameters,which greatly reduces the number of parameters.In order to compensate for the control performance degradation caused by the controller changing from nonlinear to linear,combined with the improved exponential approach law sliding mode control algorithm,a rectification controller based on sliding mode auto-disturbance recombination algorithm is designed.Finally,according to the above theory and the proposed control method,the controller is programmed by S-Function,the rectifier system simulation model is built on the MATLAB/Simulink simulation platform,and relevant simulation experiments are carried out under different working conditions.The results show that the improved rectifier controller has strong control robustness and fast response,which proves the effectiveness of the proposed control strategy.