The main circuit of the traditional single-phase cascade H-bridge rectifier is improved

the power decoupling arm is added

the mathematical model is established

and the voltage balance and ripple suppression strategies are studied. Firstly

the whole loop is controlled by double closed-loop

and the extraction scheme of fundamental signal is optimized by the second-order generalized integration method. Secondly

the power balance relationship of the system is derived

the primary relationship model of the grid-side current and the capacitance voltage squared is established

and the variable proportion link is introduced to effectively improve the robustness of the system to resist parameter changes. Then

the independent Buck-type active power decoupling control strategy is adopted

and the duty cycle of the decoupled bridge arm switch tube is distributed in real time by calculation

and an adaptive frequency selector is designed to separate the secondary ripple signal to realize the suppression of the secondary ripple voltage ripple of the DC bus. Finally

the experimental verification based on Matlab/Simulink software shows that the proposed method can effectively solve the problems of voltage balance and secondary ripple power suppression.