Research On Adaptive Backstepping Control And Dual Output Topology Of SWISS Rectifier

With a large number of power electronic equipment being connected to the power grid,problems such as harmonic and reactive power pollution also follow.In order to fundamentally suppress the harmonics of electric devices,Power Factor Correction(PFC)technology has gradually become a research hotspot.SWISS rectifier is a threephase step-down PFC topology circuit,which has the advantages of high efficiency,reliable topology and easy control.This thesis focuses on the research work of SWISS rectifier,and makes an in-depth study on the improvement of its nonlinear control strategy and topology.Firstly,the basic working principle of SWISS rectifier is analyzed from two aspects of PFC function and steady-state output characteristics.On this basis,the state space average model of SWISS rectifier is established,and then its equivalent circuit model is further analyzed and deduced,which lays the foundation for the subsequent research of control strategy and the improvement of topology.The working principle of SWISS rectifier is simulated and verified in Simulink.Secondly,aiming at the weak dynamic anti disturbance performance of PI controlled SWISS rectifier,based on the state equation of the equivalent circuit of SWISS rectifier and combined with the basic principle of Adaptive Backstepping control,an Adaptive Backstepping controller of SWISS rectifier with load as the system uncertain parameter is designed,and its stability is proved.The simulation results show that compared with the traditional double closed-loop PI control,the Adaptive Backstepping control SWISS rectifier has better steady-state output characteristics and dynamic response performance against sudden load disturbance.The correctness of the simulation results and the effectiveness of the Adaptive Backstepping control strategy are verified by experimental tests.Finally,in order to realize that the SWISS rectifier can output two DC voltages with different voltage levels at the same time,the Single-Inductance Multi-Output structure is applied to the rear stage of the SWISS rectifier.After reasonable improvement,the topology of the Single-Inductance Dual-Output SWISS rectifier is obtained,and its working principle is further studied and analyzed,and the equivalent circuit model is established.Aiming at the problem of Cross-Coupling Effect between two output branches of Single-Inductor Dual-Output structure,a small signal model of the equivalent circuit of Single-Inductor Dual-Output SWISS rectifier is established,and then the modulation difference / common mode voltage signal and current control mode can reduce the Cross-Coupling Effect are theoretically analyzed,so as to further improve the traditional double closed-loop PI control strategy of SWISS rectifier,The block diagram of differential-mode voltage mode common-mode current mode control strategy of Single-Inductor Dual-Output SWISS rectifier is obtained.The feasibility of Single-Inductor Dual-Output SWISS rectifier topology and the effectiveness of its control strategy are verified by simulation analysis and experimental test.