Research On Sliding Mode And Active Disturbance Rejection Control Single-Inductor Dual-Output Buck Converter

Single-inductor dual-output(SIDO)Buck converter can convert one input voltage to two output voltages with only one inductor used.It has the advantages of small size and high voltage conversion efficiency,and has broad development prospect in the field of power supply for portable equipment.As the SIDO converter itself is a strongly coupled system,the output branches will inevitably have cross influence,which will affect the stability of the whole system.Therefore,it is of great significance to study how to improve the dynamic performance and reduce the cross influence of the output terminal.A sliding mode decoupling control strategy based on extended state observer(ESO)is proposed to solve the problems of severe cross-regulation and slow transient response in the output branch of SIDO Buck converter when the load sudden change.Firstly,the state equation and small signal model of SIDO Buck converter are obtained according to the time sequence relation of duty ratio of switch and the state average method.On this basis,the system model is transformed into the output voltage deviation model,and the main circuit ESO is designed to estimate the load disturbance.Combined with the interference estimation information,an improved adaptive reaching law back-stepping sliding mode controller for the main circuit switching tube is designed.Secondly,the branch system is fitted as an independent system according to the active disturbance rejection paradigm,in which the branch coupling term and external disturbance are regarded as the total disturbance,and the branch ESO is designed to estimate it.Combined with the total disturbance estimation information and sliding mode control algorithm,a sliding mode and active disturbance rejection controller(SM-ADRC)is constructed in the branch circuit switch.Finally,the stability of the proposed controller is proved based on the finite-time convergence theory and Lyapunov stability criterion.The theoretical and simulation results show that the proposed control strategy significantly reduces the cross-regulation between branches and improves the transient response speed of the system.In order to further solve the problems of poor stability and insufficient anti-disturbance ability of the output of the converter under uncertain perturbations such as circuit parameter perturbation and measurement noise,a control strategy of SIDO Buck converter based on improved SM-ADRC was proposed.Firstly,the traditional 3-order ESO is processed with increased order and filtering to improve the anti-disturbance performance of the system.The convergence and performance advantages of the improved ESO are analyzed by using frequency domain method.Secondly,the non-singular fast terminal sliding mode is combined with the improved fast double power reaching law to replace the traditional sliding mode control to improve the overall rapidity and robustness of the system.Finally,the stability of the proposed controller is proved based on the fixed time convergence theory.The theoretical and simulation results show that the proposed control strategy further improves the anti-disturbance ability and transient response speed of the system,and effectively improves the stability of the output terminal when the system circuit parameters are perturbated and high frequency noise is present.