Buck Type DC-DC Converter Design And The Study Of Control Method

In the development of producing,many electrical facilities are increasingly requiring the quality of switching power supply.As a nonlinear time-varying system,the control technology of switching power supplies is also constantly being concerned.In many nonlinear control theories,the sliding mode control theory can effectively make the system undisturbed in the face of internal variations and matched disturbances.Therefore,the sliding mode control method is commonly used in DC-DC converters.In this paper,one of the more commonly used step-down switching power supplies,namely type converters,is mainly involved.Emphasis is placed on how to use the observer technology to make the switching power supply have excellent dynamic and static quality under the sliding mode control method.First,the overall structure of the Buck converter and the role of the main components in the working process are explained.According to its working principle and process,a mathematical model is built on the circuit under the continuous condition of current.According to the obtained component parameters of the Buck converter,a mathematical model is obtained to analyze the characteristics of the mathematical model in the frequency domain.Next,the basic concept of sliding mode control theory is explained.Then,the sliding mode control theory is used to control the converter,and the traditional sliding mode control theory is insensitive to the mismatched disturbance in the Buck converter system.In order to overcome this problem,the extended state observer is proposed,and the unmatched disturbance in the system is estimated as the state variable,and the estimated value is added to the traditional sliding mode controller.Thus,the sliding mode control which can effectively compensate the external disturbance is designed.In view of improving the response speed of the converter to the disturbance,a non-singular terminal sliding mode control method for the finite time convergence of the Buck converter is proposed.The finite-time convergence disturbance observer is introduced to compensate for the insensitivity of the non-singular terminal sliding mode controller to the non-matching disturbance.The simulation model is also used to verify the final effect of the relevant control strategy.Then,from the perspective of saving hardware cost and increasing system reliability,considering the idea of using soft measurement technology,when designing the closed-loop controller,design an observer that estimates the inductor current,and obtain a sliding mode control method based on feedback current estimation.The stability of the observer and control algorithm is analyzed,and relevant simulation experiments are carried out.Finally,designing the hardware experiment platform.This paper introduces the composition,construction and debugging process of each module in Buck type DC-DC converter hardware.After the design,boarding and debugging,on the basis of the hardware platform,the program of the corresponding control algorithm is written and the experiment is verified.