Design Of Controller For Power Converter Based On Traditional And Second-order Sliding Mode Theory

With the development of society,the variety of electronic equipment is becoming more and more diversified,and the demand for power supply is also increasing daily.Switching power supply has been widely used because of its high efficiency,low energy consumption and stable performance.The realization of power conversion is the basis of switching power supply.Through the design of effective control method,the performances of power converter can be improved.The traditional linear PID controller in the power converter under large disturbance condition failed to obtain a satisfactory control performance.In order to obtain better control effect,many scholars devote themselves to the study of new control methods.In this paper,based on the use of sliding mode control theory,two nonlinear control method has been developed.At the same time,the theoretical feasibility analysis and specific realization steps of the above control methods are provided.The main contents of this paper are as follows:(1)The research of power converter and the application of sliding mode control in power converter have been introduced firstly.Then the main research contents of this research are clarified.(2)The power converter modeling has been completed and then the hardware and software platform has been designed.Firstly,the Buck converter is taken as an example to analyze the principle of the system,and the practical mathematical model is established by considering the disturbance factors of the system.Then the hardware circuit board module of Buck converter has been designed,Further more,the actual circuit is connected with the LabVIEW software through the data acquisition card,and the program is written by LabVIEW to realize the closed-loop control platform.Finally,the PID control algorithm has taken as an example to verify the feasibility of the hardware and software experimental platform.(3)A composite control algorithm for Buck converter based on first-order sliding mode and disturbance observer has been designed.Firstly,the disturbance observation technique has been used to observe the disturbance in the derivative of the voltage deviation.The sliding surface with the compensation term has been designed,and then the controller has been designed by using reaching law.Considering the chattering problem of the first-order sliding mode,the quasi-sliding mode method has been used to improve the controller,and then the disturbance observation technique is introduced again to compensate the lumped disturbance in the system.Finally the effectiveness of the control method is verified by simulation and experiment.(4)A buck converter control algorithm based on second-order sliding mode has been designed.Firstly,the second-order sliding mode control technique is used to design the discontinuous second-order sliding mode controller,then the actual controller has been taken as the integral of the discontinuous controller,and thus the chattering problem can be avoided.The finite time stability of the control method is proved by Lyapunov stability theorem.Finally,the simulation and experiment method is used to verify the robustness of the control method and avoid the chattering problem of the sliding mode.(5)The basic research contents of this study have been summarized,meanwhile the defects of the proposed methods and the future research have also been discussed.