Discontinuous Control Research And Implementation For Boost DC-DC Converter Based On State Machine Structure

The rapid development of power electronics technology has enabled power electronic devices to be used in large-scale applications in electronics,computers,and new energy generation.People have higher requirements for high quality power output.Traditional linear control method is difficult to guarantee high quality output of power in complex application scenarios.In recent years,more and more scholars have devoted themselves to the study of non-linear control of electronic power converters.Among them,Boost DC-DC converter is one of the most commonly used power electronic converters,it is a typical nonlinear time-varying system.In the continuous current mode,the small signal transfer function of the converter exhibits an undesired right half plane zero,the system has a non-minimum phase characteristic.System modeling,stability and performance control of the output voltage become the intersection of concerns in the control field.The traditional linear control method achieves better control effect only near the operating point.It's difficult to control.Based on the analysis of the domestic and international research status of Boost DC-DC converter,the advantages and disadvantages of the existing control method are compared.Aiming at the higher dynamic performance requirements of the converter,based on the ideal of second order sliding mode state machine controller,a finite state machine control method for Boost DC-DC converter is proposed.The proposed control method achieve no overshoot control and faster dynamic response speed of the output voltage,it also achieve better robustness under large load disturbances.The research and design work of this thesis are as follows:(1)Do research on the working principle of Boost DC-DC converter,establish phase plane with output voltage and inductance current.Analyze the phase trajectory of the converter under different modes.Obtained the optimized trajectory curve for output voltage control and the optimal switching point between modes.Calculate optimized mode switching conditions.(2)A Boost DC-DC converter finite state machine controller is designed.The structure and control principles of the state machine controller are introdeced.According to the optimized phase trajectory and mode switching conditions.Design the trigger condition for state switching.The dynamic performance of the controller is improved to realize fast and non-overshoot control of the starting process of output voltage.(3)Aiming the problem of the robustness under load disturbances,the calculation process of updated value of reference inductance current is deduced and the role of compensation values is analyzed.An improved state machine controller is proposed to achieve strong robustness under load disturbance.The paper builds a simulation model and a hardware experiment platform to verify the proposed discontinous control method.The design process of the control system is given.Compared with the existing algorithm,the simulation and experimental result indicate that the proposed discontinuous control method for Boost DC-DC converter based on state machine achieve good robustness of the system and fast dynamic response of the output voltage.The proposed control method is physically implemented simply,achieve fast output voltage control without overshoot and provide good robustness under load disturbance.