Research On Control Strategy Of Phase-shifted ZVS Full-bridge Converter

DC-DC converter in the power conversion field has a wide range of applications.Generally,power conversion of conventional DC-DC converter is accomplished using analog circuitry.However,in recent years,due to the continuous development of digital signal processing technology and the speed of microprocessors/microcontrollers and digital signal processor continue to improve,more and more power converter began to switch to digital control of the power converter.Compared to analog control,digital control has many advantages.First,the digital control can complete more complex control strategies,and secondly,the use of digital control can improve system reliability and flexibility,First,the digital control can complete more complex control strategies,and secondly,the use of digital control can improve the reliability and flexibility of the system.At the same time,the power converter will be toward the intelligent direction of development.And it can greatly shorten the product development cycle.This paper reviews the DC-DC control technology background and research status.This paper reviews the DC-DC control technology background and research status.Describe the current feedback and voltage feedback two kinds of linear control mode,and analyzes their advantages and disadvantages.The paper also introduces several nonlinear control strategy one cycle control and fuzzy control,and analyzes their respective advantages and disadvantages.Finally,the paper describes the sliding mode control algorithm.Because of its robustness,fast dynamic response,anti-interference ability,so that the sliding mode control has been widely used.In this paper,phase-shifted ZVS full-bridge converter for the study,describes the working principle of the circuit and its corresponding operating modes.The existence of the duty cycle of the circuit loss problems are discussed in detail,and gives the conditions of topology before and after the bridge arm realize ZVS.For circuit duty cycle loss problem,the paper introduces the establishment of method of small-signal circuit model,and analyzed by the transfer function,gives the corresponding state space equation.The paper simply introduces the sliding mode control,establishment of phase-shifted full-bridge ZVS converter based on sliding mode control,and given the three conditions of sliding mode control.According to the sliding coefficient of second order sliding mode controller is difficult to select the issues,the paper uses of the sliding surface equation into second-equation,through the relationship of system parameters and bandwidth and the conditions of critically damped determine the final sliding coefficient.By Matlab simulation platform,verify the sliding mode control used in the ZVS converter,in anti-interference ability,robustness and speed of response is excellent.Finally,we designed and built a F28033 DSP-based phase-shifted full-bridge ZVS converter prototype.Prototype design includes a power circuit design,control circuit hardware design and software design of DSP in three parts.Prototype design was slow to start the test,the soft switch test,steady state testing,dynamic testing and efficiency testing.From a performance analysis of the sliding mode control can achieve robustness,excellent anti-jamming capability and fast dynamic response speed.