Research On A New DC/DC Boost Converter

In today’s electronic equipment,the demand for DC voltage conversion is almost everywhere.For example,in the development and use of new energy,because the voltage that fuel cells or solar cells can provide is usually low,in the actual use of electrical equipment will inevitably encounter the problem of boosting voltage.In addition,boost converter is widely used in switching power supply,power factor correction and other scenarios.The power converter of switching power supply is the key part in the research of switching power supply.It’s mathematical modeling,stability analysis and controller design have always been the focus of circuit electronics research.Especially in recent years,with the introduction of various modes of switching power supply control chips by major chip manufacturers,the reliability,flexibility and practicability of switching power supply are greatly improved,and switching power supply is used more and more in various scenarios.In this thesis,a boost topology based on voltage lifting technology is studied,and this boost circuit is used in the driving power supply of piezoelectric ceramics,in order to improve the common problems of large loss,large volume and low power caused by linear power supply driving mode in the current market.Therefore,this thesis will study a high gain boost circuit based on voltage lifting technology.The goal of the design is to develop a 28 V input voltage to 150 V output,and the regulating time is 0.1s The research contents of the internal switching power supply mainly include:(1)This thesis analyzes the working principle of step-up switching power supply,and puts forward the problems faced by step-up switching power supply in the limit of step-up ratio.In order to improve the boost ratio of boost circuit,there are many structures of high gain switch boost circuit,including traditional boost chopper circuit,boost converter with multi-stage cascade structure,boost converter with switch capacitor structure,boost converter with input parallel output series,etc.After comparing the advantages and disadvantages of various boost circuit topologies,we choose the same high gain boost circuit based on voltage lifting technology as the power part of boost switching power supply.(2)The mathematical model of a high gain boost circuit is established by the state space average method.The process of the modeling method is as follows: firstly,the equivalent circuit of the boost circuit when the switch is on or off is analyzed,and then the mathematical expression of the key state quantity and output quantity is analyzed according to the two equivalent circuits.Its specific expression is based on the characteristics of the circuit and the analysis of capacitance and inductance.Finally,according to the weighted average of the switch states,the mathematical expressions of the switching power supply in the whole switching cycle are obtained.(3)On the basis of the mathematical model,the further analysis and Research on the boost circuit are carried out.Firstly,the mathematical model of the boost circuit working in peak current mode is simplified by establishing equivalent power level,and the multi input single output system is simplified as single input single output system.After that,the control circuit of peak current mode is designed by using this simplified model,and the circuit of the designed peak current control mode is simulated in MATLAB Simulink.In order to compare the peak current mode with the average current mode,the root locus method is also used to design the circuit of the average current mode,and the specific circuit of the protection and compensation link is designed.Finally,the circuit of the average current mode is simulated in PSIM and compared with the output of the circuit in the peak current mode.The output of the average current mode under the rated load is more stable,the response time is faster,the ripple is 40 mv,and the adjustment time is: 0.08 s,and the peak current mode ripple under rated load is 90 m V,and the regulating time is: 0.1s.However,when the load or the input power supply is disturbed,the peak current mode can suppress the disturbance more obviously.The ripple increases from 90 m V to 110 m V,while the average current mode increases to 0.7V.