Research On Buck Converter Based On Linear Feedback Control

Enter after twenty-first Century, switching power supply is widely used in computer,household appliances, industrial instrumentation control etc. Switching power supply has theadvantages of small volume, light weight, high efficiency, high power factor and highreliability, the switching power supply technology of modern power electronic devices, powertechnology and control technology of electrical discipline overlapping to form a newcomprehensive discipline, power conversion technology, through the transformation of power,to meet the use need.Firstly, this paper studies the basic switching power supply topology-Buck converter. Buckconverter with input DC voltage into a DC output voltage, and the output voltage is less thanthe input voltage, realized DC-DC buck converter. Analysis of Buck converter under steadystate current in the continuous conduction mode and current discontinuous conduction modeoperation principle and the voltage transmission characteristic, Analysis of Buck transformerinductance selection and current ripple, electric capacity choice and the output voltage ripplerelationship and is validated by the simulation.Secondly, using state space average method to establish Buck converter small signalmathematical model, through the Buck converter can determine the switching converter withvoltage, current and small signal transfer function, the equivalent circuit mode can understandthe physical process of switch converter. Switching converter input voltage perturbationtransient response by input voltage transfer function to undertake an analysis, for the outputload disturbance dynamic responds by switching converter output impedance for analysis, theestablishment of Buck converter the open-loop transfer function and the analysis of systemstability margin, the compensation network to improve the stability of switch converter anddynamic response, through the simulation to verify the proposed mathematical model iscorrect and effective.In view of the actual Buck converter input and output parameters of the requirements,design the filter inductor and capacitor, so as to meet the inductor current ripple and outputvoltage ripple requirements, put forward and establish Buck converter OrCAD simulationmodel, simulation results verify the filter induction and filter capacitor design correctly.Finally, in order to reduce the Buck converter input, output capacitor current ripple,improve the load changes resistance perturbation dynamic response speed, put forward andestablish Buck converter interleaving parallel OrCAD simulation model validation, staggeredparallel-connected Buck converters to improve converter efficiency, reducing the capacitanceof the output ripple is effective.