Research And Analysis Of Buck-Boost Circuit Applied In AC System

This paper focuses on the research of the characteristics of the Buck-boost basic circuit applied in the AC voltage system.At first, Buck-boost circuit is detailed analyzed and derived strictly in the theory, and on the base, the current of the inductance and the output voltage are analyzed elaborately. When the input voltage is the AC voltage with the nomal frequency , the two variable quantity are analyzed and some conclusions are concluded by means of equal length separation methods and introducing function methods and derivative -equation methods. And this is the basis of the next proceeding.How to vary the two variable quantity of the Buck-boost basic circuit on the high frequency switching and whether or not their varying laws are fit for their theoretical conclusion. This paper with the help of the M file and Simulink toolbox in the MATLAB simulate the Buck-boost circuit system dynamicly. The large amount of dynamic simulation figures given in this paper verified the correction of the results of theoretical analysis.High frequency switching technique is becoming more popular in the power electronics area, the high frequency power Transistors are applied in the Buck-boost type chopper system. The characteristics of power MOSFET and Insulated Gate Bipolar Transistors (IGBT),some new kinds of power swithing devices ,are deeply studied. The application techniques, especially their voltage-type driving circuit and driving modula are explored; In the meanwhile, this paper illustrates the fast recovery diode working in high frequency briefly.At last , this paper also design a small capacity Buck-boost type chopper system,pointing out the problems and difficultes of the AC modulation voltage system in the future.