变压器双向磁化类变换器工作原理的讲解方法

The Way to Explain the Operation Principle of Symmetry Magneting Transformer in Power Electronics Course

在电力电子技术课程中,推挽式、半桥式和全桥式隔离型变换器电路属一类变压器磁芯双向磁化的基本电路,在实际中得到广泛的应用。如何给学生解释清楚铁心双向对称磁化的原理是一个教学难点。本文以推挽电路为例分析了铁心双向对称磁化工作机理。从带磁复位绕组的单端正激变换器的变压器铁心磁化工作原理出发,将推挽变换器看成是两个带磁复位绕组的单端正激变换器的组合。并从空载时占空比小于四分之一情况出发,循序渐进地全面细致地分析了各种负载情况下的工作原理,这种讲解思路严谨且易于被学生理解和接受。

In power electronics, push-pull converter, half-bridge and full-bridge isolation converter, in which the magnetic cores of transformer are magnetized bidirectionally which lead to high utility ratio are basic and important circuits. However, in the teaching of this course how to unpuzzle the principle of the magnetic core＇s symmetrically bidirectional magnetization is right difficulty. In this paper, the operation principle of transformer is analyzed with exemplifying the push-pull circuit. Firstly, the fundamental operation principium about the magnetization of magnetic core in forward converter with reset winding is introdced, and the push-pull converter is the combination of two forward converters with reset winding in fact. In addition, the analysis of principle under kinds of loads will be outspreaded in proper sequence basing on the situation that the duty cycle is less than a quarter when unload. The explaining way proposed in this paper is not only preciseness but also prone to catch on and take in for students.