Analysis of a Resonant Converter Controlled by Triac
Analytical and experimental considerations in the constant voltage transformer are presented. The constant voltage transformer consists of a linear reactor, a linear transformer, a capacitor, a triac, and a feedback circuit. The feedback circuit is used to make the triac fire precisely at any angle from zero to ¿/2 so as to keep output voltage constant. An analysis of this circuit is presented in which the higher harmonic currents generated in the triac are neglected and the output voltage is assumed to be kept constant. The experimental results agree well with the theoretical value with respect to the load characteristic, the voltage characteristic, the power factor, and the jumping phenomenon.
Analysis of the ferroresonant transformer with a rectified output in the low-line-voltage minimum-line-frequency full-load condition
Most previous analyses of the ferroresonant transformer address the unrectified-output AC-load case, and do not include some or all of the important loss mechanisms. The analysis reported in this paper addresses the rectified-output DC-load case and includes the stray losses. The low-line-voltage minimum-line-frequency full-load condition is the focus of this analysis because it is the worst-case condition for supplying power to the load. Assumptions about the operation of the transformer in this worst-case condition lead to a simplified equivalent circuit. Given equivalent-circuit element values, a special-purpose time-domain computer simulation analyzes transformer performance in the periodic steady-state condition. This analysis technique is used to find equivalent-circuit element values for which the transformer winding currents are a minimum and the input power factor and conversion efficiency are at a maximum. >
Wiki, a New Way to Produce Accessible Documents
Adapting complex documents to make them accessible for print disabled persons is an iterative process which involves various skills and requires the intervention of several people. Collaborative approaches are well suited, especially those based on Wikis which are now widely used to edit contents on the Web. A Wiki offers useful features to overcome some of the difficulties encountered when using word-processors. MediaWiki is a popular Wiki software which can be extended to allow users to import, edit and export contents using XML DTBook, the format designed by the DAISY Consortium for structuring text in an accessible way.