Planar Transformers Excited by Square Waves

Abstract

Abstract-This paper presents an analysis of found results in experiments developed with transformers built with planar coils, when they are excited by square waves, in comparison with transformers built with planar coils inner ring coils. The transformer was built joining two planar coils one over the other. In this kind of transformer, similar responses as analysis of transformers built with planar coil inner ring coil are found, as well the results of resonance. Because the low self-inductances and parasitic capacitances obtained in these configurations, although the coils resistance is low, which generates low exponential drops on responses. The resonance is found in higher frequencies, but satisfying conditions of sum of responses in resonance.

Coupling Impedance Between Planar Coils Inside a Layered Media

“…Several studies on two planar coils with parallel axes have been carried out by various authors [2][3][4][5][6][7]. These are particularly useful in applications concerning contactless energy transfer [8][9][10][11][12][13].…”

Effects of Induced Electromotive Force (EMF) in Transformers Built with Planar Coils

“…Nesta perspectiva, trabalhos utilizando bobinas planas são basicamente em microcircuitos [6]- [10] e, em alguns casos, estudos de parâmetros como indutância ou indutância mútua dessas bobinas [11]- [17]. Nessa área, pouco se encontra de estudos a respeito de respostas de indução eletromagnética em transformadores construídos com bobinas planas excitados por ondas quadradas, em que se vêem trabalhos como [18]- [21] para o caso de bobinas planas internas a bobinas em anel. As respostas transitórias vistas nestes trabalhos se mostram como importantes formulações para análises de capacitâncias parasitas [22]- [25], bem como estudos de ressonância [20], [21], [25], [26] e aplicações em transformadores de pulso [27]- [33].…”

Resonance Analysis of Induced EMF on Coils

“…where  is a constant referring to peak response of the sine wave, a is a constant referring to DC level in response, b is a constant referring to exponential attenuation and p is the time www.intechopen.com when occur each change in the square wave, as we can see in (Costa, 2009c;Costa, 2010a) for some aspects of resonance on coils. Due to the sum of responses, we find that when the responses is in phase with the square wave, i.e., the relation f r = f s /n, we find a maximum value in output, which refers to the sum of the sine waves in phase and their DC components.…”