Experiment Research of Chaotic PWM Suppressing EMI in Converter

Abstract

Based on the analysis of constant frequency, periodical frequency-spreading scheme and chaotic frequency-spreading scheme, the article has discussed the mechanics and the characters of the chaotic PWM suppressing EMI in the converter. Experiments have been made on an AC-DC forward converter. The experiment results show that the EMI spectrum is decided completely by the PWM spectrum, and the chaotic frequency-spreading has an obvious impact on EMI suppressing, compared with the other schemes. The frequency character of the ripple has been changed but the peak value and the shape of the ripple have kept almost the same as before, and after the frequency is spread chaotically, the converter system works stable. The article has made up the lack of theory analysis and experiment analysis of chaotic PWM suppressing EMI.

A Chaotic Peak Current-Mode Boost Converter for EMI Reduction and Ripple Suppression

“…The broadband spectrum discussed in the previous section suggests the chaotic nature of the boost converter expressed in (9). In the sequel, this nature is further investigated with the use of bifurcation diagrams and Lyapunov exponents.…”

“…The chaotic nature is confirmed by the existence of positive LEs, while some periodic windows are observed in between. According to (9), periodic windows exist when , and (9) can be written as corresponding to . Similar bifurcation diagrams of versus and versus can be obtained.…”

“…Moreover, the power of the background spectra has been increased in most designs, although the peak values of the power spectrum are reduced, resulting in larger power consumption. These two disadvantages not only exist in the peak current-mode controlled boost converters, but also in other chaotic power converters [8], [9], which have seriously impeded their popularity. Hence, answering the questions of how to improve the control method for chaos-based dc-dc converters so that low EMI and small output ripples can be achieved and how to verify the relationship between the ripples and background spectrum constitutes the concern of this paper.…”

EMI mitigation in switching power converters combining closed‐loop gate drive and chaotic frequency modulation technique

“…Among these frequency modulation techniques, the chaotic frequency modulation technique is an emerging technology for EMI mitigation which enables the converters to generate switching waveforms with continuous spectra. The researches on switching power converters under chaotic frequency modulation have been settled on theory analysis [19,22,23], simulations, and experiments [24][25][26]. It has been presented that the chaotic frequency modulation technique can mitigate interference effectively.…”

Chaos versus EMI: Methodologies and Practice

“…As the frequency and amplitude of a carrier or a modulation signal are invariant, there are biggish peaks close to its fundamental frequency and its multiples over the spectrum. This makes it difficult for converters to meet the international EMC standards, which are the market access standards for electrical and electronic products [Yang et al, 2006]. Firstly in 1995, Hamill applied chaos to modulate the frequency of the carrier [Hamill, 1995], and then Marrero, Font and Verghese explained that the harmonics of the converters are distributed continuously under chaos control [Marrero et al, 1996].…”