Journal ArticleDOI
The Effect of Carrier Frequency Modulation of PWM Waveforms on Conducted EMC Problems in Switched Mode Power Supplies
David A. Stone,Barry Chambers +1 more
TLDR
In this article, a technique of frequency-hopping spread-spectrum modulation was proposed to reduce the spectral power density at harmonics of the switching frequency in switched-mode power converters (SMPCs).Abstract:
SummaryElectromagnetic compatibility (EMC) remains an issue which can present many problems to designers of high frequency power converter circuits. Usual techniques for alleviating the problems of interference generation by power converters involve the use of screening materials and filters, however, the effectiveness of such measures depends on the frequency the interference and the power density at each frequency of interest. As pulse width modulation (PWM) generates high frequency harmonics at multiples of the switching frequency, modulation of the switching frequency may be used to spread the spectral power density present at these harmonic frequencies. This paper presents a technique of frequency-hopping spread-spectrum modulation which may be applied to switched-mode power converters (SMPC’s) to reduce the spectral power density at harmonics of the switching frequency. The influence of the peak frequency deviation, the modulation sequence length and the type of modulating sequence on the resultant ...read more
Citations
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Journal ArticleDOI
Analysis and spectral characteristics of a spread-spectrum technique for conducted EMI suppression
TL;DR: In this article, a detailed analysis and the spectral characteristics of a random carrier-frequency (RCF) technique for suppressing conducted EMI in an offline switched-mode power supply are presented.
Journal ArticleDOI
A comparative study of carrier-frequency modulation techniques for conducted EMI suppression in PWM converters
TL;DR: It is shown that randomCFM (RCFM) gives a more effective way to disperse the harmonics around the switching frequency than the periodic CFM (PCFM) with the same frequency deviation, however, RCFM introduces higher low-frequency harmonics than the PCFM at the converter output.
Journal ArticleDOI
A comparative investigation on the use of random modulation schemes for DC/DC converters
TL;DR: A comparative investigation on the use of random modulation schemes for DC/DC power converters is presented, addressing the effectiveness of randomness level on spreading the dominating frequencies that normally exist in constant-frequency PWM schemes, and the low-frequency power spectral density (PSD) of each scheme.
Journal ArticleDOI
FPGA Implementation of a Switching Frequency Modulation Circuit for EMI Reduction in Resonant Inverters for Induction Heating Appliances
TL;DR: The use of frequency modulation as a spread spectrum technique to reduce conducted electromagnetic interference (EMI) in the A frequency band caused by resonant inverters used in induction heating home appliances is presented.
Journal ArticleDOI
A methodology for true comparison of analytical and measured frequency domain spectra in random PWM converters
TL;DR: The analysis of random pulsewidth modulation (PWM) techniques has matured into a state where analytical expressions have been derived to aid in understanding the frequency domain characteristics as mentioned in this paper, but these expressions require a lot of algebra, and the expressions must be verified by laboratory measurements.
References
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Proceedings ArticleDOI
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Proceedings ArticleDOI
A digitally controlled AC to DC power conditioner that draws sinusoidal input current
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TL;DR: In this paper, an ac to dc power conditioner, which draws sinusoidal input current, is described and analyzed, and two control loops are used: an inner quantized-gain current program loop uses variable hysteresis to improve noise immunity, and a digital proportional-integral control provides output voltage regulation by adjusting the gain of the program loop.
Proceedings ArticleDOI
Random-switching control in DC-to-DC converters
TL;DR: The authors discuss the properties of switching noise in power converters from the viewpoint of the frequency domain and reports experimental switching-noise spectra for two kinds of control, namely, random-switching control and conventional PWM (pulse-width-modulated) control.
Journal ArticleDOI
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Random carrier frequency modulation of PWM waveforms to ease EMC problems in switched mode power supplies
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