A normalized digital compensator for variable frequency PWM

Implementing variable frequency modulation using low-cost digital signal processors introduces two main design issues: variability in the converter response due to the modulator delay, and a widely varying controller response due to the changing sampling period. While the first issue has been modele...

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Bibliographic Details
Published in2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC) pp. 2749 - 2754
Main Authors York, Ben, Hutchens, Chris, Wensong Yu, Jih-Sheng Lai
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.03.2013
Subjects
Digital control
Frequency control
Frequency modulation
Frequency response
Prototypes
Switching frequency
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Summary:Implementing variable frequency modulation using low-cost digital signal processors introduces two main design issues: variability in the converter response due to the modulator delay, and a widely varying controller response due to the changing sampling period. While the first issue has been modeled several times in literature, the second has been largely ignored, and becomes an even greater issue as the frequency range is increased. As a solution, a digital compensator with adaptive gains that is normalized against frequency variations is proposed. A method for calculating the coefficients is also provided, along with a theoretical analysis of the converter frequency response. The frequency-normalized compensator is then implemented on a 180W prototype dc-dc converter, and the improvements in converter stability and system bandwidth are verified experimentally using a frequency response analyzer. For a frequency range of 25-75kHz, bandwidth improvements of up to 300% are shown for the prototype system.
ISBN:1467343544
9781467343541
ISSN:1048-2334
2470-6647
DOI:10.1109/APEC.2013.6520685