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HAIT Journal of Science and Engineering B Volume 2, Issues 5-6, pp. 594-608 © 2005 Holon Academic Institute of Technology | ||||
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Randomized PWM for conductive EMI reduction in DC-DC choppers
Franc Mihalič* and Dejan Kos
Faculty of Electrical Engineering and Computer Science, | University of Maribor, Smetanova 17, 2000 Maribor, Slovenia *Corresponding author: fero@uni-mb.si Received 1 March 2005, accepted 10 June 2005
| In this paper, a comparative investigation of different random modulation schemes against the normal pulsewidth modulation (PWM) for the DC motor drive with step-down chopper (buck) and half-bridge configuration is presented. For this purpose, an experimental setup with DSP2 board has been developed. The board consists of the signal processor TMS320C32 which is suitable for verifying the different modulations strategies. The effectiveness of randomization on spreading the dominating frequencies that normally exist in constant-frequency PWM schemes is evaluated by the power spectral density (PSD) estimations in the low-frequency range. Finally, one universal demo board with two power converters configuration (driven by the micro controller PICF16F876) has been used in EMI measurements to comply with the CISPR 25 (or EN 55025) regulations.
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