A methodology for true comparison of analytical and measured frequency domain spectra in random PWM converters

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. Derivations of the formulae require a lot of algebra, and the expressions must be verified by laboratory measurements. It is shown, however, that factors originating from digital signal processing techniques make the comparison difficult if proper measures against misinterpretation are not taken. A methodology to overcome the problems is presented. Novel expressions for the random lead-lag pulse position technique and the random switching frequency technique are also presented as well as their verifications by laboratory measurements on a full-bridge DC/DC power converter.

[1]  Frede Blaabjerg,et al.  Improved modulation techniques for PWM-VSI drives , 1997, IEEE Trans. Ind. Electron..

[2]  William H. Press,et al.  Numerical recipes in C. The art of scientific computing , 1987 .

[3]  Frede Blaabjerg,et al.  Analysis of Spectral Effects of Random PWM Strategies for Voltage-source Inverters , 1997 .

[4]  Robert B. Randall.  Frequency Analysis , 1987 .

[5]  Frede Blaabjerg,et al.  Random pulse width modulation techniques for converter fed drive systems-a review , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[6]  A.M.N. Lima,et al.  Current control for a random PWM voltage source inverter , 1997, PESC97. Record 28th Annual IEEE Power Electronics Specialists Conference. Formerly Power Conditioning Specialists Conference 1970-71. Power Processing and Electronic Specialists Conference 1972.

[7]  George C. Verghese,et al.  Analysis and synthesis of randomized modulation schemes for power converters , 1993 .

[8]  P. Welch.  The use of fast Fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms , 1967 .

[9]  David A. Stone,et al.  The Effect of Carrier Frequency Modulation of PWM Waveforms on Conducted EMC Problems in Switched Mode Power Supplies , 1996 .

[10]  Jonathan H. B. Deane,et al.  Some applications of chaos in power converters , 1997 .

[11]  William H. Press,et al.  Book-Review - Numerical Recipes in Pascal - the Art of Scientific Computing , 1989 .

[12]  Mihajla Stankovic Aleksandar.  Random pulse modulation with applications to power electronic converters , 1993 .

[13]  Frede Blaabjerg,et al.  Random Modulation Techniques in Power Conversion: an Update , 1996 .

[14]  D. Middleton.  An Introduction to Statistical Communication Theory , 1960 .

[15]  R. L. Kirlin,et al.  Power spectra of a PWM inverter with randomized pulse position , 1993 .

[16]  Frede Blaabjerg,et al.  Optimized and Non-Optimized Random Modulation Techniques for VSI Drives , 1996 .