Analysis of output voltage ripple for dual randomized PWM buck converter operating in continuous and discontinuous conduction modes
Keywords:electro-magnetic interference (EMI), dual randomization, output voltage ripple, buck converter
Dual Randomized Pulse Width Modulation (DRPWM) is renowned for its better effectiveness than Simple Randomized Pulse Width Modulation (SRPWM) in reducing conducted Electro-Magnetic Interferences (EMI) in power converters. However, the introduction of low-frequency ripples into the output voltage by dual randomization has not yet been addressed; this effect is investigated in this paper for a buck converter operating in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM). First, the modulating principle is presented. Then, a general analytical expression for power spectral density (PSD) of the input current is derived and validated for the proposed DRPWM scheme for both the CCM and DCM. A comparison of the PSDs of the input current for all RPWM schemes in both the CCM and DCM shows the PSD spreading effectiveness of the dual scheme as compared to simple schemes. Finally, the low-frequency output ripple is analysed using the PSD of output voltage. The results reveal that the output voltage ripple is affected by all the randomized schemes in both the CCM and the DCM. Also, the dual scheme (RCFM-RPPM) introduces the highest low-frequency voltage ripple, especially in the CCM and for low duty cycles. In DCM, the RPPM scheme gives the lowest voltage ripple, while the RCFM scheme gives the lowest voltage ripple in the CCM. The results are confirmed by both theory and simulations.
M. Miloudi, A. Bendaoud, H. Miloudi. Common and differential modes of conducted electromagnetic interference in switching power converters. Revue Roumaine des Sciences Techniques – Serie Électrotechnique et Énergetique 62(3):246–251, 2017.
P. Lezynski. Random modulation in inverters with respect to electromagnetic compatibility and power quality. IEEE Journal of Emerging and Selected Topics in Power Electronics 6(2):782–790, 2018. https://doi.org/10.1109/JESTPE.2017.2787599.
K. K. Tse, H. Shu-Hung Chung, S. Y. R. Hui, H. C. So. Spectral characteristics of randomly switched PWM DC/DC converters operating in discontinuous conduction mode. IEEE Transactions on Industrial Electronics 47(4):759–769, 2000. https://doi.org/10.1109/41.857956.
Y. Shrivastava, S. Y. Hui, S. Sathiakumar, et al. Harmonic analysis of nondeterministic switching methods for DC-DC power converters. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications 47(6):868–884, 2000. https://doi.org/10.1109/81.852940.
V. Adrian, J. S. Chang, B.-H. Gwee. A randomized wrapped-around pulse position modulation scheme for DC–DC converters. IEEE Transactions on Circuits and Systems I: Regular Papers 57(9):2320–2333, 2010. https://doi.org/10.1109/TCSI.2010.2043997.
H. Guo, Z. Li, B. Zhang. Characteristic analysis of switching voltage power spectra under the mode of random carrier-frequency modulation. COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 29(2):484–494, 2010. https://doi.org/10.1108/03321641011014940.
E. N. Y. Ho, P. K. T. Mok. Design of PWM ramp signal in voltage-mode CCM random switching frequency buck converter for conductive EMI reduction. IEEE Transactions on Circuits and Systems I: Regular Papers 60(2):505–515, 2013. https://doi.org/10.1109/TCSI.2012.2215796.
A. Boudouda, N. Boudjerda, A. Bouzida, A. Aibeche. Dual randomized pulse width modulation technique for buck converter fed by photovoltaic source. Revue Roumaine des Sciences Techniques – Serie Électrotechnique et Énergetique 63(3):289–294, 2018.
K. El Khamlichi Drissi, P. C. K. Luk, B. Wang, J. Fontaine. A novel dual-randomization PWM scheme for power converters. In IEEE 34th Annual Conference on Power Electronics Specialist, 2003. PESC ’03. 2003. https://doi.org/10.1109/PESC.2003.1218102.
A. Boudouda, N. Boudjerda, K. El Khamlichi Drissi, K. Kerroum. Spread spectrum in full bridge DC-DC/DC-AC converter by optimized dual RPWM scheme. The Mediterranean journal of electronics and communications 10(1):666–673, 2014.
N. Boudjerda, A. Boudouda, M. Melit, et al. Spread spectrum in three-phase inverter by an optimised dual randomised PWM technique. International Journal of Electronics 101(3):308–324, 2014. https://doi.org/10.1080/00207217.2013.780299.
Y. Shrivastava, S. Y. R. Hui, S. Sathiakumar, et al. Effects of continuous noise in randomised switching DC-DC converters. Electronics Letters 33(11):919–921, 1997. https://doi.org/10.1049/EL:19970655.
K. Cui, V. Adrian, Y. Sun, et al. A low-harmonics low-noise randomized modulation scheme for multi-phase DC-DC converters. In 2017 15th IEEE International New Circuits and Systems Conference (NEWCAS). 2017. https://doi.org/10.1109/NEWCAS.2017.8010131.
K. Cui, V. Adrian, B.-H. Gwee, J. S. Chang. A noise-shaped randomized modulation for switched-mode DC-DC converters. IEEE Transactions on Circuits and Systems I: Regular Papers 65(1):394–405, 2018. https://doi.org/10.1109/TCSI.2017.2719700.
V. Nguyen, H. Huynh, S. Kim, H. Song. Active EMI reduction using chaotic modulation in a buck converter with relaxed output LC filter. Electronics (Basel) 7(10):254, 2018. https://doi.org/10.3390/electronics7100254.
E. Babaei, H. M. Mahery. Mathematical modeling and analysis of transient and steady states of buck dc-dc converter in DCM. COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 32(1):337–363, 2013. https://doi.org/10.1108/03321641311293920.
D. Stepins. Analysis of output voltage of switching frequency modulated DC-DC converter operating in discontinuous conduction mode. In 2010 IEEE International Symposium on Industrial Electronics. 2010. https://doi.org/10.1109/ISIE.2010.5637199.
D. Stepins, J. Jankovskis. Reduction of output voltage ripples in frequency modulated power converter. Elektronika ir elektrotechnika 119(3), 2012. https://doi.org/10.5755/j01.eee.119.3.1361.
A. Boudouda, A. Bouzida, F. Nafa. Spectral analysis of switch voltage for dual randomized PWM DC-DC converters operating in DCM. International Journal of Electronics Letters 10(1):101–114, 2022. https://doi.org/10.1080/21681724.2020.1870717.
P. Welch. The use of fast Fourier transform for the estimation of power spectra: A method based on time averaging over short, modified periodograms. EEE Transactions on Audio and Electroacoustics 15(2):70–73, 1967. https://doi.org/10.1109/TAU.1967.1161901.
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