1,720,985 research outputs found
Analysis of Switching Frequency Modulated Synchronous Buck Converters
No full textThis paper is devoted to the analysis of the effect of switching frequency modulation (SFM) used for EMI reduction on the synchronous buck converters (SBC) parameters, such us output voltage ripples (OVR), peak power component currents, etc. In the paper SBC are studied analytically, using computer simulations and experimentally. The most careful attention is paid on the peak-to-peak OVR because it is the most problematic parameter due to the use of SFM. Several useful guidelines for the choice of SFM parameters and slight modification of the control circuit to get peak-to-peak OVR as small as possible are also proposed. The results presented in the paper can simplify the design of SBC with SFM
Analysis of Output Voltage of Switching Frequency Modulated DC-DC Converter Operating in Discontinuous Conduction Mode
No full textIn this paper analysis of output voltage ripples of a switching frequency modulated (SFM) buck converter operating in discontinuous conduction mode (DCM) is performed. The ripples are analyzed in both time and frequency domains by the use of theoretical derivations and computer simulations.
Significant increase in output voltage ripples under DCM is
observed after using periodic SFM. Low frequency variations at
modulation frequency are considered as the most problematic.
Cause of the problem is revealed. Influence of main nonidealities
of the converter and modulation parameters on the
output voltage ripples is analyzed. Experimental verification is
also performed to confirm the theoretical evaluations and
simulation results. The analysis can give useful information
when designing a SFM power converter
Examination of Power Converters with Modulated Switching Frequency
No full textIn this paper analysis of output voltage ripples of a switching frequency modulated (SFM) boost converter operating in continuous conduction mode is performed. The ripples are analyzed in both time and frequency domains theoretically and using computer simulations. Increase in output voltage ripples is observed after using periodic SFM. Low frequency output voltage variation is revealed to be the most problematic. Cause of the problem is found out. Influence of main non-idealities of the boost converter and modulation parameters on the output voltage ripples is also analyzed. Experimental verification is also performed to confirm the theoretical evaluation and simulation results. Some recommendations are given to improve usefulness of periodic SFM in boost converters
Examination of Influence of Periodic Switching Frequency Modulation in dc/dc Converters on Power Quality on a Load
No full textŠajā darbā ir izpētīta periodiskas komutācijas frekvences modulācijas metodes (PKFMM) ietekme uz spēka dc/dc pārveidotāju enerģijas kvalitāti uz slodzes. Eksperimenti tiek veikti izmantojot pazeminošu impulsu pārveidotāju kura komutācijas frekvence ir modulēta ar sinusoidālu signālu. Eksperimentālie rezultāti ir arī salīdzināti ar modelēšanu Pspice. Rezultātu analīze parāda, ka pielietojot PKFMM, palielinās izejas sprieguma pulsācijas, kā arī izejas sprieguma spektrā parādās modulācijas frekvences harmonikas. Cēloņi, kāpēc šie blakus efekti parādās ir noskaidroti un efektīvas metodes šo efektu samazināšanai arī ir piedāvātas
Impact of Periodic Frequency Modulation on Power Quality of Switching Power Converter
No full textIn this paper power quality of switching
frequency modulated (SFM) power converters is
analyzed in details. Careful attention is paid on the
effect of SFM parameters on switching power
converter input current total harmonic distortion
(THD) and power factor. Theoretical analysis,
simulations and experiments show that SFM used for
electromagnetic interference reduction in switching
power converters has almost invisible impact on input
current THD and power factor of conventional
switching power converters
Conducted EMI of Switching Frequency Modulated Boost Converter
No full textIn this paper conducted electromagnetic interference (EMI) of boost converter with switching frequency modulation (SFM) is theoretically analyzed in details. In the analysis line impedance stabilization network parameters, power inductor and input filtering capacitor parameters are taken into account. The analysis shows that the conducted EMI attenuation due to the use of SFM depends not only on modulation index as it is assumed in numerous research papers, but also on central switching frequency. Useful expressions to numerically calculate SFM boost converter conducted EMI spectrum and attenuation due to the use of triangular and sawtooth modulation waveforms are derived. Additionally experimental verification of the theoretical results is performed using a superheterodyne spectrum analyzer. Moreover a procedure for the choice of optimum SFM parameters (modulation waveform, frequency deviation and modulation frequency) to get maximum conducted EMI attenuation is proposed
Improving EMI Attenuation in Frequency Modulated Power Converters
No full textThe effect of frequency modulation on a power switching converter electromagnetic interference (EMI) attenuation is examined in this paper. A method known as “modified sawtooth” is applied for EMI attenuation in a boost converter and it is optimized in such a way to reduce EMI more effectively. The method is also verified experimentally by the use of a low power boost converter controlled via an arbitrary waveform generator. EMI attenuation up to 15 dB is achieved after using modified sawtooth modulating waveform
Effect of Frequency Modulation on Input Current of Switch-Mode Power Converter
No full textComprehensive theoretical analysis of the effect of switching frequency modulation (SFM) on input current of DC/DC switch-mode power converters (SMPC) operating in discontinuous conduction mode (DCM) is presented. Theoretical and SIMULINK simulation results are verified experimentally. Peak input and power components currents increase and low-frequency harmonics appear in the input current due to the use of SFM. Some considerations on the right choice of modulation parameters to reduce the negative effects considering also output voltage ripples and electromagnetic interference attenuation are proposed. The analysis performed can be very useful for a design of DC/DC SMPC with SFM in DCM
Impact of Periodic Frequency Modulation on Power Quality of Switching Power Converter
No full textIn this paper power quality of switching frequency modulated (SFM) power converters is analyzed in details. Careful attention is paid on the effect of SFM parameters on switching power converter input current total harmonic distortion (THD) and power factor. Theoretical analysis, simulations and experiments show that SFM used for electromagnetic interference reduction in switching power converters has almost invisible impact on input current THD and power factor of conventional switching power converters
On the Figures of Merit for Planar Spiral Inductors
No full textDaži planāro spiraļspoļu (PS) labuma kritēriji ir piedāvāti un analizēti. Daži no tiem atrasti zinātniskās publikācijās un citus piedāvājam mēs. Lielāka daļa no šiem kritērijiem ir stipri atkarīga no ārēja diametra, tāpēc tie nedod mums iespēju analizēt citu parametru ietekmi uz PS kvalitāti. Ar nolūku novērst šo trūkumu, labuma kritērijs, vāji atkarīgs no ārēja diametra ir izvests. Šis kritērijs dod iespēju, piemēram, pielietot PS parametru mērogošanu
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