Spectral Null Generation using Pulse Width Modulation in DC-DC converters

Abstract

Electrical infrastructure of modern society is highly dependent on the power electronic systems for conditioning of electrical power from the raw power of the national grids. All modulation schemes create trains of switched pulses, which also contain unwanted harmonic components that need to be minimized. Resulting electromagnetic interference may disturb operations of sensitive instruments, necessitating the use of filters. Random pulse width modulation (RPWM) creates continuity in the output voltage of power spectrum thereby, reducing the discreteness. The current study focuses on the experimental and theoretical aspects of RPWM method by creating a new technology which leaves the power control method unaffected, transfer the harmonic power in frequency spectra of voltage and current to power spectral density while creating dips in noise spectra. The objective of this method is to improve conditions for long and medium wave conditions.The method presented in this thesis effectively suppresses specified components in the spectra of voltage noise of dc-dc power electronic converters. Computer simulations and laboratory experiments confirm the validity of the proposed theory of spectral nulls in the dc-input power electronic converters.