Frequency-Domain Modeling of Multipulse Converters by Double-Fourier Series Method

Operation of multipulse converters can be conveniently described in the frequency domain by using their voltage and current mapping functions. Applications of such mapping functions include input impedance modeling of multipulse rectifiers, analysis of harmonic transfer and impedance coupling through high-voltage dc transmission lines, and input harmonic current distortion of multipulse rectifiers under unbalanced and/or distorted source conditions. The existing approach to spectral modeling of the mapping functions requires small-signal assumption and commensurability between the ac source fundamental frequency and the harmonic frequency. A new spectral modeling method based on double-Fourier series analysis is presented. The proposed method overcomes the limitations of conventional Fourier analysis and provides a more rigorous basis for frequency-domain analysis of multipulse converters.