Harmonic analysis method for converter

A method to analyze the harmonics generation mechanism of converters is presented,which takes into account the interaction between the harmonics generated by converter and the power system. Based on the modulation theory and the Fourier analysis theory,the relations among the AC-side and DC-side variables of converter are explored in frequency-domain. It is found that a harmonic coupled admittance matrix can be used to represent the relations between the AC-side harmonic voltage and current of converter,which is a constant matrix. Its elements are independent of the harmonic voltages at supply side of conver-ter. The model transforms the nonlinear characteristics of converter in time-domain into a linear admittance matrix in frequency-domain,directly and accurately reflecting the coupling degrees among the AC-side harmonic voltages and currents of converter. It has higher accuracy and no iteration is necessary. The time-domain case study verifies its validity and accuracy.