The Output Spectrum Analysis of High-Power Multilevel Voltage Source Converters using Double Fourier Series

This paper presents a theoretically analytical technique for determining the spectral components of high-power multilevel voltage source converters. The technique uses double Fourier series to analyze the output waveform of multilevel asynchronous asymmetrical regular sampling SVPWM converter. The 3-D spectrum representation of the SVPWM based on the extension geometrical-wall-model is given in this article. According to the analytical method of two-level SVPWM and the phase-shifted carrier PWM, the new DFS of multilevel SVPWM of single phase is obtained. In order to validate the theoretically analytical method, a six modules cascaded H-bridge converter model using PSCAD is built. By comparing the spectrum and waveform calculated with the simulation, the correctness of the analytical formulas has been proved. And the technique can act as the method of selection PWM. Moreover, the technique can be used to analyze the output waveform of the high-voltage and high-power FACTS equipments, such as SVG, SSSC, UPQC