DC link harmonics of three phase voltage source converters influenced by the pulse width modulation strategy-an analysis

DC link current harmonics are the predominant factor to be considered for dimensioning DC capacitors in three phase PWM voltage source converters. In this article an analysis of the DC link current harmonics applying double Fourier series is derived. The analytical results for the DC link current spectra of continuous and discontinuous PWM are presented and compared with measurement results taken from a converter test setup. A good match between theoretically expected and actually obtained experimental results can be stated. Moreover significant differences between the investigated modulation strategies regarding their DC link current spectra can be found.