An extended analysis of 6-pulse AC/DC converters taking account of commutation

In this paper we carry out an extended analysis of 6-pulse AC/DC converters, when the DC motor supplied by the converter itself is modelled with its internal R-L parameters and e.m.f. E in series equivalent, considering also the real commutation of power devices. The motor current is calculated without usual simplifying hypotheses, then the r.m.s. values of each harmonic component are determined by means of the expansion in Fourier series of the line currents. Finally we calculate some important performance factors such as the fundamental factor, the displacement factor and the power factor, the total and individual harmonic distortion of the line currents, for different load conditions.