Abstract
This paper investigates the validity of the
sampling theorem in the analysis of supply side line current
harmonics as applied to 6-pulse AC-DC thyristor converters.
The common pattern of the percentage harmonic factor, for the
converter characteristic harmonic current, per incremental
change of the thyristor firing angle is used as the basis of the
study. The RMS values of the peak amplitudes of the
characteristic harmonic currents induced in the input-phase of
the converter supplying a DC motor are described in terms of
the sampling theorem equations and further evaluated in terms
of their respective individual harmonic contributions as the
thyristor firing angle is changed. The MatLab/Simulink package
is also employed to simulate the forward drive speed control
operation of a DC motor using the 6-pulse AC-DC thyristor
converter. However the percentage harmonic factor trends
observed in the sampling theorem method appear to be
generally increasing which is in contradiction to the
MatLab/Simulink produced trends.