Performance parameters of phase controlled converters at various fixed load DC voltages

In practice, in a three-phase AC-DC phase angle controlled converter the load is assumed to be static and is R-L type. In this type of load the L/R ratio and the converter delay angle (α) determines the range where the converter can operate in continuous current mode. A relatively high R/L ratio keeps the converter at continuous current mode, even at high delay angle. However, this situation changes drastically if the load contains a fixed DC voltage in the form of back EMF (electromotive force) of a DC machine. A three-phase AC-DC converter is analyzed and the performance parameters of the converter under various fixed DC voltages (E_c) are evaluated. It is found that, depending on the E_c and the delay angle, the performance of the converter and the continuity of the load current change significantly