Harmonic and loss reduction in three-phase thyristor-controlled AC/DC converters for reactive power compensation

In this paper a new control method for the conventional, 12-pulse, thyristor-controlled, AC/DC converter for reactive power compensation is presented. A relatively small inductance is used with its rated current reached in the discontinuous mode to have a discontinuous rated inductor current. This results in lower inductor size, cost and loss, and greatly reduces the converter switching losses. With a proper choice of the control range and inductor size, a great reduction in the AC harmonics has been achieved. Experimental results are shown to demonstrate the validity of the proposed method