Showing papers on "Power electronics published in 1972"
01 Feb 1972
TL;DR: In this paper, a bridge of four solid-state switches with a capacitor in one diagonal is connected in series between the supply and the load, periodically reverse the current flow direction through the capacitor.
Abstract: A bridge of four solid-state switches with a capacitor in one diagonal is connected in series between the supply and the load. The switches (thyristors) periodically reverse the current-flow direction through the capacitor. The load power is controlled by varying the switching frequency. The device may be used for the control of direct current and alternating current.
34 citations
TL;DR: In this paper, the authors proposed to improve the low power factor of phase-controlled converters when the output voltage is less than the maximum by firing or gating the thyristors in two groups asymmetrically.
Abstract: The low power factor of phase-controlled converters when the output voltage is less than the maximum is of-concern in high-power equipment. In a converter consisting of two commutating groups in cascade, the usually low power factor can be improved by firing or gating the thyristors in the two groups asymmetrically. One of the groups is fully advanced (or retarded) to minimize its reactive power, while the other group is controlled to give the desired dc Output. The technique is not recommended for single three-phase bridge converters because of third-hannonic output ripple, second-harmonic line current distortion, and danger of commutation failure. These objections are overcome by combining pairs of three-phase bridges. When regeneration is not required, half of the thyristors can be replaced by diodes, reducing the cost. The method should offer substantial improvement in the power factor of cycloconverter ac motor drives as well as dc motor drives.
23 citations