A Simple Bilateral Variable-Ratio dc Pulse Converter

A very simple and economical circuit is presented which functions as a bilateral variable-ratio direct voltage transformer.The circuit, which consists essentially of two thyristors, two diodes, and an inductance, is a modification of the familiar pulse converter. When used for the controlof dc machines, dynamic braking is accomplished automatically by feedback of power to the supply. Furthermore, the armature circuit of the machine may provide sufficient inductance for satisfactory operation. Factors which influence the efficiency and the selection of circuit parameters such as operating frequency, component ratings, and the magnitude of the circuit inductance are investigated. The problem of obtaining safe and economical commutation of the thyristors is to be dealt with in a subsequent paper. Test results from an experimental circuit are presented.