Commutation in a Bilateral Variable-Ratio do Pulse Converter

This paper is the second of two dealing with the design and operation of a simple circuit consisting essentially of two thyristors, two diodes, and an inductance which functions as a variable-ratio dc transformer. The circuit provides an economical means of speed control for dc motors by replacing the prime mover and generator of a traditional Ward-Leonard set. This paper considers the behavior of the circuit during commutation under a range of circuit operating conditions and establishes the necessary criteria for the selection of the values of the commutating components which will give reliable and economical commutation.