Optimum Design of Commutation Circuit in a Thyristor Chopper for DC Motor Control

This paper deduces the expressions for the commutating capacitor voltage and current during the commutation period of the main and auxiliary thyristor in a chopper for a dc motor control system. After a successful commutation, a certain amount of energy is ``stored'' in the circuit components, and for best component utilization this stored energy has to be minimized. The procedure of minimum stored energy in the commutation circuit has resulted in the selection of optimum values of commutating capacitors and inductors, and the values so obtained are more precisely defined than those indicated by early workers.