Fully controlled regenerative bridges with half-controlled characteristics

The paper describes a means of control for fully controlled thyristor bridges which effects regeneration of energy to the a.c. supply source and still maintains the better power-factor and ripple characteristics usually associated with half-controlled rectifier arrangements. The technique is applicable to polyphase bridge circuits but the advantages are greatest in the handling of large single-phase powers such as occur in a.c.-fed traction systems. Although these advantages are applicable to d.c. motor control schemes the convertor bridge characteristics are naturally suited for use with current-source-type invertor-controlled a.c. motors. Such control techniques may thus prove vital in the consideration of a.c.-motor schemes for a.c.-supplied traction applications.