Chopper circuit for feeding multiple independent loads - uses gate controlled turn-off thyristor to operate without need for special commutating circuits

摘要

The circuit is primarily intented for the supply to multiple motor drives (6a, 6b). A chopper or interruptor (2) of solid state type controls the connection of a battery (1) to the variable terminal (SP) of an alternating output. The chopper is typically a transistor or gate controlled turn-off thyristor. For each load (6a, 6b) a separate series pair of oppositely poled devices, one controlled (4a, 4b) and one uncontrolled (5a, 5b), is provided, with one terminal of the load connected to the common point (Qa, Qb). The instant of switch on of power to the load is determined by the instant at which the controlled device (4a, 4b) is triggered with respect to the intermittent potential on the busbar (SP). Switch off is determined by the turn off of the chopper. An auxiliary turn off circuit (3) giving reverse bias to the bus (SP) may be added if necessary to ensure that all devices turn off.