A Linear Thyristor Power Stage with Self-Limiting Firing Circuits

The requirements of a thyristor power amplifier for control purposes are examined, and the techniques for design of firing pulse circuitry to achieve linear input-output voltage transfer relationships are developed. The particular converter discussed has this linearity, inherent compensation for ac supply voltage variations, self-limiting firing circuits, and transition from constant voltage to constant current behavior at preset levels of either. Long pulse firing is used and the pulse duration adjusts itself automatically to meet any transient condition. Protection against over-voltage, over-current, regenerative load effects, and misfiring are included. The applications considered are in the tens of kilowatt rating range.