DIII-D F-coil chopper selection, control and fault recognition system

The DIII-D fusion experiment uses 18 field-shaping coils (F-coils) to control the position and shape of a plasma discharge. The DIII-D F-coils are powered and controlled by configuring single or parallel operation of up to 50 modular, 3-kA, 3-kHz, 2-quadrant-switching power supplies (choppers) and nine DC power supplies. The DC power supplies provide the raw power for the choppers while the choppers control the current in the F-coils. The chopper selection, control, and fault-recognition system uses state-of-the-art computer bus switching networks and programmable array logic (PAL) circuitry. The chopper selection and control system uses the computer bus switching networks to select individual chopper controls for a specific F-coil. A fault system capable of managing over 100 faults was developed using flexible PAL circuitry programmed for the application. The fault system identifies the first fault to occur and takes appropriate action for controlled safe termination of a shot. Additional faults are flagged and new responses taken if required