DESIGN AND DEVELOPMENT OF A ±2kV ±10kA HIGH SPEED GTO SWITCHING AMPLIFIER FOR FAST EQUILIBRIUM CONTROL ON COMPASS-D

One aim of the COMPASS-D Tokamak facility is the study and control of plasma equilibrium including plasma disruption events which can occur over very short timescales. A high power (±2kV ±10kA) high speed (<100μs voltage response time) four quadrant amplifer system is required and this will use Gate Turn-off Thyristors (GTOs) in a bridge switching circuit powered by a capacitor bank. The high speed and high current performance requirements are at the limit of present GTO technology and so a development programme was undertaken. The paper describes the development programme and the proposed design of the power amplifier system.