Tools for HV semiconductor measurement

GEC ALSTHOM Engineering Research Centre (ERC) have been carrying out measurements into high power semiconductor devices for several years on behalf of companies within the GEC ALSTHOM group. The work involves characterisation of new power semiconductor devices prior to their adoption by the product groups within GEC ALSTHOM, and the resolution of problems by device-circuit interaction encountered in their practical application. This work is carried out by ERC´s Applied Physics Group. High power thyristors of up to 5.2 kV, 3 kA, gate turn off thyristors (GTOs) up to 4.5 kV, 4 kA and insulated gate bipolar transistors (IGBTs) up to 1.2 kV, 400 A have been operated at frequencies between 20 Hz and 10 kHz, to the limits of power of the test circuits employed. A considerable experience has been accumulated in the development of gate drives and snubbing circuitry. Failure modes in devices can also be investigated allowing `post mortems´ to be carried out. Thus ERC also carries out analysis on failed devices sent from many clients