Abstract
M.Ing.
Power supplies for pulsed laser applications are required to produce high energy pulses of microsecond and sub microsecond duration. Gas phase switches have traditionally been used in these applications. The exorbitant replacement as well as running costs, coupled with the limited lifetime of these switches, has led to the investigation of the implementation of an equivalent semiconductor switch. The semiconductor switch consists of thyristors coupled in series. This switch is connected to a two stage ferrite pulse compressor in order to achieve the required output pulse shape. The use of series coupled thyristors as high voltage switches in fast switching applications has been limited to laser and radar applications. Little has been published about work in this field and it was necessary to investigate the characteristics of the switching elements, under pulsed conditions, in order to optimise the switching and conduction losses of the elements as well as the switch as a whole. This investigation led to the development of an 18 kV switch which produces 750 nanosecond pulses at a repetition rate of 10 kHz. The applicability of similar switches in the radar and laser fields is discussed.