Liquid cooled Variable Speed Constant Frequency (VSCF) converter device development

Further miniaturization of high-power semi-conductor devices utilizing silicon disks larger than 12 mm. requires major innovations to improve the average thermal impedance and surge capability. The high thermal impedance in existing discrete devices is caused mostly by the dry interfaces necessary to provide stress relief. This report presents a unique approach to solving the dry interface problem. It describes the design, fabrication and evaluation of a smaller, lighter, electrically isolated dual thyristor module featuring structured copper, solder bonding, polyimide passivation, direct bonded copper on beryllium oxide and a hermetic sealed aluminum case. Details of the SCR modules evaluation in a 60 KVA single channel VSCF electrical generating system are included.