High Power IGBT Modules for Marine Drive Applications (HiDrive)

This project builds upon the successful UK based development by De Montfort University, Semelab and Dynex of an innovative device technology called the Clustered IGBT (CIGBT). Through various collaborative research projects, CIGBT devices have been developed at 1200V and 1700V ratings, funded through EPSRC and industrial support. These devices combine a thyristor current carrying capability with MOS gate control and a unique self-clamping feature to provide low on-state and switching losses whilst still maintaining a wide safe operating area. Electrical results from pre-production 1200V devices show significant reductions in on-state forward volt drop whilst still maintaining similar switching losses to that of an IGBT technology. This project will analyse, for the first time, the device structure at higher operational voltages at and above 3.3kV. This device technology is well suited for high voltage operation as the thyristor current carrying mechanism will provide low on-state losses, which are the dominant losses for such high voltage applications. Preliminary simulations of a 3.3kV CIGBT structure indicate that for similar switching losses to an IGBT the current density through the die can be increased by 20%, therefore making the technology well suited for marine drive and other applications that can benefit from increased power density. Novel busbar connection strategies will free-up module footprint area for extra silicon, thus further increasing power density. Studies will include: a) the use of internal busbars to control electric field strength within backfill material and at metallised edges of the substrates, thereby reducing susceptibility of insulation system to partial discharge and eventual failure and b) the decoupling of internal busbar cooling from the substrate by transferring this function to the converter interconnecting busbars, thereby reducing the baseplate temperature rise. Both of these innovative approaches will significantly increase power density by making use of the Z-axis dimension and taking functionality from the baseplate.