IEGTs cut losses in high-power applications

New injection enhancement gate transistor modules combine high power densities with reduced losses to improve the performance and efficiency of applications switching voltages up to 4.5kV.

The latest injection enhancement gate transistor (IEGT) technologies from Toshiba combine high power densities with reduced losses and can significantly improve the performance and efficiency of applications requiring the switching of voltages up to 4.5kV Toshiba's new 4.5kV press pack IEGT (PPI) and 3.3kV IEGT module are ideally suited to high-end motor drives, uninterruptible power supplies (UPS), power transmission schemes, HVDC designs, transportation systems, and other very high-power applications.

The 4.5kV PPI is made up of multiple IEGT chips and will work with currents as high as 2.1kA, whereas the 3.3kV module comprises 24 IEGT chips and 12 diode chips and handles currents up to 1.2kA.

IEGTs employed in the new 4.5kV/2.1kA PPI have been optimised for low loss operation.

As a result, Toshiba has been able to reduce device saturation voltage by 1.3V when compared to the previous generation of 4.5kV PPI parts.

In the case of the 3.3kV module, Toshiba has used optimised lifetime control techniques to improve the reverse recovery characteristics of the free wheeling diodes (FWDs).

This has reduced maximum dv/dt to 7.5kV/us, or just 50% of the maximum dv/dt of the previous generation of 3.3kV IEGT modules.

In addition, optimisation of carrier distribution in the cathode area has helped to minimise diode oscillation under severe switching conditions.

The new 4.5kV PPI has a package diameter of 125mm and the 3.3kV IEGT module has a footprint of 140 x 190mm.

PPI packaging allows for cooling on both sides for improved thermal management.

In addition, as there are no wire bonds or solder contacts, the PPI also provides high levels of resilience to thermal cycling.

An AlSiC base plate and optimisation of internal components ensures that high reliability operation is also a key feature of the 3.3kV device.

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