Press pack boost for high voltage IEGTs

Technology News |
By Nick Flaherty

The new packaging has been developed to improve the rupture resistance of the device for the press pack IEGT (PPI) format to avoid damage to surrounding components and systems in high current designs.

An IEGT is a voltage-driven device for switching large current. Insulated-gate bipolar transistors (IGBTs) with high collector-emitter voltage (VCES) have difficulties with the sharp increase in on-state voltage in the high current region. To overcome this, IEGTs use a unique emitter structure with a higher turn-off performance and the wider safe operating area.

Toshiba has already launched a high–current 4500V, 1200A power module as a plastic case module IEGT (PMI) measuring 140mm x 190mm but the PPi package is the result of research undertaken to evaluate the optimum volume ratio of materials. Through experimentation the optimal ratio was determined where neither destruction of the ceramic, nor material leakage occurred.

 After careful measurement, the package was shown capable of withstanding 50 hours of short-circuit failure mode (SCFM). The experiment was executed with one shorted IEGT chip, out of 42 IEGT chips, in a worse-case edge location. The rupture resistance tests, undertaken at a 3200 V test condition, resulted in 1.7 times higher resistance than that of standard PPI devices.

IEGTs are aimed at applications such as High-Voltage Direct-Current (HVDC) Transmission converters, Static VAR Compensators (SVCs), rail traction and light rail power systems. The

The MG1200GXH1US61 PMI (plastic case module IEGT) integrates an N-channel IEGT (injection-enhanced gate transistor) and a fast recovery diode (FRD) with an isolation voltage rating of 6000 VAC rms for one minute and can handle a peak turn-off collector current of 2400A. Collector power dissipation (at 25°C) is 4000W. An operating temperature range of -40°C to +150°C ensures compatibility with the extended temperature environments of high voltage applications.

Toshiba will be discussing the technology at the PCIM exhibition next week.


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