Freewheeling diodes reduce losses in IGBT designs
The Infineon Prime Soft diode features an improved turn-off capability rated at 5 kA/µs and builds on the existing Integrated gate-commutated thyristor (IGCT) freewheeling diode family which uses a monolithic silicon design. Typical applications for the diodes are HVDC voltage source converters and medium voltage drives.
The lower losses come from the monolithic silicon design creating an active silicon area increased by more than 25 percent compared to multichip diodes. This improves the switching power up to 6 to 10 MW at a maximum junction temperature of 140°C. Compared to a free-floating contact without solid metallurgical connection between silicon and molybdenum carrier, the thermal resistance of the new, bonded device is about 20 percent lower.
In addition to the high standards on reliability and good thermal properties, Infineon Prime Soft diodes feature minimum switching losses. Its soft reverse-recovery behavior shows no improper oscillations under all relevant operating conditions. The new mechanical design simplifies the stack construction with series stacking of press-pack IGBTs and the freewheeling diodes. This reduces the time needed for stack design by about 50 percent.
The ultra-soft freewheeling diodes in press-pack housings are available with 4.5 kV blocking voltage. The diodes come in three different silicon diameters: D1600U45X122, D2700U45X122, and D4600U45X172.