Series connection of IGBTs Effective factors for voltage sharing: device characteristics driver static dynamic ∆ICES, ∆Tj ∆Tj, ∆Vgeth, ∆tdon, ∆tdoff, ∆Qrr - ∆Lwire , ∆ton, ∆toff Recommendations: use devices of one production lot (smallest parameter deviations guaranteed) symmetrical design of gate driver (minimize deviations of delays) symmetrical cooling conditions (identical heat-sink temperature and flow rate below the series connected devices) use parallel resistors with IR ≈ 5..10 x I CESmax to enforce static voltage sharing use RC snubber to equalize voltage rate of rise Dr. Schütze SM PD Series connection of IGBTs Snubber circuit: parallel resistor for static voltage sharing CG-clamping RC snubber for dynamic voltage sharing Dr. Schütze SM PD Alternative: use of 3- or multi-level circuit configurations