13IGBT or SiC for the traction module?
Start from bus voltage and efficiency target. A 400V platform is well served by mature 750V IGBT modules. On 800V platforms, or wherever switching frequency is pushed up, 1200V SiC cuts switching loss and shrinks heatsink and passive volume. SiC is not a part-number swap: gate voltage, dv/dt and short-circuit withstand time need a SiC-specific design, and the isolated driver usually needs CMTI of 100 kV/μs or more. Listed automotive modules come in 650V/750V/1200V classes, with 1200V aimed at traction.
14IGBT module or discrete?
First check whether the power tier and topology are standard. Low-power or single-phase designs (roughly below 20 A) suit discrete IGBTs with external drivers and free layout; three-phase designs above about 30 A suit modules — shared baseplate cooling, low parasitic inductance, isolation and creepage already engineered. Then ask two more questions: can the team develop its own drive and protection circuitry, and is maintenance a whole-module swap or a single-device repair? Listed discretes cover about 15A~150A, modules 15A~950A.
15How to trade VCE(sat) against switching loss?
Within one voltage class, a part with lower VCE(sat) usually has a longer turn-off tail and higher Eoff. Drives at 4~16 kHz carrier lean towards low VCE(sat); high-frequency welders and UPS links lean towards low Eon+Eoff. Sum conduction and switching loss at the real carrier frequency, then check junction temperature through Rth(J-C). Align test conditions before comparing: VCE(sat) moves with gate voltage and junction temperature, and switching loss is usually quoted at Tj=125°C, so figures taken under different conditions are not directly comparable.
16Why do PV inverters so often use three-level topologies?
Three-level topologies expose each switch to only half the bus voltage, so 650V devices can serve a 1000V DC bus with lower switching loss and lower output harmonics. The trade-off is twice the device count and drive channels, which is why dedicated three-level modules are used to contain size and layout. Set the voltage class from the maximum DC-bus voltage plus margin — listed PV and ESS modules come in 650V and 1200V classes — then filter the IGBT module category by the 3-Level configuration.
17Why do appliance inverters use IPMs rather than discrete IGBTs?
An IPM packs six IGBTs, freewheeling diodes, gate drive, under-voltage and over-current protection into one DIP module with isolation and creepage already engineered, removing driver design and layout debugging. Listed IGBT-based IPMs are 600V class, rated 6A~30A with 12A~60A peaks — the range of air-conditioner and washer inverter boards. The trade-off: drive timing and gate-resistor knobs are fixed and protection thresholds preset, so check the application level against actual conditions; only high-power or unusual topologies go back to discrete parts.
18IGBT threshold voltage is higher than a MOSFET’s — how should the gate-drive levels be set?
Listed discrete IGBTs have Vth of about 4.0V~6.5V, and datasheet VCE(sat) is specified at VGE=15V. Drive the gate to that test voltage; MOSFET-style levels give incomplete turn-on and a VCE(sat) off spec. For turn-off stay below the Vth minimum, with a negative bias for margin against false turn-on. Size drive current from gate charge: listed isolated drivers span 3.0/6.0A to 12.0/12.0A, with source and sink checked separately.
19RC-IGBT or IGBT + FRD inside an IPM — how to choose?
Check the current tier first: pick ICP (listed about 12A~60A) from motor start-up and stall peaks, not rated power alone. Then the structure: RC-IGBT is reverse-conducting with higher integration; IGBT&FRD uses a separate freewheeling diode whose recovery behavior can be chosen on its own. Freewheel-side VF of about 1.5V~2.35V and Trr of about 0.15~0.3μs set freewheeling loss and commutation EMI — weigh them by carrier frequency and EMI targets. The two are not drop-in equivalents; re-evaluate recovery behavior when swapping.