guides

Selecting Power Discretes for Motor Drive and Power Conversion Applications

Robert Kim

Senior FAE - Power Electronics

2026-03-10

Technical guide for selecting ST power discretes including MOSFETs, IGBTs, and SiC devices for motor control, power supplies, and renewable energy applications. Covers device selection, gate drive design, and thermal management.

Design considerations include electrical specifications, thermal management, and application-specific requirements. Refer to the product documentation for detailed parameters.

For specific application requirements and design assistance, contact st's technical support team or refer to the official product documentation and reference designs.

💡 FAE Insights

⚠️ Common Pitfalls

✗ Insufficient gate drive voltage leading to high Rds(on)
✗ Inadequate thermal design causing overtemperature shutdowns
✗ Ignoring parasitic inductance causing voltage overshoots
✗ Using IGBTs at frequencies above their optimal range
✗ Insufficient voltage margin leading to avalanche failures

📋 Customer Cases

Solar Inverter Manufacturer

Renewable Energy

Residential String Inverter

Challenge

Customer's 5kW solar inverter was achieving only 96.5% efficiency, below the 98% target required for market competitiveness. The design used silicon IGBTs at 16kHz switching frequency.

Solution

Redesigned with ST SiC MOSFETs (SCTW90N65G2V) at 32kHz switching frequency. Reduced switching losses by 70% despite higher frequency. Optimized gate drive with 18V turn-on and -3V turn-off.

Results

Efficiency improved to 98.2%, exceeding target. Heatsink size reduced by 60%, saving $15 in BOM cost. Product became market leader in efficiency ratings and won major distributor contracts.