Application Perspective

Given the wide availability of high-voltage power IGBTs and MOSFETs with breakdown voltage ratings ranging from 500V to 800V, designers are often faced with the challenge of selecting the most suitable device for a specific application and set of operating conditions. Choosing between an IGBT and a MOSFET requires careful consideration of performance, efficiency, switching behavior, and overall system requirements.

In the case of three-phase variable-speed motor drives with rated power levels between 300W and 5kW, using a DC bus voltage in the range of 300V to 400V and typically implemented with a six-switch topology, 600V to 650V IGBTs have traditionally been the preferred choice from an overall performance perspective. These IGBTs are commonly co-packaged with anti-parallel fast recovery diodes, providing robust switching performance and reliable operation in motor drive applications.

However, the availability of high-speed power MOSFETs with voltage ratings between 500V and 650V, low on-state resistance RDS(on), and relatively fast body diode recovery characteristics has raised an important question. With these improvements in MOSFET technology, designers are increasingly considering whether it is time for MOSFETs to replace IGBTs in certain power ranges and applications.

This shift depends on factors such as switching frequency requirements, efficiency targets, thermal performance, and cost considerations. As MOSFET technology continues to advance, the boundary between traditional IGBT and MOSFET application domains is becoming less defined, prompting designers to carefully re-evaluate device selection for modern power electronics systems.