Verification of the Current Load Capacity of The MOSFET Transistor for Low-Voltage Application Using Temperature Estimation
Jan Štěpánek, Bedrich Benar, Pavel Drábek · 2019
This paper deals with the verification of the maximum current rating of MOSFET transistors in a discrete package TO-247AC. The main motivation for this analysis was the redesign of AC power drive chain for electric go kart with three phase power converter of the output nominal power 10kW, a supply voltage 48V and minimal switching frequency 50kHz. The inverter must be able to operate with short-term current overload up to 450A. A parallel combination of three power transistors is used to design the basic power switch. The HEXFET Power MOSFET transistor (IRFP4468PdF in a discrete case TO-247AC) was chosen as a basic structural element. We used DC analysis to verify the properties and limits of the discrete case TO-247AC. The maximum rated current through the MOSFET transistor was determined with respect to the maximum chip temperature and enclosure limitation. In order to accurately verify the measuring results of transistor temperature, a thermo-camera was used (the color is used to define the emissivity of measured object with reference ε = 0,9). Temperature was also measured by a thermometer PT100 sensor and estimated from the forward voltage on freewheeling diode.