How to include the dependency of the RDS(on) of power MOSFETs on the instantaneous value of the drain current into the calculation of the conduction losses of high-frequency three-phase PWM inverters

In this paper, the conduction losses of power MOSFET’s are calculated analytically for application in three-phase voltage dc-link pulsewidth modulation (PWM) converter systems. Contrary to a conventional calculation, the dependency of the turn-on behavior on the drain current is considered in terms of a quadratic approximation. The derived relationships are represented graphically; they can be included directly into the dimensioning of the power transistors.