Further, a detailed characterization of various devices at
different operating conditions (V, I and T) taking into
account loop inductance and detailed circuit models of test
fixtures was performed. Using the characterization data,
device loss models were extracted and represented as
polynomial functions of V, I and T. These loss models were
compared with traditional datasheets and it was proved that
linear interpolation/extrapolation of loss data with voltage
cannot be used for designing high efficiency direct AC/AC
power converters. As the errors resulting from linearly
extrapolating switching losses with the operating conditions
could be as large as 202%. Therefore, a justification was given for the need for characterizing devices under variable
operating conditions.