Tip of the day

Current overload capacity of power electronic systems

Every user wishes to have sufficient current safety margin in the power electronics system so that overall plant has long life with minimum failures. One often finds percentage overload requirements mentioned in the specifications and offers.

One must be careful in interpreting data sheets of individual semiconductor, nominal current ratings of the unit and overload capacity.

Real overload capacity depends upon the margin in junction temperature and not only on the absolute value of current and datasheet ratings. This means junction temperature at nominal current, heat transfer from junction to final cooling medium and maximum allowable operating junction temperature defines the actual overload capacity.

This method should help in evaluating overload capacity.