The relationship between the reliability and cost of converters is quantiﬁed by the junction temperature and chip numbers of power switching devices, respectively, in this special topic. It is proved that the conduction loss, switching loss, and thermal impedance models of power switching devices (IGBT module) can be included with chip number information. A simpliﬁed analytical solution which directly extracts the junction temperature mean value Tm and fluctuation ΔTj is proposed. The proposed reliability-cost model is demonstrated on a 10 MW 3L-NPC wind power inverter as case study.
With the developed reliability-cost proﬁle for the given converter solution, it is possible to enable more accurate and cost-effective design for wind power converter achieving the target reliability performance, and it is also possible to unify and compare different converter solutions in a more sensible way.