Transient hygro-thermal-response of power modules in inverters – mission profiling for climate and power loading

Conference: CIPS 2014 - 8th International Conference on Integrated Power Electronics Systems
02/25/2014 - 02/27/2014 at Nuremberg, Germany

Proceedings: ETG-Fb. 141: CIPS 2014

Pages: 8Language: englishTyp: PDF

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Bayerer, Reinhold; Lassmann, Matthias; Kremp, Sebastian (Infineon Technologies AG, Germany)

The number of outdoor applications of power electronics is growing. Therefore mission profiling with respect to climate conditions has become a new field of interest. The response of moisture inside power electronics can be simulated by the use of an equivalent circuit. It consists of variable and controlled resistors and capacitors to describe diffusivity, permeability and storage in polymers. Here voltages represent the concentration of water in air or polymers. Such R-C networks allow the 2-D and 3-D effects to be describe as well. The coupling to the thermal equivalent networks can be done by voltage outputs, e. g. temperatures. The coupled thermal- and hygro-sub-circuit lead to the overall hygro-thermal equivalent circuit. This circuit allows simulating moisture levels based on climate conditions and heating due to operation of power electronics. Examples demonstrate the possibility that humidity inside power boxes exceeds the ambient conditions due to the desorption of moisture from the heated polymers. It is also demonstrated that condensation of water can occur during day and night cycles. Failure models need to be established to conclude with lifetime calculations based on this method.