Temperature cycling of low voltage motor drives

Motor drives are used in a wide range of industrial applications, many of which impose high reliability demands on the electronics used in them. Moreover, the environmental conditions in industrial applications may vary a lot and therefore reliability studies for the motor drives are essential. In this study the reliability of a low voltage motor drive was studied with two different temperature cycling profiles. The results of the study showed that temperature cycling triggered some reversible device faults during testing, but catastrophic IGBT failures, common for power electronics, were less seen. More detailed analysis suggests that the reason for the device faults may have been cracks in the solder joints of the pinheader connector between two PCBs of the device, or fretting corrosion on the connector contact materials.