Reliability and Ageing of Insulated Metal Substrate PCBs in High-Voltage Power Electronic Applications
G.W. Lagerweij (TU Delft - Electrical Engineering, Mathematics and Computer Science)
M. Ghaffarian Niasar – Mentor (TU Delft - High Voltage Technology Group)
P.T.M. Vaessen – Graduation committee member (TU Delft - High Voltage Technology Group)
J. Dong – Graduation committee member (TU Delft - DC systems, Energy conversion & Storage)
Joost van Straalen – Mentor (Prodrive Technologies)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Insulated metal substrate (IMS) printed circuit boards (PCBs) are an attractive alternative to conventional FR4-based PCBs and power modules due to their good thermal performance, low cost, and compatibility with the reflow soldering processes. In this thesis, the dielectric performance of IMS PCBs is characterised to validate their use in high-voltage power electronic applications and ensure that an acceptable lifetime and reliability can be reached. In particular, the high-frequency degradation of the dielectric is investigated.
The IMS dielectric was characterised using breakdown tests with various voltage waveforms and frequencies to closely approximate their use-case in power electronic converters. Two high-voltage generators were designed and realised to generate high-frequency square-wave and sinusoidal waveforms. In addition, diagnostic tests were performed to identify the effect of electrical ageing on the dielectric properties.
he designed high-voltage test sources allowed for ramp breakdown and lifetime tests up to 100 kHz and 10 kVpk. These tests showed that the dielectric degrades extremely fast under high-frequency voltage stress, most likely due to localised high partial discharge activity and electrical treeing. As a result, no reasonable lifetime can be expected when operating above the discharge inception voltage. For thick dielectrics (>100 µm), surface discharges are the dominant degradation mechanism with an inception voltage of 2.4 kVpk. The maximum nominal voltage should be limited to approximately 1.5 kVpk to ensure the reliable operation of the IMS PCBs.