In-situ health monitoring of IGBT modules of an on-line medium-voltage inverter system using industrial Internet of Things

Requirements of the Internet of things for the network includes the ability to monitor the equipment and devices. Nowadays, the reliability of a power electronics converter has raised concerns of both academia and industry. In particular, power semiconductor devices are continuously exposed to excessive stress while being designed with high power handling capability and are considered as the most fragile component in power converters suffering from a high failure rate. Aiming to find an effective monitoring method which is also helpful for the Internet of Things and improve the reliability of a three-level neutral-point-clamped power inverter, an in-situ health monitoring method is proposed by harnessing the inverter operational characteristics and degradation sensitive electrical parameters to address the IGBT wire bonding faults. The zero voltage state provides an inherent redundant feature that allows for a power switch to be diagnosed during its normal operation in a neutral-point-clamped power inverter. The proposed prognostic approach obtains both the wire bonding failure features and junction temperature from the terminals of an IGBT module, which is regarded as non-invasive on-line health monitoring. The system performance can be affected by the designated testing point and testing window, which is discussed and experimentally validated. The proposed technique allows unhealthy wire bonding in IGBT modules online monitoring during the operational period of the inverter. And the proposed in-situ health monitoring of IGBT modules can be used for the industrial Internet of things.