Prognostics of Power Electronic Converters in renewable energy systems: an approach based on acoustic emission measurement and thermal modelling

Bolourinejad, Pouria (2024) Prognostics of Power Electronic Converters in renewable energy systems: an approach based on acoustic emission measurement and thermal modelling. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Renewable energy conversion systems play an important role in delivering energy from natural resources. Power Electronic Converters (PECs) are vital for efficiently conditioning the generated energy to align with the requirements of the source. One of the obstacles in the wide adaptation of renewable energies is the lack of efficiency and reliability in these systems. In wind turbines, Electrical circuits, including the PEC, contribute to 24% of total failures experienced by the system. One of the key components in a PEC is the Insulated Gate Bipolar Transistor (IGBT) which is used as a switching device in PECs. They occur due to different factors such as operating conditions, environmental factors (temperature and humidity) and the internal structure of the IGBTs which are formed of layers of different material with different properties. This research focuses on exploring the relationship between the changes in temperature of the IGBT chip with acoustic emissions signals. The aim of this research project is the development of a more cost-effective method for condition monitoring and prognostics of PECs. In this thesis, a thorough literature review of current condition monitoring schemes is provided and the gap in research is identified. A great number of scholars and experts have experimented with the AE in PECs however the link between the increase in temperature of this chip and the fluctuations in AE signals is not yet established. Under certain loading conditions, the temperature of IGBT chip changed from the ambient temperature (20℃) to 55℃. The acoustic emissions were measured in 5℃ intervals and it was discovered that after the temperature surpasses the 40℃ mark, the AE signal amplitude drops to 0.1 percent of its value at 20℃. Moreover, the rising temperature creates new peaks in the frequency domain at frequencies between 400-600 kHz.