Nonadjacent Demagnetisation Detection in Direct‐Drive Permanent Magnet Generators for Renewable Energy Systems

ABSTRACT Advancement of renewable energy technologies placed tidal, wave and wind energy systems at the forefront of sustainable power generation. Permanent magnet synchronous generators with high efficiency, modularity, and low power consumption, such as the lightweight and modular C‐GEN design, have been applied successfully in these applications. The demagnetisation condition of nonadjacent magnets in direct‐drive permanent magnet generators is investigated, and different diagnostic approaches are evaluated. It is shown that nonadjacent demagnetisation can produce false negative diagnostic alarms when familiar condition monitoring methods such as the MCSA are applied. It presents solutions for faulty magnet detection of permanent magnet generators for tidal, wave, and wind energy harvesting, supported by numerical analysis and experimental testing. It is particularly novel that demagnetisation in two nonadjacent magnets is investigated here, something not previously considered.