Search Coil Based Detection of the Inter-Turn Short Circuits in Aircraft Permanent Magnet Synchronous Machine by Signal Frequency Extraction

This paper demonstrates a new methodology towards the reliable detection of the inter-turn short circuits in surface-mounted permanent magnet synchronous machines specially designed for aviation applications. The diagnostic strategy deploys search coil based condition monitoring in conjunction with a frequency extraction algorithm for the detection and evaluation of stator fault-related harmonics. The discussed approach is investigated on a 42 kW PM machine, with a double layer tooth coil winding with the help of Finite Element simulations. The impact of the inter-turn fault is investigated at different operating conditions, notably rotational speed and PWM frequencies, thus enabling the investigation and identification of harmonics that show compelling diagnostic potential for detecting the fault even at incipient severity levels.