Turn-to-Turn Converter Stress Impact on the Lifetime of Rotating Machines

The effects of turn-to-turn converter stresses on the lifetime of Litz wires samples have been investigated. Three-level low duty waveshapes have been used to produce a voltage simulating the one appearing during operation. Under such waveform a higher partial discharge inception voltage was recorded. However, no significant improvement in endurance times under discharge was observed, likely due to PD events occurring predominantly at the waveform flanks in converter operation. Corona resistant materials can only partially alleviate the issue, hence PD-free design approaches may be required in many circumstances.