Evaluation on Insulation Performance of Traction Motors for a Hybrid Vehicle by Partial Discharge Measurement

This paper dealt with the insulation evaluation by a measurement of partial discharge(PD) on traction motors used in a hybrid vehicle. The PD method has been accepted as an effective and a non-destructive. technique to evaluate insulation performance of low-voltage electric and electronic devices. In this paper, the PD measurement system which was manufactured with a coupling network, a low noise amplifier, and an associated electronics is described. The PD measurement system has the frequency bandwidth of at -3 [dB] and the stable sensitivity of 19 [mV/pC] for the traction motor. From the experimental results, discharge inception voltage (DIV) and apparent charge (q) were and 105 [pC] for the used motor, and and 84 [pC] for the new one. By comparing the DIV and q, we could evaluate the insulation condition for the traction motors.