New Experimental System and Procedure for On-Line Insulation Life Testing of Stator Winding of Automotive Traction PMSM Without Using Dynamo System

This paper proposes an experimental procedure using a new experimental system for on-line insulation turn-to-turn life testing of a stator winding without a rotor of a permanent magnet synchronous motor. Without using any expensive large capacity dynamo set-up, the proposed system and procedure make it possible to test the insulation life of the stator winding under steady state operation of the motor even though at high temperatures of more than 200 °C. The line-to-line surge voltage applied to the motor under the inverter's PWM control at the running state of the motor is successfully replicated by the proposed static system. Suitable control blocks are given to describe the experimental procedure for an automotive traction application. In the new experimental set-up, a twisted pair (TP) winding is connected between the U-V phase of the stator phase windings. The turn-to-turn insulation life of the TP windings is approximately estimated by measuring the capacitance of the TP windings at regular time intervals during the on-line testing. Finally, an experiment is carried out to detect the partial discharge in the TP windings and understand the physical relationship that exists between the total partial discharge count number and the decrease in capacitance of the TP windings after a specified time-period of insulation life testing.