System and method for monitoring temperature of rotating electric machine

A system for monitoring temperature of a rotating electric machine, comprising:

• a coil that has a strand for passing a current through the coil forming part of the rotating electric machine, and an insulating layer placed around the strand;
• at least one in-coil temperature sensor that is placed within the coil;
• a physical quantity sensor that is placed within the rotating electric machine and measures a physical quantity related to operation of the rotating electric machine;
• a sensor data storage that stores values measured by the at least one in-coil temperature sensor and the physical quantity sensor;
• an in-machine temperature predictor that predicts a temperature inside the rotating electric machine by use of the value measured by the physical quantity sensor and stored in the sensor data storage;
• a strand temperature calculator that calculates a relationship between a temperature of the strand and a temperature measured by the at least one in-coil temperature sensor, on the basis of the temperature inside the rotating electric machine predicted by the in-machine temperature predictor;
• and
• a strand temperature predictor that predicts a temperature of the strand from the value measured by the at least one in-coil temperature sensor and stored in the sensor data storage, and from the relationship between a temperature of the strand and a temperature measured by the at least one in-coil temperature sensor calculated by the strand temperature calculator.