Patent ID: 8421255

Claim:
A system for determining a temperature of a permanent magnet in a machine, comprising: a. a voltage sensor, wherein the voltage sensor generates at least one voltage signal reflective of a voltage potential across a stator; b. a current sensor, wherein the current sensor generates at least one current signal reflective of a current flow through the stator; and c. a processor that receives the at least one voltage signal and the at least one current signal, converts the at least one voltage signal and the at least one current signal to an effective voltage constant signal, converts the at least one current signal to an actual current signal referenced to a rotor in the machine, generates a reference voltage constant signal based on the actual current signal, wherein the reference voltage constant signal reflects a reference temperature of the permanent magnet in the rotor, and generates a temperature signal reflective of the temperature of the permanent magnet in the machine based on the ratio of the effective voltage constant signal and the reference voltage constant signal.