Patent ID: 9575104
Date: 2017-02-21
CPC Classifications: G01K,G01R

Claim:
1. A method for estimating at least one of resistance and temperature of a winding of an electrical machine while the machine is operating, the method comprising: energising the winding to cause a unidirectional current to flow in the winding to operate the machine, the unidirectional current and a resulting winding voltage across the winding each having a low-frequency component with a frequency content below a limit frequency and a high-frequency component with a frequency content above the limit frequency; deriving a first signal indicative of a magnitude of the low-frequency component of the winding voltage; deriving a second signal indicative of a magnitude of the low-frequency component of the unidirectional current; and deriving a third signal indicative of at least one of resistance and temperature of the winding using the first and second signals.