ESTIMATION OF RESISTANCE IN ELECTRICAL MACHINES

摘要

In an electrical machine which has unidirectional excitation applied to its windings, the mean values of voltage and current can be computed from the instantaneous phase voltage and current by the use of, for example, low-pass filters (in either the analogue or digital domain). The value of winding resistance can then be calculated by dividing the mean voltage by the mean current. This avoids the cost, fragility and potential inaccuracy of conventional temperature sensors, and provides the controller with an ongoing estimate of winding temperature.

主权项

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; deriving a third signal indicative of at least one of resistance and temperature of the winding using the first and second signals.