Apparatus and method for monitoring magnet flux degradation of a permanent magnet motor
US10295599B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 2017 |
| Grant date | May 21, 2019 |
| Priority date | — |
| Expiry date | Aug 11, 2037 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/64
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method in a motor controller for an electric motor is disclosed. The method includes receiving a motor current measurement, a motor reference voltage or measured voltage, and an estimated temperature from the electric motor, determining a reference flux linkage estimate (λpm,ref) from a lookup table based on the motor current measurement and the estimated temperature, determining a back-EMF (electromotive force) estimate based on the motor current measurement, the motor voltage and the estimated temperature, determining an observed flux linkage estimate (λpm,obs) from the back-EMF estimate, determining a magnetic strength as a ratio of the observed flux linkage estimate to the reference flux linkage estimate, and determining that a rotor magnet has been demagnetized to an unacceptable level when the magnetic strength is below a threshold level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.