Apparatus and method for providing a signal proportional to flux in an AC motor for control of motor drive current
US4280085A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1979 |
| Grant date | Jul 21, 1981 |
| Priority date | — |
| Expiry date | Apr 24, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for providing signals indicative of the magnitude and angular position of the DC motor flux of an AC induction motor is disclosed. The AC induction motor provides controllable rotation and torque in accordance with a drive current of variable magnitude and frequency. A first signal is provided proportional to the rate of change of the flux of the motor. A second signal is supplied proportional to the magnitude of the drive current. A flux signal is generated proportional to the integral of the first signal when the frequency of the output signal is above a preselected value and which is proportional to the second signal when the frequency of the output signal is below the preselected value. A representative value for the preselected frequency value is 3 Hertz in a 60 Hertz drive system. The flux signal is effective to control the generation of the drive current. An embodiment of the present invention is shown for the case where the motor is stopped at a predetermined position in accordance with a predetermined conduction state of the inverting supplying the drive current. Additional embodiments are shown for the general cases where the motor can be stopped a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.