Step motor control
US4734631A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 1986 |
| Grant date | Mar 29, 1988 |
| Priority date | — |
| Expiry date | Jul 22, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P8/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A step motor control system which can control a step motor to rotate at a variable high speed like a brushless motor. A position signal indicating a position of a rotor of a step motor relative to a specific one of field windings is detected as a voltage signal which is successively compared with a reference voltage in order to detect a specific angular position of the rotor at which selective energization and deenergization of the field windings are started for a next stepping operation of the motor. The position signal may be extracted as a voltage signal from an electric current flowing through a last energized field winding by a resistor connected thereto. From the voltage signal, a back EMF induced in the field winding due to its self inductance is subtracted to detect a voltage position signal or EMF induced in the field winding by a permanent magnet of the rotor. The back EMF is produced by an electronic simulation means including an integrating circuit having a same time constant with the field winding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.