Brushless DC motor without a position sensor
US5378976A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 12, 1993 |
| Grant date | Jan 3, 1995 |
| Priority date | — |
| Expiry date | Apr 12, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/20
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A brushless DC motor detects a positional relationship between the rotor and the stator windings in a short period of time when starting the motor and immediately switches the mode from a phase coincidence mode at the time of starting to a normal position detecting mode performed by counting output pulses in response to the rotational speed of the rotor. The motor detects a position of the rotor at an extremely high accuracy independently of the magnitude of the load even when the motor has already been subjected to the application of such a load at the time of starting. The motor is always driven at a high efficiency by applying a phase correction process so as to cause the phase of each of the voltages respectively induced in the stator windings to coincide with the corresponding one of the driving currents respectively outputted to the stator windings when the motor is being rotated normally.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.