Method and apparatus for fine resolution brushless motor control
US6744230B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 2002 |
| Grant date | Jun 1, 2004 |
| Priority date | — |
| Expiry date | Oct 29, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/17
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A motor controller (30) includes three analog Hall-effect sensors (42, 44, 46) for forming continuous-time signals proportional to the sine and cosine of the position of the rotor (24) of a motor (20). The sine and cosine signals are differentiated to obtain signals proportional to the rotor rate times the sine and cosine values. These integrated values are then multiplied by the cosine and inverse of the sine values, respectively, to obtain values equal to the rotor rate times the square of the cosine and the rotor rate times the square of the sine. These latter two values are summed to obtain an output signal proportional to the rotor rate based on the trigonometric identity sin2(x)+cos2(x)=1. Since the motor controller (30) derives a high-resolution value for the rotor rate, it may be used for fine resolution control of brushless motors and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.