Systems and methods for torque control of actuator and brushless DC motor therein
US5847530A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 28, 1997 |
| Grant date | Dec 8, 1998 |
| Priority date | — |
| Expiry date | Aug 28, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A brushless DC motor is controlled by determining a speed of the motor and a line voltage supplying drivers of the motor. Based upon these determined values and predetermined motor performance data, a maximum PWM on-time is determined for drive signals supplied to windings of the motor. This maximum PWM on-time thereby limits motor torque output to a predetermined maximum. Stopping the motor is performed in sequential phases including a loaded generator phase, an active braking phase and a holding phase. During holding, the amount of energy supplied to the motor is reduced to the point just before slippage such that holding energy is minimized. Upon power failure, the motor is driven toward a spring return home position overcoming static friction that may prevent the spring return mechanism from functioning properly. These techniques are applied to a motor in an actuator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.