Low-speed sensorless brushless motor control in a power tool
US11171586B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2020 |
| Grant date | Nov 9, 2021 |
| Priority date | — |
| Expiry date | Apr 21, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2209/07
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power tool is provided including a brushless motor having a stator defining a plurality of phases, a rotor rotatable relative to the stator, and power terminals electrically connected to the phases of the motor. A power unit is provided including power switches. A control unit is interfaced with the power unit to output a drive signal to one or more of the motor switches to drive the phases of the motor over a series of sectors of the rotor rotation. The control unit is configured detect incorrect rotation of the rotor by applying a first series of voltage pulses to a present sector and a second series of voltage pulses to a previous sector, measuring motor currents associated with the first and second series of voltage pulses, and comparing corresponding motor current measurements to detect a transition from the present sector to the previous sector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.