Electric power tool and method for driving brushless motor thereof
US10256701B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 2018 |
| Grant date | Apr 9, 2019 |
| Priority date | — |
| Expiry date | Feb 26, 2038 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K7/145
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric power tool and a method for driving a brushless motor in the electric power tool. The electric power tool includes a driving circuit for driving the brushless motor and position sensors (D1, D2, D3) for detecting positions of the rotor. The rotor of the brushless motor, when rotating in a normal direction, sequentially passes by a commutation position, where a signal of at least one of the position sensors (D1, D2, D3) in the brushless motor changes, and a reference position, where a back electromotive force of the stator winding of at least one phase in the brushless motor is at a midpoint position of the waveform of the back electromotive force. An electrical angle between the commutation position and the reference position ranges from 20° to 40°. The position sensors (D1, D2, D3) are configured such that performance of the brushless motor is improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.