Brushless direct-current motor and control for power tool
US9197146B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2013 |
| Grant date | Nov 24, 2015 |
| Priority date | — |
| Expiry date | Nov 6, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P29/0241
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Brushless direct-current (“BLDC”) motor and control for a power tool. A BLDC motor of a power tool is controlled in either a pulse-width modulation (“PWM”) commutation mode or a centerline commutation mode. When the motor is rotating slowly, the motor is operated using PWM commutation. When the motor is rotating at a speed greater than a threshold speed value, the operation of the motor is transitioned to the centerline commutation mode. When operating in the centerline commutation mode, the high-side field-effect transistors (“FETs”) and low-side FETs can each be used for motor speed control. By switching between speed control using the high-side FETs and speed control using the low-side FETs, the heat generated by freewheeling currents can be approximately evenly distributed among the high-side and low-side FETs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.