Waveform shaping in power tool powered by alternating-current power supply
US11173584B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 2019 |
| Grant date | Nov 16, 2021 |
| Priority date | — |
| Expiry date | Oct 19, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2207/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power tool is provided including a brushless DC (BLDC) motor, a rectifier that receives an alternative current from a power supply and outputs a rectified signal supplied to a DC power bus, and an inverter circuit having motor switches connected electrically between the DC power bus and the motor. A control module controls a switching operation of the power switches to regulate supply power from the power supply to the motor. The control module controls the switching operation so as to, within a half cycle of the AC power supply voltage waveform, increase current draw from the power supply from a first threshold at or after a first zero-crossing of the half cycle up to a second threshold, and reduce current draw from the power supply from the second threshold up to a third threshold at or prior to a second zero-crossing of the half cycle.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.