AC/DC POWER TOOL
DRIVE
November 7, 2019
A power tool is provided with a multi-phase brushless motor including a rotor and a stator having stator windings corresponding to at least three phases of the motor. A power switch circuit is provided including high-side and low-side power switches. A power supply interface receives alternating-current (AC) power from an AC power supply or battery direct-current (DC) power from one or more battery packs. A rectifier converts the AC power to a rectified DC voltage on a bus line. A capacitor is disposed across the bus line such that, within each half cycle of the AC power voltage waveform, the power switch circuit draws current from the AC power supply within a first time period and from the capacitor within a second time period, the capacitor having a capacitance value such that the first time period is greater than the second time period.
Discussion in the ATmosphere