Energy recycle on power tools

Patent metadata

Field	Value
Publication number	US-2018370010-A1
Application number	US-201816019846-A
Country	US
Kind code	A1
Filing date	Jun 27, 2018
Priority date	Jun 27, 2017
Publication date	Dec 27, 2018
Grant date	—

Abstract

A power tool with an energy recovery function including a casing, a brushless motor located within the casing, a battery pack connected to the casing, and a switching circuit. The brushless motor is used for driving a working part. The battery pack is connected to the brushless motor via the switching circuit. The switching circuit is configured to allow a first part of the braking energy from the brushless motor to be recovered to the battery pack by controlling on/off of the switching circuit when the brushless motor tends to be stopped during rotation. When the controller of the power tool detects a need to decelerate/stop the motor, the service time of the battery is prolonged by recharging a part of the energy back to the battery through controlling the circuit dynamic and adjusting the on/off duty cycle of the circuit.

First claim

1 - 7 . (canceled)

8 . A power tool serving an energy recover function, the power tool comprising:
a casing; a brushless motor located within the casing and configured to drive a working part; a battery pack connected to the casing; and a switching circuit; wherein the battery pack is connected to the brushless motor through the switching circuit, and the switching circuit is configured to allow a first part of a braking energy from the brushless motor to be recovered to the battery pack by controlling the on/off of the switching circuit when the brushless motor is stopped during rotation.

9 . The power tool of claim 8 , further comprising a controller connected to the switching circuit for controlling the on/off of the switching circuit.

10 . The power tool of claim 9 , wherein the controller is configured to control a duty cycle of the on/off of the switching circuit so as to allow the first part of the braking energy to be recovered to the battery pack in a form no higher than the maximum permitted voltage.

11 . The power tool of claim 9 , wherein the controller is configured to control a duty cycle of the on/off of the switching circuit so as to allow the first part of the braking energy to be recovered to the battery pack in a form no higher than the maximum permitted current.

12 . The power tool of claim 9 , wherein the controller controls the on/off of the switching circuit through a pulse width modulation signal.

13 . The power tool of claim 9 , wherein a second part of the braking energy in the brushless motor is dissipated in a form of heat by the controller controlling the duty cycle.

14 . The power tool of claim 8 , wherein the switching circuit includes six switching elements; the brushless motor being a three-phase motor, each phase of which being connected to positive and negative electrodes of the battery pack respectively through two said switching elements.

15 . The power tool of claim 14 , wherein the switching elements are MOSFETs.

16 . The power tool of claim 14 , wherein the switching elements are IGBTs.

17 . The power tool of claim 8 , wherein the battery pack is removably mounted to the casing.

Assignees

• Tti Macao Commercial Offshore Ltd

Inventors

• Xie Li Hua
• Li yong min

Classifications

• H01M50/247

  specially adapted for portable devices, e.g. mobile phones, computers, hand tools or pacemakers · CPC title

• B25F5/00 Primary

  Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M10/6235

  Power tools · CPC title

• H01M2/1022

  Electricity · mapped topic