Technique for controlling brushless motor of electric work machine
AssigneeMakita Corporation
InventorMasayuki OKAMURA
Life of this patent
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Abstract
One aspect of the present disclosure provides an electric work machine including a brushless motor, multiple positive-side conduction paths, multiple negative-side conduction paths, multiple high-side switches, multiple low-side switches, and a control circuit. The control circuit performs a conduction control and a current-delivery restriction. The conduction control includes turning on a driven pair according to a first conduction pattern each time an update timing arrives. The current-delivery restriction includes suspending the conduction control to thereby restrict or stop delivery of an electric power to the brushless motor, based on elapse of a limit time without arrival of a next update timing since arrival of the update timing.
Claims18
An electric work machine comprising:
- a brushless motor (i) including multiple terminals and (ii) configured to drive a driven tool, the driven tool being fixed to the electric work machine or configured to be detachably attached to the electric work machine;
- multiple positive-side conduction paths each electrically coupling a corresponding one of the multiple terminals to a positive electrode of a DC power source;
- multiple negative-side conduction paths each electrically coupling a corresponding one of the multiple terminals to a negative electrode of the DC power source;
- multiple high-side switches each (i) on a corresponding one of the multiple positive-side conduction paths and (ii) configured to complete or interrupt the corresponding one of the multiple positive-side conduction paths;
- multiple low-side switches each (i) on a corresponding one of the multiple negative-side conduction paths and (ii) configured to complete or interrupt the corresponding one of the multiple negative-side conduction paths;
- and
- a control circuit configured to perform:
- a conduction control, the conduction control including, each time an update timing arrives, turning on a driven pair corresponding to a rotation angle of the brushless motor according to a first conduction pattern to thereby deliver a first electric power to the brushless motor from the DC power source through the driven pair, the update timing arriving each time the brushless motor rotates by a reference rotation angle, the driven pair including two switches, the two switches being one of the multiple high-side switches and one of the multiple low-side switches, and
- a current-delivery restriction, the current-delivery restriction including suspending the conduction control based on occurrence of a first abnormality during performance of the conduction control to thereby restrict or stop delivery of the first electric power to the brushless motor, the first abnormality including elapse of a limit time without arrival of a next update timing since arrival of the update timing.
A method for controlling a brushless motor of an electric work machine, the method comprising:
- driving a driven pair corresponding to a rotation angle of the brushless motor according to a conduction pattern each time an update timing arrives, the update timing arriving each time the brushless motor rotates by a reference rotation angle, the driven pair including, of multiple switches, two switches corresponding to the rotation angle, the multiple switches each being on a corresponding one of multiple conduction paths electrically coupling the brushless motor to a DC power source;
- and
- suspending driving of the driven pair according to the conduction pattern based on a limit time having elapsed without arrival of a next update timing since arrival of the update timing.
Dependencies are inferred from the claim text.