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US 5,473,232 AGranted
Sensorless brushless motor driving apparatus with induced voltage signal latch
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsSatoshi Tamaki, Yasuhiro Kondo
Life of this patent
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Abstract
In a driving apparatus for a sensorless brushless motor, changing-over of excitation is executed at every electric angle of 30.degree. from a trigger point defined by a signal obtained by latching an induced voltage at the time of fall-down of the pulse-width modulation signal.
Claims4
A driving apparatus for a sensorless brushless motor, comprising:
- a microprocessor;
- drive means for driving said motor in accordance with an excitation signal issued from the microprocessor;
- speed control means for controlling a speed of said motor by pulse-width modulating the excitation signal;
- latch means for latching a converted signal representative of an induced voltage appearing on a coil of said motor in comparison with a neutral point voltage of said motor, the latch means latching the converted signal according to a pulse width modulation signal issued from the microprocessor;
- and
- correction means for correcting an excitation time period of said excitation signal by referring to the latched converted signal.
3 more elements
Dependencies are inferred from the claim text.