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US 7,605,556 B2Granted
Microcontroller methods of improving reliability in DC brushless motors and cooling fans
AssigneeMinebea Co., Ltd.
InventorsScott Frankel, Eric Hardt, Nigel D. Strike
Life of this patent
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Abstract
A method of controlling a motor speed for a fan assembly includes receiving a duty cycle value at a microcontroller. The microcontroller receives a measured fan speed from a speed sensor. An expected fan speed is determined, where the expected fan speed corresponds to the duty cycle value. The measured fan speed is compared with the expected fan speed. A duty cycle of a motor driving signal is reduced if the measured fan speed is less than a predetermined fraction of the expected fan speed.
Claims9
A method of controlling a motor speed for a fan assembly, comprising:
- receiving a duty cycle value at a microcontroller;
- operating a motor of the fan assembly with a motor drive signal having a duty cycle substantially equal to the received duty cycle value;
- receiving a measured fan speed from a speed sensor;
- determining an expected fan speed based on the duty cycle value, wherein the expected fan speed is an expected speed of the motor when the motor is driven by the motor driving signal;
- comparing the measured fan speed with the expected fan speed;
- and
- reducing the duty cycle of the motor driving signal if the measured fan speed is less than a predetermined fraction of the expected fan speed.
4 more elements
Dependencies are inferred from the claim text.