Magnetic drive control system for a multiple cooling fan installation
First Claim
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1. A motor vehicle cooling fan drive apparatus comprising:
- first and second juxtaposed and magnetically coupled rotary cooling fans;
drive means including an electric motor connected to rotatably drive said first cooling fan, and motor controller means connected to said electric motor for controlling its running speed in accordance with the value of a speed command signal applied thereto; and
system control means including means for (1) generating a desired speed value for said fans in accordance with the vehicle cooling demand, (2) determining a phase error EP according to the relative rotary positions of said first and second fans, (3) adjusting said desired speed value in a direction to reduce said phase error EP at least when said phase error is greater than a threshold error, and (4) applying a speed command signal to said motor controller means in accordance with the adjusted speed value, thereby to control said electric motor for synchronously accelerating and running said first and second fans at said desired speed value.
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Abstract
A multiple cooling fan installation in which a master fan is driven by a brushless electric drive motor, and at least one slave fan having blades positioned adjacent the blades of the master fan is driven by magnetic coupling between such adjacent blades. Synchronism of rotation between the master and slave fans is ensured by generating a speed command Ncmd for the master fan drive motor in relation to position feedback from the slave fan(s) so that the speed of the master fan is increased in relation to the ability of the slave fan(s) to follow in step with the master fan.
38 Citations
14 Claims
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1. A motor vehicle cooling fan drive apparatus comprising:
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first and second juxtaposed and magnetically coupled rotary cooling fans; drive means including an electric motor connected to rotatably drive said first cooling fan, and motor controller means connected to said electric motor for controlling its running speed in accordance with the value of a speed command signal applied thereto; and system control means including means for (1) generating a desired speed value for said fans in accordance with the vehicle cooling demand, (2) determining a phase error EP according to the relative rotary positions of said first and second fans, (3) adjusting said desired speed value in a direction to reduce said phase error EP at least when said phase error is greater than a threshold error, and (4) applying a speed command signal to said motor controller means in accordance with the adjusted speed value, thereby to control said electric motor for synchronously accelerating and running said first and second fans at said desired speed value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A motor vehicle cooling fan drive apparatus comprising:
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a master cooling fan connected to be rotatably driven by an electric motor; motor controller means connected to said electric motor for controlling its running speed in accordance with the value of a speed command signal applied thereto; first and second slave fans juxtaposed and magnetically coupled to said master cooling fan; and system control means including means for (1) generating a desired speed value for said fans in accordance with the vehicle cooling demand, (2) determining a phase error EP according to the relative rotary positions of said master fan and said first slave fan, (3) adjusting said desired speed value in a direction to reduce said phase error EP at least when said phase error is greater than a threshold error, and (4) applying a speed command signal to said motor controller means in accordance with the adjusted speed value, thereby to control said electric motor for synchronously accelerating and running said master and first slave fans at said desired speed value. - View Dependent Claims (9, 10, 11, 12)
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13. A motor vehicle cooling fan drive apparatus comprising:
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a master cooling fan connected to be rotatably driven by an electric motor; motor controller means connected to said electric motor for controlling its running speed in accordance with the value of a speed command signal applied thereto; first and second slave fans magnetically coupled to said master cooling fan, but separately rotatable with respect thereto; and system control means including means for (1) generating a desired speed value for said fans in accordance with the vehicle cooling demand, (2) determining a phase error EP according to the relative rotary positions of said master fan and one of said first and second slave fans designated as a primary slave fan, (3) adjusting said desired speed value in a direction to reduce said phase error EP at least when said phase error is greater than a threshold error, and (4) applying a speed command signal to said motor controller means in accordance with the adjusted speed value, thereby to control said electric motor for synchronously accelerating and running said master and primary slave fans at said desired speed value. - View Dependent Claims (14)
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Specification