초록

A fan control system uses a closed loop system to adjust the actual operating speed of a fan or fans to a desired operating speed. The desired speed and actual speed are compared in a high gain amplifier to generate a control signal to adjust the actual operating speed of the fan given the feedback.

대표청구항 ▼

1. A fan control system, comprising:a fan having a tachometer output signal indicative of actual fan speed;a fan power controller to generate a power signal to control a speed of the fan; anda feedback control module to adjust the speed of the fan to a desired speed given the actual fan speedswherei

1. A fan control system, comprising:a fan having a tachometer output signal indicative of actual fan speed;a fan power controller to generate a power signal to control a speed of the fan; anda feedback control module to adjust the speed of the fan to a desired speed given the actual fan speedswherein the feedback control module comprises;a frequency to voltage converter to receive the tachometer output from the fan and to generate a signal representative of an actual fan speed;a speed error amplifier to receive the signal representative of actual fan speed and a speed control signal representative of a desired fan speed, and to generate a voltage control signal; andan output voltage error amplifier to receive the voltage control signal and a feedback signal from the fan power controller, the output voltage error amplifier generating a control signal to the fan power controller. 2. The fan control system of claim 1, and further comprising:a speed control module to generate the speed control signal, the speed control module comprising:a temperature block;a barometric block; anda summing amplifier to generate the speed control signal based on observed temperature and barometric conditions. 3. The fan control system of claim 1, and further comprising a speed error control module. 4. The fan control system of claim 3, wherein the speed error control module comprises:an alarm amplifier connected to receive a speed error signal from the speed error amplifier; anda speed alarm connected to the alarm amplifier to generate a speed alarm when the fan speed reaches a predetermined threshold speed. 5. The fan control system of claim 1, wherein the fan power controller is a pulse width modulator. 6. A closed loop fan control system, comprising:a fan;a fan power controller connected to provide a power signal to the fan; anda feedback control module to adjust an operating speed of the fan to match a desired fan speed, the feedback control module comprising:a frequency to voltage converter to receive a tachometer output from the fan and to generate a signal representative of an actual fan speed;a speed error amplifier to receive the signal representative of actual fan speed and a speed control signal representative of a desired fan speed, and to generate a voltage control signal; andan output voltage error amplifier to receive the voltage control signal and a feedback signal from the fan power controller, the output voltage error amplifier generating a new control signal to the fan power controller. 7. The fan control system of claim 6, and further comprising:a speed control module to generate the speed control signal, the speed control module comprising:a temperature block;a barometric block; anda summing amplifier to generate the speed control signal based on observed temperature and barometric conditions. 8. The fan control system of claim 7, and further comprising a speed error control module. 9. The fan control system of claim 8, wherein the speed error control module comprises:an alarm amplifier connected to receive a speed error signal from the speed error amplifier; anda speed alarm connected to the alarm amplifier to generate a speed alarm when the fan speed reaches a predetermined threshold speed. 10. An air-cooling system comprising:an electric fan;a control module coupled to adjust an operating speed of the electric fan based on a desired fan operating speed and an actual fan operating speed; anda feedback loop to provide a signal representative of actual fan operating speed and a fan power control signal to the control module;wherein the control module comprises:a fan power controller connected to provide the fan power control signal;a frequency to voltage converter to receive a tachometer output from the fan and to generate a signal representative of the actual fan operating speed;a speed error amplifier to receive the signal representative of the actual fan operating speed and a speed control signal representative of a desired fan operating speed, and to generate a voltage control signal; andan output voltage error amplifier to receive the voltage control signal and a feedback signal from the fan power controller, the output voltage error amplifier generating an operating speed signal control signal to the fan power controller. 11. The fan control system of claim 10, and further comprising:a speed control module to generate the speed control signal, the speed control module comprising:a temperature block;a barometric block; anda summing amplifier to generate the speed control signal based on observed temperature and barometric conditions. 12. The fan control system of claim 10, and further comprising a speed error control module. 13. The fan control system of claim 12, wherein the speed error control module comprises:an alarm amplifier connected to receive a speed error signal from the speed error amplifier; anda speed alarm connected to the alarm amplifier to generate a speed alarm when the fan speed reaches a predetermined threshold speed. 14. An air-cooling system including an electric fan, comprisinga control module coupled to adjust an operating speed of the electric fan based on a desired operating speed and an actual operating speed; wherein the control module comprises:a fan power controller connected to provide the fan power control signal;a frequency to voltage converter to receive a tachometer output from the fan and to generate a signal representative of the actual fan operating speed;a speed error amplifier to receive the signal representative of the actual fan operating speed and a speed control signal representative of a desired fan operating speed, and to generate a voltage control signal; andan output voltage error amplifier to receive the voltage control signal and a feedback signal from the fan power controller, the output voltage error amplifier generating an operating speed signal control signal to the fan power controller. 15. The fan control system of claim 14, and further comprising:a speed control module to generate the speed control signal, the speed control module comprising:a temperature block;a barometric block; anda summing amplifier to generate the speed control signal based on observed temperature and barometric conditions. 16. The fan control system of claim 14, and further comprising a speed error control module. 17. The fan control system of claim 16, wherein the speed error control module comprises:an alarm amplifier connected to receive a speed error signal from the speed error amplifier; anda speed alarm connected to the alarm amplifier to generate a speed alarm when the fan speed reaches a predetermined threshold speed. 18. fan control system, comprising:an electric fan;a fan power controller connected to provide a fan power control signal;a control module coupled to adjust an operating speed of the electric fan based on a desired fan operating speed and an actual fan operating speed comprising:a frequency to voltage converter to receive a tachometer output from the electric fan and to generate a signal representative of the actual fan operating speed;a speed error amplifier to receive the signal representative of actual fan speed an a speed control signal representative of the desired fan operating speed and to generate a voltage control signal; andan output voltage error amplifier to receive the voltage control signal and a feedback signal from the fan power controller, the output voltage error amplifier generating a new control signal to the fan power controller;a feedback loop to provide a signal representative of actual fan operating speed and fan power control signal to the control module; anda speed error control module to generate an alarm when the actual fan operating speed reaches a predetermined threshold speed. 19. A method for controlling a fan operating speed, comprising:receiving a tachometer output signal from the fan and generating a signal representative of an actual fan operating speed at a f requency to voltage converter;generating a speed control signal indicative of a desired fan operating speed;feeding back the actual fan operating speed and the speed control signal indicative of the desired fan operating speed to a speed error amplifier;generating a voltage control signal to adjust the known fan operating speed to the desired fan operating speed at the speed error amplifier; andadjusting the actual fan operating speed with a fan power controller receiving the voltage control signal using a feedback control module. 20. The method of claim 19, wherein generating a speed control signal comprises:adjusting a base speed control signal according to known temperature and barometric compensation factors. 21. The method of claim 19, wherein feeding back a known fan operating speed comprises:feeding the tachometer output signal from the fan to the frequency to voltage converter; andconverting the tachometer output signal to a voltage signal representative of the known fan operating speed. 22. The method of claim 19, wherein generating a voltage control signal comprises:comparing the speed control signal to the known fan operating speed signal in the speed error amplifier. 23. The method of claim 19, wherein adjusting the actual fan operating speed comprises:feeding back a fan power control signal to an output voltage error amplifier;applying the voltage control signal to the output voltage error amplifier; andgenerating a fan power control signal to control the fan power controller. 24. The method of claim 19, and further comprising:generating an alarm when the known fan operating speed drops below a predetermined threshold. 25. A method for controlling the operation of a fan, comprising:generating a speed control signal indicative of a desired fan speed at a frequency to voltage converter;applying the speed control signal and a feedback actual fan speed signal to a speed error amplifier;comparing the speed control signal and the actual fan speed signal in the speed error amplifier;generating a voltage control signal indicative of a desired adjustment to actual fan operating speed at the speed error amplifier;receiving the voltage control from an output voltage error amplifier and a feedback signal from a fan power controller, the output voltage error amplifier generating a new control signal to the fan power controller; andadjusting the actual fan operating speed to the desired fan speed using a feedback control module. 26. The method of claim 25, and further comprising:generating an alarm when the known fan operating speed drops below a predetermined threshold.