Fan speed control system

1. A fan control system, comprising:

a fan to provide a flow of coolant to a machine;

a first sensor configured to generate a first signal indicative of an operational parameter of the machine;

a second sensor associated with the fan to generate a second signal indicative of an actual speed of the fan; and

a controller communicatively coupled to the fan, the first sensor, and the second sensor, the controller being configured to:

generate a third signal indicative of a desired fan speed based on the first signal;

generate a fourth signal indicative of a difference between the desired fan speed and the actual fan speed; and

drive the fan based on the third signal and the fourth signal;

wherein generating the third signal includes:

determining a maximum achievable fan speed and a minimum achievable fan speed based on a current speed of a power source associated with the machine; and

interpolating a desired fan speed between the minimum achievable fan speed and the maximum achievable fan speed based on the first signal.

2. The system of claim 1 , wherein driving the fan based on the third signal and the fourth signal includes:

generating a fifth signal by applying at least one gain to the fourth signal; and

driving the fan in response to the third signal and the fifth signal.

3. The system of claim 2 , wherein the controller is further configured to:

generate the fifth signal only if the difference between the desired fan speed and the actual fan speed falls outside a predetermined range; and

set the fifth signal to zero if the actual fan speed falls below a predetermined threshold.

4. The system of claim 2 , wherein driving the fan in response to the third signal and the fifth signal includes:

modulating the third signal;

combining the modulated third signal and the fifth signal; and

driving the fan based on the combination.

5. The system of claim 2 , wherein the at least one gain includes at least one of a proportional gain, an integral gain, and a derivative gain.

6. The system of claim 1 , further including a pump and motor coupled to drive to the fan, wherein driving the fan includes regulating a displacement of at least one of the pump and motor based on the third signal and the fourth signal.

7. A method of controlling the speed of a fan, comprising:

receiving a first signal indicative of an operational parameter of a machine;

receiving a second signal indicative of an actual speed of the fan;

generating a third signal indicative of a desired fan speed based on the first signal;

generating a fourth signal indicative of a difference between the desired fan speed and the actual fan speed; and

driving the fan based on the third signal and the fourth signal;

wherein generating the third signal includes:

determining a maximum achievable fan speed and a minimum achievable fan speed based on a current speed of a power source associated with the machine; and

interpolating a desired fan speed between the minimum achievable fan speed and the maximum achievable fan speed based on the first signal.

8. The method of claim 7 , further including:

generating a fifth signal by applying at least one gain to the fourth signal; and

driving the fan in response to the third signal and the fifth signal.

9. The method of claim 8 , further including:

generating the fifth signal only if the difference between the desired fan speed and the actual fan speed falls outside a predetermined range; and

setting the fifth signal to zero if the actual fan speed falls below a predetermined threshold.

10. The method of claim 8 , wherein driving the fan in response to the third signal and the fifth signal includes:

modulating the third signal;

combining the modulated third signal and the fifth signal; and

driving the fan based on the combination.

11. The method of claim 8 , wherein the at least one gain includes at least one of a proportional gain, an integral gain, and a derivative gain.

12. The method of claim 7 , wherein driving the fan further includes responsively adjusting a displacement of at least one of a pump and motor coupled to drive the fan based on the third signal and the fourth signal.

13. A machine, comprising:

a power source configured to power operations of the machine;

a fan to provide a flow of coolant to the power source;

a driving element operatively coupled to the power source to drive the fan;

a first sensor configured to generate a first signal indicative of an operational parameter of the power source;

a second sensor associated with the fan to generate a second signal indicative of an actual speed of the fan; and

a controller communicatively coupled to the fan, the first sensor, and the second sensor, the controller being configured to:

generate a third signal indicative of a desired fan speed based on the first signal;

generate a fourth signal indicative of a difference between the desired fan speed and the actual fan speed; and

drive the fan based on the third signal and the fourth signal;

wherein generating the third signal includes:

determining a maximum achievable fan speed and a minimum achievable fan speed based on a current speed of a power source associated with the machine; and

interpolating a desired fan speed between the minimum achievable fan speed and the maximum achievable fan speed based on the first signal.

14. The machine of claim 13 , wherein driving the fan based on the third signal and the fourth signal includes:

generating a fifth signal by applying at least one gain to the fourth signal; and

driving the fan in response to the third signal and the fifth signal.

15. The machine of claim 14 , wherein the controller is further configured to:

generate the fifth signal only if the difference between the desired fan speed and the actual fan speed falls outside a predetermined range; and

set the fifth signal to zero if the actual fan speed falls below a predetermined threshold.

16. The machine of claim 14 , wherein driving the fan in response to the third signal and the fifth signal includes:

modulating the third signal;

combining the modulated third signal and the fifth signal; and

driving the fan based on the combination.

17. The machine of claim 13 , further including a pump and motor coupled to drive the fan, wherein driving the fan includes regulating a displacement of at least one of the pump and motor in response to the third signal and the fourth signal.