Device for pumping fluid

A method of pumping a fluid using a gear pump, wherein the method comprises steps of:

• driving a motor to rotate a drive shaft, and arranging for the drive shaft to rotate one or more rotatable components of a pump module for pumping the fluid, and for rotating a sensor target associated with the drive shaft and/or the one or more rotatable components of the pump module;
• using a sensor to sense rotation of sensor target and to generate an output signal corresponding to a rotational position of the sensor target;
• calculating the rotational position or a rotation rate of the drive shaft and/or the one or more rotatable components of the pump module based upon the output signal;
• and
• controlling the motor based upon the calculated rotational position or rotation rate to controllably pump a volume of the fluid, wherein the controlling uses at least one PID algorithm to control the motor, and wherein the method includes configuring the controller to use nested feedback loops to adjust an electrical current or an electrical excitation voltage supplied to the motor to ensure that a controlled volume of the fluid is pumped.

A device for pumping a fluid, wherein the device comprises:

• a motor for driving a rotatable drive shaft;
• a pump module to be driven in operation by the drive shaft;
• at least one sensor target operatively associated with at least one of:
• the drive shaft, one or more rotatable pumping components of the pump module, or the fluid that is pumped;
• at least one sensor for sensing a change in property of the at least one sensor target (40) as the drive shaft rotates in operation, and for generating an output signal corresponding to a rotational position of at least one of:
• the drive shaft, or the one or more rotatable pumping components of the pump module;
• and
• a controller that is operable to calculate the rotational position or a rotation rate of at least one of:
• the drive shaft, or the one or more rotatable pumping components of the pump module, based upon the output signal and to control the motor based upon the calculated rotational position or rotation rate to ensure that a controlled volume of the fluid is pumped, wherein the controller is configured to use at least one PID algorithm to control the motor, and wherein the controller is configured to use nested feedback loops to adjust an electrical current or an electrical excitation voltage applied to the motor to ensure that a controlled volume of the fluid is pumped.