Patent ID: 7845913

Claim:
A pumping system for at least one aquatic application, the pumping system comprising: a pump; a motor coupled to the pump, a controller in communication with the motor, wherein the controller continuously performs a control sequence including: the controller determining a first motor speed, the controller obtaining a reference flow rate, the controller using a reference estimator to determine a reference power consumption of the motor using the first motor speed, the reference flow rate and predetermined pump curves of power consumption versus motor speed at discrete flow rates included in the reference estimator, the controller determining a present power consumption of the motor, the controller calculating a difference value between the reference power consumption and the present power consumption, the controller using at least one of integral, proportional, proportional-integral, proportional-derivative, and proportional-integral-derivative control to generate a second motor speed based on the difference value, and the controller attempting to drive the motor at the second motor speed until a steady state is reached.