Flow control

A pumping system for at least one aquatic application, the pumping system comprising:

• a pump;
• a motor coupled to the pump;
• and
• a controller in communication with the motor,
• the controller determining a first motor speed,
• the controller obtaining a reference flow rate,
• the controller determining a present power consumption,
• the controller determining a present flow rate, wherein a flow estimator uses curves of speed versus flow rate for discrete power consumptions to determine the present flow rate,
• the controller calculating a difference value between the reference flow rate and the present flow rate,
• the controller using at least one of integral, proportional, and 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 reaching a steady state condition.

A method of controlling a pumping system, the method comprising:

• providing a motor coupled to a pump;
• providing a controller in communication with the motor;
• determining a first motor speed value;
• determining a present power consumption value;
• obtaining a reference flow rate value;
• determining a present flow rate value using curves of speed versus flow rate for discrete power consumptions;
• generating a difference value between the reference flow rate and the present flow rate;
• and
• driving the motor at a second motor speed based on the difference value until reaching a steady state condition.