Flow control

• US 7,845,913 B2
• Filed: 12/11/2006
• Issued: 12/07/2010
• Est. Priority Date: 08/26/2004
• Status: Active Grant

• Current Assignee: Danfoss Power Electronics A/S (Danfoss A/S), Pentair Water Pool And Spa Incorporated (Pentair Plc (Ireland))
• Original Assignee: Pentair Water Pool And Spa Incorporated (Pentair Plc (Ireland))
• Inventors: Lungeanu, Florin, Kjaer, Gert, Berthelsen, Lars Hoffmann, Westermann-Rasmussen, Peter, Stiles, Robert W. Jr.
• Primary Examiner(s): Kramer; Devon C
• Assistant Examiner(s): Weinstein; Leonard J
• Application Number:
  US11/609,101
• Publication Number:
  US 20070154320A1
• Time in Patent Office: 1,457 Days
• Field of Search: 417/42, 417/43, 417/44.1, 417/53, 417/22, 417/44.11
• US Class Current: 417/44.11
• CPC Class Codes: F04B 2203/0208 Power
• CPC Class Codes: F04B 2203/0209 Rotational speed
• CPC Class Codes: F04B 2205/05 Pressure after the pump outlet
• CPC Class Codes: F04B 2205/09 Flow through the pump
• CPC Class Codes: F04B 49/065 and making use of computers
• CPC Class Codes: F04B 49/106 Responsive to pumped volume
• CPC Class Codes: F04B 49/20 by changing the driving speed
• CPC Class Codes: F04B 49/22 by means of valves F04B49/03 takes precedence
• CPC Class Codes: F04D 13/06 the pump being electrically driven
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: F04D 15/0227 Lack of liquid level being detected using a flow transducer
• CPC Class Codes: F04D 15/0236 Lack of liquid level being detected by analysing the parameters of the electric drive, e.g. current or power consumption

Abstract

A pumping system for moving water of a swimming pool includes a water pump and a variable speed motor. The pumping system further includes means for determining a first motor speed of the motor, means for determining first and second performance values of the pumping system, and means for comparing the first and second performance values. The pumping system further includes means for determining an adjustment value based upon the comparison, means for determining a second motor speed based upon the adjustment value, and means for controlling the motor in response to the second motor speed. In one example, the pumping system includes means for determining a value indicative of a flow rate of water moved by the pump. In addition or alternatively, the pumping system includes a filter arrangement. A method of controlling the pumping system for moving the water of the swimming pool is also disclosed.

Claims

1. 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.

2. The pumping system of claim 1, wherein the first motor speed is determined from a present shaft speed of a synchronous motor.

3. The pumping system of claim 1, wherein the present power consumption is based on at least one of current and voltage provided to the motor.

4. The pumping system of claim 1, wherein the present power consumption is based on at least one of a power factor, resistance, and friction of the motor.

5. The pumping system of claim 1, wherein the difference value is limited to a predetermined range to generate an error value.

6. The pumping system of claim 5, wherein a maximum error value is about 200 watts.

7. The pumping system of claim 5, wherein the error value is multiplied by an integration constant to generate an adjustment value.

8. The pumping system of claim 7, wherein the integration constant is increased when the error value is larger in order to provide larger speed changes and decreased when the error value is smaller in order to provide smaller speed changes.

9. The pumping system of claim 7, wherein the integration constant is increased to increase an iterative process cycle time and decreased to reduce the iterative process cycle time.

10. The pumping system of claim 7, wherein the controller performs a summation calculation to add the adjustment value to a previous motor speed to generate the second motor speed.

11. The pumping system of claim 10, wherein the second motor speed is limited to a maximum value of about 3450 revolutions per minute and a minimum value of about 800 revolutions per minute.