Booster pump controller and method of use
The disclosure provides a controller and server combination, which implements a set of software programs to control a booster pump system. In a preferred embodiment, the software derives quadratic models for the pump performance curves, and the system curve. The system monitors the flow rate of the system, the pump performance curve model and the system curve model to adjust the drive frequency and the number of active pumps to meet flow rate demand efficiency.
1. A controller for operating a pump system for a hydraulic system comprising:
a processor, including a memory;
a signal generator, operatively connected to the processor;
a set of pumps, operatively connected to the signal generator and supplying water to the hydraulic system;
a suction pressure sensor, operatively connected to the hydraulic system and the processor, generating a first pressure signal;
a discharge pressure sensor, operatively connected to the hydraulic system and the processor, generating a second pressure signal;
a set of instructions, stored in the memory, which when executed cause the pump system to implement the steps of:
deriving a quadratic system curve model;
reading the first pressure signal;
deriving a quadratic pump performance curve model;
reading the second pressure signal; and
initiating the quadratic system curve model and the quadratic pump performance curve model, using the first pressure signal and the second pressure signal, to alternatively activate and deactivate a pump, of the set of pumps, to supply the hydraulic system.
2. The controller of claim 1 , wherein the step of deriving the quadratic system curve model further comprises:
assuming that a static head and a flow rate through the hydraulic system obey a second order polynomial form.
3. The controller of claim 2 , wherein the second order polynomial form is:
h
sc
=
a
sc
Q
2
+
c
sc
where:
h sc =a head for the quadratic system curve model;
Q=a flow rate for the hydraulic system; and
a sc and c sc =a set of quadratic system curve coefficients.
4. The controller of claim 1 , wherein the step of deriving the quadratic pump performance curve model further comprises:
assuming that a head pressure and a flow rate through the set of pumps obey a second order polynomial form.
5. The controller of claim 4 , wherein the second order polynomial form is:
h
mp
=
a
mpx
Q
2
+
b
mpx
Q
+
c
mpx
where:
h mp =a head pressure for the set of pumps;
Q=a flow rate for the set of pumps; and
a mpx , b mpx , c mpx =a set of quadratic coefficients for the set of pumps.
6. The controller of claim 5 , wherein the step of deriving the quadratic pump performance curve model further comprises:
deriving the set of quadratic coefficients for a pump combination of the set of pumps.
7. The controller of claim 6 , wherein the step of deriving the set of quadratic coefficients further comprises:
deriving the set of quadratic coefficients based on an empirically derived set of pump data.
8. The controller of claim 1 , wherein the step of initiating further comprises:
determining a number of active pumps for the set of pumps;
determining a drive frequency for the set of pumps;
retrieving a first set of quadratic equation coefficients, corresponding to the number of active pumps, for the quadratic pump performance curve model;
retrieving a second set of quadratic equation coefficients for the quadratic system curve model;
solving for an operating flowrate;
solving for an operating head;
stopping an active pump, of the set of pumps, if the operating flowrate is less than a maximum flowrate for one less than the number of active pumps; and
starting an inactive pump, of the set of pumps, if the operating flowrate is greater than the maximum flowrate for the number of active pumps.
9. The controller of claim 8 , wherein the set of instructions further comprises instructions that when executed cause the controller to implement the step of:
adding a suction pressure to the quadratic pump performance curve model, based on the first pressure signal.
10. The controller of claim 8 , wherein the set of instructions further comprises instructions that when executed cause the controller to implement the step of:
modifying the quadratic pump performance curve model, based on the drive frequency.
11. The controller of claim 8 , wherein the set of instructions further comprises instructions that when executed cause the controller to implement the step of:
increasing the drive frequency, if the second pressure signal indicates a discharge pressure less than the operating head.
12. The controller of claim 8 , wherein the set of instructions further comprises instructions that when executed cause the controller to implement the step of:
decreasing the drive frequency, if the second pressure signal indicates a discharge pressure greater than the operating head plus an error factor.
13. The controller of claim 8 , wherein the set of instructions further comprises instructions that when executed cause the controller to implement the step of:
stopping a last active pump of the set of pumps, if the drive frequency is below a preset minimum drive frequency.
14. The controller of claim 8 , wherein the step of solving for the operating flowrate further comprises:
setting the quadratic pump performance curve model equal to the quadratic system curve model.
15. The controller of claim 8 , wherein the step of solving for the operating head further comprises:
applying the quadratic system curve model in a form of:
h
op
=
a
sc
Q
op
2
+
c
sc
where:
h op =an operating head pressure;
Q op =an operating flow rate; and
a sc and c sc =the second set of quadratic equation coefficients.
16. A method for operating a pump system for a hydraulic system comprising:
providing a processor, including a memory;
providing a signal generator, operatively connected to the processor;
providing a set of pumps, operatively connected to the signal generator and supplying water to the hydraulic system;
providing a suction pressure sensor, operatively connected to the hydraulic system and the processor, generating a first pressure signal;
providing a discharge pressure sensor, operatively connected to the hydraulic system and the processor, generating a second pressure signal; and
providing a set of instructions, stored in the memory, which when executed cause the pump system to implement the steps of:
deriving a quadratic system curve model;
reading the first pressure signal;
deriving a quadratic pump performance curve model;
reading the second pressure signal; and
initiating the quadratic system curve model and the quadratic pump performance curve model, using the first pressure signal and the second pressure signal, to alternatively activate and deactivate a pump, of the set of pumps, to supply the hydraulic system.
17. The method of claim 16 , wherein the step of deriving the quadratic system curve model further comprises:
assuming that a static head and a flow rate through the hydraulic system obey a second order polynomial form.
18. The method of claim 17 , wherein the second order polynomial form is:
h
sc
=
a
sc
Q
2
+
c
sc
where:
h sc =a head for the quadratic system curve model;
Q=a flow rate for the hydraulic system; and
a sc and c sc =a set of quadratic system curve coefficients.
19. The method of claim 16 , wherein the step of deriving the quadratic pump performance curve model further comprises:
assuming that a head pressure and a flow rate through the set of pumps obey a second order polynomial form.
20. The method of claim 19 , wherein the second order polynomial form is:
h
mp
=
a
mpx
Q
2
+
b
mpx
Q
+
c
mpx
where:
h mp =a head pressure for the set of pumps;
Q=a flow rate for the set of pumps; and
a mpx , b mpx , c mpx =a set of quadratic coefficients for the set of pumps.
21. The method of claim 20 , wherein the step of deriving the quadratic pump performance curve model further comprises:
deriving the set of quadratic coefficients for a pump combination of the set of pumps.
22. The method of claim 21 , wherein the step of deriving the set of quadratic coefficients further comprises:
deriving the set of quadratic coefficients based on an empirically derived set of pump data.
23. The method of claim 16 , wherein the step of initiating further comprises:
determining a number of active pumps for the set of pumps;
determining a drive frequency for the set of pumps;
retrieving a first set of quadratic equation coefficients, corresponding to the number of active pumps, for the quadratic pump performance curve model;
retrieving a second set of quadratic equation coefficients for the quadratic system curve model;
solving for an operating flowrate;
solving for an operating head;
stopping an active pump, of the set of pumps, if the operating flowrate is less than a maximum flowrate for one less than the number of active pumps; and
starting an inactive pump, of the set of pumps, if the operating flowrate is greater than the maximum flowrate for the number of active pumps.
24. The method of claim 23 , wherein the step of providing the set of instructions further comprises providing instructions that when executed cause the pump system to implement the step of:
adding a suction pressure to the quadratic pump performance curve model, based on the first pressure signal.
25. The method of claim 23 , wherein the step of providing the set of instructions further comprises providing instructions that when executed cause the pump system to implement the step of:
modifying the quadratic pump performance curve model, based on the drive frequency.
26. The method of claim 23 , wherein the set of instructions further comprises instructions that when executed cause the pump system to implement the step of:
increasing the drive frequency, if the second pressure signal indicates a discharge pressure less than the operating head.
27. The method of claim 23 , wherein the step of providing the set of instructions further comprises providing instructions that when executed cause the pump system to implement the step of:
decreasing the drive frequency, if the second pressure signal indicates a discharge pressure greater than the operating head plus an error factor.
28. The method of claim 23 , wherein the step of providing the set of instructions further comprises providing instructions that when executed cause the pump system to implement the step of:
stopping a last active pump of the set of pumps, if the drive frequency is below a preset minimum drive frequency.
29. The method of claim 23 , wherein the step of solving for the operating flowrate further comprises:
setting the quadratic pump performance curve model equal to the quadratic system curve model.
30. The method of claim 23 , wherein the step of solving for the operating head further comprises:
applying the quadratic system curve model in a form of:
h
op
=
a
sc
Q
op
2
+
c
sc
where:
h op =an operating head pressure;
Q op =an operating flow rate; and
a sc and c sc =the second set of quadratic equation coefficients.