Electronic pressure control of dual pump system

Abstract

Systems and methods for electronic pressure control of pumps in a dual pump system. The system may include a controller, a primary pump operated by the controller to maintain a system pressure in a flow path at a first pressure setpoint; a pressure transducer reading the system pressure and providing the system pressure to the controller; and a secondary pump operated by the controller to maintain the system pressure at a second pressure setpoint, the second pressure setpoint being less that the first pressure setpoint.

What is claimed is: 
     
         1 . A system for electronic pressure control of pumps in a dual pump system, the system comprising:
 a controller;   a primary pump operated by the controller to maintain a system pressure in a flow path at a first pressure setpoint;   a pressure transducer reading the system pressure and providing the system pressure to the controller; and   a secondary pump operated by the controller to maintain the system pressure at a second pressure setpoint, the second pressure setpoint being less that the first pressure setpoint.   
     
     
         2 . The system of  claim 1 , wherein the controller operates the secondary pump in a standby mode. 
     
     
         3 . The system of  claim 1 , further comprising a primary motor driving the primary pump. 
     
     
         4 . The system of  claim 3 , wherein the controller operates the primary pump to maintain the system pressure at the first pressure setpoint by varying a first speed of the primary motor. 
     
     
         5 . The system of  claim 4 , further comprising a secondary motor driving the secondary pump. 
     
     
         6 . The system of  claim 5 , wherein the controller operates the secondary pump to maintain the system pressure at a second pressure setpoint by varying a second speed of the secondary motor. 
     
     
         7 . The system of  claim 1 , wherein the controller comprises a proportional-integral-derivative (PID) controller including an outer loop monitoring the system pressure and an inner loop controlling at least one of a first speed of the primary pump and a second speed of the secondary pump. 
     
     
         8 . The system of  claim 1 , wherein at least one of the primary pump and the secondary pump is an electronically pressure compensated pump. 
     
     
         9 . The system of  claim 8 , wherein each of the primary pump and the secondary pump is an electronically pressure compensated pump. 
     
     
         10 . The system of  claim 1 , wherein the controller is a first controller associated with the primary pump and the system further comprises a second controller associated with the secondary pump. 
     
     
         11 . A method of electronic pressure control of pumps in a dual pump system, the method comprising:
 maintaining, by a controller operating a first pump, a system pressure in a closed fluid system at or above a first setpoint pressure by:
 receiving, from a pressure transducer, the system pressure; 
 comparing the system pressure with the first setpoint pressure; and 
 adjusting, based on comparing the system pressure with the first setpoint pressure, a first speed of the first pump; and 
   monitoring, by the controller operating a second pump, the system pressure, received from the pressure transducer, to maintain the system pressure above a second setpoint pressure, the second setpoint pressure being less than the first setpoint pressure, by:
 comparing the system pressure with the second setpoint pressure; 
 determining, based on comparing the system pressure with the second setpoint pressure, that the system pressure is below the second setpoint pressure; and 
 initiating the second pump, in response to determining the system pressure is below the second setpoint pressure. 
   
     
     
         12 . The method of  claim 11 , further comprising:
 determining, based on comparing the system pressure with the secondary setpoint pressure, that the system pressure is above a third setpoint pressure; and   placing the secondary pump in a standby mode, in response to determining that the system pressure is above a third setpoint pressure.   
     
     
         13 . The method of  claim 12 , wherein the third setpoint pressure and the secondary setpoint pressure are a same pressure. 
     
     
         14 . The method of  claim 12 , wherein the secondary setpoint pressure is less than the third setpoint pressure. 
     
     
         15 . The method of  claim 14 , wherein the third setpoint pressure is less than the primary setpoint pressure. 
     
     
         16 . The method of  claim 11 , further comprising adjusting the secondary setpoint pressure. 
     
     
         17 . The method of  claim 16 , further comprising adjusting both the first setpoint pressure and the second set point pressure such that the first set point pressure is lower than the second setpoint pressure. 
     
     
         18 . The method of  claim 11 , further comprising:
 detecting instability in the system pressure; and   reducing the secondary setpoint pressure.   
     
     
         19 . The method of  claim 11 , further comprising:
 analyzing the system pressure over one or more runs of the secondary pump;   determining the system pressure is stable over the one or more runs of the secondary pump; and   increasing the secondary setpoint pressure.   
     
     
         20 . A computer system for electronic pressure control of pumps in a dual pump system, the computer system comprising:
 at least one processor;   a memory in communication with the processor and containing instructions that when executed cause the processor to:
 maintain, by operating a primary pump, a system pressure in a closed fluid system at or above a primary setpoint pressure by: 
 receiving, from a pressure transducer, the system pressure; 
 comparing the system pressure with the primary setpoint pressure; and 
 adjusting, based on comparing the system pressure with the primary setpoint pressure, a first output of a primary pump; and 
   monitor the system pressure, received from the pressure transducer, to maintain the system pressure above a secondary setpoint pressure, the secondary setpoint pressure being less than the primary setpoint pressure, by:
 comparing the system pressure with the secondary setpoint pressure; 
 determining, based on comparing the system pressure with the secondary setpoint pressure, that the system pressure is below the secondary setpoint pressure; and 
 initiating a secondary pump, in response to determining the system pressure is below the secondary setpoint pressure.