System and method for controlling linear pump system

Abstract

Systems and methods for operating a linear pump system involve operating a linear motor system; reciprocating a linear pump and a motor control module that issues commands and a control logic input to the linear motor system. The linear motor system is operated to reciprocate an output shaft between first and second reversal positions. The linear pump is reciprocated with the output shaft to produce a flow of material. A pump reversal command reverses direction of the output shaft. A torque command controls speed of the output shaft. The control logic input reciprocates the output shaft at speeds to produce a constant output condition of the flow of material. The motor control module adjusts the torque command to operate the output shaft at an increased speed above what is necessary for the constant output condition for a temporary time period beginning when the reversal command is issued.

1 . A linear pump system comprising:
 a linear motor system that produces a reciprocating movement of an output shaft between first and second reversal positions;   a linear material pump connected to the output shaft to produce a flow of material; and   a motor control module that:
 issues a reversal command to the linear motor system to reverse direction of the output shaft; 
 issues a torque command to the linear motor system to control speed of the output shaft; and 
 issues a control logic input to the linear motor system to reciprocate the output shaft at speeds to produce a constant output condition of the flow of material; 
 wherein the motor control module adjusts the torque command to operate the output shaft at an increased speed above what is necessary for the constant output condition for a temporary time period beginning when the reversal command is issued. 
   
     
     
         2 . The linear pump system of  claim 1  wherein the linear motor system further comprises:
 a linear hydraulic motor that includes the output shaft; 
 an electric motor that receives the torque command from the motor control module; 
 a rotary hydraulic pump driven by the electric motor that provides a flow of pressurized hydraulic fluid commensurate with speed of the electric motor to control speed of the output shaft; and 
 a hydraulic dual output reversing valve coupled to the linear hydraulic motor and that receives the flow of pressurized hydraulic fluid from the rotary hydraulic pump to hydraulically reverse direction of the output shaft in response to receiving the reversal command from the motor control module. 
 
     
     
         3 . The linear pump system of  claim 1  wherein the motor control module turns off the control logic input in response to adjusting the torque command and while operating the output shaft at speeds above what is necessary for the constant output condition. 
     
     
         4 . The linear pump system of  claim 3  wherein the linear motor system further comprises:
 a position sensor connected to the linear hydraulic motor that issues a position signal in response to the output shaft moving away from one of the reversal positions; 
 wherein the motor control module alters the adjusted torque command to reduce the increased speed of the output shaft in response to receiving the position signal. 
 
     
     
         5 . The linear pump system of  claim 3  wherein the motor control module turns on the control logic input after the temporary time period terminates. 
     
     
         6 . The linear pump system of  claim 5  wherein the temporary time period terminates when a reset condition is detected. 
     
     
         7 . The linear pump system of  claim 5  wherein the linear motor system further comprises:
 a pressure sensor for sensing pressure in the flow of material; 
 wherein the reset condition comprises a sensed pressure rise. 
 
     
     
         8 . The linear pump system of  claim 1  wherein the constant output condition comprises either constant pressure output or constant flow output. 
     
     
         9 . A method for operating a linear pump system comprising:
 operating a linear motor system to reciprocate an output shaft between first and second reversal positions;   reciprocating a linear pump with the linear motor system output shaft to produce a flow of a material;   driving the linear motor system at rates to provide a constant output condition of the flow of material;   initiating a reversal in direction of the output shaft; and   driving the linear motor system at an increased rate above what is necessary for the constant output condition for a temporary time period beginning when the reversal in direction of the output shaft is initiated.   
     
     
         10 . The method for operating a linear pump system of  claim 9  and further comprising:
 operating a linear hydraulic motor having the output shaft; 
 operating an electric motor; 
 operating a rotary hydraulic pump with the electric motor to provide a flow of pressurized hydraulic fluid to the linear hydraulic motor to control speed of the output shaft; and 
 operating a hydraulic dual output reversing valve coupled to the linear hydraulic motor and that receives the flow of pressurized hydraulic fluid to reverse direction of the output shaft. 
 
     
     
         11 . The method of operating a linear pump system of  claim 10  and further comprising:
 a motor control module that coordinates operation of the electric motor and the hydraulic dual output valve, wherein: 
 the linear motor system is driven at rates to provide the constant output condition in response to receiving a control logic input from the motor control module; 
 the reversal in direction of the output shaft is initiated in response to the hydraulic dual output valve receiving a reversal command from the motor control module; and 
 the linear motor system is driven at the increased rate in response to the electric motor receiving a torque command from the motor control module. 
 
     
     
         12 . The method of operating a linear pump system of  claim 11  and further comprising:
 turning off the control logic input when the torque command is issued while operating at the increased rate. 
 
     
     
         13 . The method of operating a linear pump system of  claim 12  and further comprising:
 detecting a position of the output shaft at a reversal position; and 
 altering the torque command to reduce the increased rate in response to detecting the reversal position. 
 
     
     
         14 . The method of operating a linear pump system of  claim 12  and further comprising:
 turning on the control logic input after the temporary time period terminates. 
 
     
     
         15 . The method of operating a linear pump system of  claim 14  and further comprising:
 sensing a pressure of the output flow material; and 
 terminating the temporary time period when a pressure rise is sensed. 
 
     
     
         16 . The method of operating a linear pump system of  claim 9  wherein the constant output condition comprises either constant pressure output or constant flow output. 
     
     
         17 . A method of operating a linear pump system comprising:
 operating a linear motor system to reciprocate an output shaft between first . and second reversal positions;   reciprocating a linear pump with the linear motor system output shaft to produce a flow of a material;   driving the linear motor system at rates to provide a constant output condition of the flow of material; and   temporarily driving the linear motor system at an increased rate above what is necessary for the constant output condition when the output shaft reverses direction.   
     
     
         18 . The method of  claim 17  wherein the step of driving the linear pump comprises:
 reversing direction of the output shaft; 
 controlling speed of the output shaft; and 
 wherein the direction and speed of the output shaft are controlled with control logic to provide the constant output condition, the control logic being suspended when the linear pump is temporarily driven at the increased rate. 
 
     
     
         19 . The method of  claim 18  and further comprising:
 detecting a position of the output shaft; and 
 reducing the increased rate when the output shaft is detected moving away from a reversal position. 
 
     
     
         20 . The method of  claim 19  and further comprising:
 sensing a pressure in the flow of material; and 
 initiating the control logic when a pressure rise is sensed.