Hydraulic fluid pressure control

Abstract

A hydraulic fluid pressure control system comprising: a hydraulic pump motor having an electrical input configured to receive an AC input signal and a hydraulic fluid output configured to output a pressure proportional to the frequency of the AC input signal; and electronic control circuitry connected to the electrical input, wherein: the electronic control circuitry provides an AC input signal of variable frequency. The electronic control circuitry may comprise an inverter.

What we claim is: 
     
         1 . A hydraulic fluid pressure control system comprising:
 a hydraulic pump motor having an electrical input configured to receive an AC input signal and a hydraulic fluid output configured to output a pressure proportional to the frequency of the AC input signal; and   electronic control circuitry connected to the electrical input wherein the electronic control circuitry provides an AC input signal of variable frequency.   
     
     
         2 . The hydraulic fluid pressure control system according to  claim 1 , further comprising a pressure sensor connected to the hydraulic fluid output. 
     
     
         3 . The hydraulic fluid pressure control system according to  claim 2 , wherein the pressure sensor produces an electrical output responsive to the sensed pressure of the hydraulic fluid output. 
     
     
         4 . The hydraulic fluid pressure control system according to  claim 3 , wherein the electronic control circuitry provides an AC input signal based on the electrical output. 
     
     
         5 . The hydraulic fluid pressure control system according to  claim 1 , wherein the electronic control circuitry comprises an electronic inverter. 
     
     
         6 . The hydraulic fluid pressure control system according to  claim 1 , wherein the electronic control circuitry provides an AC input signal corresponding to a target pressure of the hydraulic fluid output. 
     
     
         7 . The hydraulic fluid pressure control system according to  claim 1 , wherein the electronic control circuitry limits the rate of change of the AC input signal frequency. 
     
     
         8 . The hydraulic fluid pressure control system according to  claim 1 , wherein the pump motor acts as a power source for a directional control valve. 
     
     
         9 . The hydraulic fluid pressure control system according to  claim 1 , wherein the hydraulic pump motor acts as a hydraulic power source for well control in an underwater hydrocarbon extraction facility. 
     
     
         10 . A hydraulic fluid pressure control system comprising:
 a hydraulic pump motor having an electrical input configured to receive an AC input signal and a hydraulic fluid output configured to output a pressure proportional to the frequency of the AC input signal; and   electronic control circuitry connected to the electrical input, wherein   the electronic control circuitry provides an AC input signal of variable frequency;   a pressure sensor is connected to the hydraulic fluid output, the pressure sensor producing an electrical output responsive to the sensed pressure of the hydraulic fluid output and the electronic control circuitry providing an AC input signal based on the electrical output;   the electronic control circuitry comprises an electronic inverter;   the pump motor acts as a power source for a directional valve for well control in an underwater hydrocarbon extraction facility; and   the electronic control circuitry provides an AC input signal corresponding to a target pressure of the hydraulic fluid output.   
     
     
         11 . The hydraulic fluid pressure control system according to  claim 10 , wherein the electronic control circuitry limits the rate of change of the AC input signal frequency. 
     
     
         12 . A method for controlling the speed of a hydraulic pump motor, the hydraulic pump motor having an electrical input configured to receive an AC input signal and a hydraulic fluid output configured to output a pressure proportional to the frequency of the AC input signal, the method comprising:
 providing an AC input signal of variable frequency to the electrical input using electronic control circuitry.   
     
     
         13 . The method according to  claim 12 , further comprising the step of providing a pressure sensor connected to the hydraulic fluid output. 
     
     
         14 . The method according to  claim 13 , further comprising the steps of sensing the pressure of the hydraulic fluid output using the pressure sensor, and producing an electrical output responsive to the sensed pressure of the hydraulic fluid output. 
     
     
         15 . The method according to  claim 14 , wherein the electronic control circuitry provides an AC input signal based on the electrical output. 
     
     
         16 . The method according to  claim 12 , wherein the electronic control circuitry comprises an electronic inverter. 
     
     
         17 . The method according to  claim 12 , wherein the electronic control circuitry provides an AC input signal corresponding to a target pressure of the hydraulic fluid output. 
     
     
         18 . The method according to  claim 12 , wherein the electronic control circuitry limits the rate of change of the AC input signal frequency. 
     
     
         19 . The method according to  claim 12 , wherein the pump motor acts as a power source for a directional control valve. 
     
     
         20 . The method according to  claim 12 , wherein the hydraulic pump motor acts as a hydraulic power source for well control in an underwater hydrocarbon extraction facility.