Variable Speed High Efficiency Gas Compressor System

Abstract

A system for powering a compressor. The system may include a power generation unit adapted to generate AC power. An electric motor may be coupled to the power generation unit and adapted to turn at a rate proportionate to a frequency of the AC power. A compressor may be coupled to the electric motor, and an output pressure of the compressor may be directly dependent on the rate that the electric motor turns. A control system may be coupled to the power generation unit and to the compressor, and the control system may be adapted to vary the frequency of the AC power generated by the power generation unit, thereby varying the output pressure of the compressor.

1 . A system for powering a compressor, comprising:
 a power generation unit adapted to generate AC power;   an electric motor coupled to the power generation unit, the electric motor adapted to turn at a rate proportionate to a frequency of the generated AC power;   a compressor coupled to the electric motor, an output pressure of the compressor being directly dependent on the rate that the electric motor turns; and   a control system coupled to the power generation unit and to the compressor, the control system being adapted to vary the frequency of the AC power generated by the power generation unit, thereby varying the output pressure of the compressor.   
     
     
         2 . The system of  claim 1 , wherein the power generation unit further comprises:
 an engine adapted to run at variable speeds; and   an electric generator coupled to the engine and adapted to generate the AC power, the frequency of the AC power being directly dependent on the speed of the engine.   
     
     
         3 . The system of  claim 1 , wherein the power generation unit comprises a plurality of power generation units, and wherein the control system is adapted to regulate each power generation unit independently to match a power demand of the electric motor. 
     
     
         4 . The system of  claim 1 , further comprising a busbar, wherein the power generation unit and the electric motor are each coupled to the busbar such that the busbar conducts the AC power from the power generation unit to the electric motor. 
     
     
         5 . The system of  claim 4 , further comprising:
 a variable frequency drive coupled to the busbar; and   an electrical grid coupled to the variable frequency drive.   
     
     
         6 . The system of  claim 5 , wherein at least a portion of the AC power is exported from the busbar to the electrical grid, and wherein the variable frequency drive is adapted to convert the frequency of the exported AC power to standard frequency AC power. 
     
     
         7 . The system of  claim 5 , wherein standard frequency AC power is imported from the electrical grid, and wherein the variable frequency drive is adapted to convert the standard frequency AC power to the frequency of the AC power required by the electric motor. 
     
     
         8 . The system of  claim 4 , further comprising:
 a variable frequency drive coupled to the busbar; and   an auxiliary load coupled to the variable frequency drive.   
     
     
         9 . The system of  claim 8 , wherein the AC power generated by the power generation unit is supplied to the auxiliary load, and wherein the variable frequency drive is adapted to convert the frequency of the AC power generated by the power generation unit to standard frequency AC power. 
     
     
         10 . The system of  claim 4 , further comprising:
 a turbine coupled to the power generation unit, the turbine adapted to receive steam produced from waste heat from the power generation unit; and   an electric generator coupled to the turbine and to the busbar, the electric generator being driven by the turbine and generating additional AC power that is supplied to the busbar.   
     
     
         11 . A method for powering a compressor, comprising:
 varying a speed of an engine with a control system coupled to the engine;   varying a frequency of AC power generated by an electric generator coupled to the engine, the frequency of the AC power being directly dependent on the speed of the engine;   varying a speed of an electric motor coupled to the electric generator, the speed of the electric motor being directly dependent on the frequency of the AC power generated by the electric generator;   varying a speed of a compressor coupled to the electric motor, the speed of the compressor being directly dependent on the speed of the electric motor; and   varying an output pressure of the compressor, the output pressure of the compressor being directly dependent on the speed of the compressor.   
     
     
         12 . The method of  claim 11 , further comprising:
 sensing the output pressure of the compressor with the control system; and   sending a signal from the control system to the engine directing the engine to vary the speed of the engine in response to the output pressure.   
     
     
         13 . The method of  claim 11 , wherein the engine comprises a first engine and a second engine, and wherein the electric generator comprises a first electric generator and a second electric generator, the first electric generator being coupled to the first engine and the second electric generator being coupled to the second engine. 
     
     
         14 . The method of  claim 13 , further comprising regulating the first and second engines independently to efficiently match a power demand of the electric motor. 
     
     
         15 . The method of  claim 11 , further comprising supplying the AC power generated by the electric generator to the electric motor through a busbar. 
     
     
         16 . The method of  claim 15 , further comprising:
 exporting at least a portion of the AC power from the busbar to an electrical grid; and converting the frequency of the exported AC power generated by the electric generator to standard frequency AC power with a variable frequency drive.   
     
     
         17 . The method of  claim 15 , further comprising:
 importing standard frequency AC power from an electrical grid to the busbar; and converting the standard frequency AC power to the frequency of the AC power required by the electric motor.   
     
     
         18 . The method of  claim 11 , further comprising:
 producing steam with waste heat from the engine;   powering a turbine with the steam;   driving a separate electric generator with the turbine; and   generating additional AC power with the separate electric generator.   
     
     
         19 . A system for powering a compressor, comprising:
 an engine adapted to run at variable speeds;   an electric generator coupled to the engine and adapted to generate AC power, a frequency of the AC power being directly dependent on the speed of the engine;   a busbar coupled to the electric generator and adapted to receive and conduct the AC power generated by the electric generator;   an electric motor coupled to the busbar, a speed of the electric motor being directly dependent on the frequency of the AC power generated by the electric generator;   a compressor coupled to the electric motor, a speed of the compressor being directly dependent on the speed of the electric motor, the compressor producing an output pressure that is directly dependent on the speed of the compressor; and   a control system coupled to the engine and to the compressor, the control system being adapted to sense the output pressure of the compressor and to send control signals to the engine, wherein the control signals direct the engine to vary the speed of the engine until the compressor produces a predetermined output pressure.   
     
     
         20 . The system of  claim 19 , wherein the engine comprises a first engine and a second engine, the electric generator comprises a first electric generator and a second electric generator, the first engine being coupled to the first electric generator, and the second engine being coupled to the second electric generator, and wherein the control system is adapted to regulate the first and second engines independently to efficiently match a power demand of the electric motor.