Apparatus and method for controlling self-contained power generation and power utilization system

• US 20030178960A1
• Filed: 03/21/2002
• Published: 09/25/2003
• Est. Priority Date: 03/21/2002
• Status: Abandoned Application

• Current Assignee: Rowan Companies Incorporated
• Original Assignee: Rowan Companies Incorporated
• Inventors: Kassing, David M.
• Application Number:
  US10/103,006
• Publication Number:
  US 20030178960A1
• Time in Patent Office: Days
• US Class Current: 318/430
• CPC Class Codes: H02P 9/04 Control effected upon non-electric prime mover and dependent upon electric output value of the generator

Abstract

A system and method is disclosed for drilling a borehole using a silicon controlled rectifier (SCR) system. The SCR system includes analog rack mounted hardware cards for control of an engine AC generator and a DC load. The engine AC generator of the SCR system generates alternating current (AC) that is then converted to direct current (DC) by a silicon controlled rectifier transformer connected to the output of the engine AC generator. The DC power from the silicon controlled rectifier transformer drives one or more DC motors that are coupled to a load by a mechanical linkage. An AC generator controller controls the engine AC generator and includes an engine control module that controls operating speed of the engine AC generator and air-fuel mixture at engine start. A DC load controller coupled to the silicon controlled rectifier transformer and DC motors performs automatic load share control between the DC motors.

Claims

1. A silicon controlled rectifier (SCR) system for drilling a borehole, said SCR system including modular analog hardware comprising:

a SCR that converts alternating current (AC) to direct current (DC);

an engine AC generator for generating alternating current coupled to said SCR;

an AC generator controller coupled to the engine AC generator;

one or more DC motors coupled to the SCR;

a DC load coupled to said one or more DC motors through mechanical means;

a DC load controller coupled to the SCR and DC motors, wherein said DC load controller further comprises;

isolator hardware that receives a first signal and a second signal, said isolator hardware filtering the first signal and the second signal to reduce noise and carriers;

load share hardware coupled to the isolator hardware, wherein said load share hardware receives the filtered first signal and second signal and determines the error between the two signals;

feedback hardware coupled to the load share hardware, said feedback hardware modifying a power output of one motor based on the error; and

wherein said DC load controller performs automatic load share control between the DC motors as each DC motor powers up.

2. The SCR system of claim 1 wherein said DC load controller receives control parameters from the SCR and generates control signals to the DC motors.

3. The SCR system of claim 1 wherein said DC motors are shunt wound DC motors.

4. The SCR system of claim 1 wherein said mechanical means is a rotatable shaft.

5. The SCR system of claim 1 wherein said AC generator controller further comprises an engine control module that controls operating speed of the engine AC generator.

6. The SCR system of claim 1 wherein said AC generator controller further comprises an engine control module that controls air-fuel mixture at engine start.

7. The SCR system of claim 1 wherein said DC load is a mud pump.

8. The SCR system of claim 1 wherein said engine of the engine AC generator is a diesel engine.

9. A method for drilling a borehole utilizing a modular analog hardware silicon controlled rectifier (SCR) system, comprising the steps of:

performing an engine start of an engine AC generator using a lean mixture of air and fuel, wherein said engine AC generator is coupled to a engine control module that controls said mixture of air and fuel;

adjusting said engine AC generator using said engine control module to a constant engine speed by performing feedback control; and

drilling a borehole by maintaining constant engine speed that generates sufficient rotation of a drill bit.

10. The method of claim 9 wherein said engine of the engine AC generator is a diesel engine.

11. The method of claim 9, wherein the step of drilling a borehole further comprises the steps of:

transforming alternating current (AC) power generated by the engine AC generator into direct current (DC) power using a silicon controlled rectifier (SCR);

powering one or more DC motors using said SCR transformed DC power, wherein said DC motors operate a drilling mechanism; and

controlling the steps of transforming AC to DC power and powering the DC motors by utilizing a DC load controller coupled to the SCR and DC motors.

12. The method of claim 11, wherein said DC load controller performs automatic load share control between two or more DC motors.

13. The method of claim 12, wherein automatic load share control further comprises the steps of:

receiving a first signal and a second signal in isolator hardware, said isolator hardware filtering the first signal and the second signal to reduce noise and carriers;

determining the error between the two signals, said determining occurring in load share hardware coupled to the isolator hardware, wherein said load share hardware receives the filtered first signal and second signal; and

modifying a power output of one motor based on the error, said modifying occurring in feedback hardware coupled to the load share hardware.

14. A hardwired control system of modular design for drilling a borehole, comprising:

a silicon controlled rectifier that converts alternating current (AC) to direct current (DC);

a diesel engine AC generator for generating alternating current coupled to said SCR;

an AC generator controller coupled to the diesel engine AC generator, wherein said AC generator controller includes an engine control module that controls operating speed of the diesel engine AC generator and air-fuel mixture at diesel engine start;

one or more DC motors coupled to said silicon controlled rectifier; and

a DC load controller coupled to said silicon controlled rectifier and said DC motors, said DC load controller receiving control parameters from the silicon controlled rectifier and DC motors and generating control signals to the silicon controlled rectifier and DC motors.

15. The hardwired control system of claim 14 wherein said hardwire control system includes analog circuitry.

16. A hardwired control system of modular design for drilling a borehole, comprising:

a transformer that converts alternating current (AC) to direct current (DC);

a diesel engine AC generator for generating alternating current coupled to said transformer;

an AC generator controller coupled to the diesel engine AC generator;

a DC load coupled to said transformer, wherein said DC load is an electric motor; and

a DC load controller coupled to said transformer and DC load, said DC load controller receiving control parameters from the transformer and DC load and outputting control signals to the transformer and DC load.

17. The hardwired control system of claim 16 wherein said AC generator controller includes an engine control module that controls operating speed of the diesel engine AC generator and air-fuel mixture at diesel engine start.

18. The hardwired control system of claim 17 wherein the transformer is a silicon controlled rectifier (SCR).

19. The hardwired control system of claim 16 wherein said hardwire control system includes analog circuitry.