Compensation circuit for electrical generators

• US 4,885,526 A
• Filed: 03/23/1988
• Issued: 12/05/1989
• Est. Priority Date: 03/18/1988
• Status: Expired due to Fees

• Current Assignee: Electro ERG Limited
• Original Assignee: Electro ERG Limited
• Inventors: Szabo, Leslie I.
• Primary Examiner(s): Hickey, Robert J.
• Application Number:
  US07/172,274
• Time in Patent Office: 622 Days
• Field of Search: 310/168, 310/183, 310/156, 310/201, 322/46, 322/66, 322/100
• US Class Current: 322/66
• CPC Class Codes: H02P 9/40 by variation of reluctance of magnetic circuit of generator

Abstract

A compensation circuit for electrical generators is disclosed. In an electrical generator, the electrical current generated in the armature coil induces a magnetic flux in the flux path of the generator. The compensating circuit of the invention includes a conductor that surrounds a portion of the flux path of the generator. This conductor known as the compensating coil, is supplied with a compensating circuit which has a reactive component. The compensating current induces a secondary magnetic flux that has a component that opposes the flux induced by the armature current. In a further embodiment of the invention, a twin generator--generator or twin generator--motor is employed. The compensating coil surrounds the flux path of one of the generators and the other generator or motor is used to supply compensating current to the compensating coil.

Claims

1. An alternating-current, electricity generator comprising:

a magnetic flux path;

a first conductor surrounding a portin of the magnetic flux path for generating electric current in the first conductor when magnetic flux varies in the magnetic flux path, wherein the generated current in the first conductor induces a magnetic flux in the magnetic flux path;

a second conductor surrounding a portion of the magnetic flux path for inducing, when an electric current flows in the second conductor, a compensating magnetic flux which opposes the magnetic flux induced by the generated current in the first conductor;

means for supplying to the second conductor a compensating current for inducing the compensating magnetic flux, the compensating current having a reactive component;

wherein the means for supplying the compensating current is a second alternating-current, electricity generator having;

a second magnetic flux path; and

a third conductor surrounding a portion of the second magnetic flux path for generating electric current in the third conductor when magnetic flux varies in the second magnetic flux path; and

wherein the third conductor is electrically connected to the second conductor so that electric current generated in the third conductor is supplied to the second conductor.

2. A generator as defined in claim 1 wherein the first conductor does not cut through the magentic flux path, and the second conductor does not cut through the magnetic flux path.

3. In an aternating-current, electricity generator having a magnetic flux path and a first conductor surrounding a portion of the magnetic flux path for generating circuit current having ohmic component in the first conductor when magnetic flux varies in the magnetic flux path, wherein the generated current inthe first conductor induces a magnetic flux in the magnetic flux path, a compensation circuit comprising:

a second conductor surrounding a portion of the magnetic flux path for inducing, when an electric current flows in the second conductor, a compensating magnetic flux which opposes the magnetic flux induced by the generated current in the first conductor; and

means for supplying to the second conductor a compensating current for inducing the compensating magnetic flux, the compensating current having a reactive component;

wherein the generated current in the first conductor is referred to as Ia;

wherein the voltage across the first conductor associated with the current Ia is referred toas Va;

wherein the compensating current in the second conductor is referred to as Ic;

wherein a voltage across the second conductor associated with the current Ic is referred to as Vc; and

AV is an angle in electrical measure from the voltage Va to the voltage Vc;

AA is an angle in electrical measure from the voltage Va to the current Ia; and

AC is an angle in electrical measuring from the voltage Vc to the current Ic;

wherein the following relationships are satisfied;

##EQU2##

4. A compensation circuit as defined in claim 3 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

15. A compensation circuit as defined in claim 3 wherein the magnetic flux path passes through a rotor;

and wherein a real component of electric power to the second conductor is less than a reduction in input power requirement to the rotor;

wherein

(a) a distorted input power requirement is required to rotate the rotor when a prescribed current flows in the first conductor and no current flows in the second conductor;

(b) a compensated input power requirement is required to rotate the rotor when the prescribed current flows in the first conductor and compensating current flows in the second conductor; and

(c) the reduction in input power requirement is the difference between the distorted input power requirement and the compensated input power requirements.

16. A compensation circuit as defined in claim 15 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

17. A compensation circuit as defined in claim 3 wherein the induced magnetic flux in the magnetic path that is induced by the current in the first conductor when no current flows in the second conductor causes an increased real power input requirement to the generator;

wherein the means for supplying the compensating current includes means for supplying to the second conductor compensating current for decreasing the real power input requirement to the generator and for supplying to the second conductor electric power having a real component less than a decrease in the real power input requirement to the generator.

18. A compensation circuit as defined in claim 17 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

5. In an alternating-current, electricity generator having a magnetic flux path and a first conductor surrounding a portion of the magnetic flux path for generating electric current having ohmic component in the first conductor when magnetic flux varies in the magnetic flux path, wherein the generated current in the first conductor induces a magnetic flux in the magnetic flux path, a compensation circuit comprising:

a second conductor surrounding a portion of the magnetic flux path for inducing, when an electric current flows in the second conductor, a compensating magnetic flux which opposes the magnetic flux induced by the generated current in the first conductor; and

means for supplying to the second conductor a compensating current for inducing the compensating magnetic flux, the compensating current having a reactive component, wherein the generator is a three-phase synchronous generator, and a first phase thereof is the first conductor and a second phase therof is the second conductor.

6. A compensation circuit as defined in claim 5 wherein a third phase of the generator is connected in series to the second phase thereof.

7. A compensation circuit as defined in claim 6 wherein the means for supplying the compensating current is three-phase, alternating current electricity generator/motor.

8. A compensation circuit as defined in claim 6 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

9. A compensation circuit as defined in claim 5 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

10. A compensation circuit as defined in claim 7 wherein the first conductor does not cut through the magnetic flux path;

and the second does not cut through the magnetic flux path.

11. In an alternating-current, electricity generator having a magnetic flux path and a first conductor surrounding a portion of the magnetic flux pathfor generating electric current having ohmic component in the first conductor when magnetic flux varies in the magnetic flux path, wherein the generated current in the first conductor induces a magnetic flux in the magnetic flux path, a compensation circuit comprising:

a second conductor surrounding a portion of the magnetic flux path for inducing, when an electric current flows in the second conductor, a compensating magnetic flux which opposes the magnetic flux induced by the generated current in the first conductor; and

means for supplying to the second conductor a compensating current for inducing the compensating magnetic flux, the compensating current having a reactive component;

wherein electric power having a reactive component and a real component is generated in the first conductor of the generator,

wherein the means for supplying the compensating current includes means for supplying to the second conductor electric power having a reactive component and a real component less than or equal to the real component of power generated in the first conductor.

12. A compensation circuit as defined in claim 11 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.

13. In an alternating-current, electricity generator having a magnetic flux path and a first conductor surrounding a portion of the magnetic flux path for generating electric current having ohmic component in the first conductor when magnetic flux varies in the magnetic flux path, wherein the generated current in the first conductor induces a magnetic flux in the magnetic flux path, a compensation circuit comprising:

a second conductor surrounding a portion of the magnetic flux path for inducing, when an electric current flows in the second conductor, a compensating magnetic flux which opposes the magnetic flux induced by the generated current in the first conductor; and

means for supplying to the second conductor a compensating current for inducing the compensating magnetic flux, the compensating current having a reactive component;

wherein the induced magnetic flux in the magnetic path that is induced by the current in the first conductor when no current flows in the second conductor causes an increased real power input requirement to the generator;

wherein the means for supplying the compensating current includes means for supplying to the second conductor compensating current for decreasing the real power input requirement to the generator and for supplying to the second conductor electric power having a real component less than a decrease in the real power input requirement to the generator.

14. A compensation circuit as defined in claim 13 wherein the first conductor does not cut through the magnetic flux path;

and the second conductor does not cut through the magnetic flux path.