Modular current sensor for modularized servo control system

• US 7,459,900 B2
• Filed: 02/05/2007
• Issued: 12/02/2008
• Est. Priority Date: 02/03/2006
• Status: Expired due to Fees

• Current Assignee: BAE Systems Land and Armaments LP (BAE Systems Plc)
• Original Assignee: BAE Systems Land and Armaments LP (BAE Systems Plc)
• Inventors: Shoemaker, Jeffrey W., Grupa, Timothy M., Stocker, Stephen M., Woodland, Lane L., Sukup, Martin J., Walters, Keith A., Badzinski, David J., Bartness, Bret C.
• Primary Examiner(s): Nguyen; Ha
• Assistant Examiner(s): Kusumakar; Karen M
• Application Number:
  US11/702,445
• Publication Number:
  US 20070273359A1
• Time in Patent Office: 666 Days
• Field of Search: 327/117.R, 327/117.H, 318/560, 318/580, 318/599, 318/625
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08

Abstract

A modular current sensing system for a servo control system that includes a magnetic core with an open center portion and a connection plate that includes at least three wire connectors, wherein the wire connectors are capable of connecting at least two wires electrically in series. The system also includes a plurality of wires, including a first wire with a first end and a second end, wherein the first end of the first wire is electrically connected to a first power source, and the second end of the first wire is connected to the connection plate at the first wire connector and wherein the first wire passes through the open portion defined by the magnetic core at least once. A first motor current flowing through the first wire induces a core current to flow in the magnetic core, causing the magnetic core to emit a magnetic field. A Hall effect sensor detects the magnetic field, produces an output current, and delivers the output current to a control device within a servo control system.

Claims

1. A modular current sensing system for a servo control system comprising:

a magnetic core defining an open center portion;

a connection plate including at least three wire connectors, including a first, a second, and a third wire connector, wherein each wire connector is capable of connecting at least two wires electrically in series and the first wire connector is electrically connected to a primary winding of a first motor;

a plurality of wires, including;

a first wire with a first end and a second end, wherein the first end of the first wire is electrically connected to a first power source, and the second end of the first wire is connected to the connection plate at the first wire connector and wherein the first wire passes through the open portion defined by the magnetic core at least once, the first wire thereby inducing a core current to flow in the magnetic core and causing the magnetic core to emit a magnetic field upon initiation of a first motor current flowing between the power source and the primary winding of the first motor;

a second wire with a first end connected to the second wire connector and a second end connected to the third wire connector, and wherein the second wire passes through the open portion defined by the magnetic core at least once;

a Hall effect sensor that detects the magnetic field, produces an output current, and delivers the output current to a control device within a servo control system; and

wherein the first and second connectors are adapted to receive a splicing device to electrically connect the first and second connectors and cause the first and second wires when spliced to become one effective wire that wraps around the core in multiple places to produce multiple magnetic fields.

2. The current sensing system of claim 1 wherein the second wire is electrically connected to the secondary winding of the first motor.

3. The current sensing system of claim 1 wherein at least one of the wire connectors is connected only to one of the plurality of wires.

4. The current sensing system of claim 1 further including the splicing device electrically connecting the first wire connector and the second wire connector.

5. The current sensing system of claim 1, wherein at least one of the second wire connector and the third wire connector is electrically connected to a winding of a second motor.

6. The current sensing system of claim 5, wherein the first motor and the second motor have different rms current ratings.

7. The current sensing system of claim 1, wherein the second motor is electrically connected to a second power source connected through one of the plurality of wires.

8. The current sensing system of claim 7, wherein the second power source is capable of supplying substantially more power than the first power source.

9. A method for sensing current flowing from a power source to a motor in a servo control system comprising:

generating a primary current in the power source;

conducting the primary current through a first primary wire;

winding the first primary wire about a magnetic core, inducing a first core current and a first magnetic core;

connecting and a first primary wire to a connection plate;

conducting the primary current through the connection plate, through a splice device, back through the connection plate, and into a second primary wire;

winding the second primary wire around the core, inducing a second core current in the magnetic core and a second magnetic field;

sensing the and second magnetic fields with a Hall effect sensor and generating an output current proportional to the sum of all core currents; and

sending the output current to a control device in a servo control system.

10. The current sensing method of claim 9, further comprising

generating a secondary current in the power source;

conducting the secondary current through a first secondary wire;

connecting a first end of the first secondary wire to the connection plate;

winding the first secondary wire about a magnetic core, inducing a third core current and a third magnetic field in the magnetic core;

connecting a second end of the first secondary wire to the connection plate; and

further sensing the third magnetic field with the Hall effect sensor.