Solid-state magnet control

• US 7,495,879 B2
• Filed: 02/04/2005
• Issued: 02/24/2009
• Est. Priority Date: 02/04/2005
• Status: Active Grant

• Current Assignee: Hubbell Industrial Controls, Inc. (Hubbell, Inc.)
• Original Assignee: Cableform, Inc. (Hubbell, Inc.)
• Inventors: Christenson, Eric S., Thexton, Andrew S.
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): CLARK, CHRISTOPHER JAY
• Application Number:
  US11/049,902
• Publication Number:
  US 20060176635A1
• Time in Patent Office: 1,481 Days
• Field of Search: 335/290, 361/144
• US Class Current: 361/144
• CPC Class Codes: H01F 7/18 Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
• CPC Class Codes: H01F 7/206 Electromagnets for lifting, handling or transporting of magnetic pieces or material electromagnets for guidance of vehicles, workpieces B65G21/2009; for magnetic suspension or levitation H02N15/00
• CPC Class Codes: H02H 9/047 Free-wheeling circuits

Abstract

A solid-state magnet control includes a housing and magnet control circuitry mounted within the housing. The magnet control circuitry includes an insulated gate bipolar transistor (IGBT) bridge configuration and DUMP circuitry. The DUMP circuitry inhibits circuit damage to the magnet control circuitry and other components contained within the magnet control caused by overvoltage and/or voltage transients. The magnet control circuitry controls current passing through the magnet. The IGBT bridge configuration includes a LIFT HIGH IGBT, a LIFT LOW IGBT, a CLEAN HIGH IGBT, and a CLEAN LOW IGBT, as well as a capacitor bank. The DUMP circuitry includes a DUMP HIGH IGBT, a discharge diode, and a discharge resistor. The magnet control is configured to provide power loss ride through, ground fault detection, and discharge voltage control, and can accept increased voltage supply to reduce charge-up time of the magnet, and existing operator control inputs through a relay interface.

Claims

1. A magnet control for controlling a magnet during a current flow established by applying a constant voltage, said magnet control comprising:

a housing;

magnet control circuitry mounted within the housing, the magnet control circuitry including an insulated gate bipolar transistor (IGBT) bridge configuration, wherein said IGBT bridge configuration comprises a LIFT HIGH IGBT, a LIFT LOW IGBT, a CLEAN HIGH IGBT, and a CLEAN LOW IGBT, wherein the magnet control circuitry controls current passing through the magnet; and

DUMP circuitry interconnected with the magnet control circuitry, said DUMP circuitry comprises at least a DUMP HIGH IGBT, a discharge diode, and a discharge resistor thereby providing a discharge voltage control circuit,

wherein the combination of said magnet control circuitry and said DUMP circuitry act to clamp the magnet voltage to a substantially constant value thereby resulting in the magnet current declining at a substantially linear rate whereby a discharge voltage control circuit is achieved.

2. The magnet control according to claim 1, wherein said magnet control circuitry further comprises a capacitor bank.

3. The magnet control according to claim 1, wherein said magnet control is configured to provide power loss ride through.

4. The magnet control according to claim 1, wherein said magnet control is configured to accept increased voltage supply to reduce charge-up time of the magnet.

5. The magnet control according to claim 1, wherein said magnet control is configured to accept existing operator control inputs through a relay interface.

6. The magnet control according to claim 1, wherein said magnet control utilizes categories of LIFT, CLEAN, and voltage parameters.

7. The magnet control according to claim 6, wherein said LIFT parameters include FULL LIFT current, FULL LIFT pulse width modulation (PWM), FULL LIFT timeout, HOLDING current, HOLDING PWM, DRIBBLE current, PEAK current.

8. The magnet control according to claim 6, wherein said CLEAN parameters include CLEAN current, CLEAN pulse width modulation (PWM), CLEAN timeout, DRIBBLE current, DRIBBLE PWM, and DRIBBLE timeout.

9. The magnet control according to claim 6, wherein said VOLTAGE parameters include SHUTDOWN voltage, DUMP voltage, MINIMUM CAPACITOR voltage, CHARGE-UP DELTA voltage, and DUMP TEST data.

10. The magnet control according to claim 1, in combination with a data terminal configured to determine status of a variety of parameters of the magnet control.

11. The magnet control according to claim 1, wherein said magnet control is configured to detect shorted cables.

12. The magnet control according to claim 1, wherein said magnet control is configured to control multiple magnets on a beam.

13. The magnet control according to claim 1, further comprising a battery backup to enable load to be maintained by the magnet upon loss of input voltage.

14. The magnet control according to claim 1, wherein said magnet control is configured to provide ground fault detection.