Hybrid DC electromagnetic contactor

• US 7,079,363 B2
• Filed: 04/02/2003
• Issued: 07/18/2006
• Est. Priority Date: 04/12/2002
• Status: Active Grant

• Current Assignee: LG Industrial Systems Co., Ltd (LG Corporation)
• Original Assignee: LG Industrial Systems Co., Ltd (LG Corporation)
• Inventors: Chung, Yong-Ho
• Primary Examiner(s): Jackson, Stephen W.
• Assistant Examiner(s): Demakis, James A.
• Application Number:
  US10/404,061
• Publication Number:
  US 20030193770A1
• Time in Patent Office: 1,203 Days
• Field of Search: 361/13, 361/2, 361/6, 361/7, 361/8
• US Class Current: 361/13
• CPC Class Codes: H01H 2009/544 the static switching means being an insulated gate bipolar transistor, e.g. IGBT, Darlington configuration of FET and bipolar transistor
• CPC Class Codes: H01H 33/596 for interrupting dc
• CPC Class Codes: H01H 9/542 Contacts shunted by static switch means

Abstract

In a hybrid DC electromagnetic contactor, by including a power unit for supplying a certain power voltage; a main contact point of a breaking switch for providing a supply path of the power voltage by being switched in accordance with a voltage apply to an operational coil; a switch for providing a supply path of the power voltage according to a gate signal; a snubber circuit for charging voltage at the both ends of the switch in turning off of the switch and being applied-discharged an electric current when the charged voltage is not less than a certain voltage; and a discharge current removing unit for removing the discharge current by providing a discharge current path to a load block in turning off of the switch, it is possible to minimize a size of leakage current when the main contact point and the semiconductor switch are turned off, and accordingly it can be practically used.

Claims

1. A hybrid DC electromagnetic contactor, comprising:

a power unit that supplies an electrical voltage;

a main contact point of a breaking switch selectively switched to provide an electrical voltage supply path responsive to an operating voltage applied to an operational coil;

a switch operative to provide an alternative electrical voltage supply path responsive to a gate signal;

a snubber that charges a voltage applied to said switch when said switch is turned off, and being discharged by an electric current flow when the charged voltage is at least equal to a certain voltage; and

a discharge current remover that removes a discharge current by providing a discharge path to a load block when said switch is turned off.

2. The contactor of claim 1, wherein said switch comprises a first semiconductor switch.

3. The contactor of claim 1, wherein said snubber diverges from a contact point at which a cathode of a diode and a capacitor are serially contacted, a first resistance and a second resistance being serially connected to said diverged snubber, a contact point of said first and second resistances being connected to an anode of a Zener diode, said first resistance being connected to a collector of a transistor, a fourth resistance being serially connected to an emitter of said transistor.

4. The contactor of claim 1, wherein a cathode of a diode and a first end of a resistance are connected to said discharge current remover.

5. A hybrid DC electromagnetic contactor, comprising:

a power unit that supplies an electrical voltage;

a main contact point of a breaking switch selectively switched to provide an electrical voltage supply path responsive to an operating voltage applied to an operational coil;

a switch operative to provide a two-way electrical voltage supply path responsive to a gate signal, regardless of a polarity of the electrical voltage;

a snubber that maintains a certain voltage by automatically applying and discharging a current when a charged voltage applied by turning off the contactor and said switch is at least equal to the certain voltage; and

first and second discharge current removers that remove discharge current by providing a discharge current path for a charged load.

6. The contactor of claim 5, wherein said switch comprises a two-way AC switch.

7. The contactor of claim 5, wherein said switch comprises a first switching device and a second switching device.

8. The contactor of claim 7, wherein said first switching device comprises a first diode connected to a first transistor, and said second switching device comprises a second diode connected to a second transistor in the opposite direction of the first switching device.

9. The contactor of claim 7, wherein a first diode is connected in a forward direction with said first switching device, a second diode is connected in a forward direction with said second switching device, said first switching device is connected to said second switching device, and said first diode is serially connected to said second diode.

10. The contactor of claim 5, wherein a diode and a resistance are connected with each other, respectively, in said first and second discharge current removers.

17. The contactor of claim 8, wherein a cathode of said first diode is connected to an emitter of said first transistor, an anode of said first diode is connected to a collector of said first transistor, and wherein an anode of said second diode is connected to an emitter of said second transistor, while a cathode of said second diode is connected to a collector of said second transistor.

11. A hybrid DC electromagnetic contactor, comprising:

a power unit that supplies an electrical voltage;

a main contact point of a breaking switch selectively switched to provide an electrical voltage supply path responsive to an operating voltage applied to an operational coil;

a switch operative to provide a two-way electrical voltage supply path responsive to a gate signal, regardless of a polarity of the electrical voltage; and

a snubber and discharge current remover that includes a switching device that automatically performs a discharging operation to maintain a certain voltage.

12. The contactor of claim 11, wherein said switch comprises a two-way AC switch.

13. The contactor of claim 11, wherein said switch comprises a first switching device and a second switching device.

14. The contactor of claim 13, wherein said first switching device comprises a first diode connected to a first transistor in a backward-parallel arrangement, and said second switching device comprises a second diode connected to a second transistor in a backward-parallel arrangement in an opposite direction of said first switching device.

15. The contactor of claim 11, wherein said switch includes:

a first diode connected in a forward direction of said first switching device; and

a second diode connected in a forward direction of said second switching device;

wherein said first switching device is connected to said second switching device, and said first diode is serially connected to said second diode.

16. The contactor of claim 11, wherein said snubber and discharge current remover includes:

a first bridge diode connected in parallel to a capacitor;

a first resistance and a second resistance connected in parallel to said capacitor, a first end of said first resistance being connected to a contact point of a diode connected in parallel to a transistor;

a Zener diode having an anode thereof connected to a base of said transistor, a cathode of said Zener diode being connected to an other end of said first resistance;

a third resistance having a first end connected to said base of said transistor and said anode of said Zener diode, a second end of said third resistance being connected to said second resistance in series; and

a fourth resistance having a first end connected to an emitter of said transistor and a second end connected in series to a first end of a second bridge diode,

a second end of said second bridge diode being connected to a contact point of said first resistance and said capacitor.