Leakage current detection and protection device for power cord

Patent metadata

Field	Value
Publication number	US-10840698-B2
Application number	US-201816212505-A
Country	US
Kind code	B2
Filing date	Dec 6, 2018
Priority date	Sep 22, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A power cord leakage current detection and protection device, including: a switch unit controlling an electrical connection between input and output ends of the device, a switch drive module, and a leakage current detection circuit which includes a leakage current detection line for detecting a leakage current on a power supply line. The switch drive module includes a semiconductor device assembly, and a solenoid assembly coupled between a power supply line and the semiconductor device assembly. The solenoid assembly includes multiple coils with their current paths coupled in parallel; the semiconductor device assembly includes multiple semiconductor devices with their current paths coupled in parallel. When at least one coil is not an open-circuit and at least one semiconductor device is not an open-circuit, the switch drive module controls the switch unit based on a leakage current signal detected by the leakage current detection circuit to disconnect the power supply.

First claim

What is claimed is:

1. A power cord leakage current detection and protection device, comprising:
a switch unit, configured to control an electrical connection between an input end and an output end of the device;
a leakage current protection unit, which includes a switch drive module and a leakage current detection circuit,
wherein the leakage current detection circuit includes a leakage current detection line, configured to detect whether a leakage current is present on a first power supply line and/or a second power supply line; and
wherein the switch drive module includes a solenoid assembly and a semiconductor assembly, the solenoid assembly being coupled between the first power supply line and the semiconductor assembly, the solenoid assembly including at least two coils with their current paths coupled in parallel, and the semiconductor assembly includes at least two semiconductor devices with their current paths coupled in parallel;
wherein when at least one of the coils is not an open-circuit and at least one of the semiconductor devices is not an open-circuit, the switch drive module controls the switch unit to disconnect the electrical connection based on a leakage current signal detected by the leakage current detection circuit.

2. The power cord leakage current detection and protection device of claim 1 , further comprising:
an open-circuit detection circuit, which includes a first detection circuit and a second detection circuit, wherein the leakage current detection line is coupled via the first detection circuit to the second power supply line, and
wherein the switch drive module is configured to control the switch unit to disconnect the electrical connection in response to the open-circuit detection circuit detecting an open-circuit in the leakage current detection line.

3. The power cord leakage current detection and protection device of claim 2 , wherein the solenoid assembly includes a first coil and a second coil with their current paths coupled in parallel, the first and second coils being wound on a same frame or on different respective frames.

4. The power cord leakage current detection and protection device of claim 3 , wherein the semiconductor assembly includes a first semiconductor device and a second semiconductor device with their current paths coupled in parallel, and either
wherein an anode of the first semiconductor device is coupled to an anode of the second semiconductor device, a control electrode of the first semiconductor device and a control electrode of the second semiconductor device are both coupled to a first end of a first capacitor, and a cathode of the first semiconductor device and a cathode of the second semiconductor device are both coupled to a second end of the first capacitor, and the first capacitor is coupled in parallel with a first drive resistor, or
wherein the open-circuit detection circuit further includes a third detection circuit, the leakage current detection line is coupled to the first power supply line via the third detection circuit, an anode of the first semiconductor device is coupled to the first detection circuit, a cathode of the first semiconductor device is coupled to a first end of a first capacitor, a control electrode of the first semiconductor device is coupled to a second end of the first capacitor, the first capacitor is coupled in parallel to a first drive resistor, an anode of the second semiconductor device is coupled to the third detection circuit, a control electrode of the second is coupled to a first end of a second capacitor, and a cathode of the second is coupled to a second end of the second capacitor, and the second capacitor is coupled in parallel to a second drive resistor.

5. The power cord leakage current detection and protection device of claim 4 , wherein the first detection circuit includes a first resistor and a first diode coupled in series, and the second detection circuit includes a second resistor and a second diode coupled in series.

6. The power cord leakage current detection and protection device of claim 5 , wherein the third detection circuit includes a third resistor and a third diode coupled in series.

7. The power cord leakage current detection and protection device of claim 2 , further comprising a signal feedback line, wherein the leakage current detection line is coupled to the first detection circuit via the signal feedback line,
wherein when the signal feedback line has an open-circuit, the switch drive module controls the switch unit to disconnect the electrical connection.

8. The power cord leakage current detection and protection device of claim 7 , further comprising a test unit which includes a test switch, wherein the test switch is coupled to the semiconductor assembly either directly or via the signal feedback line,
wherein when the test switch is closed, the switch drive module controls the switch unit to disconnect the electrical connection.

9. The power cord leakage current detection and protection device of claim 2 , further comprising a test unit which includes a test switch, wherein the test switch is coupled directly to the semiconductor assembly,
wherein when the test switch is closed, the switch drive module controls the switch unit to disconnect the electrical connection.

10. The power cord leakage current detection and protection device of claim 2 , further comprising a housing, configured to accommodate at least one of the switch unit, the leakage current protection unit and the open-circuit detection circuit.

11. The power cord leakage current detection and protection device of claim 1 , wherein the semiconductor devices include any of silicon controlled rectifiers, MOS (metal-oxide-semiconductor) transistors, and transistors.

12. An electrical appliance, comprising the power cord leakage current detection and protection device of claim 1 .

13. A power cord, comprising:
a first power supply line;
a second power supply line;
a ground line;
a leakage current detection line;
at least one signal feedback lines; and
an insulating cover,
wherein each of the at least one signal feedback lines includes a conductor line and an insulating layer covering the conductor line, wherein the insulating layer covers only the corresponding conductor line without covering any conductor line of any other signal feedback line and without covering any of the first power supply line, the second power supply line and the ground line, where the leakage current detection line covers at least the first and second power supply lines, and the insulating cover covers the leakage current detection line and the at least one signal feedback lines.

14. A power cord leakage current detection and protection device, comprising:
a switch unit, configured to control an electrical connection between an input end and an output end of the device;
a leakage current protection unit, which includes a switch drive module and a leakage current detection circuit, the switch drive module configured to control the switch unit based on a leakage current signal detected by the leakage current detection circuit, wherein the leakage current detection circuit includes:
a leakage current detection line, configured to detect whether a leakage current is present on a first power supply line and/or a second power supply line; and
a signal feedback line, configured to detect whether the leakage current detection line has an open circuit;

wherein the switch drive module includes a solenoid assembly and a semiconductor assembly, the solenoid assembly being coupled between the first power supply line and the semiconductor assembly, the solenoid

Assignees

• Li Chengli

Inventors

• Li Chengli
• Nie Shengyun

Classifications

• H01R13/713 Primary

  the switch being a safety switch · CPC title

• H01R2103/00

  Two poles · CPC title

• H01R24/30

  with additional earth or shield contacts · CPC title

• H02H1/00

  Details of emergency protective circuit arrangements · CPC title

• H02H7/228 Primary

  for covered wires or cables · CPC title