Ground fault protection circuit and ground fault circuit interrupter

• US 10,033,180 B2
• Filed: 10/19/2015
• Issued: 07/24/2018
• Est. Priority Date: 11/13/2014
• Status: Active Grant

• Current Assignee: Ze Chen
• Original Assignee: Ze Chen
• Inventors: Pan, Xincheng, Chen, Ze
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Warmflash, Michael
• Application Number:
  US14/886,445
• Publication Number:
  US 20170047726A1
• Time in Patent Office: 1,009 Days
• CPC Class Codes: H02H 11/002 in case of inverted polarity or connection; with switching for obtaining correct connection
• CPC Class Codes: H02H 3/04 with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned watching of pilot wires H02H1/0084; protection of protective arrangements H02H7/008; indication of the state of electronic switches H03K17/18
• CPC Class Codes: H02H 3/33 using summation current transformers H02H3/347 takes precedence

Abstract

The present invention relates to a ground fault protection circuit and a ground fault circuit interrupter. A ground fault protection circuit may include a power supply circuit, a ground fault detection circuit, a signal amplifying and shaping circuit, a microcontroller control circuit, a power supply detection and indicator circuit, a tripping mechanism control circuit, and a reverse grounding detection and execution circuit. A ground fault circuit interrupter may comprise an interrupter body with a ground fault protection circuit in the interrupter body. The practice of the present disclosure may address installation safety risks of conventional ground fault circuit interrupters and arc fault circuit interrupter and improve the safety of ground fault circuit interrupters.

Claims

1. A ground fault protection circuit, comprising:

a power supply circuit;

a ground fault detection circuit;

a signal amplifying and shaping circuit;

a microcontroller control circuit;

a power supply detection and indicator circuit;

a tripping mechanism control circuit; and

a reverse grounding detection and execution circuit, wherein;

the microcontroller control circuit carries out power-on self-test and reset for the ground fault protection circuit;

the ground fault detection circuit comprises a leakage detection circuit and a grounding detection circuit, which detect leakage failure and grounding failure, respectively;

the signal amplifying and shaping circuit comprises a leakage detection and signal amplifying circuit and a signal shaping circuit, which are connected to each other and carry out amplifying and shaping on a leakage detection signal;

the power supply detection and indicator circuit comprises a power supply detection circuit and an indicator circuit, which are connected to each other and carry out detection and displaying of a power status;

the reverse grounding detection and execution circuit comprises a reverse connection detection control circuit and a detection and execution circuit, which are connected to each other and carry out detecting of a reverse connection of the ground fault protection circuit in a reset state and in a tripping state;

the power supply circuit comprises a power supply filter circuit, a first rectifier circuit, a first filter and regulator circuit, and a second filter and regulator circuit;

the microcontroller control circuit comprises a microcontroller, a first capacitor, and a reset filter circuit;

the tripping mechanism control circuit comprises a reset switch, which is provided on a live line and a neutral line of the ground fault protection circuit, and a control circuit that controls the reset switch;

the first filter and regulator circuit is connected to the ground fault detection circuit;

the second filter and regulator circuit is connected to the signal amplifying and shaping circuit and the microcontroller control circuit;

the ground fault detection circuit, the signal amplifying and shaping circuit, and the microcontroller control circuit are connected in sequence;

the microcontroller control circuit is connected to the power supply detection and indicator circuit and the tripping mechanism control circuit;

the power supply filter circuit is connected to an input terminal of the live line;

a first input terminal and a second input terminal of the first rectifier circuit are respectively connected to an input terminal of the neutral line and an output terminal of the power supply filter circuit;

a first pin of the first rectifier circuit is grounded;

a second pin of the first rectifier circuit is connected to both the first filter and regulator circuit and the second filter and regulator circuit;

the reset filter circuit comprises a reset IC and a second capacitor;

a first pin of the reset IC is connected to a VCC of the ground fault protection circuit, a second pin of the reset IC is connected to a reset terminal of the microcontroller, and a third pin of the reset IC is grounded;

the second capacitor is connected between the second and third pins of the reset IC;

the first capacitor is connected between a power supply terminal of the microcontroller and a ground;

the power supply terminal of the microcontroller is connected to the VCC;

a ground terminal of the microcontroller is grounded; and

the reset switch is positioned on the live line and the neutral line after the grounding detection circuit.

2. The ground fault protection circuit according to claim 1, wherein:

the power supply filter circuit comprises an inductor coil;

the first filter and regulator circuit comprises a first resistor, a third capacitor, and an internal regulator circuit of a first pin of a leakage signal processing IC

the first resistor is connected between the second pin of the first rectifier circuit and the first pin of the leakage signal processing IC;

the third capacitor is connected between the first pin of the leakage signal processing IC and the ground;

the second filter and regulator circuit comprises a second resistor, a stabilivolt, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a power supply IC, an eighth capacitor, a ninth capacitor, a tenth capacitor, and an eleventh capacitor;

the second resistor is connected between the second pin of the first rectifier circuit and to a first pin of the power supply IC;

a positive electrode of the stabilivolt is grounded;

a negative electrode of the stabilivolt is connected to the first pin of the power supply IC;

the fourth, fifth, sixth, and seventh capacitors are connected in parallel between the first pin of power supply IC and the ground;

the eighth, ninth, tenth, and eleventh capacitors are connected in parallel between a second pin of the power supply IC and the ground;

the second pin of the power supply IC is connected to the VCC;

and the third pin of the power supply IC is grounded;

the leakage detection circuit comprises a first current coupling induction coil and a twelfth capacitor;

the twelfth capacitor is connected between a first terminal and a second terminal of the first current coupling induction coil;

the first and second terminals of the first current coupling induction coil are connected to the second and third pins of the leakage signal processing IC, respectively;

the live and neutral lines pass through the first current coupling induction coil;

the grounding detection circuit comprises a second current coupling induction coil and a thirteenth capacitor;

the thirteenth capacitor is connected to a first terminal and a second terminal of the second current coupling induction coil;

the first and second terminals of the second current coupling induction coil are grounded and connected to the leakage detection and signal amplifying circuit, respectively; and

the live and neutral lines pass through the second current coupling induction coil.

3. The ground fault protection circuit according to claim 2, wherein:

the leakage detection and signal amplifying circuit comprises the leakage signal processing IC, a fourteenth capacitor, a third resistor, and a fifteenth capacitor;

the fourteenth capacitor, the third resistor, and the fifteenth capacitor are sequentially connected in series between the first current coupling induction coil and the second current coupling induction coil;

the third resistor is connected between a fourth pin and a fifth pin of the leakage signal processing IC;

the signal shaping circuit comprises an operation amplifier, a sixteenth capacitor, a seventeenth capacitor, a fourth resistor, a fifth resistor, a sixth resistor, an eighteenth capacitor, a nineteenth capacitor, a twentieth capacitor, and a seventh resistor;

the sixteenth and seventeenth capacitors are connected in parallel between the ground and a sixth pin of the leakage signal processing IC;

the fourth resistor is connected between a sixth pin of the leakage signal processing IC and a first pin of the operation amplifier;

the fifth and sixth resistors are sequentially connected in series between the VCC and the ground;

a connection point of the fifth and sixth resistors is connected to a second pin of the operation amplifier;

the eighteenth capacitor and the sixth resistor are connected in parallel;

a power supply terminal and a ground terminal of the operation amplifier are respectively connected to the VCC and the ground;

the nineteenth capacitor is connected between the power supply terminal of the operation amplifier and the ground;

the seventh resistor and the twentieth capacitor are sequentially connected in series between the VCC and the ground;

a connection point of the seventh resistor and the twentieth capacitor is connected to a third pin of the operation amplifier;

the third pin of the operation amplifier is connected to a control signal input terminal the microcontroller;

the power supply detection circuit includes the first rectifier circuit, the first resistor, the internal regulator circuit, the third capacitor, an eighth resistor, a ninth resistor, a twenty-first capacitor, and the microcontroller;

the eighth resistor is connected between the first pin of the leakage signal processing IC and the ninth resistor, which is grounded;

a connection point of the eighth and ninth resistors is connected to a detection terminal of the microcontroller;

the twenty-first capacitor is connected between the ground and the detection terminal of the microcontroller;

the indicator circuit includes a normal signal output terminal and an error signal output terminal of the microcontroller, a tenth resistor, an eleventh resistor, a red LED, and a green LED;

the tenth resistor is connected between the error signal output terminal of the microcontroller and a negative electrode of the red LED;

the eleventh resistor connected between the normal signal output terminal of the microcontroller and a negative electrode of the green LED; and

a positive electrode of the red LED and a positive electrode of the green LED are connected to the VCC.

4. The ground fault protection circuit according to claim 3, wherein:

the control circuit of the tripping mechanism control circuit comprises the microcontroller, a twenty-second capacitor, a twelfth resistor, a first one-way silicon controlled rectifier, a twenty-third capacitor, a thirteenth resistor, and a relay that interfaces with the inductor coil;

the twenty-second capacitor is connected between a triggering signal terminal of the microcontroller and the ground;

the twelfth resistor is connected between the triggering signal terminal of the microcontroller and a control electrode of the first one-way silicon controlled rectifier;

an anode of the first one-way silicon controlled rectifier is connected to a connection point where the inductor coil is connected to of the second input terminal of the first rectifier circuit;

a cathode of the first one-way silicon controlled rectifier is grounded;

the twenty-third capacitor and the thirteenth resistor are connected in series between the anode of the first one-way silicon controlled rectifier and the ground;

the relay drives the reset switch through a mechanical link;

the reverse connection detection control circuit comprises the microcontroller, a twenty-fourth capacitor, a fourteenth resistor, a heavy and light current isolation optocoupler, a fifteenth resistor, a sixteenth resistor, and a two-way silicon controlled rectifier;

the twenty-fourth capacitor is connected between an SCR triggering terminal of the microcontroller and a ground terminal of the microcontroller;

the fourteenth resistor is connected between the SCR triggering terminal of the microcontroller and a triggering control terminal of the heavy and light current isolation optocoupler;

a power supply terminal of the heavy and light current isolation optocoupler is connected to the VCC;

the fifteenth resistor is connected between a first output terminal of the heavy and light current isolation optocoupler and a load output terminal of the live line;

the sixteenth resistor is connected between a control electrode and a first T2 electrode of the two-way silicon controlled rectifier;

the control electrode of the two-way silicon controlled rectifier is connected to a second output terminal of the heavy and light current isolation optocoupler;

a second T2 electrode of the two-way silicon controlled rectifier is connected to the load output terminal of the live line;

the detection and execution circuit comprises a twenty-fifth capacitor, a twenty-sixth capacitor, a normally-closed contact, a normally-open contact, a seventeenth resistor, a normally-closed switch, and a reverse relay;

the twenty-fifth capacitor and the twenty-sixth capacitor are connected in series;

the twenty-fifth capacitor is connected with the normally-closed contact, the normally-open contact, and the first T2 electrode of the two-way silicon controlled rectifier;

the twenty-sixth capacitor is connected with the load output terminal of the live line;

the seventeenth resistor is connected between a connection point between the twenty-fifth and twenty sixth capacitors and a load output terminal of the neutral line;

the normally-closed switch is provided on the live and neutral lines between the load output terminals of the live and neutral lines and the reset switch;

the normally-closed switch is linked with the normally-open contact;

a first terminal of the reverse relay is connected to the first T2 electrode of the two-way silicon controlled rectifier and a second terminal of the reverse relay is connected to the load output terminal of the neutral line; and

the reverse relay drives the normally-closed switch through a mechanical link.

5. The ground fault protection circuit according to claim 4, wherein:

the power supply circuit comprises a piezoresistor and an over-current protection resistor;

the piezoresistor is connected between the input terminal of the live line and the input terminal of the neutral line;

the over-current protection resistor is connected between the input terminal of the live line and an input terminal of the power supply filter circuit.

6. The ground fault protection circuit according to claim 1, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, an eighteenth resistor, a second one-way silicon controlled rectifier, and a nineteenth resistor;

the twenty-seventh capacitor is connected between ground and a signal triggering terminal of the microcontroller;

the eighteenth resistor is connected between the signal triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the nineteenth resistor are connected in series between the live line and the ground; and

the nineteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

7. The ground fault protection circuit according to claim 2, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, an eighteenth resistor, a second one-way silicon controlled rectifier, and a nineteenth resistor;

the twenty-seventh capacitor is connected between ground and a signal triggering terminal of the microcontroller;

the eighteenth resistor is connected between the signal triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the nineteenth resistor are connected in series between the live line and the ground; and

the nineteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

8. The ground fault protection circuit according claim 3, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, an eighteenth resistor, a second one-way silicon controlled rectifier, and a nineteenth resistor;

the twenty-seventh capacitor is connected between ground and a signal triggering terminal of the microcontroller;

the eighteenth resistor is connected between the signal triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the nineteenth resistor are connected in series between the live line and the ground; and

the nineteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

9. The ground fault protection circuit according to claim 4, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, an eighteenth resistor, a second one-way silicon controlled rectifier, and a nineteenth resistor;

the twenty-seventh capacitor is connected between ground and a signal triggering terminal of the microcontroller;

the eighteenth resistor is connected between the signal triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the nineteenth resistor are connected in series between the live line and the ground; and

the nineteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

10. The ground fault protection circuit according to claim 5, further comprising a simulation leakage circuit, wherein:

the simulation leakage circuit comprises the microcontroller, a twenty-seventh capacitor, an eighteenth resistor, a second one-way silicon controlled rectifier, and a nineteenth resistor;

the twenty-seventh capacitor is connected between ground and a signal triggering terminal of the microcontroller;

the eighteenth resistor is connected between the signal triggering terminal of the microcontroller and a control electrode of the second one-way silicon controlled rectifier;

the second one-way silicon controlled rectifier and the nineteenth resistor are connected in series between the live line and the ground; and

the nineteenth resistor is connected between an anode of the second one-way silicon controlled rectifier and the live line next to the reset switch.

11. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 3.

12. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 4.

13. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 5.

14. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 6.

15. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 7.

16. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 1.

17. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 2.

18. A ground fault circuit interrupter, comprising an interrupter body, wherein the interrupter body includes the ground fault protection circuit of claim 8.