CN214310827U - Grounding state detection circuit and electrical equipment - Google Patents
Grounding state detection circuit and electrical equipment Download PDFInfo
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- CN214310827U CN214310827U CN202023044151.7U CN202023044151U CN214310827U CN 214310827 U CN214310827 U CN 214310827U CN 202023044151 U CN202023044151 U CN 202023044151U CN 214310827 U CN214310827 U CN 214310827U
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Abstract
The embodiment of the utility model provides a relate to electrical apparatus safety technical field, disclose a ground connection state detection circuitry and electrical equipment, this circuit includes: the controller, the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler; the resistance-capacitance voltage reduction rectifying circuit comprises a first capacitor, a first diode and a second diode, wherein the anode of the first diode is connected with a live wire of a mains supply through the first capacitor, and the cathode of the first diode is connected with the input end of the photoelectric coupler; the cathode of the second diode is connected with a live wire of a mains supply through a first capacitor, and the anode of the second diode is connected with a ground wire; the input end of the photoelectric coupler is respectively connected with the cathode of the first diode and the ground wire of the ground, and the output end of the photoelectric coupler is connected with the controller; the controller is used for determining the grounding state of the earth ground wire according to the level signal at the output end of the photoelectric coupler. In this way, the embodiment of the utility model provides a whether function of ground connection of the earth ground wire that has realized detecting electrical apparatus improves the fail safe nature that electrical equipment used.
Description
Technical Field
The embodiment of the utility model provides a relate to electrical apparatus safety technical field, concretely relates to ground connection state detection circuitry and electrical equipment.
Background
At present, I-type electric appliances (such as washing machines, refrigerators, air conditioners, electric water heaters and the like) on the market generally have a safety protection circuit structure connected with the ground so as to prevent the electric appliances from damaging human bodies due to electric leakage. However, the home power utilization systems of many users have the phenomenon of imperfect grounding terminals or irregular wiring, so that the ground wire jacks of the electrical socket are not connected into the grounding same-bit line terminal rows. In this case, the safety protection circuit of the class I electrical appliance cannot be connected to the ground, which brings the safety risk of electric shock to the user when in use.
In the process of implementing the embodiment of the present invention, the inventor finds that: the prior art is lack of the function of detecting whether the earth ground wire of an electric appliance is grounded.
SUMMERY OF THE UTILITY MODEL
In view of the above problem, the embodiment of the utility model provides a ground connection state detection circuitry and electrical equipment for solve the problem that whether ground connection's the detection function lacks to electrical apparatus earth ground wire that exists among the prior art.
According to the utility model discloses an aspect of the embodiment provides a ground connection state detection circuitry, include: the controller, the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler;
the resistance-capacitance voltage reduction rectifying circuit comprises a first capacitor, a first diode and a second diode, wherein the anode of the first diode is connected with a live wire of a mains supply through the first capacitor, and the cathode of the first diode is connected with the input end of the photoelectric coupler; the negative electrode of the second diode is connected with a live wire of a mains supply through the first capacitor, and the positive electrode of the second diode is connected with a ground wire;
the input end of the photoelectric coupler is respectively connected with the cathode of the first diode and the earth ground wire, and the output end of the photoelectric coupler is connected with the controller;
and the controller is used for determining the grounding state of the earth ground wire according to the level signal at the output end of the photoelectric coupler.
In an optional manner, the ground state detection circuit further includes a second capacitor, one end of the second capacitor is connected to the negative electrode of the first diode, and the other end of the second capacitor is connected to the earth ground.
In an optional mode, the ground state detection circuit further includes a zener diode and a first resistor; and the cathode of the voltage stabilizing diode is connected with the cathode of the first diode, and the anode of the voltage stabilizing diode is connected with the earth ground wire through the first resistor.
In an alternative mode, the connecting the input end of the photoelectric coupler with the cathode of the first diode and the earth ground respectively includes: a first pin at the input end of the photoelectric coupler is connected with the negative electrode of the first diode, and a second pin at the input end of the photoelectric coupler is connected with the earth ground wire;
the output end is connected with the controller and comprises: and a third pin of the output end of the photoelectric coupler is respectively connected with the second detection end of the controller and the ground wire of the circuit power supply, and a fourth pin of the output end of the photoelectric coupler is respectively connected with the first detection end of the controller and the VDD end of the circuit power supply.
In an optional mode, the ground state detection circuit further includes a second resistor, one end of the second resistor is connected to the negative electrode of the first diode, and the other end of the second resistor is connected to the first pin of the input end of the photoelectric coupler.
In an optional mode, the ground state detection circuit further includes a third resistor, one end of the third resistor is connected to a fourth pin of the output terminal of the photoelectric coupler, and the other end of the third resistor is connected to the VDD terminal of the circuit power supply.
In an optional mode, the ground state detection circuit further includes a fourth resistor, one end of the fourth resistor is connected to a fourth pin of the output end of the photoelectric coupler, and the other end of the fourth resistor is connected to the first detection end of the controller.
In an alternative mode, the determining the grounding state of the earth ground according to the level signal at the output end of the photoelectric coupler includes:
the controller judges that the earth ground wire is in a ground disconnection state when detecting that the level of the first detection end is always a first reference value which is larger than the level of the second detection end;
the controller detects that the level of the first detection end periodically fluctuates between the first reference value and the second reference value, and then judges that the earth ground wire is in a ground connection state; the second reference value is smaller than the first reference value.
In an optional mode, the controller comprises a command output end for sending out a device grounding failure prompt when the earth ground wire is judged to be in a state of being disconnected with the earth.
According to another aspect of the embodiments of the present invention, there is provided an electric apparatus including the above-described ground state detection circuit.
The embodiment of the utility model provides a ground connection state detection circuitry, which comprises a controller, resistance-capacitance step-down rectifier circuit and optoelectronic coupler, at the commercial power live wire, resistance-capacitance step-down rectifier circuit, form the return circuit between optoelectronic coupler and the ground wire, when the ground wire is in different ground connection states, optoelectronic coupler exports different level signal to the controller, can confirm the ground connection state of ground wire fast through this level signal controller, thereby realized the function whether ground connection is gone to ground of ground wire that detects electrical apparatus, improve the fail safe nature that electrical equipment used.
The above description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented according to the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the present invention is given.
Drawings
The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a circuit schematic diagram of a ground state detection circuit provided by an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.
The embodiment of the utility model provides a scene that mainly is applied to ground wire ground connection state to electrical equipment and carries out the detection. Fig. 1 shows a circuit schematic diagram of a ground state detection circuit provided by an embodiment of the present invention. As shown in fig. 1, the ground state detection circuit includes: the controller, the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler U1;
the resistance-capacitance voltage reduction rectifying circuit comprises a first capacitor, a first diode D1 and a second diode D2, wherein the anode of the first diode D1 is connected with the live wire of the mains supply through the first capacitor, and the cathode of the first diode D1 is connected with the input end of the photoelectric coupler U1; the cathode of the second diode D2 is connected to the live wire of the commercial power through the first capacitor, and the anode of the second diode D2 is connected to the earth ground EGND;
the input end of the photoelectric coupler U1 is respectively connected with the negative electrode of the first diode D1 and the earth ground wire, and the output end of the photoelectric coupler U1 is connected with the controller;
when the earth ground wire is connected with the earth, the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler U1 form a loop, the photoelectric coupler U1 is conducted, and a waveform level signal is output to the controller; when the earth ground wire is disconnected with the earth, a loop formed by the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler U1 is disconnected, the photoelectric coupler U1 is cut off, and a constant level signal is output to the controller;
and the controller is used for determining the grounding state of the earth ground wire according to the level signal at the output end of the photoelectric coupler U1.
Specifically, the controller may be a main control chip such as an MCU (micro controller Unit), a single chip microcomputer, or a processor. The power line of the commercial power is generally the power line of the power grid house-entering power AC220V or AC380V, and of course, the voltage and frequency of the commercial power may be different in different countries. The earth ground is a line used for connecting with a ground terminal in a socket in electrical equipment.
Specifically, the first capacitor may be the capacitor CY1 or the capacitor CY2 in fig. 1. In fig. 1, the live wire is a line connected with the live terminal of the socket in the electrical equipment, and the zero wire is a line connected with the zero terminal of the socket in the electrical equipment. When the live wire terminal and the zero wire terminal in the socket are correctly specified and connected to the mains supply, the first capacitor is a capacitor CY1, and the anode of the first diode D1 and the cathode of the second diode D2 are connected to the live wire of the mains supply through the capacitor CY 1; when the live wire terminal and the zero line terminal in the socket are reversely connected to the mains supply, i.e. the live wire terminal in the socket is actually the zero line of the mains supply, the zero line terminal is actually the live wire of the mains supply, the first capacitor is a capacitor CY2, and the anode of the first diode D1 and the cathode of the second diode D2 are connected with the live wire of the mains supply through the capacitor CY 2. Thus, in practical use, the ground state detection circuit can operate normally regardless of the connection condition of the terminals in the socket. Preferably, the capacitor CY1 and the capacitor CY2 are Y1 or Y2 series of safety capacitors, so as to further improve the safety of the circuit. In addition, due to the existence of the safety capacitors CY1 and CY2, the live wire and the zero wire cannot be short-circuited and the passing current is small. Of course, the zero line and the capacitor CY2 in fig. 1 may be omitted.
In an optional embodiment, the ground state detection circuit further includes a second capacitor C1, and one end of the second capacitor C1 is connected to the negative electrode of the first diode D1, and the other end is connected to the earth ground. The second capacitor C1 can perform a filtering function, so that the level signal output by the photocoupler U1 is more regular, and the controller can detect the level signal conveniently.
In an optional embodiment, the ground state detection circuit further includes a zener diode ZD1 and a first resistor R1; the cathode of the zener diode ZD1 is connected to the cathode of the first diode D1, and the anode is connected to the earth ground through the first resistor R1. The voltage stabilizing diode ZD1 and the first resistor R1 form an amplitude limiting voltage stabilizing circuit so as to limit abnormal voltage in the circuit and prevent the photoelectric coupler U1 from being damaged by overlarge voltage. The first resistor R1 is a current-limiting resistor, and is an optional component, and plays a role in current-limiting protection for the zener diode ZD 1.
In an alternative embodiment, the connection of the input terminal of the photocoupler U1 with the negative terminal of the first diode D1 and the earth ground respectively includes: a first pin at the input end of the photoelectric coupler U1 is connected with the negative electrode of the first diode D1, and a second pin at the input end is connected with the earth ground wire;
the output end is connected with the controller and comprises: and a third pin of an output end of the photoelectric coupler U1 is respectively connected with a second detection end of the controller and a circuit power supply ground wire GND, and a fourth pin of the output end is respectively connected with a first detection end of the controller and a VDD end of the circuit power supply.
Specifically, the VDD terminal of the circuit power supply may be connected to the positive terminal of the circuit power supply, and the ground of the circuit power supply may be connected to the negative terminal of the circuit power supply. It is common that the level value at the VDD end is 5V or 3.3V, and the level value at the GND end is 0V, but the level values may be flexibly adjusted according to specific situations, and the level values are not limited herein.
In an optional embodiment, the ground state detection circuit further includes a second resistor R2, and one end of the second resistor R2 is connected to the negative electrode of the first diode D1, and the other end is connected to the first pin of the input terminal of the photocoupler U1. The second resistor R2 is a current limiting resistor, and plays a role in current limiting protection for the input terminal of the photoelectric coupler U1.
In an optional embodiment, the ground state detection circuit further includes a third resistor R3, wherein one end of the third resistor R3 is connected to the fourth pin of the output terminal of the photocoupler U1, and the other end of the third resistor R3 is connected to the VDD terminal of the circuit power supply. The second resistor R3 is also a current limiting resistor, and plays a role in current limiting protection for the output terminal of the optocoupler U1.
In an optional embodiment, the ground state detection circuit further includes a fourth resistor R4, where one end of the fourth resistor R4 is connected to the fourth pin of the output terminal of the photocoupler U1, and the other end of the fourth resistor R4 is connected to the first detection terminal of the controller. The second resistor R4 is also a current limiting resistor, and plays a role in current limiting protection for the controller.
In an alternative embodiment, the determining the grounding state of the earth ground according to the level signal at the output end of the photocoupler U1 includes:
the controller judges that the earth ground wire is in a ground disconnection state when detecting that the level of the first detection end is always a first reference value which is larger than the level of the second detection end;
the controller detects that the level of the first detection end periodically fluctuates between the first reference value and the second reference value, and then judges that the earth ground wire of the commercial power interface is in a state of being connected with the earth; the second reference value is smaller than the first reference value.
In an optional embodiment, the controller comprises a command output end for sending out a device grounding failure prompt when the earth ground wire is judged to be in a state of being disconnected from the earth.
Specifically, the principle of detecting and determining the grounding state of the earth ground by the controller is as follows:
1. in the case where the earth ground is disconnected from earth.
For example, the conductors A, B of the earth ground in fig. 1 are disconnected. At this time, a loop formed by the live wire of the mains supply, the resistance-capacitance step-down rectifying circuit, the photoelectric coupler U1 and the earth ground is disconnected, no current passes through the light emitting diode in the photoelectric coupler U1, the photoelectric coupler U1 is cut off, and the level signal output by the fourth pin of the output end of the photoelectric coupler is a constant signal, namely the level signal detected by the first detection end of the controller is always a first reference value. Typically, the first reference value is a level of the VDD terminal of the circuit power supply, for example, 5V or 3.3V. However, due to losses in the circuit, the first reference value may also be slightly lower than the level at the VDD terminal of the circuit power supply, e.g. 4.5V or 3V. That is, the first reference value may be a voltage range, and may be flexibly set according to practical situations, which is not limited herein. The level signal detected by the second detection terminal is a circuit power ground level, for example, 0V. Therefore, the controller detects that the level of the first detection end is always the first reference value which is larger than the level of the second detection end, and the earth ground wire can be judged to be in the state of being disconnected with the earth.
2. In the case where the above-described earth ground is connected to earth.
For example, the conductors at both ends A, B of the earth ground in FIG. 1 are closed. At this time, the live wire of the commercial power, the resistance-capacitance step-down rectification circuit, the photocoupler U1 and the ground wire form a loop. Because the rectified resistance-capacitance voltage reduction rectifying circuit is 50Hz/60Hz pulse direct current, when the second capacitor C1 does not exist, the pulse direct current directly drives a light emitting diode in the photoelectric coupler U1 through the second resistor R2, and the photoelectric coupler U1 is periodically switched on and off; under the condition that the second capacitor C1 exists, the pulse direct current charges the second capacitor C1, when the charge charged by the second capacitor C1 reaches the LED conduction condition in the photoelectric coupler U1 through the second resistor R2, the photoelectric coupler U1 is conducted, and when the charge charged by the second capacitor C1 does not reach the LED conduction condition in the photoelectric coupler U1, the photoelectric coupler U1 is cut off, namely the photoelectric coupler U1 is periodically conducted and cut off. When the photoelectric coupler U1 is cut off, the first detection end of the controller detects that the level signal is the first reference value; when the photoelectric coupler U1 is turned on, the first detection end of the controller detects that the level signal is the second reference value. That is, as the photocoupler U1 switches between on and off states, the fourth pin of its output terminal outputs a waveform level signal that periodically changes between the first reference value and the second reference value. Typically, the second reference value is a ground level value of the circuit power supply, for example, 0V. However, due to the performance differences of the components in the circuit, the second reference value may be slightly higher than the ground level of the power supply of the circuit, for example, 0.5V or 0.3V. That is, the second reference value may be a voltage range, and may be flexibly set according to practical situations, which is not limited herein. Therefore, when the controller detects that the level of the first detection terminal periodically fluctuates between the first reference value and the second reference value, for example, in the case of the second capacitor C1, the controller detects a 50Hz/60Hz square wave at the first detection terminal, and then the earth-ground wire can be determined to be in the earth connection state.
Furthermore, when the controller judges that the earth ground wire in the electrical equipment is in a disconnection state with the earth, a prompt of poor grounding of the equipment is sent to a user, the user is guided to check earth ground wire faults, and the electrical equipment can be directly controlled to be powered off through the command output end, so that the electric shock risk is reduced. When the controller judges that the earth ground wire in the electrical equipment is in a state of being connected with the earth ground, the power supply can be switched on, and the working state of the equipment is recovered.
The embodiment of the utility model provides a ground connection state detection circuitry, which comprises a controller, resistance-capacitance step-down rectifier circuit and optoelectronic coupler, at the commercial power live wire, resistance-capacitance step-down rectifier circuit, form the return circuit between optoelectronic coupler and the ground wire, when the ground wire is in different ground connection states, optoelectronic coupler exports different level signal to the controller, can confirm the ground connection state of ground wire fast through this level signal controller, thereby realized the function whether ground connection is gone to ground of ground wire that detects electrical apparatus, improve the fail safe nature that electrical equipment used.
The embodiment of the utility model provides an electrical equipment, the ground connection state detection circuitry who provides including above-mentioned embodiment possesses corresponding functional module and beneficial effect. The electrical equipment can be I-type electrical equipment such as washing machines, refrigerators, air conditioners, electric water heaters, dish washing machines and the like. The technical details that are not described in detail in this embodiment can be referred to the embodiment of the ground fault detection circuit provided by the present invention, and are not described herein again.
It should be noted that unless otherwise indicated, technical or scientific terms used in accordance with embodiments of the present invention shall have the ordinary meaning as understood by those skilled in the art to which embodiments of the present invention pertain.
In the description of the embodiments of the present invention, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship indicated on the drawings, which is only for convenience of describing the embodiments of the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the embodiments of the present invention.
Furthermore, the technical terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.
In the description of the novel embodiments of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the embodiments of the present invention can be understood by those skilled in the art according to specific situations.
In describing the novel embodiments of this embodiment, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present invention is not limited to the particular embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.
Claims (9)
1. A ground state detection circuit, comprising: the controller, the resistance-capacitance voltage reduction rectifying circuit and the photoelectric coupler;
the resistance-capacitance voltage reduction rectifying circuit comprises a first capacitor, a first diode and a second diode, wherein the anode of the first diode is connected with a live wire of a mains supply through the first capacitor, and the cathode of the first diode is connected with the input end of the photoelectric coupler; the negative electrode of the second diode is connected with a live wire of a mains supply through the first capacitor, and the positive electrode of the second diode is connected with a ground wire;
the input end of the photoelectric coupler is respectively connected with the cathode of the first diode and the earth ground wire, and the output end of the photoelectric coupler is connected with the controller;
and the controller is used for determining the grounding state of the earth ground wire according to the level signal at the output end of the photoelectric coupler.
2. The ground state detection circuit according to claim 1, further comprising a second capacitor having one end connected to the negative electrode of the first diode and the other end connected to the earth ground.
3. The ground state detection circuit of claim 1, further comprising a zener diode and a first resistor; and the cathode of the voltage stabilizing diode is connected with the cathode of the first diode, and the anode of the voltage stabilizing diode is connected with the earth ground wire through the first resistor.
4. The ground state detection circuit of claim 1, wherein a first pin of an input terminal of the photocoupler is connected to a negative electrode of the first diode, and a second pin of the input terminal is connected to the earth ground; and a third pin of the output end of the photoelectric coupler is respectively connected with the second detection end of the controller and the ground wire of the circuit power supply, and a fourth pin of the output end of the photoelectric coupler is respectively connected with the first detection end of the controller and the VDD end of the circuit power supply.
5. The ground state detection circuit of claim 4, further comprising a second resistor, wherein one end of the second resistor is connected to the negative electrode of the first diode, and the other end of the second resistor is connected to the first pin of the input terminal of the photocoupler.
6. The ground state detection circuit of claim 4, further comprising a third resistor, wherein one end of the third resistor is connected to the fourth pin of the output terminal of the photocoupler, and the other end of the third resistor is connected to the VDD terminal of the circuit power supply.
7. The ground state detection circuit of claim 4, further comprising a fourth resistor, wherein one end of the fourth resistor is connected to the fourth pin of the output terminal of the photocoupler, and the other end of the fourth resistor is connected to the first detection terminal of the controller.
8. The ground condition detection circuit of claim 1, wherein the controller includes a command output for issuing a device poor ground indication when the earth ground is determined to be in an earth-disconnected state.
9. An electrical apparatus, characterized in that it comprises a ground state detection circuit according to any one of claims 1 to 8.
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| CN202023044151.7U CN214310827U (en) | 2020-12-16 | 2020-12-16 | Grounding state detection circuit and electrical equipment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114113848A (en) * | 2021-11-24 | 2022-03-01 | 珠海格力电器股份有限公司 | Ground wire detection device, washing machine and ground wire detection method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114113848A (en) * | 2021-11-24 | 2022-03-01 | 珠海格力电器股份有限公司 | Ground wire detection device, washing machine and ground wire detection method thereof |
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