CN117374883A

CN117374883A - Leakage protection device, electric connection equipment and electric appliance

Info

Publication number: CN117374883A
Application number: CN202311333130.2A
Authority: CN
Inventors: 李成力; 陈龙
Original assignee: Suzhou Ele Mfg Co ltd
Current assignee: Suzhou Ele Mfg Co ltd
Priority date: 2023-10-16
Filing date: 2023-10-16
Publication date: 2024-01-09

Abstract

The invention provides a leakage protection device, which comprises a switch module, a control module and a control module, wherein the switch module is configured to control electric power connection between an input end and an output end; a leakage detection module configured to detect a leakage current signal on the current carrying line and generate a leakage fault signal when the leakage current signal is detected; an over-temperature protection module configured to detect a temperature of a specific location and/or a specific element in the earth leakage protection device and generate an over-temperature fault signal when the detected temperature exceeds a preset threshold; a drive module configured to drive the switch module to disconnect the power connection in response to a leakage fault signal and/or an over-temperature fault signal; and the self-checking module is configured to periodically generate a simulated leakage current signal and generate a self-checking fault signal when the leakage current detection module and/or the driving module fail. The invention cuts off the power connection in time when the temperature rises due to the failure of the device, avoids the occurrence of danger and further increases the safety.

Description

Leakage protection device, electric connection equipment and electric appliance

Technical Field

The invention relates to the field of electric appliances, in particular to a leakage protection device, electric connection equipment and an electric appliance.

Background

With the increasing awareness of safety, more and more households choose to install earth leakage protection devices in houses, including Ground Fault Circuit Interrupters (GFCIs), earth leakage protectors (ALCIs), mobile earth leakage Protectors (PRCDs), and the like.

However, the current leakage protection device has only a single leakage protection function, and when other faults occur in the line, such as overload or overheat of the plug blade, a significant safety hazard is brought about, and danger may occur.

Disclosure of Invention

Based on the above-mentioned problems, a first aspect of the present invention proposes a leakage protection device, comprising: a switching module coupled between an input and an output of a current carrying line and configured to control a power connection between the input and the output; a leakage detection module configured to detect a leakage current signal on the current carrying line and generate a leakage fault signal when the leakage current signal is detected; an over-temperature protection module configured to detect a temperature of a specific location and/or a specific element in the earth leakage protection device and generate an over-temperature fault signal when the temperature is detected to exceed a preset threshold; a drive module coupled to the switch module, the leakage detection module, and the over-temperature protection module and configured to receive the leakage fault signal and/or the over-temperature fault signal and drive the switch module to disconnect the power connection in response to the leakage fault signal and/or the over-temperature fault signal; a self-test module coupled to the leakage detection module and the drive module and configured to periodically generate the simulated leakage current signal to detect whether the leakage detection module and/or the drive module is malfunctioning and to generate a self-test fault signal when the leakage detection module and/or the drive module is malfunctioning.

In some embodiments, the over-temperature protection module includes at least one temperature sensor disposed at the particular location and/or the particular component surface.

In some embodiments, the at least one temperature sensor includes a thermistor, a diode, and/or a bi-metallic strip switch.

In some embodiments, the at least one temperature sensor comprises a thermistor, the over-temperature protection module comprises a first voltage trigger sub-module and at least one voltage dividing element connected in series with the thermistor and coupled to the first voltage trigger sub-module, the first voltage trigger sub-module further coupled to the drive module, wherein when the thermistor detects that the temperature of the particular location and/or the particular element exceeds the preset threshold, the at least one voltage dividing element provides an over-temperature detection signal to the first voltage trigger sub-module, thereby causing the first voltage trigger module to generate the over-temperature fault signal.

In some embodiments, the over-temperature protection module further includes a voltage stabilizing element, and the first voltage dividing element is connected in series with the thermistor and then connected in parallel with the voltage stabilizing element.

In some embodiments, the first voltage trigger submodule includes a trigger diode, a transistor, a field effect transistor, and/or a comparator.

In some embodiments, the at least one temperature sensor includes a bimetal switch coupled to the drive module, the bimetal switch being closed when the bimetal switch detects that the particular position and/or the temperature of the particular element exceeds the preset threshold, thereby generating the over-temperature fault signal.

In some embodiments, the self-test module includes a second voltage trigger sub-module and a first capacitor connected in series, and the first capacitor is charged by the current-carrying line and periodically generates the simulated leakage current signal via the second voltage trigger sub-module.

In some embodiments, the second voltage trigger submodule includes a trigger diode, a transistor, a field effect transistor, and/or a comparator.

In some embodiments, the leakage protection device further comprises a monitoring module coupled to the leakage detection module and comprising a test switch, and configured to generate the simulated leakage current signal when the test switch is operated to detect whether the leakage protection device is operating properly.

A second aspect of the present invention proposes an electrical connection device comprising: a housing; and a leakage protection device according to any one of the embodiments of the first aspect, the leakage protection device being housed in the housing.

A third aspect of the present invention proposes an electrical appliance comprising: a load device; and an electrical connection device coupled between the current carrying line and the load device for supplying power to the load device, wherein the electrical connection device comprises a leakage protection apparatus according to any of the embodiments of the first aspect.

According to the invention, the over-temperature protection module is added in the leakage protection device, so that the power connection can be cut off in time when the temperature in the leakage protection device rises due to overload of a circuit or poor contact of plug blades, thereby avoiding danger, eliminating potential safety hazards and further increasing the safety of the leakage protection device. In addition, the leakage protection device provided by the invention has the advantages of simple circuit structure, low cost and high safety.

Drawings

The embodiments are shown and described with reference to the drawings. The drawings serve to illustrate the basic principles and thus only show aspects necessary for understanding the basic principles. The figures are not to scale. In the drawings, like reference numerals refer to like features. In addition, a connection between each frame in the architecture diagram indicates that there is an electrical coupling between two frames, and the absence of a connection between two frames does not indicate that the two frames are not coupled.

Fig. 1 shows a schematic configuration diagram of an earth leakage protection device according to an embodiment of the present invention;

fig. 2 shows a schematic diagram of a first embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 3 shows a schematic diagram of a second embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 4 shows a schematic diagram of a third embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 5 shows a schematic diagram of a fourth embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 6 shows a schematic diagram of a fifth embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 7 shows a schematic diagram of a sixth embodiment of the earth leakage protection device according to an embodiment of the present invention;

fig. 8 shows a structural view of an electrical connection apparatus according to an embodiment of the present invention; and

fig. 9 shows another structural diagram of an electrical connection apparatus according to an embodiment of the present invention.

Detailed Description

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings illustrate, by way of example, specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Before describing embodiments of the present invention, some of the terms involved in the present invention will be explained first for better understanding of the present invention.

The terms "connected" or "coupled" and the like as used herein are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "a," "an," "a group," or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one.

The terms "comprising," including, "and similar terms used herein should be construed to be open-ended terms, i.e., including, but not limited to," meaning that other elements may also be included. The term "based on" is based at least in part on. The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment," and so forth. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

The invention aims to provide an electric leakage protection device. The over-temperature protection module is added in the leakage protection device, and when the temperature inside the leakage protection device rises due to overload or poor contact of the plug blades, the power connection can be cut off in time, so that the danger is avoided, the potential safety hazard is eliminated, and the safety of the leakage protection device is further improved. In addition, the leakage protection device provided by the invention has the advantages of simple circuit structure, low cost and high safety.

Fig. 1 shows a schematic configuration diagram of an earth leakage protection device according to an embodiment of the present invention. As shown in fig. 1, the earth leakage protection device 100 includes a switching module 103, an earth leakage detection module 104, an over-temperature protection module 105, and a driving module 106. The switching module 103 is coupled between the input 101 and the output 102 of the power line and controls the electrical connection between the input 101 and the output 102 of the current line. The current lines may comprise a first current line (L) for connection to a grid hot line and a second current line (N) for connection to a grid neutral line. The leakage detection module 104 detects a leakage current signal on the current carrying line and generates a leakage fault signal when the leakage current signal is detected. The over-temperature protection module 105 detects a temperature of a particular location and/or a particular element in the earth leakage protection device 100 and generates an over-temperature fault signal when the detected temperature exceeds a preset threshold. The driving module 106 is coupled to the switching module 103, the leakage detection module 104 and the over-temperature protection module 105, receives the leakage fault signal and/or the over-temperature fault signal, and drives the switching module 103 to disconnect the power connection in response to the leakage fault signal and/or the over-temperature fault signal.

The leakage protection device 100 of the embodiment includes an over-temperature protection module, and when the circuit is overloaded or the internal temperature of the leakage protection device rises due to poor contact of the plug blades, the power connection can be cut off in time, so that the danger is avoided, the potential safety hazard is eliminated, and the safety of the leakage protection device is further increased. In addition, the leakage protection device provided by the invention has the advantages of simple circuit structure, low cost and high safety.

In some embodiments, the over-temperature protection module 105 includes at least one temperature sensor disposed at a particular location and/or a particular component surface. The at least one temperature sensor may be a thermistor, diode and/or a bi-metallic strip switch. A temperature sensor may be used to detect the temperature of a particular location and/or a particular component to reduce cost and reduce the size of the earth leakage protection device. Alternatively, more than one temperature sensor may be used to detect the temperature of a specific location and/or a specific element, for example, to detect the temperature of different locations and/or different elements, and then the detection result is processed to obtain a final detection result, so as to improve the detection accuracy.

In some embodiments, the at least one temperature sensor comprises a thermistor. The over-temperature protection module 105 includes a first voltage triggering sub-module and at least one voltage dividing element. At least one voltage dividing element is connected in series with the thermistor and coupled to the first voltage triggering sub-module. The first voltage trigger sub-module is also coupled to the drive module 106. When the thermistor detects that the temperature of the specific position and/or the specific element exceeds a preset threshold value, the at least one voltage dividing element provides an over-temperature detection signal for the first voltage triggering sub-module, so that the first voltage triggering module generates an over-temperature fault signal. The voltage dividing element may be, for example, a resistor, an inductor or a capacitor.

In some embodiments, the over-temperature protection module further includes a voltage stabilizing element, and the first voltage dividing element is connected in parallel with the voltage stabilizing element after being connected in series with the thermistor. By adding the voltage stabilizing element, the voltage at the two ends of the first voltage dividing element and the thermistor can be kept stable, so that the accuracy of the temperature preset threshold value is improved. The first voltage triggering submodule includes a triggering diode, a third transistor, a field effect transistor, and/or a comparator.

In some embodiments, the at least one temperature sensor includes a bimetal switch coupled to the drive module, the bimetal switch being closed when the bimetal switch detects that a particular location and/or a temperature of a particular element exceeds a preset threshold, thereby generating an over-temperature fault signal.

In some embodiments, the leakage protection device further includes a self-test module coupled to the leakage detection module and the drive module and configured to periodically generate a simulated leakage current signal to detect if the leakage detection module and/or the drive module fails and to generate a self-test failure signal when the leakage detection module and/or the drive module fails.

In some embodiments, the self-test module includes a second voltage trigger sub-module and a first capacitor connected in series. The first capacitor is charged by the current carrying line and periodically generates an analog leakage current signal via the second voltage trigger sub-module. The second voltage trigger submodule includes a trigger diode, a third tube, a field effect tube and/or a comparator.

In some embodiments, the earth-leakage protection device 100 further includes a monitoring module coupled to the earth-leakage detection module 104 and including a test switch, and generates a simulated earth-leakage fault signal when the test switch is operated to detect whether the earth-leakage protection device is operating properly.

Fig. 2 shows a schematic diagram of a first embodiment of the earth leakage protection device according to the present invention.

As shown in fig. 2, the leakage protection device 200 is coupled between the input terminal LINE and the LOAD device LOAD, and includes a switching module 103, a leakage detection module 104, an over-temperature protection module 105, a driving module 106, a self-checking module 107, and a monitoring module 108. The current lines include a first current line L (HOT) 11 and a second current line N (WHITE) 12. The leakage detection module 104 includes a zero sequence current transformer ZCT1, a leakage detection chip U1, and peripheral circuits thereof, and the first current line 11 and the second current line 12 pass through the zero sequence current transformer ZCT1. The switch module 103 includes a RESET switch RESET for controlling the on-off of the power connection of the current line. The over-temperature protection module 105 mainly includes diodes D2 and D3 connected in parallel, a resistor R6, a thermistor T1, and a resistor R10 (first voltage dividing element) connected in series, and a trigger diode ZD1 (first voltage trigger sub-module). The driving module 106 includes a switch driving element (e.g., solenoid SOL), two thyristors Q1 and Q2, and an auxiliary switch SW1. The auxiliary switch SW1 and the RESET switch RESET are linked switches. The self-checking module 107 includes a trigger diode ZD2, a capacitor C7 (first capacitor), a thyristor Q3, a resistor R7, a capacitor C4, a light emitting diode LED1 connected in parallel with the resistor R7 and the capacitor C4 and connected in series with the capacitor C7, and some peripheral components. In other embodiments, the thyristors Q3 may be omitted, and the thyristors Q1 and/or Q2 may be shared with the driver module 106, i.e., the thyristors Q1 and/or Q2 may be connected in parallel with the capacitor C7 to provide a charge draining path for the capacitor C7 when turned on. The monitoring module 108 includes a resistor R1 and a TEST switch TEST connected in series.

In the leakage current detection, the leakage protection device 200 closes both the RESET switch RESET and the auxiliary switch SW1. When the first current carrying line 11 and the second current carrying line 12 are current balanced, the zero sequence current transformer ZCT1 does not generate an unbalanced current. When a leakage current exists on the first current carrying line 11 or the second current carrying line 12, the zero sequence current transformer ZCT1 detects the leakage current signal, and the secondary side generates a corresponding induction signal. The zero sequence current transformer ZCT1 is coupled to the leakage detection chip U1, and the induction signal is transmitted to the leakage detection chip U1 for processing. When the value of the processed leakage current is greater than the set threshold, the pin 1 of the leakage detection chip U1 outputs a high level (leakage fault signal), otherwise outputs a low level. The high level of the pin 1 of the leakage detection chip U1 is supplied to the control electrodes of the thyristors Q1 and Q2 via the diode D6 and the resistor R13, triggering the thyristors Q1 and/or Q2 to conduct, thereby generating a current change on the coil of the solenoid SOL, and thus generating an electromagnetic force, and the RESET switch RESET of the driving switch module 103 disconnects the electrical connection between the input terminal and the output terminal of the current line, while the auxiliary switch SW disconnects.

The leakage protection device 200 also has a self-checking function. The current charges the capacitor C7 through the first current carrying line 11-D2/D3-R14, and as the voltage across the capacitor C7 increases, the voltage across the trigger diode ZD2 increases. After a preset period of time, the voltage across the trigger diode ZD2 reaches the trigger voltage, the trigger diode ZD2 is turned on, current flows through the C7-LEDs 1-R4 to generate a simulated leakage current, and at the same time, power is supplied to the leakage detection chip U1 via the R8-D4 (in the negative half cycle), and the capacitor C8 is charged via the resistors R9-R13. In the normal working state of the leakage protection device 200, that is, the leakage detection module 104 and the driving module 105 work normally, if the zero sequence current transformer ZCT1 detects the simulated leakage current, the secondary end generates a corresponding induction signal and transmits the induction signal to the leakage detection chip U1, the pin 1 of the leakage detection chip U1 outputs a high level, and the thyristor Q3 is triggered to be turned on. At this time, the capacitor C7 rapidly releases the power through the thyristor Q3-SOL, the voltage at both ends rapidly drops, and when the voltage drops to be smaller than the trigger voltage of the trigger diode ZD2, the trigger diode ZD2 is turned off. The time of this process is shorter, and by presetting the capacities of the capacitors C4 and C8, the voltages at the two ends of the capacitors C4 and C8 are slowly increased in this process, and are both at a lower level, which is insufficient to trigger the light emitting diode LED1 to light up, and insufficient to trigger the thyristors Q1 and Q2 to turn on, so that the normal operation of the leakage protection device 200 is not affected. Thus, during this process, the light emitting diode LED1 is not lit, nor is the switch module 103 opened, but remains in the closed state.

When the leakage detection module 104 fails and the simulated leakage current cannot be detected, the pin 1 of the leakage detection chip U1 is kept at a low level, the thyristor Q3 cannot be triggered to conduct, the capacitor C7 cannot rapidly release electric quantity through the thyristor Q3 and the solenoid SOL, the trigger diode ZD2 is triggered to conduct for a long time, and the current continuously charges the capacitors C4 and C8 through the capacitors C7, C6, R9 and R13 (i.e. generates a self-checking fault signal), so that voltages at two ends of the capacitors C4 and C8 rise to a certain level, which is sufficient to trigger the light emitting diode LED1 to light and trigger the thyristors Q1 and Q2 to conduct. At this time, the light emitting diode LED1 is turned on (i.e., an alarm signal is emitted). If the driving module 105 works normally, the thyristors Q1 and/or Q2 are turned on, so that a current change is generated in the coil of the solenoid SOL, and thus an electromagnetic force is generated, and the RESET switch RESET of the driving switch module 103 disconnects the power connection between the input terminal and the output terminal of the current line. If the drive module 105 also fails, such as a solenoid SOL opens, the switch module 103 remains in the closed state.

When the leakage detection module 104 works normally and the driving module 105 fails, for example, the solenoid SOL is broken, the zero sequence current transformer ZCT1 detects the simulated leakage current, the secondary side generates a corresponding induction signal and transmits the induction signal to the leakage detection chip U1, the pin 1 of the leakage detection chip U1 outputs a high level, and the thyristor Q3 is triggered to be turned on. Because the solenoid SOL is open, the capacitor C7 cannot rapidly discharge electric quantity through the thyristor Q3 and the solenoid SOL, the trigger diode ZD2 is turned on for a long time, and the current continuously charges the capacitors C4 and C8 through the capacitors C7, C6, R9 and R13 (i.e. generates a self-checking fault signal), so that the voltages at the two ends of the capacitors C4 and C8 rise to a certain level, which is sufficient to trigger the light emitting diode LED1 to light (i.e. send an alarm signal) and trigger the thyristors Q1 and Q2 to be turned on. At this time, the light emitting diode LED1 is turned on, and the switch module 103 is maintained in a closed state.

With further discharge of the capacity C7, the trigger diode ZD2 is turned off, and the light emitting diode LED1 is turned off. The current charges the capacitor C7 again through the first current carrying line 11-D2/D3-R14, and as the voltage across the capacitor C7 increases again, the trigger diode ZD2 turns on again, and the light emitting diode LED1 also lights up again. And repeating the steps, finally, presenting the state that the LED flashes, namely, sending out a flashing light signal to remind the user.

The leakage protection device 200 also has an over-temperature protection function. The thermistor T1 is provided at a specific position or on a specific element surface in the earth leakage protection device 200. The specific location may be, for example, a location on a PCB circuit board, within a housing near a plug blade, etc., and the specific element may be, for example, a solenoid SOL or other element in the circuit. When the leakage protection device 200 works normally, for example, overload or contact failure of a line does not occur, the temperature at a specific position and/or a specific element is low, the resistance value of the thermistor T1 is large, the current flows from the first current line 11-D2/D3-R6-T1-R10 to the ground, the upper voltage of the resistor R10 is low, and the trigger voltage of the trigger diode ZD1 is not reached, so that the trigger diode ZD1 is in a cut-off state. When the earth leakage protection device 200 fails, for example, the temperature at a specific location and/or a specific element increases due to an overload of a line or a poor contact of a plug, the resistance of the thermistor T1 decreases, and the upper voltage of the resistor R10 increases. Once the temperature at a specific location and/or at a specific element exceeds a preset threshold, the upper voltage of the resistor R10 rises to the trigger voltage of the trigger diode ZD1, that is, an over-temperature detection signal is provided to the trigger diode ZD1, the trigger diode ZD1 is triggered to be turned on, a current (over-temperature fault signal) flows through ZD1 and R13, and the trigger Q1 and/or Q2 is turned on, so that a current change is generated on the coil of the solenoid SOL, thereby generating an electromagnetic force, and the RESET switch RESET of the driving switch module 103 disconnects the power connection between the input terminal and the output terminal of the current-carrying line.

In addition, the earth leakage protection device 200 in fig. 2 may also perform a test of the earth leakage protection function. At the time of testing, the RESET switch RESET is closed. The TEST switch TEST of the monitoring module 108 is closed to form a current loop of the first current-carrying line 11-R1-the second current-carrying line 12, generating a simulated leakage current. The zero sequence current transformer ZCT1 detects the leakage current signal, generates a corresponding induction signal, and transmits the induction signal to the leakage detection chip U1. When the value of the leakage current is greater than the preset threshold, the pin 1 of the leakage detection chip U1 outputs a high level (leakage fault signal). The high level of pin 1 of the leakage detection chip U1 is provided to the control electrodes of the thyristors Q1 and Q2, triggering the thyristors Q1 and/or Q2 to conduct, thereby generating a current change in the coil of the solenoid SOL, and thus generating an electromagnetic force, driving the RESET switch RESET to open, and thereby disconnecting the power connection between the input terminal and the output terminal of the current line. If the RESET switch RESET is not opened, this indicates that the leakage protection function of the leakage protection device 200 is lost, and one or both of the leakage detection module 104 and the driving module 105 fail. By testing the leakage protection function through the monitoring module 108, a fault of the leakage protection device 200 can be found, and a user is reminded to replace the device in time.

Fig. 3 shows a schematic diagram of a second embodiment of the earth leakage protection device according to the present invention. Compared with the embodiment of fig. 2, the difference is mainly that a zener diode ZD3 is connected in parallel across the thermistor T1 and the resistor R10. The leakage protection function, the self-checking function, the testing function and the over-temperature protection function in this embodiment are the same as those in the embodiment of fig. 2, and will not be described here again.

In the embodiment of fig. 3, under the action of the zener diode ZD3, voltages at two ends of the thermistor T1 and the resistor R10 are kept stable, so as to reduce the influence of slight temperature variation of the resistance value of the resistor R6 or voltage variation of the input end of the current-carrying line, thereby improving the precision of the temperature preset threshold value and further improving the stability and safety of the over-temperature protection function of the electric leakage protection device 300.

Fig. 4 shows a schematic diagram of a third embodiment of the earth leakage protection device according to the present invention. The main difference compared to the embodiment of fig. 2 is that the trigger diode ZD1 is replaced with a transistor Q4 in the earth leakage protection device 400. The leakage protection function, the self-checking function and the testing function in this embodiment are the same as those in the embodiment of fig. 2, and will not be described here again.

When the leakage protection device 400 works normally, for example, overload or contact failure of the circuit is not occurred, the temperature at the specific position and/or the specific component is low, the resistance of the thermistor T1 is high, the current flows from the first current line 11-D2/D3-R5-T1-R10 to the ground, the voltage at the upper end of the resistor R10 is low, and the turn-on voltage of the transistor Q4 is not reached, so that the transistor Q4 is in the off state. When the earth leakage protection device 400 fails, for example, the temperature at a specific location and/or a specific element increases due to an overload of a line or a poor contact of a plug, the resistance of the thermistor T1 decreases, and the upper voltage of the resistor R10 increases. Once the temperature at the specific location and/or at the specific element exceeds a preset threshold, the upper voltage of the resistor R10 rises to the on voltage of the transistor Q4, that is, an over-temperature detection signal is provided to the transistor Q4, the transistor Q4 is turned on, a current (over-temperature fault signal) flows through Q4 and R13, triggering Q1 and/or Q2 to be turned on, so that a current change is generated on the coil of the solenoid SOL, and thus an electromagnetic force is generated, and the RESET switch RESET of the driving switch module 103 breaks the electrical connection between the input terminal and the output terminal of the current line.

Fig. 5 shows a schematic diagram of a fourth embodiment of the earth leakage protection device according to the present invention. The main difference compared to the embodiment of fig. 2 is that the over-temperature protection module 105 of the earth leakage protection device 500 is different. The leakage protection function, the self-checking function and the testing function in this embodiment are the same as those in the embodiment of fig. 2, and will not be described here again.

In the earth leakage protection device 500, the over-temperature protection module 105 mainly includes diodes D2 and D3 connected in parallel, a resistor R5, a thermistor T1, and a resistor R10 (first voltage dividing element) connected in series, R16 and R17 connected in series, and a comparator U2 (first voltage triggering sub-module). The upper end of R10 is connected to the non-inverting input end of the comparator U2, the upper end of R17 is connected to the inverting input end of the comparator U2, and the upper end voltage of R17 is used as the reference voltage of the comparator U2.

When the leakage protection device 500 works normally, for example, the circuit is not overloaded or the plug blade is not in contact with the fault, the temperature at the specific location and/or the specific component is low, the resistance of the thermistor T1 is high, the current flows from the first current line 11-D2/D3-R5-T1-R10 to the ground, the upper voltage of the resistor R10 is low and is lower than the upper voltage of the resistor R17 (i.e. the reference voltage), and therefore the comparator U2 outputs a low level. When the earth leakage protection device 500 fails, for example, the temperature at a specific location and/or a specific element increases due to an overload of a line or a poor contact of a plug, the resistance of the thermistor T1 decreases, and the upper voltage of the resistor R10 increases. Once the temperature at a specific location and/or at a specific element exceeds a preset threshold, the upper voltage of the resistor R10 rises to exceed a reference voltage, i.e. an over-temperature detection signal is provided to the comparator U2, the comparator U2 outputs a high level (over-temperature fault signal), triggering Q1 and/or Q2 to be turned on, and thus generating a current change on the coil of the solenoid SOL, thus generating an electromagnetic force, and the RESET switch RESET of the driving switch module 103 breaks the electrical connection between the input terminal and the output terminal of the current line.

Fig. 6 shows a schematic diagram of a fourth embodiment of the earth leakage protection device according to the present invention. In comparison with the embodiment of fig. 3, the difference is mainly that the leakage detection module 104 comprises two current transformers CT1 and CT2, wherein CT1 is used for ground fault detection of the second current line 12, and the full bridge rectifier DB is used for rectifying the power supply. Further, the drive module 106 includes two solenoids SOL1 and SOL2. The over-temperature protection function, the self-checking function and the testing function in this embodiment are the same as those in the embodiment of fig. 3, and will not be described here again.

In the normal operating state of the leakage protection device 500, when a leakage current exists on the first current carrying line 11 or the second current carrying line 12, the current transformer CT2 detects the leakage current signal, and the secondary side generates a corresponding induction signal, or when the second current carrying line 12 has a ground fault, the current transformer CT1 detects the ground fault, and the secondary side generates a corresponding induction signal. The current transformers CT1 and CT2 are coupled to the leakage detection chip U1, and the induction signals are transmitted to the leakage detection chip U1 for processing. When the processed value is greater than the set threshold, the pin 5 of the leakage detection chip U1 outputs a high level (leakage fault signal), and otherwise outputs a low level. The high level of pin 5 of the leakage detection chip U1 is supplied to the control electrodes of the thyristors Q1 and Q2 via the diode D2 and the resistor R6, triggering the thyristors Q1 and/or Q2 to conduct, thereby generating a current change on the coil of the solenoid SOL, and thus generating an electromagnetic force, and the RESET switch RESET of the driving switch module 103 disconnects the electrical connection between the input terminal and the output terminal of the current line, while the auxiliary switch SW disconnects.

Fig. 7 shows a schematic diagram of a fourth embodiment of the earth leakage protection device according to the present invention. The main difference compared to the embodiment of fig. 2 is that the over-temperature protection module 105 comprises diodes D2 and D3 connected in parallel, a resistor R6 connected in series and a bimetal switch T1.

When the earth leakage protection device 700 is operating normally, e.g. no overload of the line or no contact failure of the plug blades, the temperature at a specific location and/or at a specific element is low, the bimetal switch T1 is opened. When the earth leakage protection device 700 malfunctions, for example, due to an overload of a wire or a bad contact of a plug blade, etc., the temperature at a specific position and/or a specific element rises, the two metal pieces of the bimetal switch T1 start to bend and deform. Once the temperature at a specific location and/or at a specific element exceeds a preset threshold, the bimetal switch T1 is closed, and a current (an over-temperature fault signal) flows through R13, triggering Q1 and/or Q2 to be turned on, so that a current change is generated on the coil of the solenoid SOL, and thus an electromagnetic force is generated, and the RESET switch RESET of the driving switch module 103 breaks the electrical connection between the input terminal and the output terminal of the current-carrying line.

Fig. 8 shows a structural diagram of an electrical connection apparatus according to an embodiment of the present invention. Referring to fig. 8, the electrical connection apparatus 800 includes an upper case 81, a lower case 82, a power line 83, two plug blades 841 and 842, and a printed circuit board (PCB board, not shown in fig. 8). Various electronic components (such as those in the circuit structures shown in fig. 2 to 7) other than the thermistor are mounted on the PCB board. The power line 83 is electrically connected to the PCB board.

In fig. 8, the PCB board is covered by an upper case 81. The lower housing 82 is provided with apertures 821 and 822 corresponding to the positions of the plug blades 841 and 842, and when the upper and lower housings 81 and 82 are mounted together, the plug blades 841 and 842 pass through the corresponding apertures 821 and 822, respectively, and are exposed outside the lower housing 82 for insertion into a mating receptacle. In the vicinity of the apertures 821 and 822, a temperature sensing region 85 (i.e., a specific position) is further provided on the lower housing 82, and a thermistor 851 is installed in the temperature sensing region 85 to detect the temperature in the vicinity of the plug blades 841 and 842. The leakage protection device comprises a thermistor 851 and a PCB board, wherein two ends of the thermistor 851 are electrically connected with other electronic elements on the PCB board (such as circuit structures shown in fig. 2-7) so as to realize an over-temperature protection function.

Fig. 9 shows another structural diagram of an electrical connection apparatus according to an embodiment of the present invention. The electrical connection apparatus 900 includes an upper case 91, a lower case 92, a power cord 93, two plug blades 941 and 942, and a PCB board 95. Various electronic components (such as those in the circuit configuration shown in fig. 2-7) are mounted on the PCB board 95. The power line 93 is electrically connected to the PCB 95.

The main difference compared to the embodiment of fig. 8 is that in the embodiment of fig. 9, a thermistor 951 is mounted on the PCB board 95 at a position near the plug blades 941 and 942 (i.e., a specific position) to detect the temperature near the plug blades 941 and 942. The leakage protection device comprises a thermistor 951 and a PCB 95, wherein two ends of the thermistor 951 are electrically connected with other electronic elements on the PCB 95 (such as circuit structures shown in fig. 2-7) so as to realize an over-temperature protection function.

While fig. 8 and 9 illustrate that the thermistor may be mounted in the housing of the electrical connection device or on a PCB board, it will be appreciated that in other embodiments, other temperature sensors (e.g., diodes or bi-metal sheet switches) may be employed, as desired, and that the thermistor or other temperature sensor may be mounted at other specific locations or on a specific component surface.

A second aspect of the present invention proposes an electrical connection device comprising: a housing; and a leakage protection device according to any one of the above embodiments, the leakage protection device being accommodated in the housing.

A third aspect of the present invention proposes an electrical appliance comprising: a load device; and an electrical connection device coupled between the current carrying line and the load device for supplying power to the load device, the electrical connection device comprising the earth leakage protection device of any of the above embodiments.

Therefore, while the present invention has been described with reference to specific examples, which are intended to be illustrative only and not to be limiting of the invention, it will be apparent to those of ordinary skill in the art that changes, additions or deletions may be made to the disclosed embodiments without departing from the spirit and scope of the invention.

Claims

1. An earth leakage protection device comprising:

a switching module coupled between an input and an output of a current carrying line and configured to control a power connection between the input and the output;

a leakage detection module configured to detect a leakage current signal on the current carrying line and generate a leakage fault signal when the leakage current signal is detected;

an over-temperature protection module configured to detect a temperature of a specific location and/or a specific element in the earth leakage protection device and generate an over-temperature fault signal when the temperature is detected to exceed a preset threshold;

a drive module coupled to the switch module, the leakage detection module, and the over-temperature protection module and configured to receive the leakage fault signal and/or the over-temperature fault signal and drive the switch module to disconnect the power connection in response to the leakage fault signal and/or the over-temperature fault signal; and

a self-test module coupled to the leakage detection module and the drive module and configured to periodically generate the simulated leakage current signal to detect whether the leakage detection module and/or the drive module is malfunctioning and to generate a self-test fault signal when the leakage detection module and/or the drive module is malfunctioning.

2. The earth leakage protection device of claim 1, wherein the over-temperature protection module comprises at least one temperature sensor disposed at the particular location and/or the particular component surface.

3. The earth leakage protection device of claim 2, wherein the at least one temperature sensor comprises a thermistor, a diode, and/or a bi-metallic strip switch.

4. A leakage protection device according to claim 2 or 3, wherein the at least one temperature sensor comprises a thermistor, the over-temperature protection module comprising a first voltage trigger sub-module and at least one voltage dividing element connected in series with the thermistor and coupled to the first voltage trigger sub-module, the first voltage trigger sub-module further coupled to the drive module, wherein the at least one voltage dividing element provides an over-temperature detection signal to the first voltage trigger sub-module when the thermistor detects that the specific location and/or the temperature of the specific element exceeds the preset threshold, thereby causing the first voltage trigger module to generate the over-temperature fault signal.

5. The leakage protection device of claim 4, wherein the over-temperature protection module further comprises a voltage stabilizing element, the first voltage dividing element being connected in series with the thermistor and then connected in parallel with the voltage stabilizing element.

6. The earth leakage protection device of claim 4, wherein the first voltage trigger submodule includes a trigger diode, a transistor, a field effect transistor, and/or a comparator.

7. A leakage protection device according to claim 2 or 3, wherein the at least one temperature sensor comprises a bimetal switch coupled to the drive module, which is closed when the bimetal switch detects that the specific position and/or the temperature of the specific element exceeds the preset threshold, thereby generating the over-temperature fault signal.

8. The leakage protection device of claim 1, wherein the self-test module comprises a second voltage trigger sub-module and a first capacitor connected in series, and wherein the first capacitor is charged by the current carrying line and periodically generates the simulated leakage current signal via the second voltage trigger sub-module.

9. The leakage protection device of claim 8, wherein the second voltage trigger submodule includes a trigger diode, a transistor, a field effect transistor, and/or a comparator.

10. The earth leakage protection device of claim 1, further comprising:

a monitoring module is coupled to the leakage detection module and includes a test switch and is configured to generate the simulated leakage current signal when the test switch is operated to detect whether the leakage protection device is operating properly.

11. An electrical connection apparatus comprising:

a housing; and

the earth leakage protection device of any one of claims 1-10, the earth leakage protection device being housed in the housing.

12. An electrical appliance, comprising:

a load device; and

an electrical connection device coupled between a current carrying line and the load device for supplying power to the load device, wherein the electrical connection device comprises the earth leakage protection apparatus according to any one of claims 1-10.