Leakage protection device

Abstract

The present invention discloses a leakage protection device, which includes a leakage detection unit; a switch module; a first driving unit including a first transistor and a reset module; a reset switch; a delay trigger unit coupled to an input end of a power supply line, the first driving unit, and the reset switch, and configured to turn on the first transistor of the first driving unit after a predetermined time when the input end of the leakage protection device is powered on or the reset switch resets the main circuit, so as to turn on the switch module to establish a power connection; and a second driving unit including a second transistor and a tripping module, the second transistor being coupled to the tripping module, the second driving unit being configured to drive the second transistor to turn on in response to the leakage detection unit detecting a leakage fault signal, so as to turn off the switch module to disconnect the power connection. The present invention can avoid frequent power-on of the solenoid coil, which may cause serious heating of the coil and pose a safety hazard, thereby protecting the leakage protection device.

Description

Technical Field

[0001] The present invention relates to the electrical field, and particularly to a leakage protection device. Background Art

[0002] Some existing automatic reset type leakage protection devices are prone to frequently automatically driving the coil to be powered on when the input voltage is unstable, when manual reset and power-on operations are repeatedly performed, or when the external environment is relatively complex. As a result, the coil gets severely heated or even burned out, and then the device loses its leakage protection function, creating a safety hazard. Summary of the Invention

[0003] Based on the above problems, the present invention provides a leakage protection device, including a leakage detection unit for detecting whether there is a leakage fault signal at the load end of the power supply line; a switch module for controlling the electrical connection between the input end and the load end of the power supply line; a first driving unit including a first transistor and a reset module, the first transistor being coupled to the reset module; a reset switch; a delay trigger unit coupled to the input end of the power supply line, the first driving unit, and the reset switch, the delay trigger unit being configured to make the first transistor of the first driving unit conduct electricity after a predetermined time when the input end of the leakage protection device is powered on or the reset switch resets the main circuit, so that the reset module is powered on, and then the switch module connects the electrical connection; and a second driving unit including a second transistor and a tripping module, the second transistor being coupled to the tripping module, the second driving unit being configured to drive the second transistor to conduct electricity in response to the leakage detection unit detecting the existence of the leakage fault signal, so that the tripping module is powered on, and then the switch module disconnects the electrical connection.

[0004] In one embodiment, the delay trigger unit includes a rectifying unit, a first resistor, a first capacitor, a second capacitor, a third transistor, and a fourth transistor. A first end of the rectifying unit is coupled to a first input terminal among the input terminals of the power supply line, and a second end of the rectifying unit is coupled to a first end of the first resistor. A second end of the first resistor is coupled to a first end of the first capacitor, and a second end of the first capacitor is coupled to a second input terminal among the input terminals of the power supply line. The second end of the first resistor is further coupled to a first end of the second capacitor. A first pole of the first transistor is coupled to the reset module, and a second pole and a third pole of the first transistor are respectively coupled to a second end of the second capacitor and a second end of the first capacitor. A first pole and a second pole of the third transistor are coupled to a first end of the first capacitor, and a third pole of the third transistor is coupled to a second end of the first capacitor. A first pole and a second pole of the fourth transistor are respectively coupled to a first end of the second capacitor and a first pole of the third transistor, and a third pole of the fourth transistor is coupled to a second end of the first capacitor. The reset switch is coupled across the two ends of the first capacitor.

[0005] In one embodiment, the delay trigger unit includes a rectifying unit, a first resistor, a first capacitor, a second capacitor, and a third transistor. A first end of the rectifying unit is coupled to a first input terminal among the input terminals of the power supply line, and a second end of the rectifying unit is coupled to a first end of the first resistor. A second end of the first resistor is coupled to a first end of the first capacitor. A first pole and a second pole of the third transistor are coupled to a first end of the first capacitor, and a third pole of the third transistor is coupled to a first end of the second capacitor. A first pole and a second pole of the first transistor are respectively coupled to the reset module and a second end of the second capacitor, and a third pole of the first transistor is coupled to a second end of the first capacitor. A second end of the first capacitor is coupled to a second input terminal among the input terminals of the power supply line. The reset switch is coupled across the two ends of the first capacitor.

[0006] In one embodiment, the rectifying unit is a diode.

[0007] In one embodiment, the rectifying unit is a full-bridge rectifier circuit. An input terminal of the full-bridge rectifier circuit is coupled to the input terminal of the power supply line, and an output terminal of the full-bridge rectifier circuit is coupled to a first end of the first resistor and a second end of the first capacitor.

[0008] In one embodiment, it further includes a ground fault detection unit, which is coupled to the second driving unit. The second driving unit is further configured to drive the second transistor to conduct in response to the ground fault detection unit detecting a ground fault signal, so that the trip module is powered on, and then the switch module disconnects the power connection.

[0009] In one embodiment, the first transistor, the second transistor, the third transistor, and the fourth transistor can be MOS transistors, thyristors, triodes, or other controllable switch devices.

[0010] In one embodiment, the reset module and the trip module are solenoids or other electromagnetic devices.

[0011] By implementing the technical solution of the present invention, it is possible to avoid frequent power-on of the solenoid coil, which may cause serious heating of the coil and pose a safety hazard, thereby protecting the leakage protection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The embodiments are illustrated and clarified with reference to the accompanying drawings. These drawings are used to clarify the basic principles and thus only show the aspects necessary for understanding the basic principles. These drawings are not to scale. In the drawings, the same reference numerals represent similar features.

[0013] Figure 1 is a schematic circuit structure diagram of a leakage protection device according to the first embodiment of the present invention;

[0014] Figure 2 is a schematic circuit structure diagram of a leakage protection device according to the second embodiment of the present invention;

[0015] Figure 3 Schematic circuit structure diagram of a leakage protection device according to the third embodiment of the present invention;

[0016] Figure 4 Schematic circuit structure diagram of a leakage protection device according to the fourth embodiment of the present invention;

[0017] Figure 5 Schematic circuit structure diagram of a leakage protection device according to the fifth embodiment of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In the following detailed description of the preferred embodiments, reference will be made to the accompanying drawings that form a part of the present invention. The accompanying drawings illustrate, by way of example, specific embodiments capable of implementing the present invention. The example embodiments are not intended to exhaust all embodiments according to the present invention. It will be understood that other embodiments may be utilized and structural or logical modifications may be made without departing from the scope of the present invention. Accordingly, the following detailed description is not restrictive, and the scope of the present invention is defined by the appended claims.

[0019] As used herein, the terms "comprising", "including" and similar terms should be understood as open-ended terms, i.e., "including / including but not limited to", indicating that other elements may also be included. The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment" and so on.

[0020] The following will be combined with Figures 1 to 5 to describe in detail the working principle of the leakage protection device of the present invention.

[0021] Figure 1 is a schematic circuit diagram of a leakage protection device according to a first embodiment of the present invention. As Figure 1 shown, the leakage protection device includes a switch module 10, a delay trigger unit 11, a first drive unit 12, a reset switch 14, a leakage detection unit 21, and a second drive unit 22. The leakage detection unit 21 is configured to detect whether there is a leakage fault signal at the load end of the power supply line. The switch module 10 is configured to control the power connection between the input end (i.e., the power input end) and the load end of the power supply line. The first drive unit 12 includes a first transistor and a reset module, and the first transistor is coupled to the reset module. The delay trigger unit 11 is coupled to the input end of the power supply line, the first drive unit 12, and the reset switch 14. The delay trigger unit 11 is configured to, after the input end of the leakage protection device is powered on or the reset switch 14 resets the main circuit, after a predetermined time (for example, 2-3 seconds), turn on the first transistor of the first drive unit 12, thereby turning on the reset module, and further turning on the switch module 10 to connect the power connection between the input end and the load end of the power supply line. The second drive unit 22 includes a second transistor and a trip module, and the second transistor is coupled to the trip module. The trip module is configured to drive the second transistor to turn on in response to the leakage detection unit 21 detecting a leakage fault signal at the load end of the power supply line, thereby energizing the trip module, and further turning off the switch module 10 to disconnect the power connection between the input end and the load end of the power supply line.

[0022] Specifically, as Figure 1As shown, the delay trigger unit 11 includes a diode D1 (i.e., a rectification unit), a resistor R2 (i.e., a first resistor), a capacitor C4 (i.e., a first capacitor), a thyristor Q4 (i.e., a third transistor), a triode Q3 (i.e., a fourth transistor), and a capacitor C2 (i.e., a second capacitor). The first drive unit 12 includes a thyristor Q1 (i.e., a first transistor) and a solenoid SOL1 (i.e., a reset module). SOL1 is coupled to the switch module 10. The first end of the diode D1 is connected to the first power supply line (i.e., the first input terminal among the input terminals of the power supply line), the second end of the diode D1 is connected to the first end of the resistor R2, the second end of the resistor R2 is connected to the first end of the capacitor C4, the second end of the capacitor C4 is grounded (since the second power supply line (i.e., the second input terminal among the input terminals of the power supply line) is also grounded, which is equivalent to the second end of C4 being connected to the second power supply line), the second end of the resistor R2 is coupled to the first end of the capacitor C2 and is also coupled to the anode (i.e., the first pole) and the gate (i.e., the second pole) of the thyristor Q4. The cathode (i.e., the third pole) of the thyristor Q4 is coupled to the second end of the capacitor C4, the second end of the capacitor C2 is coupled to the gate (i.e., the second pole) of the thyristor Q1, the anode (i.e., the first pole) of the thyristor Q1 is coupled to the solenoid SOL1, the cathode (i.e., the third pole) of the thyristor Q1 is coupled to the second end of the capacitor C4, the collector (i.e., the first pole) and the base (i.e., the second pole) of the triode Q3 are respectively coupled to the first end of the capacitor C2 and the anode of the thyristor Q4, and the emitter (i.e., the third pole) of the triode Q3 is coupled to the second end of the capacitor C4. The leakage detection unit 21 includes a leakage detection coil CT1 and a processor U1. The leakage detection coil CT1 is coupled to the processor U1. The cathode (i.e., the third pole) and the gate (i.e., the second pole) of the thyristor Q2 (i.e., a second transistor) are coupled to the processor U1, and the anode (i.e., the first pole) of the thyristor Q2 is coupled to a solenoid SOL2 (i.e., a trip module). SOL2 is coupled to the switch module 10. It should be understood that in one embodiment, the first power supply line is the L line and the second power supply line is the N line; in another embodiment, the first power supply line is the N line and the second power supply line is the L line.

[0023] Figure 1 The working principle of the leakage protection device in

[0024] The current of the main circuit is rectified by D1 and then charges capacitor C4 through R2. After the first period of time, the voltage at the upper end (i.e., the first terminal) of C4 rises to make Q3 conduct, discharging the charge in C2 and putting Q1 in the cut-off state. The voltage at the upper end of C4 continues to rise. After the second period of time, the voltage at the upper end of C4 rises high enough so that after being divided by R6 and R9, the voltage at the upper end of R9 can trigger Q4 to conduct. After Q4 conducts, Q3 cuts off. Then Q4 maintains the conducting state, and the current charges C2 through D1 - R2 - R3, making Q1 conduct, and further making the current pass through SOL1, thereby driving the switch module 10 of the leakage protection device to close to connect the power connection between the input end and the load end of the power supply line. When C2 is fully charged, Q1 cuts off. After the leakage protection device trips due to a fault and disconnects the switch module 10 (for example, when the leakage detection coil CT1 detects a leakage current between the input end and the load end of the power supply line (i.e., there is a leakage fault signal), the processor U1 issues a driving signal to drive the thyristor Q2 to conduct, making SOL2 energized, thereby disconnecting the switch module 10), the charge in C4 is released by pressing the reset switch 14, thus repeating the above process of driving the switch module 10 to close. Figure 1 The implementation method of the first embodiment shown can extend the time for the switch module to form a closed state after the input end of the leakage protection device is powered on or the reset switch is reset (for example, extend the predetermined time composed of the first time and the second time (for example, 2 - 3 seconds). It should be understood that the length of the predetermined time can be adjusted by setting R2 and C4), thereby avoiding the solenoid coil from being frequently powered on, which may cause serious heating of the coil and pose a safety hazard, thus protecting the leakage protection device.

[0025] As Figure 2 shown, the circuit structure of the leakage protection device of the second embodiment is similar to Figure 1 the circuit structure of the leakage protection device of the first embodiment shown. The difference is that Figure 1 the thyristor Q4 in

[0026] Figure 2 is replaced by a triode Q4. Figure 1 The working principle of the leakage protection device in

[0027] Figure 3 is similar to the working principle of the leakage protection device in Figure 1 shown, and will not be elaborated here. Figure 3The delay trigger unit 130 of the leakage protection device in the third embodiment further includes voltage-dividing resistors R8, R12, and a voltage-regulating diode ZD1. After the resistors R8, R12, and R5 divide the voltage together, Q3 is prompted to conduct. The voltage-regulating diode ZD1 further reduces the voltage after R6 and R9 complete the voltage reduction to trigger Q4 to conduct. In addition, Figure 3 The leakage protection device in the third embodiment further includes a ground fault detection unit, and the ground fault detection unit includes a ground fault detection coil CT2.

[0028] Figure 3 The working principle of the leakage protection device is as follows:

[0029] The current of the main circuit is rectified by D1 and then charges the capacitor C4 through R2. After a first period of time, the voltage at the upper end (i.e., the first terminal) of C4 is divided by R5, R8, and R12 to prompt Q3 to conduct, releasing the electric charge in C2, so that Q1 is in the cut-off state. After that, the voltage at the upper end of C4 continues to rise. After a second period of time, the voltage at the upper end of C4 rises to a level sufficient to trigger Q4 to conduct after being divided by R6 and R9 and further reduced by ZD1. After Q4 conducts, Q3 cuts off, and Q4 maintains the conducting state. The current charges C2 through D1 - R2 - R3, making Q1 conduct, so that SOL1 is energized, driving the switch module 10 of the leakage protection device to close. When C2 is fully charged, the thyristor Q1 cuts off. Similar to Figure 1 the embodiment shown in

[0030] Figure 4 When the leakage protection device trips due to a fault and disconnects the switch module 10 (for example, when the leakage detection coil CT1 detects a leakage current between the input end and the load end of the power supply line (i.e., there is a leakage fault signal) or the ground fault detection coil CT2 detects a ground fault signal, the processor U1 issues a driving signal to drive the thyristor Q2 to conduct, making SOL2 energized, thereby disconnecting the switch module 10). After that, the electric charge in C4 is released by pressing the reset switch 14, and then the above process of driving the switch module 10 to close is repeated. Figure 1 the circuit structure of the first embodiment shown in Figure 4 the delay trigger unit 140 of

[0031] Figure 4 The working principle of the leakage protection device is as follows:

[0032] The main circuit current is rectified by D1 and then charges the capacitor C4 through R2. After a first period of time, the voltage at the upper end (i.e., the first terminal) of C4 rises high enough so that after the voltage division by R6 and R9, the voltage at the upper end of R9 can trigger Q4 to conduct. After Q4 conducts, the current charges C2 through D1 - R2 - R3 - Q4, causing Q1 to conduct, and then SOL1 is powered on, thereby closing the switch module 10 of the leakage protection device. When C2 is fully charged, the thyristor Q1 is turned off. When the leakage protection device trips due to a fault and the switch module 10 is disconnected (for example, when the leakage detection coil CT1 detects a leakage current between the input end and the load end of the power supply line (i.e., there is a leakage fault signal), it drives the thyristor Q2 to conduct through the processor U1, causing SOL2 to be powered on, and thus the switch module 10 is disconnected), the power in C4 is released by pressing the reset switch 14, thereby repeating the process of driving the switch module 10 to close as described above.

[0033] Figure 5 The circuit structure of the leakage protection device of the fifth embodiment shown is similar to Figure 1 the circuit structure of the leakage protection device of the first embodiment shown. The difference is that Figure 5 the leakage protection device uses a full - bridge circuit DB instead of Figure 1 the diode D1 in to perform rectification. The input end of the full - bridge circuit DB is coupled to the input end of the power supply line, and the output end of the full - bridge circuit DB is coupled to the resistor R2 and the second terminal of the capacitor C4 and the first terminal.

[0034] Figure 5 The working principle of the leakage protection device of Figure 1 the leakage protection device shown is the same as that shown and will not be elaborated here.

[0035] It should be understood that the first transistor, the second transistor, the third transistor, and the fourth transistor herein can all be MOS transistors, triodes, thyristors, or other controllable switch devices. It should also be understood that Figures 1 to 4 the rectification units in can all be either full - bridge circuits or diodes, or other suitable units that play a rectification role. It should also be understood that the reset module and the tripping module can be other electromagnetic devices besides solenoids.

[0036] Therefore, although the present invention is described with reference to specific examples, and these specific examples are only intended to be exemplary and not to limit the present invention, it is obvious to those of ordinary skill in the art that changes, additions, or deletions can be made to the disclosed embodiments without departing from the spirit and scope of the present invention.

Claims

1. A leakage protection device, further characterized in that, including a leakage detection unit configured to detect whether there is a leakage fault signal at a load end of a power supply line; a switch module configured to control a power connection between an input end and the load end of the power supply line; a first driving unit including a first transistor and a reset module, the first transistor being coupled to the reset module; a reset switch; a delay trigger unit coupled to the input end of the power supply line, the first driving unit, and the reset switch, the delay trigger unit being configured to turn on the first transistor of the first driving unit after a predetermined time when power is applied to an input end of the leakage protection device or the reset switch resets a main circuit, so that the reset module is powered on, and further so that the switch module connects the power connection; and a second driving unit including a second transistor and a trip module, the second transistor being coupled to the trip module, the second driving unit being configured to drive the second transistor to turn on in response to the leakage detection unit detecting the leakage fault signal, so that the trip module is powered on, and further so that the switch module disconnects the power connection.

2. The leakage protection device according to claim 1, characterized in that, The delay trigger unit includes a rectifying unit, a first resistor, a first capacitor, a second capacitor, a third transistor, and a fourth transistor. A first end of the rectifying unit is coupled to a first input end of the input end of the power supply line and a second end of the rectifying unit is coupled to a first end of the first resistor. A second end of the first resistor is coupled to a first end of the first capacitor and a second end of the first capacitor is coupled to a second input end of the input end of the power supply line. The second end of the first resistor is further coupled to a first end of the second capacitor. A first pole of the first transistor is coupled to the reset module. A second pole and a third pole of the first transistor are respectively coupled to a second end of the second capacitor and a second end of the first capacitor. A first pole and a second pole of the third transistor are coupled to the first end of the first capacitor. A third pole of the third transistor is coupled to a second end of the first capacitor. A first pole and a second pole of the fourth transistor are respectively coupled to the first end of the second capacitor and a first pole of the third transistor. A third pole of the fourth transistor is coupled to a second end of the first capacitor. The reset switch is coupled across the first capacitor.

3. The leakage protection device according to claim 1, characterized in that The delay trigger unit includes a rectification unit, a first resistor, a first capacitor, a second capacitor, and a third transistor. A first end of the rectification unit is coupled to a first input terminal among the input terminals of the power supply line, and a second end of the rectification unit is coupled to a first end of the first resistor. A second end of the first resistor is coupled to a first end of the first capacitor. A first pole and a second pole of the third transistor are coupled to the first end of the first capacitor, and a third pole of the third transistor is coupled to a first end of the second capacitor. A first pole and a second pole of the first transistor are respectively coupled to the reset module and a second end of the second capacitor, and a third pole of the first transistor is coupled to a second end of the first capacitor. The second end of the first capacitor is coupled to a second input terminal among the input terminals of the power supply line. The reset switch is coupled across the two ends of the first capacitor.

4. The leakage protection device according to claim 2 or 3, characterized in that, The rectification unit is a diode.

5. The leakage protection device according to claim 2 or 3, characterized in that, The rectification unit is a full-bridge rectifier circuit. An input terminal of the full-bridge rectifier circuit is coupled to the input terminals of the power supply line, and an output terminal of the full-bridge rectifier circuit is coupled to the first end of the first resistor and the second end of the first capacitor.

6. The leakage protection device according to claim 1 further includes a ground fault detection unit. The ground fault detection unit is coupled to the second driving unit. The second driving unit is further configured to drive the second transistor to conduct in response to the ground fault detection unit detecting a ground fault signal, so that the trip module is powered on, and further so that the switch module disconnects the power connection.

7. The leakage protection device according to claim 2, characterized in that, The first transistor, the second transistor, the third transistor, and the fourth transistor can be MOS transistors, thyristors, triodes, or other controllable switch devices.

8. The leakage protection device according to claim 1, characterized in that, The reset module and the trip module are solenoids or other electromagnetic devices.

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