CN215986424U

CN215986424U - Electric leakage detection device and charging equipment

Info

Publication number: CN215986424U
Application number: CN202121555448.1U
Authority: CN
Inventors: 杜明胜; 徐首旗
Original assignee: Shanghai Shengwei Electronic Technology Co ltd
Current assignee: Shanghai Shengwei Electronic Technology Co ltd
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2022-03-08
Anticipated expiration: 2031-07-08

Abstract

An electrical leakage detection device and a charging apparatus, the electrical leakage detection device comprising: the leakage current inductor is used for inducing a leakage current signal; the comparison circuit is connected with the leakage current inductor and used for comparing the leakage current signal with a preset threshold value and outputting a trigger signal when the leakage current signal is greater than or equal to the preset threshold value; the switching circuit is connected with the comparison circuit and used for switching from a first state to a second state when receiving the trigger signal; the switching circuit is connected with the first output interface and the second output interface, the first output interface outputs a first signal and the second output interface outputs a second signal when the switching circuit is in a first state, and the first output interface outputs the second signal and the second output interface outputs the first signal when the switching circuit is in a second state. If the first output interface and the second output interface are in a non-exclusive state, the device is indicated to have abnormality, and therefore the reliability of the leakage detection device is improved.

Description

Electric leakage detection device and charging equipment

Technical Field

The present invention relates generally to the field of leakage detection, and more particularly to a leakage detection device and a charging apparatus.

Background

An RCD (Residual Current Device) is an electric leakage detection Device for detecting the magnitude of an electric leakage Current in a line. If no RCD is installed in the circuit, when a person or an animal contacts high voltage, leakage current can be generated to the ground, and when the leakage current exceeds a certain threshold value, the heart of the person or the animal can vibrate, so that the heart stops suddenly, and further life danger is caused. If the leakage detection device such as the RCD is installed in the circuit, when leakage current exists in the circuit and the magnitude of a leakage current signal exceeds a set threshold value, the RCD can send an alarm signal to the action mechanism to trigger the action mechanism to quickly break the circuit, so that the purpose of protecting life safety is achieved.

The action mechanism is mainly used for breaking a circuit of the rear end power supply, and when the circuit is broken, the rear end of the breaker does not have voltage and current, so that the protection purpose is realized. The RCD board-mounted leakage module is widely applied to charging piles and charging guns at present, can be directly installed on a circuit board, and when an electric automobile is charged, the RCD is used for detecting whether leakage current exceeds a threshold value in the charging process, if the leakage current exceeds the threshold value, the RCD can send out an alarm signal to other devices in the circuit board to execute a command of stopping charging and disconnect a charging circuit, such as a closed relay or a circuit breaker mechanism.

At present, the RCD in a digital mode is used more and more, so that the product development is simpler, the period is shorter, and the research and development investment is less. However, the short development cycle does not mean that the reliability requirements can be reduced, and in particular that must be ensured for products such as earth leakage protection devices which involve personal safety protection.

SUMMERY OF THE UTILITY MODEL

In the summary section a series of concepts in a simplified form is introduced, which will be described in further detail in the detailed description section. The summary of the present application is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

An embodiment of the present invention provides a leakage detection apparatus, where the leakage detection apparatus includes a leakage current sensor and a control circuit connected to the leakage current sensor, the leakage current sensor is configured to sense a leakage current signal, and the control circuit includes:

the leakage current inductor is used for inducing a leakage current signal;

the comparison circuit is connected with the leakage current inductor and is used for comparing the leakage current signal with a preset threshold value and outputting a trigger signal when the leakage current signal is greater than or equal to the preset threshold value;

the switching circuit is connected with the comparison circuit and used for switching from a first state to a second state when receiving the trigger signal;

the switching circuit is connected with the switching circuit, the at least two output interfaces comprise a first output interface and a second output interface, when the switching circuit is arranged in a first state, the first output interface outputs a first signal, the second output interface outputs a second signal, when the switching circuit is arranged in a second state, the first output interface outputs a second signal, and the second output interface outputs the first signal.

In one embodiment, the at least two output interfaces include a plurality of sets of mutually exclusive output interfaces, and each set of the mutually exclusive output interfaces is a combination of the first output interface and the second output interface.

In one embodiment, the first signal is a low level signal and the second signal is a high level signal, or the first signal is a high level signal and the second signal is a low level signal.

In one embodiment, the first signal is a first pulse width modulated signal and the second signal is a second pulse width modulated signal.

In one embodiment, the first pulse width modulated signal and the second pulse width modulated signal have different duty cycles.

In one embodiment, the sum of the duty cycles of the first and second pulse width modulated signals is 100%.

In one embodiment, the apparatus further comprises a sampling resistor and an oscillation circuit disposed between the leakage current inductor and the control circuit.

In another aspect, the embodiment of the present invention provides a charging apparatus, where the charging apparatus includes the above leakage detection device, and an actuating mechanism connected to the leakage detection device, where the actuating mechanism is configured to disconnect a power supply line when the leakage detection device detects that a magnitude of a leakage current signal is greater than a preset threshold.

The leakage detection device and the charging equipment of the embodiment of the utility model adopt the two-way mutual exclusion interface, the first output interface and the second output interface are always in the mutual exclusion state under the normal working state, and if the first output interface and the second output interface are in the non-mutual exclusion state, the device is abnormal, so that the reliability of the leakage detection device is improved.

Drawings

The above and other objects, features and advantages of the present application will become more apparent by describing in more detail embodiments of the present application with reference to the attached drawings. The accompanying drawings are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings, like reference numbers generally represent like parts or steps.

Fig. 1 is a circuit diagram of a leakage detecting device according to an embodiment of the present invention.

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the utility model.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the utility model to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it can be directly on, adjacent to, connected or coupled to the other elements or layers or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to" or "directly coupled to" other elements or layers, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatial relational terms such as "under," "below," "under," "above," "over," and the like may be used herein for convenience in describing the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "under" and "under" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to provide a thorough understanding of the present invention, a detailed structure will be set forth in the following description in order to explain the present invention. The following detailed description of preferred embodiments of the utility model, however, the utility model is capable of other embodiments in addition to those detailed.

The Current RCD (Residual Current Device) has an analog form and also has a digital form; the Analog RCD directly outputs the waveform and amplitude of the leakage current, and if the controller of the client needs to know the waveform information and amplitude of the leakage current, the client must perform sampling calculation through its own ADC (Analog-to-Digital Converter) to determine, and then determine whether to perform a circuit breaking operation according to the calculation result, which increases the workload of the client and even has a relatively high risk of EMC (electromagnetic Compatibility).

For the digital RCD, after the leakage current value reaches the set threshold value, the digital high-low level signal (0 or 1) can be directly output, and the controller of the client can execute the responsive breaking action only by identifying the high-low level signal.

However, it has been found that, in the digital single-output RCD, although the function of the operation output pin is quite normal when the device is operating normally, when it is considered that some devices fail, the single-output RCD may have a condition that the output cannot jump, so that the complete machine of the client loses the leakage protection function, and an electric shock accident may occur.

Aiming at the problem, one solution is to design an output interface as open-drain output and connect a pull-up resistor externally, so that under the normal condition of no leakage, a master control chip always outputs high level to control the conduction of an MOS (metal oxide semiconductor) tube, and the output interface is low level; when electric leakage occurs, the output of the main control chip is changed from high to low, so that the MOS tube is not conducted, and the interface is pulled up to high level.

In the scheme, the main control chip outputs high level at ordinary times, so that the working state of the main control chip is verified to a certain extent. However, if the main control chip is halted or the output is high level when the program runs off, the MOS transistor is always in a conducting state, and the interface is always in low level, so that the back end cannot be notified by the level change when the leakage occurs. In addition, if the interface outputs a low level all the time due to a short circuit to the ground, it is also impossible to notify the back end of the leakage by a change in the level. That is, this scheme does not completely prevent the RCD from not operating when a leakage occurs due to an interface abnormality.

In view of the above problems, an embodiment of the present invention provides a leakage detection device and a charging apparatus, where a dual-channel mutual exclusion interface is adopted in the leakage detection device, and in a normal operating state, a first output interface and a second output interface are always in a mutual exclusion state, and if the first output interface and the second output interface are in a non-mutual exclusion state, it indicates that the leakage detection device is abnormal, so as to improve reliability of the leakage detection device.

The following describes the leakage detecting device and the charging device in detail according to the embodiment of the present invention with reference to the drawings. The features of the following examples and embodiments may be combined with each other without conflict.

Referring to fig. 1, the leakage detection apparatus according to the embodiment of the present invention at least includes a leakage current sensor 101 and a control circuit 102 connected to the leakage current sensor 101, where the leakage current sensor 101 is configured to sense a leakage current signal 102, and the control circuit 102 includes:

the comparison circuit is connected with the leakage current inductor 101 and used for comparing the leakage current signal with a preset threshold value and outputting a trigger signal when the leakage current signal is greater than or equal to the preset threshold value; the switching circuit is connected with the comparison circuit and used for switching from a first state to a second state when receiving the trigger signal; and the at least two output interfaces are connected with the switching circuit, the at least two output interfaces comprise a first output interface 103 and a second output interface 104, when the switching circuit is arranged in a first state, the first output interface 103 outputs a first signal, the second output interface 104 outputs a second signal, when the switching circuit is arranged in a second state, the first output interface 103 outputs the second signal, and the second output interface 104 outputs the first signal.

The leakage detection device of the embodiment of the utility model is a digital leakage detection device, which adopts two mutually exclusive output interfaces, that is, the outputs of the first output interface 103 and the second output interface 104 are always in opposite states, when no leakage occurs, the first output interface 103 always outputs a first signal, the second output interface 104 always outputs a second signal, when leakage occurs, the first output interface 103 outputs the second signal, the second output interface 104 outputs the first signal, but whether leakage occurs or not, the first output interface 103 and the second output interface 104 are both kept in mutually exclusive states. If the outputs of the first output interface 103 and the second output interface 104 are in a non-exclusive state, it indicates that the leakage detection device is abnormal, for example, the interface is abnormal or the main control chip is abnormal, so as to ensure that when the device is abnormal, the client can timely determine the abnormality and timely replace the leakage detection device with normal function, and also ensure that when the main control chip is halted or the program is run away, the client can timely determine the abnormality and timely reset the system.

The leakage detection device of the embodiment of the present invention may use a fluxgate technology, and the leakage Current inductor 101 may use a ZCT (Zero Current Transformer). Referring to fig. 1, a primary side three-phase wire of the zero sequence current transformer passes through an iron core, and a secondary coil is wound on the iron core. Under normal conditions, three-phase currents on the primary side of the zero-sequence current transformer are symmetrical, and the vector sum is zero. When the system has single-phase earth fault, the sum of three-phase currents is not zero, zero-sequence magnetic flux occurs in the iron core, the magnetic flux induces potential on the secondary coil, and secondary current is generated.

Furthermore, the leakage detection device according to the embodiment of the present invention may be a B-type leakage detection device, which is capable of detecting both ac leakage and pulsating DC leakage, and also has the capability of detecting 2P-DC (two-phase rectification), 3P-DC (three-phase rectification), S-DC (smooth DC), and F-type (10Hz, 50Hz, 1000Hz) complex waves.

Specifically, in the B-type leakage detecting device, a sampling resistor 105 is further included between the leakage current sensor 101 and the control circuit 102, and the control circuit 102 obtains a leakage current signal through the sampling resistor 105. And, also include the oscillating circuit (OSC) set up between leakage current inductor 101 and control circuit 102, the control circuit 102 applies the excitation current to the zero sequence current transformer through the oscillating circuit, in order to drive the ZCT coil, make its magnetic core magnetize, meanwhile, the control circuit 102 can obtain the waveform signal voltage information including excitation voltage waveform through detecting the voltage on the sampling resistor 105, the voltage information includes the information of the magnetic flux of the zero sequence too; the zero sequence magnetic flux information can be obtained by filtering the excitation waveform information through the filter, and the zero sequence magnetic flux is generated by the leakage current, so that the leakage current information can be obtained, and the function of detecting the alternating current leakage current and the direct current leakage current is realized.

Further, the leakage detecting device may adopt an open-loop or closed-loop excitation method. The excitation frequency in the open-loop excitation mode is generated by an oscillation circuit, the oscillation frequency is comprehensively determined according to the characteristics of different transformers and the magnitude of a driving current signal, and once the excitation frequency is determined, the excitation frequency is fixed and cannot be randomly modified in the application process. In the closed loop type excitation mode, the excitation frequency is related to characteristic parameters such as the number of turns, Bm, coil excitation voltage, sectional area Ac and the like of the ZCT transformer, a feedback signal is generated by comparing the voltage generated on the sampling resistor 105 with the voltage configured in advance by the comparator, the feedback signal is fed back to the excitation circuit in the control circuit 102, the frequency of the excitation current is adjusted until the circuit is in a stable state, and the excitation frequency also tends to be stable at the moment.

It should be noted that the leakage current detector used in the embodiment of the present invention is not limited to the ZCT using the magnetic modulation technique, and for example, the leakage current detector may also use a hall method or any other suitable method to implement the leakage current sensing function.

The leakage current sensor 101 is connected to the control circuit 102, and the control circuit 102 may be implemented as an MCU (micro control unit) or other control unit or circuit with similar functions. The control circuit 102 comprises a comparison circuit, a switching circuit and at least two output interfaces, wherein the output interfaces comprise at least a first output interface 103 and a second output interface 104 which are mutually exclusive. When the leakage current signal is greater than or equal to the preset threshold value, the comparison circuit outputs a trigger signal, and the switching circuit is switched from the first state to the second state. When the switching circuit is set in the first state, the first output interface 103 outputs a first signal, and the second output interface 104 outputs a second signal, and when the switching circuit is set in the second state, the first output interface 103 outputs the second signal, and the second output interface 104 outputs the first signal. According to the output signals of the first output interface 103 and the second output interface 104, the client can judge whether the leakage detection device has an abnormality or not, and can judge whether the leakage detection device has an abnormality or not.

In one embodiment, the first signal and the second signal are high-low level signals, that is, the first signal is a low level signal and the second signal is a high level signal, or the first signal is a high level signal and the second signal is a low level signal. In a normal state, the first output interface 103 outputs a low level signal, the second output interface 104 outputs a high level signal, and during the leakage protection operation, the output signal of the first output interface 103 changes from a low level signal to a high level signal, and the output signal of the second output interface 104 changes from a high level signal to a low level signal. Namely, when the leakage detection device works normally, the outputs of the two output interfaces always present mutually exclusive states.

In this embodiment, the switching circuit may include a first MOS transistor and a second MOS transistor, which are respectively connected to the first output interface 103 and the second output interface 104, and in a normal case where no leakage occurs, the first MOS transistor is turned on, the first output interface 103 outputs a low level signal, the second MOS transistor is turned off, and the second output interface 104 outputs a high level signal; when leakage occurs, the first MOS transistor is not turned on, the first output interface 103 outputs a high level signal, the second output interface 104 is turned on, and the second output interface outputs a low level signal.

The first signal and the second signal may be other types of mutually exclusive signals besides the high-low level signal. For example, the first signal and the second signal may be PWM (pulse width modulation) signals, that is, the first signal is a first pulse width modulation signal, the second signal is a second pulse width modulation signal, and the switching circuit includes two analog-to-digital conversion circuits for outputting different pulse width modulation signals. Wherein the first and second pulse width modulated signals have different signal characteristics, e.g., the first and second pulse width modulated signals have different duty cycles. Illustratively, the mutually exclusive form of the first pulse width modulation signal and the second pulse width modulation signal is that the sum of duty ratios of the first pulse width modulation signal and the second pulse width modulation signal is 100%, for example, the duty ratio of the first pulse width modulation signal is 60%, the duty ratio of the second pulse width modulation signal is 40%, when no leakage occurs, the first output interface 103 outputs one PWM signal with a duty ratio of 60%, and the second output interface 104 outputs one PWM signal with a duty ratio of 40%; when electric leakage occurs, the first output interface 103 outputs a PWM signal with a duty ratio of 40%, and the second output interface 104 outputs a PWM signal with a duty ratio of 60%, that is, the sum of the duty ratios of the two signals is always 100%, so as to determine whether the electric leakage detection device works normally.

In an embodiment, the at least two output interfaces include a plurality of sets of mutually exclusive output interfaces, and each set of mutually exclusive output interfaces is a combination of the first output interface and the second output interface, that is, two mutually exclusive output interfaces are mutually exclusive, so as to further improve the reliability of the apparatus. The signal types output by the mutually exclusive output interfaces of different groups can be the same or different. For example, each set of mutually exclusive output interfaces respectively outputs a high level signal or a low level signal. Or at least one group of the mutually exclusive output interfaces respectively outputs high-level signals and low-level signals, and the other at least one group of the mutually exclusive output interfaces respectively outputs pulse width modulation signals with different duty ratios.

Illustratively, the control circuit 102 may further include a power VCC interface, a GND interface, and the like, in addition to the first output interface 103 and the second output interface 104, which are not described in detail herein.

Based on the above description, the leakage detection device according to the embodiment of the present invention employs two mutually exclusive interfaces, the first output interface and the second output interface are always in a mutually exclusive state in a normal operating state, and if the first output interface and the second output interface are in a non-mutually exclusive state, it indicates that the device is abnormal, thereby improving the reliability of the leakage detection device.

The embodiment of the utility model also provides charging equipment which comprises the leakage detection device and an action mechanism connected with the leakage detection device, wherein the action mechanism is used for disconnecting the power supply circuit when the leakage detection device detects that the magnitude of the leakage current signal is greater than a preset threshold value. The charging equipment provided by the embodiment of the utility model can be realized as charging equipment for charging vehicles, such as a charging pile, a charging gun and the like, the electric leakage detection device can be a board-mounted electric leakage detection device which can be directly mounted on a PCB (printed circuit board) of the charging equipment, when the charging equipment charges an electric automobile, the electric leakage detection device can be used for detecting whether the magnitude of the electric leakage current exceeds a threshold value in the charging process, and when the magnitude of the electric leakage current exceeds the threshold value, an alarm is sent to an MCU (microprogrammed control unit) or other devices on the PCB so as to execute a charging stopping command and disconnect a charging circuit, such as a closed relay or a circuit breaker mechanism and the like.

The charging equipment comprises the leakage detection device, and the leakage detection device has high reliability, so that the safety of the charging equipment is ensured.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the utility model may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the description of exemplary embodiments of the utility model, various features of the utility model are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present invention should not be construed to reflect the intent: that the utility model as claimed requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the utility model and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.

It should be noted that the above-mentioned embodiments illustrate rather than limit the utility model, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The utility model may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

The above description is only for the specific embodiment of the present invention or the description thereof, and the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein should be covered within the protection scope of the present invention. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An electrical leakage detection device, comprising a leakage current sensor and a control circuit connected to the leakage current sensor, wherein the leakage current sensor is configured to sense a leakage current signal, and wherein the control circuit comprises:

2. The leakage detection device according to claim 1, wherein the at least two output interfaces include a plurality of sets of mutually exclusive output interfaces, each set of mutually exclusive output interfaces being a combination of the first output interface and the second output interface.

3. The electrical leakage detection device of claim 1, wherein the first signal is a low level signal and the second signal is a high level signal, or wherein the first signal is a high level signal and the second signal is a low level signal.

4. The electrical leakage detection device of claim 1, wherein the first signal is a first pulse width modulated signal and the second signal is a second pulse width modulated signal.

5. The leakage detection device of claim 4, wherein the first pulse width modulated signal and the second pulse width modulated signal have different duty cycles.

6. The leakage detection device of claim 5 wherein the sum of the duty cycles of the first pulse width modulated signal and the second pulse width modulated signal is 100%.

7. The electrical leakage detection device according to claim 1, further comprising a sampling resistor and an oscillation circuit provided between the leakage current sensor and the control circuit.

8. A charging apparatus, characterized in that the charging apparatus comprises:

the electrical leakage detection device according to any one of claims 1 to 7;

and the action mechanism is connected with the electric leakage detection device and is used for disconnecting the power supply circuit when the electric leakage detection device detects that the magnitude of the electric leakage current signal is greater than a preset threshold value.