CN113296019A - Electric leakage detection device, electric leakage detection method and charging equipment - Google Patents
Electric leakage detection device, electric leakage detection method and charging equipment Download PDFInfo
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- CN113296019A CN113296019A CN202110501017.5A CN202110501017A CN113296019A CN 113296019 A CN113296019 A CN 113296019A CN 202110501017 A CN202110501017 A CN 202110501017A CN 113296019 A CN113296019 A CN 113296019A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
Abstract
An electric leakage detection device, an electric leakage detection method, and a charging apparatus, the electric leakage detection device comprising: the leakage current inductor is used for inducing a leakage current signal; control circuit, connect the leakage current inductor, control circuit includes: the comparison circuit is connected with the leakage current inductor and is used for comparing the leakage current signal with a corresponding preset threshold value; the analog-to-digital conversion circuits are connected with the comparison circuits in a one-to-one correspondence mode and used for generating pulse signals according to the magnitude of the leakage current signals when the magnitude of the leakage current signals is larger than a preset threshold value; and the at least two output pins are connected with the analog-to-digital conversion circuit in a one-to-one correspondence manner and are used for outputting pulse signals. The leakage detection device is based on at least two paths of comparison circuits, an analog-to-digital conversion circuit and an output pin, and can output more complete information related to a leakage current signal.
Description
Technical Field
The present invention generally relates to the field of leakage detection, and more particularly, to a leakage detection device, a leakage detection method, 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.
Disclosure of Invention
In this summary, concepts in a simplified form are introduced that are further described in the detailed description. This summary of the 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 an electrical leakage detection apparatus, including:
the leakage current inductor is used for inducing a leakage current signal;
a control circuit, the control circuit comprising:
the comparison circuits are connected with the leakage current inductor and are used for comparing the leakage current signal with a preset threshold value;
the analog-to-digital conversion circuits are connected with the comparison circuits in a one-to-one correspondence mode and used for generating pulse signals according to the magnitude of the leakage current signals when the magnitude of the leakage current signals is larger than the preset threshold value;
and the at least two output pins are connected with the analog-to-digital conversion circuits in a one-to-one correspondence manner and are used for outputting the pulse signals.
In one embodiment, the control circuit further comprises:
the self-checking circuit is used for carrying out system self-checking to obtain a fault state signal;
the logic circuit is connected with the self-checking circuit and is used for generating a combined signal of a high-level signal and/or a low-level signal according to the fault state signal;
the logic circuit is further connected to the at least two output pins for outputting the combined signal through the at least two output pins.
In one embodiment, the control circuit further includes a self-test instruction input pin configured to receive a self-test instruction, where the self-test instruction is configured to trigger the self-test circuit to start performing the system self-test.
In one embodiment, the control circuit includes a first comparison circuit, a first analog-to-digital conversion circuit and a first output pin, which are connected in sequence, the first comparison circuit is configured to compare a leakage current signal with a first preset threshold, the first analog-to-digital conversion circuit is configured to generate a first pulse signal according to a magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the first preset threshold, and the first output pin is configured to output the first pulse signal;
the control circuit further comprises a second comparison circuit, a second analog-to-digital conversion circuit and a second output pin which are sequentially connected, the second comparison circuit is used for comparing the direct current component of the leakage current signal with a second preset threshold value, the second analog-to-digital conversion circuit is used for generating a second pulse signal according to the direct current component of the leakage current signal when the direct current component of the leakage current signal is larger than the second preset threshold value, and the second output pin is used for outputting the second pulse signal.
In one embodiment, the analog-to-digital conversion circuit is used for continuously outputting the pulse signal within a preset time.
In one embodiment, the analog-to-digital conversion circuit is configured to generate a pulse width modulation signal with a corresponding duty ratio according to a magnitude of the leakage current signal.
In one embodiment, the frequencies of the pulse signals generated by different analog-to-digital conversion circuits are the same or different.
In one embodiment, the analog-to-digital conversion circuit is configured to generate a pulse signal having a corresponding frequency according to a magnitude of the leakage current signal.
In one embodiment, the leakage current inductor comprises a zero sequence current transformer.
A second aspect of an embodiment of the present invention provides an electrical leakage detection apparatus, including:
the leakage current inductor is used for inducing a leakage current signal;
a control circuit, the control circuit comprising:
the comparison circuit is connected with the leakage current inductor and is used for comparing the leakage current signal with a preset threshold value;
the analog-to-digital conversion circuit is connected with the comparison circuit and is used for generating a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is larger than the preset threshold value;
the output pin is connected with the analog-to-digital conversion circuit and used for outputting the pulse signal;
the self-checking circuit is used for carrying out system self-checking to obtain a fault state signal;
the logic circuit is connected with the self-checking circuit and is used for generating a high-level signal or a low-level signal according to the fault state signal;
the logic circuit is further connected to the output pin, and is configured to output the high level signal or the low level signal through the output pin.
A third aspect of the embodiments of the present invention provides a leakage detection method, where the method includes:
inducing a leakage current signal, and comparing the leakage current signal with a preset threshold value;
when the magnitude of the leakage current signal is larger than the preset threshold, generating a pulse signal according to the magnitude of the leakage current signal, wherein the preset threshold at least comprises a first preset threshold and a second preset threshold, when the magnitude of the leakage current signal is larger than the first preset threshold, generating a pulse signal according to the magnitude of the leakage current signal, and when the direct current component of the leakage current signal is larger than the second preset threshold, generating a second pulse signal according to the magnitude of the direct current component;
and outputting different pulse signals through at least two output pins respectively.
In one embodiment, the method further comprises: carrying out system self-check to obtain a fault state signal; generating a combined signal of a high level signal and/or a low level signal according to the fault state signal; outputting the combined signal through the at least two output pins.
In one embodiment, outputting the pulse signal comprises: and continuously outputting the pulse signal within a preset time.
A fourth aspect of the embodiments 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 value
The leakage detection device, the leakage detection method and the charging equipment provided by the embodiment of the invention are based on at least two paths of comparison circuits, analog-to-digital conversion circuits and output pins, and can output more complete information related to leakage current signals.
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;
fig. 2 is a schematic flow chart of a leakage detection method 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 invention.
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 invention 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 invention. 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 invention, however, the invention is capable of other embodiments in addition to those detailed.
The current RCD 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.
In addition, when being applied to charging equipment such as charging stake or charging gun with the RCD, owing to involve the automotive industry, need RCD itself to have certain function safety policy to satisfy the partial function safety demand of automotive industry, need RCD itself promptly to have system self-checking and report the ability to the host computer with the self-checking result.
However, when a leakage current exists and reaches a set threshold, the conventional RCD can only output a pure high-low level (0 or 1) signal, and the client can only determine whether a leakage fault exists, and cannot know the magnitude of the leakage current signal when the leakage fault occurs, and therefore cannot upload the information of the magnitude of the leakage current to a higher-level system, cannot know the type of the leakage current, and cannot transmit self-diagnosis information of the RCD leakage module to the higher-level system. If the client needs to obtain complete leakage current information, an analog RCD is necessary, and an additional algorithm is needed, which has the following disadvantages:
1) algorithm compiling related to RCD electric leakage needs strong specialty and is difficult to realize in many cases; in addition, the analog output mode can finish measurement with higher precision only by simultaneously sampling multiple ADC sampling channels, so that an additional hardware circuit is required to realize the measurement, and the design cost is obviously increased;
2) the analog RCD has many contents related to EMC (Electronic Magnetic Compatibility), and if traps of these professional experiments cannot be avoided, a large amount of manpower and material resources will be wasted, and the development cost and time will be increased.
In view of the foregoing problems, embodiments of the present invention provide a leakage detection device, a leakage detection method, and a charging device, which are based on at least two comparison circuits, an analog-to-digital conversion circuit, and an output pin, and can output information related to the magnitude of a leakage current signal and transmit information related to the waveform of the leakage current signal.
The following describes a leakage detection device, a leakage detection method, and a charging device in detail, according to embodiments of the present invention, with reference to the accompanying 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, where the leakage current sensor 101 is configured to sense a leakage current signal; the control circuit 102 includes: each comparison circuit is respectively connected with the leakage current inductor and is used for comparing the leakage current signal with a corresponding preset threshold value; the analog-to-digital conversion circuits are connected with the comparison circuits in a one-to-one correspondence mode and used for generating pulse signals according to the magnitude of the leakage current signals when the magnitude of the leakage current signals is larger than the corresponding preset threshold value; and the output pins are connected with the analog-to-digital conversion circuits in a one-to-one correspondence manner and used for outputting pulse signals.
The leakage detection device comprises at least two paths of comparison circuits, an analog-to-digital conversion circuit and an output pin, wherein each path of comparison circuit, each analog-to-digital conversion circuit and each output pin respectively output corresponding leakage current information, so that the leakage detection device can output information related to the magnitude of leakage current and can also transmit information related to the waveform of the leakage current. According to the at least two paths of pulse signals output by the leakage detection device, the client can judge whether leakage occurs or not, can directly read the leakage current information and read the leakage current waveform information, for example, the client judges whether the leakage is direct current leakage or alternating current leakage according to the output pins of the output pulse signals, so that the client does not need to write an additional algorithm to read the leakage information, the development cost and the development time are saved, and a foundation is laid for interconnection of leakage system information.
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 103 is further included between the zero sequence current transformer and the control circuit 102, and the control circuit 102 obtains the leakage current signal through the sampling resistor 103. And, also include the oscillating circuit (OSC) set up between zero sequence current transformer 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 103, the voltage information includes the information of the magnetic flux of 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 103 with the voltage configured in advance by the comparator, and the feedback signal is fed back to an excitation circuit in the controller 102 to adjust the frequency of the excitation current until the circuit is in a stable state, and then the excitation frequency also tends to be stable.
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 includes at least two comparison circuits, an analog-to-digital conversion circuit, and an output pin, each for outputting information related to a type of leakage current signal, including but not limited to an ac leakage current signal and a dc component of the leakage current signal.
The comparison circuit is connected with the leakage current inductor and used for comparing the leakage current signal with a corresponding preset threshold value, namely the comparison circuit is used for judging whether the power supply line needs to be disconnected or not. The preset threshold values of different comparison circuits may be the same or different, and may specifically depend on the type of the leakage current signal corresponding to the comparison circuit.
The analog-to-digital conversion circuit is used for performing analog-to-digital conversion according to the type and the magnitude of the leakage current signal so as to generate an analog signal, namely a pulse signal, representing the magnitude of the leakage current signal. The pulse signal may indicate not only the magnitude of the leakage current signal but also waveform information of the leakage current signal, a frequency of the leakage current signal, and the like. Illustratively, the analog-to-digital conversion circuit may generate a PWM (Pulse Width Modulation) signal having a corresponding duty ratio according to the magnitude of the leakage current signal. The duty ratio of the PWM signal, namely the proportion of a high level in the whole period in a pulse period, the higher the magnitude of the leakage current signal is, the higher the duty ratio of the PWM signal generated by the analog-to-digital conversion circuit is, the client can determine the magnitude of the leakage current signal according to the duty ratio of the PWM signal, and simultaneously determine the type of the leakage current signal according to a pin outputting the PWM signal, so that the purpose of representing the magnitude and the type of the leakage current signal through a digital signal is achieved, and no additional algorithm is required to be configured at the client. For example, the frequencies of the PWM signals generated by the different analog-to-digital conversion circuits may be the same or different, and in some embodiments, the frequency of the ac leakage current signal may be represented by the frequency of the PWM signal in addition to the magnitude of the leakage current signal being represented by the duty ratio of the PWM signal.
In another embodiment, the analog-to-digital conversion circuit is configured to generate a frequency modulation signal having a corresponding frequency according to the magnitude of the leakage current signal, for example, the larger the magnitude of the leakage current signal is, the higher the frequency of the output digital signal is, and the client may determine the magnitude of the leakage current signal according to the frequency of the digital signal.
In some embodiments, since the output of the output pin is abruptly changed from 0 to the pulse signal when the leakage current signal is greater than the preset threshold, the client may control the actuator to perform a line break when recognizing a rising edge of the pulse signal. Then, the control circuit 102 locks the output pin and keeps outputting the pulse signal continuously within a preset time, so that the client has enough time to complete sampling of the duty ratio of the PWM signal, thereby obtaining the magnitude of the corresponding leakage current signal. Optionally, in some embodiments, when the leakage current signal is greater than the preset threshold, the control circuit may also control the output pin to output a high-low level signal to notify the client of the leakage fault, and then output a pulse signal with a period of time to notify the client of the magnitude of the leakage current signal.
Referring to fig. 1, in a specific embodiment, the control circuit 102 includes a first comparison circuit, a first analog-to-digital conversion circuit and a first output pin, which are connected in sequence, the first comparison circuit is configured to compare the total leakage current signal with a first preset threshold, the first analog-to-digital conversion circuit is configured to generate a first pulse signal according to a magnitude of the total leakage current signal when the magnitude of the total leakage current signal is greater than the first preset threshold, and the first output pin is configured to output the first pulse signal. The total leakage current signal includes a total leakage current signal of an ac component and a dc component.
The control circuit 102 further includes a second comparison circuit, a second analog-to-digital conversion circuit, and a second output pin, which are connected in sequence, where the second comparison circuit is configured to compare a direct current component of the leakage current signal with a second preset threshold, the second analog-to-digital conversion circuit is configured to generate a second pulse signal according to the magnitude of the direct current component of the leakage current signal when the magnitude of the direct current component of the leakage current signal is greater than the second preset threshold, and the second output pin is configured to output the second pulse signal.
Therefore, according to the first pulse signal, the client can obtain the total alternating current and direct current value of the leakage current signal, and meanwhile, according to the second pulse signal, the client can know the magnitude of the direct current component of the leakage current signal.
Taking the first preset threshold value of 30mA as an example, when the magnitude of the ac leakage current signal is greater than 30mA, the output of the first output pin (i.e., 30mA PWM OUT in fig. 1) is suddenly changed from 0 level to a PWM signal with a duty ratio corresponding to 30mA, the frequency of the output PWM signal is, for example, 8K Hz, and the output signal of the first output pin is locked for a certain time, for example, 500ms, so that the client can recognize the existence of high level and immediately send OUT a TRIP (break) signal to break the power supply line in a specified time, and at the same time, enough time can be provided to complete sampling of the duty ratio of the PWM signal to obtain a corresponding ac leakage current value and upload the ac leakage information to a higher-level system.
Taking the second preset threshold value as 6mA as an example, when the magnitude of the dc component of the leakage current signal is greater than 6mA, the output of the second output pin (i.e. 6mA PWM OUT in fig. 1) is suddenly changed from 0 level to a PWM signal with a duty ratio corresponding to 6mA, the frequency of the output PWM signal is, for example, 8K Hz, and the output signal of the second output pin is locked for a certain time, for example, 500ms, so that the client can recognize the existence of the high level and immediately send OUT a TRIP signal to break the line within a specified time, and at the same time, enough time can be provided to complete sampling of the duty ratio of the PWM signal, so as to obtain a corresponding dc leakage current value, and upload dc leakage information to a higher-level system.
It should be noted that the above values are provided as examples only, the frequency of the PWM signal is not limited to 8K Hz, but may be any suitable frequency, and the frequencies of different PWM signals may be the same or different; in addition, the time for the lock output pin to output the PWM signal is not limited to 500ms, and may be any suitable time.
Illustratively, the control circuit 102 may include a power VCC pin, a GND ground pin, a calibration pin, etc., in addition to the output pin, which will not be described in detail herein.
The output pin of the embodiment of the present invention may be used to output a high-low level signal in addition to a pulse signal such as a PWM signal to indicate the type of fault. Specifically, the control circuit 102 further includes: the self-checking circuit is used for carrying out system self-checking to obtain fault state signals, such as ZCT disconnection, short circuit, MCU RAM or Flash error and the like; and a logic circuit connected with the self-checking circuit and used for generating a combined signal of a high level signal and/or a low level signal according to the fault state signal. The logic circuit is also connected with the at least two output pins and is used for outputting the combined signal through the at least two output pins. Therefore, by multiplexing the output pins, the leakage detection device provided by the embodiment of the invention not only can output the relevant information of the complete leakage current signal, but also can output the information relevant to the fault state, and lays a foundation for the interconnection of the leakage system information. The embodiment of the invention does not limit the manner of obtaining the fault state signal, and the fault state signal can be obtained in any form based on a self-checking circuit in any form.
With continued reference to fig. 1, IN one embodiment, the control circuit 102 further includes a self-TEST command input pin (TEST IN) for receiving an external self-TEST command (e.g., high or low level 0 or 1), which is used to trigger the self-TEST circuit to start system self-TEST, resulting IN a fault status signal. Besides the mode of receiving the self-test instruction, the system self-test can also be triggered by other modes, such as a PWM mode, a timing self-test, a self-test when a current leakage phenomenon occurs, and the like.
When the output pins include a first output pin and a second output pin, the first output pin may output a high level signal and a low level signal, and the second output pin may also output a high level signal and a low level signal, so that four combined signals may be output through the two output pins, each of which may indicate one or more fault types, see table 1. Since the output pins of the embodiment of the present invention are not limited to two, but may be three or more, when N output pins are provided, 2 can be outputNThe signals are combined.
TABLE 1
In the example of table 1, when the first output pin outputs a low level (0) and the second output pin outputs a low level (0), the client confirms that the system state is one of a standby state and a self-test failure state; when the first output pin outputs a low level (0) and the second output pin outputs a high level (1), the client confirms that the system state is a ZCT winding turn full short circuit, and so on. Therefore, by multiplexing the two output pins, various system states can be output, and the indication of the self-checking fault state is realized by the functional mode of pin multiplexing. Of course, it is understood that the indication of the operating state is not limited to the ones shown in table 1, and that each combination signal may represent more or less states.
Based on the above description, the leakage detection apparatus according to the embodiment of the present invention is capable of outputting more complete information related to the leakage current signal based on at least two paths of the comparison circuit, the analog-to-digital conversion circuit, and the output pin; meanwhile, the fault state information can be output by multiplexing the output pins.
Another aspect of an embodiment of the present invention provides an electrical leakage detection apparatus, including: the leakage current inductor is used for inducing a leakage current signal; a control circuit, the control circuit comprising: the comparison circuit is connected with the leakage current inductor and is used for comparing the leakage current signal with a preset threshold value; the analog-to-digital conversion circuit is connected with the comparison circuit and is used for generating a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is larger than a preset threshold value; the output pin is connected with the analog-to-digital conversion circuit and used for outputting a pulse signal; the self-checking circuit is used for carrying out system self-checking to obtain a fault state signal; the logic circuit is connected with the self-checking circuit and used for generating a high-level signal or a low-level signal according to the fault state signal; the logic circuit is also connected with the output pin and is used for outputting the high level signal or the low level signal through the output pin.
The difference from the leakage detection device described with reference to fig. 1 is that the leakage detection device of the present embodiment includes only one output pin, and the output pin is used to implement two functions, and in addition to outputting a pulse signal representing the magnitude of the leakage current based on the output pin, the output pin also outputs a high-low level signal representing a fault state, so that the client can timely know the leakage information and the fault state. Since the leakage detecting device of the present embodiment includes only one output pin, the output pin can output two signals, i.e., a high level signal and a low level signal, each of which indicates one or more fault states.
In addition, the leakage detecting device of the present embodiment and the leakage detecting device described above have many the same or similar contents, and further details can refer to the related description above, which are not repeated herein.
In another aspect, the embodiment of the present invention provides a leakage detection method, which may be implemented by the leakage detection apparatus described with reference to fig. 1. Only the main steps for describing the leakage detection method will be described below, and more details can be referred to above.
FIG. 2 shows a schematic flow diagram of a method 200 of electrical leakage detection according to one embodiment of the present invention. As shown in fig. 2, the leakage detecting method 200 according to the embodiment of the present invention includes the following steps:
in step S210, a leakage current signal is obtained, and the leakage current signal is compared with a preset threshold corresponding to the type of the leakage current signal;
in step S220, when the magnitude of the leakage current signal is greater than the preset threshold, generating a pulse signal according to the magnitude and the type of the leakage current signal, where the pulse signal at least includes a first pulse signal corresponding to a first type of leakage current signal and a second pulse signal corresponding to a second type of leakage current signal;
in step S230, the different pulse signals are output through at least two output pins, respectively.
As described above, in step S210, a leakage current signal may be induced by a leakage current sensor such as ZCT, and obtained by detecting a voltage across a sampling resistor. The type of the leakage current signal includes, but is not limited to, an ac signal, a dc signal, and for example, the total leakage current signal including an ac component and a dc component may be compared with a first preset threshold value by a first comparison circuit, and the dc component may be compared with a second preset threshold value by a second comparison circuit.
In step S220, when the magnitude of the leakage current signal is greater than the preset threshold, a pulse signal is generated according to the magnitude and type of the leakage current signal, where the pulse signal includes, but is not limited to, a PWM signal, and specifically, the magnitude of the leakage current signal may be represented by a duty ratio of the PWM signal, and the type of the leakage current signal may be represented by a pin outputting the PWM signal. The pulse signals at least comprise a first pulse signal corresponding to the first type of leakage current signals and a second pulse signal corresponding to the second type of leakage current signals. For example, the first pulse signal may correspond to a total leakage current signal, and the magnitude of the total leakage current signal may be obtained according to a duty ratio of the first pulse signal; the second pulse signal may correspond to a dc component of the leakage current signal, and the magnitude of the dc component of the leakage current signal may be obtained according to a duty ratio of the second pulse signal.
It should be noted that the pulse signal is not limited to two pulse signals, but may include three or more pulse signals, each corresponding to a different type of leakage current signal.
Thereafter, in step S230, different pulse signals are output through at least two output pins, respectively. For example, the first pulse signal may be output through the first output pin, and the second pulse signal may be output through the second output pin. If more pulse signals are generated, more output pins may be set accordingly. Further, outputting the pulse signal includes: and continuously outputting the pulse signal within a preset time, namely locking the output pin to continuously output the pulse signal for a period of time, so that the client can sample the pulse signal to obtain the magnitude of the leakage current signal.
In some embodiments, the leakage detection method 200 further comprises: carrying out system self-check to obtain a fault state signal; generating a combined signal of a high level signal and/or a low level signal according to the fault state signal; outputting the combined signal through the at least two output pins. Through multiplexing the output pins, the information such as the size and the type of a leakage current signal can be output, and the fault state information can also be output, so that a client can conveniently identify the fault type.
Specifically, after obtaining the fault state signal, based on preset logic, generating a high-low level combined signal corresponding to the fault state signal, and enabling each output pin to output one of the high-level signal and the low-level signal, wherein the two output pins can output four combined signals, and each combined signal represents one or more fault types.
In one embodiment, the leakage detection method 200 further includes: and receiving a self-checking instruction, and triggering the system self-checking according to the self-checking instruction. In other embodiments, the system self-check may be performed when other preset conditions are met, for example, the system self-check may be performed when an electrical leakage occurs, or the system self-check may be performed periodically.
According to the leakage detection method, more complete information related to the leakage current signal can be output; meanwhile, the fault state information can be output by multiplexing the output pins.
The embodiment of the invention 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 invention 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. Meanwhile, the leakage detection device in the charging device in the embodiment of the invention also has the capability of reporting the size and the type of the leakage current signal and the capability of reporting the self-detection result.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention 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 invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the invention 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 invention 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 invention 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 invention, 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 invention 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 person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and the changes or substitutions 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 (15)
1. An electrical leakage detection device, characterized in that it comprises:
the leakage current inductor is used for inducing a leakage current signal;
a control circuit connected to the leakage current inductor, the control circuit comprising:
the comparison circuits are connected with the leakage current inductor and are used for comparing the leakage current signal with a corresponding preset threshold value;
the analog-to-digital conversion circuits are connected with the comparison circuits in a one-to-one correspondence mode and used for generating pulse signals according to the magnitude of the leakage current signals when the magnitude of the leakage current signals is larger than the preset threshold value;
and the at least two output pins are connected with the analog-to-digital conversion circuits in a one-to-one correspondence manner and are used for outputting the pulse signals.
2. The electrical leakage detection apparatus of claim 1, wherein the control circuit further comprises:
the self-checking circuit is used for carrying out system self-checking to obtain a fault state signal;
the logic circuit is connected with the self-checking circuit and is used for generating a combined signal of a high-level signal and/or a low-level signal according to the fault state signal;
the logic circuit is further connected to the at least two output pins for outputting the combined signal through the at least two output pins.
3. The electrical leakage detection device according to claim 2, wherein the control circuit further comprises a self-test command input pin connected to the self-test circuit, and configured to receive a self-test command, and the self-test command is configured to trigger the self-test circuit to start performing the system self-test.
4. The leakage detection device according to claim 1, wherein the control circuit comprises a first comparison circuit, a first analog-to-digital conversion circuit and a first output pin, which are connected in sequence, the first comparison circuit is configured to compare the leakage current signal with a first preset threshold, the first analog-to-digital conversion circuit is configured to generate a first pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the first preset threshold, and the first output pin is configured to output the first pulse signal;
the control circuit further comprises a second comparison circuit, a second analog-to-digital conversion circuit and a second output pin which are sequentially connected, the second comparison circuit is used for comparing the direct current component of the leakage current signal with a second preset threshold value, the second analog-to-digital conversion circuit is used for generating a second pulse signal according to the direct current component of the leakage current signal when the direct current component of the leakage current signal is larger than the second preset threshold value, and the second output pin is used for outputting the second pulse signal.
5. The electrical leakage detection device of claim 1, wherein the output pin is configured to output the pulse signal continuously for a predetermined time.
6. The leakage detection device of claim 1, wherein the analog-to-digital conversion circuit is configured to generate a pulse width modulation signal having a corresponding duty cycle according to a magnitude of the leakage current signal.
7. The leakage detection device of claim 6 wherein the frequencies of the pulse width modulated signals generated by different analog-to-digital conversion circuits are the same or different.
8. The leakage detection device of claim 1, wherein the analog-to-digital conversion circuit is configured to generate a frequency modulation signal having a corresponding frequency according to a magnitude of the leakage current signal.
9. The electrical leakage detection device of claim 1, wherein the leakage current inductor comprises a zero sequence current transformer.
10. An electrical leakage detection device according to claim 9, further comprising:
the sampling resistor is arranged between the zero sequence current transformer and the control circuit, and the control circuit obtains the leakage current signal through the sampling resistor;
and the oscillating circuit is arranged between the zero sequence current transformer and the control circuit, and the control circuit applies excitation current to the zero sequence current transformer through the oscillating circuit.
11. An electrical leakage detection device, characterized in that it comprises:
the leakage current inductor is used for inducing a leakage current signal;
a control circuit, the control circuit comprising:
the comparison circuit is connected with the leakage current inductor and is used for comparing the leakage current signal with a preset threshold value;
the analog-to-digital conversion circuit is connected with the comparison circuit and is used for generating a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is larger than the preset threshold value;
the output pin is connected with the analog-to-digital conversion circuit and used for outputting the pulse signal;
the self-checking circuit is used for carrying out system self-checking to obtain a fault state signal;
the logic circuit is connected with the self-checking circuit and is used for generating a high-level signal or a low-level signal according to the fault state signal;
the logic circuit is further connected to the output pin, and is configured to output the high level signal or the low level signal through the output pin.
12. A method of electrical leakage detection, the method comprising:
acquiring a leakage current signal, and comparing the leakage current signal with a preset threshold corresponding to the type of the leakage current signal;
when the magnitude of the leakage current signal is larger than the preset threshold value, generating a pulse signal according to the magnitude and the type of the leakage current signal, wherein the pulse signal at least comprises a first pulse signal corresponding to a first type of leakage current signal and a second pulse signal corresponding to a second type of leakage current signal;
and outputting different pulse signals through at least two output pins respectively.
13. A leakage detecting method according to claim 12, further comprising:
carrying out system self-check to obtain a fault state signal;
generating a combined signal of a high level signal and/or a low level signal according to the fault state signal;
outputting the combined signal through the at least two output pins.
14. The electrical leakage detection method according to claim 12, wherein outputting the pulse signal comprises:
and continuously outputting the pulse signal within a preset time.
15. A charging apparatus, characterized in that the charging apparatus comprises:
the electrical leakage detection device according to any one of claims 1 to 11;
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.
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| CN202110501017.5A CN113296019A (en) | 2021-05-08 | 2021-05-08 | Electric leakage detection device, electric leakage detection method and charging equipment |
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| CN202110501017.5A CN113296019A (en) | 2021-05-08 | 2021-05-08 | Electric leakage detection device, electric leakage detection method and charging equipment |
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| CN113759288A (en) * | 2021-11-08 | 2021-12-07 | 深圳市德兰明海科技有限公司 | Leakage current detection circuit and method and leakage current detector |
| CN113809715A (en) * | 2021-09-25 | 2021-12-17 | 浙江巨磁智能技术有限公司 | High-integration-level multifunctional protection method for IC-CPD |
| CN114113721A (en) * | 2021-12-03 | 2022-03-01 | 康熹智能科技（东莞）有限公司 | Smart electric meter with electric leakage prompt function |
| WO2024001825A1 (en) * | 2022-06-30 | 2024-01-04 | 芯海科技（深圳）股份有限公司 | Sigma-delta analog-to-digital converter, control method, chip and electronic device |
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| CN113809715A (en) * | 2021-09-25 | 2021-12-17 | 浙江巨磁智能技术有限公司 | High-integration-level multifunctional protection method for IC-CPD |
| CN113809715B (en) * | 2021-09-25 | 2023-12-08 | 浙江巨磁智能技术有限公司 | High-integration multifunctional protection method for IC-CPD |
| CN113759288A (en) * | 2021-11-08 | 2021-12-07 | 深圳市德兰明海科技有限公司 | Leakage current detection circuit and method and leakage current detector |
| CN113759288B (en) * | 2021-11-08 | 2022-03-11 | 深圳市德兰明海科技有限公司 | Leakage current detection circuit and method and leakage current detector |
| CN114113721A (en) * | 2021-12-03 | 2022-03-01 | 康熹智能科技（东莞）有限公司 | Smart electric meter with electric leakage prompt function |
| CN114113721B (en) * | 2021-12-03 | 2024-03-19 | 江阴众和电力仪表有限公司 | Smart electric meter with electric leakage prompt facility |
| WO2024001825A1 (en) * | 2022-06-30 | 2024-01-04 | 芯海科技（深圳）股份有限公司 | Sigma-delta analog-to-digital converter, control method, chip and electronic device |
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