A leakage detection device, a leakage detection method, and a charging device

Abstract

A leakage detection device, a leakage detection method, and a charging device. The leakage detection device includes: a leakage current inductor for sensing a leakage current signal; a control circuit connected to the leakage current inductor. The control circuit includes: at least two comparison circuits connected to the leakage current inductor for comparing the leakage current signal with corresponding preset thresholds; at least two analog-to-digital conversion circuits connected to the comparison circuits in one-to-one correspondence. The analog-to-digital conversion circuit is used to generate a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the preset threshold; at least two output pins connected to the analog-to-digital conversion circuits in one-to-one correspondence for outputting the pulse signal. Based on at least two paths of comparison circuits, analog-to-digital conversion circuits, and output pins, the leakage detection device can output more complete information related to the leakage current signal.

Description

Technical Field

[0001] 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 device. Background Art

[0002] An RCD (Residual Current Device) is a leakage detection device used to detect the magnitude of the leakage current in a circuit. If an RCD is not installed in the circuit, when a person or an animal comes into contact with high voltage, a leakage current will be generated to the ground. When the leakage current exceeds a certain threshold, it will cause fibrillation of the heart of the person or animal, leading to cardiac arrest and thus posing a life threat. If an RCD such a leakage detection device is installed in the circuit, when there is a leakage current in the circuit and the magnitude of the leakage current signal exceeds the set threshold, the RCD will send an alarm signal to the actuating mechanism to trigger the actuating mechanism to quickly disconnect the circuit, thereby achieving the purpose of protecting life safety.

[0003] The main purpose of the actuating mechanism is to disconnect the circuit supplying power to the rear end. After the circuit is disconnected, there will be no voltage and current at the rear end of the disconnector, thus achieving the purpose of protection. The on-board leakage module of the RCD is currently widely used in charging piles and charging guns, and it can be directly installed on the circuit board. When an electric vehicle is charging, the RCD is used to detect whether the leakage current during charging exceeds the threshold. If it exceeds the threshold, the RCD will send an alarm signal to other devices in the circuit board to execute the command to stop charging and disconnect the charging circuit, such as disconnecting a closed relay or circuit breaker mechanism, etc. Summary of the Invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0005] An embodiment of the present invention provides a leakage detection device on the one hand, and the leakage detection device includes:

[0006] A leakage current inductor for sensing a leakage current signal;

[0007] A control circuit, and the control circuit includes:

[0008] At least two comparison circuits, the comparison circuits are connected to the leakage current inductor and are used to compare the leakage current signal with a preset threshold;

[0009] At least two analog-to-digital conversion circuits, which are connected to the comparison circuit in a one-to-one correspondence, and the analog-to-digital conversion circuit is configured to generate a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the preset threshold value;

[0010] At least two output pins, which are connected to the analog-to-digital conversion circuit in a one-to-one correspondence, and are used for outputting the pulse signal.

[0011] In one embodiment, the control circuit further includes:

[0012] A self-checking circuit, which is used for performing system self-checking to obtain a fault status signal;

[0013] A logic circuit, which is connected to 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 status signal;

[0014] The logic circuit is further connected to the at least two output pins and is used for outputting the combined signal through the at least two output pins.

[0015] In one embodiment, the control circuit further includes a self-checking instruction input pin, which is used for receiving a self-checking instruction, and the self-checking instruction is used for triggering the self-checking circuit to start performing the system self-checking.

[0016] 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 used for comparing the leakage current signal with a first preset threshold value. The first analog-to-digital conversion circuit is used for generating 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 value. The first output pin is used for outputting the first pulse signal;

[0017] The control circuit further includes a second comparison circuit, a second analog-to-digital conversion circuit and a second output pin which are connected in sequence. The second comparison circuit is used for comparing the DC 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 magnitude of the DC component of the leakage current signal when the magnitude of the DC component of the leakage current signal is greater than the second preset threshold value. The second output pin is used for outputting the second pulse signal.

[0018] In one embodiment, the analog-to-digital conversion circuit is configured to continuously output the pulse signal within a preset time.

[0019] In one embodiment, the analog-to-digital conversion circuit is configured to generate a pulse width modulation signal with a corresponding duty cycle according to the magnitude of the leakage current signal.

[0020] In one embodiment, the frequencies of the pulse signals generated by different analog-to-digital conversion circuits are the same or different.

[0021] In one embodiment, the analog-to-digital conversion circuit is configured to generate a pulse signal with a corresponding frequency according to the magnitude of the leakage current signal.

[0022] In one embodiment, the leakage current inductor includes a zero-sequence current transformer.

[0023] A second aspect of the embodiments of the present invention provides a leakage detection device, which includes:

[0024] A leakage current inductor for sensing a leakage current signal;

[0025] A control circuit, where the control circuit includes:

[0026] A comparison circuit, the comparison circuit is connected to the leakage current inductor and is configured to compare the leakage current signal with a preset threshold;

[0027] An analog-to-digital conversion circuit, connected to the comparison circuit, the analog-to-digital conversion circuit is configured to generate a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the preset threshold;

[0028] An output pin, connected to the analog-to-digital conversion circuit, for outputting the pulse signal;

[0029] A self-checking circuit for performing system self-checking to obtain a fault status signal;

[0030] A logic circuit, connected to the self-checking circuit, for generating a high-level signal or a low-level signal according to the fault status signal;

[0031] 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.

[0032] A third aspect of the embodiments of the present invention provides a leakage detection method, which includes:

[0033] Sensing a leakage current signal and comparing the leakage current signal with a preset threshold;

[0034] When the magnitude of the leakage current signal is greater than the preset threshold, generating a pulse signal according to the magnitude of the leakage current signal, where the preset threshold includes at least a first preset threshold and a second preset threshold. When the magnitude of the leakage current signal is greater than the first preset threshold, generating a pulse signal according to the magnitude of the leakage current signal. When the DC component of the leakage current signal is greater than the second preset threshold, generating a second pulse signal according to the magnitude of the DC component;

[0035] Output different ones of the pulse signals through at least two output pins respectively.

[0036] In one embodiment, the method further includes: performing a system self-check to obtain a fault status signal; generating a combined signal of a high-level signal and / or a low-level signal according to the fault status signal; outputting the combined signal through the at least two output pins.

[0037] In one embodiment, outputting the pulse signal includes: continuously outputting the pulse signal within a preset time.

[0038] A fourth aspect of an embodiment of the present invention provides a charging device, which includes the above-mentioned leakage detection device and an actuating mechanism connected to the leakage detection device. The actuating mechanism is used to disconnect the power supply line when the magnitude of the leakage current signal detected by the leakage detection device is greater than a preset threshold.

[0039] The leakage detection device, leakage detection method, and charging device of the embodiments of the present invention can output more complete information related to the leakage current signal based on at least two comparison circuits, an analog-to-digital conversion circuit, and output pins. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] By describing the embodiments of the present application in more detail in conjunction with the drawings, the above-mentioned and other objects, features, and advantages of the present application will become more obvious. The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application, and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0041] Figure 1 is a circuit diagram of a leakage detection device according to an embodiment of the present invention;

[0042] Figure 2 is a schematic flowchart of a leakage detection method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, some well-known technical features are not described to avoid confusion with the present invention.

[0044] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. On the contrary, 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 dimensions and relative dimensions of layers and regions may be exaggerated for clarity. Like reference numerals throughout the figures denote like elements.

[0045] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, 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" another element or layer, there are no intervening elements or layers. It should 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 may be denoted as a second element, component, region, layer or section without departing from the teachings of the present invention.

[0046] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. may be used herein for convenience in describing the relationship of one element or feature to another element or feature shown in the figures. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, then an element or feature described as "under" or "beneath" or "underneath" another element or feature will be oriented "over" the other element or feature. Thus, the exemplary terms "under" and "beneath" can include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are to be interpreted accordingly.

[0047] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, specify the presence of the 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. As used herein, the term "and / or" includes any and all combinations of the related listed items.

[0048] To thoroughly understand the present invention, detailed structures will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other embodiments.

[0049] Current RCDs are available in both analog and digital forms. The analog RCD directly outputs the waveform and amplitude of the leakage current. If the controller of the client needs to know the waveform information and magnitude of the leakage current, it must perform sampling calculations through its own ADC (Analog-to-Digital Converter) to determine, and then decide whether to perform a line disconnection operation based on the calculation results. This method will increase the workload of the client and even pose a relatively high EMC (Electronic Magnetic Compatibility) risk.

[0050] For digital RCDs, when the leakage current value reaches its set threshold, it directly outputs digital high and low level signals (0 or 1). The controller of the client only needs to identify the high and low level signals to perform the corresponding disconnection action. This method is convenient, simple, easy to operate, reduces the workload of the client, and reduces the EMC risk of the client.

[0051] In addition, when applying the RCD to charging devices such as charging piles or charging guns, since it involves the automotive industry, the RCD itself needs to have certain functional safety strategies to meet some functional safety requirements of the automotive industry, that is, the RCD itself needs to have the ability of system self-check and report the self-check results to the host computer.

[0052] However, when there is a leakage current and it reaches the set threshold, the existing RCD can only output pure high and low level (0 or 1) signals. The client can only determine whether there is a leakage fault, but cannot know the magnitude of the leakage current signal when the leakage fault occurs, so it cannot upload the information about the magnitude of the leakage current to a higher-level system, cannot know the type of the leakage current, and even less can transmit the self-diagnosis information of the RCD leakage module to a higher-level system. If the client needs to obtain complete leakage current information, it must use an analog RCD and additional algorithms. This method has the following disadvantages:

[0053] 1) Writing algorithms related to RCD leakage requires strong professionalism and is difficult to implement in many cases. Moreover, the analog output method requires multiple ADC sampling channels to sample simultaneously to complete higher-precision measurement, which requires additional hardware circuits to achieve, significantly increasing the design cost;

[0054] 2) There are many contents related to EMC (Electronic Magnetic Compatibility) in the analog RCD. If the pitfalls of these professional experiments cannot be avoided, it will waste a lot of manpower and material resources, increasing the development cost and time.

[0055] In view of the above problems, the embodiments of the present invention provide a leakage detection device, a leakage detection method, and a charging device, which can output information related to the magnitude of the leakage current signal and convey information related to the waveform of the leakage current signal based on at least two comparison circuits, an analog-to-digital conversion circuit, and output pins.

[0056] The following will describe in detail the leakage detection device, the leakage detection method, and the charging device according to the embodiments of the present invention with reference to the accompanying drawings. Without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0057] See Figure 1 , the leakage detection device according to the embodiments of the present invention includes at least a leakage current inductor 101 and a control circuit 102. Among them, the leakage current inductor 101 is used to sense the leakage current signal; the control circuit 102 includes: at least two comparison circuits, each comparison circuit is respectively connected to the leakage current inductor and is used to compare the leakage current signal with a corresponding preset threshold; at least two analog-to-digital conversion circuits, the analog-to-digital conversion circuits are connected to the comparison circuits in one-to-one correspondence and are used to generate pulse signals according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the corresponding preset threshold; and at least two output pins, the output pins are connected to the analog-to-digital conversion circuits in one-to-one correspondence and are used to output the pulse signals.

[0058] The leakage detection device according to an embodiment of the present invention includes at least two comparison circuits, an analog-to-digital conversion circuit, and output pins. Each comparison circuit, analog-to-digital conversion circuit, and output pin respectively outputs corresponding leakage current information, so that it can not only output information related to the magnitude of the leakage current, but also convey information related to the waveform of the leakage current. According to at least two pulse signals output by the leakage detection device according to an embodiment of the present invention, the client can not only determine whether leakage occurs, but also directly read the magnitude information of the leakage current and the waveform information of the leakage current. For example, it can be determined whether the leakage is DC leakage or AC leakage according to the output pin of the output pulse signal, so that the client does not need to write additional algorithms to interpret the leakage information, saving development costs and development time, and laying a foundation for the interconnection of leakage system information.

[0059] The leakage detection device according to an embodiment of the present invention may adopt a fluxgate technology, and the leakage current inductor 101 therein may adopt a ZCT (Zero Current Transformer). Refer to Figure 1 , the primary side three-phase wires of the zero-sequence current transformer pass through the iron core, and the secondary coil is wound around the iron core. Under normal circumstances, the three-phase currents on the primary side of the zero-sequence current transformer are symmetrical, and the vector sum is zero. When a single-phase ground fault occurs in the system, the sum of the three-phase currents is not zero, and a zero-sequence magnetic flux appears in the iron core. This magnetic flux induces an electromotive force on the secondary coil and generates a secondary current.

[0060] Furthermore, the leakage detection device according to an embodiment of the present invention may adopt a type B leakage detection device, so that it can not only detect AC leakage and pulsating DC leakage, but also has the ability to detect 2P-DC (two-phase rectification), 3P-DC (three-phase rectification), S-DC (smooth DC), and F-type (10 Hz, 50 Hz, 1000 Hz) composite waves.

[0061] Specifically, in the type B leakage detection device, there is also a sampling resistor 103 provided between the zero-sequence current transformer and the control circuit 102. The control circuit 102 obtains the leakage current signal through the sampling resistor 103. And, there is also an oscillation circuit (OSC) provided between the zero-sequence current transformer and the control circuit 102. The control circuit 102 applies an excitation current to the zero-sequence current transformer through the oscillation circuit to drive the ZCT coil, so that its magnetic core is magnetized. At the same time, the control circuit 102 can obtain waveform signal voltage information including the excitation voltage waveform by detecting the voltage on the sampling resistor 103. This voltage information also includes the information of the zero-sequence magnetic flux; by filtering out the information of the excitation waveform, the information of the zero-sequence magnetic flux can be obtained. Since the zero-sequence magnetic flux is generated by the leakage current, the information of the leakage current can be obtained, realizing the function of detecting AC and DC leakage currents.

[0062] Further, the leakage detection device can adopt an open-loop or closed-loop excitation method. The excitation frequency in the open-loop excitation method is generated by an oscillation circuit, and the oscillation frequency is comprehensively determined according to the characteristics of different current transformers and the magnitude of the drive current signal. Once the excitation frequency is determined, it is fixed and cannot be arbitrarily modified during the application process. In the closed-loop excitation method, the excitation frequency is related to characteristic parameters such as the number of turns of the ZCT current transformer, Bm, coil excitation voltage, and cross-sectional area Ac. By comparing the voltage generated on the sampling resistor 103 with the voltage pre-configured in the comparator, a feedback signal is generated, and the feedback signal is fed back to the excitation circuit in the controller 102 to adjust the frequency of the excitation current until the circuit is in a stable state, and at this time the excitation frequency also tends to be stable.

[0063] It should be noted that the leakage current detector adopted in the embodiment of the present invention is not limited to the ZCT using the magnetic modulation technology. For example, the leakage current sensing function can also be implemented by using the Hall method or any other suitable method.

[0064] The leakage current inductor 101 is connected to the control circuit 102, and the control circuit 102 can be implemented as an MCU (micro control unit), or can also be implemented as other control units or circuits with similar functions. The control circuit 102 includes at least two comparison circuits, an analog-to-digital conversion circuit, and output pins. Each comparison circuit, analog-to-digital conversion circuit, and output pin is used to output information related to a type of leakage current signal, including but not limited to an alternating current leakage current signal and a direct current component of the leakage current signal.

[0065] Among them, the comparison circuit is connected to the leakage current inductor and is used to compare the leakage current signal with a corresponding preset threshold, that is, the comparison circuit is used to determine whether the power supply line needs to be disconnected. Among them, the preset thresholds of different comparison circuits can be the same or different, which can specifically depend on the type of leakage current signal corresponding to the comparison circuit.

[0066] The analog-to-digital conversion circuit is used to perform analog-to-digital conversion according to the type and magnitude of the leakage current signal to generate an analog signal representing the magnitude of the leakage current signal, that is, a pulse signal. In addition to being able to represent the magnitude of the leakage current signal, the pulse signal can also represent waveform information of the leakage current signal, the frequency of the leakage current signal, etc. Exemplarily, the analog-to-digital conversion circuit can generate a PWM (Pulse Width Modulation) signal with a corresponding duty cycle according to the magnitude of the leakage current signal. The duty cycle of the PWM signal is the proportion of the high level in the entire cycle within a pulse period. The higher the magnitude of the leakage current signal, the higher the duty cycle of the PWM signal generated by the analog-to-digital conversion circuit. The client can determine the magnitude of the leakage current signal according to the duty cycle of the PWM signal, and at the same time determine the type of the leakage current signal according to the pin outputting the PWM signal, so as to achieve the purpose of representing the magnitude and signal type of the leakage current signal through digital signals without configuring additional algorithms on the client. Exemplarily, the frequencies of the PWM signals generated by different analog-to-digital conversion circuits can be the same or different. In some embodiments, in addition to representing the magnitude of the leakage current signal through the duty cycle of the PWM signal, the frequency of the AC leakage current signal can also be represented through the frequency of the PWM signal.

[0067] In another embodiment, the analog-to-digital conversion circuit is used to generate a frequency modulation signal with a corresponding frequency according to the magnitude of the leakage current signal. For example, the larger the magnitude of the leakage current signal, the higher the frequency of the output digital signal. The client can determine the magnitude of the leakage current signal according to the frequency of the digital signal.

[0068] In some embodiments, since the output of the output pin suddenly changes from 0 to a pulse signal when the leakage current signal is greater than the preset threshold, the client can control the actuating mechanism to perform line disconnection when recognizing the rising edge of the pulse signal. Then, the control circuit 102 locks the output pin to continuously output the pulse signal within a preset time, so that the client has enough time to complete the duty cycle sampling 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 can also first control the output pin to output a high and low level signal to inform the client that a leakage fault has occurred, and then output a pulse signal for a period of time to inform the client of the magnitude of the leakage current signal.

[0069] See Figure 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 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 the magnitude of the total leakage current signal when the magnitude of the total leakage current signal is greater than the first preset threshold. The first output pin is configured to output the first pulse signal. Wherein, the total leakage current signal is the total leakage current signal including an AC component and a DC component.

[0070] The control circuit 102 further includes a second comparison circuit, a second analog-to-digital conversion circuit, and a second output pin connected in sequence. The second comparison circuit is configured to compare the DC 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 DC component of the leakage current signal when the magnitude of the DC component of the leakage current signal is greater than the second preset threshold. The second output pin is configured to output the second pulse signal.

[0071] Thus, according to the first pulse signal, the client can obtain the total AC and DC current value of the leakage current signal. At the same time, according to the second pulse signal, the client can know the magnitude of the DC component of the leakage current signal.

[0072] Taking the first preset threshold as 30 mA as an example, when the magnitude of the AC leakage current signal is greater than 30 mA, the output of the first output pin (i.e., Figure 1 the 30 mA PWM OUT in it) changes suddenly from the 0 level to the PWM signal with the duty cycle corresponding to 30 mA. The frequency of the output PWM signal is, for example, 8 KHz, and the output signal of the first output pin is locked for a certain period of time, for example, 500 ms, to facilitate the client to immediately send a TRIP (tripping) signal when recognizing the presence of the high level, to trip the power supply line within the specified time, and at the same time, there is enough time to complete the duty cycle sampling of the PWM signal to obtain the corresponding AC leakage current value and upload the AC leakage information to a higher-level system.

[0073] Taking the second preset threshold as 6 mA as an example, when the magnitude of the DC component of the leakage current signal is greater than 6 mA, the output of the second output pin (i.e., Figure 1 the 6 mA PWM OUT in it) changes suddenly from the 0 level to the PWM signal with the duty cycle corresponding to 6 mA. The frequency of the output PWM signal is, for example, 8 KHz, and the output signal of the second output pin is locked for a certain period of time, for example, 500 ms, to facilitate the client to immediately send a TRIP signal when recognizing the presence of the high level, to trip the line within the specified time, and at the same time, there is enough time to complete the duty cycle sampling of the PWM signal to obtain the corresponding DC leakage current value and upload the DC leakage information to a higher-level system.

[0074] It should be noted that the values provided above are only examples. The frequency of the PWM signal is not limited to 8K Hz and can be any suitable frequency. Moreover, the frequencies of different PWM signals can be the same or different. In addition, the time for the locked output pin to output the PWM signal is not limited to 500 ms and can also be any suitable time.

[0075] Exemplarily, in addition to the output pin, the control circuit 102 may further include a power supply VCC pin, a GND ground pin, a calibration pin, etc., which will not be described in detail herein.

[0076] In addition to being able to output a pulse signal such as a PWM signal, the output pin of the embodiment of the present invention can also be used to output high and low level signals to represent the type of fault. Specifically, the control circuit 102 further includes: a self-checking circuit for performing system self-checking to obtain a fault status signal, such as ZCT disconnection, short circuit, MCU RAM or Flash error, etc.; and a logic circuit connected to the self-checking circuit for generating a combined signal of high level signals and / or low level signals according to the fault status signal. The logic circuit is also connected to the above at least two output pins for outputting the combined signal through the at least two output pins. Thus, by multiplexing the output pins, the leakage detection device of the embodiment of the present invention can not only output the relevant information of the complete leakage current signal, but also output the information related to the fault status, laying a foundation for the interconnection of the leakage system information. Among them, the embodiment of the present invention does not limit the manner of obtaining the fault status signal, and the fault status signal can be obtained based on any form of self-checking circuit through any form.

[0077] Continuing to refer to Figure 1 , in one embodiment, the control circuit 102 further includes a self-checking instruction input pin (TESTIN) for receiving an external self-checking instruction (such as high and low levels 0 or 1), and the self-checking instruction is used to trigger the self-checking circuit to start performing system self-checking to obtain a fault status signal. In addition to the manner of receiving the self-checking instruction, the system self-checking can also be triggered by other means, such as by the PWM method, periodic self-checking, self-checking when a leakage phenomenon occurs, etc.

[0078] When the output pins include a first output pin and a second output pin, the first output pin can output high and low level signals, and the second output pin can also output high and low level signals. Therefore, four combined signals can be output through the two output pins, and each combined signal can represent one or more types of faults. Refer to Table 1. Since the output pins of the embodiment of the present invention are not limited to two and can also be three or more, when there are N output pins, 2 N types of combined signals can be output.

[0079] Table 1

[0080]

[0081]

[0082] 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 the standby state or the self-check 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 complete short circuit of the turns of the ZCT winding, and so on. Thus, by multiplexing two output pins, multiple system states can be output, and the function mode of pin multiplexing is used to indicate the self-check fault state. Of course, it can be understood that the indication of the working state is not limited to the several types shown in Table 1, and the state represented by each combined signal can be more or less.

[0083] Based on the above description, the leakage detection device according to the embodiment of the present invention is based on at least two comparison circuits, an analog-to-digital conversion circuit, and an output pin, and can output more complete information related to the leakage current signal; at the same time, the fault state information can also be output by multiplexing the output pin.

[0084] Another aspect of the embodiment of the present invention provides a leakage detection device, which includes: a leakage current inductor for sensing a leakage current signal; a control circuit, the control circuit includes: a comparison circuit connected to the leakage current inductor, and the comparison circuit is used to compare the leakage current signal with a preset threshold; an analog-to-digital conversion circuit connected to the comparison circuit, and the analog-to-digital conversion circuit is used to generate a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the preset threshold; an output pin connected to the analog-to-digital conversion circuit for outputting the pulse signal; a self-check circuit for performing system self-check to obtain a fault state signal; a logic circuit connected to the self-check circuit for generating a high level signal or a low level signal according to the fault state signal; the logic circuit is also connected to the output pin for outputting the high level signal or the low level signal through the output pin.

[0085] Different from the leakage detection device described with reference to Figure 1 The leakage detection device of this embodiment only includes one output pin, and this output pin is used to implement two functions. In addition to outputting a pulse signal representing the magnitude of the leakage current based on this output pin, it also outputs a high or low level signal representing the fault state through this output pin, so that the client can timely obtain the leakage information and the fault state. Since the leakage detection device of this embodiment only includes one output pin, this output pin can output two signals, a high level signal and a low level signal, and each signal represents one or more fault states.

[0086] In addition, the leakage current detection device of this embodiment has a lot of the same or similar content as the above-mentioned leakage current detection device. For more details, reference can be made to the relevant descriptions above, which will not be elaborated here.

[0087] Another aspect of the embodiment of the present invention provides a leakage current detection method, which can be implemented by the leakage current detection device described with reference to Figure 1 The following only describes the main steps of the leakage current detection method. For more details, reference can be made to the above.

[0088] Figure 2 FIG. shows a schematic flowchart of a leakage current detection method 200 according to an embodiment of the present invention. As Figure 2 shown, the leakage current detection method 200 of the embodiment of the present invention includes the following steps:

[0089] In step S210, a leakage current signal is acquired, and the leakage current signal is compared with a preset threshold corresponding to the type of the leakage current signal;

[0090] 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 at least a first pulse signal corresponding to a leakage current signal of a first type and a second pulse signal corresponding to a leakage current signal of a second type;

[0091] In step S230, different ones of the pulse signals are output through at least two output pins.

[0092] As described above, in step S210, a leakage current signal can be sensed by a leakage current inductor such as a ZCT, and the leakage current signal can be obtained by detecting the voltage across a sampling resistor. The types of leakage current signals include, but are not limited to, AC signals and DC signals. Exemplarily, the total leakage current signal including an AC component and a DC component can be compared with a first preset threshold through a first comparison circuit, and the DC component can be compared with a second preset threshold through a second comparison circuit.

[0093] In step S220, when the magnitude of the leakage current signal is greater than a preset threshold, a pulse signal is generated according to the magnitude and type of the leakage current signal. The pulse signal includes, but is not limited to, a PWM signal. Specifically, the magnitude of the leakage current signal can be represented by the duty cycle of the PWM signal, and the type of the leakage current signal can be represented by the pin for outputting the PWM signal. Among them, the pulse signal at least includes a first pulse signal corresponding to the leakage current signal of the first type and a second pulse signal corresponding to the leakage current signal of the second type. Exemplarily, the first pulse signal can correspond to the total leakage current signal, and the magnitude of the total leakage current signal can be obtained according to the duty cycle of the first pulse signal; the second pulse signal can correspond to the DC component of the leakage current signal, and the magnitude of the DC component of the leakage current signal can be obtained according to the duty cycle of the second pulse signal.

[0094] It should be noted that the pulse signal is not limited to two pulse signals, and can also include three or more pulse signals, corresponding to different types of leakage current signals respectively.

[0095] After that, in step S230, different pulse signals are output through at least two output pins. For example, the first pulse signal can be output through the first output pin, and the second pulse signal can be output through the second output pin. If more pulse signals are generated, more output pins can be set accordingly. Further, the output pulse signal includes: continuously outputting the pulse signal within a preset time, that is, locking the output pin to continuously output the pulse signal for a period of time, so as to facilitate the client to sample the pulse signal to obtain the magnitude of the leakage current signal.

[0096] In some embodiments, the leakage detection method 200 further includes: performing a system self-check to obtain a fault status signal; generating a combined signal of a high-level signal and / or a low-level signal according to the fault status signal; outputting the combined signal through the at least two output pins. By multiplexing the output pins, not only can the magnitude, type, etc. of the leakage current signal be output, but also the fault status information can be output, so as to facilitate the client to identify the fault type.

[0097] Specifically, after obtaining the fault status signal, based on a preset logic, a high-low level combined signal corresponding to the fault status signal is generated, and each output pin outputs one of a high-level signal and a low-level signal respectively. Two output pins can output four combined signals, and each combined signal represents one or more fault types.

[0098] In one embodiment, the leakage detection method 200 further includes: receiving a self-check instruction and triggering the system self-check according to the self-check instruction. In other embodiments, the system self-check can also be performed when other preset conditions are met, such as performing a system self-check when a leakage occurs, or performing a system self-check regularly, etc.

[0099] The leakage detection method according to the embodiments of the present invention can not only output more complete information related to the leakage current signal, but also output the fault status information by multiplexing the output pins.

[0100] The embodiments of the present invention further provide a charging device, including the leakage detection device as described above and an actuating mechanism connected to the leakage detection device. The actuating structure is configured to disconnect the power supply line when the magnitude of the leakage current signal detected by the leakage detection device is greater than a preset threshold. The charging device according to the embodiments of the present invention can be implemented as a charging pile, a charging gun or other charging devices for charging a vehicle. The leakage detection device can be a board-mounted leakage detection device, which can be directly installed on the PCB board of the charging device. When the charging device charges an electric vehicle, the leakage detection device can be used to detect whether the magnitude of the leakage current during the charging process exceeds the threshold. When the magnitude of the leakage current exceeds the threshold, an alarm is sent to the MCU or other devices on the PCB board to execute the command to stop charging and disconnect the charging line, such as disconnecting a closed relay or circuit breaker mechanism. At the same time, the leakage detection device in the charging device according to the embodiments of the present invention also has the ability to report the magnitude and type of the leakage current signal, as well as the ability to report the self-check result.

[0101] In the specification provided herein, a large number of specific details are set forth. However, it is understood that the embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures and technologies have not been shown in detail so as not to obscure the understanding of this specification.

[0102] Similarly, it should be understood that in order to streamline the present invention and assist in understanding one or more of the various inventive aspects, in the description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present invention should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected by the corresponding claims, the inventive point lies in that the corresponding technical problems can be solved by features less than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the present invention.

[0103] Those skilled in the art will appreciate that, except where features are mutually exclusive, any combination can be employed of all the features disclosed in this specification (including the accompanying claims, abstract and drawings), as well as all the processes or units of any method or apparatus so disclosed. Each feature disclosed in this specification (including the accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

[0104] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not others, combinations of features of different embodiments are meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0105] It should be noted that the above embodiments are illustrative of the present invention rather than limiting thereof, and those skilled in the art can 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 present invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words may be interpreted as names.

[0106] As described above, this is only a specific implementation manner or an illustration of the specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all such changes or substitutions should be covered by 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. A leakage detection device, characterized in that, The leakage detection device includes: A leakage current inductor for sensing a leakage current signal; A control circuit connected to the leakage current inductor, and the control circuit includes: At least two comparison circuits, the comparison circuits are connected to the leakage current inductor and are used to compare the leakage current signal with corresponding preset thresholds. Among them, the at least two comparison circuits include a first comparison circuit and a second comparison circuit. The first comparison circuit is used to compare the leakage current signal with a first preset threshold, and the second comparison circuit is used to compare the DC component of the leakage current signal with a second preset threshold; At least two analog-to-digital conversion circuits, which are connected to the comparison circuits in one-to-one correspondence. The analog-to-digital conversion circuit is used to generate a pulse signal according to the magnitude of the leakage current signal when the magnitude of the leakage current signal is greater than the preset threshold. The at least two analog-to-digital conversion circuits include a first analog-to-digital conversion circuit connected to the first comparison circuit and a second analog-to-digital conversion circuit connected to the second comparison circuit. The first analog-to-digital conversion circuit is used 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 second analog-to-digital conversion circuit is used to generate a second pulse signal according to the magnitude of the DC component of the leakage current signal when the magnitude of the DC component of the leakage current signal is greater than the second preset threshold; At least two output pins, which are connected to the analog-to-digital conversion circuits in one-to-one correspondence and are used to output the pulse signal. The at least two output pins include a first output pin and a second output pin. The first output pin is used to output the first pulse signal, and the second output pin is used to output the second pulse signal.

2. The leakage detection device according to claim 1, wherein The control circuit further includes: A self-checking circuit for performing system self-checking to obtain a fault status signal; A logic circuit connected to the self-checking circuit for generating a combined signal of a high-level signal and / or a low-level signal according to the fault status 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 leakage detection device according to claim 2, characterized in that, The control circuit further includes a self-checking instruction input pin connected to the self-checking circuit for receiving a self-checking instruction, and the self-checking instruction is used to trigger the self-checking circuit to start the system self-checking.

4. The leakage detection device according to claim 1, wherein, The output pin is used to continuously output the pulse signal within a preset time.

5. The leakage detection device according to claim 1, wherein, The analog-to-digital conversion circuit is used to generate a pulse width modulation signal with a corresponding duty cycle according to the magnitude of the leakage current signal.

6. The leakage detection device according to claim 5, characterized in that, The pulse width modulation signals generated by different analog-to-digital conversion circuits have the same or different frequencies.

7. The leakage detection device according to claim 1, wherein, The analog-to-digital conversion circuit is used to generate a frequency modulation signal with a corresponding frequency according to the magnitude of the leakage current signal.

8. The leakage detection device according to claim 1, wherein, The leakage current inductor includes a zero-sequence current transformer.

9. The leakage detection device according to claim 8, characterized in that, It further includes: A sampling resistor 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 an oscillation circuit provided between the zero-sequence current transformer and the control circuit, and the control circuit applies an excitation current to the zero-sequence current transformer through the oscillation circuit.

10. A leakage detection method, characterized in that, The method is used for the leakage detection device according to any one of claims 1-9, and the method includes: Obtaining a leakage current signal, and comparing the leakage current signal with a preset threshold corresponding to the type of the leakage current signal, wherein, comparing the leakage current signal with a first preset threshold, and comparing the DC component of the leakage current signal with a second preset threshold; when the magnitude of the leakage current signal is greater than the preset threshold, generating a pulse signal according to the magnitude and type of the leakage current signal, wherein 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, generating the 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 generating a second pulse signal according to the magnitude of the DC component of the leakage current signal when the magnitude of the DC component of the leakage current signal is greater than the second preset threshold; Outputting different ones of the pulse signals through at least two output pins respectively.

11. The leakage detection method according to claim 10, wherein, It further includes: Performing a system self-check to obtain a fault status signal; Generating a combined signal of a high-level signal and / or a low-level signal according to the fault status signal; Outputting the combined signal through the at least two output pins.

12. The leakage detection method according to claim 10, wherein Outputting the pulse signal includes: Continuously outputting the pulse signal within a preset time.

13. A charging device, characterized in that, The charging device includes: The leakage detection device according to any one of claims 1 to 9; And an actuating mechanism connected to the leakage detection device for disconnecting the power supply line when the leakage detection device detects that the magnitude of the leakage current signal is greater than the preset threshold.

Images