Charging pile electric leakage detection method and electronic equipment

Abstract

The application is suitable for the technical field of charging piles, and provides a charging pile electric leakage detection method and an electronic device.The method comprises the following steps: based on an induced current module, collecting the current flowing through the ground wire of a charging pile and outputting an induced current; the induced current module is coupled to the ground wire of the charging pile; based on a filtering module, filtering the induced current and converting the induced current into a voltage signal; the filtering module is connected with the induced current module; based on a detection module, receiving the voltage signal and outputting an alarm signal based on a target time length of receiving the voltage signal, a voltage value of the voltage signal and a target alarm parameter; the method can solve the problem that during the detection of electric leakage on the charging pile, there is an interference current flowing into the PE line through the Y capacitor at the moment when the relay is closed, and due to different distribution parameters, oscillation is generated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of charging piles, and particularly relates to a charging pile electric leakage detection method and an electronic device. BACKGROUND

[0002] RCD (Residual Current Device) is a kind of electric leakage protection device. The existing AC charging piles in China all have on-board RCDs, but they can only protect against electric leakage in the charging pile. When the PE line in the charging pile is broken, the electric leakage of the external equipment of the charging pile leaks to the charging pile through the PE (ground) line, and then leaks to the vehicle end through the gun line of the charging pile, which may cause electric shock when a person touches the vehicle. Therefore, it is necessary to detect the electric leakage on the PE line in the charging pile.

[0003] However, in the existing charging pile electric leakage detection method, false positives may occur when the current signal is oscillating or there is interference on the PE line. SUMMARY

[0004] The purpose of the present application is to provide a charging pile electric leakage detection method and an electronic device to solve the problem that in the prior art method for detecting electric leakage on a charging pile, there is interference current flowing into the PE line through the Y capacitor at the moment when the relay is closed, and due to different distribution parameters, oscillation occurs.

[0005] In a first aspect, the embodiments of the present application provide a charging pile electric leakage detection method, which comprises:

[0006] Based on the induced current module, the current flowing through the ground line of the charging pile is collected, and an induced current is output; the induced current module is coupled to the ground line of the charging pile;

[0007] Based on the filtering module, the induced current is filtered and converted into a voltage signal; the filtering module is connected to the induced current module;

[0008] Based on the detection module, the voltage signal is received, and based on the target time length of receiving the voltage signal, the voltage value of the voltage signal, and the target alarm parameter, an alarm signal is output.

[0009] In one of the embodiments, the output of the alarm signal based on the target time length, the voltage value of the voltage signal, and the target alarm parameter comprises:

[0010] When the target time length is greater than the preset time length, it is determined whether the voltage value of the voltage signal exceeds a voltage threshold value, and if it exceeds the voltage threshold value, the alarm signal is output according to the comparison result of the target alarm parameter and the preset threshold value.

[0011] In one of the embodiments, before outputting the alarm signal according to the comparison result of the target alarm parameter and the preset threshold, the method further comprises:

[0012] increasing the alarm parameter by a preset second count to obtain the target alarm parameter;

[0013] outputting the alarm signal according to the comparison result of the target alarm parameter and the preset threshold, comprising:

[0014] if the target alarm parameter exceeds the preset threshold, outputting the alarm signal;

[0015] if the target alarm parameter is less than the preset threshold, continuing to execute the step of collecting the current flowing through the ground wire of the charging pile based on the current sensing module and subsequent steps.

[0016] In one of the embodiments, the current sensing module comprises a current transformer, a common mode inductor, a first resistor and a second resistor.

[0017] The first output end and the second output end of the current transformer are connected to the first input end and the second input end of the common mode inductor, respectively.

[0018] The first output end of the common mode inductor is connected to the second end of the first resistor, and the second output end is connected to the first end of the second resistor, for filtering the common mode interference signal of the port.

[0019] The first end of the first resistor is connected to the second end of the second resistor, and the second end is also connected to the first input end of the filtering module.

[0020] The first end of the second resistor is also connected to the second input end of the filtering module.

[0021] The first end of the first resistor and the second end of the second resistor are grounded.

[0022] In one of the embodiments, the filtering module comprises a first filtering module, a differential amplification module and a second filtering module.

[0023] The first output end and the second output end of the first filtering module are connected to the first input end and the second input end of the differential amplification module, respectively, and the first filtering module is used for filtering the common mode interference signal.

[0024] The output end of the differential amplification module is connected to the input end of the second filtering module, and the differential amplification module is used for amplifying the voltage signal output by the first filtering module.

[0025] The output end of the second filtering module is connected to the detection module, and the second filtering module is used for filtering the common mode interference signal.

[0026] In one of the embodiments, the first filter module comprises a third resistor, a fourth resistor, a first capacitor, and a second capacitor.

[0027] A first end of the third resistor is connected to a first end of the first capacitor and a first input end of the differential amplifier module, and a second end of the third resistor is connected to a second end of the first resistor and a first output end of the common-mode inductor.

[0028] A first end of the fourth resistor is connected to a first end of the second capacitor and a second input end of the differential amplifier module, and a second end of the fourth resistor is connected to a first end of the second resistor, and a second end of the first capacitor is connected to a second end of the second capacitor.

[0029] In one of the embodiments, the differential amplifier module comprises an input impedance matching unit, a decoupling unit, and a first operational amplifier unit.

[0030] A first input end and a second input end of the input impedance matching unit are connected to a first output end and a second output end of the first filter module, respectively, and a first output end and a second output end of the input impedance matching unit are connected to a first input end and a second input end of the decoupling unit, respectively.

[0031] A first output end and a second output end of the decoupling unit are connected to an inverting input end and a non-inverting input end of the first operational amplifier unit, respectively.

[0032] An output end of the first operational amplifier unit is connected to an input end of the second filter module.

[0033] In one of the embodiments, the second filter module comprises a first filter circuit, a second operational amplifier unit, and a second filter circuit.

[0034] The first filter circuit is connected to the second operational amplifier unit and is configured to filter out common-mode interference signals.

[0035] The second operational amplifier unit is connected to the second filter circuit and is configured to follow the voltage signal.

[0036] The second filter circuit is connected to the detection module and is configured to filter out common-mode interference signals.

[0037] The first filter circuit comprises a fifth resistor and a third capacitor.

[0038] A first end of the fifth resistor is connected to an output end of the first operational amplifier unit, and a second end of the fifth resistor is connected to a second end of the third capacitor and a non-inverting input end of the second operational amplifier unit.

[0039] The first end of the third capacitor is grounded.

[0040] The second filter circuit comprises a sixth resistor and a fourth capacitor.

[0041] The first end of the sixth resistor is connected to the inverting input end and the output end of the second operational amplifier unit, and the second end of the sixth resistor is connected to the second end of the fourth capacitor and the input end of the detection module.

[0042] The first end of the fourth capacitor is grounded.

[0043] In one of the embodiments, the method comprises:

[0044] Obtaining a closing signal of a relay;

[0045] Determining the target duration based on the closing signal of the relay.

[0046] In a second aspect, the embodiments of the present application provide an electronic device, comprising a leakage detection circuit, the leakage detection circuit comprising a current sensing module, a filter module and a detection module, and the leakage detection circuit performs the method of the first aspect when working.

[0047] In a third aspect, the embodiments of the present application provide a leakage detection device for a charging pile, comprising:

[0048] A sensing unit is configured to acquire a current flowing through a ground wire of the charging pile based on a sensing current module, and output a sensing current; the sensing current module is coupled to the ground wire of the charging pile;

[0049] A filtering unit is configured to filter the sensing current based on a filter module, and convert the sensing current into a voltage signal; the filter module is connected to the sensing current module;

[0050] An output unit is configured to receive the voltage signal based on a detection module, and output an alarm signal based on a target duration of receiving the voltage signal, a voltage value of the voltage signal and a target alarm parameter.

[0051] It can be understood that the beneficial effects of the second aspect and the third aspect described above can be referred to the related description in the first aspect, and will not be repeated here.

[0052] Compared with the prior art, the application has the beneficial effects that: through the charging pile electric leakage detection method provided by the application, the current flowing through the ground wire of the charging pile is collected based on an induced current module, and an induced current is output; based on a filtering module, the induced current is filtered and converted into a voltage signal; based on a detection module, the voltage signal is received, and based on a target time length of receiving the voltage signal, a voltage value of the voltage signal and a target alarm parameter, an alarm signal is output; in the process of detecting electric leakage on the charging pile, the relay is closed at the moment, and there will be an interference current flowing through the Y capacitor into the PE line, and due to different distribution parameters, oscillation will be generated. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0054] Figure 1 is one of the charging pile electric leakage detection circuit schematic diagrams provided by the embodiments of the application;

[0055] Figure 2 is a general implementation flow schematic diagram of the charging pile electric leakage detection method provided by the embodiments of the application;

[0056] Figure 3 is a structure schematic diagram of the filtering module provided by the embodiments of the application.

[0057] Figure 4 is a second charging pile electric leakage detection circuit schematic diagram provided by the embodiments of the application;

[0058] Figure 5 is a specific implementation flow schematic diagram of the charging pile electric leakage detection method provided by the embodiments of the application;

[0059] Figure 6 is a structure schematic diagram of the charging device provided by the embodiments of the application;

[0060] Figure 7 is a structure schematic diagram of the charging pile electric leakage detection device provided by the embodiments of the application.

[0061] The following explains the reference signs:

[0062] 100: charging pile electric leakage detection circuit; 110: current sensing module; 120: filtering module; 130: detection module; 122: first filtering module; 124: differential amplification module; 126: second filtering module; 1242: input impedance matching unit; 1244: decoupling unit; 1246: first operational amplifier unit; 1262: first filtering circuit; 1264: second filtering circuit;

[0063] J1: current transformer; L1: common mode inductor; R1: first resistor; R2: second resistor; R3: third resistor; R4: fourth resistor; R5: fifth resistor; R6: sixth resistor; R7: seventh resistor; R8: eighth resistor; R9: ninth resistor; R10: tenth resistor; C1: first capacitor; C2: second capacitor; C3: third capacitor; C4: fourth capacitor; C5: fifth capacitor; C6: sixth capacitor; C7: seventh capacitor; REF: bias voltage; V: power input terminal; U1: first operational amplifier; U2: second operational amplifier unit; PE_AD: output signal. DETAILED DESCRIPTION

[0064] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0065] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0066] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0067] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0068] In this application, unless otherwise clearly indicated or limited by context, the terms "mount", "connect", "connection", "fixed", "fixedly connected" and like terms are to be construed broadly, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, or electrical connection or can be communication with each other; can be direct connection, or indirect connection through intermediate medium; can be internal connection of two elements, or interaction between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0069] In this application, unless otherwise clearly indicated or limited by context, the terms "mount", "connect", "connection", "fixed", "fixedly connected" and like terms are to be construed broadly, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, or electrical connection or can be communication with each other; can be direct connection, or indirect connection through intermediate medium; can be internal connection of two elements, or interaction between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0070] Finally, it should also be noted that the terms "comprising", "containing" or any other variant are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or terminal device, and does not exclude the presence of other same elements in the process, method, article or terminal device including the elements.

[0071] The existing AC charging pile in China has a built-in RCD (Residual Current Device), but it can only protect against leakage in the AC charging pile. When the PE line in the AC charging pile is broken, the leakage of the external equipment of the charging pile (other electrical appliances connected in parallel with the AC charging pile) leaks to the AC charging pile through the PE line, and then leaks to the vehicle end through the gun line of the AC charging pile, which poses a risk of electric shock when a person touches the vehicle.

[0072] In order to solve the above problems, it is necessary to detect the leakage on the PE line in the alternating current charging pile, but because the Y capacitor in the alternating current charging pile and the vehicle end BMS (Battery Management System) is connected to the PE line, the Y capacitor will be charged at the moment of charging, at this time the current flowing into the PE line is much larger than the current of the PE line leakage, and due to the existence of the board level distribution inductance, the current signal will oscillate, which will cause false alarm of the leakage detection, and when there is interference on the PE line, it will also cause false alarm.

[0073] In view of the above defects, the embodiment of the application provides a charging pile leakage detection method, a filter circuit is arranged on a hardware circuit to filter out common mode interference signals caused by PCB (Printed Circuit Board) wiring and parasitic parameters; a delay alarm is set in the software, whether the voltage signal exceeds the voltage threshold is judged after a preset time length from receiving the voltage signal, so as to avoid the transient interference in the initial stage of voltage signal transmission; if the voltage threshold is exceeded, an alarm signal is output according to the comparison result of the alarm second count and the preset threshold; so as to solve the problem of false alarm when the signal oscillates or there is interference on the PE line in the process of detecting the leakage on the PE line of the alternating current charging pile.

[0074] Firstly, some professional terms involved in the application are explained and described:

[0075] RCD (Residual Current Device) is the English abbreviation of residual current device, which is a leakage protection device, that is, under normal working conditions, the load is turned on and the current is turned off, and when the residual current of the circuit reaches the specified value under the specified conditions, the contact is actuated to disconnect the main circuit. A protector, the residual current device may be a combination of various elements for detecting residual current and turning on and off the main circuit current. The leakage protection device is a low-voltage safety protection appliance, which has the following functions: first, it is used to prevent single-phase electric shock accidents caused by leakage; second, it is used to prevent fire and equipment burning accidents caused by leakage; third, it is used to detect and cut off various single-phase ground faults; fourth, some leakage protection devices can also be used for overload, overvoltage, undervoltage and open-phase protection.

[0076] PE refers to the grounding wire of the charging pile, which is used to protect equipment and people when leakage occurs. According to the national standard, no PE line is not allowed to charge.

[0077] BMS (Battery Management System) refers to the battery management system.

[0078] Safety capacitor refers to the capacitor used in the following occasions, that is, the capacitor will not cause electric shock and endanger personal safety after failure. It includes two types of X capacitor and Y capacitor. X capacitor is the capacitor connected across the two lines of power line (L-N), and is generally selected from metal film capacitor. Y capacitor is the capacitor connected across the two lines of power line and ground (L-E, N-E) respectively, and is generally in pairs. Based on the limitation of leakage current, the value of Y capacitor cannot be too large, and the value of X capacitor is generally uF level and the value of Y capacitor is nF level. X capacitor suppresses differential mode interference, and Y capacitor suppresses common mode interference.

[0079] PCB, the Chinese name of which is printed circuit board, is also called printed wiring board. It is an important electronic component, a support for electronic components, and a carrier for electrical interconnection of electronic components. Since it is made by electronic printing, it is called "printed" circuit board.

[0080] There are mainly three kinds of parasitic parameters: parasitic capacitance, parasitic resistance and parasitic inductance. Parasitic capacitance generally refers to the capacitance characteristics of inductance, resistance, chip pins and the like under high frequency conditions. In fact, a resistor is equivalent to a capacitor, an inductor and a resistor in series, which is not very obvious under low frequency conditions, but the equivalent value will increase under high frequency conditions, which should be considered in calculation and cannot be ignored. ESL is the equivalent inductance, and ESR is the equivalent resistance. Whether it is resistance, capacitance, inductance, or diode, triode, MOS tube, IC, we should consider their equivalent capacitance value and inductance value under high frequency conditions.

[0081] According to an aspect of the embodiments of the present application, a charging pile leakage detection circuit 100 is provided.

[0082] As shown in the figure, the charging pile leakage detection circuit 100 includes a current sensing module 110, a filtering module 120 and a detection module 130. Figure 1

[0083] The current sensing module 110 is coupled to the PE line of the AC charging pile, used for sensing the current flowing through the PE line and outputting a sensing current, which is a differential current signal.

[0084] The filtering module 120 is connected with the current sensing module 110, used for filtering the sensing current and converting it into a voltage signal, which is the voltage signal PE_AD finally output by the hardware circuit.

[0085] The detection module 130 is connected with the filtering module 120, used for receiving the voltage signal and judging whether the voltage signal exceeds a voltage threshold after a preset time period from receiving the voltage signal. If the voltage signal exceeds the voltage threshold, an alarm signal is output according to the comparison result of the alarm second count and the preset threshold. ​

[0086] The current sensing module 110 is coupled to the PE line of the alternating current charging pile, which means that the current sensing module 110 is directly sleeved on the PE line of the alternating current charging pile.

[0087] The filtering module 120 filters the common-mode interference signal of the port and the common-mode interference signal caused by the PCB wiring and parasitic parameters.

[0088] When the current signal is converted into a voltage signal, only a resistance with a certain resistance value needs to be connected in series at the current output end. When the induced current signal is converted into a voltage signal, a resistance with a certain resistance value is connected in series at the first output end and the second output end of the common-mode inductor.

[0089] In addition, the reason for setting the delay is that the Y capacitor of different alternating current charging piles or vehicle-mounted BMSs has different sizes, and the distribution inductance has uncertain sizes. The actual interference oscillation time is different from a few milliseconds to a few hundred milliseconds. In order to avoid instantaneous interference as much as possible, the preset time length corresponds to the time from power-on to voltage signal stabilization (for example, the time of relay closure). Preferably, the preset time length is set to 1 second, that is, the delay is set to 1 second.

[0090] It should be noted that the delay alarm judgment means that after the preset time length from receiving the voltage signal, it is judged whether the voltage signal exceeds the voltage threshold. If the voltage threshold is exceeded, the alarm signal is output according to the comparison result of the alarm second count and the preset threshold. When the voltage signal exceeds the voltage threshold, alarm processing will not be performed immediately, and it is also necessary to judge whether the alarm second count reaches the preset threshold. Alarm processing is performed only after the alarm second count reaches the preset threshold, and the alarm signal is output.

[0091] The embodiment can solve the problem of false alarm when the signal oscillates or there is interference on the PE line during detection of leakage on the PE line of the alternating current charging pile.

[0092] Based on the above embodiment, in order to solve the problem of false alarm when the current signal oscillates or there is interference on the PE line in the method for detecting leakage on the PE line of the alternating current charging pile in the prior art, the present embodiment provides a charging pile leakage detection method, which is specifically described with reference to Figure 2 , Figure 2 The overall implementation flowchart of the charging pile leakage detection method provided by the embodiment of the present application includes the following steps:

[0093] S201, based on the induced current module, the current flowing through the ground wire of the charging pile is collected, and the induced current is output. The induced current module is coupled to the ground wire of the charging pile.

[0094] In some embodiments, based on the current sensing module 110, the current flowing through the PE line of the alternating current charging pile is sensed to obtain an induced current, and the induced current is a differential current signal.

[0095] For example, the current sensing module 110 is coupled to the ground wire of the alternating current charging pile, senses the current flowing through the PE wire of the alternating current charging pile, and outputs the sensed current.

[0096] In S202, the sensed current is filtered based on the filtering module, and converted into a voltage signal; the filtering module is connected to the current sensing module.

[0097] In some embodiments, when the sensed current is filtered based on the filtering module 120 and converted into a voltage signal, the converted voltage signal may be small, so the converted voltage signal needs to be amplified.

[0098] In S203, the voltage signal is received based on the detection module, and an alarm signal is output based on the target duration of receiving the voltage signal, the voltage value of the voltage signal, and the target alarm parameter.

[0099] In some embodiments, when the target duration of receiving the voltage signal is greater than the preset duration, it is determined whether the voltage value of the voltage signal exceeds the voltage threshold value, and if it exceeds the voltage threshold value, an alarm signal is output according to the comparison result of the target alarm parameter and the preset threshold value.

[0100] It should be noted that in the delay judgment, the lengthened time needs to be determined according to the size of the Y capacitor and the distributed inductance of different vehicle BMS; in the alarm judgment, when the voltage value of the voltage signal just exceeds the voltage threshold value, alarm processing will not be performed immediately, but it needs to be judged whether the target alarm parameter reaches the preset threshold value, and alarm processing is performed after the target alarm parameter reaches the preset threshold value, and the alarm signal is output.

[0101] For example, before the alarm signal is output according to the comparison result of the target alarm parameter and the preset threshold value, it further includes: increasing the alarm parameter by a preset second count to obtain the target alarm parameter. According to the comparison result of the target alarm parameter and the preset threshold value, the alarm signal is output, including: if the target alarm parameter exceeds the preset threshold value, the alarm signal is output; if the target alarm parameter is less than the preset threshold value, the step of collecting the current flowing through the ground wire of the charging pile based on the current sensing module and the subsequent steps are continued.

[0102] Among them, the alarm parameter refers to the value generated by the program internal time counter when judging whether to output an alarm signal, such as alarm second count; the target alarm parameter refers to the value generated by the program internal time counter after the alarm parameter gradually increases with the increase of the program polling time when the program is polled, such as the alarm second count after increasing a preset second count or multiple times.

[0103] In some embodiments, the method for determining the target duration of receiving the voltage signal is: first, obtaining the closing signal of the relay; second, based on the closing signal of the relay, when the relay closing duration is less than the preset duration, increasing the relay closing duration by the preset time count.

[0104] Through the embodiment, the overcurrent false alarm on the AC charging pile PE line caused by the instantaneous charging of the Y capacitor at the moment of relay closing can be effectively prevented, and the false alarm rate is greatly reduced through the cooperation of software and hardware.

[0105] Specifically, as shown in Figure 4 , the current sensing module 110 includes a current transformer J1, a common mode inductor L1, a first resistor R1, and a second resistor R2.

[0106] The first output end and the second output end of the current transformer J1 are connected to the first input end and the second input end of the common mode inductor L1, respectively. The current transformer J1 outputs a differential current signal.

[0107] The first output end of the common mode inductor L1 is connected to the second end of the first resistor R1, and the second output end is connected to the first end of the second resistor R2. The common mode inductor L1 filters the common mode interference signal at the port.

[0108] The first end of the first resistor R1 is connected to the second end of the second resistor R2, and the second end is also connected to the first input end of the filtering module 120.

[0109] The first end of the second resistor R2 is also connected to the second input end of the filtering module 120.

[0110] The first end of the first resistor R1 and the second end of the second resistor R2 are grounded.

[0111] The first resistor R1 and the second resistor R2 are sampling resistors, which are used to convert the differential current signal into a smaller differential voltage signal.

[0112] First, the current transformer J1 coupled to the AC charging pile PE line senses the current flowing through the PE line and outputs the sensed current, wherein the sensed current is a differential current signal; second, the common mode inductor L1 filters the common mode interference signal at the port; finally, the first resistor R1 and the second resistor R2 convert the differential current signal into a smaller differential voltage signal. The current transformer J1 is used for current sampling, which is convenient and simple.

[0113] As shown in Figure 3 and Figure 4 , the filtering module 120 includes a first filtering module 122, a differential amplification module 124, and a second filtering module 126.

[0114] The first output end and the second output end of the first filter module 122 are connected with the first input end and the second input end of the differential amplification module 124 respectively, the first filter module 122 is an RC low-pass filter circuit, is placed beside the sampling port of the single-chip microcomputer, is used for outputting a smaller differential voltage signal, and filtering out a common-mode interference signal caused by PCB wiring and parasitic parameters.

[0115] The output end of the differential amplification module 124 is connected with the input end of the second filter module 126, for amplifying the smaller differential voltage signal output by the first filter module 122.

[0116] The output end of the second filter module 126 is connected with the detection module 130, for further filtering out the common-mode interference signal.

[0117] Firstly, the first filter module 122 receives the smaller differential voltage signal output by the current sensing module 110, filters out the common-mode interference signal caused by PCB wiring and parasitic parameters, then transmits the smaller differential voltage signal after filtering out the interference signal to the differential amplification module 124; secondly, the differential amplification module 124 receives the smaller differential voltage signal after filtering out the interference signal output by the first filter module 122, amplifies the smaller differential voltage signal, then transmits the differential voltage signal after amplification to the second filter module 126; finally, the second filter module 126 receives the larger differential voltage signal output by the differential amplification module 124, further filters out the common-mode interference signal, then transmits the larger differential voltage signal after filtering out the common-mode interference signal to the detection module 130.

[0118] The first filter module 122 can filter out the common-mode interference signal caused by PCB wiring and parasitic parameters; the differential amplification module 124 can amplify the smaller differential voltage signal; the second filter module 126 can further filter out the common-mode interference signal, so that the signal obtained by sampling is accurate and can be recognized by the detection module 130.

[0119] As shown in Figure 4 The first filter module 122 comprises a third resistor R3, a fourth resistor R4, a first capacitor C1 and a second capacitor C2.

[0120] The first end of the third resistor R3 is connected with the first end of the first capacitor C1 and the first input end of the differential amplification module 124, and the second end of the third resistor R3 is connected with the second end of the first resistor R1 and the first output end of the common-mode inductor L1.

[0121] The first end of the fourth resistor R4 is connected with the first end of the second capacitor C2 and the second input end of the differential amplification module 124, and the second end of the fourth resistor R4 is connected with the first end of the second resistor R2. Meanwhile, the second end of the first capacitor C1 and the second end of the second capacitor C2 are grounded, so as to provide a common reference point for the first capacitor C1 and the second capacitor C2, thereby achieving better anti-interference effect.

[0122] The third resistor R3 and the fourth resistor R4 limit the charging and discharging speed of the first capacitor C1 and the second capacitor C2, so that the voltage tends to be gentle, and the first capacitor C1 and the second capacitor C2 are filter capacitors; finally, the smaller differential voltage signal after filtering the common-mode interference signal is transmitted to the differential amplification module 124.

[0123] The first filter module 122 is an RC low-pass filter circuit, which can transmit low-frequency signals to the output end with less loss and effectively suppress high-frequency signals. The first filter module 122 is placed beside the sampling port of the single-chip microcomputer, and can filter the common-mode interference signal caused by PCB wiring and parasitic parameters.

[0124] As shown in Figure 3 , the differential amplification module 124 includes: an input impedance matching unit 1242, a decoupling unit 1244, and a first operational amplifier unit 1246.

[0125] The first input end and the second input end of the input impedance matching unit 1242 are connected with the first output end and the second output end of the first filter module 122 respectively, and the first output end and the second output end of the input impedance matching unit 1242 are connected with the first input end and the second input end of the decoupling unit 1244 respectively.

[0126] The first output end and the second output end of the decoupling unit 1244 are connected with the inverting input end and the non-inverting input end of the first operational amplifier unit 1246 respectively.

[0127] The output end of the first operational amplifier unit 1246 is connected with the input end of the second filter module 126.

[0128] The input impedance matching unit 1242 functions to match input impedance, form a dislocation voltage, and reduce dislocation voltage caused by input bias current. The decoupling unit 1244 functions to reduce source impedance, reduce power supply noise, and increase operational amplifier stability. The first operational amplifier unit 1246 functions to amplify the smaller differential voltage signal output by the first filter module 122.

[0129] As shown in Figure 4 , the input impedance matching unit 1242 includes: a seventh resistor R7, an eighth resistor R8.

[0130] The first end of the seventh resistor R7 is connected with the first output end of the first filter module 122, and the second end of the seventh resistor R7 is connected with the first input end of the decoupling unit 1244.

[0131] The first end of the eighth resistor R8 is connected with the second output end of the first filter module 122, and the second end of the eighth resistor R8 is connected with the second input end of the decoupling unit 1244.

[0132] The resistance values of the seventh resistor R7 and the eighth resistor R8 are the same, the non-inverting and inverting input ends of the first operational amplifier U1 are connected with resistors with the same resistance value, which is to match the input impedance, and the two resistors with the same resistance value form the same size and opposite direction offset voltage, thereby reducing the offset voltage caused by the input bias current.

[0133] As shown in Figure 4 The decoupling unit 1244 includes a fifth capacitor C5, a sixth capacitor C6, a ninth resistor R9, a tenth resistor R10 and a bias voltage REF.

[0134] The first end of the fifth capacitor C5 is connected with the second end of the seventh resistor R7, the first end of the ninth resistor R9 and the inverting input end of the first operational amplifier U1, and the second end of the fifth capacitor C5 is connected with the second end of the ninth resistor R9, the output end of the first operational amplifier U1 and the input end of the second filter module 126.

[0135] The first end of the sixth capacitor C6 is connected with the first end of the tenth resistor R10, the non-inverting input end of the first operational amplifier U1 and the second end of the eighth resistor R8, and the second end of the sixth capacitor C6 is connected with the second end of the tenth resistor R10 and the bias voltage REF.

[0136] The fifth capacitor C5 and the ninth resistor R9 are connected in parallel with the first operational amplifier U1, and the sixth capacitor C6 and the tenth resistor R10 are connected in parallel and connected to the non-inverting input end of the first operational amplifier U1. The operational amplifier generally adds a capacitor to the non-inverting and inverting input ends, which is called a decoupling capacitor, and functions to reduce the source impedance, reduce the power supply noise and increase the operational stability. The capacitance value is generally 104(0.1 μF), which can be reduced according to the increase of the working frequency. The resistance value of the ninth resistor R9 is generally about 100K. The ninth resistor R9 provides a small DC feedback loop for the offset voltage of the first operational amplifier U1, so that the offset voltage is not obvious on the output, thereby making the output triangular wave meet the design requirements. The tenth resistor R10 is a load, which functions to match the input impedance, reduce the offset voltage caused by the input bias current, and increase the charge and discharge time constant of the sixth capacitor C6.

[0137] The bias voltage REF is a voltage connected to the non-inverting input terminal of the first operational amplifier U1 through the sixth capacitor C6, which is a positive voltage, and functions to ensure that the output signal is a positive voltage signal. Preferably, the bias voltage is a positive voltage of 1.5 V.

[0138] As shown in Figure 4 The first operational amplifier unit 1246 includes a first operational amplifier U1, a seventh capacitor C7, and a power input terminal V.

[0139] The non-inverting input terminal of the first operational amplifier U1 is connected to the second output terminal of the decoupling unit 1244, the inverting input terminal of the first operational amplifier U1 is connected to the first output terminal of the decoupling unit 1244, and the output terminal of the first operational amplifier U1 is connected to the input terminal of the second filter module 126.

[0140] The first end of the seventh capacitor C7 is connected to the inverting input terminal of the first operational amplifier U1 and the power input terminal V, and the second end of the seventh capacitor C7 is grounded. The seventh capacitor C7 is a power filter capacitor of the first operational amplifier U1, which makes the ripple of the operational amplifier output signal smaller and the sampling more accurate.

[0141] The seventh capacitor C7 is a power filter capacitor of the first operational amplifier U1, which makes the ripple of the operational amplifier output signal smaller and the sampling more accurate. The first operational amplifier U1 functions to amplify the small differential voltage signal after the common-mode interference signal is filtered out by the first filter module 122, and transmit the large differential voltage signal after amplification to the second filter module 126. The power input terminal V is connected to the power supply to supply power to the first operational amplifier U1 and charge the seventh capacitor C7.

[0142] As shown in Figure 3 and Figure 4 The second filter module 126 includes a first filter circuit 1262, a second operational amplifier unit U2, and a second filter circuit 1264.

[0143] The first filter circuit 1262 is connected to the second operational amplifier unit U2 and is used to further filter out common-mode interference signals.

[0144] The second operational amplifier unit U2 is connected to the second filter circuit 1264 and is used to follow the voltage signal and prevent interference. The second operational amplifier unit U2 can be an operational amplifier.

[0145] The second filter circuit 1264 is connected to the detection module 130 and is an RC low-pass filter circuit, which is used to further filter out common-mode interference signals.

[0146] As shown in Figure 4 The first filter circuit 1262 includes a fifth resistor R5 and a third capacitor C3.

[0147] The first end of the fifth resistor R5 is connected with the output end of the first operational amplifier U1, the second end of the third capacitor C3 and the second end of the seventh resistor R7, and the second end of the fifth resistor R5 is connected with the second end of the third capacitor C3 and the first end of the second operational amplifier unit U2.

[0148] The first end of the third capacitor C3 is grounded.

[0149] As shown in Figure 4 The second filter circuit 1264 includes a sixth resistor R6 and a fourth capacitor C4.

[0150] The first end of the sixth resistor R6 is connected with the inverting input end and the output end of the second operational amplifier unit U2, and the second end of the sixth resistor R6 is connected with the second end of the fourth capacitor C4 and the input end of the detection module 130.

[0151] The first end of the fourth capacitor C4 is grounded.

[0152] Preferably, in the present application, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6 and the seventh capacitor C7 are three-terminal capacitors. The high-frequency equivalent inductance of the three-terminal capacitor is lower than that of the ordinary capacitor, which ensures the suppression ability of high-frequency electromagnetic interference.

[0153] Preferably, the common-mode inductor L1 in the present application adopts DMR40 material, and the magnetic core of the material has good frequency characteristics and temperature characteristics.

[0154] The charging pile leakage detection circuit 100 provided by the present application filters out common-mode interference signals through two-stage filter circuits to realize wideband filtering.

[0155] Finally, it should be noted that the resistance value, capacitance value and inductance value of the resistors, capacitors and inductors involved in the embodiments of the present application can be selected according to actual needs, and the embodiments of the present application do not limit this.

[0156] Please refer to Figure 5 , Figure 5 is a flow diagram of the specific implementation of the charging pile leakage detection method provided by the embodiments of the present application. As Figure 5 shown, the method can include the following steps:

[0157] Firstly, the current flowing through the ground wire of the charging pile is sampled to obtain an induced current, and the induced current is a differential current signal.

[0158] Secondly, the differential current signal is converted into a smaller differential voltage signal.

[0159] The third step is to filter out common-mode interference signals caused by PCB traces and parasitic parameters.

[0160] The fourth step is to amplify the smaller differential voltage signal.

[0161] The fifth step is to further filter out common-mode interference signals.

[0162] The sixth step is to track the signal to prevent interference.

[0163] Step 7: Further filter out common-mode interference signals.

[0164] In some embodiments, the operations in steps one through seven above do not need to be reflected in the computer program corresponding to the method provided in this application embodiment. Only the operations in the subsequent steps need to be performed. This is because the delay alarm judgment in the subsequent steps is very fast in actual program operation. It may run a complete program once every few milliseconds. If the operations in steps one through seven above are added, it will affect the operation of the entire delay alarm judgment program. Therefore, it does not need to be reflected in the computer program corresponding to the above method.

[0165] For example, such as Figure 5 As shown in the flowchart illustrating the specific implementation of the method provided in this application embodiment, the operations in steps one through seven described above are not illustrated.

[0166] Step 8: The microcontroller samples the output signal PE_AD.

[0167] Step 9: The microcontroller filters the output signal PE_AD.

[0168] Step 10: Determine whether the charging permission flag is set. If the charging permission flag is set, determine whether the relay closing flag is set. If the charging permission flag is cleared, determine whether the sampled filter value exceeds the voltage threshold.

[0169] The tenth step is that if the charging permission flag is set, it is judged whether the relay closing flag is set or not. If the relay closing flag is set, it is judged whether the relay closing preset time flag is set or not. If the relay closing preset time flag is set, it is judged whether the sampling filtered value exceeds the voltage threshold value. If the sampling filtered value exceeds the voltage threshold value, the alarm second count is increased by the preset second count. When the alarm second count is greater than or equal to the preset threshold value, the alarm processing is performed. After the alarm processing is completed, the alarm second count is cleared, and the sampling and filtering are continued. When the alarm second count is less than the preset threshold value, the sampling and filtering are continued. If the sampling filtered value does not exceed the voltage threshold value, the alarm second count is cleared, and the sampling and filtering are continued. If the relay closing preset time flag is cleared, the relay closing time count is increased by the preset time count. It is judged whether the relay closing time count after the preset count is increased is greater than the preset time of the relay closing. If it is greater than or equal to, the relay closing preset time flag is set, and the relay closing time count is cleared. Then, the above alarm judgment is performed. If it is less than, the sampling and filtering are performed. If the relay closing flag is cleared, the relay is closed, the relay closing flag is set, and the sampling and filtering are performed.

[0170] In some embodiments, because the Y capacitor size of different vehicle BMSs is different, and the distribution inductance size is uncertain, the actual interference oscillation time is between several milliseconds and several hundred milliseconds. In order to avoid transient interference as much as possible, a certain preset time is prolonged after the relay is closed for the first time, and then the alarm judgment is performed. During the charging process after the relay is closed for the first time, no delay judgment is performed. If the relay closing preset time flag is cleared, the relay closing time count is increased by the preset time count. If the sampling filtered value exceeds the voltage threshold value, the alarm second count is increased by the preset second count. The alarm processing condition is that the alarm second count is greater than or equal to the preset threshold value.

[0171] For example, the preset time for the delay judgment when the relay is closed for the first time is set to 1 second, and the alarm judgment is performed after the delay of 1 second. During the charging process after the relay is closed for the first time, the time for which the relay is closed has exceeded 1 second, so the delay is not needed, and the alarm judgment is directly performed. If the relay closing time flag is cleared, the relay closing time count is increased by the preset time count, which is set to 1. However, 1 here does not represent 1 second, but represents the time count in which the time for which the relay has been closed is sequentially increased, or the time in which the program is polled. For example, if the time for which the relay has been closed is 0.2 seconds, the time for which the relay has been closed is 0.3 seconds after the time count is increased by the preset time count, and so on. If the sampling filtered value exceeds the voltage threshold, the alarm second count is increased by the preset second count, which is set to 1. However, 1 here does not represent 1 second, but represents the second count in which the alarm second count is sequentially increased, or the time in which the program is polled. For example, if the alarm second count is 1, the alarm second count is 2 after the second count is increased, and so on. The alarm second count is a program internal time counter. The preset second count, which is added to the alarm second count, is set to 2000. When the alarm second count reaches 2000, 5 seconds have elapsed, and then the alarm processing is performed, and the alarm signal is output. The duration of the output alarm signal is 5 seconds. During the charging process, the alarm processing is performed only when the sampling filtered value exceeds the voltage threshold for 5 consecutive seconds.

[0172] In the twelfth step, if the charging permission flag is cleared, the above alarm judgment is performed.

[0173] The charging pile electric leakage detection method provided in the embodiments of the present application is characterized in that: first, at the moment when the relay is closed, only the signal is sampled and filtered, and no alarm judgment is performed, which effectively prevents the overcurrent false alarm on the PE line caused by the transient charging of the Y capacitor at the moment when the relay is closed; second, for the alarm judgment during the charging process, the alarm is performed only when the sampling filtered value is greater than the alarm threshold for 5 consecutive seconds. The above software and hardware cooperation can greatly reduce the false alarm rate.

[0174] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0175] According to another aspect of the embodiments of the present application, a charging device 1 is provided.

[0176] As shown in Figure 6 , the charging device 1 comprises the charging pile electric leakage detection circuit 100 as described above.

[0177] The input end of the charging device 1 is connected with the output end of the alternating current power supply 2, and the output end of the electric leakage detection circuit 100 is connected with the input end of the alarm device 200.

[0178] Corresponding to the charging pile electric leakage detection method described in the above embodiment, Figure 7 The structure block diagram of the charging pile electric leakage detection device provided by the embodiment of the application is shown, and only the parts related to the embodiment of the application are shown for the convenience of description.

[0179] With reference to Figure 7 The device comprises:

[0180] The induction unit 701 is configured to collect the current flowing through the ground wire of the charging pile based on an induction current module, and output an induction current; the induction current module is coupled to the ground wire of the charging pile;

[0181] The filtering unit 702 is configured to filter the induction current based on a filtering module, and convert the induction current into a voltage signal; the filtering module is connected with the induction current module;

[0182] The output unit 703 is configured to receive the voltage signal based on a detection module, and output an alarm signal based on a target time length of receiving the voltage signal, a voltage value of the voltage signal, and a target alarm parameter.

[0183] It should be noted that the information interaction, execution process and the like between the above devices / units are based on the same concept as the method embodiments of the application, and the specific functions and the technical effects brought by the method embodiments can be referred to the method embodiments part, which will not be described here.

[0184] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above functional units and modules is exemplified, and in actual application, the above functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of software functional unit. In addition, the specific names of the functional units and modules are only for the convenience of mutual distinction, and do not limit the protection scope of the application. The specific working process of the units and modules in the system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0185] In the above embodiments, the description of each embodiment is focused on, and the parts not described or recorded in a certain embodiment can be referred to the relevant description of other embodiments.

[0186] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0187] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / electronic device and method can be implemented in other ways. The apparatus / electronic device embodiments described above are only schematic. The division of the modules or units is only a logical function division, and there can be another division manner in actual implementation. For example, a plurality of units can be combined or integrated into another system, and some features can be ignored or not executed. In addition, the indirect coupling, direct coupling or communication connection between the units shown or discussed can be indirect coupling, direct coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0188] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on a plurality of network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0189] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones. Such modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for detecting electric leakage of a charging pile, characterized in that, The method comprises: an inductive current module is configured to collect a current flowing through a ground wire of a charging pile and output an inductive current; the inductive current module is coupled to the ground wire of the charging pile; a filtering module is configured to filter the inductive current and convert the inductive current into a voltage signal; the filtering module is connected to the inductive current module; a detection module is configured to receive the voltage signal and output an alarm signal based on a target time length during which the voltage signal is received, a voltage value of the voltage signal, and a target alarm parameter; the method comprises: obtaining a closing signal of a relay; determining the target time length based on the closing signal of the relay; when the target time length is greater than a preset time length, determining whether the voltage value of the voltage signal exceeds a voltage threshold value, and if the voltage value exceeds the voltage threshold value, outputting the alarm signal according to a comparison result of the target alarm parameter and a preset threshold value; wherein the preset time length is a time from power-on to voltage signal stabilization; the filtering module comprises a first filtering module, a differential amplification module, and a second filtering module; first and second output ends of the first filtering module are connected to first and second input ends of the differential amplification module, respectively, and the first filtering module is configured to filter common-mode interference signals; an output end of the differential amplification module is connected to an input end of the second filtering module, and the differential amplification module is configured to amplify the voltage signal output by the first filtering module; an output end of the second filtering module is connected to the detection module, and the second filtering module is configured to filter common-mode interference signals; the second filtering module comprises a first filtering circuit, a second operational amplifier unit, and a second filtering circuit; the first filtering circuit is connected to the second operational amplifier unit and is configured to filter common-mode interference signals; the second operational amplifier unit is connected to the second filtering circuit and is configured to follow the voltage signal; the second filtering circuit is connected to the detection module and is configured to filter common-mode interference signals; and / or the first filtering circuit comprises a fifth resistor and a third capacitor; a first end of the fifth resistor is connected to an output end of a first operational amplifier unit, and a second end of the fifth resistor is connected to a second end of the third capacitor and a non-inverting input end of the second operational amplifier unit; a first end of the third capacitor is grounded; the second filtering circuit comprises a sixth resistor and a fourth capacitor; a first end of the sixth resistor is connected to an inverting input end and an output end of the second operational amplifier unit, and a second end of the sixth resistor is connected to a second end of the fourth capacitor and an input end of the detection module; a first end of the fourth capacitor is grounded.

2. The method of claim 1, wherein, Before outputting the alarm signal according to the comparison result of the target alarm parameter and the preset threshold value, the method further comprises: increasing an alarm parameter by a preset second count to obtain the target alarm parameter; outputting the alarm signal according to the comparison result of the target alarm parameter and the preset threshold value comprises: if the target alarm parameter exceeds the preset threshold value, outputting the alarm signal. If the target alarm parameter is less than the preset threshold, the step of collecting the current flowing through the ground wire of the charging pile based on the induced current module and subsequent steps are continued.

3. The method of claim 1, wherein, The induced current module comprises a current transformer, a common-mode inductor, a first resistor and a second resistor. The first output end and the second output end of the current transformer are connected to the first input end and the second input end of the common-mode inductor, respectively. The first output end of the common-mode inductor is connected to the second end of the first resistor, and the second output end is connected to the first end of the second resistor, for filtering the common-mode interference signal of the port. The first end of the first resistor is connected to the second end of the second resistor, and the second end is also connected to the first input end of the filtering module. The first end of the second resistor is also connected to the second input end of the filtering module. The first end of the first resistor is connected to the second end of the second resistor.

4. The method of claim 1, wherein, The first filter module comprises a third resistor, a fourth resistor, a first capacitor and a second capacitor. The first end of the third resistor is connected to the first end of the first capacitor and the first input end of the differential amplification module, and the second end is connected to the second end of the first resistor and the first output end of the common-mode inductor. The first end of the fourth resistor is connected to the first end of the second capacitor and the second input end of the differential amplification module, and the second end is connected to the first end of the second resistor; the second end of the first capacitor is connected to the second end of the second capacitor.

5. The method of claim 1, wherein, The differential amplification module comprises an input impedance matching unit, a decoupling unit and a first operational amplifier unit. The first input end and the second input end of the input impedance matching unit are connected to the first output end and the second output end of the first filter module, respectively; the first output end and the second output end of the input impedance matching unit are connected to the first input end and the second input end of the decoupling unit, respectively. The first output end and the second output end of the decoupling unit are connected to the inverting input end and the non-inverting input end of the first operational amplifier unit, respectively. The output end of the first operational amplifier unit is connected to the input end of the second filter module.

6. An electronic device comprising a charging pile electric leakage detection circuit, characterized in that, The charging pile leakage detection circuit comprises an induced current module, a filtering module and a detection module, and when the charging pile leakage detection circuit works, the method of any one of claims 1 to 5 is executed.

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