Insulation monitoring circuit and detection method thereof

Abstract

The embodiment of the invention provides a detection method of an insulation monitoring circuit and related equipment, which are used for improving the monitoring precision in an insulation monitoring scheme. The method provided by the embodiment of the invention comprises the following steps: respectively sampling resistors on an output live wire of a live wire sampling circuit and an output zero wire of a zero wire sampling circuit to obtain a live wire sampling resistor and a zero wire sampling resistor; based on the sampling frequency and the sampling period, storing all live wire sampling resistors and all null line sampling resistors, and determining the maximum value of all live wire sampling resistors as a live wire resistance calibration value and the maximum value of all null line sampling resistors as a null line resistance calibration value in the sampling period and the sampling frequency; and according to the live wire resistance calibration value and the zero line resistance calibration value, performing judgment with a calibration parameter value of a sampling circuit of at least one ADC to obtain a target judgment result, so as to realize judgment operation of the maximum resistance value among the output live wire, the output zero line and the ground wire according to the target judgment result.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of charging control, and in particular to an insulation monitoring circuit and a detection method thereof. Background Art

[0002] At present, the insulation quality of the live wire and the ground wire in electrical equipment is related to the performance of the electrical equipment. For example, the failure of the insulation between the live wire and the ground wire can easily cause damage to components and even electric shock to personnel. The previous detection method was to use instruments to detect after a power outage. However, in this insulation monitoring solution, due to the influence of X capacitance, there is resistance coupling on the detection waveform, resulting in the dynamic insulation monitoring accuracy during inversion not meeting the set requirements. Summary of the invention

[0003] The embodiments of the present application provide an insulation monitoring circuit and a detection method thereof, which are used to improve the monitoring accuracy in an insulation monitoring scheme.

[0004] A first aspect of an embodiment of the present application provides a detection method for an insulation monitoring circuit, which is applied to an insulation monitoring circuit, wherein the insulation monitoring circuit includes a live line sampling circuit and a neutral line sampling circuit, and the method includes:

[0005] Respectively sampling the resistor located on the output live line of the live line sampling circuit and the output neutral line of the neutral line sampling circuit to obtain a live line sampling resistor and a neutral line sampling resistor;

[0006] Based on the sampling frequency and the sampling period, all live line sampling resistors and all neutral line sampling resistors are stored, and the maximum value of all live line sampling resistors is determined as the live line resistance calibration value, and the maximum value of all neutral line sampling resistors is the neutral line resistance calibration value;

[0007] A target judgment result is obtained based on the live wire resistance calibration value and the neutral wire resistance calibration value and at least one calibrated parameter value of the insulation monitoring circuit, so as to implement a judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire according to the target judgment result.

[0008] Optionally, storing all live line sampling resistors and all neutral line sampling resistors based on the sampling frequency and the sampling period includes:

[0009] Determining the sampling period according to the storage length of the ring buffer and the sampling frequency;

[0010] Based on the sampling frequency, the resistance value of the live line sampling resistor sampled in each sampling frequency is stored in the live line buffer of the ring buffer; the resistance value of the neutral line sampling resistor sampled in each sampling frequency is stored in the neutral line buffer of the ring buffer;

[0011] The resistance values ​​of the live line sampling resistors and the neutral line sampling resistors sampled in one sampling period are determined as all live line sampling resistors and all neutral line sampling resistors.

[0012] Optionally, the step of performing a judgment based on the live wire resistance calibration value and the neutral wire resistance calibration value and at least one calibration parameter value of the insulation monitoring circuit to obtain a target judgment result, and implementing a judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire according to the target judgment result, includes:

[0013] Determine whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than a first calibration parameter value, and obtain a first determination result;

[0014] If the first judgment result is yes, then judging whether the absolute value of the difference between the live line resistance calibration value and the neutral line resistance calibration value is less than a second calibration parameter value, and obtaining a second judgment result;

[0015] If the second judgment result is yes, then judging whether the resistance sum between the live line resistance calibration value and the neutral line resistance calibration value is greater than a third calibration parameter value, and obtaining a third judgment result;

[0016] If the third judgment result is no, executing the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value;

[0017] If the third judgment result is yes, the third judgment result is determined as the target judgment result, so as to issue an insulation warning message according to the target judgment result, and determine whether the resistance sum value is greater than a fourth calibration parameter value to obtain a fourth judgment result;

[0018] If the fourth judgment result is yes, the fourth judgment result is adjusted to the target judgment result, and an insulation shutdown operation is performed on the insulation monitoring circuit according to the target judgment result.

[0019] Optionally, the method further comprises:

[0020] If the second judgment result is no, judging whether the live line resistance calibration value is less than the neutral line resistance calibration value, and obtaining a fifth judgment result;

[0021] If the fifth judgment result is yes, determine whether the zero line resistance calibration value is greater than the fifth calibration parameter value to obtain a sixth judgment result;

[0022] If the sixth judgment result is yes, determining the sixth judgment result as the target judgment result, so as to perform an insulation shutdown operation on the insulation monitoring circuit according to the target judgment result;

[0023] If the sixth judgment result is no, determining whether the zero line resistance calibration value is greater than the sixth calibration parameter value to obtain a seventh judgment result;

[0024] If the seventh judgment result is yes, determining the seventh judgment result as the target judgment result, so as to issue the insulation warning information according to the target judgment result;

[0025] If the seventh judgment result is no, the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value is performed.

[0026] Optionally, the method further comprises:

[0027] If the fifth judgment result is no, determining whether the live wire resistance calibration value is greater than the seventh calibration parameter value to obtain an eighth judgment result;

[0028] If the eighth judgment result is yes, determining the eighth judgment result as the target judgment result, so as to perform an insulation shutdown operation on the insulation monitoring circuit according to the target judgment result;

[0029] If the eighth judgment result is no, determining whether the live wire resistance calibration value is greater than the eighth calibration parameter value to obtain a ninth judgment result;

[0030] If the ninth judgment result is yes, the ninth judgment result is determined as the target judgment result, so as to issue the insulation warning information according to the target judgment result;

[0031] If the ninth judgment result is no, the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value is performed.

[0032] Optionally, the method comprises:

[0033] The fourth calibration parameter value is greater than the third calibration parameter value, the fifth calibration parameter value is greater than the sixth calibration parameter value, and the seventh calibration parameter value is greater than the eighth calibration parameter value.

[0034] Optionally, the method further comprises:

[0035] If the first judgment result is no, the first judgment result is determined as the target judgment result, and it is determined that the insulation monitoring circuit has no fault.

[0036] A second aspect of an embodiment of the present application provides an insulation monitoring circuit, the insulation monitoring circuit comprising: a live line sampling circuit, a neutral line sampling circuit and a controller;

[0037] One end of the controller is connected to the live line sampling circuit and the neutral line sampling circuit respectively, and the other end is connected to the ground line;

[0038] The live wire sampling circuit comprises a live wire sampling resistor, one end of the live wire sampling resistor is connected to the input end of the live wire sampling circuit, and the other end is connected to the controller;

[0039] The zero line sampling circuit comprises a zero line sampling resistor, one end of the zero line sampling resistor is connected to the input end of the zero line sampling circuit, and the other end is connected to the controller;

[0040] The controller is used to implement a judgment operation of the maximum resistance value of the insulation monitoring circuit according to the neutral line sampling resistor corresponding to the neutral line sampling resistor and the live line sampling resistor corresponding to the live line sampling resistor;

[0041] The insulation monitoring circuit is used to execute the detection method of the insulation monitoring circuit according to any one of claims 1 to 7.

[0042] Optionally, the insulation monitoring circuit further includes an operational amplifier;

[0043] The operational amplifier comprises a live line operational amplifier connected to the live line sampling circuit, and a zero line operational amplifier connected to the zero line sampling circuit;

[0044] The positive input pin of the live wire operational amplifier is connected to one end of the live wire sampling resistor and to the input end of the live wire sampling circuit; the negative input pin of the live wire operational amplifier is connected to the other end of the live wire sampling resistor, and the output end of the live wire operational amplifier is connected to the controller;

[0045] The negative input pin of the zero line operational amplifier is connected to one end of the zero line sampling resistor and to the input end of the zero line sampling circuit; the positive input pin of the zero line operational amplifier is connected to the other end of the live line sampling resistor, and the output end of the zero line operational amplifier is connected to the controller;

[0046] The live line buffer in the controller is used to store the resistance value of the live line sampling resistor; the neutral line buffer in the controller is used to store the resistance value of the neutral line sampling resistor.

[0047] Optionally, the live line sampling circuit and / or the neutral line sampling circuit further comprises a first switch, a first resistor located in the live line sampling circuit, and a second resistor located in the neutral line sampling circuit; the first switch is used to control the conduction of the live line sampling circuit or the neutral line sampling circuit;

[0048] The live line sampling circuit further includes a fourth resistor and a second switch connected in parallel with the first resistor, and the neutral line sampling circuit further includes a third resistor and a second switch connected in parallel with the second resistor; the second switch is used to control the fourth resistor to divide the voltage of the live line sampling resistor, or the third resistor to divide the voltage of the neutral line sampling resistor.

[0049] The insulation monitoring circuit provided in the second aspect of the embodiment of the present application is used to execute the detection method of the insulation monitoring circuit described in the first aspect.

[0050] It can be seen from the above technical scheme that the embodiments of the present application have the following advantages: through a detection method of an insulation monitoring circuit disclosed in an embodiment of the present application, without changing the monitoring circuit, the maximum value of dynamic insulation monitoring and the maximum resistance value of the live wire / neutral wire to PE are found through multi-condition judgment to make logical judgments, and the calibration parameters are added to achieve accuracy improvement to meet the set requirements, thereby improving monitoring efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0052] Figure 1 A circuit structure diagram of an insulation monitoring circuit disclosed in an embodiment of the present application;

[0053] Figure 2 A schematic flow chart of a detection method for an insulation monitoring circuit disclosed in an embodiment of the present application;

[0054] Figure 3 A flow chart of another detection method for an insulation monitoring circuit disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0056] It should be noted that the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] See also Figure 1 , Figure 1 A circuit structure diagram of an insulation monitoring circuit disclosed in an embodiment of the present application.

[0059] Depend on Figure 1 It can be seen that the circuit structure is an insulation monitoring circuit. Furthermore, the insulation monitoring circuit can also be understood as a sampling circuit of an analog-to-digital converter (ADC). The insulation monitoring circuit at least includes a live wire sampling circuit, a neutral wire sampling circuit, an operational amplifier and a controller.

[0060] Specifically, one end of the controller (not shown) is connected to the live wire sampling circuit and the neutral wire sampling circuit respectively, and the other end is connected to the ground wire. The live wire sampling circuit includes a live wire sampling resistor, one end of which is connected to the input end of the live wire sampling circuit, and the other end is connected to the controller. The neutral wire sampling circuit includes a neutral wire sampling resistor, one end of which is connected to the input end of the neutral wire sampling circuit, and the other end is connected to the controller. The positive input pin and the negative input pin of the operational amplifier are connected to the two ends of the live wire sampling resistor and the neutral wire sampling resistor. The controller is used to realize the judgment operation of the maximum resistance value of the insulation monitoring circuit (ADC sampling circuit) according to the neutral wire sampling resistor corresponding to the neutral wire sampling resistor, and the live wire sampling resistor corresponding to the live wire sampling resistor.

[0061] Further, the operational amplifier includes a live operational amplifier connected to the live sampling circuit, and a zero line operational amplifier connected to the zero line sampling circuit. The positive input pin of the live operational amplifier is connected to one end of the live sampling resistor and to the input end of the live sampling circuit; the negative input pin of the live operational amplifier is connected to the other end of the live sampling resistor, and the output end (V_L end) of the live operational amplifier is connected to the controller. The negative input pin of the zero line operational amplifier is connected to one end of the zero line sampling resistor and to the input end of the zero line sampling circuit; the positive input pin of the zero line operational amplifier is connected to the other end of the live sampling resistor, and the output end (V_N end) of the zero line operational amplifier is connected to the controller. The controller also includes a ring buffer (a storage software), the live buffer of the ring buffer is used to store the resistance value of the live sampling resistor; the zero line buffer in the controller is used to store the resistance value of the zero line sampling resistor. Further, the ring buffer can also be understood as a ring buffer (ring buffer Buffer).

[0062] Furthermore, combined with Figure 1 , the live line sampling circuit and the neutral line sampling circuit may have the same circuit structure. Among them, the insulation monitoring circuit also includes a first switch RELAY1, a first resistor R1 located in the live line sampling circuit, and a second resistor R2 located in the neutral line sampling circuit; the first switch RELAY1 is used to control the conduction of the live line sampling circuit or the neutral line sampling circuit. The live line sampling circuit also includes a fourth resistor R4 connected in parallel with the first resistor R1 and a second switch RELAY2, and the neutral line sampling circuit also includes a third resistor R3 connected in parallel with the second resistor R2 and a second switch RELAY2. The second switch RELAY2 is used to control the fourth resistor R4 to divide the voltage of the live line sampling resistor RL, or the third resistor R3 to divide the voltage of the neutral line sampling resistor RN.

[0063] Combination Figure 1As shown, the live line operational amplifier and the zero line operational amplifier are respectively connected in parallel with the live line sampling resistor RL and the zero line sampling resistor RN. The corresponding VL is the output end of the live line operational amplifier, and VN is the output end of the zero line operational amplifier. D1, D2, D3, and D4 are a kind of diodes used to control the conduction direction of the circuit, and the details are not repeated here. Correspondingly, the first switch RELAY1 is used to control the conduction of the entire ADC sampling circuit, and the second switch RELAY2 realizes the parallel connection of the R1 resistor or the R2 resistor and the R3 resistor or the R4 resistor, thereby controlling the resistance value between the RL resistor or the RN resistor and the ground wire PE. VREP is the controller described above, and can also be understood as a simulation software that can control the opening or closing of the first switch or the second switch by the final sampled resistance value.

[0064] Furthermore, in one of the feasible technical solutions for the insulation monitoring circuit, the insulation monitoring circuit (i.e., ADC sampling circuit) has two paths, namely the live line sampling circuit (VL_G) and the neutral line sampling circuit (VN_G). The ADC sampling circuit samples the two paths ADC_L and ADC_N respectively, with a sampling frequency of 50us / time, and stores the sampled ADC original values ​​in two ring buffers (Buffer) respectively.

[0065] In one of the feasible technical solutions, the length of the ring buffer is 512 (U16 type), and the data can be updated approximately every 20 to 30 ms (in one of the test results, it can be 25.6 ms). Specifically, a complete cycle is sampled every 20 to 30 ms to obtain a complete waveform. To understand the working principle of the ADC sampling circuit, please refer to Figure 2 .

[0066] For the above Figure 1 The circuit diagram shown in the figure can be found in Figure 2 ,in, Figure 2 The present invention is a flowchart of a detection method for an insulation monitoring circuit disclosed in an embodiment of the present application, including steps 201 to 203.

[0067] 201. Sample the resistors located on the output live line of the live line sampling circuit and the output neutral line of the neutral line sampling circuit respectively to obtain live line sampling resistance and neutral line sampling resistance.

[0068] Combined with the above Figure 1 As shown, the ADC sampling circuit samples the resistors located on the output live line of the live line sampling circuit and the output neutral line of the neutral line sampling circuit respectively to obtain the live line sampling resistor and the neutral line sampling resistor.

[0069] In one specific embodiment, the voltage between the live wire or the neutral wire can be output to control the voltage or current of the resistor on the live wire sampling circuit or the neutral wire sampling circuit, so as to obtain the actual resistance of the sampling resistor under the current voltage waveform or the current current. Specifically, RL or RN can be sampled by the voltage or current of a certain waveform, and the live wire sampling resistance or neutral wire sampling resistance obtained by actual sampling under different waveforms. It should be noted that the live wire sampling resistance or neutral wire sampling resistance described in this embodiment is obtained after the insulation monitoring circuit samples RL or RN.

[0070] 202. Based on the sampling frequency and the sampling period, store all live line sampling resistors and all neutral line sampling resistors, determine that within the sampling period and the sampling frequency, the maximum value of all live line sampling resistors is the live line resistance calibration value, and the maximum value of all neutral line sampling resistors is the neutral line resistance calibration value.

[0071] Furthermore, all live line sampling resistors and all neutral line sampling resistors can be stored based on the sampling frequency and the sampling period, so as to determine that within the sampling period and the sampling frequency, the maximum value of all live line sampling resistors is the live line resistance calibration value, and the maximum value of all neutral line sampling resistors is the neutral line resistance calibration value.

[0072] In one specific embodiment, the insulation monitoring circuit stores the sampled live wire sampling resistance and neutral wire sampling resistance in real time at each sampling frequency (sampling once). Furthermore, in the same sampling period, all the sampled live wire sampling resistances and all the neutral wire sampling resistances are uniformly stored, thereby obtaining all the live wire sampling resistances and all the neutral wire sampling resistances described above. Then, among all the live wire sampling resistances in the same sampling period, the live wire sampling resistance with the maximum value is determined as the live wire resistance calibration value. Among all the neutral wire sampling resistances in the same sampling period, the neutral wire sampling resistance with the maximum value is determined as the neutral wire resistance calibration value.

[0073] 203. According to the live wire resistance calibration value and the neutral wire resistance calibration value, and the calibration parameter value of at least one insulation monitoring circuit, a target judgment result is obtained, so as to implement a judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire according to the target judgment result.

[0074] Then, the target judgment result can be obtained according to the calibration value of the live wire resistance and the calibration value of the neutral wire resistance and the calibration parameter value of the sampling circuit of at least one ADC, so as to realize the judgment operation of the maximum resistance value between the output live wire, the output neutral wire and the ground wire according to the target judgment result.

[0075] In one of the specific embodiments, the calibration parameter value of the insulation monitoring circuit is first set, and then the live wire resistance calibration value and the zero line resistance calibration value are judged and compared with the calibration parameter value. Specifically, the judgment and comparison method includes but is not limited to the size ratio between the live wire resistance calibration value and / or the zero line resistance calibration value and the calibration parameter value, or the size ratio between the sum of the live wire resistance calibration value and the zero line resistance calibration value and the calibration parameter value, and can also be the size ratio between the difference between the live wire resistance calibration value and the zero line resistance calibration value and the calibration parameter value. Furthermore, multiple calibration parameter values ​​can also be set to perform multiple rounds of comparison, which is not limited here.

[0076] Furthermore, through different judgment results, the judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire can be realized according to the final judgment result (i.e., the target judgment result), wherein the judgment operation can be an operation such as issuing an insulation warning or an insulation shutdown.

[0077] Through the detection method of an insulation monitoring circuit disclosed in this embodiment, without changing the insulation monitoring circuit, multi-condition judgment is used to find the maximum value of dynamic insulation monitoring and the maximum resistance value of the live wire / neutral wire to PE to make logical judgments, and calibration parameters are added to achieve accuracy improvement to meet the set requirements, thereby improving the monitoring efficiency as much as possible.

[0078] Figure 3 This is a flow chart of another detection method for an insulation monitoring circuit disclosed in an embodiment of the present application, including steps 301 to 317.

[0079] 301. Sample the resistors located on the output live line of the live line sampling circuit and the output neutral line of the neutral line sampling circuit respectively to obtain live line sampling resistance and neutral line sampling resistance.

[0080] In this embodiment, step 301 is the same as the aforementioned Figure 2 However, it should be noted that, in this embodiment, since the insulation monitoring circuit has two paths, namely VL_G and VN_G, the sampling circuit can sample the two paths ADC_L and ADC_N respectively, so as to obtain the resistance value of the live line sampling resistor corresponding to the output live line and the resistance value of the neutral line sampling resistor corresponding to the output neutral line in one sampling.

[0081] 302. Determine a sampling period according to the storage length and sampling frequency of the circular buffer.

[0082] In this embodiment, since the storage length of the ring buffer is fixed and the sampling frequency can be set in advance, the sampling period of the insulation monitoring circuit can be determined according to the storage length and the sampling frequency. It should be noted that after each round of sampling period, the ring buffer needs to delete the live line sampling resistor or the neutral line sampling resistor stored in itself.

[0083] In one specific embodiment, the annular buffer includes a live line buffer connected to the live line sampling circuit and a zero line buffer connected to the zero line sampling circuit, wherein the live line buffer can store the sampled live line sampling resistance, and the zero line buffer can store the sampled zero line sampling resistance.

[0084] Furthermore, in one of the feasible technical solutions, Figure 1 As shown in the figure, if the buffer length is 512 (U16 type) and the sampling frequency is 50us / time, the sampling period at this time is 25.6ms, which will not be described in detail here.

[0085] 303. Based on the sampling frequency, the resistance value of the live line sampling resistor sampled in each sampling frequency is stored in the live line buffer of the ring buffer; the resistance value of the neutral line sampling resistor sampled in each sampling frequency is stored in the neutral line buffer of the ring buffer, so that the resistance value of the live line sampling resistor and the resistance value of the neutral line sampling resistor sampled in one sampling period are determined as all the live line sampling resistors and all the neutral line sampling resistors.

[0086] Furthermore, in one of the specific embodiments, in each sampling (determined by the sampling frequency), the resistance value of the live line sampling resistor and the resistance value of the neutral line sampling resistor sampled each time are stored in the live line buffer and the neutral line buffer, respectively. Thus, in one sampling cycle, the resistance values ​​of multiple live line sampling resistors and the resistance values ​​of the neutral line sampling resistor can be sampled and obtained. Furthermore, all the sampled live line sampling resistors and neutral line sampling resistors can be determined as all the live line sampling resistors and all the neutral line sampling resistors described above.

[0087] 304. Determine whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value to obtain a first determination result.

[0088] Based on step 303 , it can be determined whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value, thereby obtaining a first determination result.

[0089] In one of the specific embodiments, it is first determined whether any of the maximum values ​​ADC_L_MAX (live line resistance calibration value) and ADC_N_MAX (zero line resistance calibration value) in the buffer of ADC_L and ADC_N is greater than the first calibration parameter value, thereby obtaining a first judgment result. Specifically, the first judgment result is that if any of the resistance calibration values ​​of the live line resistance calibration value or the zero line resistance calibration value is greater than the first calibration parameter value, step 305 is executed; if any of the resistance calibration values ​​of the live line resistance calibration value or the zero line resistance calibration value is not greater than the first calibration parameter value, the first judgment result is determined as the target judgment result, and it is determined that the insulation monitoring circuit is fault-free.

[0090] 305. Determine whether the absolute value of the difference between the live line resistance calibration value and the neutral line resistance calibration value is less than the second calibration parameter value, and obtain a second determination result.

[0091] Based on step 304, if any one of the live line resistance calibration value or the neutral line resistance calibration value is greater than the first calibration parameter value, it is determined whether the absolute value of the difference between the live line resistance calibration value and the neutral line resistance calibration value is less than the second calibration parameter value, thereby obtaining a second judgment result.

[0092] In one specific embodiment, it is determined whether |ADC_L_MAX-ADC_N_MAX| is less than the second calibration parameter value, thereby obtaining a second result. Specifically, the second determination result is that if the absolute value of the difference between the live resistance calibration value and the neutral resistance calibration value is less than the second calibration parameter value, step 306 is executed; if the absolute value of the difference between the live resistance calibration value and the neutral resistance calibration value is not less than the second calibration parameter value, step 309 is executed.

[0093] 306. Determine whether the resistance sum between the live line resistance calibration value and the neutral line resistance calibration value is greater than a third calibration parameter value, and obtain a third determination result.

[0094] Based on step 305, if the absolute value of the difference between the live line resistance calibration value and the neutral line resistance calibration value is less than the second calibration parameter value, it is determined whether the resistance sum between the live line resistance calibration value and the neutral line resistance calibration value is greater than the third calibration parameter value, thereby obtaining a third judgment result.

[0095] In one specific embodiment, it is determined whether (ADC_L_MAX+ADC_N_MAX) is greater than the third calibration parameter value, thereby obtaining a third determination result. Specifically, the third determination result is that if the resistance sum between the live resistance calibration value and the neutral resistance calibration value is greater than the third calibration parameter value, step 307 is executed; if the resistance sum between the live resistance calibration value and the neutral resistance calibration value is not greater than the third calibration parameter value, step 304 is re-executed.

[0096] 307. Determine the third judgment result as the target judgment result, issue an insulation warning message according to the target judgment result, and determine whether the resistance sum value is greater than the fourth calibration parameter value to obtain a fourth judgment result.

[0097] Based on step 306, the third judgment result can be determined as the target judgment result, thereby issuing an insulation warning message according to the target judgment result, and determining whether the resistance sum value is greater than the fourth calibration parameter value, thereby obtaining a fourth judgment result.

[0098] In one specific embodiment, if (ADC_L_MAX+ADC_N_MAX) at this time is greater than the third calibration parameter value, it can be determined that the current judgment result is the target judgment result, and then an insulation warning message is issued, specifically a level 1 insulation warning can be reported. At this time, the monitoring accuracy requirement is 750Ω / V.

[0099] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the resistance value is 220V*750Ω / V*2=330K. At this time, the judgment threshold range can be 330K~500K, where 750Ω / V is the monitoring accuracy requirement, and the third calibration parameter value is selected within the judgment threshold range for sampling the peak value and difference of the neutral line and live line voltage waveform to ground. Further, it can be simply understood as LN-PE resistance <500K~750Ω / V (condition).

[0100] Furthermore, after obtaining the third judgment result, it is possible to further determine whether (ADC_L_MAX+ADC_N_MAX) is greater than the fourth calibration parameter value, thereby obtaining a fourth judgment result. Specifically, the fourth judgment result is that if the resistance sum is greater than the fourth calibration parameter value, step 308 is executed.

[0101] 308. Adjust the fourth judgment result to a target judgment result, and perform an isolation shutdown operation on the sampling circuit of the ADC according to the target judgment result.

[0102] Based on step 307, if the resistance sum value is greater than the fourth calibration parameter value, the fourth judgment result is adjusted to the target judgment result, and an isolation shutdown operation is performed on the sampling circuit of the ADC according to the target judgment result.

[0103] In one specific embodiment, the current fourth judgment result can be determined as the final judgment result, that is, the target judgment result, so that the isolation shutdown operation is performed on the sampling circuit of the ADC according to the target judgment result. Specifically, a level 2 isolation shutdown can be reported. At this time, the monitoring accuracy requirement is 500Ω / V.

[0104] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the resistance value is 220V*500Ω / V=110K. At this time, the judgment threshold range can be 110K~250K, where 500Ω / V is the monitoring accuracy requirement. The fourth calibration parameter value is selected by sampling the peak value and difference of the voltage waveform of the neutral line and the live line to the ground within the judgment threshold range. Further, it can be simply understood as LN-PE resistance <250K~750Ω / V (condition).

[0105] 309. Determine whether the live line resistance calibration value is less than the neutral line resistance calibration value to obtain a fifth determination result.

[0106] Based on step 305, if the absolute value of the difference between the live resistance calibration value and the neutral resistance calibration value is not less than the second calibration parameter value, it is determined whether the live resistance calibration value is less than the neutral resistance calibration value, thereby obtaining a fifth determination result.

[0107] In one specific embodiment, it is determined whether ADC_L_MAX is less than ADC_N_MAX, thereby obtaining a fifth determination result. Specifically, the fifth determination result is that if the live resistance calibration value is less than the neutral resistance calibration value, step 310 is executed; if the live resistance calibration value is not less than the neutral resistance calibration value, step 314 is executed.

[0108] 310. Determine whether the zero line resistance calibration value is greater than the fifth calibration parameter value to obtain a sixth determination result.

[0109] Based on step 309 , if the live line resistance calibration value is less than the neutral line resistance calibration value, it is determined whether the neutral line resistance calibration value is greater than the fifth calibration parameter value, thereby obtaining a sixth determination result.

[0110] In one specific embodiment, it is determined whether ADC_N_MAX is greater than the fifth calibration parameter value. Specifically, the sixth determination result is that if the zero line resistance calibration value is greater than the fifth calibration parameter value, step 311 is executed; if the zero line resistance calibration value is not greater than the fifth calibration parameter value, step 312 is executed.

[0111] 311. Determine the sixth judgment result as a target judgment result, so as to perform an isolation shutdown operation on a sampling circuit of the ADC according to the target judgment result.

[0112] Based on step 310, if the zero line resistance calibration value is greater than the fifth calibration parameter value, the sixth judgment result is determined as the target judgment result, so that the isolation shutdown operation is performed on the sampling circuit of the ADC according to the target judgment result.

[0113] In one specific embodiment, when the zero line resistance calibration value at this time is greater than the fifth calibration parameter value, the sixth judgment result is adjusted to the target judgment result, and the isolation shutdown operation is performed on the ADC sampling circuit according to the target judgment result. Specifically, a level 2 isolation shutdown is reported. At this time, the monitoring accuracy requirement is 500Ω / V.

[0114] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the neutral line resistance calibration value is 220V*500Ω / V=110K. At this time, the judgment threshold range can be 110K~150K, where 500Ω / V is the monitoring accuracy requirement, and the fifth calibration parameter value is selected by sampling the peak value and difference of the neutral line and live line voltage waveform to ground within the judgment threshold range. Further, it can be simply understood as L-PE resistance <150K~750Ω / V (condition).

[0115] 312. Determine whether the zero line resistance calibration value is greater than the sixth calibration parameter value to obtain a seventh determination result.

[0116] Based on step 310 , if the zero line resistance calibration value is not greater than the fifth calibration parameter value, it is determined whether the zero line resistance calibration value is greater than the sixth calibration parameter value to obtain a seventh determination result.

[0117] In one specific embodiment, it is determined whether ADC_N_MAX is greater than the sixth calibration parameter value, thereby obtaining a seventh determination result. Specifically, the seventh determination result is that if the zero line resistance calibration value is greater than the sixth calibration parameter value, step 313 is executed; if the zero line resistance calibration value is not greater than the sixth calibration parameter value, step 304 is executed.

[0118] 313. Determine the seventh judgment result as a target judgment result, and issue an insulation warning message according to the target judgment result.

[0119] Based on step 312, if the zero line resistance calibration value is greater than the sixth calibration parameter value, the seventh judgment result is determined as the target judgment result, so as to issue an insulation warning message according to the target judgment result.

[0120] In one specific embodiment, the seventh judgment result can be determined as the target judgment result, and then based on the seventh judgment result, an insulation warning message is issued, that is, a level 1 insulation warning is reported. At this time, the monitoring accuracy requirement is 750Ω / V.

[0121] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the neutral line resistance calibration value is 220V*750Ω / V=165K. At this time, the judgment threshold range can be 165K~250K, where 750Ω / V is the monitoring accuracy requirement. The sixth calibration parameter value is selected by sampling the peak value and difference of the neutral line and live line voltage waveforms to the ground within the judgment threshold range. Further, it can be simply understood as L-PE resistance <250K~750Ω / V (condition).

[0122] 314. Determine whether the live wire resistance calibration value is greater than the seventh calibration parameter value to obtain an eighth determination result.

[0123] Based on step 309 , if the live line resistance calibration value is not less than the neutral line resistance calibration value, it is determined whether the live line resistance calibration value is greater than the seventh calibration parameter value, thereby obtaining an eighth determination result.

[0124] In one specific embodiment, it is determined whether ADC_L_MAX is greater than the seventh calibration parameter value, thereby obtaining an eighth determination result. Specifically, the eighth determination result is that if the live wire resistance calibration value is greater than the seventh calibration parameter value, step 315 is executed; if the live wire resistance calibration value is not greater than the seventh calibration parameter value, step 316 is executed.

[0125] 315. Determine the eighth judgment result as a target judgment result, so as to perform an isolation shutdown operation on the sampling circuit of the ADC according to the target judgment result.

[0126] Based on step 314 , if the live wire resistance calibration value is greater than the seventh calibration parameter value, the eighth judgment result is determined as the target judgment result, so that the isolation shutdown operation is performed on the sampling circuit of the ADC according to the target judgment result.

[0127] In one specific embodiment, the eighth judgment result can be determined as the final judgment result, thereby determining to perform the insulation shutdown operation, that is, reporting the insulation shutdown of level 2. At this time, the monitoring accuracy requirement is 500Ω / V.

[0128] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the live line resistance calibration value is 220V*500Ω / V=110K. At this time, the judgment threshold range can be 110K~150K, where 500Ω / V is the monitoring accuracy requirement. The seventh calibration parameter value is selected by sampling the peak value and difference of the neutral line and live line voltage waveform to ground within the judgment threshold range. Further, it can be simply understood as LN-PE resistance <150K~750Ω / V (condition).

[0129] 316. Determine whether the live wire resistance calibration value is greater than the eighth calibration parameter value, and obtain a ninth determination result.

[0130] Based on step 314 , if the live wire resistance calibration value is not greater than the seventh calibration parameter value, it is determined whether the live wire resistance calibration value is greater than the eighth calibration parameter value, thereby obtaining a ninth determination result.

[0131] In one specific embodiment, it is determined whether ADC_L_MAX is greater than the eighth calibration parameter value, thereby obtaining a ninth determination result. Specifically, the ninth determination result is that if the live wire resistance calibration value is greater than the eighth calibration parameter value, step 317 is executed; if the live wire resistance calibration value is not greater than the eighth calibration parameter value, step 304 is executed.

[0132] 317. Determine the ninth judgment result as the target judgment result, and issue an insulation warning message according to the target judgment result.

[0133] Based on step 316 , if the live wire resistance calibration value is greater than the eighth calibration parameter value, the ninth judgment result is determined as the target judgment result, so that an insulation warning message is issued according to the target judgment result.

[0134] In one specific embodiment, the ninth judgment result can be determined as the final judgment result, so that insulation warning information can be issued according to the target judgment result, specifically, a level 1 insulation warning can be reported. At this time, the monitoring accuracy requirement is 750Ω / V.

[0135] In one embodiment, when the input voltage between the neutral line and the live line is 220V, the live line resistance calibration value is 220V*750Ω / V=165K. At this time, the judgment threshold range can be 165K~250K, where 750Ω / V is the monitoring accuracy requirement. The eighth calibration parameter value is selected by sampling the peak value and difference of the voltage waveform of the neutral line and the live line to the ground within the judgment threshold range. Further, it can be simply understood as N-PE resistance <250K~750Ω / V (condition).

[0136] In combination with the above steps, in one of the feasible technical solutions, the fourth calibration parameter value is greater than the third calibration parameter value, the fifth calibration parameter value is greater than the sixth calibration parameter value, and the seventh calibration parameter value is greater than the eighth calibration parameter value. Furthermore, the first calibration parameter value is Calibra_A, the second calibration parameter value is Calibra_B, the third calibration parameter value is Calibra_C, the fourth calibration parameter value is Calibra_D, the fifth calibration parameter value is Calibra_E, the sixth calibration parameter value is Calibra_F, the seventh calibration parameter value is Calibra_G, and the eighth calibration parameter value is Calibra_H.

[0137] Among them, the calibration parameter value setting is selected by sampling the peak value and the difference of the neutral line and live line voltage waveform to the ground. For example, in the case of 220V, Calibra_A: 1100; Calibra_B: 150; Calibra_C: 2440; Calibra_D: 2560; Calibra_E: 1690; Calibra_F: 1450; Calibra_G: 1580; Calibra_H: 1330.

[0138] It should also be noted that the level 2 insulation shutdown process may be operations such as disconnecting the first switch, etc. The monitoring accuracy requirement for the level 1 insulation warning is 750Ω / V, and the monitoring accuracy requirement for the level 2 insulation shutdown is 500Ω / V.

[0139] A detection method for an insulation monitoring circuit disclosed in this embodiment uses software to find the maximum value of dynamic insulation monitoring and the maximum resistance of L / N to PE (neutral line / live line to ground) to make logical judgments. Accuracy is improved through multiple judgment bases and conditions, and calibration parameters are added to achieve the set monitoring accuracy requirements.

[0140] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

Claims

1. A detection method for an insulation monitoring circuit, characterized in that: Applied to an insulation monitoring circuit, the insulation monitoring circuit includes a live line sampling circuit and a neutral line sampling circuit, and the method includes: Respectively sampling the resistor located on the output live line of the live line sampling circuit and the output neutral line of the neutral line sampling circuit to obtain a live line sampling resistor and a neutral line sampling resistor; Based on the sampling frequency and the sampling period, all live line sampling resistors and all neutral line sampling resistors are stored, and the maximum value of all live line sampling resistors is determined as the live line resistance calibration value, and the maximum value of all neutral line sampling resistors is the neutral line resistance calibration value; A target judgment result is obtained based on the live wire resistance calibration value and the neutral wire resistance calibration value and at least one calibrated parameter value of the insulation monitoring circuit, so as to implement a judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire according to the target judgment result.

2. The detection method of the insulation monitoring circuit according to claim 1, characterized in that: Based on the sampling frequency and the sampling period, all live line sampling resistors and all neutral line sampling resistors are stored, including: Determining the sampling period according to the storage length of the ring buffer and the sampling frequency; Based on the sampling frequency, the resistance value of the live line sampling resistor sampled in each sampling frequency is stored in the live line buffer of the ring buffer; the resistance value of the neutral line sampling resistor sampled in each sampling frequency is stored in the neutral line buffer of the ring buffer; The resistance values ​​of the live line sampling resistors and the neutral line sampling resistors sampled in one sampling period are determined as all live line sampling resistors and all neutral line sampling resistors.

3. The detection method of the insulation monitoring circuit according to claim 1, characterized in that: The step of judging the live wire resistance calibration value and the neutral wire resistance calibration value and at least one calibration parameter value of the insulation monitoring circuit to obtain a target judgment result, and implementing a judgment operation of the maximum resistance between the output live wire, the output neutral wire and the ground wire according to the target judgment result, includes: Determine whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than a first calibration parameter value, and obtain a first determination result; If the first judgment result is yes, then judging whether the absolute value of the difference between the live line resistance calibration value and the neutral line resistance calibration value is less than a second calibration parameter value, and obtaining a second judgment result; If the second judgment result is yes, then judging whether the resistance sum between the live line resistance calibration value and the neutral line resistance calibration value is greater than a third calibration parameter value, and obtaining a third judgment result; If the third judgment result is no, executing the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value; If the third judgment result is yes, the third judgment result is determined as the target judgment result, so as to issue an insulation warning message according to the target judgment result, and determine whether the resistance sum value is greater than a fourth calibration parameter value to obtain a fourth judgment result; If the fourth judgment result is yes, the fourth judgment result is adjusted to the target judgment result, and an insulation shutdown operation is performed on the insulation monitoring circuit according to the target judgment result.

4. The detection method of the insulation monitoring circuit according to claim 3, characterized in that: The method further comprises: If the second judgment result is no, judging whether the live line resistance calibration value is less than the neutral line resistance calibration value, and obtaining a fifth judgment result; If the fifth judgment result is yes, determine whether the zero line resistance calibration value is greater than the fifth calibration parameter value to obtain a sixth judgment result; If the sixth judgment result is yes, determining the sixth judgment result as the target judgment result, so as to perform an insulation shutdown operation on the insulation monitoring circuit according to the target judgment result; If the sixth judgment result is no, determining whether the zero line resistance calibration value is greater than the sixth calibration parameter value to obtain a seventh judgment result; If the seventh judgment result is yes, determining the seventh judgment result as the target judgment result, so as to issue the insulation warning information according to the target judgment result; If the seventh judgment result is no, the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value is performed.

5. The detection method of the insulation monitoring circuit according to claim 4, characterized in that: The method further comprises: If the fifth judgment result is no, determining whether the live wire resistance calibration value is greater than the seventh calibration parameter value to obtain an eighth judgment result; If the eighth judgment result is yes, determining the eighth judgment result as the target judgment result, so as to perform an insulation shutdown operation on the insulation monitoring circuit according to the target judgment result; If the eighth judgment result is no, determining whether the live wire resistance calibration value is greater than the eighth calibration parameter value to obtain a ninth judgment result; If the ninth judgment result is yes, the ninth judgment result is determined as the target judgment result, so as to issue the insulation warning information according to the target judgment result; If the ninth judgment result is no, the step of judging whether any one of the live line resistance calibration value and the neutral line resistance calibration value is greater than the first calibration parameter value is performed.

6. The detection method of the insulation monitoring circuit according to claim 5, characterized in that: The method comprises: The fourth calibration parameter value is greater than the third calibration parameter value, the fifth calibration parameter value is greater than the sixth calibration parameter value, and the seventh calibration parameter value is greater than the eighth calibration parameter value.

7. The detection method of the insulation monitoring circuit according to claim 3, characterized in that: The method further comprises: If the first judgment result is no, the first judgment result is determined as the target judgment result, and it is determined that the insulation monitoring circuit has no fault.

8. An insulation monitoring circuit, characterized in that: The insulation monitoring circuit comprises: a live line sampling circuit, a neutral line sampling circuit and a controller; One end of the controller is connected to the live line sampling circuit and the neutral line sampling circuit respectively, and the other end is connected to the ground line; The live wire sampling circuit comprises a live wire sampling resistor, one end of the live wire sampling resistor is connected to the input end of the live wire sampling circuit, and the other end is connected to the controller; The zero line sampling circuit comprises a zero line sampling resistor, one end of the zero line sampling resistor is connected to the input end of the zero line sampling circuit, and the other end is connected to the controller; The controller is used to implement a judgment operation of the maximum resistance value of the insulation monitoring circuit according to the neutral line sampling resistor corresponding to the neutral line sampling resistor and the live line sampling resistor corresponding to the live line sampling resistor; The insulation monitoring circuit is used to execute the detection method of the insulation monitoring circuit according to any one of claims 1 to 7.

9. The insulation monitoring circuit according to claim 8, characterized in that: The insulation monitoring circuit also includes an operational amplifier; The operational amplifier comprises a live line operational amplifier connected to the live line sampling circuit, and a zero line operational amplifier connected to the zero line sampling circuit; The positive input pin of the live wire operational amplifier is connected to one end of the live wire sampling resistor and to the input end of the live wire sampling circuit; the negative input pin of the live wire operational amplifier is connected to the other end of the live wire sampling resistor, and the output end of the live wire operational amplifier is connected to the controller; The negative input pin of the zero line operational amplifier is connected to one end of the zero line sampling resistor and to the input end of the zero line sampling circuit; the positive input pin of the zero line operational amplifier is connected to the other end of the live line sampling resistor, and the output end of the zero line operational amplifier is connected to the controller; The live line buffer in the controller is used to store the resistance value of the live line sampling resistor; the neutral line buffer in the controller is used to store the resistance value of the neutral line sampling resistor.

10. The insulation monitoring circuit according to claim 8, characterized in that: The live line sampling circuit and / or the neutral line sampling circuit further comprises a first switch, a first resistor located in the live line sampling circuit, and a second resistor located in the neutral line sampling circuit; the first switch is used to control the conduction of the live line sampling circuit or the neutral line sampling circuit; The live line sampling circuit further includes a fourth resistor and a second switch connected in parallel with the first resistor, and the neutral line sampling circuit further includes a third resistor and a second switch connected in parallel with the second resistor; the second switch is used to control the fourth resistor to divide the voltage of the live line sampling resistor, or the third resistor to divide the voltage of the neutral line sampling resistor.

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