Insulation resistance detection system

Abstract

The utility model discloses an insulation resistance detection system, and belongs to the technical field of power electronics. The insulation resistance detection system is used for determining insulation resistance between an alternating current output line and a protected ground and comprises a control module, an injection source generation circuit and a detection module, the control module is connected with the injection source generation circuit and the detection module, and the injection source generation circuit is connected with the detection module; the control module is used for controlling the detection module to be connected between the AC output line and the protected ground. Controlling the injection source generation circuit to inject at least two groups of different direct-current voltages to the detection module at different moments; acquiring at least two groups of different sampling voltages corresponding to the direct-current voltages acquired by a sampling resistor in the detection module; constructing an equivalent circuit model of the insulation resistance detection system based on the electrical characteristics of each electronic component in the insulation resistance detection system; and calculating the insulation resistance based on the at least two groups of different DC voltages, the at least two groups of different sampling voltages and the equivalent circuit model.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to an insulation impedance detection system. Background Art

[0002] At present, there are two main solutions for insulation testing of AC output lines, one is the balanced bridge solution, and the other is the voltage injection method solution.

[0003] However, the balanced bridge solution cannot detect faults when insulation faults occur on L / N (live wire / neutral wire) at the same time; the AC voltage injection method in the voltage injection method is greatly affected by the Y capacitor (safety capacitor) of the load. The more loads there are, the greater the detection error will be. In actual applications, it is easy to cause false alarms and the application scenarios are very limited; the DC voltage injection method in the voltage injection method mainly uses a single injection voltage method to detect the insulation impedance of L / N. It will produce good detection accuracy in ideal AC voltage output situations, but when applied to actual products, it will produce large detection errors, which will seriously reduce the robustness of product applications. Utility Model Content

[0004] The main purpose of the present application is to provide an insulation impedance detection system, aiming to solve the technical problem of how to accurately detect the insulation impedance of an AC output line.

[0005] To achieve the above object, the present application provides an insulation impedance detection system, which is used to determine the insulation impedance between an AC output line and a protective ground, and includes: a control module, an injection source generation circuit and a detection module;

[0006] The injection source generating circuit is electrically connected to the detection module and the control module respectively, and is used to inject at least two groups of different DC voltages into the detection module at different times under the control of the control module;

[0007] The input end and the output end of the detection module are respectively connected between the AC output line and the protection ground, the controlled end of the detection module is connected to the control module, and the detection module is used to obtain the sampled voltage of the AC output line in real time when the injection source generating circuit injects a DC voltage into the detection module according to the control of the control module;

[0008] The control module is used to calculate the insulation impedance based on at least two groups of different DC voltages, sampling voltages corresponding to the at least two groups of different DC voltages, and an equivalent circuit model constructed based on the electrical characteristics of each electronic component in the insulation impedance detection system.

[0009] Optionally, the injection source generating circuit includes:

[0010] A direct current power supply, wherein a negative electrode of the direct current power supply is connected to a power ground;

[0011] A DC voltage dividing unit, wherein a first end of the DC voltage dividing unit is connected to the positive electrode of the DC power supply, a second end of the DC voltage dividing unit is connected to the detection module, a third end of the DC voltage dividing unit is connected to the power ground, and a controlled end of the DC voltage dividing unit is connected to the control module.

[0012] Optionally, the DC voltage dividing unit includes:

[0013] A voltage-dividing and current-limiting resistor, wherein a first end of the voltage-dividing and current-limiting resistor is connected to the positive electrode of the DC power supply, and a second end of the voltage-dividing and current-limiting resistor is connected to the detection module;

[0014] A first injection source voltage-dividing resistor, wherein a first end of the first injection source voltage-dividing resistor is connected to a second end of the voltage-dividing and current-limiting resistor;

[0015] A second injection source voltage-dividing resistor, wherein a first end of the second injection source voltage-dividing resistor is connected to a second end of the first injection source voltage-dividing resistor, and a second end of the second injection source voltage-dividing resistor is connected to the power ground;

[0016] A third injection source voltage-dividing resistor, a first end of the third injection source voltage-dividing resistor being connected to a first end of the second injection source voltage-dividing resistor;

[0017] A controlled switch tube, wherein the first end of the controlled switch tube is connected to the second end of the third injection source voltage-dividing resistor, the second end of the controlled switch tube is connected to the power ground, and the controlled end of the controlled switch tube is connected to the control module.

[0018] Optionally, when the control module controls the controlled switch tube to be turned off, the third injection source voltage-dividing resistor does not participate in voltage division, and the first injection source voltage-dividing resistor and the second injection source voltage-dividing resistor divide the DC voltage output by the DC power supply to obtain a first DC input voltage;

[0019] When the control module controls the controlled switch tube to be turned on, the third injection source voltage-dividing resistor participates in voltage division, and the parallel impedance of the second injection source voltage-dividing resistor and the third injection source voltage-dividing resistor and the first injection source voltage-dividing resistor divide the DC voltage output by the DC power supply to obtain a second DC input voltage.

[0020] Optionally, the injection source generating circuit further includes:

[0021] A controlled rectifier, wherein the anode of the controlled rectifier is connected to the power ground, the cathode of the controlled rectifier is connected to the second end of the voltage-dividing and current-limiting resistor and the first end of the first injection source voltage-dividing resistor, the controlled end of the controlled rectifier is connected to the second end of the first injection source voltage-dividing resistor, the first end of the second injection source voltage-dividing resistor and the first end of the third injection source voltage-dividing resistor, and the controlled rectifier is used to stabilize the DC voltage and improve the driving capability of the DC voltage.

[0022] Optionally, the detection module includes:

[0023] A controlled switch, wherein a first end of the controlled switch is connected to the AC output line, and a controlled end of the controlled switch is connected to the control module;

[0024] A voltage-dividing sampling unit, wherein a first end of the voltage-dividing sampling unit is connected to a second end of the controlled switch, a second end of the voltage-dividing sampling unit is connected to the injection source generating circuit, a third end of the voltage-dividing sampling unit is connected to the control module, and a fourth end of the voltage-dividing sampling unit is connected to the protection ground.

[0025] Optionally, the voltage division sampling unit includes:

[0026] a first voltage-dividing resistor, wherein a first end of the first voltage-dividing resistor is connected to a second end of the controlled switch, and a second end of the first voltage-dividing resistor is connected to a power ground;

[0027] a second voltage-dividing resistor, wherein a first end of the second voltage-dividing resistor is connected to the injection source generating circuit, and a second end of the second voltage-dividing resistor is connected to the control module;

[0028] A sampling resistor, wherein a first end of the sampling resistor is connected to a second end of the second voltage-dividing resistor, and a second end of the sampling resistor is connected to the protection ground.

[0029] Optionally, when the control module controls the controlled switch to be closed, the detection module is connected between the AC output line and the protective ground, and the control module obtains at least two groups of different sampling voltages corresponding to each of the DC voltages collected by the sampling resistor.

[0030] Optionally, the detection module further includes:

[0031] A bypass capacitor is connected in parallel with the sampling resistor, and is used to filter out interference signals.

[0032] Optionally, the AC output line includes a live line and a neutral line, a first insulation resistor is arranged between the live line and the protective ground, a second insulation resistor is arranged between the neutral line and the protective ground, and the insulation impedance is the parallel resistance of the first insulation resistor and the second insulation resistor.

[0033] In addition, to achieve the above-mentioned purpose, the present application also provides an electronic device, which includes the insulation impedance detection system as described above.

[0034] The present application proposes an insulation impedance detection system, which is used to determine the insulation impedance between the AC output line and the protective ground, including: a control module, an injection source generating circuit and a detection module, wherein the control module is respectively connected to the injection source generating circuit and the detection module, and the injection source generating circuit is connected to the detection module. The control module first controls the detection module to be connected between the AC output line and the protective ground, so that the insulation impedance detection system is connected to the insulation impedance; then controls the injection source generating circuit to inject at least two groups of different DC voltages into the detection module at different times, so that the detection module can generate different sampling voltages based on different DC voltages; then obtains at least two groups of different sampling voltages corresponding to each DC voltage collected by the sampling resistor in the detection module; based on the electrical characteristics of each electronic component in the insulation impedance detection system, constructs an equivalent circuit model of the insulation impedance detection system, which can eliminate the measurement error caused by the DC component in the AC voltage, thereby improving the detection accuracy; finally, the insulation impedance is calculated based on at least two groups of different DC voltages, at least two groups of different sampling voltages and the equivalent circuit model, and an accurate detection result not affected by the AC voltage is obtained. The present application calculates the insulation impedance on the AC side by converting by injecting at least two different DC voltages under the same working condition through electrical relationship, thereby avoiding detection errors caused by non-ideal AC voltage in actual products and being applicable to various load conditions, thus overcoming the technical defects existing in the related art when using a balanced bridge solution, AC voltage injection method or a single injection voltage method for insulation detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0036] Figure 1 A schematic diagram of the structure of an insulation impedance detection system provided in an embodiment of the present application;

[0037] Figure 2 A schematic diagram of the structure of an injection source generating circuit in an insulation impedance detection system provided in an embodiment of the present application;

[0038] Figure 3 for Figure 2Detailed structural diagram of ;

[0039] Figure 4 A schematic diagram of the structure of a detection module in an insulation impedance detection system provided in an embodiment of the present application;

[0040] Figure 5 for Figure 4 Detailed structural diagram of ;

[0041] Figure 6 for Figure 5 Schematic diagram of the equivalent structure.

[0042] Description of Figure Numbers:

[0043]

[0044] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0045] 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.

[0046] It should be noted that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or suggesting 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 the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the meaning of "and / or" appearing in the full text is to include three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B.

[0048] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0049] It should also be understood that the references to "one embodiment" or "some embodiments" described in the specification of the embodiments of the present application mean that one or more embodiments of the embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0050] Currently, there are two main solutions for insulation testing of AC output lines, one is the balanced bridge solution, and the other is the voltage injection method solution. The voltage injection method insulation testing solution is further divided into DC voltage injection method and AC voltage injection method.

[0051] Among the above schemes, the detection and control scheme of the balanced bridge scheme is simple, and is mainly used in situations where the insulation impedance abnormality of L / N is not considered at the same time. It will have a good detection effect when an insulation fault occurs in a single line of L / N, but when insulation faults occur in both lines at the same time, the fault cannot be detected; and although the voltage injection method scheme can detect the insulation impedance of any one line or both lines of the L / N line to PE at the same time, the AC voltage injection method is sensitive to the Y capacitance of the load, and is mainly used in single load applications. Since the AC voltage injection method is greatly affected by the Y capacitance of the load, the more loads there are, the greater the detection error will be, and it is easy to produce errors in practical applications. In the case of a fault, the application scenario is very limited; the DC voltage injection method mainly uses a single injection voltage method to detect the insulation impedance of L / N. The single injection voltage method will produce good detection accuracy in standard AC voltage output situations, but for non-standard AC voltage output situations, the detection accuracy will be relatively poor, that is, the DC voltage injection method is mainly suitable for insulation detection under ideal AC output conditions and has good detection accuracy, but in actual products, the output AC voltage cannot achieve ideal symmetrical output, and there will be a DC component. The existence of the DC component causes the current DC voltage injection scheme to produce a large detection error, and this error seriously reduces the robustness of the product application.

[0052] Based on this, the embodiment of the present application proposes an insulation impedance detection system. By applying the insulation impedance detection system, the insulation impedance of the AC output side can be accurately detected under various load conditions, overcoming the technical defects of various insulation detection schemes in the related art. In practical applications, the detection accuracy of the insulation impedance on the AC side of the inverter is improved through the embodiment of the present application. In addition to preventing the danger of electric shock caused by insulation impedance failure of the output line of the inverter, it also greatly broadens the application scenarios of the inverter, and can effectively avoid the inverter from falsely reporting insulation failures in practical applications, thereby causing the inverter to shut down and fail to work. In particular, for vehicle-mounted inverters, the load types of vehicle-mounted inverters are further broadened, the end customer's satisfaction with vehicle-mounted inverters in various application scenarios is improved, and the sales of new energy vehicles are promoted.

[0053] The insulation impedance detection system provided in the embodiments of the present application is specifically described through the following embodiments.

[0054] The present application embodiment provides an insulation impedance detection system, referring to Figure 1 , Figure 1A schematic diagram of the structure of an insulation impedance detection system provided in an embodiment of the present application, wherein the insulation impedance detection system is used to determine the insulation impedance between an AC output line and a protective ground, and comprises: a control module 100, an injection source generation circuit 300 and a detection module 200, wherein the control module 100 is connected to the injection source generation circuit 300 and the detection module 200 respectively, and the injection source generation circuit 300 is connected to the detection module 200;

[0055] The control module 100 is used to control the detection module 200 to be connected between the AC output line and the protective ground; control the injection source generating circuit 300 to inject at least two groups of different DC voltages into the detection module 200 at different times; obtain at least two groups of different sampling voltages corresponding to each of the DC voltages collected by the sampling resistor in the detection module 200; construct an equivalent circuit model of the insulation impedance detection system based on the electrical characteristics of each electronic component in the insulation impedance detection system; and calculate the insulation impedance based on at least two groups of different DC voltages, at least two groups of different sampling voltages and the equivalent circuit model.

[0056] In this embodiment, the control module 100 may be an MCU (Microcontroller Unit), which is capable of changing the connection relationship between the detection module 200 and the detection object (i.e., the insulation impedance between the AC output line and the protective ground). As an example, when there is a controlled switch between the detection module 200 and the detection object, the control module 100 may connect or disconnect the detection module 200 and the detection object by changing the on / off state of the controlled switch.

[0057] In this embodiment, the injection source generating circuit 300 is electrically connected to the detection module 200 and the control module 100, respectively, and is used to inject at least two groups of different DC voltages into the detection module 200 at different times under the control of the control module 100; the input end and the output end of the detection module 200 are respectively connected between the AC output line and the protective ground, and the controlled end of the detection module 200 is connected to the control module 100. The detection module 200 is used to obtain the sampled voltage of the AC output line in real time when the injection source generating circuit 300 injects a DC voltage into the detection module 200 according to the control of the control module 100; the control module 100 is used to calculate the insulation impedance based on at least two groups of different DC voltages, the sampled voltages corresponding to the at least two groups of different DC voltages, and an equivalent circuit model constructed based on the electrical characteristics of each electronic component in the insulation impedance detection system.

[0058] As an example, when the control module 100 controls the detection module 200 to be connected between the AC output line and the protective ground, it is equivalent to the circuit between the detection module 200 and the insulation impedance being turned on. At this time, if a DC voltage is injected into the input side of the detection module 200, the resistance element in the detection module 200 will divide the DC voltage with the insulation impedance.

[0059] As an example, the injection source generating circuit 300 may be composed of a single DC power supply and a plurality of electronic components, or may be realized only by a DC power supply with adjustable amplitude, or may be formed by a combination of multiple DC power supplies with different amplitudes. Regardless of the type of the injection source generating circuit 300, the amplitude of the DC voltage injected into the detection module 200 may be changed by the control module 100, so as to ensure that the injection source generating circuit 300 can provide at least two groups of DC voltages with different amplitudes to the detection module 200. Since the single injection voltage method in the related art inevitably requires the AC voltage output by the AC output line to detect the insulation impedance, and the AC voltage in the actual product is not as stable as in the ideal case, in this embodiment, the control module 100 controls the injection source generating circuit 300 to inject at least two groups of different DC voltages into the detection module 200 at different times, and then the comparison can be performed based on at least two groups of parameters without changing the working condition of the detection module 200, so that the influence of the AC voltage does not need to be considered when calculating the insulation impedance, and the detection error caused by the DC component of the AC voltage in the actual product is avoided.

[0060] In this embodiment, the DC voltage is equivalent to the injection source of the detection module 200. The control module 100 can collect the voltage across the sampling resistor in the detection module 200 as the sampling voltage. The sampling voltage corresponds to the DC voltage one-to-one. When the DC voltage changes, the sampling voltage will also change. Therefore, when the injection source includes at least two groups of different DC voltages, the sampling voltage collected by the control module 100 based on the sampling resistor also includes at least two groups.

[0061] In this embodiment, according to the component characteristics and circuit principles of the insulation impedance connected between the AC output line and the protective ground, the DC component of the AC voltage can be used as the divided voltage of the insulation impedance as an equivalent DC voltage, and the two insulation resistors connected in parallel between the AC output line and the protective ground can be equivalent to the insulation impedance, thereby constructing an equivalent circuit model of the insulation impedance detection system, which is convenient for ensuring the integrity of various resistance and voltage parameters when calculating the insulation impedance.

[0062] In this embodiment, according to the circuit principle of the equivalent circuit model formed after the detection module 200 is connected between the AC output line and the protective ground, at least two groups of sampled voltages, at least two groups of DC voltages, equivalent DC voltages, each resistance element in the detection module 200 and at least two groups of relationship expressions between the insulation impedance can be obtained. According to each relationship expression, a calculation formula for the insulation impedance can be derived. The various parameters in the formula, namely the voltage and resistance, can be obtained through collection or setting, and then the insulation impedance between the AC output line and the protective ground can be accurately calculated.

[0063] The present embodiment provides an insulation impedance detection system, which is used to determine the insulation impedance between the AC output line and the protective ground, and includes: a control module, an injection source generating circuit and a detection module, wherein the control module is respectively connected to the injection source generating circuit and the detection module, and the injection source generating circuit is connected to the detection module. The control module first controls the detection module to be connected between the AC output line and the protective ground, so that the insulation impedance detection system is connected to the insulation impedance; then controls the injection source generating circuit to inject at least two groups of different DC voltages into the detection module at different times, so that the detection module can generate different sampling voltages based on different DC voltages; then obtains at least two groups of different sampling voltages corresponding to each DC voltage collected by the sampling resistor in the detection module; based on the electrical characteristics of each electronic component in the insulation impedance detection system, an equivalent circuit model of the insulation impedance detection system is constructed, which can eliminate the measurement error caused by the DC component in the AC voltage, thereby improving the detection accuracy; finally, the insulation impedance is calculated based on at least two groups of different DC voltages, at least two groups of different sampling voltages and the equivalent circuit model, and an accurate detection result not affected by the AC voltage is obtained. The present application calculates the insulation impedance on the AC side by converting by injecting at least two different DC voltages under the same working condition through electrical relationship, thereby avoiding detection errors caused by non-ideal AC voltage in actual products and being applicable to various load conditions, thus overcoming the technical defects existing in the related art when using a balanced bridge solution, AC voltage injection method or a single injection voltage method for insulation detection.

[0064] In some possible embodiments, reference Figure 2 , the injection source generating circuit 300 comprises:

[0065] A direct current power supply DC1, wherein a negative electrode of the direct current power supply DC1 is connected to a power ground GND;

[0066] A DC voltage dividing unit 301, wherein a first end of the DC voltage dividing unit 301 is connected to the positive electrode of the DC power supply DC1, a second end of the DC voltage dividing unit 301 is connected to the detection module 200, a third end of the DC voltage dividing unit 301 is connected to the power ground GND, and a controlled end of the DC voltage dividing unit 301 is connected to the control module 100.

[0067] In some possible embodiments, reference Figure 3 , the DC voltage dividing unit 301 comprises:

[0068] A voltage-dividing and current-limiting resistor R14, wherein a first end of the voltage-dividing and current-limiting resistor R14 is connected to the positive electrode of the DC power supply DC1, and a second end of the voltage-dividing and current-limiting resistor R14 is connected to the detection module 200;

[0069] A first injection source voltage-dividing resistor R13, wherein a first end of the first injection source voltage-dividing resistor R13 is connected to a second end of the voltage-dividing current-limiting resistor R14;

[0070] A second injection source voltage-dividing resistor R11, wherein a first end of the second injection source voltage-dividing resistor R11 is connected to a second end of the first injection source voltage-dividing resistor R13, and a second end of the second injection source voltage-dividing resistor R11 is connected to the power ground GND;

[0071] A third injection source voltage-dividing resistor R12, wherein a first end of the third injection source voltage-dividing resistor R12 is connected to a first end of the second injection source voltage-dividing resistor R11;

[0072] A controlled switch tube Q1, wherein a first end of the controlled switch tube Q1 is connected to a second end of the third injection source voltage-dividing resistor R12, a second end of the controlled switch tube Q1 is connected to the power ground GND, and a controlled end of the controlled switch tube Q1 is connected to the control module 100.

[0073] In some feasible embodiments, when the control module 100 controls the controlled switch tube Q1 to be turned off, the third injection source voltage-dividing resistor R12 does not participate in voltage division, and the first injection source voltage-dividing resistor R13 and the second injection source voltage-dividing resistor R11 divide the DC voltage output by the DC power supply DC1 to obtain a first DC input voltage;

[0074] When the control module 100 controls the controlled switch tube Q1 to be turned on, the third injection source voltage-dividing resistor R12 participates in voltage division, and the parallel impedance of the second injection source voltage-dividing resistor R11 and the third injection source voltage-dividing resistor R12 and the first injection source voltage-dividing resistor R13 divide the DC voltage output by the DC power supply DC1 to obtain a second DC input voltage.

[0075] As an example, in this embodiment, the injection source generating circuit 300 may be as follows: Figure 3The injection source generating circuit 300 shown is used to generate two different injection sources, wherein DC1 is an input voltage source for providing a DC voltage, and R14 is a voltage-dividing current-limiting resistor. At time T1 (i.e., the first time), the control module 100 controls Q1 to turn off, and the voltage division of R11 and R13 generates a first DC input voltage Vdc1. At time T2 (i.e., the second time), the control module 100 controls Q1 to turn on, and the parallel impedance of R11 and R12 and the voltage division of R13 generate a second DC input voltage Vdc2. Obviously, the amplitudes of the first DC input voltage Vdc1 and the second DC input voltage Vdc2 are different. The control module 100 changes the state of Q1 by changing the control signal VDC_CTR, for example, a high level turns on Q1, a low level turns off Q1, and the turn-on and turn-off period is ∆t=T2-T1. It can also be a high level turns off Q1, and a low level turns on Q1. This is not limited in this embodiment.

[0076] In some possible embodiments, reference Figure 3 , the injection source generating circuit 300 further includes:

[0077] A controlled rectifier Regulator, wherein the anode of the controlled rectifier Regulator is connected to the power ground GND, the cathode of the controlled rectifier Regulator is connected to the second end of the voltage-dividing and current-limiting resistor R14 and the first end of the first injection source voltage-dividing resistor R13, the controlled end of the controlled rectifier Regulator is connected to the second end of the first injection source voltage-dividing resistor R13, the first end of the second injection source voltage-dividing resistor R11 and the first end of the third injection source voltage-dividing resistor R12, and the controlled rectifier Regulator is used to stabilize the DC voltage and improve the driving capability of the DC voltage.

[0078] In addition, as an example, the above-mentioned injection source generating circuit 300 may also include a controlled rectifier Regulator, the anode of the controlled rectifier Regulator is connected to the power ground GND, the cathode of the controlled rectifier Regulator is connected to the second end of the voltage-dividing and current-limiting resistor R14 and the first end of the first injection source voltage-dividing resistor R13, the controlled end of the controlled rectifier Regulator is connected to the second end of the first injection source voltage-dividing resistor R13, the first end of the second injection source voltage-dividing resistor R11 and the first end of the third injection source voltage-dividing resistor R12, and the controlled rectifier Regulator is used to stabilize the DC voltage and improve the driving capability of the DC voltage.

[0079] In some possible embodiments, reference Figure 4 , the detection module 200 includes:

[0080] A controlled switch S1, wherein a first end of the controlled switch S1 is connected to the AC output line, and a controlled end of the controlled switch S1 is connected to the control module 100;

[0081] A voltage division sampling unit 201, wherein a first end of the voltage division sampling unit 201 is connected to a second end of the controlled switch S1, a second end of the voltage division sampling unit 201 is connected to the injection source generating circuit 300, a third end of the voltage division sampling unit 201 is connected to the control module 100, and a fourth end of the voltage division sampling unit 201 is connected to the protection ground PE.

[0082] In some possible embodiments, reference Figure 5 , the voltage division sampling unit 201 comprises:

[0083] A first voltage-dividing resistor Rd1, wherein a first end of the first voltage-dividing resistor Rd1 is connected to a second end of the controlled switch S1, and a second end of the first voltage-dividing resistor Rd1 is connected to a power ground;

[0084] a second voltage-dividing resistor Rd2, wherein a first end of the second voltage-dividing resistor Rd2 is connected to the injection source generating circuit 300, and a second end of the second voltage-dividing resistor Rd2 is connected to the control module 100;

[0085] A sampling resistor Rs, wherein a first end of the sampling resistor Rs is connected to a second end of the second voltage-dividing resistor Rd2 , and a second end of the sampling resistor Rs is connected to the protection ground PE.

[0086] As an example, when the control module 100 controls the controlled switch S1 to be closed, the detection module 200 is connected between the AC output line and the protective ground PE, and the control module 100 obtains at least two groups of different sampling voltages corresponding to each of the DC voltages collected by the sampling resistor Rs.

[0087] As an example, in this embodiment, taking the dual DC voltage injection method as an example, when the control module 100 controls the controlled switch S1 to be closed, the detection module 200 is connected to the insulation impedance. At this time, the control module 100 controls the injection source generating circuit 300 to inject the first DC input voltage Vdc1 into the detection module 200 through VDC_INJECT at time T1. At this time, the control module 100 can obtain the first sampling voltage Vsense1 by collecting the voltage across the sampling resistor Rs. Then the control module 100 controls the injection source generating circuit 300 to inject the second DC input voltage Vdc2 into the detection module 200 through VDC_INJECT at time T2. At this time, the control module 100 can obtain the second sampling voltage Vsense2 by collecting the voltage across the sampling resistor Rs, thereby realizing dual DC voltage injection detection. The control module 100 performs equivalent conversion on the insulation impedance according to the two sampling signals, and uses the relationship between the insulation impedance after equivalent and the parameters of the insulation impedance detection circuit composed of the detection module 200 to calculate the insulation impedance.

[0088] In some possible embodiments, reference Figure 5 , the detection module 200 further includes:

[0089] A bypass capacitor C1 is connected in parallel with the sampling resistor Rs, and is used to filter out interference signals.

[0090] In some possible embodiments, reference Figure 5 and Figure 6 The AC output line includes a live line and a neutral line, a first insulation resistor is arranged between the live line and the protective ground PE, a second insulation resistor is arranged between the neutral line and the protective ground PE, and the insulation impedance is the parallel resistance of the first insulation resistor and the second insulation resistor.

[0091] As an example, see Figure 5 and Figure 6 , where AC is equivalent to the AC power provided by the AC output line, RN and RL are the insulation resistance of the L / N line (i.e., live wire / neutral wire) to PE (protective ground), RL is the first insulation resistance, and RN is the second insulation resistance. Figure 5 The equivalent circuit model is Figure 6 The voltage provided by DC3 is the equivalent DC voltage Vdc3 after the DC component between L and N is divided by RN and RL, and Rz is the parallel equivalent impedance of RN and RL, that is, the insulation impedance that needs to be detected by the insulation detection system in this embodiment.

[0092] In addition, an embodiment of the present application further provides an electronic device, which includes the insulation impedance detection system provided by the above embodiment.

[0093] Since the electronic device proposed in this embodiment includes the insulation impedance detection system proposed in the above embodiments, it has the beneficial effects of the above embodiments. For details of the specific working process and principle of the insulation impedance detection system, please refer to the insulation impedance detection system provided in the above embodiments, which will not be described one by one here, and all are within the protection scope of this embodiment.

[0094] It should be noted that the technical solutions of the various embodiments of the present application can be combined with each other, but it must be based on the fact that they can be implemented by technical personnel in this field. 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.

[0095] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An insulation impedance detection system, characterized in that: The insulation impedance detection system is used to determine the insulation impedance between the AC output line and the protective ground, and includes: a control module, an injection source generation circuit and a detection module; The injection source generating circuit is electrically connected to the detection module and the control module respectively, and is used to inject at least two groups of different DC voltages into the detection module at different times under the control of the control module; The input end and the output end of the detection module are respectively connected between the AC output line and the protection ground, the controlled end of the detection module is connected to the control module, and the detection module is used to obtain the sampled voltage of the AC output line in real time when the injection source generating circuit injects a DC voltage into the detection module according to the control of the control module; The control module is used to calculate the insulation impedance based on at least two groups of different DC voltages, sampling voltages corresponding to the at least two groups of different DC voltages, and an equivalent circuit model constructed based on the electrical characteristics of each electronic component in the insulation impedance detection system.

2. The insulation impedance detection system according to claim 1, characterized in that: The injection source generating circuit comprises: A direct current power supply, wherein a negative electrode of the direct current power supply is connected to a power ground; A DC voltage dividing unit, wherein a first end of the DC voltage dividing unit is connected to the positive electrode of the DC power supply, a second end of the DC voltage dividing unit is connected to the detection module, a third end of the DC voltage dividing unit is connected to the power ground, and a controlled end of the DC voltage dividing unit is connected to the control module.

3. The insulation impedance detection system according to claim 2, characterized in that: The DC voltage dividing unit comprises: A voltage-dividing and current-limiting resistor, wherein a first end of the voltage-dividing and current-limiting resistor is connected to the positive electrode of the DC power supply, and a second end of the voltage-dividing and current-limiting resistor is connected to the detection module; A first injection source voltage-dividing resistor, wherein a first end of the first injection source voltage-dividing resistor is connected to a second end of the voltage-dividing and current-limiting resistor; A second injection source voltage-dividing resistor, wherein a first end of the second injection source voltage-dividing resistor is connected to a second end of the first injection source voltage-dividing resistor, and a second end of the second injection source voltage-dividing resistor is connected to the power ground; A third injection source voltage-dividing resistor, a first end of the third injection source voltage-dividing resistor being connected to a first end of the second injection source voltage-dividing resistor; A controlled switch tube, wherein the first end of the controlled switch tube is connected to the second end of the third injection source voltage-dividing resistor, the second end of the controlled switch tube is connected to the power ground, and the controlled end of the controlled switch tube is connected to the control module.

4. The insulation impedance detection system according to claim 3, characterized in that: When the control module controls the controlled switch tube to be turned off, the third injection source voltage-dividing resistor does not participate in voltage division, and the first injection source voltage-dividing resistor and the second injection source voltage-dividing resistor divide the DC voltage output by the DC power supply to obtain a first DC input voltage; When the control module controls the controlled switch tube to be turned on, the third injection source voltage-dividing resistor participates in voltage division, and the parallel impedance of the second injection source voltage-dividing resistor and the third injection source voltage-dividing resistor and the first injection source voltage-dividing resistor divide the DC voltage output by the DC power supply to obtain a second DC input voltage.

5. The insulation impedance detection system according to claim 3, characterized in that: The injection source generating circuit also includes: A controlled rectifier, wherein the anode of the controlled rectifier is connected to the power ground, the cathode of the controlled rectifier is connected to the second end of the voltage-dividing and current-limiting resistor and the first end of the first injection source voltage-dividing resistor, the controlled end of the controlled rectifier is connected to the second end of the first injection source voltage-dividing resistor, the first end of the second injection source voltage-dividing resistor and the first end of the third injection source voltage-dividing resistor, and the controlled rectifier is used to stabilize the DC voltage and improve the driving capability of the DC voltage.

6. The insulation impedance detection system according to claim 1, characterized in that: The detection module comprises: A controlled switch, wherein a first end of the controlled switch is connected to the AC output line, and a controlled end of the controlled switch is connected to the control module; A voltage-dividing sampling unit, wherein a first end of the voltage-dividing sampling unit is connected to a second end of the controlled switch, a second end of the voltage-dividing sampling unit is connected to the injection source generating circuit, a third end of the voltage-dividing sampling unit is connected to the control module, and a fourth end of the voltage-dividing sampling unit is connected to the protection ground.

7. The insulation impedance detection system according to claim 6, characterized in that: The voltage division sampling unit comprises: a first voltage-dividing resistor, wherein a first end of the first voltage-dividing resistor is connected to a second end of the controlled switch, and a second end of the first voltage-dividing resistor is connected to a power ground; a second voltage-dividing resistor, wherein a first end of the second voltage-dividing resistor is connected to the injection source generating circuit, and a second end of the second voltage-dividing resistor is connected to the control module; A sampling resistor, wherein a first end of the sampling resistor is connected to a second end of the second voltage-dividing resistor, and a second end of the sampling resistor is connected to the protection ground.

8. The insulation impedance detection system according to claim 7, characterized in that: When the control module controls the controlled switch to be closed, the detection module is connected between the AC output line and the protection ground, and the control module obtains at least two groups of different sampling voltages corresponding to the DC voltages collected by the sampling resistor.

9. The insulation impedance detection system according to claim 7, characterized in that: The detection module also includes: A bypass capacitor is connected in parallel with the sampling resistor, and is used to filter out interference signals.

10. The insulation impedance detection system according to claim 1, characterized in that: The AC output line includes a live line and a neutral line, a first insulation resistor is arranged between the live line and the protective ground, a second insulation resistor is arranged between the neutral line and the protective ground, and the insulation impedance is the parallel resistance of the first insulation resistor and the second insulation resistor.

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