Detection circuit and detection device for photovoltaic insulation impedance

Abstract

The invention discloses a photovoltaic insulation impedance detection circuit and a photovoltaic insulation impedance detection device. The detection circuit comprises an adjusting module, a first end of the adjusting module is connected with a second end of the to-be-detected insulation impedance and a grounding end, and a second end of the adjusting module is connected with a third end of the to-be-detected insulation impedance; the first end of the to-be-tested insulation resistor is connected with the positive electrode end of the photovoltaic panel; the adjusting module is used for outputting test voltage to the second end of the to-be-tested insulation impedance so as to adjust the voltage value of the to-be-tested insulation impedance; the sampling module is connected with the to-be-tested insulation impedance and the adjusting module and is used for generating sampling voltage according to the test voltage; the control module is connected with the control end of the adjusting module and the output end of the sampling module, and the control module is used for adjusting the output voltage of the adjusting module according to test requirements and calculating the resistance value of the insulation impedance to be tested according to the sampling voltage of the sampling module, the voltage value of the photovoltaic panel and the output voltage of the adjusting module. According to the technical scheme provided by the embodiment of the invention, the detection effect on the insulation resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular, to a detection circuit and a detection device for photovoltaic insulation impedance. Background Art

[0002] In recent years, with the continuous increase in global attention to renewable energy, the photovoltaic industry has developed rapidly in many countries and regions. During the long-term use of photovoltaic panels, especially in environments such as high and low temperatures, strong winds, sandstorms, rain and snow, the insulation impedance between the positive and negative electrodes of the photovoltaic panel and the ground may change. If the insulation impedance is too low, it may lead to current leakage, equipment damage, and even serious accidents such as fires and electric shocks, threatening personal safety. Therefore, before starting a photovoltaic power generation system, it is necessary to detect the insulation impedance of the photovoltaic panel to the ground.

[0003] However, the prior art requires an additional electronic switch to be added to the circuit to detect the insulation impedance. During the withstand voltage test, the electronic switch needs to withstand a large withstand voltage value, resulting in low reliability. Therefore, the insulation impedance detection method in the prior art has the problem of poor reliability. Summary of the Invention

[0004] The present invention provides a detection circuit and a detection device for photovoltaic insulation impedance to improve the detection effect of the insulation impedance.

[0005] According to an aspect of the present invention, there is provided a detection circuit for photovoltaic insulation impedance, which is used to detect the insulation impedance to be measured of a photovoltaic panel. The detection circuit includes:

[0006] An adjustment module, the first end of the adjustment module is connected to the second end of the insulation impedance to be measured and the ground end, and the second end of the adjustment module is connected to the third end of the insulation impedance to be measured; the first end of the insulation impedance to be measured is connected to the positive electrode end of the photovoltaic panel; the adjustment module is used to output a test voltage to the second end of the insulation impedance to be measured to adjust the voltage value of the insulation impedance to be measured;

[0007] A sampling module, which is respectively connected to the insulation impedance to be measured and the adjustment module, and is used to generate a sampling voltage according to the test voltage;

[0008] A control module, which is connected to the control end of the adjustment module and the output end of the sampling module. The control module is used to adjust the output voltage of the adjustment module according to the test requirements, and calculate the resistance value of the insulation impedance to be measured according to the sampling voltage of the sampling module, the voltage value of the photovoltaic panel, and the output voltage of the adjustment module.

[0009] Optionally, the sampling module includes: a first sampling unit and a second sampling unit;

[0010] The first ends of the first sampling unit and the second sampling unit are both connected to the adjustment module, and the second ends of the first sampling unit and the second sampling unit are both connected to the third end of the insulation impedance to be measured. The first sampling unit and the second sampling unit are also connected to the control module; the control module is configured to calculate the output voltage of the adjustment module and the voltage of the insulation impedance to be measured according to the sampling voltage of the first sampling unit or the second sampling unit.

[0011] Optionally, the adjustment module includes:

[0012] An inverter unit, the first input end of the inverter unit is connected to the positive extreme of the photovoltaic panel, and the second input end of the inverter unit is connected to the negative extreme of the photovoltaic panel; the inverter unit is configured to invert the direct current output by the photovoltaic panel into alternating current;

[0013] A first voltage output unit and a second voltage output unit, the first end of the first voltage output unit is connected to the first output end of the inverter unit, the second end of the first voltage output unit is connected to the first end of the second voltage output unit, and the second end of the second voltage output unit is connected to the second output end of the inverter unit; the connection point of the first voltage output unit and the second voltage output unit serves as the first end of the adjustment module; the control module is configured to calculate the output voltage value of the first voltage output unit according to the sampling voltage of the first sampling unit; and calculate the output voltage value of the second voltage output unit according to the sampling voltage of the second sampling unit;

[0014] A first voltage dividing unit, the first end of the first voltage dividing unit is connected to the first output end of the inverter unit, and the second end of the first voltage dividing unit is connected to the first end of the first sampling unit;

[0015] A second voltage dividing unit, the first end of the second voltage dividing unit is connected to the second output end of the inverter unit, and the second end of the second voltage dividing unit is connected to the first end of the second sampling unit;

[0016] A filtering unit, the first end of the filtering unit is connected to the first output end of the inverter unit, the second end of the filtering unit is connected to the third output end of the inverter unit, and the third end of the filtering unit is connected to the second output end of the inverter unit; the filtering unit is configured to filter the alternating current output by the inverter unit.

[0017] Optionally, the inverter unit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, and a transformer;

[0018] The first end of the first transistor is connected to the positive terminal of the photovoltaic panel, the second end of the first transistor is connected to the first end of the second transistor, the second end of the second transistor is connected to the negative terminal of the photovoltaic panel, the first end of the third transistor is connected to the positive terminal of the photovoltaic panel, the second end of the third transistor is connected to the first end of the fourth transistor, and the second end of the fourth transistor is connected to the negative terminal of the photovoltaic panel;

[0019] The first input terminal of the transformer is connected to the second end of the first transistor, and the second input terminal of the transformer is connected to the second end of the third transistor; the first output terminal of the transformer is connected to the second end of the sixth transistor, and the second output terminal of the transformer is connected to the second end of the filtering unit;

[0020] The first end of the fifth transistor is connected to the first end of the first voltage output unit, the second end of the fifth transistor is connected to the first end of the sixth transistor, the second end of the sixth transistor is connected to the first end of the seventh transistor, the second end of the seventh transistor is connected to the first end of the eighth transistor, and the second end of the eighth transistor is connected to the second end of the second voltage output unit;

[0021] The fifth transistor and the sixth transistor are used to output a voltage through the first voltage output unit when turned on;

[0022] The seventh transistor and the eighth transistor are used to output a voltage through the second voltage output unit when turned on.

[0023] Optionally, the adjustment module further includes: a fourth voltage dividing unit; the sampling module further includes: a fourth sampling unit;

[0024] The first end of the fourth voltage dividing unit is connected to the second output terminal of the transformer, the second end of the fourth voltage dividing unit is connected to the first end of the fourth sampling unit, and the second end of the fourth sampling unit is connected to the third end of the insulation impedance to be measured; the control module is used to control the inverter unit to perform voltage adjustment according to the sampling voltage of the fourth sampling unit, the voltage value of the first voltage dividing unit or the voltage value of the second voltage dividing unit.

[0025] Optionally, the detection circuit of the photovoltaic insulation impedance further includes: an energy storage capacitor, which is connected in parallel with the photovoltaic panel and is used to store the electric energy output by the photovoltaic panel.

[0026] Optionally, the sampling module further includes:

[0027] A fifth sampling unit, a first end of the fifth sampling unit is connected to the positive electrode end of the photovoltaic panel, a second end of the fifth sampling unit is connected to the sampling module, and a third end of the fifth sampling unit is connected to the negative electrode end of the photovoltaic panel; the fifth sampling unit is configured to generate a sampling voltage according to the voltage value of the photovoltaic panel and the output voltage value of the adjustment module.

[0028] The control module is configured to calculate the resistance value of the to-be-tested insulation impedance according to the voltage value of the photovoltaic panel, the voltage value of the to-be-tested insulation impedance, the output voltage of the adjustment module, and the sampling voltage of the fifth sampling unit.

[0029] Optionally, the fifth sampling unit includes:

[0030] A fifth sampling resistor and a sixth sampling resistor, a first end of the fifth sampling resistor is connected to the positive electrode end of the photovoltaic panel, a second end of the fifth sampling resistor is connected to a second end of the adjustment module, the second end of the fifth sampling resistor is further connected to a first end of the sixth sampling resistor, and a second end of the sixth sampling resistor is connected to the negative electrode end of the photovoltaic panel;

[0031] A first capacitor and a second capacitor; the first capacitor is connected in parallel between the first end and the second end of the fifth sampling resistor, and the second capacitor is connected in parallel between the first end and the second end of the sixth sampling resistor; the first capacitor is configured to sample the voltage value of the fifth sampling resistor, and the second capacitor is configured to sample the voltage value of the sixth sampling resistor; wherein, the voltage value sampled by the first capacitor is the sampling voltage value of the fifth sampling unit.

[0032] Optionally, the sampling module further includes:

[0033] A sixth sampling unit, connected in parallel between the second end and the third end of the to-be-tested insulation impedance, and the control module is configured to generate the voltage value of the to-be-tested insulation impedance according to the sampling voltage of the sixth sampling unit.

[0034] Optionally, the adjustment module further includes:

[0035] A first resistor and a second resistor; a first end of the first resistor is connected to a first end of the to-be-tested insulation impedance, a second end of the first resistor is connected to a second end of the second resistor, and a first end of the second resistor is connected to a second end of the to-be-tested insulation impedance;

[0036] A first switch, a first end of the first switch is connected to the second end of the first resistor, and a second end of the first switch is connected to the negative electrode end of the photovoltaic panel, and the first switch is configured to adjust the voltage value of the to-be-tested insulation impedance and the voltage value of the photovoltaic panel when being turned on or off.

[0037] The control module calculates the resistance value of the insulation impedance to be measured according to the voltage value of the insulation impedance to be measured and the voltage value of the photovoltaic panel.

[0038] Optionally, the first switch includes: a ninth transistor;

[0039] The first end of the ninth transistor is connected to the second end of the first resistor, the second end of the ninth transistor is connected to the negative electrode end of the photovoltaic panel, and the control end of the ninth transistor is connected to the control module;

[0040] The adjustment module further includes: a first clamping diode, and the first clamping diode is connected in parallel with the first resistor.

[0041] Optionally, the sampling module further includes: a seventh sampling unit, a second clamping diode, a third clamping diode, and an eighth sampling unit;

[0042] The first end of the seventh sampling unit is connected to the second end of the insulation impedance to be measured, the second end of the seventh sampling unit is connected to the first end of the eighth sampling unit, and the second end of the eighth sampling unit is connected to the adjustment module; the first end of the second clamping diode is connected to the first end of the insulation impedance to be measured, the second end of the second clamping diode is connected to the first end of the third clamping diode, and the second end of the third clamping diode is connected to the third end of the insulation impedance to be measured;

[0043] The control module calculates the resistance value of the insulation impedance to be measured according to the voltage value of the insulation impedance to be measured, the voltage value of the photovoltaic panel, and the voltage value of the eighth sampling unit.

[0044] According to another aspect of the present invention, there is provided a detection device for photovoltaic insulation impedance, including: the detection circuit for photovoltaic insulation impedance according to any embodiment of the present invention.

[0045] The technical solution provided by the embodiments of the present invention realizes the adjustment of the voltage value of the insulation impedance to be measured by setting an adjustment module, and realizes the voltage detection of the insulation impedance to be measured and the adjustment module by sampling the voltages of the insulation impedance to be measured and the adjustment module by the sampling module. And the calculation of the impedance value of the insulation impedance to be measured is realized through the control module. When calculating the impedance value in the present invention, there is no need to additionally add new hardware structures such as switching devices, and the calculation of the impedance value of the insulation impedance to be measured can be realized by adjusting the output voltage of the adjustment module, which has a good detection effect.

[0046] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0048] Figure 1 FIG. is a schematic structural diagram of a photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0049] Figure 2 FIG. is a schematic structural diagram of another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0050] Figure 3 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0051] Figure 4 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0052] Figure 5 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0053] Figure 6 FIG. is a schematic simulation diagram of a photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0054] Figure 7 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0055] Figure 8 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention;

[0056] Figure 9 FIG. is a schematic structural diagram of yet another photovoltaic insulation impedance detection circuit provided according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0058] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0059] The embodiment of the present invention provides a detection circuit for photovoltaic insulation impedance. Figure 1 It is a schematic structural diagram of a detection circuit for photovoltaic insulation impedance provided by an embodiment of the present invention. Refer to Figure 1 , the detection circuit for photovoltaic insulation impedance is used to detect the insulation impedance 2 to be measured of the photovoltaic panel 1. The detection circuit for photovoltaic insulation impedance includes: an adjustment module 10, a sampling module 20, and a control module 30. The first end of the insulation impedance 2 to be measured is connected to the positive extreme of the photovoltaic panel 1, the third end of the insulation impedance 2 to be measured is connected to the negative extreme of the photovoltaic panel 1, and the second end of the insulation impedance 2 to be measured is connected to the ground terminal. The first end of the adjustment module 10 is connected to the second end of the insulation impedance 2 to be measured, and the second end of the adjustment module 10 is connected to the third end of the insulation impedance 2 to be measured; the adjustment module 10 is used to output a test voltage to the second end of the insulation impedance 2 to be measured to adjust the voltage value of the insulation impedance 2 to be measured. The sampling module 20 is respectively connected to the insulation impedance 2 to be measured and the adjustment module 10, and is used to generate a sampling voltage according to the test voltage. The control module 30 is connected to the control end of the adjustment module 10 and the output end of the sampling module 20. The control module 30 is used to adjust the output voltage of the adjustment module 10 according to the test requirements, and calculate the resistance value of the insulation impedance 2 to be measured according to the sampling voltage of the sampling module 20, the voltage value of the photovoltaic panel 1, and the output voltage of the adjustment module 10.

[0060] Specifically, the control module 30 can be used to control the adjustment module 10 to adjust the output voltage, so that the adjustment module 10 can output test voltages with different voltage values. The sampling module 20 is used to generate a sampling voltage according to the voltage value of the test voltage, and the control module 30 can also calculate the voltage value of the test voltage output by the adjustment module 10 based on this sampling voltage.

[0061] When the second end of the insulation impedance 2 to be measured receives the test voltage output by the adjustment module 10, the insulation impedance 2 to be measured can generate different current values according to the voltage difference between the test voltage and the photovoltaic panel 1, and further cause the insulation impedance 2 to be measured to generate different voltage values. The sampling module 20 can also sample the voltage value of the insulation impedance 2 to be measured, and the control module 30 calculates the voltage value of the insulation impedance 2 to be measured based on this sampling voltage.

[0062] Exemplarily, the adjustment module 10 can adjust and output a fixed-value test voltage according to the test requirements. The control module 30 can list node current and voltage equations for the second end of the insulation impedance 2 to be measured according to the sampling voltage of the sampling module 20, the voltage value of the photovoltaic panel 1, and the output voltage of the adjustment module 10, based on the KCL law (Kirchhoff's current law) and the KVL law (Kirchhoff's voltage law), and an equation about the insulation impedance 2 to be measured can be obtained.

[0063] After obtaining the equation, the control module 30 adjusts the adjustment module 10 to make it output another fixed-value test voltage. The control module 30 re-obtains another equation about the insulation impedance 2 to be measured according to the sampling voltage of the sampling module 20, the voltage value of the photovoltaic panel 1, and the output voltage of the adjustment module 10.

[0064] The control module 30 can calculate the impedance value of the insulation impedance 2 to be measured according to the two different equations.

[0065] The technical solution provided by the embodiment of the present invention realizes the adjustment of the voltage value of the insulation impedance 2 to be measured by setting the adjustment module 10, and realizes the voltage detection of the insulation impedance 2 to be measured and the adjustment module 10 by sampling the voltages of the insulation impedance 2 to be measured and the adjustment module 10 through the sampling module 20. And the impedance value of the insulation impedance 2 to be measured is calculated through the control module 30. When calculating the impedance value in the present invention, there is no need to additionally add new hardware structures such as switching devices, and the impedance value of the insulation impedance 2 to be measured can be calculated by adjusting the output voltage of the adjustment module 10, which has a good detection effect.

[0066] Figure 2 This is a schematic structural diagram of another detection circuit for photovoltaic insulation impedance provided by the embodiment of the present invention. Refer to Figure 2, Optionally, the insulation impedance to be measured includes a first insulation impedance RX and a second insulation impedance RY. The first end of the first insulation impedance RX is connected to the positive electrode end of the photovoltaic panel 1, the second end of the first insulation impedance RX is connected to the first end of the second insulation impedance RY at a first node G, the second end of the second insulation impedance RY is connected to the negative electrode end of the photovoltaic panel 1, and the first node G is connected to the ground end.

[0067] The adjustment module 10 can be used to input a specific voltage to the first node G to adjust the voltage values of the first insulation impedance RX and the second insulation impedance RY.

[0068] Specifically, the first end of the first insulation impedance RX can receive the positive electrode voltage of the photovoltaic panel 1, the second end of the first insulation impedance RX receives the output voltage of the adjustment module 10, and the first insulation impedance RX adjusts the current value flowing through the first insulation impedance RX due to different voltage values at both ends, so that the first insulation impedance RX induces different voltage values. Therefore, the adjustment module 10 can adjust the voltage of the first insulation impedance RX by inputting different voltage values to the second end of the first insulation impedance RX. Similarly, the second insulation impedance RY can also adjust the voltage of the second insulation impedance RY according to different voltage values at the first end.

[0069] Optionally, the adjustment module 10 can be provided with an inverter unit 101, a first voltage division unit 102, and a second voltage division unit 103. The control module can adjust the output voltage of the adjustment module 10 by controlling the inverter unit 101. The sampling module 20 can include a first sampling unit 201 and a second sampling unit 202. The first voltage division unit 102 and the first sampling unit 201 are connected in series between the inverter unit 101 and the second insulation impedance RY, and the second voltage division unit 103 and the second sampling unit 202 are connected in series between the inverter unit 101 and the second insulation impedance RY. The first voltage division unit 102 and the second voltage division unit 103 are used to divide the output voltage of the inverter unit 101, and the first sampling unit 201 and the second sampling unit 202 are used to sample the output voltage of the adjustment module 10. The control module is used to calculate the output voltage of the adjustment module 10 and the voltage of the first insulation impedance RX according to the sampling voltage of the first sampling unit 201 or the second sampling unit 202.

[0070] When the adjustment module 10 inputs a fixed-value voltage to the first node G, based on the KCL law (Kirchhoff's current law) and the KVL law (Kirchhoff's voltage law), writing node current and voltage equations for the first node G, an equation of equality about the first insulation impedance RX and the second insulation impedance RY can be obtained:

[0071]

[0072] Among them, V pThe voltage value of the first insulation impedance RX, V pv The voltage value of the photovoltaic panel 1, V G is the voltage value input to the first node G of the adjustment module 10. R1 is the resistance value after the series connection of the first voltage dividing unit 102 and the first sampling unit 201, and R2 is the resistance value after the series connection of the second voltage dividing unit 103 and the second sampling unit 202. R x is the resistance value of the first insulation impedance RX, R y is the resistance value of the second insulation impedance RY.

[0073] The control module can be used to control the adjustment module 10 to perform voltage adjustment, and make the adjustment module 10 input different voltages to the first node G, so as to adjust the voltages of the first insulation impedance RX and the second insulation impedance RY.

[0074] Exemplarily, at the first moment, the voltage value input to the first node G by the adjustment module 10 is V G,1 , at this time, the voltage value of the photovoltaic panel 1 is V pv,1 , and the voltage value V of the first insulation impedance RX p,1 . At the second moment, the voltage value input to the first node G by the adjustment module 10 is V G,2 , at this time, the voltage value of the photovoltaic panel 1 is V pv,2 , and the voltage value V of the first insulation impedance RX p,2 . Substituting the voltage values at the first moment and the second moment into the above formula respectively, the calculation shows that:

[0075]

[0076] According to the above formula, and substituting the specific numerical values of each parameter, the calculation of the resistance values of the first insulation impedance RX and the second insulation impedance RY can be realized.

[0077] The technical solution provided by the embodiments of the present invention is based on the KCL law and the KVL law. By writing node current and voltage equations for the detection circuit of the photovoltaic insulation impedance, an equation for the first insulation impedance RX and the second insulation impedance RY can be obtained. By setting the adjustment module 10, the voltage adjustment of the first insulation impedance RX and the second insulation impedance RY is realized, and the resistance value calculation of the first insulation impedance RX and the second insulation impedance RY is realized according to the equation for the first insulation impedance RX and the second insulation impedance RY. The present invention can realize the calculation of the resistance value without adding new hardware structures, and will not damage the original circuit structure of the photovoltaic panel 1, and has a good detection effect.

[0078] Figure 3 is a schematic structural diagram of another detection circuit for photovoltaic insulation impedance provided by the embodiments of the present invention. Refer to Figure 3, based on the above embodiments, optionally, the adjustment module 10 further includes: a first voltage output unit 104, a second voltage output unit 105, and a filtering unit 106. The first input terminal of the inverter unit 101 is connected to the positive terminal of the photovoltaic panel 1, and the second input terminal of the inverter unit 101 is connected to the negative terminal of the photovoltaic panel 1; the inverter unit 101 is configured to invert the direct current output by the photovoltaic panel 1 into alternating current. The first end of the first voltage output unit 104 is connected to the first output terminal of the inverter unit 101, the second end of the first voltage output unit 104 is connected to the first end of the second voltage output unit 105, and the second end of the second voltage output unit 105 is connected to the second output terminal of the inverter unit 101; the connection point of the first voltage output unit 104 and the second voltage output unit 105 serves as the first end of the adjustment module 10. The control module is configured to calculate the output voltage value of the first voltage output unit 104 according to the sampled voltage of the first sampling unit 201; calculate the output voltage value of the second voltage output unit 105 according to the sampled voltage of the second sampling unit 202. The first end of the first voltage dividing unit 102 is connected to the first output terminal of the inverter unit 101, and the second end of the first voltage dividing unit 102 is connected to the first end of the first sampling unit 201. The first end of the second voltage dividing unit 103 is connected to the second output terminal of the inverter unit 101, and the second end of the second voltage dividing unit 103 is connected to the first end of the second sampling unit 202. The first end of the filtering unit 106 is connected to the first output terminal of the inverter unit 101, the second end of the filtering unit 106 is connected to the third output terminal of the inverter unit 101, and the third end of the filtering unit 106 is connected to the second output terminal of the inverter unit 101; the filtering unit 106 is configured to filter the alternating current output by the inverter unit 101.

[0079] Wherein, the inverter unit 101 can input electrical energy into the first voltage dividing unit 102, the first sampling unit 201, and the first voltage output unit 104 through the first output terminal, and can also input electrical energy into the second voltage dividing unit 103, the second sampling unit 202, and the second voltage output unit 105 through the second output terminal. Only one of the first output terminal and the second output terminal of the inverter unit 101 is in a conducting state at the same time.

[0080] Exemplarily, when the first output terminal of the inverter unit 101 outputs electric energy, the first voltage output unit 104 receives the electric energy and outputs a voltage, which can be a bias voltage. At the same time, the first sampling unit 201 generates a sampling voltage. The control module calculates the output voltage value of the first voltage output unit 104 according to the voltage value of the first sampling unit 201, and this voltage value is the output voltage value of the regulation module 10. The control module can also calculate the voltage values of the first insulation impedance RX and the second insulation impedance RY according to the voltage value of the first sampling unit 201. The first voltage output unit 104 may include a first inductor L1, the first sampling unit 201 may include a first sampling resistor R1, and the first voltage dividing unit 102 may include a first voltage dividing resistor RF1. The first voltage dividing resistor RF1 can divide the voltage at the first output terminal of the inverter unit 101, and the first sampling resistor R1 can generate a sampling voltage.

[0081] When the second output terminal of the inverter unit 101 outputs electric energy, the second voltage output unit 105 receives the electric energy and outputs a voltage. At the same time, the second sampling unit 202 generates a sampling voltage. The control module calculates the output voltage value of the second voltage output unit 105 according to the voltage value of the second sampling unit 202, and this voltage value is the output voltage value of the regulation module 10. The control module can also calculate the voltage values of the first insulation impedance RX and the second insulation impedance RY according to the voltage value of the second sampling unit 202. The second voltage output unit 105 may include a second inductor L2, the second sampling unit 202 may include a second sampling resistor R2, and the second voltage dividing unit 103 may include a second voltage dividing resistor RF2. The second voltage dividing resistor RF2 can divide the voltage at the second output terminal of the inverter unit 101, and the second sampling resistor R2 can generate a sampling voltage.

[0082] Exemplarily, the filtering unit 106 may include: a first filtering capacitor Cr1, a second filtering capacitor Cr2, and a third filtering capacitor Cr3. The first filtering capacitor Cr1 is connected in parallel between the first output terminal and the third output terminal of the inverter unit 101, the second filtering capacitor Cr2 is connected in parallel between the third output terminal and the second output terminal of the inverter unit 101, and the third filtering capacitor Cr3 is connected in parallel between the first output terminal and the second output terminal of the inverter unit 101, for filtering the electric energy output by the inverter unit 101.

[0083] The inverter unit 101 used in the embodiments of the present invention is the original inverter unit 101 connected to the photovoltaic panel 1. Therefore, when the present invention adjusts the voltages of the first insulation impedance RX and the second insulation impedance RY, there is no need to add new hardware structures, the circuit structure is simple, and the reliability is high. The present invention also realizes the detection of the output voltage of the first voltage output unit 104 by setting the first sampling unit 201 and detecting the sampling voltage of the first sampling resistor R1 through the control module. By setting the second sampling unit 202, the detection of the output voltage of the second voltage output unit 105 is realized by detecting the sampling voltage of the second sampling resistor R2 through the control module. The structures of the first sampling unit 201 and the second sampling unit 202 are simple, do not affect the original circuit structure, and have high reliability.

[0084] Continuing to refer to Figure 3 , on the basis of the above embodiments, optionally, the inverter unit 101 includes: a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, and a transformer T. The first end of the first transistor Q1 is connected to the positive extreme of the photovoltaic panel 1, the second end of the first transistor Q1 is connected to the first end of the second transistor Q2, the second end of the second transistor Q2 is connected to the negative extreme of the photovoltaic panel 2, the first end of the third transistor Q3 is connected to the positive extreme of the photovoltaic panel 1, the second end of the third transistor Q3 is connected to the first end of the fourth transistor Q4, and the second end of the fourth transistor Q4 is connected to the negative extreme of the photovoltaic panel 1. The first input terminal of the transformer T is connected to the second end of the first transistor Q1, and the second input terminal of the transformer T is connected to the second end of the third transistor Q3; the first output terminal of the transformer T is connected to the second end of the sixth transistor Q6, and the second output terminal of the transformer T is connected to the second end of the filtering unit 106. The first end of the fifth transistor Q5 is connected to the first end of the first voltage output unit 104, the second end of the fifth transistor Q5 is connected to the first end of the sixth transistor Q6, the second end of the sixth transistor Q6 is connected to the first end of the seventh transistor Q7, the second end of the seventh transistor Q7 is connected to the first end of the eighth transistor Q8, and the second end of the eighth transistor Q8 is connected to the second end of the second voltage output unit 105. The fifth transistor Q5 and the sixth transistor Q6 are used to output voltage through the first voltage output unit 104 when turned on. The seventh transistor Q7 and the eighth transistor Q8 are used to output voltage through the second voltage output unit 105 when turned on.

[0085] Among them, the control module can adjust the electric energy output by the photovoltaic panel 1 by controlling the on / off of the first transistor Q1, the second transistor Q2, the third transistor Q3, and the fourth transistor Q4. The transformer T can step up or step down the adjusted electric energy and output it through the output terminal of the transformer T.

[0086] When the fifth transistor Q5 and the sixth transistor Q6 are turned on, the seventh transistor Q7 and the eighth transistor Q8 are turned off, and the regulation module 10 outputs a voltage to the first node G through the first voltage output unit 104.

[0087] When the seventh transistor Q7 and the eighth transistor Q8 are turned on, the fifth transistor Q5 and the sixth transistor Q6 are turned off, and the regulation module 10 outputs a voltage to the first node G through the second voltage output unit 105.

[0088] Continue to refer to Figure 3 , optionally, based on the above embodiments, the regulation module 10 further includes: a fourth voltage dividing unit 107; the sampling module 20 further includes: a fourth sampling unit 204. The first end of the fourth voltage dividing unit 204 is connected to the second output end of the transformer T, the second end of the fourth voltage dividing unit 107 is connected to the first end of the fourth sampling unit 204, and the second end of the fourth sampling unit 204 is connected to the third end of the insulation impedance 2 to be measured; the control module is configured to control the inverter unit 101 to perform voltage regulation according to the sampling voltage of the fourth sampling unit 204, the voltage value of the first voltage dividing unit 102, or the voltage value of the second voltage dividing unit 103.

[0089] Wherein, the fourth sampling unit 204 may include a fourth sampling resistor R4, and the fourth voltage dividing unit 107 may include a fourth voltage dividing resistor RF4. The first end of the fourth voltage dividing resistor RF4 is connected to the second output end of the transformer T, the second end of the fourth voltage dividing resistor RF4 is connected to the first end of the fourth sampling resistor R4, and the second end of the fourth sampling resistor R4 is connected to the second end of the first sampling unit 201. The fourth voltage dividing resistor RF4 can be used to divide the voltage at the second output end of the transformer T, and the fourth sampling resistor R4 can be used to generate a sampling voltage.

[0090] Exemplarily, the sampling voltage of the fourth sampling resistor R4 has a certain proportional relationship with the voltage of the first filter capacitor Cr1, and the control module can calculate the voltage of the first filter capacitor Cr1 according to the sampling voltage. When the fifth transistor Q5 and the sixth transistor Q6 are turned on, the voltage of the first filter capacitor Cr1 has a certain proportional relationship with the voltage value that should be output by the first voltage output unit 104. Therefore, the voltage that should be output by the first voltage output unit 104 can be calculated according to the voltage of the first filter capacitor Cr1. If the sampling voltage is different from the voltage of the first voltage output unit 104 calculated by the sampling voltage through the first sampling unit 201, it means that the voltage of the first voltage output unit 104 is abnormal, and the voltage of the first voltage output unit 104 may not be the output voltage value set by the control module, and the control module can control the inverter unit 101 to perform voltage regulation.

[0091] When the seventh transistor Q7 and the eighth transistor Q8 are turned on, the voltage of the first filter capacitor Cr1 has a certain proportional relationship with the voltage value that the second voltage output unit 105 should output. Therefore, the voltage that the second voltage output unit 105 should output can be calculated according to the voltage of the first filter capacitor Cr1. If this voltage is different from the voltage of the second voltage output unit 105 calculated by the sampling voltage through the second sampling unit 202, it indicates that the voltage of the second voltage output unit 105 is abnormal, and the voltage of the second voltage output unit 105 may not be the output voltage value set by the control module. The control module can control the inverter unit 101 to adjust the voltage.

[0092] In the present invention, by providing the fourth sampling unit 204, the voltage detection of the first voltage output unit 104 and the second voltage output unit 105 is realized. When the voltages of the first voltage output unit 104 and the second voltage output unit 105 are not the output voltage values set by the control module, the voltage of the inverter unit 101 can be adjusted, and then the voltages of the first voltage output unit 104 and the second voltage output unit 105 can be adjusted, so that the voltage values input to the first insulation impedance RX and the second insulation impedance RY of the first voltage output unit 104 or the second voltage output unit 105 are more accurate, and it has high reliability.

[0093] Continue to refer to Figure 3 , on the basis of the above embodiments, optionally, the detection circuit of the photovoltaic insulation impedance further includes: a storage capacitor Cm, which is connected in parallel with the photovoltaic panel 1 and is used for storing the electric energy output by the photovoltaic panel 1. Exemplarily, the storage capacitor Cm can be a bus capacitor.

[0094] Optionally, the detection circuit of the photovoltaic insulation impedance can further include: a storage inductor Lm, which is connected in parallel between the first output terminal and the second output terminal of the transformer T.

[0095] Figure 4 It is a schematic structural diagram of another detection circuit of the photovoltaic insulation impedance provided by the embodiment of the present invention. Refer to Figure 4 , on the basis of the above embodiments, optionally, the sampling module 20 further includes: a fifth sampling unit 205. The first end of the fifth sampling unit 205 is connected to the positive terminal of the photovoltaic panel 1, the second end of the fifth sampling unit 205 is connected to the sampling module 20, and the third end of the fifth sampling unit 205 is connected to the negative terminal of the photovoltaic panel 1; the fifth sampling unit 205 is used for generating a sampling voltage according to the voltage value of the photovoltaic panel 1 and the output voltage value of the adjustment module 10. The control module is used for calculating the resistance value of the insulation impedance to be measured according to the voltage value of the photovoltaic panel 1, the voltage value of the insulation impedance to be measured, the output voltage of the adjustment module 10, and the sampling voltage of the fifth sampling unit 205.

[0096] Optionally, the fifth sampling unit 205 includes: a fifth sampling resistor R5, a sixth sampling resistor R6, a first capacitor C1, and a second capacitor C2. The first end of the fifth sampling resistor R5 is connected to the positive electrode end of the photovoltaic panel 1, the second end of the fifth sampling resistor R5 is connected to the second end of the regulation module 10, the second end of the fifth sampling resistor R5 is further connected to the first end of the sixth sampling resistor R6, and the second end of the sixth sampling resistor R6 is connected to the negative electrode end of the photovoltaic panel 1. The first capacitor C1 is connected in parallel between the first end and the second end of the fifth sampling resistor R5, and the second capacitor C2 is connected in parallel between the first end and the second end of the sixth sampling resistor R6; the first capacitor C1 is used to sample the voltage value of the fifth sampling resistor R5, and the second capacitor C2 is used to sample the voltage value of the sixth sampling resistor R6; wherein, the voltage value sampled by the first capacitor C1 is the sampling voltage value of the fifth sampling unit 205.

[0097] Wherein, the fifth sampling unit 205 and the sampling module 20 are connected to the second node O. Based on the KCL law, node current equations are written for the first node G and the second node O, and the following equations can be obtained:

[0098]

[0099] Wherein, V5 is the sampling voltage value of the fifth sampling unit 205, R5 is the resistance value of the fifth sampling resistor R5, and R6 is the resistance value of the sixth sampling resistor R6.

[0100] Based on the KVL law, a voltage equation for the first insulation impedance RX is constructed:

[0101]

[0102] Combining the above two formulas, we can get:

[0103]

[0104] Wherein,

[0105] The control module can be used to control the regulation module 10 to perform voltage regulation, and make the regulation module 10 input different voltages to the first node G, so as to regulate the current and voltage of the first insulation impedance RX and the second insulation impedance RY.

[0106] Exemplarily, at the first moment, the voltage value input by the regulation module 10 to the first node G is V G,3 , at this time, the voltage value of the photovoltaic panel 1 is V pv,3 , the voltage value V of the first insulation impedance RX p,3 , the sampling voltage value V of the second sampling module 4 5,3 . At the second moment, the voltage value input by the regulation module 10 to the first node G is V G,4, at this time, the voltage value of the photovoltaic panel 1 is V pv,4 , the voltage value V of the first insulation impedance RX p,4 , the sampling voltage value V of the second sampling module 4 5,4 . Substitute the voltage values at the first moment and the second moment into the above formula respectively, and the calculation shows that:

[0107]

[0108] According to the above formula, and substituting the specific numerical values of each parameter into the above formula, the resistance values of the first insulation impedance RX and the second insulation impedance RY can be calculated.

[0109] Figure 4 is a schematic structural diagram of another photovoltaic insulation impedance detection circuit provided by an embodiment of the present invention. Refer to Figure 4 , on the basis of the above embodiments, optionally, when the adjustment module 10 inputs different voltages to the first node, the voltage of the first insulation impedance RX will be adjusted. At the same time, the voltage across the fifth sampling resistor R5 will also change accordingly. By setting the fifth sampling resistor R5 and the sixth sampling resistor R6, another calculation method for the resistance values of the first insulation impedance RX and the second insulation impedance RY can be realized.

[0110] Table 1 is a simulation parameter table provided by the present invention.

[0111] Table 1

[0112] Parameter Value Photovoltaic panel voltage value 30V Resistance values of the fifth and sixth sampling resistors 1 MΩ Resistance value of the first voltage dividing unit 8 MΩ Resistance value of the second voltage dividing unit 4 MΩ

[0113] Referring to Table 1, and given that the resistance values of the first insulation impedance RX and the second insulation impedance RY are 30 kΩ. By controlling the fifth transistor Q5 and the sixth transistor Q6 to conduct, a variable DC voltage V G,3 is 311 V. By controlling the seventh transistor Q7 and the eighth transistor Q8 to conduct, a variable DC voltage V G,4 is -311 V. At this time, the sampled V p,3 and V p,4 are respectively substituted into the calculation formulas for the first insulation impedance RX and the second insulation impedance RY and simulated. The simulation results are as shown in Figure 6 . Refer to Figure 6 , the resistance values of the first insulation impedance RX and the second insulation impedance RY are both 30 kΩ. The same as the given value. Therefore, the method for calculating the resistance values of the first insulation impedance RX and the second insulation impedance RY by the above formula is effective.

[0114] Figure 7 is a schematic structural diagram of another photovoltaic insulation impedance detection circuit provided by an embodiment of the present invention. Refer to Figure 7, based on the above embodiments, optionally, the sampling module 20 further includes: a sixth sampling unit 206, connected in parallel between the second end and the third end of the insulation impedance to be measured, and the control module is configured to generate a voltage value of the insulation impedance to be measured according to the sampling voltage of the sixth sampling unit 206.

[0115] Among them, the sixth sampling unit 206 may include a seventh sampling resistor R7. When the seventh sampling resistor R7 is energized, the control module can generate a voltage of the second insulation impedance RY according to the sampling voltage of the sixth sampling unit 206.

[0116] Continue to refer to Figure 7 , based on the above embodiments, optionally, the adjustment module 10 further includes: a first resistor RD1, a second resistor RD2, and a first switch 108. The first end of the first resistor RD1 is connected to the first end of the insulation impedance to be measured, the second end of the first resistor RD1 is connected to the second end of the second resistor RD2, and the first end of the second resistor RD2 is connected to the second end of the insulation impedance to be measured. The first end of the first switch 108 is connected to the second end of the first resistor RD1, and the second end of the first switch 108 is connected to the negative terminal of the photovoltaic panel 1. The first switch 108 is configured to adjust the voltage value of the insulation impedance to be measured and the voltage value of the photovoltaic panel 1 when conducting or turning off; the control module calculates the resistance value of the insulation impedance to be measured according to the voltage value of the insulation impedance to be measured and the voltage value of the photovoltaic panel 1.

[0117] Among them, the first switch 108 is used to connect or disconnect the connection between the second ends of the first resistor RD1 and the second resistor RD2 and the negative terminal of the photovoltaic panel 1, thereby adjusting the voltage value of the second insulation impedance RY and the voltage value of the photovoltaic panel 1. The sixth sampling unit 206 can be used to sample the voltage value of the second insulation impedance RY.

[0118] When the first switch 108 disconnects the connection between the second ends of the first resistor RD1 and the second resistor RD2 and the negative terminal of the photovoltaic panel 1, based on the KCL law, a node current equation is written for the first node G, and the following equation can be obtained:

[0119]

[0120] Among them, RD1 is the resistance value of the first resistor RD1, RD2 is the resistance value of the second resistor RD2, V q,5 is the voltage value of the second insulation impedance RY, V pv,5 is the voltage value of the photovoltaic panel 1, R z is the resistance value after the second insulation impedance RY and the sixth sampling unit 206 are connected in parallel.

[0121] When the first switch 108 connects the second ends of the first resistor RD1 and the second resistor RD2 to the negative terminal of the photovoltaic panel 1, based on the KVL law, a node voltage equation is written for the first node G, and the following equation can be obtained:

[0122]

[0123] Among them, V q,6 is the voltage value of the second insulation impedance RY after the first switch 108 is turned on, and V pv,6 is the voltage value of the photovoltaic panel 1 after the first switch 108 is turned on.

[0124] Combining the above two equations, we can get:

[0125]

[0126] Since R z is the resistance value after the second insulation impedance RY and the sixth sampling unit 206 are connected in parallel, which includes the resistance of the seventh sampling resistor R7. It is necessary to remove the resistance of the seventh sampling resistor R7 from R z to obtain the resistance value of the second insulation impedance RY.

[0127] Continuing to refer to Figure 7 , on the basis of the above embodiments, optionally, the first switch 108 includes: a ninth transistor Q9. The first end of the ninth transistor Q9 is connected to the second end of the first resistor RD1, the second end of the ninth transistor Q9 is connected to the negative terminal of the photovoltaic panel 1, and the control end of the ninth transistor Q9 is connected to the control module.

[0128] Among them, when the ninth transistor Q9 is turned off, the connection between the second ends of the first resistor RD1 and the second resistor RD2 and the negative terminal of the photovoltaic panel 1 is cut off. When the ninth transistor Q9 is turned on, the connection between the second ends of the first resistor RD1 and the second resistor RD2 and the negative terminal of the photovoltaic panel 1 is connected.

[0129] Continuing to refer to Figure 7 , on the basis of the above embodiments, optionally, the adjustment module further includes: a clamping diode VD1, and the clamping diode VD1 is connected in parallel with the first resistor RD1.

[0130] Among them, the clamping diode VD1 uses the one-way conductivity of the diode to limit the voltage. The diode conducts when it is forward-biased and cuts off when it is reverse-biased. When the voltage in the first resistor RD1 reaches a certain level, the diode conducts, stabilizing the voltage at a specific value to prevent damage to the first resistor RD1 caused by excessive or too low voltage.

[0131] Figure 8This is a schematic diagram of another detection circuit for photovoltaic insulation impedance provided by an embodiment of the present invention. Refer to Figure 8 , based on the above embodiments, optionally, the sampling module 20 further includes: a seventh sampling unit 207, a second clamping diode VD2, a third clamping diode VD3, and an eighth sampling unit 208; a first end of the seventh sampling unit 207 is connected to a second end of the insulation impedance 2 to be measured, a second end of the seventh sampling unit 207 is connected to a first end of the eighth sampling unit 208, and a second end of the eighth sampling unit 208 is connected to the adjustment module 10; a first end of the second clamping diode VD2 is connected to a first end of the insulation impedance 2 to be measured, a second end of the second clamping diode VD2 is connected to a first end of the third clamping diode VD3, and a second end of the third clamping diode VD3 is connected to a third end of the insulation impedance 2 to be measured; the control module calculates the resistance value of the insulation impedance 2 to be measured according to the voltage value of the insulation impedance 2 to be measured, the voltage value of the photovoltaic panel 1, and the voltage value of the eighth sampling unit 208.

[0132] Among them, the seventh sampling unit 207 may include an eighth sampling resistor R8, and the eighth sampling unit 208 may include a ninth sampling resistor R9. When the adjustment module 10 outputs a fixed-value voltage, based on the KCL law, a node current equation is written for the first node G, and the following equation can be obtained:

[0133]

[0134] V iso is the voltage value of the ninth sampling resistor, and R9 is the resistance value of the ninth sampling resistor.

[0135] Then, based on the KVL law, a voltage equation is written, and the following equation can be obtained:

[0136]

[0137] Among them, V H is the voltage value output by the adjustment module, and R8 is the resistance value of the eighth sampling resistor.

[0138] By combining the above two equations, we can get:

[0139]

[0140] Figure 9 This is a schematic diagram of another detection circuit for photovoltaic insulation impedance provided by an embodiment of the present invention. Refer to Figure 9 , based on the above embodiments, optionally, taking a dual-active-bridge-type photovoltaic micro-inverter as an example, the voltage output by the adjustment module is from the low-voltage side of the transformer T. A second end of the ninth sampling resistor R9 is connected to a first end of the second transistor Q2.

[0141] By adjusting the on / off states of the first transistor Q1 and the second transistor Q2, the voltage value output by the adjustment module can be adjusted.

[0142] When the first transistor Q1 is turned on and the second transistor Q2 is turned off, the voltage value output by the adjustment module is V H，1 , the voltage value of the ninth sampling resistor is V iso，1 , the voltage value of the photovoltaic panel 1 is V pv,7 .

[0143] When the first transistor Q1 is turned off and the second transistor Q2 is turned on, the voltage value output by the adjustment module is V H，2 , the voltage value of the ninth sampling resistor is V iso，2 , the voltage value of the photovoltaic panel 1 is V pv,8 .

[0144] The calculation of R z and R y is as follows:

[0145]

[0146] According to the above formula, and substituting the specific values of each parameter into the above formula, the resistance values of the first insulation impedance RX and the second insulation impedance RY can be calculated.

[0147] The embodiment of the present invention also provides a detection device for photovoltaic insulation impedance. The device includes: the detection circuit for photovoltaic insulation impedance provided by any embodiment of the present invention, which has beneficial effects similar to those of the detection circuit and will not be elaborated here.

[0148] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0149] The above specific implementation manners do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A photovoltaic insulation impedance detection circuit, characterized in that: Used to detect the insulation impedance of a photovoltaic panel, the detection circuit comprises: A regulating module, wherein the first end of the regulating module is connected to the second end of the insulation impedance to be measured and the ground end, and the second end of the regulating module is connected to the third end of the insulation impedance to be measured; the first end of the insulation impedance to be measured is connected to the positive terminal of the photovoltaic panel; the regulating module is used to output a test voltage to the second end of the insulation impedance to be measured to adjust the voltage value of the insulation impedance to be measured; A sampling module, connected to the insulation impedance to be measured and the adjustment module respectively, and used to generate a sampling voltage according to the test voltage; A control module is connected to the control end of the regulating module and the output end of the sampling module. The control module is used to adjust the output voltage of the regulating module according to the test requirements, and calculate the resistance value of the insulation impedance to be measured according to the sampling voltage of the sampling module, the voltage value of the photovoltaic panel and the output voltage of the regulating module.

2. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that: The sampling module comprises: a first sampling unit and a second sampling unit; The first ends of the first sampling unit and the second sampling unit are both connected to the adjustment module, the second ends of the first sampling unit and the second sampling unit are both connected to the third end of the insulation impedance to be measured, and the first sampling unit and the second sampling unit are also connected to the control module; the control module is used to calculate the output voltage of the adjustment module and the voltage of the insulation impedance to be measured according to the sampling voltage of the first sampling unit or the second sampling unit.

3. The photovoltaic insulation impedance detection circuit according to claim 2, characterized in that: The adjustment module comprises: An inverter unit, wherein a first input end of the inverter unit is connected to the positive terminal of the photovoltaic panel, and a second input end of the inverter unit is connected to the negative terminal of the photovoltaic panel; the inverter unit is used to invert the direct current output by the photovoltaic panel into alternating current; A first voltage output unit and a second voltage output unit, wherein the first end of the first voltage output unit is connected to the first output end of the inverter unit, the second end of the first voltage output unit is connected to the first end of the second voltage output unit, and the second end of the second voltage output unit is connected to the second output end of the inverter unit; the connection between the first voltage output unit and the second voltage output unit serves as the first end of the regulating module; the control module is used to calculate the output voltage value of the first voltage output unit according to the sampled voltage of the first sampling unit; and calculate the output voltage value of the second voltage output unit according to the sampled voltage of the second sampling unit; a first voltage dividing unit, wherein a first end of the first voltage dividing unit is connected to a first output end of the inverter unit, and a second end of the first voltage dividing unit is connected to a first end of the first sampling unit; a second voltage dividing unit, wherein a first end of the second voltage dividing unit is connected to a second output end of the inverter unit, and a second end of the second voltage dividing unit is connected to a first end of the second sampling unit; A filter unit, wherein a first end of the filter unit is connected to a first output end of the inverter unit, a second end of the filter unit is connected to a third output end of the inverter unit, and a third end of the filter unit is connected to a second output end of the inverter unit; the filter unit is used to filter the alternating current output by the inverter unit.

4. The photovoltaic insulation impedance detection circuit according to claim 3, characterized in that: The inverter unit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor and a transformer; The first end of the first transistor is connected to the positive terminal of the photovoltaic panel, the second end of the first transistor is connected to the first end of the second transistor, the second end of the second transistor is connected to the negative terminal of the photovoltaic panel, the first end of the third transistor is connected to the positive terminal of the photovoltaic panel, the second end of the third transistor is connected to the first end of the fourth transistor, and the second end of the fourth transistor is connected to the negative terminal of the photovoltaic panel; The first input end of the transformer is connected to the second end of the first transistor, and the second input end of the transformer is connected to the second end of the third transistor; the first output end of the transformer is connected to the second end of the sixth transistor, and the second output end of the transformer is connected to the second end of the filtering unit; The first end of the fifth transistor is connected to the first end of the first voltage output unit, the second end of the fifth transistor is connected to the first end of the sixth transistor, the second end of the sixth transistor is connected to the first end of the seventh transistor, the second end of the seventh transistor is connected to the first end of the eighth transistor, and the second end of the eighth transistor is connected to the second end of the second voltage output unit; The fifth transistor and the sixth transistor are used to output voltage through the first voltage output unit when they are turned on; The seventh transistor and the eighth transistor are configured to output a voltage through the second voltage output unit when being turned on.

5. The photovoltaic insulation impedance detection circuit according to claim 4, characterized in that: The regulating module further includes: a fourth voltage dividing unit; the sampling module further includes: a fourth sampling unit; The first end of the fourth voltage divider unit is connected to the second output end of the transformer, the second end of the fourth voltage divider unit is connected to the first end of the fourth sampling unit, and the second end of the fourth sampling unit is connected to the third end of the insulation impedance to be measured; the control module is used to control the inverter unit to perform voltage regulation according to the sampling voltage of the fourth sampling unit, the voltage value of the first voltage divider unit or the voltage value of the second voltage divider unit.

6. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that: The photovoltaic insulation impedance detection circuit also includes: an energy storage capacitor connected in parallel with the photovoltaic panel and used for storing the electric energy output by the photovoltaic panel.

7. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that: The sampling module also includes: A fifth sampling unit, wherein a first end of the fifth sampling unit is connected to the positive terminal of the photovoltaic panel, a second end of the fifth sampling unit is connected to the sampling module, and a third end of the fifth sampling unit is connected to the negative terminal of the photovoltaic panel; the fifth sampling unit is used to generate a sampling voltage according to the voltage value of the photovoltaic panel and the output voltage value of the regulating module; The control module is used to calculate the resistance value of the insulation impedance to be measured according to the voltage value of the photovoltaic panel, the voltage value of the insulation impedance to be measured, the output voltage of the regulation module and the sampling voltage of the fifth sampling unit.

8. The photovoltaic insulation impedance detection circuit according to claim 7, characterized in that: The fifth sampling unit comprises: a fifth sampling resistor and a sixth sampling resistor, wherein the first end of the fifth sampling resistor is connected to the positive terminal of the photovoltaic panel, the second end of the fifth sampling resistor is connected to the second end of the adjustment module, the second end of the fifth sampling resistor is also connected to the first end of the sixth sampling resistor, and the second end of the sixth sampling resistor is connected to the negative terminal of the photovoltaic panel; a first capacitor and a second capacitor; the first capacitor is connected in parallel between the first end and the second end of the fifth sampling resistor, and the second capacitor is connected in parallel between the first end and the second end of the sixth sampling resistor; the first capacitor is used to sample the voltage value of the fifth sampling resistor, and the second capacitor is used to sample the voltage value of the sixth sampling resistor; wherein the voltage value sampled by the first capacitor is the sampled voltage value of the fifth sampling unit.

9. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that: The sampling module also includes: The sixth sampling unit is connected in parallel between the second end and the third end of the insulation impedance to be measured, and the control module is used to generate the voltage value of the insulation impedance to be measured according to the sampling voltage of the sixth sampling unit.

10. The photovoltaic insulation impedance detection circuit according to claim 9, characterized in that: The adjustment module also includes: A first resistor and a second resistor; a first end of the first resistor is connected to a first end of the insulation impedance to be measured, a second end of the first resistor is connected to a second end of the second resistor, and a first end of the second resistor is connected to a second end of the insulation impedance to be measured; a first switch, wherein a first end of the first switch is connected to a second end of the first resistor, a second end of the first switch is connected to a negative terminal of the photovoltaic panel, and the first switch is used to adjust a voltage value of the insulation impedance to be measured and a voltage value of the photovoltaic panel when the first switch is turned on or off; The control module calculates the resistance value of the insulation impedance to be measured according to the voltage value of the insulation impedance to be measured and the voltage value of the photovoltaic panel.

11. The photovoltaic insulation impedance detection circuit according to claim 10, characterized in that: The first switch comprises: a ninth transistor; The first end of the ninth transistor is connected to the second end of the first resistor, the second end of the ninth transistor is connected to the negative terminal of the photovoltaic panel, and the control end of the ninth transistor is connected to the control module; The regulating module further includes: a first clamping diode, wherein the first clamping diode is connected in parallel with the first resistor.

12. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that: The sampling module further includes: a seventh sampling unit, a second clamping diode, a third clamping diode and an eighth sampling unit; The first end of the seventh sampling unit is connected to the second end of the insulation impedance to be measured, the second end of the seventh sampling unit is connected to the first end of the eighth sampling unit, and the second end of the eighth sampling unit is connected to the adjustment module; the first end of the second clamping diode is connected to the first end of the insulation impedance to be measured, the second end of the second clamping diode is connected to the first end of the third clamping diode, and the second end of the third clamping diode is connected to the third end of the insulation impedance to be measured; The control module calculates the resistance value of the insulation impedance to be measured according to the voltage value of the insulation impedance to be measured, the voltage value of the photovoltaic panel and the voltage value of the eighth sampling unit.

13. A photovoltaic insulation impedance detection device, characterized in that: include: The photovoltaic insulation impedance detection circuit according to any one of claims 1 to 12.

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