Insulation impedance measurement system and method, and optical storage hybrid energy system

Abstract

An insulation impedance measurement system and method, and an optical storage hybrid energy system. The insulation impedance measurement system is used for measuring the insulation impedance in an optical storage hybrid energy system. In the insulation impedance measurement system, one end of a first auxiliary measurement circuit is connected to a negative electrode of each photovoltaic string and a negative electrode of a battery module, one end of a second auxiliary measurement circuit is connected to a positive electrode of the battery module, and the other end of the first auxiliary measurement circuit and the other end of the second auxiliary measurement circuit are connected to a reference voltage end; a processor controls an inverter module (110) to set the output voltage of each photovoltaic string and the bus voltage of a line where the battery module is located, controls, on the basis of the set voltages, the first auxiliary measurement circuit and the second auxiliary measurement circuit to measure the voltages of the negative electrode of each photovoltaic string and of the negative electrode of the battery module for the reference voltage end, and calculates the impedance value of each insulation impedance.

Description

Insulation impedance detection system, method and photovoltaic storage hybrid energy system Technical Field

[0001] The present disclosure relates to the field of circuit technology, and in particular to an insulation impedance detection system, method, and a photovoltaic and energy storage hybrid energy system. Background Art

[0002] The mainstream topology of a PV-storage hybrid inverter lacks an output transformer, requiring the DC side to be insulated from the ground. In this circuit topology, it is crucial to measure the insulation impedance between the PV strings and the energy storage battery and the ground. Therefore, insulation impedance testing is required for this circuit topology.

[0003] Summary of the Invention

[0004] The present disclosure provides an insulation impedance detection system, method, and photovoltaic-storage hybrid energy system, which are beneficial for simplifying the control of auxiliary measurement circuits during detection and reducing detection costs.

[0005] In a first aspect, the present disclosure provides an insulation impedance detection system for detecting insulation impedance in a photovoltaic hybrid energy system, wherein the photovoltaic hybrid energy system comprises: at least one photovoltaic string, a battery module, at least one first insulation impedance, a second insulation impedance, and an inverter module; the insulation impedance detection system comprises a first auxiliary measurement circuit, a second auxiliary measurement circuit, and a processor; wherein,

[0006] The positive electrode of each photovoltaic string is connected to one end of a first insulation resistor, the positive electrode of the battery module is connected to one end of the second insulation resistor, and the other end of each first insulation resistor and the other end of the second insulation resistor are connected to a reference voltage terminal;

[0007] One end of the first auxiliary measurement circuit is connected to the negative electrode of each photovoltaic string group and the negative electrode of the battery module, one end of the second auxiliary measurement circuit is connected to the positive electrode of the battery module, and the other end of the first auxiliary measurement circuit and the other end of the second auxiliary measurement circuit are connected to the reference voltage terminal;

[0008] The processor is used to control the inverter module to set the output voltage of each group of photovoltaic strings and the bus voltage of the line where the battery module is located, and based on the set voltage, control the first auxiliary measurement circuit and the second auxiliary measurement circuit to detect the voltage of the negative pole of each group of photovoltaic strings and the negative pole of the battery module relative to the reference voltage terminal, and calculate the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance according to the set output voltage and the corresponding detected voltage.

[0009] In a second aspect, the present disclosure provides an insulation impedance detection method, which is used to control an insulation impedance detection system to detect the impedance value of the insulation impedance in a photovoltaic hybrid energy system. The photovoltaic hybrid energy system includes: at least one photovoltaic string, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance, and an inverter module; the insulation impedance detection system includes a first auxiliary measurement circuit and a second auxiliary measurement circuit. The method includes:

[0010] Controlling the inverter module to set the output voltage of each photovoltaic string group and the bus voltage of the circuit where the battery module is located;

[0011] Based on the set voltage, detecting the voltage of the negative electrode of each photovoltaic string group and the negative electrode of the battery module relative to the reference voltage terminal by controlling the first auxiliary measurement circuit and the second auxiliary measurement circuit;

[0012] An impedance value of each of the first insulation resistor, the second insulation resistor, and the third insulation resistor is calculated according to the set output voltage and the corresponding detected voltage.

[0013] In a third aspect, the present disclosure provides a photovoltaic storage hybrid energy system, which includes: at least one set of photovoltaic strings, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance and an inverter module; wherein,

[0014] The positive pole of each photovoltaic string group is connected to one end of a first insulation resistor, the positive pole of the battery module is connected to one end of the second insulation resistor, the other end of each first insulation resistor and the other end of the second insulation resistor are respectively connected to the reference voltage terminal, the negative pole of each photovoltaic string group and the negative pole of the battery module are respectively connected to one end of the third insulation resistor, and the other end of the third insulation resistor is connected to the reference voltage terminal. The inverter module is used to set the output voltage of each photovoltaic string group and the bus voltage of the line where the battery module is located.

[0015] The insulation impedance detection system, method, and photovoltaic-storage hybrid energy system provided in the present disclosure can be used to detect the insulation impedance in the photovoltaic-storage hybrid energy system. The photovoltaic-storage hybrid energy system includes: at least one group of photovoltaic strings, a battery module, at least one first insulation impedance, a second insulation impedance, and an inverter module. The insulation impedance detection system includes a first auxiliary measurement circuit, a second auxiliary measurement circuit, and a processor. The first auxiliary measurement circuit is located between the negative pole of each photovoltaic string group and the negative pole of the battery module and the reference voltage terminal, and the second auxiliary measurement circuit is located between the second insulation impedance and the reference voltage terminal. The inverter module is controlled to set the output voltage of each photovoltaic string group and the bus voltage of the line where the battery module is located. Based on the set voltage, the first auxiliary measurement circuit and the second auxiliary measurement circuit are controlled to detect the voltage of the negative pole of each photovoltaic string group and the negative pole of the battery module relative to the reference voltage terminal, thereby calculating the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance based on the set output voltage and the corresponding detected voltage. In this insulation impedance detection system, for the insulation impedance in the photovoltaic hybrid energy system to be detected, only two auxiliary measurement circuits are needed to detect the insulation impedance of each DC power supply to the ground, which is conducive to simplifying the control of the auxiliary measurement circuits during detection and reducing detection costs.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present disclosure, nor are they intended to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. The above and other features and advantages will become more apparent to those skilled in the art by describing detailed example embodiments with reference to the accompanying drawings. In the accompanying drawings:

[0018] FIG1 is a schematic structural diagram of a photovoltaic-storage hybrid energy system provided in an embodiment of the present disclosure.

[0019] FIG2 is a schematic structural diagram of an insulation impedance detection system provided in an embodiment of the present disclosure.

[0020] FIG3 is a schematic diagram of the detailed structure of the insulation impedance detection system provided by an embodiment of the present disclosure;

[0021] FIG4 is a flow chart of an insulation impedance detection method provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] To enable those skilled in the art to better understand the technical solutions of the present disclosure, exemplary embodiments of the present disclosure are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding. These details should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0023] In the absence of conflict, the various embodiments of the present disclosure and the various features therein may be combined with each other.

[0024] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0025] The terms used herein are only used to describe specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and / or "made of" are used in this specification, features, wholes, steps, operations, elements and / or components are specified to exist, but the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof are not excluded. Similar words such as "connected" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted as having an idealized or overly formal meaning unless expressly defined as such herein.

[0027] In grid-connected photovoltaic power generation technology, the output voltage of photovoltaic cells is relatively high. Because photovoltaic panels are placed outdoors, weather factors such as dust, rain, snow, and fog can affect the insulation between the positive and negative electrodes of the photovoltaic cells and the ground. As a high-voltage system, the quality of the insulation is a key indicator of the safety of photovoltaic grid-connected inverters. Insulation resistance measurement technology can determine the current insulation status of the system and any changes in the insulation status.

[0028] In a photovoltaic system, the insulation resistance of the DC side to ground can indicate the system's insulation performance. If this resistance is too low, the resulting leakage current can pose a threat to personnel. Current safety standards prohibit grid-connected operation when the DC-to-ground insulation resistance falls below a certain value. Therefore, photovoltaic inverters must monitor the insulation resistance of the photovoltaic system.

[0029] Some related technologies provide a multi-input DC power supply insulation impedance detection circuit and method. The detection circuit may include m DC power supplies, each connected to a common negative or positive electrode. If the m DC power supplies are connected to a common negative electrode, a resistor R and a switch are electrically connected in parallel between the negative electrode of the DC power supply and ground. If the m DC power supplies are connected to a common positive electrode, a resistor R and a switch are connected in series between the positive electrode of the DC power supply and ground. This detection circuit cannot individually measure the insulation impedance of each DC power supply (photovoltaic array or battery) to ground.

[0030] In some related technologies, a dual-branch input photovoltaic grid-connected inverter insulation resistance detection system and method can be provided. The system includes: a BOOST circuit 1 for boosting the voltage of a first photovoltaic cell, a BOOST circuit 2 for boosting the voltage of a second photovoltaic cell, a PV1 voltage sampling circuit for sampling the voltage of the first photovoltaic cell, a PV2 voltage sampling circuit for sampling the voltage of the second photovoltaic cell, a lower bridge arm voltage sampling circuit, a resistance switch circuit, and a microprocessor. By utilizing the short-circuit characteristic of the photovoltaic array, the corresponding boost power conversion circuits are controlled to short-circuit PV1+ and PV2+ to PV-, and when the switch in the circuit is closed, the detection voltages in the three situations are detected. According to the circuit law, a three-variable linear equation can be listed to respectively calculate the insulation resistance R1+ of the positive electrode of the first photovoltaic cell to the ground, the insulation resistance R2+ of the positive electrode of the second photovoltaic cell to the ground, and the equivalent parallel insulation resistance R- of the common negative electrode of the first photovoltaic cell and the second photovoltaic cell to the ground. In this detection system, since there is no photovoltaic output at night, this method is not applicable at night and cannot measure the insulation impedance of the battery circuit.

[0031] In some related technologies, a DC power supply to ground insulation resistance detection circuit and its detection method can be provided, including resistors R1-R5 and switches S1-S5. Resistors R1 and R3 have the same resistance value; resistors R2 and R4 have the same resistance value. One end of resistor R2 is connected to the positive pole of the DC power supply via resistor R1, and the other end is grounded via switch S1. Resistors R1, R2 and switch S1 form a first detection branch. One end of resistor R4 is connected to the negative pole of the DC power supply via resistor R3, and the other end is grounded via switch S2. Resistors R3, R4 and switch S2 form a second detection branch; resistor R5 is connected in parallel with the first detection branch or in parallel with the second detection branch. In this system, many switching circuits are required, the control is complex, and the cost is high.

[0032] The embodiments of the present disclosure provide an insulation impedance detection system for detecting insulation impedance in a photovoltaic and energy storage hybrid energy system, which is beneficial for simplifying the control of auxiliary measurement circuits during detection and reducing detection costs.

[0033] Figure 1 shows a schematic diagram of the structure of a photovoltaic-storage hybrid energy system provided by an embodiment of the present disclosure. As shown in Figure 1, the photovoltaic-storage hybrid energy system includes: at least one photovoltaic string, a battery module BAT, at least one first insulation resistor, a second insulation resistor RP2, a third insulation resistor Rn, and an inverter module 110. For example, the photovoltaic strings include a first photovoltaic string PV1 and a second photovoltaic string PV2, and the first insulation resistors include a first insulation resistor RP11 and a first insulation resistor RP12.

[0034] In some embodiments, the positive pole of each photovoltaic string is connected to one end of a first insulation resistor, the positive pole of the battery module is connected to one end of a second insulation resistor, the other end of each first insulation resistor and the other end of the second insulation resistor are respectively connected to the reference voltage terminal, the negative pole of each photovoltaic string and the negative pole of the battery module are respectively connected to one end of a third insulation resistor, and the other end of the third insulation resistor is connected to the reference voltage terminal.

[0035] In Figure 1, exemplarily, the positive pole of the first photovoltaic string PV1 is connected to one end of a first insulation resistor RP11, the positive pole of the second photovoltaic string PV2 is connected to one end of another first insulation resistor RP12, and the other end of the first insulation resistor RP11 and the other end of the first insulation resistor RP12 are respectively connected to the reference voltage terminal PE; the positive pole of the battery module BAT is connected to one end of the second insulation resistor RP2, and the other end of the second insulation resistor RP2 is connected to the reference voltage terminal PE; the negative pole of the first photovoltaic string PV1, the negative pole of the second photovoltaic string PV2, and the negative pole of the battery module BAT are respectively connected to one end of the third insulation resistor Rn, and the other end of the third insulation resistor Rn is connected to the reference voltage terminal PE.

[0036] In this embodiment, the actual voltage of the reference voltage terminal PE can be set according to the operating scenario and requirements of the photovoltaic hybrid energy system. The voltage value of the reference voltage terminal PE can serve as the reference voltage of the photovoltaic hybrid energy system in the embodiment of the present disclosure. That is, the reference voltage of the reference voltage terminal PE can be regarded as relative to 0V. Accordingly, the reference voltage terminal PE can be referred to as the earth or ground.

[0037] In this embodiment, the inverter module 110 is used to set the output voltage of each photovoltaic string group and the bus voltage of the line where the battery module is located.

[0038] In Figure 1, one end of inverter module 110 is connected to the positive terminal of each photovoltaic string and the positive terminal of the battery module, and the other end of inverter module 110 is connected to the power grid. Inverter module 110 is used to convert the DC power of each photovoltaic string and the DC power of the battery module into AC power that meets the requirements of the power grid and then connect the converted AC power to the power grid.

[0039] Figure 1 shows that a hybrid solar-storage energy system includes at least two PV strings and one battery module. In the figure, PV1 and PV2 represent the PV strings, and BAT represents the battery. RP11, RP12, and RP2 represent the equivalent insulation resistance of the positive terminals of PV1, PV2, and BAT to PE, respectively. Rn represents the equivalent insulation resistance of the negative terminals of each DC power source, PV-, to PE.

[0040] It should be understood that FIG1 schematically illustrates only the first photovoltaic string PV1 and the second photovoltaic string PV2 in at least one group of photovoltaic strings. The number of photovoltaic strings can be set according to the actual operating scenario and requirements of the photovoltaic-storage hybrid energy system. Specifically, in the photovoltaic-storage hybrid energy system, each additional photovoltaic string requires a corresponding increase in a first insulation resistor. The positive electrode of the newly added photovoltaic string is connected to one end of the correspondingly increased first insulation resistor, the other end of the correspondingly increased first insulation resistor is connected to the reference voltage terminal, and the negative electrode of the newly added photovoltaic string is connected to one end of the aforementioned third insulation resistor Rn.

[0041] Figure 2 shows a schematic diagram of the insulation impedance detection system provided in an embodiment of the present disclosure. Structures identical or equivalent to those in Figure 1 are numbered the same. In an embodiment of the present disclosure, the insulation impedance detection system is used to detect insulation impedance in a photovoltaic hybrid energy storage system. The insulation impedance detection system includes a first auxiliary measurement circuit F1, a second auxiliary measurement circuit F2, and a processor C1.

[0042] Among them, one end of the first auxiliary measurement circuit F1 is connected to the negative electrode of each photovoltaic string group (for example, photovoltaic strings PV1, PV2) and the negative electrode of the battery module BAT, one end of the second auxiliary measurement circuit F2 is connected to the positive electrode of the battery module, and the other end of the first auxiliary measurement circuit F1 and the other end of the second auxiliary measurement circuit F2 are connected to the reference voltage terminal PE.

[0043] In Figure 2, the processor C1 is used to control the inverter module 110 to set the output voltage of each group of photovoltaic strings (for example, photovoltaic strings PV1, PV2) and the bus voltage of the line where the battery module BAT is located, and based on the set voltage, control the first auxiliary measurement circuit F1 and the second auxiliary measurement circuit F2 to detect the voltage of the negative electrode of each group of photovoltaic strings (for example, photovoltaic strings PV1, PV2) and the negative electrode of the battery module BAT relative to the reference voltage terminal PE, and calculate the impedance value of each first insulation resistor (for example, RP11, RP12) and the impedance value of the second insulation resistor RP2 according to the set output voltage and the corresponding detected voltage.

[0044] In the insulation impedance detection system of this embodiment, for the insulation impedance in the photovoltaic hybrid energy system to be detected, only two auxiliary measurement circuits are needed to detect the insulation impedance of each DC power supply to the ground, which is conducive to simplifying the control of the auxiliary measurement circuits during detection and reducing the detection cost.

[0045] Figure 3 shows a detailed schematic diagram of the insulation impedance detection system provided by an embodiment of the present disclosure. Structures identical or equivalent to those in Figures 2 and 1 are numbered the same. The following describes in detail an insulation impedance detection system according to another embodiment of the present disclosure in conjunction with Figure 3.

[0046] As shown in FIG3 , the inverter module includes at least one first chopper, a second chopper Z2 and an inverter N1; for example, the first chopper includes a first chopper Z11 and a first chopper Z12. In the insulation impedance detection system, the first auxiliary measurement circuit F1 includes a first switching device K1 and a first resistor network R1, and the second auxiliary measurement circuit F2 includes a second switching device K2 and a second resistor network R2; the insulation impedance detection system also includes a first negative sampling point S1. However, the present disclosure is not limited to the specific modules described above and shown in FIG3 . In some embodiments, the photovoltaic hybrid energy system and the insulation impedance detection system may each include only part of the modules therein, that is, the photovoltaic hybrid energy system and the insulation impedance detection system include a more flexible module configuration, which will be explained below in conjunction with specific embodiments.

[0047] In some embodiments, the inverter module includes: at least one first chopper, a second chopper Z2 and an inverter; wherein, one end of each first chopper is respectively connected to the positive pole of a group of photovoltaic strings and one end of a first insulation resistor, and the other end of each first chopper is connected to one end of the inverter; one end of the second chopper is connected to the positive pole of the battery module, and the other end of the second chopper is connected to one end of the inverter; the other end of the inverter is connected to the power grid; the processor is also used to control the DC voltage output by the corresponding photovoltaic string set by each first chopper, and to control the second chopper to set the bus voltage of the line where the battery module is located; the inverter is used to convert the controlled DC voltage of each photovoltaic string and the DC voltage of the battery module into AC voltages that meet the requirements of the power grid.

[0048] As shown in Figure 3, the inverter module 110 includes: a first chopper Z11 and a first chopper Z12, one end of the first chopper Z11 is connected to a group of photovoltaic strings PV1 and a first insulation resistor RP11, one end of another first chopper Z12 is respectively connected to another group of photovoltaic strings PV2 and another first insulation resistor RP12, and the other end of one first chopper Z11 and the other end of the other first chopper Z12 are respectively connected to one end of the inverter N1.

[0049] Continuing with reference to Figure 3, one end of the second chopper Z2 is connected to the positive electrode of the battery module BAT, and the other end of the second chopper Z2 is connected to one end of the inverter N1; the other end of the inverter N1 is connected to the power grid; the processor C1 is further used to control the first chopper Z11 to set the DC voltage output by the photovoltaic string PV1, and is also used to control the first chopper Z12 to set the DC voltage output by the photovoltaic string PV2, and is also used to control the second chopper Z2 to set the bus voltage of the line where the battery module BAT is located; the inverter N1 is used to convert the DC voltage of the photovoltaic string PV1, the DC voltage of the photovoltaic string PV2, and the DC voltage of the battery module BAT into AC voltages that meet the requirements of the power grid.

[0050] Exemplarily, each first chopper, such as first chopper Z11 and first chopper Z12, may be a component that converts direct current (DC) to direct current (DC), also known as a DC / DC converter. A DC / DC converter may refer to a device that converts voltage using direct current. In a DC circuit, a DC / DC converter may convert electrical energy of one voltage value into electrical energy of another voltage value. Exemplarily, second chopper Z2 is a component that converts direct current (DC) to direct current (DC), also known as a DC / DC converter.

[0051] It should be understood that FIG3 only schematically illustrates that the insulation impedance detection system includes the first chopper Z11 and the first chopper Z12, and the number of first choppers can be set according to the number of photovoltaic strings. Specifically, each photovoltaic string group can correspond to one first chopper.

[0052] In this embodiment, each photovoltaic string and battery module in at least one group of photovoltaic strings corresponds to a chopper, and each chopper can be controlled separately by the processor to control the output voltage of each photovoltaic string and the output voltage of the battery module, providing a circuit structure basis for subsequent detection of insulation impedance in the photovoltaic and storage hybrid energy system.

[0053] As shown in FIG3 , in some embodiments, the first auxiliary measurement circuit F1 includes a first switching device K1 and a first resistor network R1, and the second auxiliary measurement circuit F2 includes a second switching device K2 and a second resistor network R2. The insulation impedance detection system further includes a first negative electrode sampling point S1. One end of the first switching device K1 is connected to the negative electrode of each photovoltaic string group (e.g., PV1, PV2) and the negative electrode of the battery module BAT, and the other end of the first switching device K1 is connected to one end of the first resistor network R1, and the other end of the first resistor network R1 is connected to the reference voltage terminal PE. One end of the second switching device K2 is connected to the positive electrode of the battery module, and the other end of the second switching device K2 is connected to one end of the second resistor network R2, and the other end of the second resistor network R2 is connected to the reference voltage terminal PE. The first negative electrode sampling point S1 is connected to the negative electrode of each photovoltaic string group (e.g., PV1, PV2) and the negative electrode of the battery module BAT, as well as the processor C1.

[0054] For example, the first resistor network R1 and the second resistor network R2 may each include a single resistor, or at least two resistors connected in series and / or in parallel. The resistor network form and resistance value of the first resistor network R1 and the resistor network form and resistance value of the second resistor network R2 may be the same or different, and may be specifically set according to actual application scenarios of the insulation impedance detection system.

[0055] In this embodiment, as can be seen from FIG3 , a first auxiliary measurement circuit F1 consisting of a first switch device K1 and a first resistor network R1 is connected between the negative electrode PV- of each photovoltaic string group and the reference voltage terminal PE; a second auxiliary measurement circuit F2 consisting of a second switch device K2 and a second resistor network R2 is connected between the negative electrode of the battery module BAT and the reference voltage terminal PE. The small number of switching loops is conducive to simplifying the circuit structure of the insulation impedance detection system, saving costs, and being able to measure the DC impedance of all photovoltaic input and battery input terminals to ground.

[0056] In some embodiments, the DC voltage of the battery module BAT is a first battery voltage V bat The processor C1 is also used to control the second chopper Z2 so that the bus voltage of the line where the battery module BAT is located is the second battery voltage V bus .

[0057] Each first chopper is controlled so that the DC voltage of the photovoltaic string corresponding to each first chopper (for example, the first chopper Z11 corresponds to the photovoltaic string PV1, and the first chopper Z12 corresponds to the photovoltaic string PV2 in FIG3 ) is the first photovoltaic string voltage corresponding to each photovoltaic string, for example, the first photovoltaic string voltage V corresponding to the first photovoltaic string PV1 is pvla , and the second photovoltaic string voltage V corresponding to the second photovoltaic string PV2 pv2a , and under the condition that the first switch device K1 is closed and the second switch device K2 is opened, the first voltage signal V is collected from the first negative sampling point S1 n1 , and, in the case where the first switch device K1 is controlled to be off and the second switch device K2 is controlled to be closed, a second voltage signal V is collected from the first negative electrode sampling point S1 n2 .

[0058] Each first chopper is controlled so that the DC voltage of the photovoltaic string corresponding to each first chopper is the second photovoltaic string voltage corresponding to each photovoltaic string, for example, the first photovoltaic string voltage V corresponding to the first photovoltaic string PV1 is pv1b , and the first photovoltaic string voltage V corresponding to the second photovoltaic string PV2 pv2b , and under the condition that the first switch device K1 is closed and the second switch device K2 is opened, the third voltage signal V is collected from the first negative sampling point S1 n3 .

[0059] Each first chopper is controlled so that the DC voltage of the photovoltaic string corresponding to each first chopper (for example, the first chopper Z11 corresponds to the photovoltaic string PV1, and the first chopper Z12 corresponds to the photovoltaic string PV2 in FIG3 ) is the third photovoltaic string voltage corresponding to each photovoltaic string, for example, the first photovoltaic string voltage V corresponding to the first photovoltaic string PV1 is V pv1c , and the first photovoltaic string voltage V corresponding to the second photovoltaic string PV2 pv2c , and under the condition that the first switch device is controlled to be closed and the second switch device is opened, a fourth voltage signal V is collected from the first negative electrode sampling point n4 . The first photovoltaic string voltage, the second photovoltaic string voltage and the third photovoltaic string voltage are different voltages;

[0060] The processor C1 is further configured to: bat 、The first photovoltaic string voltage (V pv1a、V pv2a ), the first voltage signal V n1 , the second voltage signal V n2 、Second PV string voltage (V pv1b 、V pv2b ), the third voltage signal V n3 、The third photovoltaic string voltage (V pv1c 、V pv2c ) and the fourth voltage signal V n4 , calculating the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance.

[0061] For example, according to Kirchhoff's law, the following simultaneous equations of expression (1) can be obtained:

[0062] Representing resistance with conductance G, the above formula can be expressed as the following expression (2):

[0063] It is expressed in the matrix form of the following expression (3):

[0064] make:

[0065] That is: AG=B, so we can solve G=A -1 B, where A -1 is the inverse matrix of A.

[0066] It should be understood that if the photovoltaic and storage hybrid energy system includes more photovoltaic strings, the method of insulation detection by the insulation impedance detection system is consistent with the method of insulation detection when the photovoltaic and storage hybrid energy system includes two photovoltaic strings. It is only necessary to establish the corresponding set of simultaneous equations according to Kirchhoff's laws for solution.

[0067] In this embodiment, the DC / DC circuit of each photovoltaic input in the solar-storage hybrid energy system controls the voltage of the photovoltaic strings, and the insulation resistance to ground of each DC input is solved by combining simultaneous equations with other switching circuits. Compared with related technologies, this reduces the number of switching circuits and enables detection of the insulation resistance to ground of each DC power source.

[0068] 3 , in some embodiments, the processor C1 is further configured to: collect a fifth voltage signal V from the first negative electrode sampling point S1 by controlling the switching states of the first switching device K1 and the second switching device K2 while controlling each first chopper (e.g., the first choppers Z11 and Z12 in FIG. 3 ) and the second chopper Z2 to stop working. nand the sixth voltage signal V′ n , and based on the fifth voltage signal V n and the sixth voltage signal V′ n Calculate the total insulation resistance of the photovoltaic storage hybrid energy system V iso ; Processor C1 is also used to calculate the total insulation resistance R iso When the impedance is less than or equal to the predetermined impedance threshold, the second chopper Z2 is controlled to make the bus voltage of the circuit where the battery module BAT is located equal to the second battery voltage V bus .

[0069] In the embodiment of the present disclosure, the processor C1 can change (control) the bus voltage of the line where the battery module BAT is located, that is, the output voltage of the second chopper Z2 or the input voltage of the inverter N1 by controlling the second chopper Z2.

[0070] For example, the total insulation resistance is:

[0071] In the above expression (4), R1 is the resistance value of R1 in the first auxiliary measurement circuit. The meanings of other symbols refer to the description in the above embodiment and are not repeated here.

[0072] In this embodiment, the total insulation impedance of all DC inputs can be first detected by the insulation impedance detection system. When the detected insulation impedance value is lower than the normal value (less than or equal to the predetermined impedance threshold), the insulation impedance of each DC input is then detected by the insulation impedance detection system. This helps to accurately locate which power supply is faulty and facilitates system maintenance. When the detected total insulation impedance meets the requirements (greater than the predetermined impedance threshold), there is no need to detect the impedance of each input again, and the detection is completed quickly, thereby improving detection efficiency.

[0073] In some embodiments, the processor C1 is specifically configured to: when controlling each first chopper (e.g., the first choppers Z11 and Z12 in FIG. 3 ) and the second chopper Z2 to stop working and controlling the second switch device K2 to be disconnected, perform the following steps: control the first switch device K1 to be disconnected, and collect the fifth voltage signal V from the first negative electrode sampling point S1. n ; Control the first switch device K1 to close, and collect and provide the sixth voltage signal v'n from the first negative sampling point S1; according to the collected fifth voltage signal V n and the sixth voltage signal V′ n Calculate the total insulation resistance R of the photovoltaic storage hybrid energy system iso .

[0074] In this embodiment, first, the DC / DC circuits in the photovoltaic hybrid energy system are controlled to stop working, and the second switch device K2 is controlled to be disconnected. Then, the voltages of PV- to PE measured after the first switch device K1 is disconnected and after the first switch device K1 is closed are set to be V n and V′ n , thus according to the detected fifth voltage signal V n and the sixth voltage signal V′ n Calculate the total insulation resistance R of the photovoltaic storage hybrid energy system iso , to determine whether the detected total insulation resistance meets the requirements.

[0075] According to the insulation impedance detection system of the embodiment of the present disclosure, only two auxiliary measurement circuits are required to detect the insulation impedance of each DC power source to ground in the photovoltaic hybrid energy system to be detected. Compared with the related art, the number of switching circuits is reduced, and the insulation impedance of each DC power source to ground is detected, which helps to simplify the control of the auxiliary measurement circuits during detection and reduce detection costs. In addition, the total insulation impedance of all DC inputs can be first detected by the insulation impedance detection system. When the detected insulation impedance value is lower than the normal value (less than or equal to the predetermined impedance threshold), the insulation impedance of each DC input can be measured by the insulation impedance detection system, thereby taking into account both the rapidity of insulation impedance detection and the fault location function. In addition, one end of the battery module is connected to the second chopper, and the second chopper is connected to the power grid through the inverter. At night, in poor lighting conditions, or in the absence of light, insulation impedance detection can still be performed using the insulation impedance detection system of the embodiment of the present disclosure, thereby achieving insulation impedance detection even in the absence of light.

[0076] Figure 4 is a flow chart of an insulation impedance detection method provided in an embodiment of the present disclosure. In some embodiments, the insulation impedance detection method is used to control an insulation impedance detection system to detect the insulation impedance value of a photovoltaic hybrid energy system with energy storage, wherein the photovoltaic hybrid energy system includes: at least one photovoltaic string, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance, and an inverter module; the insulation impedance detection system includes a first auxiliary measurement circuit and a second auxiliary measurement circuit.

[0077] The positive pole of each photovoltaic string is connected to one end of a first insulation resistor, the positive pole of the battery module is connected to one end of a second insulation resistor, the other end of each first insulation resistor and the other end of the second insulation resistor are respectively connected to the reference voltage terminal, the negative pole of each photovoltaic string and the negative pole of the battery module are respectively connected to one end of a third insulation resistor, and the other end of the third insulation resistor is connected to the reference voltage terminal.

[0078] In the description of the method embodiment, the insulation impedance detection system may further include a processor, which may be used to execute the insulation impedance detection method. For the topological structure of the insulation impedance detection system and the photovoltaic hybrid energy system involved in this embodiment, please refer to the insulation impedance detection system and the photovoltaic hybrid energy system of the embodiment of the present disclosure described in combination with Figures 1-3 above, and will not be repeated here.

[0079] As shown in FIG4 , in some embodiments, the insulation impedance detection method includes:

[0080] S410, controlling the inverter module to set the output voltage of each photovoltaic string group and the bus voltage of the line where the battery module is located;

[0081] S420, based on the set voltage, detecting the voltage of the negative electrode of each photovoltaic string and the negative electrode of the battery module relative to the reference voltage terminal by controlling the first auxiliary measurement circuit and the second auxiliary measurement circuit;

[0082] S430 , calculating an impedance value of each first insulation impedance, an impedance value of the second insulation impedance, and an impedance value of the third insulation impedance according to the set output voltage and the corresponding detected voltage.

[0083] Through the above steps S410-S430, the output voltage of each photovoltaic string group and the bus voltage of the line where the battery module is located can be set by controlling the inverter module. Based on the set voltage, the first auxiliary measurement circuit and the second auxiliary measurement circuit are controlled to detect the voltage of the negative electrode of each photovoltaic string group and the negative electrode of the battery module relative to the reference voltage terminal, thereby calculating the impedance value of each first insulation resistance, the impedance value of the second insulation resistance, and the impedance value of the third insulation resistance based on the set output voltage and the corresponding detected voltage. The insulation impedance detection system based on this method only requires two auxiliary measurement circuits to detect the insulation impedance of each DC power supply to ground in the photovoltaic hybrid energy system to be detected, which helps to simplify the control of the auxiliary measurement circuits during detection and reduce detection costs.

[0084] In some embodiments, the inverter module includes at least one first chopper, a second chopper and an inverter; step S410 may specifically include: controlling the second chopper to set the bus voltage of the line where the battery module is located; and controlling each first chopper to set the DC voltage output by the corresponding photovoltaic string.

[0085] In this embodiment, the processor can control each first chopper and the second chopper separately to collect the corresponding voltage signals during the detection process according to the bus voltage of the circuit where the battery module is located and the DC voltage output by the set photovoltaic string, thereby providing a data basis for the subsequent calculation of the insulation impedance of each DC power supply to the ground.

[0086] In some embodiments, the first auxiliary measurement circuit includes a first switching device and a first resistor network, and the second auxiliary measurement circuit includes a second switching device and a second resistor network; the insulation impedance detection system also includes a first negative electrode sampling point; and the DC voltage of the battery module is a first battery voltage.

[0087] In this embodiment, step S420 may specifically include the following steps.

[0088] S11, controlling the second chopper so that the bus voltage of the circuit where the battery module is located is equal to the second battery voltage;

[0089] S12, controlling each first chopper so that the DC voltage of the photovoltaic string corresponding to each first chopper is the first photovoltaic string voltage corresponding to each photovoltaic string, and collecting a first voltage signal from the first negative electrode sampling point when the first switching device is controlled to be closed and the second switching device is controlled to be open, and collecting a second voltage signal from the first negative electrode sampling point when the first switching device is controlled to be open and the second switching device is controlled to be closed;

[0090] S13, controlling each first chopper so that the DC voltage of the photovoltaic string corresponding to each first chopper is the second photovoltaic string voltage corresponding to each photovoltaic string, and collecting a third voltage signal from the first negative electrode sampling point when controlling the first switching device to be closed and the second switching device to be open;

[0091] S14: Control each first chopper so that the DC voltage of the photovoltaic string corresponding to each first chopper is the third photovoltaic string voltage corresponding to each photovoltaic string, and collect a fourth voltage signal from the first negative sampling point while controlling the first switching device to be closed and the second switching device to be open. The first photovoltaic string voltage, the second photovoltaic string voltage, and the third photovoltaic string voltage may be different voltages.

[0092] In this embodiment, step S430 may specifically include: calculating the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance based on the first battery voltage, the first photovoltaic string voltage, the first voltage signal, the second voltage signal, the second photovoltaic string voltage, the third voltage signal, the third photovoltaic string voltage, and the fourth voltage signal.

[0093] In this step, the specific process of calculating the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance based on Kirchhoff's law can refer to the above expressions (1)-(3), which will not be repeated here.

[0094] In this embodiment, the DC / DC circuit of each photovoltaic input in the solar-storage hybrid energy system controls the voltage of the photovoltaic strings, and the insulation resistance to ground of each DC input is solved by combining simultaneous equations with other switching circuits. Compared with related technologies, this reduces the number of switching circuits and enables detection of the insulation resistance to ground of each DC power source.

[0095] In some embodiments, the step of controlling the second chopper in step S11 so that the bus voltage of the circuit where the battery module is located is the second battery voltage can specifically include: while controlling each of the first chopper and the second chopper to stop working, by controlling the switching states of the first switching device and the second switching device, collecting the fifth voltage signal and the sixth voltage signal from the first negative electrode sampling point, and calculating the impedance value of the total insulation impedance of the photovoltaic hybrid energy system based on the fifth voltage signal and the sixth voltage signal; when the total insulation impedance is less than or equal to the predetermined impedance threshold, controlling the second chopper to make the bus voltage of the circuit where the battery module is located the second battery voltage.

[0096] In this embodiment, the total insulation impedance of all DC inputs can be first detected by the insulation impedance detection system. When the detected insulation impedance value is lower than the normal value (less than or equal to the predetermined impedance threshold), the insulation impedance of each DC input is then detected by the insulation impedance detection system. This helps to accurately locate which power supply is faulty and facilitates system maintenance. When the detected total insulation impedance meets the requirements (greater than the predetermined impedance threshold), there is no need to detect the impedance of each input again, and the detection is completed quickly, thereby improving detection efficiency.

[0097] In some embodiments, the step of collecting the fifth voltage signal and the sixth voltage signal from the first negative electrode sampling point by controlling the switching states of the first switching device and the second switching device may specifically include: collecting the fifth voltage signal from the first negative electrode sampling point when the second switching device is controlled to be disconnected and the first switching device is disconnected; and collecting and providing the sixth voltage signal from the first negative electrode sampling point when the second switching device is controlled to be disconnected and the first switching device is closed.

[0098] In this embodiment, by controlling the internal chopper (DC / DC circuit) of the photovoltaic and storage hybrid energy system to stop working, and by controlling the switching states of the first switching device and the second switching device, the fifth voltage signal and the sixth voltage signal are collected from the first negative electrode sampling point, and the impedance value of the total insulation impedance of the photovoltaic and storage hybrid energy system is calculated based on the detected fifth voltage signal and sixth voltage signal to determine whether the detected total insulation impedance meets the requirements.

[0099] According to the insulation impedance detection method of the embodiment of the present disclosure, for the insulation impedance in the photovoltaic hybrid energy system to be detected, only two auxiliary measurement circuits are needed to detect the insulation impedance of each DC power supply to the ground. Compared with the related art, the number of switching circuits is reduced, and the insulation impedance of each DC power supply to the ground is detected, which is conducive to simplifying the control of the auxiliary measurement circuit during detection and reducing the detection cost; moreover, the total insulation impedance of all DC inputs can be detected first, and when the detected insulation impedance value is lower than the normal value (less than or equal to the predetermined impedance threshold), the insulation impedance of each DC input is then detected, thereby taking into account the rapidity of insulation impedance detection and the fault location function; and one end of the battery module is connected to the second chopper, and the second chopper is connected to the power grid through the inverter. At night, in poor lighting or in the absence of light, insulation impedance detection can still be performed, so that insulation impedance can be detected even in the absence of light.

[0100] The insulation impedance detection method according to the embodiment of the present disclosure can be executed by an electronic device with control and computing capabilities, such as a processor. The terminal device can be a user equipment (UE), a mobile device, a user terminal, a terminal, a personal digital assistant (PDA), a handheld device, a computing device, etc. The method can be implemented by the processor calling computer-readable program instructions stored in a memory. The server can include an independent physical server, a server cluster consisting of multiple servers, or a cloud server capable of cloud computing.

[0101] It is understood that the above-mentioned various method embodiments mentioned in this disclosure can be combined with each other to form combined embodiments without violating the principle logic. Due to space limitations, this disclosure will not go into details. It is understood by those skilled in the art that in the above-mentioned methods of specific implementation, the specific execution order of each step should be determined by its function and possible internal logic.

[0102] It should be understood that the present disclosure is not limited to the specific configurations and processes described in the above embodiments and illustrated in the figures. For the sake of convenience and brevity, detailed descriptions of known methods are omitted here. The specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0103] It will be understood by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In a hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable storage medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium).

[0104] As is well known to those skilled in the art, the term computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information (such as computer-readable program instructions, data structures, program modules or other data). Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technology, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, as is well known to those skilled in the art, communication media typically contains computer-readable program instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0105] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to be stored in the computer-readable storage medium in each computing / processing device.

[0106] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, and conventional procedural programming languages ​​such as "C" language or similar programming languages. Computer-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., utilizing an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be personalized by utilizing the state information of the computer-readable program instructions. The electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0107] The computer program product described herein may be implemented in hardware, software, or a combination thereof. In one embodiment, the computer program product is implemented as a computer storage medium. In another embodiment, the computer program product is implemented as a software product, such as a software development kit (SDK).

[0108] Various aspects of the present disclosure are described herein with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It should be understood that each block of the flowcharts and / or block diagrams, and combinations of blocks in the flowcharts and / or block diagrams, can be implemented by computer-readable program instructions.

[0109] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device is generated that implements the functions / actions specified in one or more blocks in the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, where these instructions cause the computer, programmable data processing device, and / or other device to operate in a specific manner. Thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing various aspects of the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0110] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operational steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more blocks in the flowchart and / or block diagram.

[0111] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and the part of the module, program segment or instruction contains one or more executable instructions for realizing the prescribed logical function. In some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the prescribed function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0112] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted only in a general illustrative sense and not for purposes of limitation. In some instances, it will be apparent to those skilled in the art that, unless otherwise expressly indicated, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments. Therefore, it will be understood by those skilled in the art that various changes in form and detail may be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

1. An insulation impedance detection system, characterized in that, For detecting the insulation impedance in a photovoltaic - energy - storage hybrid energy system, the photovoltaic - energy - storage hybrid energy system includes: at least one set of photovoltaic strings, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance, and an inverter module. The insulation impedance detection system includes a first auxiliary measurement circuit, a second auxiliary measurement circuit, and a processor; wherein, The positive pole of each set of photovoltaic strings is connected to one end of a first insulation impedance, the positive pole of the battery module is connected to one end of the second insulation impedance, the other ends of each first insulation impedance and the second insulation impedance are respectively connected to a reference reference voltage terminal, the negative poles of each set of photovoltaic strings and the negative pole of the battery module are respectively connected to one end of the third insulation impedance, and the other end of the third insulation impedance is connected to the reference reference voltage terminal; One end of the first auxiliary measurement circuit is connected to the negative poles of each set of photovoltaic strings and the negative pole of the battery module, one end of the second auxiliary measurement circuit is connected to the positive pole of the battery module, and the other end of the first auxiliary measurement circuit and the other end of the second auxiliary measurement circuit are connected to the reference reference voltage terminal; The processor is used to control the inverter module to set the output voltage of each set of photovoltaic strings and the bus voltage of the line where the battery module is located, and based on the set voltages, control the first auxiliary measurement circuit and the second auxiliary measurement circuit to detect the voltages of the negative poles of each set of photovoltaic strings and the negative pole of the battery module with respect to the reference reference voltage terminal, and calculate the impedance values of each first insulation impedance, the second insulation impedance, and the third insulation impedance according to the set output voltage and the corresponding detected voltages.

2. The insulation impedance detection system according to claim 1, wherein The inverter module includes: at least one first chopper, a second chopper, and an inverter; wherein, One end of each first chopper is respectively connected to the positive pole of a set of photovoltaic strings and one end of a first insulation impedance The other end of each first chopper is connected to one end of the inverter; one end of the second chopper is connected to the positive pole of the battery module, and the other end of the second chopper is connected to one end of the inverter; the other end of the inverter is connected to the power grid; The processor is also used to control each first chopper to set the DC voltage output by the corresponding photovoltaic string, and control the second chopper to set the bus voltage of the line where the battery module is located; The inverter is used to convert the DC voltages of each controlled photovoltaic string and the battery module into AC voltages respectively.

3. The insulation impedance detection system according to claim 2, characterized in that, The first auxiliary measurement circuit includes a first switching device and a first resistor network, and the second auxiliary measurement circuit includes a second switching device and a second resistor network; The insulation impedance detection system further includes a first negative - pole sampling point; Wherein, one end of the first switching device is respectively connected to the negative poles of each set of photovoltaic strings and the negative pole of the battery module, the other end of the first switching device is connected to one end of the first resistor network, and the other end of the first resistor network is connected to the reference reference voltage terminal; One end of the second switching device is connected to the positive electrode of the battery module, the other end of the second switching device is connected to one end of the second resistor network, and the other end of the second resistor network is connected to the reference reference voltage terminal; One end of the first negative electrode sampling point is connected to the negative electrode of each photovoltaic string and the negative electrode of the battery module, and the other end of the first negative electrode sampling point is connected to the processor.

4. The insulation impedance detection system according to claim 3, wherein The DC voltage of the battery module is the first battery voltage; the processor is further configured to control the second chopper so that the bus voltage of the line where the battery module is located is the second battery voltage; Control each of the first choppers so that the DC voltage of the photovoltaic string corresponding to each first chopper is the first photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a first voltage signal from the first negative electrode sampling point, and, when controlling the first switching device to be open and the second switching device to be closed, collect a second voltage signal from the first negative electrode sampling point; Control each of the first choppers so that the DC voltage of the photovoltaic string corresponding to each first chopper is the second photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a third voltage signal from the first negative electrode sampling point; Control each of the first choppers so that the DC voltage of the photovoltaic string corresponding to each first chopper is the third photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a fourth voltage signal from the first negative electrode sampling point; wherein, the first photovoltaic string voltage, the second photovoltaic string voltage and the third photovoltaic string voltage are different voltages; The processor is further configured to calculate the impedance values of each first insulation impedance, the impedance value of the second insulation impedance and the impedance value of the third insulation impedance based on the first battery voltage, the first photovoltaic string voltage, the first voltage signal, the second voltage signal, the second photovoltaic string voltage, the third voltage signal, the third photovoltaic string voltage and the fourth voltage signal.

5. The insulation impedance detection system according to claim 4, wherein The processor is further configured to: when controlling each of the first choppers and the second chopper to stop working, collect a fifth voltage signal and a sixth voltage signal from the first negative electrode sampling point by controlling the switching states of the first switching device and the second switching device, and calculate the impedance value of the total insulation impedance of the photovoltaic-storage hybrid energy system based on the fifth voltage signal and the sixth voltage signal; The processor is further configured to control the second chopper so that the bus voltage of the line where the battery module is located is the second battery voltage when the impedance value of the total insulation impedance is less than or equal to a predetermined impedance threshold.

6. The insulation impedance detection system according to claim 5, characterized in that The processor is further configured to: When controlling each of the first choppers and the second chopper to stop working, and controlling the second switching device to disconnect and the first switching device to disconnect, the fifth voltage signal is collected from the first negative sampling point; When controlling each of the first choppers and the second chopper to stop working, and controlling the second switching device to disconnect and the first switching device to close, the sixth voltage signal is provided and collected from the first negative sampling point; Calculate the impedance value of the total insulation impedance of the photovoltaic-battery hybrid energy system according to the collected fifth voltage signal and the sixth voltage signal.

7. An insulation impedance detection method, characterized in that, Used to control an insulation impedance detection system to detect the impedance value of the insulation impedance in a photovoltaic-battery hybrid energy system, the photovoltaic-battery hybrid energy system includes: at least one group of photovoltaic strings, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance, and an inverter module; the insulation impedance detection system includes a first auxiliary measurement circuit and a second auxiliary measurement circuit, wherein, the positive electrode of each group of photovoltaic strings is connected to one end of a first insulation impedance, the positive electrode of the battery module is connected to one end of the second insulation impedance, the other ends of each first insulation impedance and the second insulation impedance are respectively connected to a reference reference voltage terminal, the negative electrodes of each group of photovoltaic strings and the negative electrode of the battery module are respectively connected to one end of the third insulation impedance, and the other end of the third insulation impedance is connected to the reference reference voltage terminal; the method includes: Control the inverter module to set the output voltage of each group of photovoltaic strings and the bus voltage of the line where the battery module is located; Based on the set voltage, by controlling the first auxiliary measurement circuit and the second auxiliary measurement circuit, detect the electricity of the negative electrodes of each group of photovoltaic strings and the battery module with respect to the reference reference voltage terminal voltage; Calculate the impedance value of each first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance according to the set output voltage and the corresponding detected voltage.

8. The method according to claim 7, characterized in that The inverter module includes at least one first chopper, a second chopper, and an inverter; controlling the inverter module to set the output voltage of each group of photovoltaic strings and the bus voltage of the line where the battery module is located includes: Control the second chopper to set the bus voltage of the line where the battery module is located; and, Control each first chopper to set the DC voltage output by the corresponding photovoltaic string.

9. The method according to claim 8, wherein The first auxiliary measurement circuit includes a first switching device and a first resistor network, the second auxiliary measurement circuit includes a second switching device and a second resistor network; the insulation impedance detection system further includes a first negative sampling point; the DC voltage of the battery module is the first battery voltage; Wherein, the detecting the voltages of the negative electrodes of each group of photovoltaic strings and the battery module with respect to the reference reference voltage terminal by controlling the first auxiliary measurement circuit and the second auxiliary measurement circuit based on the set voltage includes: Control the second chopper so that the bus voltage of the line where the battery module is located is the second battery voltage; Control each of the first choppers such that the DC voltage of the corresponding photovoltaic string of each first chopper is the first photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a first voltage signal from the first negative sampling point, and, when controlling the first switching device to be open and the second switching device to be closed, collect a second voltage signal from the first negative sampling point; Control each of the first choppers such that the DC voltage of the corresponding photovoltaic string of each first chopper is the second photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a third voltage signal from the first negative sampling point; Control each of the first choppers such that the DC voltage of the corresponding photovoltaic string of each first chopper is the third photovoltaic string voltage corresponding to each photovoltaic string, and when controlling the first switching device to be closed and the second switching device to be open, collect a fourth voltage signal from the first negative sampling point; wherein, the first photovoltaic string voltage, the second photovoltaic string voltage, and the third photovoltaic string voltage are different voltages; Calculating the impedance value of each of the first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance according to the set output voltage and the corresponding detected voltage, includes: calculating the impedance value of each of the first insulation impedance, the impedance value of the second insulation impedance, and the impedance value of the third insulation impedance based on the first battery voltage, the first photovoltaic string voltage, the first voltage signal, the second voltage signal, the second photovoltaic string voltage, the third voltage signal, the third photovoltaic string voltage, and the fourth voltage signal.

10. The method according to claim 9, characterized in that Controlling the second chopper such that the bus voltage of the line where the battery module is located is the second battery voltage, includes: When controlling both the first choppers and the second chopper to stop working, by controlling the switching states of the first switching device and the second switching device, collect a fifth voltage signal and a sixth voltage signal from the first negative sampling point, and calculate the impedance value of the total insulation impedance of the photovoltaic-storage hybrid energy system based on the fifth voltage signal and the sixth voltage signal; When the total insulation impedance is less than or equal to a predetermined impedance threshold, control the second chopper such that the bus voltage of the line where the battery module is located is the second battery voltage.

11. The method according to claim 10, wherein The collecting a fifth voltage signal and a sixth voltage signal from the first negative sampling point by controlling the switching states of the first switching device and the second switching device, includes: When controlling the second switching device to be open and the first switching device to be open, collect a fifth voltage signal from the first negative sampling point; When controlling the second switching device to be open and the first switching device to be closed, collect a sixth voltage signal provided from the first negative sampling point.

12. A hybrid solar and energy storage system, characterized in that, The described photovoltaic and energy storage hybrid system includes: at least one group of photovoltaic strings, a battery module, at least one first insulation impedance, a second insulation impedance, a third insulation impedance, and an inverter module; wherein, the positive electrode of each group of photovoltaic strings is connected to one end of a first insulation impedance, the positive electrode of the battery module is connected to one end of the second insulation impedance, the other ends of each first insulation impedance and the second insulation impedance are respectively connected to a reference reference voltage terminal, the negative electrodes of each group of photovoltaic strings and the battery module are respectively connected to one end of the third insulation impedance, the other end of the third insulation impedance is connected to the reference reference voltage terminal, and the inverter module is used to set the output voltage of each group of photovoltaic strings and the bus voltage of the line where the battery module is located.

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