Insulation resistance detection circuit, energy storage power supply circuit and energy storage equipment

Abstract

The invention belongs to the technical field of circuits, and provides an insulation resistance detection circuit, an energy storage power supply circuit and energy storage equipment. The insulation resistance detection circuit of the energy storage power supply circuit comprises a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a first resistor unit, a second resistor unit, a third resistor unit, a fourth resistor unit and a control unit. The control unit is connected with the five switch units, switches off the fifth switch unit after receiving a first detection instruction, adjusts other switch units, and then obtains voltage values of the positive and negative DC buses to the ground. The ratio of the two insulation resistors is calculated through the values, and if the ratio exceeds a preset threshold value, the system sends out an insulation alarm signal, so that whether the insulation resistors meet requirements or not can be quickly detected, the calculation steps are greatly simplified, and the calculation precision can be improved.

Description

Technical Field

[0001] The present application belongs to the field of circuit technology, and in particular relates to an insulation resistance detection circuit, an energy storage power supply circuit and an energy storage device. Background Art

[0002] The cabinet of the energy storage equipment is usually directly accessible to users, and the energy storage cabinet ground is isolated from the energy storage power supply circuit inside it, in order to prevent people from getting electric shock. However, due to factors such as equipment aging or harsh operating environment, the energy storage power supply circuit may form a leakage circuit to the energy storage cabinet ground, thereby endangering personal safety. Therefore, it is necessary to monitor the insulation of the energy storage power supply circuit in real time.

[0003] Traditional monitoring methods usually use a bridge passive DC method for measurement, but this method takes a long time to measure and the detection accuracy is not high enough. Therefore, how to design a detection circuit that can accurately detect whether the insulation resistance value meets the requirements has become an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present application is to provide an insulation resistance detection circuit, an energy storage power supply circuit and an energy storage device, aiming to solve the problem that the existing insulation resistance detection method has a long measurement time and the detection accuracy is not high enough.

[0005] A first aspect of an embodiment of the present application provides an insulation resistance detection circuit of an energy storage power supply circuit, wherein the energy storage power supply circuit comprises: a DC conversion circuit and an AC conversion circuit, wherein the input end of the DC conversion circuit is used to be connected to a DC power supply, and the output end of the DC conversion circuit is connected to a DC bus; the input end of the AC conversion circuit is used to be connected to a photovoltaic module, and the output end of the AC conversion circuit is connected to the DC bus;

[0006] The insulation resistance detection circuit comprises: a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a first resistor unit, a second resistor unit, a third resistor unit, a fourth resistor unit and a control unit; the first resistor unit and the second switch unit are connected in series, connected between the first end of the first switch unit and the positive DC bus, and the second end of the first switch unit is grounded; the second resistor unit and the third switch unit are connected in series, connected between the negative DC bus and the first end of the first switch unit; the third resistor unit and the fourth switch unit are connected in series, connected between the first end of the first switch unit and the positive DC bus; the fourth resistor unit and the fifth switch unit are connected in series, connected between the negative DC bus and the first end of the first switch unit;

[0007] The control unit is connected to the first switch unit, the second switch unit, the third switch unit, the fourth switch unit and the fifth switch unit; the control unit is used to control the fifth switch unit to be disconnected when receiving the first detection instruction, and control the working states of the first switch unit, the second switch unit, the third switch unit and the fourth switch unit, and obtain the voltage values ​​of the positive DC bus relative to the ground terminal and the negative DC bus relative to the ground terminal under different working states;

[0008] The control unit is also used to calculate a first ratio of the first insulation resistance to the second insulation resistance based on the voltage values ​​of the positive DC bus relative to the ground terminal and the negative DC bus relative to the ground terminal under different working conditions, and generate an insulation alarm signal when the first ratio exceeds a preset insulation value.

[0009] In one embodiment, the step of obtaining voltage values ​​of the positive DC bus relative to the ground terminal and the negative DC bus relative to the ground terminal in different working states includes:

[0010] When receiving the first detection instruction, the control unit controls the fifth switch unit to be disconnected, and controls the first switch unit, the second switch unit, and the third switch unit to be closed; obtains a first voltage value of the positive DC bus relative to the ground terminal, and obtains a second voltage value of the negative DC bus relative to the ground terminal;

[0011] The control unit controls the fourth switch unit to close, obtains a third voltage value of the positive DC bus relative to the ground, and obtains a fourth voltage value of the negative DC bus relative to the ground.

[0012] In one embodiment, the control unit is further configured to control the first switch unit, the fourth switch unit, and the fifth switch unit to be disconnected, and control the second switch unit and the third switch unit to be closed upon receiving the second detection instruction;

[0013] Acquire a fifth voltage value of the positive DC bus relative to the ground terminal, and acquire a sixth voltage value of the negative DC bus relative to the ground terminal;

[0014] The control unit is further configured to calculate a second voltage ratio between the first insulation resistance and the second insulation resistance according to the fifth voltage value and the sixth voltage value.

[0015] In one embodiment, the control unit is further configured to, upon receiving the second detection instruction, control the first switch unit, the second switch unit, and the third switch unit to be disconnected, and control the fourth switch unit and the fifth switch unit to be closed after a first delay time.

[0016] Acquire a seventh voltage value of the positive DC bus relative to the ground terminal, and acquire an eighth voltage value of the negative DC bus relative to the ground terminal;

[0017] The control unit is further configured to calculate a third ratio of the first insulation resistance to the second insulation resistance according to the seventh voltage value and the eighth voltage value.

[0018] In one embodiment, the control unit is further configured to generate the insulation alarm signal when the second ratio and / or the third ratio exceeds the preset insulation value.

[0019] In one embodiment, the insulation resistance detection circuit further includes: a first voltage source, a fifth resistance unit and a sixth switch unit;

[0020] The first voltage source, the fifth resistor unit and the sixth switch unit are sequentially connected in series and then connected in parallel with the first switch unit;

[0021] The control unit is further used to, after receiving the third detection instruction, control the first switch unit, the second switch unit, the fourth switch unit, and the fifth switch unit to be disconnected, control the third switch unit and the sixth switch unit to be closed, control the first voltage source to be at the first level; obtain the ninth voltage value across the second resistor unit; control the first voltage source to be at the second level; and obtain the tenth voltage value across the second resistor unit;

[0022] After the second delay time, the first switch unit, the third switch unit, the fourth switch unit, and the fifth switch unit are all controlled to be disconnected, the second switch unit and the sixth switch unit are all controlled to be closed, and the first voltage source is controlled to be at the first level; an eleventh voltage value across the first resistor is obtained; the first voltage source is controlled to be at the second level; and a twelfth voltage value across the first resistor is obtained;

[0023] The control unit is also used to calculate a fourth ratio of the first insulation resistance to the second insulation resistance based on the ninth voltage value, the tenth voltage value, the eleventh voltage value, and the twelfth voltage value, and generate the insulation alarm signal when the fourth ratio exceeds the preset insulation value.

[0024] In one embodiment, the control unit is further configured to disconnect the DC conversion circuit and the AC conversion circuit when the insulation alarm signal is generated.

[0025] In one embodiment, the sum of the resistance values ​​of the third resistance unit and the fourth resistance unit is greater than the sum of the resistance values ​​of the first resistance unit and the second resistance unit.

[0026] A second aspect of the embodiment of the present application further provides an energy storage power supply circuit, the energy storage power supply circuit comprising:

[0027] A DC conversion circuit, wherein the input end of the DC conversion circuit is used to be connected to a DC power supply, and the output end of the DC conversion circuit is connected to a DC bus;

[0028] An AC conversion circuit, wherein the input end of the AC conversion circuit is used to be connected to a photovoltaic module, and the output end of the AC conversion circuit is connected to the DC bus;

[0029] An intelligent gateway circuit is arranged on the DC bus;

[0030] An insulation resistance detection circuit as described in any one of the above items.

[0031] A third aspect of an embodiment of the present application further provides an energy storage device, characterized in that it includes the energy storage power supply circuit as described above.

[0032] By adopting the above technical solution, the control unit automatically disconnects the fifth switch unit after receiving the first detection instruction to ensure the measurement environment of other switches. Then the states of the first to fourth switch units are gradually adjusted to collect the voltage data of the positive and negative DC bus bars relative to the ground. These values ​​are input into the internal algorithm module to calculate the ratio of the insulation resistance. Once it is detected that the ratio exceeds the safety threshold set by the system, an alarm signal will be immediately displayed on the system interface, and a notification will be sent to the maintenance team through the networked remote monitoring system. By adopting this technical solution, it is possible to quickly detect whether the insulation resistance meets the requirements, greatly simplify the calculation steps, and improve the calculation accuracy, so as to ensure that the insulation performance of the energy storage power supply circuit is within a safe range and prevent potential risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of an insulation resistance detection circuit of an energy storage power supply circuit provided in an embodiment of the present application Figure 1 ;

[0034] Figure 2 A schematic diagram of the structure of an insulation resistance detection circuit of an energy storage power supply circuit provided in an embodiment of the present application Figure 2 ;

[0035] Figure 3 A specific circuit diagram of an insulation resistance detection circuit of an energy storage power supply circuit provided in one embodiment of the present application;

[0036] Figure 4 A schematic diagram of the structure of an energy storage power supply circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0038] It should be noted that the terms "first" and "second" in the specification, claims and drawings of the present application are used to distinguish similar objects rather than to describe a specific order or sequence.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0041] Some embodiments will be described below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0042] The cabinet of the energy storage equipment is usually directly accessible to users, and the energy storage cabinet ground is isolated from the energy storage power supply circuit inside it, in order to prevent people from getting electric shock. However, due to factors such as equipment aging or harsh operating environment, the energy storage power supply circuit may form a leakage circuit to the energy storage cabinet ground, thereby endangering personal safety. Therefore, it is necessary to monitor the insulation of the energy storage power supply circuit in real time.

[0043] Traditional monitoring methods usually use a bridge passive DC method for measurement, but this method takes a long time to measure and the detection accuracy is not high enough. Therefore, how to design a detection circuit that can accurately detect whether the insulation resistance value meets the requirements has become an urgent problem to be solved.

[0044] In order to solve the above technical problems, refer to Figure 1As shown, an embodiment of the present application provides an insulation resistance detection circuit for an energy storage power supply circuit, the energy storage power supply circuit comprising: a DC conversion circuit 100 and an AC conversion circuit 200, the input end of the DC conversion circuit 100 is used to be connected to a DC power supply 300, and the output end of the DC conversion circuit 100 is connected to a DC bus (BUS); the input end of the AC conversion circuit 200 is used to be connected to a photovoltaic module 400, and the output end of the AC conversion circuit 200 is connected to the DC bus.

[0045] The insulation resistance detection circuit includes: a first switch unit 11, a second switch unit 12, a third switch unit 13, a fourth switch unit 14, a fifth switch unit 15, a first resistor unit 21, a second resistor unit 22, a third resistor unit 23, a fourth resistor unit 24 and a control unit 41. The first resistor unit 21 and the second switch unit 12 are connected in series, connected between the first end of the first switch unit 11 and the positive DC bus BUS+, and the second end of the first switch unit 11 is grounded; the second resistor unit 22 and the third switch unit 13 are connected in series, connected between the negative DC bus BUS- and the first end of the first switch unit 11; the third resistor unit 23 and the fourth switch unit 14 are connected in series, connected between the first end of the first switch unit 11 and the positive DC bus BUS+; the fourth resistor unit 24 and the fifth switch unit 15 are connected in series, connected between the negative DC bus BUS- and the first end of the first switch unit 11.

[0046] Specifically, the control unit 41 is connected to the control ends of the first switch unit 11, the second switch unit 12, the third switch unit 13, the fourth switch unit 14 and the fifth switch unit 15; the control unit 41 is used to control the fifth switch unit 15 to disconnect when receiving the first detection instruction, and control the working states of the first switch unit 11, the second switch unit 12, the third switch unit 13 and the fourth switch unit 14, and obtain the voltage values ​​of the positive DC bus BUS+ relative to the ground and the negative DC bus BUS- relative to the ground in different working states.

[0047] In addition, the control unit 41 is also used to calculate a first ratio of the first insulation resistance and the second insulation resistance according to the voltage values ​​of the positive DC bus BUS+ relative to the ground and the negative DC bus BUS- relative to the ground in different working conditions, and generate an insulation alarm signal when the first ratio exceeds a preset insulation value.

[0048] In this embodiment, the energy storage power supply circuit is intended to efficiently integrate multiple power sources to improve power supply stability and efficiency. The circuit system mainly includes: a DC conversion circuit 100 and an AC conversion circuit 200.

[0049] For example, the input end of the DC conversion circuit 100 is usually connected to a traditional power grid, an energy storage battery or other DC power supply equipment, and its output end is connected to a DC bus. Its function is to convert the electrical energy from the power grid and the energy storage battery into a suitable DC power, and provide a stable voltage output to support the normal operation of the DC load. The DC conversion circuit 100 usually also includes a voltage control module to ensure that the output current and voltage are within a controllable range.

[0050] Exemplarily, the input end of the AC conversion circuit 200 is connected to the photovoltaic module 400 to convert solar energy into electrical energy. The photovoltaic module 400 usually provides direct current, but the AC conversion circuit 200 may be combined with the function of an inverter to convert direct current into alternating current and further connect it to the DC bus to adapt to different forms of power requirements in the system.

[0051] In some embodiments, this energy storage power supply circuit is used to manage and optimize the use of energy. For example, during the day, the photovoltaic assembly 400 (such as a rooftop solar panel) converts solar energy into electricity through the AC conversion circuit 200, directly supplies the DC bus, and stores it in the battery module in the system for use at night or on cloudy days. The controller in the system dynamically adjusts the working state of the two conversion circuits according to the changes in household electricity demand, light intensity, and electricity price signals to optimize energy costs and electricity efficiency.

[0052] In this embodiment, the insulation resistance detection circuit provided in the embodiment of the present application can be applied to the energy storage power supply circuit of the above embodiment. Through the insulation resistance detection circuit, it is possible to accurately detect whether the insulation resistance of the DC bus to the ground terminal meets the requirements.

[0053] It should be noted that the first switch unit 11, the second switch unit 12, the third switch unit 13, the fourth switch unit 14, and the fifth switch unit 15 may include switch devices such as switch tubes and relays, and the switch tube may be, for example, a triode or a field effect tube. The first resistor unit 21, the second resistor unit 22, the third resistor unit 23, and the fourth resistor unit 24 may include one or more resistors, which may be specifically set according to actual conditions.

[0054] Exemplary, reference Figure 3As shown, the first switch unit 11 includes a relay S1, the second switch unit 12 includes a relay S2, the third switch unit 13 includes a relay S3, the fourth switch unit 14 includes a relay S4, the fifth switch unit 15 includes a relay S5, the first resistor unit 21 includes a resistor R1, the second resistor unit 22 includes a resistor R2, the third resistor unit 23 includes a resistor R3, and the fourth resistor unit 24 includes a resistor R4. Among them, the relay S2 and the resistor R1 are connected in series between the positive DC bus BUS+ and the ground, and the relay S3 and the resistor R2 are connected between the negative DC bus BUS- and the ground. The relay S4 and the resistor R3 are connected in series between the positive DC bus BUS+ and the ground, and the relay S5 and the resistor R4 are connected between the negative DC bus BUS- and the ground.

[0055] In this embodiment, the control unit 41 is connected to the control end of the five switch units. When it receives the first detection instruction, it will first disconnect the fifth switch unit 15, and then adjust the states of the first switch unit 11 to the fourth switch unit 14, so as to measure the voltage values ​​of the positive DC bus BUS+ and the negative DC bus BUS- relative to the ground respectively. Through these voltage data, the control unit 41 calculates the ratio between the first insulation resistance and the second insulation resistance. When the ratio exceeds the insulation threshold preset by the system, the control unit 41 generates an insulation alarm signal to warn of possible insulation defects. By calculating the ratio between the first insulation resistance and the second insulation resistance, it is possible to detect whether the insulation resistance meets the requirements without calculating the specific resistance values ​​of the first insulation resistance and the second insulation resistance respectively. In this way, it is possible to quickly detect whether the insulation resistance meets the requirements, greatly simplify the calculation steps, and improve the calculation accuracy.

[0056] In one embodiment, the insulation detection function is extremely important. The control unit 41 is set to perform insulation detection tasks regularly. The specific operation includes: after receiving a regular detection instruction (for example, a first detection instruction), the control unit 41 automatically disconnects the fifth switch unit 15 to ensure the measurement environment of other switches. Then the states of the first to fourth switch units 14 are gradually adjusted to collect the voltage data of the positive and negative DC bus relative to the ground. These values ​​are input into the internal algorithm module to calculate the ratio of insulation resistance. Once it is detected that the ratio exceeds the safety threshold set by the system, an alarm signal will be immediately displayed on the system interface, and a notification will be sent to the maintenance team through the networked remote monitoring system. In this way, maintenance engineers can quickly take preventive measures to ensure that the insulation performance of the energy storage system is within a safe range and prevent potential risks.

[0057] In one embodiment, the first insulation resistance is the insulation resistance between the positive DC bus BUS+ and the ground, and the second insulation resistance is the insulation resistance between the negative DC bus BUS- and the ground. For example, the resistor Rp represents the first insulation resistance between the positive DC bus BUS+ and the ground, and the resistor Rn represents the second insulation resistance between the negative DC bus BUS- and the ground.

[0058] In this embodiment, the insulation resistance detection circuit of the energy storage power supply circuit realizes accurate insulation monitoring. The control unit 41 can quickly adjust the switch state after receiving the detection instruction, accurately obtain the DC bus voltage, calculate the ratio of insulation resistance, and effectively evaluate the insulation condition. The beneficial effect of this solution lies in the simplicity of its operation. The automated detection process reduces manual intervention, and the calculation accuracy is extremely high. Through precise data processing, insulation faults can be identified in time. At the same time, the system immediately sends an alarm signal when an abnormal situation is detected, which significantly improves the safety and reliability of the energy storage system and ensures the stable operation of the equipment.

[0059] In one embodiment, obtaining the voltage values ​​of the positive DC bus BUS+ relative to the ground and the negative DC bus BUS- relative to the ground in different working states includes: when receiving the first detection instruction, the control unit 41 controls the fifth switch unit 15 to be disconnected, and controls the first switch unit 11, the second switch unit 12, and the third switch unit 13 to be closed; obtaining the first voltage value of the positive DC bus BUS+ relative to the ground, and obtaining the second voltage value of the negative DC bus BUS- relative to the ground. The control unit 41 controls the fourth switch unit 14 to be closed, and obtains the third voltage value of the positive DC bus BUS+ relative to the ground, and obtains the fourth voltage value of the negative DC bus BUS- relative to the ground.

[0060] In this embodiment, in order to measure the voltage values ​​of the positive DC bus BUS+ and the negative DC bus BUS- relative to the ground terminal under different working conditions, the control unit 41 disconnects the fifth switch unit 15 and closes the first, second and third switch units 13 when receiving the first detection instruction. At this time, the system measures the first voltage value P0 and the second voltage value N0 of the positive DC bus BUS+ and the negative DC bus BUS-. Subsequently, the control unit 41 closes the fourth switch unit 14 and measures the third voltage value P1 and the fourth voltage value N1 to obtain voltage data more comprehensively. The control unit 41 is also used to calculate the first ratio Rp1 / Rn1 of the first insulation resistance and the second insulation resistance based on the first voltage value P0, the second voltage value N0, the third voltage value P1 and the fourth voltage value N1, and generate an insulation alarm signal when the first ratio Rp1 / Rn1 exceeds the preset insulation value.

[0061] Specifically, when the first detection instruction is received, the relays S1, S2, and S3 are first closed to obtain the voltage values ​​P0 and N0 of the positive and negative busbars to the ground, that is, P0 represents the voltage value of the positive busbar to the ground, and N0 represents the voltage value of the negative busbar to the ground. At this time, the relationship between the first voltage value P0 and the second voltage value N0 and the resistance in the circuit can be expressed as:

[0062] P0=Rp||Rv,N0=Rn||Rv (1)

[0063] Further, after obtaining the first voltage value P0 and the second voltage value N0, the control unit 41 closes the relay S4 to obtain the third voltage value P1 and the fourth voltage value N1, wherein the relationship between the third voltage value P1 and the fourth voltage value N1 and the resistance in the circuit can be expressed as:

[0064] P1=Rp||Rv||Rb, N1=Rn||Rv (2)

[0065] Wherein, Rv=R1+R2, Rb=R3+R4;

[0066] Furthermore, by solving equations (1) and (2) together, we can obtain: The first ratio of the first insulation resistance to the second insulation resistance can be obtained, and when the first ratio exceeds the preset insulation value, an insulation alarm signal is generated.

[0067] In one embodiment, after calculating Afterwards, you can Filtering can make More accurate.

[0068] Specifically, Rp1 / Rn1 can be used as input data into the following formula:

[0069]

[0070] Wherein, a0, a1, a2, and b0 are filter coefficients, which can be calibrated through simulation and experiment, that is, they can be set by preset values; Y(n) represents output data, X(n) represents input data, and n represents sampling time.

[0071] In one embodiment, the preset insulation value is set to 10%, that is, when the first ratio exceeds 10%, an insulation alarm signal is generated.

[0072] In one embodiment, it is critical to ensure the integrity and safety of the insulation. When the system starts the insulation detection procedure, the control unit 41 will first disconnect the fifth switch unit 15 after receiving the instruction to reduce interference factors, and then close the first to third switch units to measure the preliminary bus voltage value (first and second voltage values). These data provide preliminary information about the current state and the voltage between the bus and the ground. Next, the control unit 41 obtains additional voltage information (third and fourth voltage values) by closing the fourth switch unit, so that the insulation state of the system can be more accurately evaluated. If the voltage ratio is detected to exceed the preset safety threshold, the system will immediately issue an alarm to ensure that the maintenance team can respond quickly and solve possible insulation problems to ensure the safe operation of the entire energy storage system.

[0073] In one embodiment, the control unit 41 is also used to control the first switch unit 11, the fourth switch unit 14, and the fifth switch unit 15 to be disconnected, and the second switch unit 12 and the third switch unit 13 to be closed when receiving the second detection instruction; obtain the fifth voltage value Vp2 of the positive DC bus BUS+ relative to the ground terminal, and obtain the sixth voltage value Vn2 of the negative DC bus BUS- relative to the ground terminal; the control unit 41 is also used to calculate the second voltage ratio of the first insulation resistance to the second insulation resistance based on the fifth voltage value and the sixth voltage value.

[0074] In this embodiment, after closing relays S2 and S3, the fifth voltage value Sixth voltage value

[0075] In one embodiment, ensuring the monitoring of the insulation status is essential for safe operation. The control unit 41 will periodically start the insulation detection program. When the detection instruction is issued, the control unit 41 first disconnects the first switch unit 11, the fourth switch unit 14, and the fifth switch unit 15 to eliminate unnecessary circuit interference, and then closes the second switch unit 12 and the third switch unit 13 in sequence to measure and record the third and fourth voltage values ​​of the positive and negative DC bus BUS-, which provides a more comprehensive analysis of the insulation status of the entire system. If the generated voltage ratio exceeds the safety threshold, the system will immediately issue an alarm signal to prompt the maintenance personnel to respond and check quickly, thereby ensuring the safe operation of the energy storage system.

[0076] In one embodiment, the control unit 41 is further used to control the first switch unit 11, the second switch unit 12, and the third switch unit 13 to be disconnected and the fourth switch unit 14 and the fifth switch unit 15 to be closed after receiving the second detection instruction and after the first delay time. Obtain the seventh voltage value of the positive DC bus BUS+ relative to the ground terminal and obtain the eighth voltage value of the negative DC bus BUS- relative to the ground terminal. The control unit 41 is also used to calculate the third ratio of the first insulation resistance to the second insulation resistance according to the seventh voltage value Vp3 and the eighth voltage value Vn3.

[0077] In this embodiment, after closing relays S4 and S5, the seventh voltage value Eighth voltage value but

[0078] In one embodiment, the first delay time can be set to 10S.

[0079] In one embodiment, the control unit 41 is further configured to generate an insulation alarm signal when the second ratio and / or the third ratio exceeds a preset insulation value.

[0080] It is understandable that when any of the second ratio and the third ratio exceeds the preset insulation value, an insulation alarm signal will be generated. When it is greater than 10%, an insulation alarm signal will be issued. When it is greater than 10%, an insulation alarm signal will be issued. and When both are greater than 10%, an insulation alarm signal will also be issued. The system will immediately issue an alarm to ensure immediate prompts and ensure the safety of the equipment. This multi-dimensional monitoring improves the accuracy and efficiency of fault identification, and the maintenance team can respond quickly to avoid potential risks. In addition, the mechanism is easy to integrate into existing energy storage systems, significantly improving the overall safety and reliability of the system without significantly changing the architecture.

[0081] In one embodiment, the first detection instruction and the second detection instruction are both detection instructions for detecting whether the insulation resistance meets the requirements, but the frequencies of the first detection instruction and the second detection instruction are different, wherein the detection frequency of the first detection instruction is less than the detection frequency of the second detection instruction, but the accuracy of the detection performed according to the first detection instruction is greater than the accuracy of the detection performed according to the second detection instruction. By setting two different detection methods, it is possible to more comprehensively detect whether the insulation resistance meets the requirements, thereby improving the accuracy of the detection.

[0082] In one embodiment, reference Figure 2 As shown, the insulation resistance detection circuit further includes: a first voltage source Us, a fifth resistance unit 25 and a sixth switch unit 16.

[0083] Specifically, the first voltage source Us, the fifth resistor unit 25 and the sixth switch unit 16 are connected in series in sequence and then connected in parallel with the first switch unit 11; the control unit 41 is also used to control the first switch unit 11, the fourth switch unit 14, and the fifth switch unit 15 to be disconnected, and the second switch unit 12, the third switch unit 13, and the sixth switch unit 16 to be closed after receiving the third detection instruction. Obtain the ninth voltage value Vp4 of the positive DC bus BUS+ relative to the ground terminal, and obtain the tenth voltage value Vn4 of the negative DC bus BUS- relative to the ground terminal; the control unit 41 is also used to calculate the fourth ratio of the first insulation resistance to the second insulation resistance based on the ninth voltage value and the tenth voltage value And in the fourth ratio When the preset insulation value is exceeded, an insulation alarm signal is generated.

[0084] In one embodiment, the insulation resistance detection circuit further includes: a first voltage source Us, a fifth resistance unit 25 (including a resistor R5 ) and a sixth switch unit 16 .

[0085] Specifically, the first voltage source Us, the fifth resistor unit 25 and the sixth switch unit 16 are sequentially connected in series and then connected in parallel with the first switch unit 11; the control unit is also used to control the first switch unit 11, the second switch unit 12, the fourth switch unit, and the fifth switch unit to be disconnected, control the third switch unit and the sixth switch unit 16 to be closed, and control the first voltage source Us to be the first level after receiving the third detection instruction; obtain the ninth voltage value across the second resistor unit; control the first voltage source Us to be the second level; and obtain the tenth voltage value across the second resistor unit;

[0086] Further, after the second delay time, the first switch unit 11, the third switch unit, the fourth switch unit, and the fifth switch unit are all controlled to be disconnected, the second switch unit 12 and the sixth switch unit 16 are all controlled to be closed, and the first voltage source Us is controlled to be the first level; the eleventh voltage value across the first resistor is obtained; the first voltage source Us is controlled to be the second level; and the twelfth voltage value across the first resistor is obtained;

[0087] Then, the control unit is further used to calculate a fourth ratio of the first insulation resistance to the second insulation resistance according to the ninth voltage value, the tenth voltage value, the eleventh voltage value, and the twelfth voltage value. And in the fourth ratio When the preset insulation value is exceeded, an insulation alarm signal is generated.

[0088] In this embodiment, the third detection instruction may be a power-on instruction when the system is turned on. For example, after the system is powered on, the insulation resistance detection circuit first detects whether the insulation resistance meets the requirements. Specifically, the control unit 41 controls the first switch unit 11, the second switch unit 12, the fourth switch unit 14, and the fifth switch unit 15 to be disconnected, controls the third switch unit 13 and the sixth switch unit 16 to be closed, and controls the first voltage source Us to be the first level (low level), and obtains the ninth voltage value across the second resistance unit 22 (including the resistance R2). U1 When the first voltage source Us is controlled to be at the second level (high level), the tenth voltage value across the second resistance unit is obtained. U1' .

[0089] Then the ninth voltage value U1 , Tenth voltage value U1 ' The relationship between the resistor R5, the resistor R2, the insulation resistor Rn, and the first voltage source Us can be expressed as:

[0090] In this embodiment, after the second delay time (for example, 20S), the first switch unit 11, the third switch unit 13, the fourth switch unit 14, and the fifth switch unit 15 are all disconnected, the second switch unit 12 and the sixth switch unit 16 are all closed, and the first voltage source Us is controlled to be at the first level (low level), and the eleventh voltage value across the first resistor is obtained. U2 When the first voltage source Us is controlled to be at the second level (high level), the twelfth voltage value across the first resistor is obtained. U2 ' .

[0091] Then the eleventh voltage value U2 , 12th voltage value U1' The relationship between the resistor R5, the resistor R1, the insulation resistor Rp, and the first voltage source Us can be expressed as:

[0092] Then, the control unit is also used to calculate a fourth ratio of the first insulation resistance Rp and the second insulation resistance Rn according to the ninth voltage value, the tenth voltage value, the tenth voltage value, and the eleventh voltage value, and generate an insulation alarm signal when the fourth ratio exceeds the preset insulation value.

[0093] Specifically: the first insulation resistance Rp can be expressed as:

[0094]

[0095] The first insulation resistance Rn can be expressed as:

[0096]

[0097] Among them, U1 is the voltage on R2 when Us is at a low level, and U1′ is the voltage on R2 when Us is at a high level; U2 is the voltage on R1 when Us is at a low level, and U2′ is the voltage on R1 when Us is at a high level; Us represents the voltage when the first voltage source is at a high level.

[0098] Then calculate the fourth ratio of the first insulation resistance to the second insulation resistance

[0099] In one embodiment, the control unit 41 is further configured to disconnect the DC conversion circuit 100 and the AC conversion circuit 200 when an insulation alarm signal is generated.

[0100] In this embodiment, the control unit 41 is also used to disconnect the DC conversion circuit 100 and the AC conversion circuit 200 when an insulation alarm signal is generated, thereby avoiding safety problems caused by insulation resistance not meeting requirements, and improving the reliability of the energy storage power supply circuit.

[0101] Exemplarily, after receiving the power-on command, the control unit 41 detects whether the DC conversion circuit 100 and the AC conversion circuit 200 are connected; when the control unit 41 detects that the DC conversion circuit 100 and the AC conversion circuit 200 are connected, it calculates whether the first insulation resistance and the second insulation resistance meet the requirements, and when the resistance value of the first insulation resistance or the second insulation resistance does not meet the requirements, it disconnects the DC conversion circuit 100 and the AC conversion circuit 200, thereby ensuring the power safety of the energy storage power supply circuit.

[0102] In one embodiment, the sum of the resistance values ​​of the third resistance unit 23 and the fourth resistance unit 24 is greater than the sum of the resistance values ​​of the first resistance unit 21 and the second resistance unit 22 .

[0103] In this embodiment, the design specifically configures the resistance unit so that the total resistance of the third resistance unit 23 and the fourth resistance unit 24 is greater than the total resistance of the first resistance unit 21 and the second resistance unit 22. This configuration optimizes the potential distribution in the circuit, ensures accurate regulation of voltage and current during operation and detection, and improves the safety and measurement accuracy of the system.

[0104] For example, in the insulation detection of the energy storage system, the configuration of the resistor plays a key role. In order to improve the accuracy of the resistance detection, the system sets the total resistance of the third resistor unit 23 and the fourth resistor unit 24 to be greater than the total resistance of the first and second resistor units. This design adjusts the potential difference on different resistors so that the system can more sensitively reflect the insulation state of the DC bus when performing insulation detection. When the detection program is started, the control unit 41 adjusts the state of the relevant switches in sequence and measures the bus-to-ground voltage according to the configuration of the resistor network. This method not only increases the accuracy of the data, but also improves the response speed to abnormal conditions. Once an abnormal situation is detected, the system will immediately issue an alarm, prompting the maintenance team to handle the fault in a timely manner to ensure the safe and efficient operation of the energy storage system.

[0105] In one embodiment, reference Figure 3 As shown, the energy storage power supply circuit also includes an intelligent gateway circuit, and the intelligent gateway circuit includes a gateway K1, and the gateway K1 is arranged on the DC bus.

[0106] In one embodiment, reference Figure 3 As shown, the insulation detection circuit is represented by 10.

[0107] The present application also provides an energy storage power supply circuit, referring to Figure 4 As shown, the energy storage power supply circuit includes: a DC conversion circuit 100, an AC conversion circuit 200, an intelligent gateway circuit 500 and an insulation resistance detection circuit as any one of the above items.

[0108] Specifically, the input end of the DC conversion circuit 100 is used to connect to the DC power supply 300, and the output end of the DC conversion circuit 100 is connected to the DC bus. The input end of the AC conversion circuit 200 is used to connect to the photovoltaic module 400, and the output end of the AC conversion circuit 200 is connected to the DC bus. The intelligent gateway circuit 500 is arranged on the DC bus. Specifically, the input end of the DC conversion circuit 100 is connected to the DC power supply 300, and the output end is connected to the DC bus; the input end of the AC conversion circuit 200 is connected to the photovoltaic module 400, and the output end is also connected to the DC bus. In addition, the intelligent gateway circuit 500 is installed on the DC bus to optimize the flow of power and system monitoring.

[0109] In one embodiment, a complete energy storage power supply system includes DC conversion, AC conversion and intelligent gateway configuration to achieve efficient energy management. In this system, the insulation resistance detection circuit plays a key role. The DC and AC conversion circuits 200 receive electrical energy from the power supply and the photovoltaic module 400 respectively, and send it to the DC bus after conversion. Through the intelligent gateway circuit 500 installed on the DC bus, the entire system realizes intelligent control of energy flow and real-time data monitoring. During the detection operation, the insulation resistance detection circuit can quickly identify any possible insulation problems. By collecting voltage data at multiple points on the DC bus, it evaluates the insulation status of the bus, and once the detection indication exceeds the safety threshold, the system immediately triggers an alarm. The maintenance team can therefore immediately mobilize resources for inspection and repair to ensure that the reliability and safety of the energy storage system are continuously guaranteed.

[0110] An embodiment of the present application also provides an energy storage device, including the energy storage power supply circuit as described above.

[0111] In this embodiment, the energy storage device includes the energy storage power supply circuit as described above. The power supply circuit integrates the DC conversion circuit 100, the AC conversion circuit 200, the intelligent gateway circuit 500 and the insulation resistance detection circuit, can efficiently perform power conversion, and provide a comprehensive insulation monitoring function to ensure the reliability and safety of the equipment.

[0112] In one embodiment, the energy storage device uses an integrated energy storage power supply circuit with complete conversion capabilities from input power to output. The DC conversion circuit 100 and the AC conversion circuit 200 process the power from the DC power supply and the photovoltaic module 400 respectively, and transmit them to the DC bus after optimization. The intelligent gateway circuit 500 arranged on the DC bus is responsible for real-time monitoring of power flow and system status. In addition, the insulation resistance detection circuit in the device continuously monitors the insulation condition. It evaluates the insulation state of the circuit by accurately measuring the voltage behavior on the DC bus. When it is detected that the insulation resistance ratio exceeds the safety threshold, the system will automatically trigger an alarm, prompting the maintenance team to check and intervene. This mechanism not only protects the integrity of the energy storage device, but also ensures the safety and stability of the overall operation.

[0113] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0114] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0115] In the embodiments provided in the present application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0116] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

[0117] Each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0118] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Claims

1. An insulation resistance detection circuit for an energy storage power supply circuit, characterized in that: The energy storage power supply circuit includes: a DC conversion circuit and an AC conversion circuit, wherein the input end of the DC conversion circuit is used to be connected to a DC power supply, and the output end of the DC conversion circuit is connected to a DC bus; the input end of the AC conversion circuit is used to be connected to a photovoltaic module, and the output end of the AC conversion circuit is connected to the DC bus; The insulation resistance detection circuit comprises: a first switch unit, a second switch unit, a third switch unit, a fourth switch unit, a fifth switch unit, a first resistor unit, a second resistor unit, a third resistor unit, a fourth resistor unit and a control unit; the first resistor unit and the second switch unit are connected in series, connected between the first end of the first switch unit and the positive DC bus, and the second end of the first switch unit is grounded; the second resistor unit and the third switch unit are connected in series, connected between the negative DC bus and the first end of the first switch unit; the third resistor unit and the fourth switch unit are connected in series, connected between the first end of the first switch unit and the positive DC bus; the fourth resistor unit and the fifth switch unit are connected in series, connected between the negative DC bus and the first end of the first switch unit; The control unit is connected to the first switch unit, the second switch unit, the third switch unit, the fourth switch unit and the fifth switch unit; the control unit is used to control the fifth switch unit to be disconnected when receiving the first detection instruction, and control the working states of the first switch unit, the second switch unit, the third switch unit and the fourth switch unit, and obtain the voltage values ​​of the positive DC bus relative to the ground terminal and the negative DC bus relative to the ground terminal under different working states; The control unit is also used to calculate a first ratio of the first insulation resistance to the second insulation resistance based on the voltage values ​​of the positive DC bus relative to the ground terminal and the negative DC bus relative to the ground terminal under different working conditions, and generate an insulation alarm signal when the first ratio exceeds a preset insulation value.

2. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 1, characterized in that: The obtaining of voltage values ​​of the positive DC bus relative to the ground and the negative DC bus relative to the ground in different working states includes: When receiving the first detection instruction, the control unit controls the fifth switch unit to be disconnected, and controls the first switch unit, the second switch unit, and the third switch unit to be closed; obtains a first voltage value of the positive DC bus relative to the ground terminal, and obtains a second voltage value of the negative DC bus relative to the ground terminal; The control unit controls the fourth switch unit to close, obtains a third voltage value of the positive DC bus relative to the ground, and obtains a fourth voltage value of the negative DC bus relative to the ground.

3. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 1, characterized in that: The control unit is further configured to control the first switch unit, the fourth switch unit, and the fifth switch unit to be disconnected, and control the second switch unit and the third switch unit to be closed when receiving a second detection instruction; Acquire a fifth voltage value of the positive DC bus relative to the ground terminal, and acquire a sixth voltage value of the negative DC bus relative to the ground terminal; The control unit is further configured to calculate a second voltage ratio between the first insulation resistance and the second insulation resistance according to the fifth voltage value and the sixth voltage value.

4. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 3, characterized in that: The control unit is further configured to, upon receiving a second detection instruction, control the first switch unit, the second switch unit, and the third switch unit to be disconnected, and control the fourth switch unit and the fifth switch unit to be closed after a first delay time has elapsed; Acquire a seventh voltage value of the positive DC bus relative to the ground terminal, and acquire an eighth voltage value of the negative DC bus relative to the ground terminal; The control unit is further configured to calculate a third ratio of the first insulation resistance to the second insulation resistance according to the seventh voltage value and the eighth voltage value.

5. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 4, characterized in that: The control unit is further configured to generate the insulation alarm signal when the second ratio and / or the third ratio exceeds the preset insulation value.

6. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 1, characterized in that: The insulation resistance detection circuit further includes: a first voltage source, a fifth resistance unit and a sixth switch unit; The first voltage source, the fifth resistor unit and the sixth switch unit are sequentially connected in series and then connected in parallel with the first switch unit; The control unit is further used to, after receiving the third detection instruction, control the first switch unit, the second switch unit, the fourth switch unit, and the fifth switch unit to be disconnected, control the third switch unit and the sixth switch unit to be closed, control the first voltage source to be at the first level; obtain the ninth voltage value across the second resistor unit; control the first voltage source to be at the second level; and obtain the tenth voltage value across the second resistor unit; After the second delay time, the first switch unit, the third switch unit, the fourth switch unit, and the fifth switch unit are all controlled to be disconnected, the second switch unit and the sixth switch unit are all controlled to be closed, and the first voltage source is controlled to be at the first level; an eleventh voltage value across the first resistor is obtained; the first voltage source is controlled to be at the second level; and a twelfth voltage value across the first resistor is obtained; The control unit is also used to calculate a fourth ratio of the first insulation resistance to the second insulation resistance based on the ninth voltage value, the tenth voltage value, the eleventh voltage value, and the twelfth voltage value, and generate the insulation alarm signal when the fourth ratio exceeds the preset insulation value.

7. The insulation resistance detection circuit of the energy storage power supply circuit according to claim 1, characterized in that: The control unit is further configured to disconnect the DC conversion circuit and the AC conversion circuit when the insulation alarm signal is generated.

8. The insulation resistance detection circuit of the energy storage power supply circuit according to any one of claims 1 to 7, characterized in that: The sum of the resistance values ​​of the third resistance unit and the fourth resistance unit is greater than the sum of the resistance values ​​of the first resistance unit and the second resistance unit.

9. An energy storage power supply circuit, characterized in that: The energy storage power supply circuit includes: A DC conversion circuit, wherein the input end of the DC conversion circuit is used to be connected to a DC power supply, and the output end of the DC conversion circuit is connected to a DC bus; An AC conversion circuit, wherein the input end of the AC conversion circuit is used to be connected to a photovoltaic module, and the output end of the AC conversion circuit is connected to the DC bus; An intelligent gateway circuit is arranged on the DC bus; An insulation resistance detection circuit as claimed in any one of claims 1 to 8.

10. An energy storage device, characterized in that: The invention comprises the energy storage power supply circuit as claimed in claim 9.

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