Photovoltaic insulation impedance detection circuit and energy storage system

Abstract

The invention relates to the technical field of energy storage power supplies, and mainly provides a photovoltaic insulation resistance detection circuit and an energy storage system, the circuit comprises a detection module, a first control module, at least one second control module and at least one time delay module; the first control module and each second control module are respectively connected with the detection module and the corresponding photovoltaic input source, and each second control module is connected with the corresponding time delay module. When the first control module is connected with the photovoltaic input source, the corresponding photovoltaic input source is connected with the detection module; the delay modules are used for delaying the photovoltaic input voltage, and the delay times of the plurality of delay modules are different, so that detection time sequences which are not overlapped with each other are automatically formed; and the second control module controls the corresponding photovoltaic input source to be connected to the detection module when receiving the delayed input voltage, so that each path of photovoltaic input source is sequentially detected, on the basis, multi-path detection can be completed through one detection module, complex control logic is not needed, the circuit cost is reduced, and the practicability of the energy storage system is improved.

Description

Technical Field

[0001] This invention relates to the technical field of energy storage power supplies, and more particularly to a photovoltaic insulation impedance detection circuit and energy storage system. Background Technology

[0002] During the operation of energy storage power supplies, certification requirements, operational safety, and system stability are key considerations. Insulation resistance testing of the PV input terminal to ground (PE) is a crucial step in ensuring these requirements are met. When the tested insulation resistance is less than the specified value, the power supply must promptly report an insulation fault to prevent safety issues. In existing insulation resistance detection circuits, insulation resistance is often calculated by acquiring voltage values ​​using an MCU. To improve detection accuracy and avoid false alarms, a single-channel detection method is required. However, for photovoltaic energy storage power supplies with multiple PV inputs, this single-channel detection method requires multiple signals to control the detection sequence of each PV input to achieve individual detection control for each PV input. In actual product design, MCU I / O resources are often limited. Adding multiple control signals necessitates increasing the number of MCU pins, which directly leads to a significant increase in product cost. Furthermore, increasing the number of MCU pins complicates MCU resource configuration and increases the design difficulty of software control logic, causing numerous inconveniences for product development and production. Summary of the Invention

[0003] The present invention provides a photovoltaic insulation impedance detection circuit and energy storage system, which aims to solve the technical problems of high cost and complex detection of insulation of photovoltaic input sources in the prior art.

[0004] To solve the above-mentioned technical problems, one technical solution adopted in the embodiments of the present invention is: to provide a photovoltaic insulation impedance detection circuit, the photovoltaic insulation impedance detection circuit including a detection module, a first control module, at least one second control module and at least one delay module; The first control module and each of the second control modules are respectively connected to the detection module and the corresponding photovoltaic input source. Each of the second control modules is also connected to a corresponding delay module. The first control module and each of the delay modules are also respectively connected to a photovoltaic input source. The first control module is used to output a first control signal for a first preset time when the photovoltaic input source is connected, and to control the connected photovoltaic input source to connect to the detection module during the duration of the first control signal, so that the detection module can detect the insulation impedance of the connected photovoltaic input source; Each of the delay modules is used to receive the input voltage of the connected photovoltaic input source and input the input voltage to the corresponding second control module after delaying the input voltage by a target time. When there are at least two delay modules, the target time of each delay module is different. Each of the second control modules is configured to output a second control signal for a second preset time when receiving the input voltage, and control the connected photovoltaic input source to connect to the detection module during the duration of the second control signal, so that the detection module can detect the insulation impedance of the connected photovoltaic input source.

[0005] Optionally, the first control module includes a first signal generation unit and a first switching unit; The first signal generation unit is connected to the first switching unit and the corresponding photovoltaic input source, and the first switching unit is connected to the detection module and the corresponding photovoltaic input source. The first signal generation unit is configured to receive and store the input voltage of the photovoltaic input source when the photovoltaic input source is connected, and output a first control signal based on the stored voltage; and The first control signal is stopped being output when the stored voltage is greater than the first preset value; The first switching unit is configured to, upon receiving the first control signal, turn on based on the first control signal to connect the connected photovoltaic input source to the detection module; and The system shuts down when the first control signal is not received, thereby disconnecting the photovoltaic input source from the detection module.

[0006] Optionally, the first switching unit includes a switching transistor Q3, a switching transistor Q7, a resistor R20, and a resistor R23; The control terminal of the switch Q7 is connected to the first signal generation unit. The first terminal of the switch Q7 is connected to the control terminal of the switch Q3 through the resistor R23. The second terminal of the switch Q7 is grounded. The first terminal of the switch Q3 is connected to the corresponding photovoltaic input source. The first terminal of the switch Q3 is also connected to the control terminal of the switch Q3 through the resistor R20. The second terminal of the switch Q3 is connected to the detection module.

[0007] Optionally, the first signal generation unit includes a switch Q5, a resistor R24, a diode D5, a capacitor C8, a capacitor C10, and a capacitor C11; The first terminal of the switch Q5 is connected to the corresponding photovoltaic input source. The first terminal of the switch Q5 is also connected to the control terminal of the switch Q5 through the resistor R24. The control terminal of the switch Q5 is also grounded through the capacitor C11. The control terminal of the switch Q5 is also connected to the anode of the diode D5. The cathode of the diode D5 is also grounded through the capacitor C10. The capacitor C10 is also connected to the corresponding photovoltaic input source. The second terminal of the switch Q5 is grounded through the capacitor C8. The second terminal of the switch Q5 is also connected to the first switching unit.

[0008] Optionally, the first control module further includes a first discharge unit; The first discharge unit is connected to the cathode of the diode D5; The first discharge unit is used to discharge the energy stored in the capacitors C10 and C11 when the corresponding connected photovoltaic input source is disconnected.

[0009] Optionally, the first signal generation unit further includes a Zener diode DZ1; The cathode of the Zener diode DZ1 is connected to the corresponding photovoltaic input source, and the anode of the Zener diode DZ1 is connected to the first end of the switching transistor Q5.

[0010] Optionally, the delay module includes a capacitor C7, a resistor R22, and a Zener diode DZ3; The resistor R22 is connected to the capacitor C7 and the corresponding photovoltaic input source respectively. The capacitor C7 is also connected to the cathode of the Zener diode DZ3. The capacitor C7 is also used for grounding. The anode of the Zener diode DZ3 is connected to the second control module.

[0011] Optionally, the photovoltaic insulation impedance detection circuit further includes at least two fault location modules; The at least two fault location modules are respectively connected to the first control module and at least one second control module, the at least two fault location modules are also connected to the detection module, and the at least two fault location modules are also used to receive fault signals; The fault location module is used to output an indication signal when it receives a first control signal output by the corresponding first control module or a second control signal output by the second control module and the fault signal, so as to indicate that the connected photovoltaic input source is faulty.

[0012] Optionally, the detection module includes relays RLY1 and RLY2, operational amplifier U1, resistors R1, R3, R7, R10, R12, R15, R17, and switching transistors Q1 and Q2. The coil terminal of relay RLY1 is connected to the power supply and the first terminal of switching transistor Q1, respectively. The connection terminal of relay RLY1 is connected to resistors R3 and R7, respectively. The control terminal of switching transistor Q1 is connected to the controller. The second terminal of switching transistor Q1 is grounded. Resistor R3 is also connected to the first control module or at least one second control module through resistor R1. Resistor R3 is also connected to resistor R10. Resistor R10 is also connected to resistor R17 and the connection terminal of relay RLY2 through resistor R15, respectively. The connection terminal of relay RLY2 and resistor R17 are both grounded. The coil terminal of relay RLY2 is connected to the power supply and the first terminal of switching transistor Q2, respectively. The control terminal of switching transistor Q2 is connected to the controller. The second terminal of switching transistor Q2 is also grounded. The first input terminal of operational amplifier U1 is connected to resistor R7. The second input terminal of operational amplifier U1 is also grounded through resistor R12. The output terminal of operational amplifier U1 is connected to the controller.

[0013] To solve the above-mentioned technical problems, another technical solution adopted in the embodiments of the present invention is to provide an energy storage system, the energy storage system comprising: Multiple photovoltaic input sources; and The photovoltaic insulation impedance detection circuit described above is connected to multiple photovoltaic input sources respectively.

[0014] Unlike related technologies, the present invention provides a photovoltaic insulation impedance detection circuit and energy storage system. The circuit includes a detection module, a first control module, at least one second control module, and at least one delay module. The first control module and each of the second control modules are respectively connected to the detection module and a corresponding photovoltaic input source. Each of the second control modules is also connected to a corresponding delay module. The first control module and each of the delay modules are also respectively connected to a photovoltaic input source. The first control module outputs a first control signal for a first preset time when the photovoltaic input source is connected, and controls the connected photovoltaic input source to connect to the detection module within the duration of the first control signal, so that the detection module can accurately and stably complete the detection of the insulation impedance of the photovoltaic input source within the preset time. Each delay module receives the input voltage of the connected photovoltaic input source and inputs the input voltage to the corresponding second control module after delaying the input voltage by a target time. When there are at least two delay modules, the target time of each delay module is different, thereby automatically forming a non-overlapping detection sequence, avoiding mutual interference between signals, and achieving orderly switching without additional complex control logic. Each second control module outputs a second control signal for a second preset time when the input voltage is received, and controls the connected photovoltaic input source to connect to the detection module within the duration of the second control signal, so that the detection module can sequentially and time-divisionally complete the detection of the insulation impedance of each photovoltaic input source. Multi-channel detection is achieved using only one set of detection modules, effectively simplifying the circuit structure, reducing hardware costs, and improving the system's versatility and practicality. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0016] Figure 1 This is a structural block diagram of an energy storage system provided in an embodiment of the present invention; Figure 2 This is a structural block diagram of a photovoltaic insulation impedance detection circuit provided in an embodiment of the present invention; Figure 3 This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in an embodiment of the present invention; Figure 4 This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention; Figure 5 This is a circuit diagram of a detection module provided in an embodiment of the present invention; Figure 6This is a structural block diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention; Figures 7a-7c This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] It should be noted that, unless otherwise specified, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present invention. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different module division or in a different order than that shown in the device schematic diagram or the flowchart.

[0019] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0020] Please see Figure 1 , Figure 1 This is a structural block diagram of an energy storage system provided in an embodiment of the present invention, such as... Figure 1 As shown, the energy storage system 100 includes multiple photovoltaic input sources 10 and a photovoltaic insulation impedance detection circuit 20, and all of the multiple photovoltaic input sources 10 are connected to the photovoltaic insulation impedance detection circuit 20.

[0021] Specifically, the photovoltaic insulation impedance detection circuit 20 receives the input voltage of the photovoltaic input source 10 and starts working based on the received input voltage to detect the insulation impedance of the corresponding connected photovoltaic input source 10, thereby determining whether the corresponding photovoltaic input source 10 is operating safely based on the insulation impedance. Therefore, when the photovoltaic insulation impedance detection circuit 20 is connected to multiple photovoltaic input sources 10, it can sequentially perform insulation tests on multiple photovoltaic input sources 10, thereby determining whether the current photovoltaic input source 10 is operating safely based on the test results, thus improving the safety of the energy storage system 100 while reducing testing costs.

[0022] In some embodiments, please refer to Figure 2 , Figure 2 This is a structural block diagram of a photovoltaic insulation impedance detection circuit provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the photovoltaic insulation impedance detection circuit 20 includes a detection module 21, a first control module 22, at least one second control module 23, and at least one delay module 24; The first control module 22 and each of the second control modules 23 are respectively connected to the detection module 21 and the corresponding photovoltaic input source 10. Each of the second control modules 23 is also connected to a corresponding delay module 24. The first control module 22 and each of the delay modules 24 are also respectively connected to a photovoltaic input source 10. The first control module 22 is used to output a first control signal for a first preset time when the photovoltaic input source 10 is connected, and to control the connected photovoltaic input source 10 to connect to the detection module 21 during the duration of the first control signal, so that the detection module 21 detects the insulation impedance of the connected photovoltaic input source 10. Each of the delay modules 24 is used to receive the input voltage of the connected photovoltaic input source 10, and input the input voltage to the corresponding second control module 23 after delaying the input voltage by a target time. When there are at least two delay modules 24, the target time of each delay module 24 is different. Each of the second control modules 23 is used to output a second control signal for a second preset time when the input voltage is received, and to control the connected photovoltaic input source 10 to connect to the detection module 21 during the duration of the second control signal, so that the detection module 21 detects the insulation impedance of the connected photovoltaic input source 10.

[0023] It is understood that the sum of the number of the first control module 22 and the second control module 23 is equal to the number of photovoltaic input sources 10. The first control module 22 and at least one second control module 23 are connected to a plurality of photovoltaic input sources 10. The at least one delay module 24 is connected to at least one photovoltaic input source 10 connected to the second control module 23. The number of the second control module 23 and the delay module 24 increases as the number of photovoltaic input sources 10 increases. For example, when the number of photovoltaic input sources 10 is 5, the photovoltaic insulation impedance detection circuit 20 includes a first control module 22, four second control modules 23, and four delay modules 24.

[0024] When multiple photovoltaic input sources 10 are connected to the photovoltaic insulation impedance detection circuit 20, the first control module 22 receives the input voltage of the connected photovoltaic input source 10 and starts working based on the input voltage to output a first control signal for a first preset time. After the first control module 22 outputs the first control signal for the first preset time, the first control module 22 controls the connected photovoltaic input source 10 to connect to the detection module 21 during the duration of the first control signal, so that the detection module 21 performs insulation detection on the photovoltaic input source 10 connected to the first control module 22 during the duration of the first control signal to determine whether the photovoltaic input source 10 connected to the first control module 22 is operating stably.

[0025] If multiple photovoltaic input sources 10 simultaneously output the input voltage, the delay module 24 receives the input voltage of the corresponding photovoltaic input source 10 and outputs it to the corresponding second control module 23 after delaying the input voltage by a target time. This allows the second control module 23 to start operating based on the input voltage after the target time. Upon receiving the input voltage, the second control module 23 outputs a second control signal for a second preset time based on the input voltage. During the duration of the second control signal, it controls the connected photovoltaic input source 10 to connect to the detection module 21. This allows the detection module 21 to perform insulation impedance detection on the connected photovoltaic input source 10 during the duration of the second control signal, thereby determining whether the photovoltaic input source 10 connected to the second control module 23 is operating stably.

[0026] It should be noted that the delay module 24 is mainly used to delay the input voltage of the corresponding photovoltaic input source 10 to the corresponding second control module 23 after a target time when the photovoltaic input source 10 is connected. This allows the second control module 23 to stop working while the preceding photovoltaic input source 10 is being detected, and then start working after the target time to connect the corresponding photovoltaic input source 10 to the detection module 21. Based on this, the delay module 24 can be used to sequentially perform insulation impedance testing on multiple photovoltaic input sources 10, reducing the cost and difficulty of insulation testing while improving the safety and stability of the energy storage system.

[0027] In some embodiments, when there are at least two delay modules 24, the target times extended by the at least two delay modules 24 are different. Specifically, the target times corresponding to the at least two delay modules 24 are sequentially increasing, and the difference between the target times of two adjacent delay modules 24 is the same.

[0028] In yet another embodiment, such as Figure 2 As shown, the first control module 22 includes a first signal generation unit 221 and a first switching unit 222; The first signal generation unit 221 is connected to the first switching unit 222 and the corresponding photovoltaic input source 10, respectively; the first switching unit 222 is connected to the detection module 21 and the corresponding photovoltaic input source 10, respectively. The first signal generation unit 221 is used to receive and store the input voltage of the photovoltaic input source 10 when the photovoltaic input source 10 is connected, and output a first control signal based on the stored voltage; and The first control signal is stopped being output when the stored voltage is greater than the first preset value; The first switching unit 222 is configured to, upon receiving the first control signal, turn on based on the first control signal to connect the connected photovoltaic input source 10 to the detection module 21; and The photovoltaic input source 10 is shut off when the first control signal is not received, thereby disconnecting the photovoltaic input source 10 from the detection module 21.

[0029] Specifically, when the first control module 22 is connected to the corresponding photovoltaic input source 10, the first signal generation unit 221 receives and stores the input voltage of the photovoltaic input source 10, and outputs the first control signal while storing the input voltage. After a first preset time, if the input voltage stored by the first signal generation unit 221 is greater than a first preset value, the first signal generation unit 221 will stop outputting the first control signal. When the first signal generation unit 221 outputs the first control signal, the first switch unit 222 receives the first control signal and turns on based on the first control signal. When the first switch unit 222 turns on, the photovoltaic input source 10 connected to the first control module 22 will be connected to the detection module 21 through the first switch unit 222, so that the detection module 21 receives the current input voltage of the photovoltaic input source 10, detects the insulation resistance of the current photovoltaic input source 10 based on the input voltage, and then determines whether the photovoltaic input source 10 is operating stably based on the insulation resistance.

[0030] In some embodiments, please refer to Figure 3 , Figure 3 This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the first switching unit 222 includes a switching transistor Q3, a switching transistor Q7, a resistor R20, and a resistor R23; the first signal generation unit 221 includes a switching transistor Q5, a resistor R24, a diode D5, a capacitor C8, a capacitor C10, and a capacitor C11. The control terminal of the switch Q7 is connected to the first signal generation unit 221. The first terminal of the switch Q7 is connected to the control terminal of the switch Q3 through the resistor R23. The second terminal of the switch Q7 is used for grounding. The first terminal of the switch Q3 is connected to the corresponding photovoltaic input source 10. The first terminal of the switch Q3 is also connected to the control terminal of the switch Q3 through the resistor R20. The second terminal of the switch Q3 is connected to the detection module 21.

[0031] The first terminal of the switch Q5 is connected to the corresponding photovoltaic input source 10. The first terminal of the switch Q5 is also connected to the control terminal of the switch Q5 through the resistor R24. The control terminal of the switch Q5 is also grounded through the capacitor C11. The control terminal of the switch Q5 is also connected to the anode of the diode D5. The cathode of the diode D5 is also grounded through the capacitor C10. The capacitor C10 is also connected to the corresponding photovoltaic input source 10. The second terminal of the switch Q5 is grounded through the capacitor C8. The second terminal of the switch Q5 is also connected to the first switching unit 222.

[0032] Specifically, when the first control module 22 is connected to the first photovoltaic input source 10, the input voltage of the photovoltaic input source 10 charges the capacitor C11 through the resistor R24. When the capacitor C11 starts charging, the voltage across the resistor R24 ​​is greater than the forward voltage drop of the switch Q5, thus turning on the switch Q5. After the switch Q5 turns on, it transmits the input voltage of the photovoltaic input source 10 to the capacitor C8, causing the capacitor C8 to start charging. When the voltage of the capacitor C8 is greater than a preset threshold, a first control signal is output. During the charging process of the capacitor C11, as the energy stored in C11 increases, the voltage across the resistor R24 ​​decreases. After a first preset time, the voltage across the resistor R24 ​​becomes less than the forward voltage drop of the switch Q5, thus turning off the switch Q5. When the switch Q5 is turned off, it stops transmitting the input voltage. At this time, the capacitor C8 begins to discharge, and stops outputting the first control signal when the voltage of the capacitor C8 is less than a preset threshold. Therefore, the time taken for the voltage of the capacitor C8 to be greater than the preset threshold during the charging and discharging process is the first preset time. The charging time of the capacitor C8 is the on-time of the switch Q5.

[0033] When capacitor C8 outputs a first control signal for a first preset time based on the stored voltage, switch Q7 receives the first control signal and turns on based on the first control signal. When switch Q7 turns on, switch Q3 also turns on, thereby connecting the photovoltaic input source 10 to the detection module 21, and allowing the detection module 21 to detect the insulation resistance of the connected photovoltaic input source 10. After the first preset time, if switch Q7 does not receive the first control signal, switch Q7 turns off, and switch Q3 also turns off, thereby disconnecting the photovoltaic input source 10 from the detection module 21, and causing the detection module 21 to stop detecting the insulation resistance of the corresponding photovoltaic input source 10. It should be noted that the photovoltaic input source 10 charges capacitor C10 on one hand and capacitor C11 on the other hand through resistor R24. Therefore, the charging time of capacitor C10 is faster than that of capacitor C11, diode D5 is in the off state, and eventually the voltages of capacitor C11 and capacitor C10 will be equal.

[0034] In some embodiments, such as Figure 2 As shown, the first control module 22 further includes a first discharge unit 223; The first discharge unit 223 is connected to the cathode of the diode D5; The first discharge unit 223 is used to discharge the energy stored in the capacitors C10 and C11 when the corresponding photovoltaic input source 10 is disconnected.

[0035] It should be noted that when the corresponding photovoltaic input source 10 is disconnected from the first control module 22, the energy stored in the capacitors C10 and C11 is discharged through the first discharge unit 223, thereby ensuring that the first signal generation unit 221 can output the first control signal normally when the corresponding photovoltaic input source 10 is detected next time.

[0036] In yet another embodiment, such as Figure 3 As shown, the first discharge unit 223 is a resistor R29. The first end of the resistor R29 is connected to the capacitor C10, and the second end of the resistor R29 is connected to the ground terminal.

[0037] It is known that when the corresponding photovoltaic input source 10 is disconnected from the first control module 22, the capacitor C10 will discharge through the resistor R29. When the voltage difference between the voltage stored in the capacitor C10 and the voltage stored in the capacitor C11 is greater than the forward voltage drop of the diode D5, the capacitor C11 will also start to discharge rapidly through the resistor R29.

[0038] In some embodiments, such as Figure 3 As shown, the first signal generation unit 221 further includes a Zener diode DZ1; the cathode of the Zener diode DZ1 is connected to the corresponding photovoltaic input source 10, and the anode of the Zener diode DZ1 is connected to the first terminal of the switching transistor Q5. The Zener diode DZ1 is used to detect the input voltage of the photovoltaic input source 10, and when the input voltage is less than the Zener value of the Zener diode DZ1, it stops transmitting the input voltage of the photovoltaic input source 10 to the switching transistor Q5. Based on this, insulation testing of the photovoltaic input source 10 can be stopped when the input voltage of the corresponding photovoltaic input source 10 does not meet the requirements, thereby improving the accuracy of the detection.

[0039] In some embodiments, please refer to Figure 4 , Figure 4 This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention, as shown below. Figure 4 As shown, the delay module 24 includes a capacitor C7, a resistor R22, and a Zener diode DZ3; The resistor R22 is connected to the capacitor C7 and the corresponding photovoltaic input source 10 respectively. The capacitor C7 is also connected to the cathode of the Zener diode DZ3 and is also used for grounding. The anode of the Zener diode DZ3 is connected to the second control module 23.

[0040] Specifically, when the corresponding photovoltaic input source 10 outputs the input voltage, the input voltage charges the capacitor C7 through the resistor R22. When the energy stored in the capacitor C7 exceeds the voltage regulation value of the Zener diode DZ3, the Zener diode DZ3 breaks down. At this time, the input voltage of the photovoltaic input source 10 is transmitted to the second control module 23, causing the second control module 23 to start working. It should be noted that by changing the capacitance value of the capacitor C7, the resistance value of the resistor R22, and the voltage regulation value of the Zener diode DZ3, the input voltage received from the corresponding photovoltaic input source 10 can be delayed by different target times before being output to the corresponding second control module 23. When setting the capacitance value of the capacitor C7, the resistance value of the resistor R22, and the voltage regulation value of the Zener diode DZ3, it is necessary to ensure that the Zener diode DZ3 is not broken down when the first control module 22 or the preceding second control module 23 is working, so that multiple photovoltaic input sources 10 can sequentially perform insulation impedance detection.

[0041] In some embodiments, such as Figure 2 As shown, the second control module 23 includes a second signal generation unit 231 and a second switching unit 232; The second signal generation unit 231 is connected to the delay module 24 and the second switching unit 232 respectively, and the second switching unit 232 is connected to the detection module 21 and the corresponding photovoltaic input source 10 respectively; The second signal generation unit 231 is used to receive and store the input voltage of the corresponding photovoltaic input source 10, and output a second control signal based on the stored voltage; and The output of the second control signal is stopped when the stored voltage is greater than the second preset value; The second switching unit 232 is configured to, upon receiving the second control signal, turn on based on the second control signal to connect the connected photovoltaic input source 10 to the detection module 21; and When the second control signal is not received, the circuit is turned off to disconnect the detection loop between the connected photovoltaic input source 10 and the detection module 21.

[0042] Specifically, when the photovoltaic input source 10 outputs the input voltage, the delay module 24 receives the input voltage and delays it by a target time before inputting it to the second control module 23. By delaying the input voltage by the target time, it ensures that the downstream photovoltaic input source 10 will not perform insulation impedance testing when the upstream photovoltaic input source 10 is performing insulation impedance testing. When the second control module 23 receives the input voltage, the second signal generation unit 231 stores the input voltage and outputs a second control signal based on it. After a second preset time, if the voltage stored by the second signal generation unit 231 exceeds a second preset value, the second signal generation unit 231 will stop outputting the second control signal. Based on this, the second signal generation unit 231 can then output a second control signal for the second preset time.

[0043] When the second signal generation unit 231 outputs a second control signal for a second preset time, the second switch unit 232 receives the second control signal and conducts for the duration of the second control signal. When the second switch unit 232 is on, the current photovoltaic input source 10 is connected to the detection module 21 through the second switch unit 232, thereby detecting the insulation resistance of the corresponding photovoltaic input source 10 based on the detection module 21. If the second switch unit 232 does not receive the second control signal, the second switch unit 232 is in the off state, thereby disconnecting the current photovoltaic input source 10 from the detection module 21, and thus breaking the detection loop between the connected photovoltaic input source 10 and the detection module 21. Based on this, when the photovoltaic input source 10 connected to the first control module 22 or the photovoltaic input source 10 connected to the upper-level second control module 23 is undergoing insulation testing, the current photovoltaic input source 10 is prevented from being connected to the detection module 21, allowing multiple photovoltaic input sources 10 to be tested sequentially, thereby reducing testing costs and testing difficulty.

[0044] In yet another embodiment, such as Figure 4 As shown, the second switching unit 232 includes a switching transistor Q4, a switching transistor Q8, a resistor R25, and a resistor R21; the second signal generation unit 231 includes a switching transistor Q6, a resistor R27, a diode D6, a capacitor C9, a capacitor C12, and a capacitor C13. The first terminal of the switching transistor Q6 is connected to the corresponding delay module 24. The first terminal of the switching transistor Q6 is also connected to the control terminal of the switching transistor Q6 through the resistor R27. The control terminal of the switching transistor Q6 is also grounded through the capacitor C13. The control terminal of the switching transistor Q6 is also connected to the anode of the diode D6. The cathode of the diode D6 is grounded through the capacitor C12. The second terminal of the switching transistor Q6 is grounded through the capacitor C9. The second terminal of the switching transistor Q6 is also connected to the second switching unit 232.

[0045] The control terminal of the switch Q8 is connected to the second signal generation unit 231. The first terminal of the switch Q8 is connected to the control terminal of the switch Q4 through the resistor R25. The second terminal of the switch Q8 is used for grounding. The first terminal of the switch Q4 is connected to the corresponding photovoltaic input source 10. The first terminal of the switch Q4 is also connected to the control terminal of the switch Q4 through the resistor R21. The second terminal of the switch Q4 is connected to the detection module 21.

[0046] It should be noted that the working principle of the second signal generation unit 231 and the second switching unit 232 is similar to that of the first signal generation unit 221 and the first switching unit 222, and will not be described again here.

[0047] In another embodiment, the second control module 23 further includes a second discharge unit 233, which is connected to the second signal generation unit 231. The second discharge unit 233 is used to quickly discharge the capacitors C12 and C13 to ensure that the second signal generation unit 231 can correctly output the second control signal for the second preset time next time.

[0048] The structure and working principle of the second discharge unit 233 are similar to those of the first discharge unit 223, and will not be described in detail here.

[0049] In some embodiments, the energy storage system 100 further includes a controller connected to the detection module 21. See also... Figure 5 , Figure 5 This is a circuit diagram of a detection module provided in an embodiment of the present invention, such as... Figure 5 As shown, the detection module 21 includes relays RLY1 and RLY2, operational amplifier U1, resistors R1, R3, R7, R10, R12, R15, R17, and switching transistors Q1 and Q2. The coil terminal of relay RLY1 is connected to the power supply and the first terminal of switching transistor Q1, respectively. The connection terminal of relay RLY1 is connected to resistors R3 and R7, respectively. The control terminal of switching transistor Q1 is connected to the controller. The second terminal of switching transistor Q1 is grounded. Resistor R3 is also connected to the first control module 22 or the second control module 23 through resistor R1. Resistor R3 is also connected to resistor R10. Resistor R10 is also connected to resistor R17 and the connection terminal of relay RLY2 through resistor R15, respectively. The connection terminal of relay RLY2 and resistor R17 are both grounded. The coil terminal of relay RLY2 is connected to the power supply and the first terminal of switching transistor Q2, respectively. The control terminal of switching transistor Q2 is connected to the controller. The second terminal of switching transistor Q2 is also grounded. The first input terminal of operational amplifier U1 is connected to resistor R7. The second input terminal of operational amplifier U1 is also grounded through resistor R12. The output terminal of operational amplifier U1 is connected to the controller.

[0050] Specifically, when the first switching unit 222 is turned on, the detection module 21 connects to the photovoltaic input source 10 through the first switching unit 222. At this time, the controller outputs a first drive signal (RLY2 ISO) to control the switching transistor Q1 to turn on, so that the relay RLY1 closes. When the relay RLY1 closes, the resistors R1, R3, R15, and R17 simultaneously divide the input voltage and output the first voltage divider signal (the voltage divider values ​​on resistors R15 and R17) to the first input terminal of the operational amplifier U1. When the operational amplifier U1 receives the first voltage divider signal, it outputs a first sampled value to the controller (MCU) based on the first voltage divider signal. After receiving the first sampled value, the controller turns on both switches Q1 and Q2 (i.e., outputs a first drive signal to switch Q1 and a second drive signal (RLY1 ISO) to switch Q2). When both switches Q1 and Q2 are turned on, both relays RLY1 and RLY2 are closed. At this time, resistor R17 is short-circuited, and resistors R1, R3, and R15 divide the input voltage, outputting a second voltage divider signal (the voltage divider value on resistor R15) to the first input terminal of operational amplifier U1, so that operational amplifier U1 outputs a second sampled value to the controller.

[0051] In some embodiments, after the controller receives the first sampled value and the second sampled value, it can calculate the insulation impedance of the current photovoltaic input source 10 based on the first sampled value and the second sampled value. When the insulation impedance is less than a preset range, it determines that the corresponding photovoltaic input source 10 has failed, and the controller will output a fault signal. Based on this, it is possible to accurately determine whether the current photovoltaic input source 10 is operating stably, thereby improving the reliability of the energy storage system 100.

[0052] It is understood that, since the energy storage system 100 includes multiple photovoltaic input sources 10, and these multiple photovoltaic input sources 10 sequentially pass through the detection module 21 for insulation resistance detection and input the detection results to the controller, when the detection module 21 sequentially detects multiple photovoltaic input sources 10 and inputs the detection results to the controller, if a photovoltaic input source 10 malfunctions, it may be impossible to accurately determine which photovoltaic input source 10 is faulty. This results in the inability to promptly address the faulty photovoltaic input source 10, thereby reducing the reliability and safety of the energy storage system. Based on this, please refer to... Figure 6 , Figure 6 This is a structural block diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention, as shown below. Figure 6As shown, taking two fault location modules 25 as an example, the photovoltaic insulation impedance detection circuit 20 also includes at least two fault location modules 25; The at least two fault location modules 25 are respectively connected to the first control module 22 and at least one second control module 23, and the at least two fault location modules 25 are also connected to the detection module 21. The fault location module 25 is used to output an indication signal when it receives the first control signal output by the corresponding first control module 22 or the second control signal output by the second control module 23 and the fault signal, so as to indicate that the connected photovoltaic input source 10 is faulty.

[0053] When the controller determines that the photovoltaic input source 10 has malfunctioned based on the first and second sampled values, the controller outputs a fault signal. At least two fault location modules 25 will also receive the fault signal. If a fault location module 25 receives a first control signal output by the first control module 22 or a second control signal output by the second control module 23, the corresponding fault location module 25 will output an indication signal based on the fault signal and the first / second control signal to indicate that the photovoltaic input source 10 corresponding to the first / second control module 22 has malfunctioned. Based on this, when a fault is detected in the photovoltaic input source 10, the faulty photovoltaic input source 10 can be quickly identified, thereby improving the safety and reliability of the energy storage system 100.

[0054] In some embodiments, please refer to Figures 7a-7c , Figures 7a-7c This is a circuit diagram of a photovoltaic insulation impedance detection circuit provided in another embodiment of the present invention, as shown below. Figure 7a As shown, the fault location module 25 includes an AND gate U2B, a resistor R62, a resistor R63, a switch Q27, and a diode LED1; The first input terminal of the AND gate U2B is connected to the first control module 22, the second input terminal of the AND gate U2B is connected to the detection module 21, the output terminal of the AND gate U2B is connected to the control terminal of the switch Q27 through the resistor R62, the control terminal of the switch Q27 is also grounded through the resistor R63, the first terminal of the switch Q27 is connected to the cathode of the diode LED1, the second terminal of the switch Q27 is used for grounding, and the anode of the diode LED1 is connected to the first power supply.

[0055] When the first control module 22 outputs the first control signal, the first input terminal of the AND gate U2B receives the first control signal. At this time, if the controller does not output a fault signal (ISO Fault), the AND gate U2B outputs a low-level signal, the switch Q27 is turned off, and the diode LED1 does not indicate. If the controller outputs a fault signal, the AND gate U2B outputs a high-level signal, the switch Q27 is turned on, and the diode LED1 outputs an indicator signal.

[0056] It is understood that the state of the diode LED1 is only for distinguishing whether the current photovoltaic input source 10 is faulty, and its specific indication form is not limited here. For example, it can be indicated by whether the diode LED1 is on or off, or by the color of the diode LED1.

[0057] In other embodiments, the fault location module 25 may also input the indication signal to the controller so that the controller indicates which photovoltaic input source 10 has failed.

[0058] In another embodiment, when a photovoltaic input source 10 fails, to prevent that photovoltaic input source 10 from affecting other photovoltaic input sources, such as... Figure 6 As shown, taking two ground control modules 26 as an example, the photovoltaic insulation impedance detection circuit 20 also includes at least two ground control modules 26; The at least two ground control modules 26 are respectively connected to the first control module 22 and at least one second control module 23, and the at least two ground control modules 26 are also connected to the detection module 21; The at least two ground control modules 26 are used to receive the first control signal output by the first control module 22 or the second control signal output by the second control module 23 connected to them, and start working based on the first control signal or the second control signal so that the negative terminal of the corresponding photovoltaic input source 10 is connected to the detection module 21.

[0059] In some embodiments, such as Figures 7b-7c As shown, the ground control module 26 includes a relay RLY3, a resistor R59, and a switching transistor Q24; The control terminal of the switching transistor Q24 is connected to the first control module 22. The control terminal of the switching transistor Q24 is also connected to the ground terminal of the detection module 21 through the resistor R59. The first terminal of the switching transistor Q24 is connected to the ground terminal of the detection module 21. The second terminal of the switching transistor Q24 is connected to the coil terminal of the relay RLY3. The coil terminal of the relay RLY3 is also connected to the power supply. The connection terminal of the relay RLY3 is connected to the negative terminal of the corresponding photovoltaic input source 10 and the ground terminal of the detection module 21, respectively.

[0060] Specifically, when the first control module 22 outputs the first control signal, the first control signal is also input to the control terminal of the switching transistor Q24 to turn on the switching transistor Q24. When the switching transistor Q24 is turned on, the coil terminal of the relay RLY3 is energized, and the relay RLY3 is closed, so that the negative terminal of the photovoltaic input source 10 is connected to the ground terminal of the detection module 21.

[0061] This invention provides a photovoltaic insulation impedance detection circuit, which includes a detection module, a first control module, at least one second control module, and at least one delay module. The first control module and each of the second control modules are respectively connected to the detection module and a corresponding photovoltaic input source. Each of the second control modules is also connected to a corresponding delay module. The first control module and each of the delay modules are also respectively connected to a photovoltaic input source. The first control module outputs a first control signal for a first preset time when the photovoltaic input source is connected, and controls the connected photovoltaic input source to connect to the detection module within the duration of the first control signal, so that the detection module can accurately and stably complete the detection of the insulation impedance of the photovoltaic input source within the preset time. Each delay module receives the input voltage of the connected photovoltaic input source and inputs the input voltage to the corresponding second control module after delaying the input voltage by a target time. When there are at least two delay modules, the target time of each delay module is different, thereby automatically forming a non-overlapping detection sequence, avoiding mutual interference between signals, and achieving orderly switching without additional complex control logic. Each second control module outputs a second control signal for a second preset time when the input voltage is received, and controls the connected photovoltaic input source to connect to the detection module within the duration of the second control signal, so that the detection module can sequentially and time-divisionally complete the detection of the insulation impedance of each photovoltaic input source. Multi-channel detection is achieved using only one set of detection modules, effectively simplifying the circuit structure, reducing hardware costs, and improving the system's versatility and practicality.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic insulation impedance detection circuit, characterized in that, The photovoltaic insulation impedance detection circuit includes a detection module, a first control module, at least one second control module, and at least one delay module. The first control module and each of the second control modules are respectively connected to the detection module and the corresponding photovoltaic input source. Each of the second control modules is also connected to a corresponding delay module. The first control module and each of the delay modules are also respectively connected to a photovoltaic input source. The first control module is used to output a first control signal for a first preset time when the photovoltaic input source is connected, and to control the connected photovoltaic input source to connect to the detection module during the duration of the first control signal, so that the detection module can detect the insulation impedance of the connected photovoltaic input source; Each of the delay modules is used to receive the input voltage of the connected photovoltaic input source and input the input voltage to the corresponding second control module after delaying the input voltage by a target time. When there are at least two delay modules, the target time of each delay module is different. Each of the second control modules is configured to output a second control signal for a second preset time when receiving the input voltage, and control the connected photovoltaic input source to connect to the detection module during the duration of the second control signal, so that the detection module can detect the insulation impedance of the connected photovoltaic input source.

2. The photovoltaic insulation impedance detection circuit according to claim 1, characterized in that, The first control module includes a first signal generation unit and a first switching unit; The first signal generation unit is connected to the first switching unit and the corresponding photovoltaic input source, and the first switching unit is connected to the detection module and the corresponding photovoltaic input source. The first signal generation unit is used to receive and store the input voltage of the photovoltaic input source when the photovoltaic input source is connected, and output a first control signal based on the stored voltage; as well as The first control signal is stopped being output when the stored voltage is greater than the first preset value; The first switching unit is used to turn on based on the first control signal when it receives the first control signal, so as to connect the connected photovoltaic input source to the detection module; as well as The system shuts down when the first control signal is not received, thereby disconnecting the photovoltaic input source from the detection module.

3. The photovoltaic insulation impedance detection circuit according to claim 2, characterized in that, The first switching unit includes switching transistor Q3, switching transistor Q7, resistor R20, and resistor R23; The control terminal of the switch Q7 is connected to the first signal generation unit. The first terminal of the switch Q7 is connected to the control terminal of the switch Q3 through the resistor R23. The second terminal of the switch Q7 is grounded. The first terminal of the switch Q3 is connected to the corresponding photovoltaic input source. The first terminal of the switch Q3 is also connected to the control terminal of the switch Q3 through the resistor R20. The second terminal of the switch Q3 is connected to the detection module.

4. The photovoltaic insulation impedance detection circuit according to claim 2, characterized in that, The first signal generation unit includes a switch Q5, a resistor R24, a diode D5, a capacitor C8, a capacitor C10, and a capacitor C11; The first terminal of the switch Q5 is connected to the corresponding photovoltaic input source. The first terminal of the switch Q5 is also connected to the control terminal of the switch Q5 through the resistor R24. The control terminal of the switch Q5 is also grounded through the capacitor C11. The control terminal of the switch Q5 is also connected to the anode of the diode D5. The cathode of the diode D5 is also grounded through the capacitor C10. The capacitor C10 is also connected to the corresponding photovoltaic input source. The second terminal of the switch Q5 is grounded through the capacitor C8. The second terminal of the switch Q5 is also connected to the first switching unit.

5. The photovoltaic insulation impedance detection circuit according to claim 4, characterized in that, The first control module further includes a first discharge unit; The first discharge unit is connected to the cathode of the diode D5; The first discharge unit is used to discharge the energy stored in the capacitors C10 and C11 when the corresponding connected photovoltaic input source is disconnected.

6. The photovoltaic insulation impedance detection circuit according to claim 4, characterized in that, The first signal generation unit also includes a Zener diode DZ1; The cathode of the Zener diode DZ1 is connected to the corresponding photovoltaic input source, and the anode of the Zener diode DZ1 is connected to the first end of the switching transistor Q5.

7. The photovoltaic insulation impedance detection circuit according to any one of claims 1-6, characterized in that, The delay module includes a capacitor C7, a resistor R22, and a Zener diode DZ3; The resistor R22 is connected to the capacitor C7 and the corresponding photovoltaic input source respectively. The capacitor C7 is also connected to the cathode of the Zener diode DZ3. The capacitor C7 is also used for grounding. The anode of the Zener diode DZ3 is connected to the second control module.

8. The photovoltaic insulation impedance detection circuit according to claim 7, characterized in that, The photovoltaic insulation impedance detection circuit also includes at least two fault location modules; The at least two fault location modules are respectively connected to the first control module and at least one second control module, the at least two fault location modules are also connected to the detection module, and the at least two fault location modules are also used to receive fault signals; The fault location module is used to output an indication signal when it receives the first control signal output by the corresponding first control module or the second control signal output by the second control module and the fault signal, so as to indicate that the connected photovoltaic input source is faulty.

9. The photovoltaic insulation impedance detection circuit according to claim 7, characterized in that, The detection module includes relays RLY1 and RLY2, operational amplifier U1, resistors R1, R3, R7, R10, R12, R15, R17, and switching transistors Q1 and Q2. The coil terminal of relay RLY1 is connected to the power supply and the first terminal of switching transistor Q1, respectively. The connection terminal of relay RLY1 is connected to resistors R3 and R7, respectively. The control terminal of switching transistor Q1 is connected to the controller. The second terminal of switching transistor Q1 is grounded. Resistor R3 is also connected to the first control module or at least one second control module through resistor R1. Resistor R3 is also connected to resistor R10. Resistor R10 is also connected to resistor R17 and the connection terminal of relay RLY2 through resistor R15, respectively. The connection terminal of relay RLY2 and resistor R17 are both grounded. The coil terminal of relay RLY2 is connected to the power supply and the first terminal of switching transistor Q2, respectively. The control terminal of switching transistor Q2 is connected to the controller. The second terminal of switching transistor Q2 is also grounded. The first input terminal of operational amplifier U1 is connected to resistor R7. The second input terminal of operational amplifier U1 is also grounded through resistor R12. The output terminal of operational amplifier U1 is connected to the controller.

10. An energy storage system, characterized in that, The energy storage system includes: Multiple photovoltaic input sources; and The photovoltaic insulation impedance detection circuit according to any one of claims 1-9 is connected to a plurality of photovoltaic input sources respectively.

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