Leakage protection circuit and energy storage system

Abstract

The application relates to a leakage protection circuit and an energy storage system. The leakage protection circuit comprises a leakage detection module, a component passing module, a threshold setting module and a protection module; the leakage detection module is used for outputting a leakage detection voltage of a power supply circuit; the component passing module is used for passing a slow-varying voltage component and a transient voltage component in the leakage detection voltage; the threshold setting module is used for detecting an ambient humidity voltage, outputting a target voltage threshold value matched with a target voltage threshold value interval among a plurality of voltage threshold value intervals in which the ambient humidity voltage is located, based on the target voltage threshold value interval; and the protection module is used for driving the power supply circuit to be disconnected when the slow-varying voltage component is greater than the target voltage threshold value, and / or when the transient voltage component is greater than a preset voltage threshold value. The application can improve the environmental adaptability and operation reliability of the leakage protection circuit.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a leakage current protection circuit and an energy storage system. Background Technology

[0002] With the rapid development of the new energy industry, the application scope of energy storage systems is becoming more and more extensive. However, leakage risks affect the safety of energy storage systems, so it is very important to protect energy storage systems from leakage.

[0003] Traditional leakage current protection schemes often set a fixed leakage current threshold. When the detected leakage current value of the energy storage system exceeds this threshold, the power supply circuit of the energy storage system is disconnected. However, when the energy storage system operates in a humid environment, the detected leakage current value is more likely to exceed the set leakage current threshold. In this case, disconnecting the power supply circuit of the energy storage system will cause the energy storage system to stop supplying power.

[0004] Therefore, traditional leakage protection solutions suffer from poor environmental adaptability. Summary of the Invention

[0005] Based on this, this application provides a leakage current protection circuit and an energy storage system, which can improve the environmental adaptability and operational reliability of the leakage current protection circuit.

[0006] In a first aspect, this application provides a leakage current protection circuit, which includes: a leakage current detection module, a component transmission module, a threshold setting module, and a protection module; the input terminal of the leakage current detection module is connected to a power supply circuit, the output terminal of the leakage current detection module is connected to the input terminal of the component transmission module, the output terminal of the component transmission module is connected to the component input terminal of the protection module, the threshold input terminal of the protection module is connected to the threshold setting module, and the output terminal of the protection module is connected to the power supply circuit.

[0007] The leakage current detection module is used to output the leakage current detection voltage of the power supply circuit;

[0008] The components are passed through the module to detect the slowly varying voltage component and the transient voltage component in the leakage current detection voltage;

[0009] The threshold setting module is used to detect ambient humidity voltage and output a target voltage threshold that matches the target voltage threshold range among multiple voltage threshold ranges in which the ambient humidity voltage is located.

[0010] The protection module is used to drive the power supply circuit to disconnect when the slowly varying voltage component exceeds the target voltage threshold, and / or when the transient voltage component exceeds the preset voltage threshold.

[0011] In some embodiments, the protection module includes a first comparison unit, a second comparison unit, and a driving unit;

[0012] The first input terminal of the first comparison unit is connected to the gradually changing component output terminal of the component through the module, the second input terminal of the first comparison unit is connected to the output terminal of the threshold setting module, and the output terminal of the first comparison unit is connected to the first input terminal of the drive unit, which is used to output a first protection signal when the gradually changing voltage component is greater than the target voltage threshold.

[0013] The first input terminal of the second comparison unit is connected to the transient component output terminal of the component through the module. The voltage of the second input terminal of the second comparison unit is a preset voltage threshold. The output terminal of the second comparison unit is connected to the second input terminal of the drive unit, and is used to output a second protection signal when the transient voltage component is greater than the preset voltage threshold.

[0014] The drive unit is used to disconnect the power supply circuit when a first protection signal and / or a second protection signal are received.

[0015] In some embodiments, the component passing module includes a slowly varying component passing unit and a transient component passing unit;

[0016] The gradually changing component is connected to the output of the leakage current detection module through the input terminal of the unit, and the gradually changing component is connected to the component input terminal of the protection module through the output terminal of the unit, which is used to detect the gradually changing voltage component in the leakage current detection voltage.

[0017] The transient component is connected to the output of the leakage current detection module through the input terminal of the unit, and the transient component is connected to the component input terminal of the protection module through the output terminal of the unit, and is used to detect the transient voltage component in the leakage current detection voltage.

[0018] In some embodiments, the gradually varying component passing unit includes a low-pass filter and a first voltage follower; the input of the low-pass filter is connected to the output of the leakage current detection module, the output of the low-pass filter is connected to the input of the first voltage follower, and the output of the first voltage follower is connected to the component input of the protection module.

[0019] The transient component passing unit includes a high-pass filter and a second voltage follower; the input of the high-pass filter is connected to the output of the leakage current detection module, the output of the high-pass filter is connected to the input of the second voltage follower, and the output of the second voltage follower is connected to the component input of the protection module.

[0020] In some embodiments, the threshold setting module includes a humidity detection unit and a threshold output unit; the input terminal of the threshold output unit is connected to the humidity detection unit, and the output terminal of the threshold output unit is connected to the threshold input terminal of the protection module.

[0021] Humidity detection unit, used to detect ambient humidity voltage;

[0022] The threshold output unit is used to output a target voltage threshold that matches the target voltage threshold range among multiple voltage threshold ranges in which the ambient humidity voltage is located.

[0023] In some embodiments, the humidity detection unit includes a humidity sampling subunit, a first rectifier subunit, and a first amplification subunit; the input terminal of the first rectifier subunit is connected to the humidity sampling subunit, the output terminal of the first rectifier subunit is connected to the input terminal of the first amplification subunit, and the output terminal of the first amplification subunit is connected to the input terminal of the threshold output unit.

[0024] Humidity sampling subunit is used to output alternating voltage for ambient humidity;

[0025] The first rectifier subunit is used to rectify the ambient humidity alternating voltage and output the ambient humidity rectified voltage.

[0026] The first amplification subunit is used to amplify the rectified voltage of ambient humidity to obtain the ambient humidity voltage.

[0027] In some embodiments, the threshold output unit includes a first comparison subunit, a second comparison subunit, and a threshold output subunit;

[0028] The first input terminal of the first comparison subunit is connected to the output terminal of the humidity detection unit. The voltage of the second input terminal of the first comparison subunit is the first voltage threshold. The output terminal of the first comparison subunit is connected to the first input terminal of the threshold output subunit and is used to output a first comparison signal between the ambient humidity voltage and the first voltage threshold.

[0029] The first input terminal of the second comparison subunit is connected to the output terminal of the humidity detection unit. The voltage at the second input terminal of the second comparison subunit is the second voltage threshold. The output terminal of the second comparison subunit is connected to the second input terminal of the threshold output subunit, and is used to output a second comparison signal between the ambient humidity voltage and the second voltage threshold.

[0030] The threshold output subunit is used to output a target voltage threshold based on a first comparison signal and a second comparison signal.

[0031] In some embodiments, the leakage current detection module includes a zero-sequence current transformer, a sampling resistor, and a leakage current output unit; the primary side of the zero-sequence current transformer passes through the power supply circuit, the secondary side of the zero-sequence current transformer is connected in parallel with the sampling resistor, the secondary side of the zero-sequence current transformer is also connected to the input terminal of the leakage current output unit, and the output terminal of the leakage current output unit is connected to the input terminal of the component passing through the module.

[0032] Zero-sequence current transformers are used to sense the leakage current in power supply circuits and output a leakage AC voltage that is compatible with the leakage current.

[0033] The leakage current output unit is used to convert leakage current AC voltage into leakage current detection voltage.

[0034] In some embodiments, the leakage current output unit includes a second amplification subunit, a second rectification subunit, and a filtering subunit; the input terminal of the second amplification subunit is connected to the secondary side of the zero-sequence current transformer, the output terminal of the second amplification subunit is connected to the input terminal of the second rectification subunit, the output terminal of the second rectification subunit is connected to the input terminal of the filtering subunit, and the output terminal of the filtering subunit is connected to the input terminal of the component passing module.

[0035] The second amplification subunit is used to amplify the leakage AC voltage to obtain the leakage AC amplified voltage;

[0036] The second rectifier subunit is used to rectify the leakage AC amplified voltage to obtain the leakage rectified voltage;

[0037] The filtering subunit is used to filter the leakage current rectified voltage to obtain the leakage current detection voltage.

[0038] Secondly, this application provides an energy storage system, which includes a power supply circuit and a leakage protection circuit as described in any of the first aspects, connected to the power supply circuit.

[0039] In the technical solution provided in this application embodiment, the leakage detection module outputs the leakage detection voltage of the power supply circuit in real time. The components are separated and transmitted by the module, and the slowly changing voltage component and the transient voltage component are transmitted. This can accurately distinguish between the gradual leakage signal caused by the slow change of ambient humidity and the instantaneous fault leakage signal, thus achieving refined identification of the leakage signal. The threshold setting module outputs a target voltage threshold that matches the target voltage threshold range among multiple voltage threshold ranges where the real-time detected ambient humidity voltage is located. This allows the leakage protection judgment standard to be adaptively adjusted according to the environmental conditions, effectively avoiding the problem of the slowly changing voltage component erroneously triggering the protection action of the power supply circuit due to the slow decrease of insulation in rainy or humid scenarios. The protection module executes the leakage protection of the power supply circuit based on the comparison results of the slowly changing voltage component and the target voltage threshold and the comparison results of the transient voltage component and the preset voltage threshold. This can not only act quickly when instantaneous fault leakage occurs, but also reasonably identify the gradual leakage caused by the environment, reduce non-fault power outages, and take into account both the continuity of energy storage system operation and leakage protection safety, thereby improving the environmental adaptability and operational reliability of the energy storage system. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the leakage current protection circuit provided in the first embodiment;

[0042] Figure 2 A schematic diagram of the leakage protection circuit provided in the second embodiment;

[0043] Figure 3 A schematic diagram of the leakage protection circuit provided in the third embodiment;

[0044] Figure 4 A schematic diagram of the circuit structure of the threshold setting module provided in the first embodiment;

[0045] Figure 5 A schematic diagram of the circuit structure of the threshold setting module provided in the second embodiment;

[0046] Figure 6 A schematic diagram of the circuit structure of the leakage current detection module provided in the first embodiment;

[0047] Figure 7 A schematic diagram of the circuit structure of the leakage current detection module provided in the second embodiment;

[0048] Figure 8 A circuit diagram of an energy storage system provided for some embodiments. Detailed Implementation

[0049] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0051] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. In the description of the embodiments of this application, "each" means each of the multiple options, unless otherwise explicitly defined.

[0052] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0053] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] The risk of leakage current in energy storage systems affects their safety, making leakage protection crucial. Taking photovoltaic (PV) energy storage systems as an example, these systems can be deployed on rooftops, balconies, or open outdoor spaces. Exposed to the natural environment, PV systems face complex conditions such as rain and humidity; therefore, leakage protection is essential for ensuring their reliable operation. It should be noted that the energy storage system in this embodiment is not limited to PV systems; it can also include other energy storage systems, such as wind power energy storage systems or battery energy storage systems.

[0056] In some situations, when the detected leakage current value of the energy storage system exceeds the leakage current action threshold, the power supply circuit of the energy storage system is disconnected. Although this scheme can prevent leakage of the energy storage system, in rainy or humid weather, the detected leakage current value of the energy storage system is likely to exceed the set leakage current action threshold. In this case, the disconnection of the power supply circuit of the energy storage system will cause the energy storage system to stop supplying power. This leakage protection scheme has the problem of poor environmental adaptability, which affects the operational stability of the energy storage system.

[0057] Based on this, the embodiments of this application provide a leakage current protection circuit, which can improve the environmental adaptability and operational reliability of the leakage current protection circuit.

[0058] Figure 1 A schematic diagram of the leakage current protection circuit provided in the first embodiment is shown below. Figure 1 As shown, the leakage protection circuit includes: a leakage detection module, a component transmission module, a threshold setting module, and a protection module.

[0059] The input terminal of the leakage current detection module is connected to the power supply circuit, the output terminal of the leakage current detection module is connected to the input terminal of the component current detection module, the output terminal of the component current detection module is connected to the component input terminal of the protection module, the threshold input terminal of the protection module is connected to the threshold setting module, and the output terminal of the protection module is connected to the power supply circuit.

[0060] The system includes a leakage current detection module for outputting a leakage current detection voltage from the power supply circuit; a component passing module for passing the slowly varying voltage component and the transient voltage component in the leakage current detection voltage; a threshold setting module for detecting the ambient humidity voltage and, based on the target voltage threshold range among multiple voltage threshold ranges where the ambient humidity voltage is located, outputting a target voltage threshold that matches the target voltage threshold range; and a protection module for driving the power supply circuit to disconnect when the slowly varying voltage component exceeds the target voltage threshold and / or when the transient voltage component exceeds a preset voltage threshold.

[0061] In some embodiments, the protection module is further configured to drive the power supply circuit to conduct when the slowly varying voltage component is less than or equal to a target voltage threshold, and when the transient voltage component is less than or equal to a preset voltage threshold. Here, the power supply circuit being conducted is the default state of the power supply circuit.

[0062] A power supply circuit can be a power supply circuit that supplies power to a load from photovoltaic modules in an energy storage system. Exemplarily, the power supply circuit has an input terminal and an output terminal, and a power supply switch is provided in the power supply circuit. The input terminal of the power supply circuit is connected to the output terminal of the power supply circuit through the power supply switch. The power supply switch can be a switch between the photovoltaic module and the inverter, or it can include a switch in the inverter, or it can include a switch between the inverter and the output terminal of the power supply circuit. In the embodiments of this application, when the power supply switch is on, the input terminal of the power supply circuit can supply power to the output terminal of the power supply circuit; when the power supply switch is off, the input terminal of the power supply circuit stops supplying power to the output terminal of the power supply circuit.

[0063] The leakage current detection voltage can be a voltage representing the magnitude of the leakage current in the power supply circuit. The leakage current detection voltage can be positively correlated with the leakage current. For example, a leakage current detection module is used to detect the leakage current in the power supply circuit, convert the leakage current into a leakage current detection voltage, and output the leakage current detection voltage of the power supply circuit. As another example, a leakage current detection module is used to detect the leakage current detection voltage of the power supply circuit and output the leakage current detection voltage of the power supply circuit.

[0064] The slowly varying voltage component in leakage current detection voltage refers to the portion of the detection voltage that changes slowly over time due to the gradual changes in environmental factors such as humidity and condensation. For example, in the slowly varying voltage component of leakage current detection voltage, the difference between the maximum and minimum voltage per unit time is less than or equal to a first set voltage threshold.

[0065] The transient voltage component in the leakage current detection voltage refers to the voltage component that changes rapidly within a short period of time due to transient and abrupt factors. When the leakage current detection voltage exceeds a preset voltage threshold, it indicates that there is a leakage current fault, a momentary short circuit, switching interference, lightning strike, or electromagnetic pulse in the power supply circuit. For example, in the transient voltage component of the leakage current detection voltage, the difference between the maximum and minimum voltages within a unit time period is greater than a second preset voltage threshold. Exemplarily, the first preset voltage threshold and the second preset voltage threshold can be the same. Also exemplaryly, the first preset voltage threshold can be less than the second preset voltage threshold.

[0066] For example, multiple consecutive voltage threshold intervals can be preset, and a voltage threshold can be matched to each voltage threshold interval. The threshold setting module can output a target voltage threshold that matches the target voltage threshold interval where the ambient humidity voltage is located, based on the target voltage threshold interval where the ambient humidity voltage is located. The target voltage threshold interval is one of the multiple voltage threshold intervals. In some embodiments, the voltages in different voltage threshold intervals do not overlap, and the union of multiple voltage threshold intervals is a continuous and uninterrupted voltage interval. Different voltage threshold intervals match different target voltage thresholds. For example, the higher the ambient humidity, the higher the target voltage threshold.

[0067] If the gradually changing voltage component exceeds the target voltage threshold, it indicates that the progressive leakage current caused by environmental factors such as humidity and condensation has exceeded the allowable range, posing a leakage risk to the power supply circuit and requiring immediate triggering of protection actions. If the transient voltage component exceeds the preset voltage threshold, it indicates a sudden, transient leakage fault, representing a genuine leakage anomaly, and requiring immediate triggering of protection actions.

[0068] In the technical solution provided in this application embodiment, the leakage detection module outputs the leakage detection voltage of the power supply circuit in real time. The components are separated and transmitted by the module, and the slowly changing voltage component and the transient voltage component are transmitted. This can accurately distinguish between the gradual leakage signal caused by the slow change of ambient humidity and the instantaneous fault leakage signal, thus achieving refined identification of the leakage signal. The threshold setting module outputs a target voltage threshold that matches the target voltage threshold range among multiple voltage threshold ranges where the real-time detected ambient humidity voltage is located. This allows the leakage protection judgment standard to be adaptively adjusted according to the environmental conditions, effectively avoiding the problem of the slowly changing voltage component erroneously triggering the protection action of the power supply circuit due to the slow decrease of insulation in rainy or humid scenarios. The protection module executes the leakage protection of the power supply circuit based on the comparison results of the slowly changing voltage component and the target voltage threshold and the comparison results of the transient voltage component and the preset voltage threshold. This can not only act quickly when instantaneous fault leakage occurs, but also reasonably identify the gradual leakage caused by the environment, reduce non-fault power outages, and take into account both the continuity of energy storage system operation and leakage protection safety, thereby improving the environmental adaptability and operational reliability of the energy storage system.

[0069] Figure 2 A schematic diagram of the leakage current protection circuit provided in the second embodiment is shown below. Figure 2 As shown, Figure 2 Compared to the example Figure 1 The difference in the embodiments is that the protection module includes a first comparison unit, a second comparison unit, and a driving unit.

[0070] The first input terminal of the first comparison unit is connected to the gradually changing component output terminal of the component transmission module. The second input terminal of the first comparison unit is connected to the output terminal of the threshold setting module. The output terminal of the first comparison unit is connected to the first input terminal of the drive unit. The first comparison unit is used to output a first protection signal when the gradually changing voltage component is greater than the target voltage threshold.

[0071] The first input terminal of the second comparison unit is connected to the transient component output terminal of the component through the module. The voltage at the second input terminal of the second comparison unit is a preset voltage threshold. The output terminal of the second comparison unit is connected to the second input terminal of the drive unit. The second comparison unit is used to output a second protection signal when the transient voltage component is greater than the preset voltage threshold.

[0072] The drive unit is used to disconnect the power supply circuit when a first protection signal and / or a second protection signal are received.

[0073] In some embodiments, both the first protection signal and the second protection signal are high-level signals.

[0074] In some embodiments, the first comparison unit is configured to output a third protection signal when the slowly varying voltage component is less than or equal to a target voltage threshold. Exemplarily, the third protection signal is a low-level signal.

[0075] In some embodiments, the second comparison unit is configured to output a fourth protection signal when the transient voltage component is less than or equal to a preset voltage threshold. Exemplarily, the fourth protection signal is a low-level signal.

[0076] In some embodiments, the driving unit is used to drive the power supply circuit to turn on when it receives the third protection signal and the fourth protection signal.

[0077] exist Figure 2 In the illustrated embodiments, the target voltage threshold is represented by Vref_final, and the preset voltage threshold is represented by Vref_fixed. In some embodiments, Vref_fixed can be a pre-set fixed value. Vref_fixed does not change with humidity. In other embodiments, Vref_fixed can be determined based on multiple voltage thresholds that correspond one-to-one with multiple voltage threshold intervals. For example, Vref_fixed can be the average of multiple voltage thresholds. For instance, if the multiple voltage thresholds are 2V, 3V, and 4V, then Vref_fixed can be 3V.

[0078] In some embodiments, the first comparison unit may include a comparator U1, resistors R1, R2, and R3, capacitors C1 and C2. The component passing module's gradually changing component output is connected to the positive input of comparator U1 via resistor R1. The output of the threshold setting module is connected to the inverting input of comparator U1 via resistor R2. The inverting input of comparator U1 is also grounded via capacitor C1. The output of comparator U1 is connected to a preset voltage source providing voltage VCC via resistor R3. The output of comparator U1 is also grounded via capacitor C2. The output of comparator U1 is the output of the first comparison unit.

[0079] It should be noted that, unless otherwise specified, the resistors in the embodiments of this application refer to resistors with fixed resistance values.

[0080] It should be noted that the power supply voltage for the comparator and operational amplifier in the embodiments of this application is VCC.

[0081] In some embodiments, the second comparison unit may include a comparator U2 and a resistor R4. The transient component is connected to the positive input of the comparator U2 via the transient component output of the module. The voltage at the inverting input of the comparator U2 is a preset voltage threshold (Vref_fixed). The output of the comparator U2 is also connected to a preset voltage source for providing voltage VCC via resistor R4. The output of the comparator U2 is the output of the second comparison unit.

[0082] In some embodiments, the driving unit includes diode D1, diode D2, and a driving subunit. The anode of diode D1 is connected to the output terminal of the first comparator unit, and the cathode of diode D1 is connected to the first input terminal of the driving subunit. The anode of diode D2 is connected to the output terminal of the second comparator unit, and the cathode of diode D2 is connected to the second input terminal of the driving subunit. The output terminal of the driving subunit is connected to a power supply circuit. The driving subunit is used to disconnect the power supply circuit upon receiving a first protection signal and / or a second protection signal.

[0083] The drive subunit can be implemented in various ways. For example, taking a circuit breaker as an example of a switch in a power supply circuit, the drive subunit can include a thyristor. The cathodes of diodes D1 and D2 are both connected to the gate of the thyristor, the cathode of the thyristor is grounded, and the anode of the thyristor is connected to the trip coil in the circuit breaker. When the thyristor receives a first protection signal and / or a second protection signal, it drives the trip mechanism to operate, causing the auxiliary contacts of the circuit breaker to open and the power supply circuit to be disconnected. This application does not limit the implementation method of the drive subunit.

[0084] In the technical solution provided in this application embodiment, the first comparison unit compares the gradually changing voltage component with the target voltage threshold output by the threshold setting module in real time. When the gradually changing voltage component is greater than the target voltage threshold, it outputs a first protection signal, which can accurately identify progressive insulation abnormalities caused by factors such as changes in environmental humidity. The second comparison unit compares the transient voltage component with a preset voltage threshold. When the transient voltage component is greater than the preset voltage threshold, it outputs a second protection signal, which can quickly respond to transient leakage faults. The drive unit executes an action when it receives the first protection signal and / or the second protection signal, driving the power supply circuit to disconnect. This ensures reliable protection against real leakage faults and allows for reasonable judgment of progressive leakage based on environmental adaptation thresholds, avoiding false operation problems caused by single threshold protection. This enables the system to operate stably in complex and humid environments, effectively improving the accuracy and operational continuity of leakage protection in the energy storage system.

[0085] Figure 3 A schematic diagram of the leakage current protection circuit provided in the third embodiment is shown below. Figure 3 As shown, Figure 3 Compared to the example Figure 1 The difference in the embodiments is that the component passing module includes a slowly varying component passing unit and a transient component passing unit.

[0086] The gradually changing component is connected to the output of the leakage current detection module through the input terminal of the unit, and the gradually changing component is connected to the component input terminal of the protection module through the output terminal of the unit. The gradually changing component is used by the unit to pass the gradually changing voltage component in the leakage current detection voltage.

[0087] The transient component is connected to the output of the leakage current detection module through the input terminal of the unit, and the transient component is connected to the component input terminal of the protection module through the output terminal of the unit. The transient component is used by the unit to detect the transient voltage component in the leakage current detection voltage.

[0088] The output of the leakage current detection module is used to output the leakage current detection voltage, denoted by V_leak. For example, V_leak is positively correlated with the effective value of the main circuit leakage current.

[0089] In some embodiments, the gradually varying component passing unit includes a low-pass filter and a first voltage follower U3; the input of the low-pass filter is connected to the output of the leakage current detection module, the output of the low-pass filter is connected to the input of the first voltage follower U3, and the output of the first voltage follower U3 is connected to the component input of the protection module (i.e., the gradually varying component input, for example, ...). Figure 2 (The first input terminal of the first comparison unit in the embodiment).

[0090] In some embodiments, the low-pass filter includes a resistor R5 and a capacitor C3. The output of the leakage current detection module is connected to the input of a first voltage follower U3 via resistor R5. The input of the first voltage follower U3 is also grounded via capacitor C3. The output of the first voltage follower U3 is the output of the slowly changing component passing unit and is connected to the component input of the protection module. For example, in the low-pass filter, the resistance of resistor R5 is 1MΩ, the capacitance of capacitor C3 is 10μF, and the time constant is 10 seconds. The low-pass filter allows extremely slow changes to pass through. The voltage output of the low-pass filter can be represented by Vavg, reflecting the background value of the leakage current, such as the slow decrease in insulation due to rising humidity. Any sudden changes (such as electric shock) will be filtered out because the time constant is too large to respond in time.

[0091] The transient component is handled by a unit including a high-pass filter and a second voltage follower U4. The input of the high-pass filter is connected to the output of the leakage current detection module, and the output of the high-pass filter is connected to the input of the second voltage follower U4. The output of the second voltage follower U4 is connected to the component input of the protection module (i.e., the transient component input, for example, ...). Figure 2 (First input terminal of the second comparison unit in the embodiment).

[0092] In some embodiments, the high-pass filter includes a resistor R6 and a capacitor C4. The output of the leakage current detection module is connected to the input of the second voltage follower U4 via capacitor C4. The input of the second voltage follower U4 is also grounded via resistor R6. The output of the second voltage follower U4 is the output of the transient component passing unit and is connected to the component input of the protection module. For example, in the high-pass filter, the capacitance of capacitor C4 is 1μF, the resistance of resistor R6 is 15kΩ, and the cutoff frequency is 10.6Hz. The high-pass filter can block DC and slowly changing signals, allowing only abrupt changes to pass through. The voltage output of the high-pass filter can be represented by Vdiff. This allows spikes caused by electric shock to pass smoothly, while slowly changing signals caused by weather conditions are filtered out.

[0093] In the above embodiments, two different types of leakage signals can be distinguished using purely hardware methods.

[0094] In the technical solution provided in this application embodiment, the gradually changing component unit can filter and transmit the gradually changing voltage component in the leakage current detection voltage that changes slowly with environmental humidity and other factors, providing a stable progressive leakage current characteristic signal for subsequent protection judgment. The transient component unit can filter and transmit the transient voltage component in the leakage current detection voltage that changes abruptly, providing an accurate transient leakage current characteristic signal for subsequent protection judgment. In this way, by transmitting different types of voltage components through two independent units, the mutual interference between the gradually changing voltage component and the transient voltage component can be avoided, enabling the protection module to make independent judgments based on their respective thresholds. This can accurately respond to both gradually changing leakage current faults caused by humid environments and instantaneous leakage current faults, reducing the occurrence of false trips and effectively improving the accuracy and operational continuity of leakage current protection in energy storage systems.

[0095] Figure 4 This is a schematic diagram of the circuit structure of the threshold setting module provided in the first embodiment. The threshold setting module is used to output the target voltage threshold (Vref_final), as shown below. Figure 4 As shown, the threshold setting module includes a humidity detection unit and a threshold output unit; the input of the threshold output unit is connected to the humidity detection unit, and the output of the threshold output unit is connected to the threshold input of the protection module.

[0096] The humidity detection unit is used to detect the ambient humidity voltage; the threshold output unit is used to output a target voltage threshold (Vref_final) that matches the target voltage threshold range among multiple voltage threshold ranges in which the ambient humidity voltage is located.

[0097] In the technical solution provided in this application embodiment, the humidity detection unit detects the ambient humidity voltage in real time. The ambient humidity voltage can accurately reflect the current humidity level of the environment, providing a true and reliable environmental parameter for threshold adjustment. The threshold output unit matches and outputs the corresponding target voltage threshold based on the target voltage threshold range among multiple voltage threshold ranges corresponding to the ambient humidity voltage, so that the target voltage threshold can be adaptively adjusted with the ambient humidity. This can reduce the problem of power supply circuit erroneous disconnection caused by fixed thresholds under high humidity, rainy and other conditions. Thus, while ensuring reliable identification of real leakage faults, it reduces the impact of environmental factors on protection actions, making the leakage protection logic more in line with the actual operating conditions of complex outdoor environments, improving the rationality and accuracy of leakage protection of the energy storage system, and facilitating the continuous and stable operation of the power supply circuit in non-fault conditions, thereby improving the environmental adaptability of the energy storage system.

[0098] Figure 5 A schematic diagram of the circuit structure of the threshold setting module provided in the second embodiment is shown below. Figure 5 As shown, Figure 5 Compared to the example Figure 4The difference in the embodiments is that the humidity detection unit includes a humidity sampling subunit, a first rectifier subunit, and a first amplification subunit.

[0099] The input terminal of the first rectifier subunit is connected to the humidity sampling subunit, the output terminal of the first rectifier subunit is connected to the input terminal of the first amplification subunit, and the output terminal of the first amplification subunit is connected to the input terminal of the threshold output unit.

[0100] The humidity sampling subunit is used to output an alternating voltage of ambient humidity; the first rectifier subunit is used to rectify the alternating voltage of ambient humidity and output a rectified voltage of ambient humidity; the first amplification subunit is used to amplify the rectified voltage of ambient humidity to obtain an ambient humidity voltage.

[0101] The humidity sampling subunit includes a humidity-sensitive resistor R7 and a resistor R8. The first terminal of the humidity-sensitive resistor R7 is connected to the first terminal of the resistor R8, and the second terminal of the humidity-sensitive resistor R7 is grounded. The voltage across the second terminal of the resistor R8 is the AC drive voltage. This creates a voltage divider between the humidity-sensitive resistor R7 and the resistor R8, with the output voltage at the divider point being V_ac_hum. The amplitude of V_ac_hum varies with the ambient humidity; for example, the higher the humidity, the lower the amplitude (because the humidity-sensitive resistor becomes smaller).

[0102] The first rectifier subunit shown in this embodiment may include a half-wave rectifier subunit. In other embodiments of this application, the first rectifier subunit may include a full-wave rectifier subunit. The first rectifier subunit may include resistors R9, R10, and R11, operational amplifier U5, diode D3, and diode D4. The first terminal of resistor R9 is the input terminal of the first rectifier subunit and is connected to the voltage divider point of the humidity sampling subunit. The second terminal of resistor R9 is connected to the inverting input terminal of operational amplifier U5, and the non-inverting input terminal of operational amplifier U5 is grounded. The second terminal of resistor R9 is also connected to the anode of diode D3. The cathode of diode D3 is connected to the output terminal of operational amplifier U5, and the output terminal of operational amplifier U5 is also connected to the anode of diode D4. The cathode of diode D4 is the output terminal of the first rectifier subunit. The second terminal of resistor R9 is also connected to the cathode of diode D4 through resistor R10, and the cathode of diode D4 is grounded through resistor R11. The output voltage of the first rectifier subunit is V_raw.

[0103] In some embodiments, the first amplification subunit includes resistors R12, R13, and R14, a variable resistor R15, and an operational amplifier U6. A preset voltage source for the output voltage VCC is connected to the positive input terminal of the operational amplifier U6 via resistor R12. The first end of resistor R13 is the input terminal of the first amplification subunit and is also connected to the output terminal of the first rectifier subunit. The second end of resistor R13 is connected to the inverting input terminal of the operational amplifier U6. The positive input terminal of the operational amplifier U6 is also grounded via resistor R14, and the inverting input terminal of the operational amplifier U6 is also grounded via the variable resistor R15. The sliding end of the variable resistor R15 is connected to the output terminal of the operational amplifier U6, which is the output terminal of the first amplification subunit. The voltage output by the operational amplifier U6 is V_hum. For example, by adjusting the resistance value of the variable resistor R15, the amplification factor of V_raw by the first amplification subunit can be adjusted. For example, by adjusting the resistance of the sliding rheostat R15, V_hum is the minimum humidity voltage, for example, 1V, when the relative humidity (RH) is 50%, and V_hum is the maximum humidity voltage, for example, 3V, when the relative humidity is 80%.

[0104] Relative humidity is a physical quantity that represents the ratio of the water vapor content in the air to the maximum amount of water vapor that the air can hold at the current temperature, and is usually expressed as a percentage (%).

[0105] In the technical solution provided in this application embodiment, the humidity sampling subunit can output an alternating ambient humidity voltage that reflects changes in ambient humidity in real time, providing a raw signal for humidity detection. The first rectifier subunit rectifies the alternating ambient humidity voltage to avoid interference from negative voltage on subsequent threshold judgment. The first amplification subunit amplifies the rectified ambient humidity voltage to obtain an ambient humidity voltage that matches the amplitude of the subsequent circuit, ensuring that the signal amplitude meets the input requirements of the threshold output unit and improving the stability of signal transmission and recognition. Thus, through the hierarchical processing of rectification and amplification, the accuracy and anti-interference capability of the ambient humidity voltage can be effectively improved, enabling the threshold output unit to divide the corresponding voltage threshold range based on the accurate ambient humidity voltage and output the target voltage threshold. This allows the protection module to operate reliably in different humidity environments, reducing protection misjudgments caused by humidity detection signal distortion and improving the stability of the energy storage system in humid environments and the accuracy of leakage protection.

[0106] In some embodiments, the threshold output unit includes a first comparison subunit, a second comparison subunit, and a threshold output subunit.

[0107] The first input terminal of the first comparison subunit is connected to the output terminal of the humidity detection unit. The voltage at the second input terminal of the first comparison subunit is the first voltage threshold. The output terminal of the first comparison subunit is connected to the first input terminal of the threshold output subunit, and is used to output a first comparison signal between the ambient humidity voltage and the first voltage threshold.

[0108] The first input terminal of the second comparison subunit is connected to the output terminal of the humidity detection unit. The voltage at the second input terminal of the second comparison subunit is the second voltage threshold. The output terminal of the second comparison subunit is connected to the second input terminal of the threshold output subunit, and is used to output a second comparison signal between the ambient humidity voltage and the second voltage threshold.

[0109] The threshold output subunit is used to output a target voltage threshold based on a first comparison signal and a second comparison signal.

[0110] In some embodiments, the first comparator subunit includes resistors R16, R17, R18, R19, and R20, capacitors C5 and C6, comparator U7, and transistor Q1. A preset voltage source for the output voltage VCC is connected to the inverting input of comparator U7 via resistor R16. The inverting input of comparator U7 is also grounded via resistor R17. The non-inverting input of comparator U7 is the input of the first comparator subunit, and the voltage input to the non-inverting input of comparator U7 is V_hum. The output of comparator U7 is connected to the preset voltage source for the output voltage VCC via resistor R18. The output of comparator U7 is also grounded via capacitor C5. The output of comparator U7 outputs the signal OUT_H. The output of comparator U7 is connected to the base of transistor Q1 via resistor R19. The emitter of transistor Q1 is grounded. The collector of transistor Q1 is connected to the preset voltage source for the output voltage VCC via resistor R20. The collector of transistor Q1 is also grounded via capacitor C6. The collector of transistor Q1 is the output of the first comparator subunit. For example, the voltage at the inverting input of comparator U7 is the maximum humidity voltage, for example, 3V.

[0111] In some embodiments, the second comparator subunit includes resistors R21, R22, R23, and R24, capacitor C6, and comparator U8. A preset voltage source for the output voltage VCC is connected to the inverting input of comparator U8 via resistor R21. The inverting input of comparator U8 is also grounded via resistor R22. The non-inverting input of comparator U8 is the input of the second comparator subunit, and the voltage input to the non-inverting input of comparator U8 is V_hum. The output of comparator U8 is connected to VCC via resistor R23. The output of comparator U8 is also grounded via capacitor C6. The output of comparator U8 outputs a signal OUT_L. The output of comparator U8 is connected to the first terminal of resistor R24, and the second terminal of resistor R24 ​​is the output of the second comparator subunit. For example, the voltage at the inverting input of comparator U8 is the minimum humidity voltage, for example, 1V.

[0112] In some embodiments, the threshold output subunit includes an analog switch, a resistor R25, and a third voltage follower U9. The analog switch includes pins VDD, COM, A, B, CH1, CH2, and CH3. The analog switch is used to output one of voltages Y1, Y2, and Y3 through pin COM based on the levels received at pins A and B, and based on voltages Y1 at pin CH1, Y2 at pin CH2, and Y3 at pin CH3. Exemplarily, the voltage output at pin COM is a target voltage value. Exemplarily, the values ​​of voltages Y1, Y2, and Y3 are different; exemplarily, voltages Y1, Y2, and Y3 can be selected according to requirements. For example, voltage Y1 is 2V, voltage Y2 is 3V, and voltage Y3 is 4V. Exemplarily, 2V corresponds to a 30mA leakage threshold, 3V corresponds to a 45mA leakage threshold, and 4V corresponds to a 60mA leakage threshold, respectively applicable to balcony photovoltaic systems in low-humidity, medium-humidity, and high-humidity environments.

[0113] For example, the values ​​of voltages Y1, Y2, and Y3 can be determined based on V_leak (i.e., the leakage detection voltage output by the leakage detection module). For instance, the leakage detection voltage V_leak is approximately 2.1V at 30mA, so voltage Y1 can be set slightly lower to allow for a margin, hence voltage Y1 is 2V.

[0114] For example, when V_hum < 1.0V (humidity < 50%), the level of pin A is 0 and the level of pin B is 1; when 1.0V ≤ V_hum ≤ 3.0V (50%-80%), the level of pin A is 1 and the level of pin B is 1; when V_hum > 3.0V (humidity > 80%), the level of pin A is 1 and the level of pin B is 0.

[0115] In some embodiments, pin COM can also be connected to the first end of resistor R25, the second end of resistor R25 is connected to the input of the third voltage follower U9, and the output of the third voltage follower U9 is the output of the threshold output subunit, used to output the target voltage threshold Vref_final.

[0116] Table 1 illustrates the relationship between the ambient relative humidity range, V_hum, and the voltage levels of pins A and B.

[0117] Table 1

[0118]

[0119] Table 2 illustrates the relationship between the ambient relative humidity range, the voltage levels of pins A and B, the selected voltage, and Vref_final.

[0120] Table 2

[0121]

[0122] In this way, Vref_final is a threshold voltage that is automatically adjusted according to humidity. The higher the humidity, the more lenient the threshold becomes, thus avoiding false alarms on rainy days.

[0123] In the technical solution provided in this application embodiment, the first comparison subunit compares the ambient humidity voltage with a first voltage threshold and outputs a first comparison signal; the second comparison subunit compares the ambient humidity voltage with a second voltage threshold and outputs a second comparison signal. The two subunits work together to accurately define the voltage threshold range corresponding to the ambient humidity, achieving graded discrimination of ambient humidity. The threshold output subunit, based on the two comparison signals, matches and outputs the target voltage threshold for the corresponding range, enabling the protection judgment benchmark to adaptively adjust with changes in ambient humidity. This avoids malfunctions caused by misjudging slowly changing voltage components under high humidity conditions with a fixed threshold, while ensuring fault detection sensitivity for transient voltage components. It balances the reliability of leakage protection with the continuity of system operation, effectively improving the operational stability and protection accuracy of the energy storage system under complex and humid conditions.

[0124] Figure 6 A circuit structure diagram of the leakage current detection module provided in the first embodiment is shown below. Figure 6 As shown, the leakage current detection module includes a zero-sequence current transformer (CT), a sampling resistor (Rs), and a leakage current output unit.

[0125] The primary side of the zero-sequence current transformer (CT) passes through the power supply circuit, and the secondary side of the zero-sequence current transformer (CT) is connected in parallel with a sampling resistor Rs. The secondary side of the zero-sequence current transformer (CT) is also connected to the input terminal of the leakage current output unit, and the output terminal of the leakage current output unit is connected to the input terminal of the component current through module.

[0126] Zero-sequence current transformers (CTs) are used to sense the leakage current in the power supply circuit and output a leakage AC voltage that matches the leakage current. The leakage output unit is used to convert the leakage AC voltage into a leakage detection voltage.

[0127] The first terminal of the secondary side of the zero-sequence current transformer (CT) is connected to the first terminal of the sampling resistor Rs, the second terminal of the sampling resistor Rs is connected to the second terminal of the secondary side of the zero-sequence current transformer (CT), the first terminal of the secondary side of the zero-sequence current transformer (CT) is also connected to the input terminal of the leakage current output unit, and the second terminal of the secondary side of the zero-sequence current transformer (CT) is also grounded.

[0128] Zero-sequence current transformers (CTs) are single-turn through-core devices used in power systems to monitor zero-sequence current. They are core components of power protection devices, primarily used for ground fault detection, leakage current protection, and insulation monitoring. The CT triggers protection action by detecting the vector sum of the three-phase currents (zero-sequence current). When no leakage occurs in the power supply circuit, the vector sum of the three-phase currents is 0, the leakage current induced by the CT is 0, and the leakage AC voltage (V_ac_leak) input to the secondary side leakage current output unit of the CT is 0. When leakage occurs in the power supply circuit, the vector sum of the three-phase currents is not 0, the leakage current induced by the CT is not 0, and the leakage AC voltage (V_ac_leak) input to the secondary side leakage current output unit of the CT is not 0.

[0129] In the technical solution provided in this application embodiment, the primary side of the zero-sequence current transformer passes through the power supply circuit, enabling it to sense the leakage current of the power supply circuit in real time. The sampling resistor is connected in parallel to the secondary side of the zero-sequence current transformer, which can linearly convert the sensed leakage current into a leakage AC voltage. The leakage output unit converts the leakage AC voltage into a leakage detection voltage, adapts it to the input requirements of the subsequent component passing module, and thus effectively extracts the leakage characteristics of the power supply circuit. It completely preserves the slowly changing voltage component and the transient voltage component in the leakage detection voltage, providing a reliable signal basis for subsequently distinguishing between gradual leakage caused by the environment and transient fault-type leakage, improving the detection accuracy and response reliability of leakage protection, and ensuring the safe and stable operation of the power supply circuit of the energy storage system.

[0130] Figure 7 A circuit structure diagram of the leakage current detection module provided in the second embodiment is shown below. Figure 7 As shown, Figure 7 Compared to the example Figure 6 The difference in the embodiments is that the leakage output unit includes a second amplification subunit, a second rectifier subunit, and a filter subunit.

[0131] The input terminal of the second amplification subunit is connected to the secondary side of the zero-sequence current transformer, the output terminal of the second amplification subunit is connected to the input terminal of the second rectifier subunit, the output terminal of the second rectifier subunit is connected to the input terminal of the filter subunit, and the output terminal of the filter subunit is connected to the input terminal of the component pass module.

[0132] The second amplification subunit is used to amplify the leakage AC voltage to obtain the leakage AC amplified voltage; the second rectifier subunit is used to rectify the leakage AC amplified voltage to obtain the leakage rectified voltage; and the filter subunit is used to filter the leakage rectified voltage to obtain the leakage detection voltage.

[0133] For example, the second rectifier subunit may include a full-wave rectifier subunit. For example, the filter subunit may include a second-order filter subunit.

[0134] In some embodiments, the second amplification subunit includes resistors R26, R27, R28, and R29, and operational amplifier U10. The first terminal of the secondary side of the zero-sequence current transformer (CT) outputs a leakage AC voltage V_ac_leak. The first terminal of the secondary side of the zero-sequence current transformer (CT) is connected to the positive input terminal of operational amplifier U10 through resistor R27. The inverting input terminal of operational amplifier U10 is grounded through resistor R26. Resistor R28 is connected between the inverting input terminal and the output terminal of operational amplifier U10. The positive input terminal of operational amplifier U10 is also grounded through resistor R29. The output terminal of operational amplifier U10 is the output terminal of the second amplification subunit, outputting a leakage AC amplified voltage (represented by V_ac_amp).

[0135] The second rectifier subunit includes resistors R30, R31, R32, R33, and R34, diodes D5 and D6, operational amplifier U11, and operational amplifier U12. The first terminal of resistor R30 is the input terminal of the second rectifier subunit and is connected to the output terminal of the second operational amplifier subunit. The second terminal of resistor R30 is connected to the first terminal of resistor R31. The second terminal of resistor R31 is connected to the anode of diode D6, and the cathode of diode D6 is connected to the output terminal of operational amplifier U11. The second terminal of resistor R31 is connected to the first terminal of resistor R32. The second terminal of resistor R30 is also connected to the cathode of diode D5, and the anode of diode D5 is connected to the output terminal of operational amplifier U11. The second terminal of resistor R30 is also connected to the inverting input terminal of operational amplifier U11. The positive input terminal of operational amplifier U11 is grounded. The second terminal of resistor R32 is connected to the first terminal of resistor R33. The second terminal of resistor R32 is also connected to the inverting input terminal of operational amplifier U12. The positive input terminal of operational amplifier U12 is grounded. The output terminal of operational amplifier U12 is connected to the second terminal of resistor R33. The first terminal of resistor R34 is connected to the first terminal of resistor R30. The second terminal of resistor R34 is connected to the second terminal of resistor R32. The output terminal of operational amplifier U12 is the output terminal of the second rectifier subunit. The output terminal of the second rectifier subunit outputs a leakage rectified voltage (represented by V_rect).

[0136] In some embodiments, the filter subunit includes resistors R35, R36, R37, and R38, capacitors C7 and C8, and operational amplifier U13. The first terminal of resistor R35 is the input terminal of the filter subunit and is connected to the output terminal of the second rectifier subunit. The second terminal of resistor R35 is connected to the first terminal of resistor R36, and the second terminal of resistor R36 is connected to the non-inverting input terminal of operational amplifier U13. The first terminal of capacitor C8 is connected to the non-inverting input terminal of operational amplifier U13, and the second terminal of capacitor C8 is grounded. The first terminal of resistor R37 is connected to the inverting input terminal of operational amplifier U13, and the second terminal of resistor R37 is grounded. The first terminal of resistor R38 is connected to the inverting input terminal of operational amplifier U13, and the second terminal of resistor R38 is connected to the output terminal of operational amplifier U13. The first terminal of capacitor C7 is connected to the first terminal of resistor R36, and the second terminal of capacitor C7 is connected to the output terminal of operational amplifier U13. The output terminal of operational amplifier U13 is the output terminal of the filter subunit, and the output terminal of the filter subunit outputs a leakage current detection voltage (represented by V_leak).

[0137] In the technical solution provided in this application embodiment, the second amplification subunit amplifies the leakage AC voltage to obtain a leakage AC amplified voltage with an amplitude that meets the input requirements of the subsequent circuit, effectively amplifying the weak leakage current signal and improving the signal's identifiability. The second rectifier subunit rectifies the leakage AC amplified voltage, converting the AC signal into a leakage rectified voltage and eliminating the interference of negative voltage on subsequent judgments. The filter subunit filters the leakage rectified voltage, eliminating high-frequency noise and spurious waves to obtain a smooth and stable leakage detection voltage, providing an accurate and pure characteristic signal for the component passing module. Thus, through the step-by-step amplification, rectification, and filtering process, noise interference during the detection process can be effectively suppressed, ensuring the accuracy and stability of the leakage detection voltage. This ensures that the component passing module can accurately separate the slowly varying voltage component and the transient voltage component, providing a solid and reliable signal foundation for accurate leakage protection judgment.

[0138] Figure 8 A circuit structure diagram of an energy storage system is provided for some embodiments, such as Figure 8 As shown, the energy storage system includes a power supply circuit and a leakage protection circuit as provided in any of the foregoing embodiments, connected to the power supply circuit.

[0139] In some embodiments, the energy storage system may further include photovoltaic modules and a load, with a power supply circuit connected between the photovoltaic modules and the load.

[0140] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0141] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A leakage current protection circuit, characterized in that, The leakage protection circuit includes: a leakage detection module, a component transmission module, a threshold setting module, and a protection module; the threshold setting module includes a humidity detection unit and a threshold output unit; the input terminal of the leakage detection module is connected to the power supply circuit, the output terminal of the leakage detection module is connected to the input terminal of the component transmission module, the output terminal of the component transmission module is connected to the component input terminal of the protection module, the threshold input terminal of the protection module is connected to the output terminal of the threshold output unit, the output terminal of the protection module is connected to the power supply circuit, the input terminal of the threshold output unit is connected to the humidity detection unit, and the threshold output unit includes a first comparison subunit, a second comparison subunit, and a threshold output subunit; The leakage current detection module is used to output the leakage current detection voltage of the power supply circuit; The component is passed through a module for passing the slowly varying voltage component and the transient voltage component in the leakage current detection voltage; The humidity detection unit is used to detect ambient humidity voltage; The first input terminal of the first comparison subunit is connected to the output terminal of the humidity detection unit, the voltage of the second input terminal of the first comparison subunit is a first voltage threshold, and the output terminal of the first comparison subunit is connected to the first input terminal of the threshold output subunit, for outputting a first comparison signal between the ambient humidity voltage and the first voltage threshold. The first input terminal of the second comparison subunit is connected to the output terminal of the humidity detection unit, the voltage of the second input terminal of the second comparison subunit is the second voltage threshold, and the output terminal of the second comparison subunit is connected to the second input terminal of the threshold output subunit, for outputting a second comparison signal between the ambient humidity voltage and the second voltage threshold. The threshold output subunit is used to output a target voltage threshold based on the first comparison signal and the second comparison signal; The protection module is used to drive the power supply circuit to disconnect when the slowly varying voltage component is greater than the target voltage threshold, and / or when the transient voltage component is greater than the preset voltage threshold.

2. The leakage current protection circuit according to claim 1, characterized in that, The protection module includes a first comparison unit, a second comparison unit, and a driving unit; The first input terminal of the first comparison unit is connected to the gradually changing component output terminal of the component passing module, the second input terminal of the first comparison unit is connected to the output terminal of the threshold setting module, and the output terminal of the first comparison unit is connected to the first input terminal of the driving unit, for outputting a first protection signal when the gradually changing voltage component is greater than the target voltage threshold; The first input terminal of the second comparison unit is connected to the transient component output terminal of the component passing module, the voltage of the second input terminal of the second comparison unit is the preset voltage threshold, and the output terminal of the second comparison unit is connected to the second input terminal of the drive unit, for outputting a second protection signal when the transient voltage component is greater than the preset voltage threshold; The driving unit is used to drive the power supply circuit to disconnect when it receives the first protection signal and / or the second protection signal.

3. The leakage protection circuit according to claim 1 or 2, characterized in that, The component passing module includes a slowly varying component passing unit and a transient component passing unit; The gradually changing component is connected to the output of the leakage current detection module through the input terminal of the unit, and the gradually changing component is connected to the component input terminal of the protection module through the output terminal of the unit, for use as the gradually changing voltage component in the leakage current detection voltage; The transient component is connected to the output of the leakage current detection module through the input terminal of the unit, and the transient component is connected to the component input terminal of the protection module through the output terminal of the unit, for use as the transient voltage component in the leakage current detection voltage.

4. The leakage protection circuit according to claim 3, characterized in that, The gradually changing component passing unit includes a low-pass filter and a first voltage follower; the input terminal of the low-pass filter is connected to the output terminal of the leakage current detection module, the output terminal of the low-pass filter is connected to the input terminal of the first voltage follower, and the output terminal of the first voltage follower is connected to the component input terminal of the protection module. The transient component passing unit includes a high-pass filter and a second voltage follower; the input of the high-pass filter is connected to the output of the leakage current detection module, the output of the high-pass filter is connected to the input of the second voltage follower, and the output of the second voltage follower is connected to the component input of the protection module.

5. The leakage protection circuit according to claim 1 or 2, characterized in that, The humidity detection unit includes a humidity sampling subunit, a first rectifier subunit, and a first amplification subunit; the input terminal of the first rectifier subunit is connected to the humidity sampling subunit, the output terminal of the first rectifier subunit is connected to the input terminal of the first amplification subunit, and the output terminal of the first amplification subunit is connected to the input terminal of the threshold output unit. The humidity sampling subunit is used to output an alternating voltage for ambient humidity. The first rectifier subunit is used to rectify the ambient humidity alternating voltage and output an ambient humidity rectified voltage; The first amplification subunit is used to amplify the rectified voltage of the ambient humidity to obtain the ambient humidity voltage.

6. The leakage protection circuit according to claim 1 or 2, characterized in that, The leakage current detection module includes a zero-sequence current transformer, a sampling resistor, and a leakage current output unit. The primary side of the zero-sequence current transformer passes through the power supply circuit, the secondary side of the zero-sequence current transformer is connected in parallel with the sampling resistor, the secondary side of the zero-sequence current transformer is also connected to the input terminal of the leakage current output unit, and the output terminal of the leakage current output unit is connected to the input terminal of the component current passing module. The zero-sequence current transformer is used to sense the leakage current of the power supply circuit and output a leakage AC voltage that is compatible with the leakage current. The leakage current output unit is used to convert the leakage current AC voltage into the leakage current detection voltage.

7. The leakage protection circuit according to claim 6, characterized in that, The leakage current output unit includes a second amplification subunit, a second rectification subunit, and a filtering subunit; the input terminal of the second amplification subunit is connected to the secondary side of the zero-sequence current transformer, the output terminal of the second amplification subunit is connected to the input terminal of the second rectification subunit, the output terminal of the second rectification subunit is connected to the input terminal of the filtering subunit, and the output terminal of the filtering subunit is connected to the input terminal of the component passing module. The second amplification subunit is used to amplify the leakage AC voltage to obtain a leakage AC amplified voltage; The second rectifier subunit is used to rectify the leakage AC amplified voltage to obtain the leakage rectified voltage; The filtering subunit is used to filter the leakage current rectified voltage to obtain the leakage current detection voltage.

8. An energy storage system, characterized in that, The energy storage system includes a power supply circuit and a leakage protection circuit as described in any one of claims 1-7 connected to the power supply circuit.

Images