Transient current suppression device and dc microgrid system

Abstract

The utility model relates to a kind of transient current suppression device and direct current microgrid system, it is characterized in that, transient current suppression device includes: current suppression main circuit, including pre-charge path and bypass path, configured to selectively connect input end and output end through pre-charge path or bypass path;Input end voltage sampling circuit, configured to sample input voltage;Output end voltage sampling circuit, configured to sample output voltage;Auxiliary power supply, configured to power using the voltage of at least one of input end and output end;And MCU, connected to current suppression main circuit, auxiliary power supply, input end voltage sampling circuit and output end voltage sampling circuit. According to the utility model embodiment, it can satisfy to realize the current suppression of load direction and the direct bypass control of opposite direction, can execute transient impact current suppression, realizes bidirectional current suppression.

Description

Technical Field

[0001] This utility model relates to the field of DC microgrids, and more specifically, to a transient current suppression device and a DC microgrid system. Background Technology

[0002] With the development of DC microgrid power distribution technology, the power supply has changed from traditional transformers to power electronic converters, and the protection speed of power distribution products has also become faster. Therefore, the transient inrush current caused by capacitive load switching in the system is prone to cause life problems of converters and malfunctions of power distribution products, which affects the reliability and stability of the system.

[0003] In the scheme using a converter paired with a mechanical circuit breaker, the converter withstands the transient inrush current when the load is connected. The mechanical circuit breaker's protection speed is slow and it may malfunction, thus sacrificing the converter's lifespan and the selectivity of the system's distribution protection. In the scheme using a converter paired with a solid-state circuit breaker, a unidirectional transient current suppression device is configured; however, the unidirectional topology cannot be configured in applications with generation-consuming loads (BESS, VTG piles, etc.).

[0004] Therefore, a bidirectional transient current suppression scheme that can be connected to generating and consuming loads is needed. Utility Model Content

[0005] This invention provides a transient current suppression device, characterized in that it comprises: a current suppression main circuit connected between an input terminal and an output terminal, including a pre-charge path and a bypass path, configured to selectively connect the input terminal and the output terminal via the pre-charge path or the bypass path; an input voltage sampling circuit connected to the positive and negative terminals of the input terminal, configured to sample the input voltage; an output voltage sampling circuit connected to the positive and negative terminals of the output terminal, configured to sample the output voltage; an auxiliary power supply connected to the input terminal and the output terminal, configured to be powered by the voltage of at least one of the input terminal and the output terminal; and a microcontroller unit (MCU) connected to the current suppression main circuit, the auxiliary power supply, the input voltage sampling circuit, and the output voltage sampling circuit.

[0006] In one example, the input voltage sampling circuit includes: a first path connected between the positive and negative terminals of the input, comprising a second resistor, a third resistor, and a third switch connected in series; and a second path connected between the positive and negative terminals of the input, comprising a fourth resistor, a fifth resistor, and a fourth switch connected in series, wherein the resistance ratio between the second and third resistors is equal to the resistance ratio between the fourth and fifth resistors, and the resistance values ​​of the second, third, fourth, and fifth resistors are different.

[0007] In one example, the output voltage sampling circuit includes a sixth resistor and a seventh resistor connected in series.

[0008] In one example, the pre-charge path, connected between the input and the output, includes a first switch and a first resistor connected in series; and the bypass path, connected between the input and the output, includes a second switch, wherein the resistance value of the first resistor is set to control the magnitude of the transient current.

[0009] In one example, when the output voltage reaches the startup voltage, the second switch is closed while the first switch remains open.

[0010] In one example, when a voltage is detected at the input terminal, the first switch is closed and the second switch remains open. When the voltage difference between the input and output terminals is less than a predetermined threshold, the second switch is closed, and after a predetermined time period, the first switch is opened.

[0011] In one example, the precharge timing is based on the control timing of the load connected to the output, and the precharge timing includes the time period during which the first switch is closed and a predetermined time period.

[0012] In one example, the MCU is configured to: detect the voltage at a first node between the second and third resistors when the third switch is closed and the fourth switch is open; detect the voltage at a second node between the fourth and fifth resistors when the third switch is open and the fourth switch is closed; compare the voltage at the first node with the voltage at the second node; and determine, based on the comparison, whether the voltage at the input terminal is a false voltage.

[0013] In one example, the MCU is also configured to keep the first and second switches open when it is determined that the voltage at the input is a false voltage.

[0014] In one example, the MCU is also configured to: detect the voltage at a third node between the sixth and seventh resistors; determine the rate of rise of the voltage at the third node; compare the rate of rise with a predetermined rate threshold; and, based on the comparison, determine whether a power distribution fault exists.

[0015] In one example, the MCU is also configured to disconnect the first and second switches when a power distribution fault is detected.

[0016] According to an embodiment of the present invention, a DC microgrid system is also provided, including any of the transient current suppression devices described above.

[0017] Therefore, according to the embodiments of this utility model, power can be drawn from at least one of the input and output terminals to achieve current suppression in the load direction and direct bypass control in the opposite direction, and to perform transient impact current suppression on the generation and consumption type load branch, thus realizing bidirectional current suppression. Attached Figure Description

[0018] The above and other aspects, features, and advantages of specific embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 This is a schematic block diagram illustrating a transient current suppression device according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic circuit diagram showing the specific structure of the transient current suppression device according to an embodiment of the present invention;

[0021] Figure 3 This illustrates the operation of a bidirectional transient current suppression device in the event of grid startup according to an embodiment of the present invention;

[0022] Figure 4 This illustrates the operation of the bidirectional transient current suppression device during BESS startup according to an embodiment of the present invention; and

[0023] Figure 5 A schematic diagram of a transient current suppression device according to an embodiment of the present invention for detecting false voltage is shown. Detailed Implementation

[0024] Before proceeding with the detailed description below, it may be advantageous to define certain words and phrases used throughout this invention. The terms “comprising” and “including” and their derivatives mean, but are not limited to, any of the following. The term “controller” or “control unit” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or a combination of hardware and software and / or firmware. For example, a controller may include, for instance, an application-specific integrated circuit (ASIC), a general-purpose or special-purpose central processing unit (CPU), a digital signal processor (DSP), and programmable logic devices such as a field-programmable gate array (FPGA). A controller may be manufactured as a single printed circuit board (PCB) or distributed across several interconnected PCBs. A controller may include other processing circuitry; for example, a controller may include two processing circuits such as an FPGA and a CPU interconnected on a PCB. The functionality associated with any particular controller may be centralized or distributed, either local or remote. The phrase “at least one,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and perhaps only one item from the list is required. For example, "at least one of A, B, and C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C. Furthermore, in the description of this utility model, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance or order. In embodiments of this disclosure, unless otherwise expressly stated, "connection" does not necessarily mean "direct connection" or "direct contact," but only requires electrical connection.

[0025] Definitions of other specific words and phrases are provided throughout this invention. Those skilled in the art will understand that, in many, if not most, cases, such definitions apply to the prior and future use of the words and phrases thus defined.

[0026] The various embodiments of the present invention described below with reference to the accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of the present invention in any way. Those skilled in the art will understand that the principles of the present invention can be implemented in any suitably arranged system or device. In some cases, the actions described in the present invention can be performed in different orders and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific order or sequential sequence shown to achieve the desired result. In certain embodiments, multitasking and parallel processing may be advantageous.

[0027] The text and accompanying drawings are provided by way of example only to aid in understanding the present invention. They should not be construed as limiting the scope of the appended claims in any way. Although certain embodiments and examples have been provided, it will be clear to those skilled in the art, based on the content of the present invention, that changes can be made to the illustrated embodiments and examples without departing from the scope of the present invention.

[0028] Figure 1 This is a schematic block diagram showing a transient current suppression device 100 according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the transient current suppression device 100 may include: a current suppression main circuit 101 connected between the input and output terminals, including a pre-charge path and a bypass path, configured to selectively connect the input and output terminals via either the pre-charge path or the bypass path; an input voltage sampling circuit 102 connected to the positive terminal P1 and the negative terminal N1 of the input terminal, configured to sample the input voltage; an output voltage sampling circuit 103 connected to the positive terminal P2 and the negative terminal N2 of the output terminal, configured to sample the output voltage; an auxiliary power supply 104 connected to the input and output terminals, configured to be powered by the voltage of at least one of the input and output terminals; and a microcontroller unit (MCU) 105 connected to the current suppression main circuit, the auxiliary power supply, the input voltage sampling circuit, and the output voltage sampling circuit.

[0030] In addition, the input terminal may include a positive terminal P1 and a negative terminal N1, which are connected to the positive and negative lines of the DC bus, respectively, and the output terminal may include a positive terminal P2 and a negative terminal N2, which are connected to a converter (not shown) or a load, etc.

[0031] In the description of the embodiments of this utility model, the side facing the DC bus is called the input terminal, and the side away from the DC bus and connected to the converter is called the output terminal.

[0032] Therefore, according to the embodiments of this utility model, power can be drawn from at least one of the input and output terminals to achieve current suppression in the load direction and direct bypass control in the opposite direction, and to perform transient impact current suppression on the generation and consumption type load branch, thus realizing bidirectional current suppression.

[0033] Figure 2 This is a schematic circuit diagram showing the specific structure of the transient current suppression device according to an embodiment of the present invention.

[0034] like Figure 2As shown, the pre-charge path of the current suppression main circuit 101 can be connected between the input and output terminals, including a first switch K1 and a first resistor R1 connected in series, and the bypass path of the current suppression main circuit 101 can be connected between the input and output terminals, including a second switch K2, wherein the resistance value of the first resistor R1 is set to control the magnitude of the transient current.

[0035] The bypass path can be connected in parallel with the pre-charge path.

[0036] like Figure 2 As shown, the input voltage sampling circuit 102 may include: a first path connected between the positive terminal P1 and the negative terminal N1 of the input, including a second resistor R2, a third resistor R3, and a third switch K3 connected in series; and a second path connected between the positive terminal P1 and the negative terminal N1 of the input, including a fourth resistor R4, a fifth resistor R5, and a fourth switch K4 connected in series. The resistance ratio between the second resistor R2 and the third resistor R3 is equal to the resistance ratio between the fourth resistor R4 and the fifth resistor R5, and the resistance values ​​of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 are different.

[0037] In other words, R2 / R3 = R4 / R5, so that the voltage division ratio of the first path and the second path is the same. For the resistance values ​​of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5, it is acceptable as long as R2 equals R4 while R3 is not equal to R5, or R3 equals R5 while R2 is not equal to R4.

[0038] like Figure 2 As shown, the output voltage sampling circuit 103 may include a sixth resistor R6 and a seventh resistor R7 connected in series.

[0039] The auxiliary power supply 104 can draw power from the input and output terminals through diodes D1 and D2, respectively.

[0040] From here on, refer to Figures 3 to 5 The operation of the bidirectional transient current suppression device according to an embodiment of the present invention is described in detail.

[0041] First Embodiment

[0042] Figure 3 The operation of the bidirectional transient current suppression device in the event of grid startup, according to an embodiment of the present invention, is shown.

[0043] In addition to AC power grids, Figure 3An energy storage subsystem and a charging pile subsystem are also shown; however, those skilled in the art will understand that the transient current suppression device according to the embodiments of the present invention can be applied to other scenarios, such as photovoltaic subsystems.

[0044] In addition, for the sake of brevity and ease of description, Figure 3 Transient current suppression devices 100-1, 100-2, and 100-3 are shown only in part of the main current suppression circuit, while other components are omitted. Transient current suppression devices 100-1, 100-2, and 100-3 are connected to the DC bus via circuit breakers.

[0045] refer to Figure 3 When the AC-CDC converter is functioning normally and the power grid supply is normal, the AC-CDC converter starts to build up the bus voltage. When the transient current suppression device 100-1 detects that the voltage at the output terminal has reached the start-up voltage, the second switch K2 is closed to connect the circuit. At this time, the second switch K1 remains open.

[0046] The startup voltage can be pre-configured and is adjustable.

[0047] For transient current suppression devices 100-2 and 100-3, when they detect voltage at the input terminal, the first switch K1 is closed, and the second switch K2 remains open. At this time, the pre-charging path of transient current suppression devices 100-2 and 100-3 is activated, entering the pre-charging stage. The pre-charging stage can last for Δt1. By setting the resistance value of the corresponding first resistor R1, the current flowing to the energy storage subsystem and the charging pile subsystem can be controlled within a suitable range, thereby suppressing transient inrush current.

[0048] In one example, after a pre-charging period Δt1, transient current suppression devices 100-2 and 100-3 can determine whether the voltage difference between the input and output terminals is less than a predetermined threshold. When transient current suppression devices 100-2 and 100-3 detect that the voltage difference between the input and output terminals is less than the predetermined threshold, the second switch K2 is closed to activate the bypass path. After a predetermined period Δt2, the first switch K1 is opened.

[0049] After a predetermined time period Δt2, K1 is disconnected to ensure that K2 can be effectively closed. After the second switch K2 is closed, the first switch K1 is disconnected, so that if the second switch K2 is abnormally disconnected during normal operation, the current suppression main circuit is broken, ensuring safety.

[0050] On the other hand, when transient current suppression devices 100-2 and 100-3 detect that the voltage difference between the input and output terminals is not less than a predetermined threshold, pre-charging can continue. Furthermore, after another pre-charging period Δt1, transient current suppression devices 100-2 and 100-3 can again determine whether the voltage difference between the input and output terminals is less than the predetermined threshold.

[0051] The predetermined threshold is associated with the voltage difference between the input and output voltages, and can be pre-configured and adjusted according to actual conditions. In one example, the predetermined threshold can be set by software and can be adjustable according to the load.

[0052] If the voltage difference is less than a predetermined threshold, the second switch K2 is closed to connect the bypass path. After a predetermined time period Δt2, the first switch K1 is opened, and the transient current suppression devices 100-2 and 100-3 operate normally.

[0053] If the voltage difference is not less than a predetermined threshold, the transient current suppression device 100-2 and the transient current suppression device 100-3 will disconnect the first switch K1 and the second switch K2 and execute a fault alarm.

[0054] exist Figure 3 In the illustrated scenario, transient current suppression device 100-1 performs energy transfer, while transient current suppression devices 100-2 and 100-3 perform transient current suppression. Therefore, transient current suppression device 100 can both suppress current in the reverse direction of the load and achieve direct bypass control in the opposite direction.

[0055] Through a microcontroller unit (MCU) (such as Figure 1 and Figure 2 (As shown in the figure) to control the opening and closing of the first switch K1 and the second switch K2.

[0056] The first switch K1 and the second switch K2 can be implemented by mechanical contacts or power electronic devices, ensuring the safety of the transient current suppression device 100 (100-1, 100-2, 100-3) when it fails during normal operation and when it is not working.

[0057] Furthermore, for transient current suppression devices 100-2 and 100-3 connected to the generation-consumption load branch, their pre-charge timing includes: the time period during which the first switch is closed, i.e., the pre-charge phase time period Δt1; and the predetermined time period Δt2. The pre-charge timing is based on the control timing of the load connected to the output terminal.

[0058] The values ​​of Δt1 and Δt2 can be pre-configured according to the actual situation and are adjustable.

[0059] The pre-charge timing of the transient current suppression device and the control timing of the load module can be coordinated through timing adjustments. This means that by pre-setting the timing, the load module can be ensured to start up only after the transient current suppression device has been bypassed. Alternatively, the timing coordination between the transient current suppression device and the load module can be achieved by sending a signal notification from the MCU 105 to the connected DC-DC converter via DIDO or communication (RS485, etc.).

[0060] Second Embodiment

[0061] Figure 4 This illustrates the operation of the bidirectional transient current suppression device during BESS startup according to an embodiment of the present invention.

[0062] and Figure 3 Similarly, in addition to AC power grids, Figure 4 An energy storage subsystem and a charging pile subsystem are also shown; however, those skilled in the art will understand that the transient current suppression device according to the embodiments of the present invention can be applied to other scenarios, such as photovoltaic subsystems.

[0063] In addition, for the sake of brevity and ease of description, Figure 4 The transient current suppression devices 100-1, 100-2 and 100-3 in the figure only show a portion of the current suppression main circuit, while other components are omitted.

[0064] refer to Figure 4 When a fault occurs in the AC-DC converter or a grid fault in the DC microgrid, the DC-DC converter of the energy storage subsystem starts to build up the bus voltage. When the transient current suppression device 100-2 detects that the voltage at the output terminal reaches the start-up voltage, the second switch K2 is closed to connect the circuit. At this time, the second switch K1 remains open.

[0065] Here, the start-up voltage detected by the transient current suppression device 100-2 may differ from the start-up voltage detected by the transient current suppression device 100-1. As mentioned above, the start-up voltage can be pre-configured according to actual conditions and is adjustable.

[0066] For transient current suppression devices 100-1 and 100-3, when they detect a voltage at the input terminal, the first switch K1 is closed, and the second switch K2 remains open. At this time, the pre-charging path of transient current suppression devices 100-1 and 100-3 is activated, entering the pre-charging stage. The pre-charging stage can last for Δt1. By setting the resistance value of the corresponding first resistor R1, the current flowing to the power grid system and the charging pile subsystem can be controlled within a suitable range, thereby suppressing transient inrush currents.

[0067] When transient current suppression devices 100-1 and 100-3 detect that the voltage difference between the input and output terminals is less than a predetermined threshold, the second switch K2 is closed to activate the bypass path. After a predetermined time period Δt2, the first switch K1 is opened.

[0068] The predetermined threshold is associated with the voltage difference between the input and output voltages, and can be pre-configured and adjusted according to actual conditions. In one example, the predetermined threshold can be set by software and can be adjustable according to the load.

[0069] exist Figure 4 In the illustrated scenario, transient current suppression device 100-2 performs energy transfer, while transient current suppression devices 100-1 and 100-3 perform current suppression. Therefore, transient current suppression device 100 can satisfy both reverse current suppression and direct bypass control in the opposite direction.

[0070] Aside from the differences in the specific transient current suppression devices used to achieve energy transfer and transient current suppression, Figure 4 The process and Figure 3 The process is similar.

[0071] The opening and closing of the first switch K1 and the second switch K2 can be controlled by a microcontroller unit (MCU).

[0072] Similarly, the first switch K1 and the second switch K2 can be implemented by mechanical contacts or power electronic devices, ensuring the safety of the transient current suppression device 100 (100-1, 100-2, 100-3) when it fails during normal operation and when it is not in operation.

[0073] Furthermore, for the transient current suppression device 100-3 connected to the generation-consumption load branch, its pre-charge timing includes: the time period during which the first switch is closed, i.e., the pre-charge phase time period Δt1; and the predetermined time period Δt2. The pre-charge timing is based on the control timing of the load connected to the output terminal.

[0074] The values ​​of Δt1 and Δt2 can be pre-configured according to the actual situation and are adjustable.

[0075] The pre-charge timing of the transient current suppression device and the control timing of the load module can be coordinated through timing adjustments. Specifically, by pre-setting the timing, the load module can be ensured to start up only after the transient current suppression device has been bypassed. Alternatively, the timing coordination between the transient current suppression device and the load module can be achieved by sending a signal notification from the MCU 105 to the connected DC-DC converter via DIDO or communication (RS485, etc.).

[0076] Return to reference Figure 1 The microcontroller unit (MCU) 105 can be connected to the current suppression main circuit, auxiliary power supply, input voltage sampling circuit and output voltage sampling circuit.

[0077] The start-up voltage, the threshold voltage associated with the voltage difference between the input and output voltages, and the values ​​of Δt1 and Δt2 for each transient current suppression device 100 can be configured differently.

[0078] Third Embodiment

[0079] Figure 5 A schematic diagram of a transient current suppression device according to an embodiment of the present invention for detecting false voltage is shown.

[0080] When the solid-state circuit breaker is turned off, there is a certain leakage current generated when the solid-state circuit breaker is in standby mode. This leakage current generates a virtual voltage (floating voltage) at the input terminals P1 and N1.

[0081] The transient current suppression device according to the present invention can use the input voltage sampling circuit 102 to detect virtual voltage.

[0082] In one example, the MCU 105 controls the closing of the third switch K3 and the opening of the fourth switch K4, and detects the voltage at the first node Node1 between the second resistor R2 and the third resistor R3. Then, the third switch K3 is opened and the fourth switch K4 is closed, and the voltage at the second node Node2 between the fourth resistor R4 and the fifth resistor R5 is detected.

[0083] The MCU 105 can compare the voltage at the first node Node1 with the voltage at the second node Node2, and based on the comparison, determine whether the voltage at the input terminal is a false voltage.

[0084] Since the resistance ratio between the second resistor R2 and the third resistor R3 is equal to the resistance ratio between the fourth resistor R4 and the fifth resistor R5, and the resistance values ​​of the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5 are different, the voltage at the first node Node1 and the voltage at the second node Node2 should be the same under normal voltage conditions. However, in the case of a false voltage, due to the resistance of the circuit breaker, the voltage at the first node Node1 and the voltage at the second node Node2 are different.

[0085] When no false voltage is detected, the transient current suppression device 100 operates normally. When a false voltage is detected, the transient current suppression device does not activate its normal operating logic, but continues to monitor the port voltage until no false voltage is detected.

[0086] Although Figure 5 The voltage detected at the first node Node1 is labeled as Normal_vol_1 and the voltage detected at the second node Node2 is labeled as Float_vol_1. However, those skilled in the art should understand that when dummy voltages are present, the voltages detected at the first node Node1 and the second node Node2 are both dummy voltages, not normal voltages.

[0087] In one example, the MCU 105 can also be configured to keep the first and second switches open when it is determined that the voltage at the input is a false voltage.

[0088] The transient current suppression device 100 can detect false voltage when the device is powered on. If false voltage is detected, the normal operation process will not be initiated, and the port voltage will continue to be monitored, either continuously or at predetermined intervals, until the false voltage no longer exists, at which point normal operation will begin. This avoids malfunctions caused by false voltage and ensures stable operation.

[0089] In addition, the transient current suppression device 100 can also detect false voltage at any time.

[0090] Fourth embodiment

[0091] Furthermore, the transient current suppression device according to this utility model embodiment can also detect power distribution faults in the line during the pre-charging stage. When a power distribution fault occurs between the pre-charging output and the input of the generation-consumption type load, the transient current suppression device determines whether the fault exists by calculating the rise rate of the output voltage within the time that the resistance of the pre-charging path can withstand. If the voltage rise rate is lower than a set value, the pre-charging path is quickly disconnected to achieve a protective function.

[0092] Power distribution faults can include short circuits, overloads, etc.

[0093] In one example, the MCU 105 in the transient current suppression device 100 or 200 may also be configured to: detect the voltage at the third node Node3 between the sixth resistor R6 and the seventh resistor R7; determine the rate of rise of the voltage at the third node Node3; compare the rate of rise with a predetermined rate threshold; and, based on the comparison, determine whether a power distribution fault exists.

[0094] The predetermined rate threshold can be determined based on the load; that is, the predetermined rate threshold is adjustable and can depend on the load of the connection.

[0095] When a power distribution fault is detected, the MCU 105 can also be configured to disconnect the first switch K1 and the second switch K2. Furthermore, the transient current suppression device 100 can also provide a fault alarm.

[0096] Therefore, the transient current suppression device according to the present invention can also detect the false voltage generated by the leakage current generated when the solid circuit breaker is in standby mode, avoid the malfunction caused by the false voltage, ensure stable operation, and determine the line power distribution fault and perform protection by calculating the voltage rise rate during the pre-charging stage.

[0097] The DC microgrid system according to the present invention may include transient current suppression devices as described above.

[0098] Although the present invention has been described with reference to exemplary embodiments, various changes and modifications may be suggested to those skilled in the art. The present invention is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0099] Any description in this invention should not be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A transient current suppression device, characterized in that, include: A current suppression main circuit, connected between the input and output terminals, includes a pre-charge path and a bypass path, and is configured to selectively connect the input and output terminals via either the pre-charge path or the bypass path. The input voltage sampling circuit, connected to the positive and negative terminals of the input terminal, is configured to sample the input voltage. The output voltage sampling circuit, connected to the positive and negative terminals of the output, is configured to sample the output voltage. An auxiliary power supply, connected to the input and output terminals, is configured to be powered by the voltage of at least one of the input and output terminals; as well as The microcontroller unit is connected to the current suppression main circuit, auxiliary power supply, input voltage sampling circuit, and output voltage sampling circuit.

2. The transient current suppression device according to claim 1, characterized in that, The input voltage sampling circuit includes: The first path, connected between the positive and negative terminals of the input, includes a second resistor, a third resistor, and a third switch connected in series; and The second path, connected between the positive and negative terminals of the input, includes a fourth resistor, a fifth resistor, and a fourth switch connected in series. Among them, the resistance ratio between the second resistor and the third resistor is equal to the resistance ratio between the fourth resistor and the fifth resistor, and the resistance values ​​of the second resistor, the third resistor, the fourth resistor and the fifth resistor are different.

3. The transient current suppression device according to claim 2, characterized in that, The output voltage sampling circuit includes a sixth resistor and a seventh resistor connected in series.

4. The transient current suppression device according to claim 3, characterized in that: The pre-charge path, connected between the input and output terminals, includes a first switch and a first resistor connected in series. as well as The bypass path, connected between the input and output terminals, includes a second switch. The resistance value of the first resistor is set to control the magnitude of the transient current.

5. The transient current suppression device according to claim 4, characterized in that, When the voltage at the output terminal reaches the start-up voltage, the second switch is closed, while the first switch remains open.

6. The transient current suppression device according to claim 5, characterized in that, When a voltage is detected at the input terminal, the first switch is closed, and the second switch remains open. When the voltage difference between the input and output terminals is less than a predetermined threshold, the second switch is closed, and after a predetermined time period, the first switch is opened.

7. The transient current suppression device according to claim 6, characterized in that, The precharge timing is based on the control timing of the load connected to the output terminal, and the precharge timing includes the time period during which the first switch is closed and a predetermined time period.

8. The transient current suppression device according to claim 4, characterized in that, The microcontroller unit is configured as follows: When the third switch is closed and the fourth switch is open, the voltage at the first node between the second resistor and the third resistor is detected; When the third switch is open and the fourth switch is closed, the voltage at the second node between the fourth resistor and the fifth resistor is detected; Compare the voltage at the first node with the voltage at the second node; as well as Based on the comparison, it is determined whether the voltage at the input terminal is a false voltage.

9. The transient current suppression device according to claim 8, characterized in that, The microcontroller unit is also configured to keep the first and second switches open when it is determined that the voltage at the input terminal is a false voltage.

10. The transient current suppression device according to claim 8, characterized in that, The microcontroller unit is also configured as follows: Detect the voltage at the third node between the sixth and seventh resistors; Determine the rate of voltage rise at the third node; Compare the rate of ascent with the predetermined rate threshold; as well as Based on the comparison, it can be determined whether a power distribution fault exists.

11. The transient current suppression device according to claim 10, characterized in that, The microcontroller unit is also configured as follows: When a power distribution fault is detected, disconnect the first and second switches.

12. A DC microgrid system, characterized in that, Includes the transient current suppression device as described in any one of claims 1-11.

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