Solid state circuit breaker and reclosing method thereof

Abstract

The present disclosure relates to a solid state circuit breaker and a reclosing method thereof. The solid state circuit breaker includes a control unit configured to control to drive the solid state circuit breaker with a first drive voltage in a case where it is determined that the solid state circuit breaker needs to perform reclosing, and control to drive the solid state circuit breaker with a second drive voltage greater than the first drive voltage after a predetermined time if a cut-off drive signal is not received. The reliability of the solid state circuit breaker can be improved, and effective protection can be provided to a load line.

Description

Technical Field

[0001] This disclosure relates to a solid-state circuit breaker and a reclosing method thereof. Background Technology

[0002] Solid-state circuit breakers (SSDs) are a new type of circuit breaker in power distribution systems. SSDs replace some mechanical structures with power electronic devices; for example, the power switching elements in an SSD can be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). This gives SSDs many advantages that traditional circuit breakers do not possess. For instance, the closing and opening speeds of SSDs are far faster than those of mechanical circuit breakers, making it possible to quickly limit fault currents. Simultaneously, the control of SSDs is more precise than that of mechanical circuit breakers, thus providing faster and more accurate protection for downstream power distribution equipment. Furthermore, the inherent digital characteristics of SSDs enable the implementation of complex application control and protection logic.

[0003] In addition, solid-state circuit breakers, as protective devices, often trip due to abnormal operating conditions. Common abnormal operating conditions include heat accumulation and self-protection. Self-protection is generally divided into self-protection caused by line short circuits and self-protection caused by surges or lightning strikes. In the case of self-protection caused by a short circuit, reclosing cannot be performed before the short circuit fault is cleared; while in the case of self-protection caused by a surge or lightning strike, since the surge or lightning strike is often short-lived, reclosing can be performed after a period of time. Summary of the Invention

[0004] This disclosure relates to a solid-state circuit breaker and its reclosing method. In the case of a solid-state circuit breaker tripping due to self-protection, the current is controlled during the reclosing process of the solid-state circuit breaker based on remote control, which greatly improves the reliability of the solid-state circuit breaker and provides effective protection for the load line.

[0005] According to a first aspect of this disclosure, a solid-state circuit breaker is provided. The solid-state circuit breaker includes a control unit configured to: control the solid-state circuit breaker to be driven with a first drive voltage when it is determined that the solid-state circuit breaker needs to perform reclosing; and control the solid-state circuit breaker to be driven with a second drive voltage greater than the first drive voltage if no disconnection drive signal is received after a predetermined time.

[0006] According to a second aspect of this disclosure, a reclosing method for a solid-state circuit breaker is provided. The solid-state circuit breaker includes a control unit, and the reclosing method includes, when the control unit determines that the solid-state circuit breaker needs to perform reclosing: the control unit controls the solid-state circuit breaker to be driven with a first drive voltage; and if no disconnection drive signal is received after a predetermined time, the control unit controls the solid-state circuit breaker to be driven with a second drive voltage greater than the first drive voltage. Attached Figure Description

[0007] The aspects, features, and advantages of this disclosure will become clearer and more readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0008] Figure 1 This is a schematic diagram of a solid-state circuit breaker according to an embodiment of the present disclosure.

[0009] Figure 2 An example current characteristic of a MOSFET is shown.

[0010] Figure 3 An example current characteristic of a MOSFET is shown.

[0011] Figure 4 This is a flowchart of a reclosing method for a solid-state circuit breaker according to an embodiment of the present disclosure. Detailed Implementation

[0012] The present disclosure will now be described in detail with reference to exemplary embodiments thereof. However, the present disclosure is not limited to the embodiments described herein, which may be implemented in many different forms. The described embodiments are provided only to make the present disclosure thorough and complete, and to fully convey the concept of the present disclosure to those skilled in the art. Features of the various embodiments described may be combined with or substituted for each other, unless expressly excluded or should be excluded based on the context.

[0013] While current solid-state circuit breakers have gained numerous advantages through the introduction of power electronic devices, they also face some new challenges. For example, power electronic devices have high requirements for voltage and current; it is necessary to ensure that the voltage and current remain within the range required by the power electronic device in real time to prevent damage. Furthermore, different measures are needed to address the different abnormal operating conditions that cause solid-state circuit breaker tripping, as described above, when reclosing the solid-state circuit breaker under remote control.

[0014] The embodiments of this disclosure propose a solid-state circuit breaker and its reclosing method. Addressing the situation where the solid-state circuit breaker trips due to self-protection, during the reclosing process under remote control, the solid-state circuit breaker is initially kept in a semi-conducting state with a low conducting current. Through a series of judgments, the solid-state circuit breaker is eventually fully turned on, thus controlling the current during reclosing. This ensures that even if there is an anomaly at the load end (such as a short circuit) during reclosing, there will be no large current surge in the load line, thereby greatly improving the reliability of the solid-state circuit breaker and providing effective protection for the load line.

[0015] Figure 1This is a schematic diagram of a solid-state circuit breaker 100 according to an embodiment of the present disclosure. The solid-state circuit breaker 100 may include a MOSFET 110 as a power switching element, a drive voltage generation unit 120, a current detection and judgment unit 130, a drive unit 140, and a control unit 150. The process of reclosing the solid-state circuit breaker 100 in the event of a trip due to self-protection is as follows: First, the solid-state circuit breaker 100 (specifically, the MOSFET 110) can be driven with a first drive voltage V1, causing the solid-state circuit breaker 100 (specifically, the MOSFET 110) to be in a semi-conducting state. Thus, even if there is an abnormality at the load end (e.g., a short circuit), a large current surge will not occur in the load line, because the current at this time will not exceed the saturation current of the MOSFET 110 when driven with the first drive voltage V1. Next, a series of judgments can be made to determine whether the solid-state circuit breaker 100 can be fully turned on to achieve reclosing of the solid-state circuit breaker 100. The above determination can be indicated by cutting off the drive signal. If the disconnection drive signal is not received after a predetermined time, the solid-state circuit breaker 100 can be driven with a second drive voltage V2 greater than the first drive voltage V1 to make it fully open. The process described above is described in detail below through the cooperation of the various components of the solid-state circuit breaker 100.

[0016] When it is determined that the solid-state circuit breaker 100 needs to perform reclosing, the control unit 150 can control the solid-state circuit breaker 100 to be driven with a first drive voltage V1. In one embodiment, the first drive voltage V1 can be a drive voltage that puts the MOSFET 110 in a semi-conducting state. In one embodiment, controlling the solid-state circuit breaker 100 to be driven with the first drive voltage V1 can be performed as follows: the drive voltage generation unit 120 can generate the first drive voltage V1 under the control of the control unit 150 and pass it to the drive unit 140; the drive unit 140 can apply the received first drive voltage V1 to the gate of the MOSFET 110, thereby putting the MOSFET 110 in a semi-conducting state, that is, a state of being turned on but not overdriven. In one embodiment, the first drive voltage V1 can be the threshold voltage V of the MOSFET 110. th and Miller voltage V miller This allows the MOSFET 110 to be in a semi-conducting state. In one embodiment, the first drive voltage V1 can be close to the Miller voltage V0 of the MOSFET 110. miller .

[0017] Based on the characteristics of a MOSFET, when the MOSFET 110 is driven by the first driving voltage V1, the MOSFET 110 is in a semi-conducting state, and its drain-source current I... DS Limited by saturation current. Figure 2 An example current characteristic of a MOSFET is shown. See also Figure 2For example, for a given MOSFET, at the gate-source voltage V GS At 8V, the saturation current is approximately 45A, and the drain-source current I... DS Limited by the saturation current, it will not be particularly large. Therefore, even if there is an abnormality at the load end (such as a short circuit), a large current surge will not occur in the load line. Moreover, the drain-source current I of MOSFET 110 can be used as a reference. DS Comparison with the saturation current helps determine if there is an abnormality at the load end (such as a short circuit).

[0018] The current detection and judgment unit 130 can perform the above comparison and judgment. For example, the current detection and judgment unit 130 can detect the drain-source current I of the MOSFET 110. DS and the drain-source current I DS With the predetermined current threshold I th The predetermined current threshold I is compared. th This can be less than the saturation current of the MOSFET 110 when the gate of the MOSFET 110 is subjected to the first drive voltage V1. For example, in the above... Figure 2 In the example, the saturation current is approximately 45A, then the predetermined current threshold I th It can be, for example, 40A. If there is an abnormality at the load end (e.g., a short circuit), the drain-source current I... DS It will be very close to the saturation current, and therefore will be greater than the predetermined current threshold I. th Otherwise, if there is no abnormality at the load end, the drain-source current I... DS It will be less than the predetermined current threshold I th Therefore, if the drain-source current I DS Greater than the predetermined current threshold I th If the current detection and judgment unit 130 determines that there is an abnormality at the load end (e.g., a short circuit), the solid-state circuit breaker 100 should not perform a reclosing operation, and thus sends a disconnection drive signal S to the drive unit 140 and the control unit 150. shutoff .

[0019] If the drive unit 140 receives the aforementioned cut-off drive signal S shutoff Then the application of the first driving voltage V1 to the gate of MOSFET 110 can be stopped, thereby turning off MOSFET 110, opening the solid-state circuit breaker, and terminating the reclosing process.

[0020] If the current detection and judgment unit 130 does not send the cut-off drive signal S shutoff This indicates that there is no abnormality at the load end, meaning that the previous tripping of the solid-state circuit breaker 100 was caused by a surge or lightning strike rather than a short circuit, and therefore reclosing can be performed. Therefore, if the control unit 150 does not receive the aforementioned tripping drive signal S after a predetermined time... shutoffThen, the control unit 150 can control the solid-state circuit breaker 100 to be driven with a second driving voltage V2 greater than the first driving voltage V1. In one embodiment, the second driving voltage V2 can be a driving voltage that puts the MOSFET 110 in a fully on state. In one embodiment, controlling the solid-state circuit breaker 100 to be driven with the second driving voltage V2 can be performed as follows: the driving voltage generation unit 120 can generate the second driving voltage V2 under the control of the control unit 150 and pass it to the driving unit 140; the driving unit 140 can then apply the second driving voltage V2 to the gate of the MOSFET 110, thereby putting the MOSFET 110 in a fully on state, i.e., a fully overdriven state. At this time, the MOSFET 110 operates in the variable resistance region, is in the on state as a power switching element, and the reclosing process is completed. In one embodiment, the second driving voltage V2 can be greater than the Miller voltage of the MOSFET 110. In one embodiment, the second driving voltage V2 can be the voltage required for normal driving of the MOSFET 110, i.e., the voltage required to sufficiently overdrive the MOSFET 110.

[0021] Since MOSFET 110 is initially driven by the first driving voltage V1 and is in a semi-conducting state, its internal resistance is very high, and its junction temperature rises rapidly. Therefore, the time elapsed from the start of driving MOSFET 110 with the first driving voltage V1 until driving MOSFET 110 with the second driving voltage V2 cannot be too long. Thus, in one embodiment, the maximum value of the predetermined time can correspond to the time t1 during which the junction temperature of MOSFET 110 reaches its maximum junction temperature under the first driving voltage V1. That is, the second driving voltage V2 must be applied to the gate of MOSFET 110 within time t1. As is known, for a given MOSFET, t1 can be based on the current I of the MOSFET when the gate is subjected to the first driving voltage V1. DS The calculation is based on the internal resistance and transient thermal resistance of the MOSFET.

[0022] After the driving unit 140 applies the second driving voltage V2 to the gate of the MOSFET 110, the current in the MOSFET 110 can be further detected to terminate the reclosing process and disconnect the solid-state circuit breaker 100 in a timely manner when an abnormality is detected. An abnormality could be a partial short circuit at the load end (incomplete short circuit, such as a short circuit in part of the equipment at the load end), in which case reclosing is still not suitable. Therefore, in one embodiment, the current detection and judgment unit 130 continuously detects the drain-source current I of the MOSFET 110. DS and compare it with the predetermined current threshold I th Compare, and respond to the drain-source current I DS Greater than the predetermined current threshold I thA cut-off drive signal is sent to the drive unit 140 and the control unit 150. After the drive unit 140 applies the second drive voltage V2 to the gate of the MOSFET 110, the drive unit 140 can also respond to the cut-off drive signal S from the current detection and judgment unit 130. shutoff Stop applying the second drive voltage V2 to the gate of MOSFET 110.

[0023] In one embodiment, whether a reclosing process can be performed also depends on whether the MOSFET 110 is functioning correctly. When the solid-state circuit breaker 100 trips due to self-protection, the temperature of the MOSFET 110 may be very high, affecting its normal operation. Therefore, the reclosing process should only begin after the MOSFET 110 has cooled to a certain level. Its normal operation can be determined based on the junction temperature and case temperature of the MOSFET 110. Furthermore, as... Figure 2 and Figure 3 As shown, the saturation current of the MOSFET varies depending on its junction temperature Tj. From... Figure 2 and Figure 3 It can be seen that the higher the junction temperature Tj of the MOSFET, the larger the aforementioned saturation current. Consequently, when the MOSFET 110 is driven by the first drive voltage V1, the current in the load circuit will also be larger, which is detrimental to providing protection for the load circuit. Therefore, it is desirable that the junction temperature of the MOSFET not be too high.

[0024] In one embodiment, before the control unit 150 controls the drive voltage generation unit 120 to generate the first drive voltage V1, it can be determined whether a time threshold t2 has elapsed, which indicates whether the junction temperature of the MOSFET has dropped to a normal range. If the time threshold t2 has elapsed, it can be assumed that the junction temperature of the MOSFET has dropped to a normal range, thus allowing reclosing. That is, in one embodiment, determining that the solid-state circuit breaker 100 needs to perform reclosing may include determining that a time threshold t2 has elapsed since the previous trip of the solid-state circuit breaker 110. The time threshold t2 can be set according to user requirements. For example, the time threshold t2 may correspond to the time it takes for the junction temperature of the MOSFET 110 to drop from its maximum junction temperature to a predetermined temperature. For example, the maximum junction temperature of the MOSFET is typically 120°C. The predetermined temperature may be the case temperature of the MOSFET, typically between 80°C and 105°C. As is known, the time threshold t2 can be calculated based on the transient thermal resistance of the MOSFET, the maximum junction temperature, and the predetermined temperature. For a given MOSFET, the time threshold may be an inherent parameter.

[0025] In one embodiment, before the control unit 150 controls the drive voltage generation unit 120 to generate the first drive voltage V1, it can also be determined whether the case temperature of the MOSFET 110 is within the normal range. That is, in one embodiment, determining that the solid-state circuit breaker 100 needs to perform reclosing may further include: determining that the case temperature of the MOSFET 110 is less than a temperature threshold T1. That is, if it is determined that the case temperature of the MOSFET 110 is less than the temperature threshold T1, it can be determined that the case temperature of the MOSFET 110 is within the normal range, and thus it can operate normally. The time threshold T1 can be set according to user requirements. In one embodiment, the temperature threshold T2 can be equal to the maximum junction temperature of the MOSFET 110 minus the maximum junction-to-case temperature difference. For example, the maximum junction temperature of the MOSFET can typically be 120°C. Furthermore, as is known, the maximum junction-to-case temperature difference can be calculated based on the power and thermal resistance of the MOSFET, where the power depends on the current I when the MOSFET was previously disconnected. DS For example, if the maximum junction temperature of a MOSFET is 120°C and the calculated maximum junction-to-case temperature difference is 25°C, then the temperature threshold T1 is equal to 95°C.

[0026] The solid-state circuit breaker of the present disclosure can control the current during reclosing, ensuring that even if there is an abnormality at the load end (such as a short circuit) during reclosing, there will be no large current surge in the load line, thereby greatly improving the reliability of the solid-state circuit breaker and providing effective protection for the load line.

[0027] Figure 4 This is a flowchart of a reclosing method 400 for a solid-state circuit breaker according to an embodiment of the present disclosure. The solid-state circuit breaker can be, for example, the one described above. Figure 1 The solid-state circuit breaker 100 is described below. (Followed by...) Figure 1 The reclosing method 400 is described in detail.

[0028] Method 400 begins at step S410, wherein if control unit 150 determines that solid-state circuit breaker 100 needs to perform reclosing, control unit 150 may control solid-state circuit breaker 100 to be driven with a first drive voltage V1. In one embodiment, the first drive voltage V1 may be a drive voltage that puts MOSFET 110 in a semi-conducting state. In one embodiment, step S410 may be performed as follows: drive voltage generation unit 120 may generate the first drive voltage V1 under the control of control unit 150 and pass it to drive unit 140; drive unit 140 may apply the received first drive voltage V1 to the gate of MOSFET 110, thereby putting MOSFET 110 in a semi-conducting state, i.e., a state of conduction but not overdrive. In one embodiment, the first drive voltage V1 may be a threshold voltage V of MOSFET 110. th and Miller voltage V millerThis allows the MOSFET 110 to be in a semi-conducting state. In one embodiment, the first drive voltage V1 can be close to the Miller voltage V0 of the MOSFET 110. miller .

[0029] In step S420, the control unit 150 can determine whether it has received a cut-off drive signal S. shutoff Cut off drive signal S shutoff The current can be sent by the current detection and judgment unit 130. In one embodiment, the current detection and judgment unit 130 can detect the drain-source current I of the MOSFET 110. DS and the drain-source current I DS With the predetermined current threshold I th Comparisons can be made, and responses can be made to the drain-source current I. DS Greater than the predetermined current threshold I th Send a cut-off drive signal S to control unit 150 shutoff The predetermined current threshold I th It can be less than the saturation current of MOSFET 110 when the gate of MOSFET 110 is subjected to a first drive voltage V1. If the control unit 150 does not receive a cut-off drive signal S from the current detection and judgment unit 130 after a predetermined time t1. shutoff In step S430, the control unit 150 can control the solid-state circuit breaker 100 to be driven with a second driving voltage V2 greater than the first driving voltage V1. The second driving voltage can be a driving voltage that puts the MOSFET 110 in a fully on state. In one embodiment, step S430 can be performed as follows: the driving voltage generation unit 120 can generate the second driving voltage V2 under the control of the control unit 150 and pass it to the driving unit 140; the driving unit 140 can apply the second driving voltage V2 to the gate of the MOSFET 110, thereby putting the MOSFET 110 in a fully on state, i.e., a fully overdriven state. At this time, the MOSFET 110 operates in the variable resistance region and is in the on state as a power switching element, and the reclosing process is completed. In one embodiment, the second driving voltage V2 can be greater than the Miller voltage V of the MOSFET 110. miller In one embodiment, the second driving voltage V2 can be the voltage required for normal driving of the MOSFET 110, that is, the voltage required to overdrive the MOSFET 110 sufficiently.

[0030] In one embodiment, the current detection and judgment unit 130 can also send a drive cut-off signal S to the drive unit 140. shutoff Furthermore, the drive unit 140 can also determine in step S420 whether it has received the cut-off drive signal S sent by the current detection and judgment unit 130. shutoff If the drive unit 140 determines that it has received the cut-off drive signal Sshutoff In step S440, the drive unit 140 can respond to the cut-off drive signal S shutoff Stop applying the first drive voltage V1 to the gate of MOSFET 110, thereby turning off MOSFET 110, opening the solid-state circuit breaker, and terminating the reclosing process.

[0031] In one embodiment, method 400 may further include, after step S430: after the driving unit 140 applies the second driving voltage V2 to the gate of the MOS transistor, the driving unit 140 may respond to the cut-off driving signal S from the current detection and judgment unit 130. shutoff Stop applying the second drive voltage V2 to the gate of the MOSFET.

[0032] In one embodiment, determining that the solid-state circuit breaker 100 needs to perform reclosing may include: the control unit 150 determining that a time threshold t2 has elapsed since the previous trip of the solid-state circuit breaker 100, wherein the time threshold t2 may correspond to the time it takes for the junction temperature of the MOSFET to drop from the maximum junction temperature to a predetermined temperature.

[0033] In one embodiment, determining that the solid-state circuit breaker 100 needs to perform reclosing may further include: the control unit 150 determining that the case temperature of the MOSFET is less than a temperature threshold T1, wherein the temperature threshold T1 may be equal to the maximum junction temperature of the MOSFET minus the maximum junction-case temperature difference.

[0034] In one embodiment, the maximum value of the predetermined time t1 can correspond to the time it takes for the junction temperature of the MOSFET to reach its maximum junction temperature under the drive of the first drive voltage V1.

[0035] The reclosing method of the solid-state circuit breaker in the embodiments of this disclosure can control the current during the reclosing process, ensuring that even if there is an abnormality at the load end (such as a short circuit) during reclosing, there will be no large current surge in the load line, thereby greatly improving the reliability of the solid-state circuit breaker and providing effective protection for the load line.

[0036] It is important to note that although the steps are described in a specific order above, this should not be interpreted as requiring these steps to be performed in the specific order or sequence described.

[0037] The block diagrams of the apparatuses, devices, and systems disclosed herein are merely exemplary and are not intended to require or imply that connections, arrangements, or configurations must be made in the manner shown in the block diagrams. As those skilled in the art will recognize, these circuits, devices, apparatuses, and systems can be connected, arranged, and configured in any manner that achieves the desired purpose.

[0038] The processes and logic flows described in this specification can be executed by one or more programmable processors that execute one or more computer programs to perform functions by manipulating input data and generating output. The processes and logic flows can also be executed by dedicated logic circuits, and the apparatus can be implemented as dedicated logic circuits, such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). For example, the drive voltage generation unit 120 can be implemented using any voltage generation circuit known in the art, the current detection and judgment unit 130 can be implemented using any current detection and comparison circuit known in the art, the control unit 150 can be a microcontroller unit (MCU), and so on.

[0039] Although the operations are described in a specific order in the accompanying drawings, this should not be construed as requiring that these operations be performed in the specific order or sequence shown, or requiring that all the operations shown be performed to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous.

[0040] Certain features described in the context of individual embodiments in this specification may also be combined. Conversely, various features described in the context of individual embodiments may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0041] Those skilled in the art should understand that the specific embodiments described above are merely examples and not limitations. Various modifications, combinations, partial combinations, and substitutions can be made to the embodiments of this disclosure according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, and thus fall within the scope of the rights to be protected by this disclosure.

Claims

1. A solid-state circuit breaker, comprising a control unit, wherein, upon determining that the solid-state circuit breaker needs to perform reclosing, the control unit is configured to: Control to drive the solid-state circuit breaker with a first drive voltage; and If no disconnection drive signal is received after a predetermined time, the solid-state circuit breaker is driven with a second drive voltage greater than the first drive voltage. The solid-state circuit breaker also includes a MOSFET as a power switching element, wherein, The first driving voltage is a driving voltage that puts the MOSFET in a semi-conducting state, and the second driving voltage is a driving voltage that puts the MOSFET in a fully conducting state. The solid-state circuit breaker further includes a current detection and judgment unit, which detects the drain-source current of the MOSFET and compares the drain-source current with a predetermined current threshold, and sends the cut-off drive signal in response to the drain-source current being greater than the predetermined current threshold, wherein the predetermined current threshold is less than the saturation current of the MOSFET when the gate of the MOSFET is subjected to the first drive voltage.

2. The solid-state circuit breaker according to claim 1 further includes a drive voltage generation unit and a drive unit, wherein, Controlling the solid-state circuit breaker to drive with the first drive voltage or the second drive voltage includes: The driving voltage generation unit generates the first driving voltage or the second driving voltage under the control of the control unit, and transmits the first driving voltage or the second driving voltage to the driving unit; and The driving unit applies the first driving voltage or the second driving voltage to the gate of the MOS transistor.

3. The solid-state circuit breaker according to claim 1, wherein, Determining that the solid-state circuit breaker needs to perform reclosing includes: the control unit determining that a time threshold has elapsed since the previous trip of the solid-state circuit breaker, wherein the time threshold corresponds to the time it takes for the junction temperature of the MOSFET to drop from the maximum junction temperature to a predetermined temperature.

4. The solid-state circuit breaker according to claim 3, wherein, Determining that the solid-state circuit breaker needs to perform reclosing further includes: the control unit determining that the case temperature of the MOSFET is less than a temperature threshold, wherein the temperature threshold is equal to the maximum junction temperature of the MOSFET minus the maximum junction-case temperature difference.

5. The solid-state circuit breaker according to claim 1, wherein, The maximum value of the predetermined time corresponds to the time it takes for the junction temperature of the MOS transistor to reach its maximum junction temperature under the drive of the first drive voltage.

6. The solid-state circuit breaker according to claim 1, wherein, The first driving voltage is between the threshold voltage and Miller voltage of the MOSFET.

7. The solid-state circuit breaker according to claim 1, wherein, The second driving voltage is greater than the Miller voltage of the MOS transistor.

8. The solid-state circuit breaker according to claim 2, wherein, The driving unit is further configured to stop applying the first driving voltage or the second driving voltage to the gate of the MOS transistor in response to receiving the cut-off driving signal.

9. A reclosing method for a solid-state circuit breaker, the solid-state circuit breaker including a control unit, the reclosing method comprising, when the control unit determines that the solid-state circuit breaker needs to perform reclosing: The solid-state circuit breaker is driven by the control unit with a first drive voltage; and If no disconnection drive signal is received after a predetermined time, the control unit will control the solid-state circuit breaker to be driven with a second drive voltage greater than the first drive voltage. The solid-state circuit breaker further includes a MOSFET as a power switching element, the first driving voltage is a driving voltage that puts the MOSFET in a semi-conducting state, and the second driving voltage is a driving voltage that puts the MOSFET in a fully conducting state. The solid-state circuit breaker further includes a current detection and judgment unit, and the reclosing method further includes: The current detection and judgment unit detects the drain-source current of the MOS transistor and compares the drain-source current with a predetermined current threshold, and sends the cut-off drive signal in response to the drain-source current being greater than the predetermined current threshold, wherein the predetermined current threshold is less than the saturation current of the MOS transistor when the gate of the MOS transistor is subjected to the first drive voltage.

10. The reclosing method according to claim 9, wherein, The solid-state circuit breaker further includes a drive voltage generation unit and a drive unit, wherein the control unit controls the solid-state circuit breaker to be driven with the first drive voltage or the second drive voltage, comprising: The driving voltage generation unit generates the first driving voltage or the second driving voltage under the control of the control unit, and transmits the first driving voltage or the second driving voltage to the driving unit; and The driving unit applies the first driving voltage or the second driving voltage to the gate of the MOS transistor.

11. The reclosing method according to claim 9, wherein, Determining that the solid-state circuit breaker needs to perform reclosing includes: the control unit determining that a time threshold has elapsed since the previous trip of the solid-state circuit breaker, wherein the time threshold corresponds to the time it takes for the junction temperature of the MOSFET to drop from its maximum junction temperature to a predetermined temperature.

12. The reclosing method according to claim 11, wherein, Determining that the solid-state circuit breaker needs to perform reclosing further includes: the control unit determining that the case temperature of the MOSFET is less than a temperature threshold, wherein the temperature threshold is equal to the maximum junction temperature of the MOSFET minus the maximum junction-case temperature difference.

13. The reclosing method according to claim 9, wherein, The maximum value of the predetermined time corresponds to the time it takes for the junction temperature of the MOS transistor to reach its maximum junction temperature under the drive of the first drive voltage.

14. The reclosing method according to claim 9, wherein, The first driving voltage is between the threshold voltage and Miller voltage of the MOSFET.

15. The reclosing method according to claim 9, wherein, The second driving voltage is greater than the Miller voltage of the MOS transistor.

16. The reclosing method according to claim 10, further comprising: The driving unit stops applying the first driving voltage or the second driving voltage to the gate of the MOS transistor in response to receiving the cut-off driving signal.

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