Solid-state circuit breaker and state detection method of solid-state circuit breaker

Abstract

The invention discloses a solid-state circuit breaker and a state detection method of the solid-state circuit breaker. The solid-state circuit breaker relates to the technical field of circuits, and comprises a solid-state switch which comprises a grid electrode, a source electrode and a drain electrode; a current sensor; a driving unit for outputting a first gate voltage and a second gate voltage to the gate; a voltage acquisition unit; the control unit is used for controlling the driving unit to output the first grid voltage, receiving the first voltage between the drain electrode and the source electrode sent by the voltage acquisition unit and receiving the current of the power supply line sent by the current sensor; and under the condition that the current of the power supply circuit is not changed, the driving unit is controlled to output a second grid voltage and receive a second voltage between the drain electrode and the source electrode sent by the voltage acquisition unit, a voltage difference value between the second voltage and the first voltage is calculated, and the state of the solid-state switch is determined according to the voltage difference value and a preset threshold value. According to the invention, the problem that the solid-state circuit breaker cannot accurately detect the state of the solid-state switch in the prior art, so that fault missing detection is caused is solved.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and more specifically, to a solid-state circuit breaker and a method for detecting the state of a solid-state circuit breaker. Background Technology

[0002] In existing solid-state circuit breakers, semiconductor switches are used as high-speed interrupting elements in the main circuit. When the semiconductor is in the off state, its failure can be determined by detecting the leakage current, absolute voltage, or impedance between the drain and source. Once the leakage current exceeds the limit or the blocking voltage is abnormal, the device can be immediately identified as having a blocking failure. However, when the semiconductor is in the on state, existing technologies can only rely on static parameters such as "absolute voltage," "absolute impedance," or "absolute drive voltage" for health assessment. When local melting, lattice damage, or metal fusion caused by cosmic rays occur inside the semiconductor, a low-resistance conductive fuze will form between its drain and source. However, the resistance value of this fuze is still on the same order of magnitude as "normal low resistance" and no longer changes with the gate voltage—that is, "the channel is locked but still has low resistance." Existing technologies misjudge such "channel-locked short circuits" as "qualified low resistance," leading to missed faults and an expanded fault range. Furthermore, to diagnose faults, existing technologies often require turning off the semiconductor before measuring the leakage current or impedance, which may not meet the needs of some scenarios where power outages are not an option.

[0003] There is currently no effective solution to the problem that solid-state circuit breakers cannot accurately detect the status of solid-state switches, resulting in missed fault detection. Summary of the Invention

[0004] The main objective of this application is to provide a solid-state circuit breaker and a method for detecting the state of a solid-state circuit breaker, so as to solve the problem that solid-state circuit breakers cannot accurately detect the state of solid-state switches in related technologies, resulting in missed fault detection.

[0005] To achieve the above objectives, the technical solution of this application is as follows: In a first aspect, embodiments of this application provide a solid-state circuit breaker, comprising: a solid-state switch including a gate, a source, and a drain, for connecting and disconnecting a power supply line; a current sensor connected in series with the solid-state switch for acquiring the current of the power supply line; a drive unit whose output terminal is connected to the gate and the source, for outputting a first gate voltage and a second gate voltage to the gate, wherein the first gate voltage is greater than the second gate voltage, and the second gate voltage is greater than a voltage threshold of the solid-state switch; a voltage acquisition unit for acquiring the voltage between the drain and the source and sending the acquired voltage signal to a control unit; and a control unit connected to the drive unit, the voltage acquisition unit, and the current sensor, for controlling the drive unit to output the first gate voltage, receiving the first voltage between the drain and the source sent by the voltage acquisition unit, and receiving the current of the power supply line sent by the current sensor, controlling the drive unit to output the second gate voltage and receiving the second voltage between the drain and the source sent by the voltage acquisition unit while the current of the power supply circuit remains unchanged, calculating the voltage difference between the second voltage and the first voltage, and determining the state of the solid-state switch based on the voltage difference and a preset threshold. Optionally, the control unit is configured to: determine that the solid-state switch is in a normal state when the voltage difference is greater than or equal to a preset threshold, and maintain the normal conduction state of the solid-state switch; and determine that the solid-state switch is in a failed state when the voltage difference is less than the preset threshold, output a fault signal, and control the drive unit to turn off the solid-state switch.

[0006] Optionally, the solid-state circuit breaker includes a surge protection device connected in parallel with the solid-state switch for protecting the solid-state switch.

[0007] Optionally, the solid-state circuit breaker includes a mechanical switch connected in series with the solid-state switch for working together to connect and disconnect the power supply line.

[0008] Secondly, embodiments of this application also provide a state detection method for a solid-state circuit breaker, applied to a solid-state circuit breaker as described in any of the first aspects. The method includes: controlling a drive unit to output a first gate voltage through a control unit and receiving a first voltage between the drain and source sent by a voltage acquisition unit; controlling a drive unit to output a second gate voltage through a control unit and receiving a second voltage between the drain and source sent by a voltage acquisition unit; calculating the voltage difference between the second voltage and the first voltage through a control unit; and determining the state of the solid-state switch based on the voltage difference and a preset threshold.

[0009] Optionally, determining the state of the solid-state switch based on the voltage difference and a preset threshold includes: determining the solid-state switch to be in a normal state when the voltage difference is greater than or equal to the preset threshold; and determining the solid-state switch to be in a failed state when the voltage difference is less than the preset threshold.

[0010] Optionally, after determining that the solid-state switch is in a failed state when the voltage difference is less than a preset threshold, the method includes: outputting a fault signal through the control unit; receiving the fault signal through the drive unit and turning off the solid-state switch.

[0011] The solid-state circuit breaker provided in this application includes: a solid-state switch, comprising a gate, a source, and a drain, for connecting and disconnecting a power supply line; a current sensor connected in series with the solid-state switch for acquiring the current of the power supply line; a drive unit, the output of which is connected to the gate and the source, for outputting a first gate voltage and a second gate voltage to the gate, wherein the first gate voltage is greater than the second gate voltage, and the second gate voltage is greater than a voltage threshold of the solid-state switch; a voltage acquisition unit for acquiring the voltage between the drain and the source and sending the acquired voltage signal to a control unit; and a control unit connected to the drive unit, the voltage acquisition unit, and the current sensor, for controlling the drive unit to output the first gate voltage, receiving the first voltage between the drain and the source sent by the voltage acquisition unit, and receiving the current of the power supply line sent by the current sensor, controlling the drive unit to output the second gate voltage and receiving the second voltage between the drain and the source sent by the voltage acquisition unit while the current of the power supply circuit remains unchanged, calculating the voltage difference between the second voltage and the first voltage, and determining the state of the solid-state switch based on the voltage difference and a preset threshold, thus solving the technical problem in the prior art where solid-state circuit breakers cannot accurately detect the state of the solid-state switch, resulting in missed fault detection. Attached Figure Description

[0012] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 A schematic diagram of a solid-state circuit breaker provided in an embodiment of this application. Figure 1 ; Figure 2 A schematic diagram of a solid-state circuit breaker provided in an embodiment of this application. Figure 2 ; Figure 3 This is a flowchart of a state detection method for a solid-state circuit breaker provided according to an embodiment of this application. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0014] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0015] Furthermore, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0016] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0017] Please refer to Figure 1 A schematic diagram of a solid-state circuit breaker provided in an embodiment of this application. Figure 1 ,like Figure 1 As shown, the solid-state circuit breaker 100 includes: a solid-state switch 101, a current sensor 102, a drive unit 103, a control unit 104, a voltage acquisition unit 105, a load, and a power supply. The solid-state switch 101 includes a gate, a source, and a drain, used to connect and disconnect the power supply line 110; the current sensor 102 is connected in series with the solid-state switch 101, used to acquire the current of the power supply line 110; the output terminal of the drive unit 103 is connected to the gate and the source, used to output a first gate voltage and a second gate voltage to the gate, wherein the first gate voltage is greater than the second gate voltage, and the second gate voltage is greater than the voltage threshold of the solid-state switch; the voltage acquisition unit 105 is used to acquire the voltage between the drain and the source and send the acquired voltage signal to the control unit 104; the control unit 104 and... The drive unit 103, voltage acquisition unit 105, and current sensor 102 are connected to control the drive unit 103 to output a first gate voltage, receive a first voltage between the drain and source sent by the voltage acquisition unit 105, and receive the current of the power supply line sent by the current sensor 102. When the current of the power supply circuit remains unchanged, the drive unit 103 is controlled to output a second gate voltage and receive a second voltage between the drain and source sent by the voltage acquisition unit 105. The voltage difference between the second voltage and the first voltage is calculated, and the state of the solid-state switch 101 is determined according to the voltage difference and a preset threshold.

[0018] It should be noted that the solid-state switch 101 includes a gate, a source, and a drain. The gate and source are the output terminals of the solid-state switch, and the drain is the control terminal of the solid-state switch.

[0019] It should be noted that the control unit controls the drive unit to output a first gate voltage V1 and a second gate voltage V2. The first gate voltage, the second gate voltage, and the voltage threshold V of the solid-state switch are also considered. th The magnitudes of the gate voltages satisfy the following relationship: first gate voltage > second gate voltage > voltage threshold of the solid-state switch. Outputting the first gate voltage V1 to the gate enables the solid-state switch to be in a deeply on state. The current at this time is collected by the current sensor as I, and the voltage between the drain and source at this time is collected by the voltage acquisition device as V. a Then, with the current I remaining constant, a second gate voltage V2 is output to the gate, and the voltage between the drain and source at this time is collected by a voltage acquisition device as V. b ; Calculate V b and V a The voltage difference is used to determine if the solid-state switch 101 has failed when the voltage difference is less than a preset threshold. This solves the problem of existing solid-state circuit breakers performing status detection after power failure, judging conduction health based on absolute voltage, absolute impedance, or absolute drive voltage. When the solid-state switch is open, its operation can be judged by the voltage across its terminals, but when the solid-state switch is in the conducting state, it is difficult to distinguish between normal conduction and failure short circuit, resulting in missed fault detection and losses.

[0020] Optionally, outputting a first gate voltage V1 to the gate can put the solid-state switch in a deep conduction state. The first gate voltage V1 maximizes the width of the conductive channel, that is, the cross-sectional area of ​​the conductive channel inside the semiconductor reaches its maximum. At this time, the on-resistance enters the plateau region, and the V measured at this time... a This refers to the lowest voltage drop achievable under the rated current I. With the current I constant, a second gate voltage V2 is output to the gate, and the value of V2 can be set to satisfy V1>V2>V. th The size of V2 can also be set to V th + 1 V ≤ V2≤ V1 2 V, the voltage threshold of a solid-state switch. th It is the turn-on threshold voltage of the solid-state switch, therefore V2 must be greater than V. th Or set V2 to be greater than V th + 1 V, etc., set V2 to be greater than V. th +1 V prevents current collapse due to incomplete opening of the conductive channel. Because V aThis is the lowest voltage drop achievable at the rated current I. If the solid-state switch is short-circuited, the conductive channel width will not change. In other words, if the solid-state switch is short-circuited, the voltage between the drain and source will not decrease as the gate voltage decreases. V b Approximately equal to or equal to V a The voltage difference is approximately equal to or equal to 0, therefore V can be calculated by outputting a second gate voltage V2 to the gate. b and V a The voltage difference is used to determine whether the solid-state switch has failed by comparing the voltage difference with a preset threshold. For example, the preset threshold could be 0.1V. b and V a If the voltage difference is less than 0.1V, the solid-state switch is determined to be faulty.

[0021] In one optional embodiment, after the control drive unit outputs a first gate voltage and receives a first voltage between the drain and source sent by the voltage acquisition unit, it receives a first current in the power supply line sent by the current sensor. To maintain a constant line current, the control drive unit outputs a second gate voltage. This can be achieved by activating a constant current control mode through the control unit, keeping the current in the power supply circuit at the first current. Then, the control drive unit outputs the second gate voltage and receives a second voltage between the drain and source sent by the voltage acquisition unit. Disabling the constant current control mode restores the system to its natural voltage source operation, avoiding the additional heat and power consumption caused by prolonged constant current operation.

[0022] In one optional embodiment, the control unit 104 is configured to: determine that the solid-state switch is in a normal state when the voltage difference is greater than or equal to a preset threshold, and maintain the normal conduction state of the solid-state switch; and determine that the solid-state switch is in a failed state when the voltage difference is less than the preset threshold, output a fault signal and control the drive unit to turn off the solid-state switch.

[0023] For example, the preset threshold could be 0.1V, if V b and V a If the voltage difference is 0.2V, then the solid-state switch is determined to be in a normal conducting state. If V b and V a If the voltage difference is 0, the solid-state switch is determined to be in a failed state. Then, a fault signal can be output and the drive unit can be controlled to turn off the solid-state switch.

[0024] like Figure 2 A schematic diagram of a solid-state circuit breaker provided in an embodiment of this application. Figure 2 ,and Figure 1Unlike the solid-state circuit breaker, the solid-state circuit breaker also includes a mechanical switch 106, connected in series with the solid-state switch 101, used together to connect and disconnect the power supply line 110. After the control unit of the solid-state circuit breaker outputs a fault signal, the fault signal can trigger the mechanical trip coil, causing the contacts of the mechanical switch to separate, forming an air gap. The current will then be almost zero, thereby disconnecting the power supply line 110. When the solid-state switch 101 fails, the mechanical switch 106 can replace the solid-state switch 101 to disconnect the power supply line 110, further improving the safety and reliability of the solid-state circuit breaker of this invention.

[0025] In an alternative embodiment, the solid-state circuit breaker may further include a surge protection device connected in parallel with the solid-state switch for protecting the solid-state switch.

[0026] Optionally, the surge protection device is connected in parallel with the solid-state switch to clamp transient overvoltages occurring in the power supply line to a safe voltage, thereby protecting the solid-state switch from overvoltage breakdown. The surge protection device can be a metal oxide varistor (MOV), a transient voltage suppressor diode (TVS), or an RC snubber circuit, connected in parallel with the drain and source of the solid-state switch; when the line experiences lightning strikes, switch surges, or other disturbances... V / d t During peak periods, the surge protection device can turn on within seconds to bypass transient energy, ensuring that the voltage across the solid-state switch is always lower than its rated withstand voltage, thus extending the service life of the solid-state switch.

[0027] Figure 3 This is a flowchart of a state detection method for a solid-state circuit breaker according to an embodiment of this application. The method includes the following steps: In step S301, the control unit controls the drive unit to output the first gate voltage and receives the first voltage between the drain and source sent by the voltage acquisition unit.

[0028] In step S302, the control unit controls the drive unit to output the second gate voltage and receives the second voltage between the drain and source sent by the voltage acquisition unit.

[0029] Step S303: The voltage difference between the second voltage and the first voltage is calculated by the control unit.

[0030] Step S304: Determine the state of the solid-state switch based on the voltage difference and a preset threshold.

[0031] Optionally, in this embodiment, the first gate voltage and the second gate voltage satisfy the following condition: first gate voltage V1 > second gate voltage V2 > voltage threshold of the solid-state switch. For example, the voltage threshold of the solid-state switch is 7V. The control unit controls the driving unit to output V1 to the gate, where V1 is 15V. V1 maximizes the width of the conductive channel and receives the first voltage V between the drain and source sent by the voltage acquisition unit. a The voltage is 1.2V. Then, the current sensor measures the current at this time as I=1000A. Within tens of µs (e.g., <50µs), the control drive unit outputs a second gate voltage V2, which is 8V, to maintain the current at 1000A. The second voltage V between the drain and source is received from the voltage acquisition unit. b The voltage is 1.4V. Calculate the second voltage V. b and the first voltage V a If the voltage difference is 0.2V, and the voltage difference is greater than a preset threshold (e.g., the preset threshold is 0.1V), the solid-state switch can be determined to be in a normal state. Therefore, it is possible to accurately determine whether the solid-state switch is in a faulty or normal state without interrupting power.

[0032] Optionally, in the state detection method for solid-state circuit breakers provided in this application embodiment, determining the state of the solid-state switch based on the voltage difference and a preset threshold includes: determining the solid-state switch to be in a normal state when the voltage difference is greater than or equal to the preset threshold; and determining the solid-state switch to be in a failed state when the voltage difference is less than the preset threshold.

[0033] For example, the first voltage V a The voltage is 1.4V, and the second voltage V b The voltage is 1.4V, and the voltage difference is 0V, which is less than the preset threshold of 0.1V. Therefore, the solid-state switch is in a failed state.

[0034] Optionally, to maintain a constant line current while controlling the drive unit to output a second gate voltage, a constant current control mode can be activated by the control unit, keeping the power supply circuit current at the first current. After acquiring the second voltage, the state of the solid-state switch can be determined by comparing the voltage difference between the second and first voltages with a preset threshold. Then, the system's natural voltage source operation can be restored, avoiding the additional heat generation and power consumption caused by long-term constant current.

[0035] Optionally, in the state detection method for a solid-state circuit breaker provided in this application embodiment, after determining that the solid-state switch is in a failed state when the voltage difference is less than a preset threshold, the method includes: outputting a fault signal through a control unit; receiving the fault signal through a drive unit and turning off the solid-state switch.

[0036] Optionally, the control unit compares the voltage difference between the second voltage and the first voltage with a preset threshold. If the voltage difference is less than the preset threshold, the control unit can determine that the solid-state switch is in a failed state. Then, the control unit can output a fault signal and send the fault signal to the drive circuit. The drive circuit can turn off the solid-state switch by reducing the gate voltage to 0V.

[0037] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A solid-state circuit breaker, characterized in that, The solid-state circuit breaker includes: Solid-state switches, which include a gate, a source, and a drain, are used to turn power lines on and off. A current sensor, connected in series with the solid-state switch, is used to collect the current of the power supply line; A driving unit, the output terminal of which is connected to the gate and the source, is used to output a first gate voltage and a second gate voltage to the gate, wherein the first gate voltage is greater than the second gate voltage and the second gate voltage is greater than the voltage threshold of the solid-state switch; A voltage acquisition unit is used to acquire the voltage between the drain and the source and send the acquired voltage signal to the control unit; The control unit, connected to the drive unit, the voltage acquisition unit, and the current sensor, is used to control the drive unit to output a first gate voltage, receive a first voltage between the drain and the source sent by the voltage acquisition unit, and receive the current of the power supply line sent by the current sensor. While keeping the current of the power supply line constant, the control unit is also used to output a second gate voltage and receive a second voltage between the drain and the source sent by the voltage acquisition unit. The control unit calculates the voltage difference between the second voltage and the first voltage, and determines the state of the solid-state switch based on the voltage difference and a preset threshold.

2. The solid-state circuit breaker according to claim 1, characterized in that, The control unit is used for: If the voltage difference is greater than or equal to the preset threshold, the solid-state switch is determined to be in a normal state, and the normal conduction state of the solid-state switch is maintained. If the voltage difference is less than the preset threshold, the solid-state switch is determined to be in a fault state, a fault signal is output, and the drive unit is controlled to turn off the solid-state switch.

3. The solid-state circuit breaker according to claim 1, characterized in that, The solid-state circuit breaker includes: A surge protection device, which is connected in parallel with the solid-state switch, is used to protect the solid-state switch.

4. The solid-state circuit breaker according to claim 1, characterized in that, The solid-state circuit breaker includes: A mechanical switch, connected in series with the solid-state switch, is used together with the solid-state switch to connect and disconnect the power supply line.

5. A condition detection method for a solid-state circuit breaker, characterized in that, Applied to a solid-state circuit breaker as described in any one of claims 1-4, the method comprises: The control unit controls the driving unit to output a first gate voltage and receives the first voltage between the drain and the source sent by the voltage acquisition unit. The control unit controls the driving unit to output a second gate voltage and receives a second voltage between the drain and the source sent by the voltage acquisition unit. The control unit calculates the voltage difference between the second voltage and the first voltage; The state of the solid-state switch is determined based on the voltage difference and the preset threshold.

6. The method according to claim 5, characterized in that, Determining the state of the solid-state switch based on the voltage difference and the preset threshold includes: If the voltage difference is greater than or equal to the preset threshold, the solid-state switch is determined to be in a normal state. If the voltage difference is less than the preset threshold, the solid-state switch is determined to be in a failed state.

7. The method according to claim 6, characterized in that, After determining that the solid-state switch is in a failed state when the voltage difference is less than the preset threshold, the method includes: The control unit outputs a fault signal. The drive unit receives the fault signal and shuts off the solid-state switch.

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