Switching circuit, solid-state switch and detection method

Abstract

The invention provides a switch circuit, a solid-state switch and a detection method, and belongs to the technical field of power electronics, the switch circuit comprises a switch unit, the switch unit is connected in series on a power supply line, the switch unit comprises a first connecting end, a second connecting end and a control end, the first connecting end is electrically connected with a power supply end of the power supply line; the second connecting end is electrically connected with the power receiving end of the power supply line; the first detection unit is configured to collect a first voltage signal and a first current signal of the power supply end of the power supply line; the second detection unit is configured to collect a second voltage signal and a second current signal of the power receiving end of the power supply line; and the control unit is configured to send a control signal to the control end to cut off the power supply line under the condition of determining that the power supply line has an abnormal state, and through the switching circuit provided by the invention, rapid, accurate and reliable diagnosis and cut-off protection of the abnormal state of the power supply line can be realized.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a switching circuit, a solid-state switch, and a detection method. Background Technology

[0002] In fields such as DC power distribution systems, new energy power generation, electric vehicles, and industrial control, there is a need for fast and reliable on / off control of high-power DC circuits. The traditional solution is to use mechanical contactors or circuit breakers. However, mechanical switches generate arcs when interrupting large currents, leading to contact erosion, limited lifespan, and slow operating speed (usually tens of milliseconds or more), which cannot meet the high requirements of applications that require extremely fast interruption of fault currents (e.g., at the microsecond level). Summary of the Invention

[0003] In view of the above problems, embodiments of this application provide a switching circuit, a solid-state switch, and a detection method to overcome or at least partially solve the above problems.

[0004] In a first aspect, this application provides a switching circuit, comprising: a switching unit connected in series on a power supply line, the switching unit including a first connection terminal, a second connection terminal, and a control terminal, the first connection terminal being electrically connected to the power supply terminal of the power supply line, and the second connection terminal being electrically connected to the power receiving terminal of the power supply line; a first detection unit, the input terminal of the first detection unit being electrically connected to the first connection terminal, configured to acquire a first voltage signal and a first current signal from the power supply terminal of the power supply line; a second detection unit, the input terminal of the second detection unit being electrically connected to the second connection terminal, configured to acquire a second voltage signal and a second current signal from the power receiving terminal of the power supply line; and a control unit, the input terminal of the control unit being electrically connected to the first detection unit, the second detection unit, and the control terminal respectively; wherein the control unit is configured to send a control signal to the control terminal to disconnect the power supply line when it is determined, based on the first voltage signal, the first current signal, the second voltage signal, and the second current signal, that an abnormal state exists in the power supply line.

[0005] In some embodiments, the switching unit includes: a first switch and a second switch; wherein a first terminal of the first switch is electrically connected to the power supply terminal of the power supply line, a second terminal of the first switch is electrically connected to the second terminal of the second switch, a first terminal of the second switch is electrically connected to the power receiving terminal of the power supply line, and the control terminals of the first switch and the second switch are respectively electrically connected to the control unit; the control unit is configured to send the control signal to the first switch and the second switch in the event of an abnormality in the power supply line.

[0006] In some embodiments, the switching unit further includes: a first capacitor, a second capacitor, and an inductor; wherein, a first terminal of the first capacitor is electrically connected to a first terminal of the first switch, a first terminal of the second capacitor is electrically connected to a first terminal of the second switch, a second terminal of the first capacitor and a second terminal of the second capacitor are grounded, a first terminal of the inductor is electrically connected to a second terminal of the first switch, and a second terminal of the inductor is electrically connected to a second terminal of the second switch.

[0007] In some embodiments, the switching unit further includes a third switch and a fourth switch; wherein, a first terminal of the third switch is electrically connected to a second terminal of the first switch, a first terminal of the fourth switch is electrically connected to a second terminal of the second switch, the second terminals of the third switch and the fourth switch are grounded, and the control terminals of the third switch and the fourth switch are electrically connected to the control unit.

[0008] In some embodiments, the switching circuit further includes a temperature detection unit electrically connected to the control unit; the temperature detection unit is configured to detect the temperature of the first switch and the second switch; the control unit is further configured to send the control signal to the first switch and the second switch when the temperature exceeds a preset temperature threshold.

[0009] In some embodiments, the switching circuit further includes: a communication unit and an input / output control unit; wherein the communication unit and the input / output control unit are electrically connected to the control unit via communication interfaces.

[0010] A second aspect of this application provides a solid-state switch, comprising: a housing, a heat sink, and a switching circuit as described in the first aspect of this application; wherein the heat sink and the switching circuit are disposed inside the housing, and the switching unit is connected to the heat sink.

[0011] In some embodiments, the solid-state switch further includes: a main power interface, wherein the main power interface is disposed on the side wall of the housing, and the main power interface includes an input positive copper busbar, a negative copper busbar, and an output positive copper busbar arranged side by side; wherein the input positive copper busbar is electrically connected to the power supply terminal of the power supply line, the output positive copper busbar is electrically connected to the power receiving terminal of the power supply line, and the negative copper busbar is electrically connected to both the power supply terminal and the power receiving terminal.

[0012] In a third aspect of this application, a detection method for a switching circuit is provided, applied to a control unit in a switching circuit of a first aspect of this application. The detection method includes: acquiring a first current signal, a first voltage signal, a second current signal, and a second voltage signal on a power supply line; determining whether an abnormal state exists in the power supply line based on the first voltage signal, the first current signal, the second voltage signal, and the second current signal; wherein the abnormal state includes at least one of an overvoltage abnormal state, an overcurrent abnormal state, and a short-circuit abnormal state; and controlling a switching unit to disconnect the power supply line when an abnormal state exists in the power supply line.

[0013] In some embodiments, determining whether the power supply line has an abnormal state includes: determining that the power supply line has an overvoltage abnormal state when the voltages of the first voltage signal and the second voltage signal exceed a preset voltage threshold; determining that the power supply line has an overcurrent abnormal state when the first current signal and the second current signal exceed a preset current threshold; and determining that the power supply line has a short-circuit abnormal state when the first current signal and / or the second current signal exceed a short-circuit current threshold.

[0014] The switching circuit provided in this embodiment includes a switching unit, a first detection unit, a second detection unit, and a control unit. Since the first connection terminal of the switching unit is electrically connected to the power supply terminal of the power supply line, and the second connection terminal is electrically connected to the power receiving terminal of the power supply line, the input terminal of the first detection unit is electrically connected to the first terminal of the switching unit, and the input terminal of the second detection unit is electrically connected to the second connection terminal of the switching unit, the first detection unit is configured to collect a first voltage signal and a first current signal from the power supply terminal of the power supply line, and the second detection unit is configured to collect a second voltage signal and a second current signal from the power receiving terminal of the power supply line. Therefore, the first and second detection units can be synchronized. The system monitors the voltage and current information at the power supply and receiving ends of the power supply line. The input terminal of the control unit is electrically connected to the first detection unit, the second detection unit, and the control terminal, respectively. The control unit is configured to send a control signal to the control terminal of the switching unit to disconnect the power supply line when an abnormal state is determined based on the first voltage signal, the first current signal, the second voltage signal, and the second current signal. Therefore, it can meet the requirements of rapid response and automatic protection of the switching circuit to faults, effectively prevent the abnormal state from further expanding, and thus ensure the safe and stable operation of the entire power supply system where the power supply line is located. It realizes rapid, accurate, and reliable diagnosis and disconnection protection of abnormal states of the power supply line. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a system schematic diagram of a switching circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of the circuit structure of a switching unit provided in an embodiment of this application; Figure 3 This is a schematic diagram of a discharge circuit for a switching circuit provided in an embodiment of this application; Figure 4 This is a system schematic diagram of another switching circuit provided in the embodiments of this application; Figure 5 This is a schematic diagram of the circuit structure of a communication unit provided in an embodiment of this application; Figure 6 This is a schematic diagram of the circuit structure of an input / output control unit provided in an embodiment of this application; Figure 7 This is a schematic diagram of the sampling circuit boards of the first and second detection units provided in the embodiments of this application; Figure 8 This is a schematic diagram of the current sampling circuit in the first and second detection units provided in the embodiments of this application; Figure 9 This is a schematic diagram of the voltage sampling circuit in the first detection unit provided in the embodiment of this application; Figure 10 This is a schematic diagram of the voltage sampling circuit in the second detection unit provided in the embodiments of this application; Figure 11 This is a schematic diagram of the overcurrent protection circuit in the control unit provided in the embodiment of this application; Figure 12 This is a schematic diagram of the drive circuit 1 in the control unit provided in the embodiment of this application; Figure 13 This is a schematic diagram of the second drive circuit in the control unit provided in the embodiment of this application; Figure 14 This is a schematic diagram of the drive board circuit in the control unit provided in the embodiment of this application; Figure 15 This is a schematic diagram of the circuit structure of a temperature detection unit provided in an embodiment of this application; Figure 16This is a schematic diagram of the main power interface of the solid-state switch provided in an embodiment of this application; Figure 17 This is a flowchart of a detection method for a switching circuit provided in an embodiment of this application; Figure 18 This is a flowchart illustrating the steps involved in applying a solid-state switch to a power supply line, as provided in an embodiment of this application. Figure label: 1-Switch unit; 2-First detection unit; 3-Second detection unit; 4-Control unit; 5-Temperature detection unit; 6-Communication unit; 7-Communication interface; 8-Input / output control unit; 9-Input positive copper busbar; 10-Negative copper busbar; 11-Output positive copper busbar; Q1-First switch; Q2-Second switch; Q3-Third switch; Q4-Fourth switch; C1-First capacitor; C2-Second capacitor; L-Inductor. Detailed Implementation

[0017] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0018] Figure 1 This is a system schematic diagram of a switching circuit provided in an embodiment of this application. Figure 1 As can be seen from the diagram, there is a switch unit 1 connected in series on the power supply line. The switch unit 1 includes a first connection terminal, a second connection terminal, and a control terminal. The first connection terminal is electrically connected to the power supply end of the power supply line, and the second connection terminal is electrically connected to the power receiving end of the power supply line. There is a first detection unit 2, whose input terminal is electrically connected to the first connection terminal and is configured to collect a first voltage signal and a first current signal from the power supply end of the power supply line. There is a second detection unit 3, whose input terminal is electrically connected to the second connection terminal and is configured to collect a second voltage signal and a second current signal from the power receiving end of the power supply line. There is a control unit 4, whose input terminal is electrically connected to the first detection unit 2, the second detection unit 3, and the control terminal, respectively. The control unit 4 is configured to send a control signal to the control terminal to cut off the power supply line when it is determined that there is an abnormal state in the power supply line based on the first voltage signal, the first current signal, the second voltage signal, and the second current signal.

[0019] In this embodiment, the power supply line can be any power transmission path that needs to be monitored and protected by the switching circuit. Specifically, the power supply line mainly refers to the current path from the power source (power supply end) to the load (power receiving end).

[0020] Switching unit 1 can be a switching device controlled by control unit 4, used to perform the switching on and off of the power supply line. Switching unit 1 can be a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT). Switching unit 1 is connected in series with the power supply line. The control signal is a signal that controls the switching unit to turn on or off. The control signal can be a digital signal, a PWM signal, or an analog signal, which can be adjusted according to the needs of the power supply line. Therefore, switching unit 1 can receive the control signal from control unit 4 to maintain the power supply line in a conducting state, or it can receive the control signal from control unit 4 to cut off the power supply line. In this embodiment, the control signal is used to turn off switching unit 1; other uses are similar and will not be repeated here.

[0021] The first detection unit 2 can be a high-precision signal acquisition unit responsible for monitoring the electrical parameters of the power supply line input side. Since the input terminal of the first detection unit 2 is electrically connected to the first terminal of the switching unit 1, it is configured to acquire the first voltage signal and the first current signal of the power supply line input terminal. Therefore, the voltage sampling part of the first detection unit 2 can be a high-input-impedance voltage divider resistor network to accurately acquire the input voltage without causing a significant load effect on the power supply line; the current sampling part of the first detection unit 2 can use a sampling resistor in conjunction with a differential amplifier, Hall current sensor, or current transformer to achieve non-contact or low-loss measurement of the target power supply current. The first detection unit 2 can condition (e.g., amplify, filter) the acquired analog voltage and current signals and can directly output or convert them into digital signals to provide to the control unit 4, serving as the basis for the control unit 4 to determine the total input energy and state of the power supply line input side.

[0022] The second detection unit 3 can be a signal sampling unit that is symmetrical or similar to the first detection unit 2 in function and structure. Since the input terminal of the second detection unit 3 is electrically connected to the second terminal of the switch unit 1, it is configured to collect the second voltage signal and the second current signal of the output terminal of the power supply line. The voltage sampling part and the current sampling part of the second detection unit 3 can be the same as those in the first detection unit 2. Then, the second voltage signal and the second current signal sampled by the second detection unit 3 are transmitted to the control unit 4. The control unit 4 can calculate the voltage drop and power loss of the switch unit 1 itself and the intermediate line by comparing the data (first voltage signal, second voltage signal, first current signal and second current signal) of the first detection unit 2 and the second detection unit 3, so as to diagnose faults such as abnormal line impedance, aging of contact points, short circuit or open circuit of load on the power supply line.

[0023] Control unit 4 can be a core processor with logic operation and decision-making capabilities. Control unit 4 can be a microcontroller (MCU), digital signal processor (DSP), or programmable logic device (CPLD / FPGA). Control unit 4 internally has pre-set or runs fault diagnosis algorithms. Since the input terminals of control unit 4 are electrically connected to the output terminals of the first detection unit 2 and the second detection unit 3 respectively, control unit 4 can diagnose whether the power supply line is in an abnormal state by comparing and calculating the first current signal, second current signal, first voltage signal, and second voltage signal from the power supply end and the power receiving end in real time. For example, it can determine whether there is overvoltage / undervoltage, overcurrent, input / output power mismatch, abnormally increased voltage difference, etc. Furthermore, since the output terminal of control unit 4 is electrically connected to the control terminal of switch unit 1, when control unit 4 determines that the power supply line is in an abnormal state, it sends a clear control signal to the control terminal of switch unit 1 (such as the coil of a relay or the gate of a MOSFET). The control signal can be a level transition or a change in a PWM signal, driving switch unit 1 to act, thereby quickly and automatically cutting off the power supply line and achieving safety protection.

[0024] In summary, the switching circuit provided in this embodiment can automatically shut down the power supply line in a very short time when faults such as overvoltage, overcurrent, undervoltage, and short circuit are detected in the power supply line through the coordinated operation of the switching unit 1, the first detection unit 2, the second detection unit 3, and the control unit 4. This significantly improves the reliability and safety of the power supply system and effectively prevents the expansion of faults and equipment damage.

[0025] Figure 2 This is a circuit structure diagram of a switching unit provided in an embodiment of this application. Figure 2As can be seen from the diagram, the switch unit 1 includes: a first switch Q1 and a second switch Q2; wherein, the first end of the first switch Q1 is electrically connected to the power supply end of the power supply line, the second end of the first switch Q1 is electrically connected to the second end of the second switch Q2, the first end of the second switch Q2 is electrically connected to the power receiving end of the power supply line, and the control ends of the first switch Q1 and the second switch Q2 are respectively electrically connected to the control unit 4; the control unit 4 is configured to send control signals to the first switch Q1 and the second switch Q2 in the event of an abnormality in the power supply line.

[0026] In this embodiment, the first switch Q1 is a controlled switching device connected in series at the power supply end of the power supply line, and the second switch Q2 is a controlled switching device connected in series at the power receiving end of the power supply line. The first switch Q1 and the second switch Q2 can be IGBTs or MOSFETs. The specific selection can be made according to the specific requirements of the power supply line.

[0027] The first switch Q1 controls the input path of the power supply. When the control unit 4 sends a control signal to the control terminal of the first switch Q1, the first switch Q1 is turned off, which disconnects the connection between the power supply terminal and the power source, achieving effective isolation of the power supply terminal. The second switch Q2 controls the output path of the power supply. When the control unit 4 sends a control signal to the control terminal of the second switch Q2, the second switch Q2 is turned off, which disconnects the connection between the power receiving terminal and the load, achieving effective isolation of the power receiving terminal.

[0028] Because of their high efficiency and low on-resistance, IGBTs enable more efficient power regulation, significantly improving the overall efficiency of the device. Secondly, IGBTs have extremely fast switching speeds, completing switching operations in a short time, making them suitable for high-frequency circuits and thus improving system performance. Furthermore, IGBTs can withstand large currents and voltages, making them suitable for high-power and high-voltage applications. Due to their high integration density, IGBTs can achieve higher power output in a smaller space. IGBTs also have good thermal conductivity, enabling stable operation in high-temperature environments. Finally, IGBTs have excellent insulation properties, effectively preventing electromagnetic interference and improving system safety; therefore, using IGBTs as power electronic switches is preferable.

[0029] When the first switch Q1 and the second switch Q2 are IGBTs, since the second terminal of the first switch Q1 is electrically connected to the second terminal of the second switch Q2, from Figure 2As can be seen, the emitters of the first switch Q1 and the second switch Q2 are electrically connected, forming a common-emitter back-to-back series structure. When there is an abnormality in the power supply line, a disconnection signal is sent to the first switch Q1 and the second switch Q2. When the first switch Q1 and the second switch Q2 are in the off state, the high voltage at the power supply end and the power receiving end will be shared by the first switch Q1 and the second switch Q2, reducing the voltage stress on individual devices, improving the withstand voltage level, and the back-to-back series structure of the first switch Q1 and the second switch Q2 constitutes a bidirectional blocking unit. Regardless of whether the fault current comes from the power supply or the load, there is always one IGBT that can effectively disconnect it, providing redundant protection. Even if one IGBT fails and short-circuits, the other IGBT can still perform the action of disconnecting the power supply line, preventing the fault from spreading and enhancing the robustness of the power supply system in which the power supply line is located.

[0030] Continue to refer to Figure 2 The switching unit 1 further includes: a first capacitor C1, a second capacitor C2, and an inductor L; wherein, the first end of the first capacitor C1 is electrically connected to the first end of the first switch Q1, the first end of the second capacitor C2 is electrically connected to the first end of the second switch Q2, the second ends of the first capacitor C1 and the second ends of the second capacitor C2 are grounded, the first end of the inductor L is electrically connected to the second end of the first switch Q1, and the second end of the inductor L is electrically connected to the second end of the second switch Q2.

[0031] In this embodiment, the first capacitor C1 serves as a spike absorption capacitor or a DC bus support capacitor in the power supply line. It provides a local low-impedance path for the voltage from the power input, absorbs high-frequency noise and voltage spikes at the power supply end, provides a stable and clean operating voltage for the first switch Q1, and, when the first switch Q1 is rapidly turned on, because it can instantly provide a large inrush current, it can prevent excessive voltage drops caused by the inductance L of the power supply line, thereby protecting the first switch Q1 and reducing the impact on the power supply.

[0032] The second capacitor C2 acts as an output spike absorption capacitor in the power supply line. It can eliminate the high-frequency ripple generated by the operation of the first switch Q1 and the second switch Q2, provide a more stable and continuous DC voltage to the load at the receiving end, and provide continuous current to the load at the moment when the second switch Q2 is turned off, maintain the stability of the output voltage, and suppress voltage fluctuations in the load.

[0033] Inductor L serves as an energy storage and filtering element in the power supply line. Connected between the first switch Q1 and the second switch Q2, inductor L stores magnetic field energy. During switch-off periods, inductor L releases energy to maintain current continuity. The inherent characteristics of inductor L prevent sudden changes in current within the power supply line, effectively suppressing current spikes generated during the switching of the first switch Q1 and the second switch Q2. This also protects the first switch Q1, the second switch Q2, the first capacitor C1, and the second capacitor C2.

[0034] Continue to refer to Figure 2 The switching unit 1 further includes a third switch Q3 and a fourth switch Q4; wherein, the first end of the third switch Q3 is electrically connected to the second end of the first switch Q1, the first end of the fourth switch Q4 is electrically connected to the second end of the second switch Q2, the second ends of the third switch Q3 and the fourth switch Q4 are grounded, and the control ends of the third switch Q3 and the fourth switch Q4 are electrically connected to the control unit 4.

[0035] In this embodiment, the third switch Q3 and the fourth switch Q4 can also be controlled switching devices, similar to the first switch Q1 and the second switch Q2. Specifically, they can be IGBTs or MOSFETs. Since residual energy remains in the first capacitor C1, the second capacitor C2, the inductor L, and the line after the first switch Q1 and the second switch Q2 disconnect the power supply line, a discharge circuit is introduced, consisting of the body diodes in the third switch Q3 and the fourth switch Q4 and the body diodes in the first switch Q1 and the second switch Q2, to discharge the residual energy in order to quickly and safely release this residual energy and prevent it from causing electric shock or interfering with the power supply line status monitoring.

[0036] Specifically, when control unit 4 detects a fault and controls the first switch Q1 and the second switch Q2 to turn off, the entire power supply line is physically disconnected. However, the electrical energy stored in the first capacitor C1, the second capacitor C2, the inductor L, and the circuit cannot disappear instantly, causing critical nodes (such as the common connection point of the first switch Q1 and the second switch Q2) to maintain a dangerously high voltage for a prolonged period. Since control unit 4 sends control signals to the third switch Q3 and the fourth switch Q4 before the power supply line is turned on, the third switch Q3 and the fourth switch Q4 are in an open state. The body diodes in the third switch Q3 and the fourth switch Q4 can form a discharge path with the body diodes in the first switch Q1 and the second switch Q2. Figure 3 This is a schematic diagram of the discharge circuit of a switching circuit provided in an embodiment of this application. Figure 3 As can be seen from this, the switching circuit includes two discharge paths, namely path one and path two.

[0037] Path 1: With the second switch Q2 and the third switch Q3 open, the residual charge on the inductor L, the second capacitor C2, and the power supply terminal of the power supply line can be released sequentially through the second switch Q2 and the third switch Q3.

[0038] Path 2: When the first switch Q1 and the fourth switch Q4 are open, the residual charge on the inductor L, the first capacitor C1, and the power receiving end of the power supply line can be released sequentially through the first switch Q1 and the fourth switch Q4.

[0039] Therefore, by using path one and path two, it is possible to avoid the residual charge from being superimposed on subsequent operations (such as misoperation or re-powering) in an unknown state, thus preventing surge current damage to the first switch Q1 and the second switch Q2.

[0040] Figure 4 This is a system schematic diagram of another switching circuit provided in the embodiments of this application, from... Figure 4 As can be seen from the diagram, the switching circuit also includes a temperature detection unit 5, which is electrically connected to the control unit 4. The temperature detection unit 5 is configured to detect the temperature of the first switch Q1 and the second switch Q2. The control unit 4 is also configured to send control signals to the first switch Q1 and the second switch Q2 when the temperature exceeds a preset temperature threshold.

[0041] In this embodiment, the failure of the power switching devices (first switch Q1 and second switch Q2) is often caused by overheating. For example, under conditions of overload, abnormal drive, or poor heat dissipation, even if the current and voltage have not yet reached the instantaneous danger value, the temperature of the switching devices may rise sharply due to heat accumulation, leading to performance degradation or even permanent damage. Therefore, during the operation of the first switch Q1 and the second switch Q2, it is also necessary to detect the temperature of the first switch Q1 and the second switch Q2. The temperature detection unit 5 can detect the temperature of the first switch Q1 and the second switch Q2. Specifically, the temperature detection unit 5 can be a temperature detection circuit. This temperature detection circuit is close to or integrated on the casing or heat sink of the first switch Q1 and the second switch Q2. It can detect the temperature of the first switch Q1 and the second switch Q2 and generate a temperature analog signal or a temperature digital signal, which is transmitted to the control unit 4. The control unit 4 can set a preset temperature threshold, which is the highest temperature that the first switch Q1 and the second switch Q2 can withstand in the working state. When the control unit 4 determines that the temperature of the first switch Q1 and the second switch Q2 exceeds the preset temperature threshold, it sends a control signal to the first switch Q1 and the second switch Q2 to forcibly cut off the power supply line, thereby realizing active thermal protection of the power switching devices, effectively preventing the first switch Q1 and the second switch Q2 from entering a thermal runaway state due to overheating, and fundamentally avoiding permanent damage caused by excessive temperature.

[0042] Continue to refer to Figure 4 The switching circuit also includes a communication unit 6 and an input / output control unit 8; wherein the communication unit 6 and the input / output control unit 8 are electrically connected to the control unit 4 through a communication interface 7.

[0043] In this embodiment, the communication unit 6 is an interface circuit responsible for exchanging data with external systems or higher-level controllers. Specific implementations may include a CAN bus controller, an RS-485 / 232 transceiver, an Ethernet PHY chip, or a wireless communication module (such as Wi-Fi or Bluetooth). Figure 5 This is a schematic diagram of the circuit structure of a communication unit provided in an embodiment of this application. Figure 5 As can be seen from the diagram, communication unit 6 includes both CAN and RS485, both using standard communication circuits. Specifically, communication unit 6 can be TD301MCAN or RSM485M, featuring signal isolation, electrical isolation, high transmission rate, and good noise immunity. Communication unit 6 can achieve bidirectional signal transmission with control unit 4 through communication interface 7.

[0044] The input / output control unit 8 is an interface expansion circuit responsible for processing local digital signal inputs and driving local actuators. Specifically, it can consist of digital input channels, relay drive circuits, or optocoupler-isolated output circuits. Figure 6 This is a schematic diagram of the circuit structure of an input / output control unit provided in an embodiment of this application. Figure 6 As can be seen from the diagram, the input of the input / output control unit 8 uses an active I / O control circuit, and the output uses a passive I / O control circuit. I / O control of the input / output unit is performed through an external interface. In this embodiment, the communication interface 7 can be an interface board integrating a universal asynchronous transceiver, a serial peripheral interface, a CAN interface, an Ethernet interface, and a digital input / output interface, enabling the control unit 4 to establish communication connections with different external devices.

[0045] In addition, in order to ensure that the switching circuit can quickly and automatically cut off the power supply line and achieve safety protection, it is also necessary to describe the circuits corresponding to the first detection unit 2, the second detection unit 3, the control unit 4 and the temperature detection unit 5 in this embodiment.

[0046] Figure 7 This is a schematic diagram of the sampling circuit boards of the first and second detection units provided in the embodiments of this application. Figure 7As can be seen, the sampling circuit detects and samples the input and output voltages in real time, and transmits the sampled values ​​to the control unit 4 for monitoring and corresponding processing. The voltage sensor can be the LEM LV25-P, which uses closed-loop Hall effect technology and has high accuracy and good linearity. For current sampling, the Hall current sensor HAS 600-S / SP50 can be used, with a measurement range of 0~±900A, a secondary signal of 30mA, a measurement accuracy of 1%, and a power supply voltage of 15V, meeting the usage requirements. Figure 7 J1 in the circuit connects the positive terminal of the power supply line to the positive terminal of the power supply line, and J4 connects the negative terminal of the power supply line to the negative terminal of the power supply line.

[0047] Figure 8 This is a schematic diagram of the current sampling circuit in the first and second detection units provided in the embodiments of this application. Figure 8 As can be seen from the diagram, the current sampling circuit consists of two operational amplifier stages. The first stage, U10B, is a 2:1 non-inverting operational amplifier circuit, which reduces the current sampling input source by a factor of 2. The second stage, U10A, is a 1:1 non-inverting operational amplifier circuit, capable of receiving the first and second current signals output by the sampling circuit. The input terminal of the current sampling circuit is electrically connected to the output terminal of the current Hall effect sensor, and the output terminal of the current sampling circuit is electrically connected to the control unit 4.

[0048] Figure 9 This is a schematic diagram of the voltage sampling circuit in the first detection unit provided in the embodiments of this application. Figure 9 It can be seen that the input terminal of voltage sampling circuit one is... Figure 7 The output terminal (2 in J2) of the sampling circuit board is electrically connected, 1 in J2 is connected to the positive terminal of the power supply, and 1 in J2 is connected to the negative terminal of the power supply. The power supply can be a 15V power supply. The output terminal of the voltage sampling circuit is electrically connected to the control unit 4.

[0049] Figure 10 This is a schematic diagram of the voltage sampling circuit in the second detection unit provided in the embodiments of this application. Figure 10 It can be seen that the input terminal of voltage sampling circuit two is... Figure 7 The output terminal of the sampling circuit board (2 in J2) is electrically connected to the control unit 4.

[0050] The control unit 4 can be composed of an overcurrent protection circuit, a drive circuit, and a drive circuit board.

[0051] Figure 11 This is a schematic diagram of the overcurrent protection circuit in the control unit provided in an embodiment of this application. Figure 11As can be seen from the diagram, the overcurrent protection circuit is composed of the comparator circuit of the operational amplifier. The output terminal has two states: when there is no overcurrent, the output is high level and the voltage can be 5V; when an overcurrent is detected, the output is low level and the voltage can be -15V.

[0052] Figure 12 This is a schematic diagram of the drive circuit in the control unit provided in the embodiment of this application. Figure 12 As can be seen, the driving circuit mainly drives and controls the first switch Q1. The driving circuit uses optical signals for driving, and fiber optic transceivers HFBR-2522Z and HFBR-1522Z can be selected to send driving signals and feedback signals to drive and control the first switch Q1, respectively. Among them, PWM1 triggers the control unit 4 to output control signals to the first switch Q1.

[0053] Figure 13 This is a schematic diagram of the second drive circuit in the control unit provided in the embodiment of this application. Figure 13 As can be seen, the driving circuit mainly drives and controls the second switch Q2. The driving circuit uses optical signals for driving, and fiber optic transceivers HFBR-2522Z and HFBR-1522Z can be selected to send driving signals and feedback signals to drive and control the second switch Q2, respectively. Among them, PWM2 is the signal that triggers the control unit 4 to output control signals to the second switch Q2.

[0054] Figure 14 This is a schematic diagram of the drive board circuit in the control unit provided in the embodiments of this application. Figure 14 As can be seen, G2 of the driver board circuit is electrically connected to the control terminal of the first switch Q1, and G1 of the driver board circuit is electrically connected to the control terminal of the second switch Q2. The driver board circuit is controlled by the PWM1 signal to control the conduction and cutoff of the first switch Q1, and the driver board circuit is controlled by the PWM2 signal to control the conduction and cutoff of the second switch Q2.

[0055] Figure 15 This is a schematic diagram of the circuit structure of a temperature detection unit provided in an embodiment of this application. Figure 15 As can be seen from the diagram, the temperature detection unit 5 includes two input terminals, TEMP1 and TEMP2 respectively. TEMP1 can receive the voltage signal corresponding to the temperature of the first switch Q1, and TEMP2 can receive the voltage signal corresponding to the temperature of the second switch Q2. The output terminal of the temperature detection unit 5 is electrically connected to the control unit 4.

[0056] This application also provides a solid-state switch, including: a housing, a heat sink, and a switching circuit according to the first aspect of this application; wherein the heat sink and the switching circuit are disposed inside the housing, and the switching unit 1 is connected to the heat sink.

[0057] In this embodiment, the housing is the external structural component of the solid-state switch, providing physical encapsulation and protection for the internal switching circuit and other components. The heat sink is the component for heat transfer between the first switch Q1 and the second switch Q2. When the first switch Q1 and the second switch Q2 are in operation, the heat generated can be transferred through the heat sink. The heat sink can dissipate the heat into the air inside the housing through convection and radiation, thereby reducing the temperature of the first switch Q1 and the second switch Q2 during operation.

[0058] In addition, if the heat sink cannot achieve the desired heat dissipation effect, a cooling fan can be added to the housing to enhance the heat dissipation effect on the first switch Q1 and the second switch Q2.

[0059] Figure 16 This is a schematic diagram of the main power interface of the solid-state switch provided in an embodiment of this application. Figure 16 As can be seen from the above, the solid-state switch also includes: a main power interface, wherein the main power interface is located on the side wall of the housing, and the main power interface includes an input positive copper busbar 9, a negative copper busbar 10 and an output positive copper busbar 11 arranged side by side; wherein the input positive copper busbar 9 is electrically connected to the power supply end of the power supply line, the output positive copper busbar 11 is electrically connected to the power receiving end of the power supply line, and the negative copper busbar 10 is electrically connected to both the power supply end and the power receiving end.

[0060] In this embodiment, the main power interface is the physical port for electrical connection and power transmission between the solid-state switch and the external power supply line. The main power interface is located on the side wall of the housing, facilitating parallel installation and bus-type connection in the distribution cabinet or equipment. The parallel arrangement of the input positive copper busbar 9, negative copper busbar 10, and output positive copper busbar 11 effectively reduces the overall size of the terminals and helps balance the distributed inductance L, suppressing electromagnetic interference generated during high-current switching. The input positive copper busbar 9 is the access point for the external power supply. Inside the housing, it is reliably connected to the input terminal of the first detection module and the first terminal of the first switch Q1 in the switching circuit via thick wires, busbars, or direct soldering, introducing external power into the solid-state switch without loss. The output positive copper busbar 11 is the contact point for supplying power to the load. Inside the housing, it is also reliably connected to the first terminal of the second switch Q2 and the output terminal of the second detection module in the switching circuit via a low-impedance connection. Its function is to safely and reliably deliver the power, controlled and processed by the internal switching circuit, to the external load. The negative copper busbar 10 serves as a common return path for both input and output current. This means that the negative terminals of the power supply and the power receiving (load) terminals are directly connected at the solid-state switch interface, simplifying external wiring, reducing the number of connectors, ensuring a consistent current sensing reference, and improving measurement accuracy. Furthermore, the input positive copper busbar 9 and the output positive copper busbar 11 can be interchanged, supporting bidirectional interchangeability of the solid-state switch.

[0061] Figure 17 This is a flowchart illustrating the steps of a detection method for a switching circuit provided in an embodiment of this application, applied to a control unit in the switching circuit of the first aspect of this application embodiment. Figure 17 As can be seen from this, the process includes: Step S171: Acquire the first current signal, the first voltage signal, the second current signal, and the second voltage signal on the power supply line.

[0062] In this embodiment, combined with Figure 1 The control unit controls the power supply line to be turned on, and then obtains the first current signal, the first voltage signal, the second current signal and the second voltage signal through the first detection unit and the second detection unit.

[0063] Step S172: Based on the first voltage signal, the first current signal, the second voltage signal, and the second current signal, determine whether there is an abnormal state in the power supply line; wherein, the abnormal state includes at least one of the following: overvoltage abnormal state, overcurrent abnormal state, and short circuit abnormal state.

[0064] In this embodiment, the control unit determines whether there is an abnormal state in the power supply line through a first current signal, a first voltage signal, a second current signal, and a second voltage signal. In the case of an overvoltage abnormality, overvoltage is directly applied to the load (such as a chip, motor, or lighting equipment), far exceeding its rated insulation strength and withstand voltage limit. This can cause components (capacitors, switching devices) on the power supply line to undergo electrical breakdown due to overvoltage, resulting in permanent damage. Furthermore, the damage to one component may also generate surges on the power supply line or lead to further loss of control, affecting the safety of other equipment on the power supply line.

[0065] Overcurrent abnormalities can cause voltage drops in power supply lines, affecting the normal operation of equipment on the power supply lines. Secondly, continuous overcurrent can also increase heat loss of components on the power supply lines, which may be damaged due to overheating.

[0066] A short circuit may generate a large instantaneous current at the moment of the short circuit, producing a huge electromagnetic force (electrodynamic force) between parallel conductors. This may cause mechanical damage such as busbar deformation, switch contact explosion, and coil disintegration. It can also instantly drop the voltage of the entire local power grid, causing all equipment connected to the line to shut down, resulting in large-scale production interruption or system paralysis. Therefore, as long as the abnormal state includes any one of the following: overvoltage abnormality, overcurrent abnormality, or short circuit abnormality, it can be determined that there is an abnormality in the power supply line.

[0067] Step S173: In the event of an abnormal condition in the power supply line, the control switch unit disconnects the power supply line.

[0068] In this embodiment, when there is an abnormality in the power supply line, the control unit can send a control signal to the control terminal of the switch unit to physically disconnect the power supply line and achieve fault isolation.

[0069] In some embodiments, determining whether there is an abnormal state in the power supply line includes: If the first voltage signal and the second voltage signal exceed a preset voltage threshold, it is determined that the power supply line is in an overvoltage abnormal state; if the first current signal and the second current signal exceed a preset current threshold, it is determined that the power supply line is in an overcurrent abnormal state; if the first current signal and / or the second current signal exceed a short-circuit current threshold, it is determined that the power supply line is in a short-circuit abnormal state.

[0070] In this embodiment, the preset voltage threshold is the maximum voltage that the power supply line can withstand under normal operation. If the first voltage signal and the second voltage signal exceed the preset voltage threshold, an overvoltage anomaly is identified in the power supply line. In this case, the power supply line needs to be disconnected for further fault diagnosis. The preset current threshold is the maximum normal leakage current of the power supply line. If the current in both the first and second current signals exceeds the preset current threshold, an overcurrent anomaly is identified in the power supply line. This indicates an abnormal current leakage or shunting between the power supply and receiving ends of the power supply line, a key characteristic of insulation damage or a non-metallic short circuit. The short-circuit current threshold is the maximum short-circuit current that the power supply line can withstand. If the first current signal exceeds the short-circuit current threshold, a short-circuit anomaly is identified in the power supply line. If the second current signal exceeds the short-circuit current threshold, a short-circuit anomaly is identified in the power supply line. If both the first and second current signals exceed the short-circuit current threshold, a short-circuit anomaly is identified in the power supply line.

[0071] In addition, if the temperature of the switching unit exceeds the preset temperature, the power supply line will also be considered to be in an abnormal state.

[0072] Figure 18 This is a flowchart illustrating the steps of applying a solid-state switch to a power supply line according to an embodiment of this application. The following will refer to... Figure 18 ,as well as Figures 1-15 The working state of a solid-state switch applied to a power supply line according to this embodiment is described in detail.

[0073] Step S181: Check if there is an abnormality in the communication between the communication unit and the input / output control unit and the control unit. If yes, it means that the solid-state switch is in a fault state and the control signal is invalid, and proceed to the end; if no, proceed to step S182. Specifically, the solid-state switch is powered on, and the communication unit communicates with the control unit via CAN or RS485; the input / output control unit communicates with the control unit via IO signals, and it checks whether the transmission of control signals between the communication unit and the input / output control unit and the control unit is effective.

[0074] Step S182: Send a control signal to turn on the solid-state switch. Proceed to step S183.

[0075] Step S183: Check if the solid-state switch is operating normally, if there is an overvoltage abnormality, and if so, activate the overvoltage protection; if there is an overcurrent abnormality, and if so, activate the overcurrent protection; if there is a short-circuit current, and if so, activate the short-circuit protection; if there is a temperature abnormality, and if so, activate the over-temperature protection. If at least one of the above abnormalities exists, send a control signal and proceed to step S184. If no abnormality is found, maintain the current detection state.

[0076] Step S184: Disconnect the solid-state switch and cut off the power supply line.

[0077] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0078] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods and apparatus according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that instructions executable by the processor of the computer or other programmable data processing terminal device are configured to implement the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0079] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0080] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0081] The present invention has provided a detailed description of a switching circuit, a solid-state switch, and a detection method. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only intended to help understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A switching circuit, characterized by, The application relates to a switch circuit. The switch circuit comprises a switch unit, a first detection unit, a second detection unit and a control unit. The switch unit is connected in series on a power supply line and comprises a first connection end, a second connection end and a control end. The first connection end is electrically connected with a power supply end of the power supply line. The second connection end is electrically connected with a power receiving end of the power supply line.

2. The switching circuit of claim 1, wherein The first detection unit is electrically connected with the first connection end and is configured to collect a first voltage signal and a first current signal of the power supply end of the power supply line. The second detection unit is electrically connected with the second connection end and is configured to collect a second voltage signal and a second current signal of the power receiving end of the power supply line.

3. The switching circuit of claim 2, wherein The control unit is electrically connected with the first detection unit, the second detection unit and the control end respectively.

4. The switching circuit according to claim 2 or 3, characterized in that The control unit is configured to send a control signal to the control end to cut off the power supply line when it is determined that the power supply line has an abnormal state based on the first voltage signal, the first current signal, the second voltage signal and the second current signal.

5. The switching circuit of claim 2, wherein The switch unit comprises a first switch and a second switch. The first end of the first switch is electrically connected with the power supply end of the power supply line. The second end of the first switch is electrically connected with the second end of the second switch.

6. The switching circuit of claim 1, wherein The first end of the second switch is electrically connected with the power receiving end of the power supply line. The control end of the first switch and the control end of the second switch are electrically connected with the control unit respectively. The control unit is configured to send the control signal to the first switch and the second switch when the power supply line is abnormal. The switch unit further comprises a first capacitor, a second capacitor and an inductor. The first end of the first capacitor is electrically connected with the first end of the first switch. The first end of the second capacitor is electrically connected with the first end of the second switch. The second end of the first capacitor and the second end of the second capacitor are grounded. The first end of the inductor is electrically connected with the second end of the first switch. The second end of the inductor is electrically connected with the second end of the second switch. The switch unit further comprises a third switch and a fourth switch. The first end of the third switch is electrically connected with the second end of the first switch. The first end of the fourth switch is electrically connected with the second end of the second switch. The second end of the third switch and the second end of the fourth switch are grounded. The control end of the third switch and the control end of the fourth switch are electrically connected with the control unit. The switch circuit further comprises a temperature detection unit which is electrically connected with the control unit. The temperature detection unit is configured to detect the temperature of the first switch and the second switch. The control unit is further configured to send the control signal to the first switch and the second switch when the temperature exceeds a preset temperature threshold. The application further relates to a control system. The control system comprises a communication unit and an input-output control unit. The communication unit and the input-output control unit are electrically connected with the control unit through a communication interface respectively.

7. A solid state switch, characterized by The switch circuit comprises a shell, a heat sink and the switch circuit according to any one of claims 1-6; wherein the heat sink and the switch circuit are arranged inside the shell, and the switch unit is connected with the heat sink.

8. The solid state switch of claim 7, wherein, Further comprising: a main power interface, wherein the main power interface is arranged on a side wall of the shell, and the main power interface comprises an input positive copper bar, a negative copper bar and an output positive copper bar arranged side by side; wherein the input positive copper bar is electrically connected with a power supply end of a power supply line, the output positive copper bar is electrically connected with a power receiving end of the power supply line, and the negative copper bar is electrically connected with the power supply end and the power receiving end respectively.

9. A detection method of a switching circuit, characterized by, The control unit applied to the switch circuit according to any one of claims 1-6, the detection method comprising: obtaining a first current signal, a first voltage signal, a second current signal and a second voltage signal on a power supply line; determining whether the power supply line has an abnormal state based on the first voltage signal, the first current signal, the second voltage signal and the second current signal; wherein the abnormal state comprises at least one of an overvoltage abnormal state, an overcurrent abnormal state and a short-circuit abnormal state; controlling the switch unit to cut off the power supply line when the power supply line has an abnormal state.

10. The detection method according to claim 9, characterized in that, The determination of whether the power supply line has an abnormal state comprises: determining that the power supply line has an overvoltage abnormal state when the voltage of the first voltage signal and the second voltage signal exceeds a preset voltage threshold value; determining that the power supply line has an overcurrent abnormal state when the first current signal and the second current signal exceed a preset current threshold value; determining that the power supply line has a short-circuit abnormal state when the first current signal and / or the second current signal exceeds a short-circuit current threshold value.

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