SSR with hardware protection function

Abstract

The invention belongs to an aviation power distribution system, and relates to an SSR (Simple Sequence Repeat) with a hardware protection function, which comprises two load loop parameter acquisition circuits, a reference source circuit, a hardware overcurrent protection circuit, a hardware short-circuit protection circuit, an MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) driving circuit, a high-power load loop, two output isolation circuits and a power supply circuit. The load loop parameter acquisition circuit acquires the current of the power loop and outputs the current to the hardware over-current protection circuit and the hardware short-circuit protection circuit through the conditioning circuit; if the voltage conditioned and output by the load loop parameter acquisition circuit exceeds the reference voltage, the hardware over-current protection circuit performs thermal accumulation through a forward integrating circuit, and after the upper limit of thermal accumulation is exceeded, an over-current protection switch is triggered; if the voltage conditioned and output by the load loop parameter acquisition circuit exceeds the short-circuit protection level, the short-circuit protection switch is triggered. The control and protection of the high-power SSR are realized by a hardware circuit, and the switching safety of the bus bar of the airplane is improved.

Description

Technical Field

[0001] This invention pertains to aviation power distribution systems, specifically relating to a method for switching high-power busbars and hardware protection, which can be applied to the field of power control in power distribution systems. Background Technology

[0002] A solid-state relay (SSR) is a static relay composed entirely of solid-state electronic components such as semiconductor devices and passive components. It utilizes the switching characteristics of power semiconductor devices to control the connection and disconnection of circuits. SSRs can effectively improve the quality of uninterruptible power supply (UPS) for aircraft, further enhancing the reliability and safety of power busbar switching in advanced civil aircraft. Currently, conventional contactors or relays cannot achieve rapid switching of high-power busbars. This necessitates a new design to enable faster busbar switching when needed, meeting safety requirements; it also needs to consider providing overcurrent and short-circuit protection functions in the event of conventional control failure. Summary of the Invention

[0003] Purpose of the invention: To provide an SSR with hardware protection functions to improve the reliability and safety of power transfer from advanced civil aircraft power supply busbars.

[0004] Technical solution: An SSR with hardware protection includes: two load loop parameter acquisition circuits, a reference source circuit, a hardware overcurrent protection circuit, a hardware short-circuit protection circuit, a MOSFET drive circuit, a high-power load loop, two output isolation circuits, and a power supply circuit, wherein: The power supply circuit is used to supply power to the reference source circuit, the parameter acquisition circuits of the two load loops, the hardware overcurrent protection circuit, the hardware short circuit protection circuit, the MOSFET drive circuit, and the two output isolation circuits. The load circuit parameter acquisition circuit has two redundant circuits. The input of the two circuits is the voltage across the sampling resistor of the high-power load circuit. The output of one circuit is connected to the hardware overcurrent protection circuit, and the output of the other circuit is connected to the short circuit protection circuit. The 0.5V output voltage of the reference source circuit serves as the voltage reference for the hardware overcurrent protection circuit and is connected to the reference ground of the hardware overcurrent protection circuit. The input of the hardware overcurrent protection circuit is connected to the output of a load circuit parameter acquisition circuit, and the hardware overcurrent protection signal is output to the MOSFET drive circuit. The input of the short-circuit protection circuit is connected to the output of a load circuit parameter acquisition circuit, and outputs a hardware short-circuit protection signal to the MOSFET drive circuit. An output isolation circuit is used to isolate the external ground / on control signal and output it to the MOSFET drive circuit; Another output isolation circuit is used to isolate the output of the MOSFET drive circuit so that the output is in the load loop open state; The three input terminals of the MOSFET driver circuit receive the isolated control signal, the hardware overcurrent protection signal, and the hardware short-circuit protection signal, respectively. The output of the MOSFET driver circuit is connected to the control input of the high-power load circuit. The power input and output terminals of the high-power load circuit are connected to two external busbars, respectively.

[0005] Furthermore, the load circuit parameter acquisition circuit includes resistors and operational amplifiers, and the voltage signal is amplified through the resistor network and operational amplifiers.

[0006] Furthermore, the hardware overcurrent protection circuit includes: a positive integrator circuit and a comparator. The voltage value is integrated by the positive integrator circuit, and the output of the integrator circuit is connected to the inverting input terminal of the comparator circuit. The positive input terminal of the comparator is a resistor voltage divider network, and the output of the comparator circuit is connected to the AND gate in the MOSFET driver circuit.

[0007] Furthermore, the hardware short-circuit protection circuit includes a comparator. The inverting input of the comparator receives the output of the power loop parameter circuit, the non-inverting input of the comparator is a resistor divider network, and the output of the comparator circuit is connected to the AND gate in the MOSFET driver circuit.

[0008] Furthermore, the MOSFET driving circuit includes a three-input AND gate and a driving chip. The three inputs of the three-input AND gate are respectively isolated control signals, hardware overcurrent protection signals, and hardware short-circuit protection signals. The output of the three-input AND gate is connected to the input of the driving chip, and after being amplified by the driving chip, the output is connected to the gate of the MOSFET.

[0009] Furthermore, the control input of the high-power load circuit is connected to the output of the MOSFET drive circuit, the power input of the high-power load circuit is connected to the battery busbar, and the output of the high-power load circuit is connected to the external busbar.

[0010] Furthermore, when the current in the load circuit is less than or equal to 1.2 times the rated current, both the hardware overcurrent protection circuit and the hardware short-circuit protection circuit output a high level. When the load circuit current is greater than 1.2 times the rated current but less than 10 times the rated current, the hardware overcurrent protection circuit performs thermal accumulation through the positive integrator circuit. When the thermal accumulation reaches the upper limit, it outputs a low level to the AND gate. The AND gate outputs a level drive signal to the drive circuit. After receiving the low-level drive signal, the drive circuit outputs a high-power load circuit turn-off signal to turn off the high-power load circuit. The hardware short-circuit protection circuit does not function and outputs a high level. When the load circuit current is greater than or equal to 10 times the rated current, the short-circuit protection circuit outputs a low level to the AND gate through the comparator. The AND gate outputs a level drive signal to the drive circuit. After receiving the low-level drive signal, the drive circuit outputs a high-power load circuit turn-off signal to turn off the high-power load circuit. The action time of the hardware short-circuit protection circuit is shorter than that of the hardware overcurrent protection circuit.

[0011] Furthermore, the high-power load circuit includes: multiple MOSFETs connected in parallel and a high-power diode, wherein the anode of the high-power diode is connected to the source of the MOSFET, the cathode of the high-power diode is connected to other return bars, and the number of MOSFETs is determined according to the charging current of the bus bar.

[0012] Furthermore, the driver chip is MIC4416YM4.

[0013] Furthermore, the output isolation circuit achieves isolation through an optocoupler.

[0014] Beneficial effects: This invention designs a high-power relay using discrete components such as resistors, capacitors, operational amplifiers, and MOSFETs. It features fast switching action, low on-state voltage, and can achieve overcurrent and short-circuit protection without relying on software. It also boasts strong anti-interference capabilities, low external interference, long lifespan, and high operational reliability. This easy-to-implement and highly reliable control method ensures that there will be no power outage during aircraft busbar switching, while also possessing autonomous protection functions, thus improving the safety of aircraft busbar switching. Attached Figure Description

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

[0016] Figure 1 This is a schematic diagram of the SSR with hardware protection function of the present invention.

[0017] Figure 2 This is a block diagram of a hardware overcurrent protection circuit.

[0018] Figure 3 This is a block diagram of a hardware short-circuit protection circuit. Detailed Implementation

[0019] 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 only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0021] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] This invention relates to an SSR with hardware protection, comprising: two load loop parameter acquisition circuits, a reference source circuit, a hardware overcurrent protection circuit, a hardware short-circuit protection circuit, a MOSFET drive circuit, a high-power load loop, two output isolation circuits, and a power supply circuit. The load loop parameter acquisition circuits acquire the current of the power loop and output it to the hardware overcurrent protection circuit and hardware short-circuit protection circuit through a conditioning circuit. The reference source circuit provides a stable voltage reference, raising the reference voltage of the hardware overcurrent protection circuit as a lower limit for thermal accumulation. If the voltage conditioned by the load loop parameter acquisition circuit exceeds the reference voltage, the hardware overcurrent protection circuit performs thermal accumulation through a positive integrator circuit. If the thermal accumulation exceeds the upper limit, the overcurrent protection switch is triggered, and the drive signal is invalidated. If the voltage conditioned by the load loop parameter acquisition circuit exceeds the short-circuit protection level, the short-circuit protection switch is triggered, and the drive signal is invalidated. This invention achieves control and protection of a high-power SSR through hardware circuitry, improving the safety of aircraft busbar switching.

[0025] An SSR with hardware protection includes: two load loop parameter acquisition circuits, a reference source circuit, a hardware overcurrent protection circuit, a hardware short-circuit protection circuit, a MOSFET drive circuit, a high-power load loop, two output isolation circuits, and a power supply circuit, wherein: The power supply circuit is used to supply power to the reference source circuit, the parameter acquisition circuits of the two load loops, the hardware overcurrent protection circuit, the hardware short circuit protection circuit, the MOSFET drive circuit, and the two output isolation circuits. The load circuit parameter acquisition circuit has two redundant circuits. The input of the two circuits is the voltage across the sampling resistor of the high-power load circuit. The output of one circuit is connected to the hardware overcurrent protection circuit, and the output of the other circuit is connected to the short circuit protection circuit. The 0.5V output voltage of the reference source circuit serves as the voltage reference for the hardware overcurrent protection circuit and is connected to the reference ground of the hardware overcurrent protection circuit. The input of the hardware overcurrent protection circuit is connected to the output of a load circuit parameter acquisition circuit, and the hardware overcurrent protection signal is output to the MOSFET drive circuit. The input of the short-circuit protection circuit is connected to the output of a load circuit parameter acquisition circuit, and outputs a hardware short-circuit protection signal to the MOSFET drive circuit. An output isolation circuit is used to isolate the external ground / on control signal and output it to the MOSFET drive circuit; Another output isolation circuit is used to isolate the output of the MOSFET drive circuit so that the output is in the load loop open state; The three input terminals of the MOSFET driver circuit receive the isolated control signal, the hardware overcurrent protection signal, and the hardware short-circuit protection signal, respectively. The output of the MOSFET driver circuit is connected to the control input of the high-power load circuit. The power input and output terminals of the high-power load circuit are connected to two external busbars, respectively.

[0026] Furthermore, the load circuit parameter acquisition circuit includes resistors and operational amplifiers, and the voltage signal is amplified through the resistor network and operational amplifiers.

[0027] Furthermore, the hardware overcurrent protection circuit includes: a positive integrator circuit and a comparator. The voltage value is integrated by the positive integrator circuit, and the output of the integrator circuit is connected to the inverting input terminal of the comparator circuit. The positive input terminal of the comparator is a resistor voltage divider network, and the output of the comparator circuit is connected to the AND gate in the MOSFET driver circuit.

[0028] Furthermore, the hardware short-circuit protection circuit includes a comparator. The inverting input of the comparator receives the output of the power loop parameter circuit, the non-inverting input of the comparator is a resistor divider network, and the output of the comparator circuit is connected to the AND gate in the MOSFET driver circuit.

[0029] Furthermore, the MOSFET driving circuit includes a three-input AND gate and a driving chip. The three inputs of the three-input AND gate are respectively isolated control signals, hardware overcurrent protection signals, and hardware short-circuit protection signals. The output of the three-input AND gate is connected to the input of the driving chip, and after being amplified by the driving chip, the output is connected to the gate of the MOSFET.

[0030] Furthermore, the control input of the high-power load circuit is connected to the output of the MOSFET drive circuit, the power input of the high-power load circuit is connected to the battery busbar, and the output of the high-power load circuit is connected to the external busbar.

[0031] Furthermore, when the current in the load circuit is less than or equal to 1.2 times the rated current, both the hardware overcurrent protection circuit and the hardware short-circuit protection circuit output a high level. When the load circuit current is greater than 1.2 times the rated current but less than 10 times the rated current, the hardware overcurrent protection circuit performs thermal accumulation through the positive integrator circuit. When the thermal accumulation reaches the upper limit, it outputs a low level to the AND gate. The AND gate outputs a level drive signal to the drive circuit. After receiving the low-level drive signal, the drive circuit outputs a high-power load circuit turn-off signal to turn off the high-power load circuit. The hardware short-circuit protection circuit does not function and outputs a high level. When the load circuit current is greater than or equal to 10 times the rated current, the short-circuit protection circuit outputs a low level to the AND gate through the comparator. The AND gate outputs a level drive signal to the drive circuit. After receiving the low-level drive signal, the drive circuit outputs a high-power load circuit turn-off signal to turn off the high-power load circuit. The action time of the hardware short-circuit protection circuit is shorter than that of the hardware overcurrent protection circuit.

[0032] Furthermore, the high-power load circuit includes: multiple MOSFETs connected in parallel and a high-power diode, wherein the anode of the high-power diode is connected to the source of the MOSFET, the cathode of the high-power diode is connected to other return bars, and the number of MOSFETs is determined according to the charging current of the bus bar.

[0033] Furthermore, the driver chip is MIC4416YM4.

[0034] Furthermore, the output isolation circuit achieves isolation through an optocoupler.

[0035] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0036] Currently, switching of aircraft power supply buses is typically achieved via contactors, which is slow and can cause voltage drops in the busbars during switching, potentially leading to malfunctions in some electrical equipment and impacting aircraft safety. This paper designs a high-power SSR that can briefly provide battery power to the busbars during switching. The SSR is software-independent, offers fast switching speeds, and features independent overcurrent and short-circuit protection, thus improving safety during aircraft busbar switching.

[0037] SSR functions are divided into power supply, control, communication, and protection functions. The power supply function is a prerequisite for SSR operation and the realization of its intended functions. It preprocesses external power supplies, ensuring safe and reliable power supply to the various functional units within the SSR. The control function accepts and executes external "ground / on" control commands. When the external discrete control signal is "ground," it is an "on" command; when the external control signal is "on," it is a "off" command. The protection function includes hardware overcurrent protection and hardware short-circuit protection. The communication function enables communication between the SSR and external systems, primarily providing SSR status feedback using "ground / on" signals to indicate the SSR's status.

[0038] Figure 1 The power supply circuit converts the external battery power supply into an internal usable voltage.

[0039] Figure 1The control signal for the external discrete quantity is converted from a ground / on signal to a high / ground signal after passing through the isolation chip. The high signal represents an on command. The isolation chip outputs a drive signal to an AND gate. The AND gate performs logic output based on three inputs: the external discrete quantity drive input, the hardware overcurrent protection signal, and the short-circuit protection signal. Only when all three signals are high can the AND gate output a high level to the drive circuit. Upon receiving the high-level drive signal, the drive circuit outputs an on signal for the high-power load circuit, driving the high-power load circuit to conduct. This enables power supply between different busbars. The drive signal is output to other devices through the isolation chip, providing information for SSR on or off.

[0040] Figure 1 The load circuit parameter acquisition circuit, reference source circuit, hardware overcurrent protection circuit, and hardware short-circuit protection circuit work together to achieve hardware overcurrent and short-circuit protection. The 0.5V output of the reference source circuit serves as the voltage reference for the hardware overcurrent protection circuit and as the lower limit of the hardware overcurrent protection function integrator circuit. When the load circuit current is less than or equal to 1.2 times the rated current, both the overcurrent protection circuit and the short-circuit protection circuit output a high level. When the load circuit current is greater than 1.2 times the rated current but less than 10 times the rated current, the hardware overcurrent protection circuit performs thermal accumulation through the positive integrator circuit. When the thermal accumulation reaches the upper limit, it outputs a low level to the AND gate. The AND gate outputs a level drive signal to the drive circuit. Upon receiving the low-level drive signal, the drive circuit outputs a high-power load circuit shutdown signal, shutting down the high-power load circuit. When the load circuit current is greater than or equal to 10 times the rated current, the short-circuit protection circuit outputs a low level through a comparator to the AND gate. The AND gate outputs a level drive signal to the drive circuit. Upon receiving the low-level drive signal, the drive circuit outputs a high-power load circuit shutdown signal, shutting down the high-power load circuit.

[0041] Figure 1 The medium-to-high power load circuit consists of multiple MOSFETs and high-power diodes. The MOSFETs can be quickly turned on and off according to the drive signal. Compared with traditional contactors, the power circuit has a fast response speed, no contacts, no electric arc, no noise, and low electromagnetic interference. The high-power diodes in the circuit can interrupt the power supply circuit from the busbar to the battery busbar.

[0042] Figure 2This is a block diagram of a hardware overcurrent protection circuit. In the diagram, one end of R2 is connected to the output of the load circuit parameter acquisition circuit, and the other end is connected to the positive input of operational amplifier V1; one end of C1 is connected to the positive input of operational amplifier V1, and the other end is connected to the reference voltage Vref; one end of R1 is connected to the reference voltage Vref, and the other end is connected to the inverting input of V1; one end of C2 is connected to the inverting input of V1, and the other end is connected to the output of V1; the output of V1 is connected to the inverting input of the operational amplifier; one end of R3 is connected to the power supply, and the other end is connected to the positive input of V2; one end of R4 is connected to the positive output of V2, and the other end is connected to ground; C3 and C4 are decoupling capacitors for the chip's power supply, connected to the chip's power supply pin and ground respectively; the output of V2 serves as the output of the MOSFET driver circuit.

[0043] When the current in the load circuit is less than or equal to 1.2 times the rated current, Figure 2 Vin is less than Vref. Figure 2 The output of V1 is less than 0V; when the load circuit current is greater than 1.2 times the rated current but less than 10 times the rated current, Figure 2 When Vin is greater than Vref, the output voltage of V1 increases over time. Figure 2 The higher the voltage of Vin, the faster the output voltage of V1 changes. When the output voltage of V1 is greater than the positive input voltage of V2, V2 outputs a low level, and after logic processing with other control signals, the MOSFET is turned off.

[0044] Figure 3 This is a block diagram of a hardware short-circuit protection circuit. One end of R5 is connected to the power supply, and the other end is connected to the positive input of operational amplifier V2. One end of R6 is connected to the positive output of V3, and the other end is connected to reference ground. C5 is a decoupling capacitor for the chip's power supply, connected to both the chip's power supply pin and reference ground. The output of V2 serves as the output of the MOSFET driver circuit. Vin is connected to the output of the load circuit parameter acquisition circuit. When the load circuit current is less than 10 times the rated current, the voltage of Vin is less than the voltage at the positive input of V3, and V3 outputs a high level. When the load circuit current is greater than or equal to 10 times the rated current, the voltage of Vin is greater than the voltage at the positive input of V3, and V3 outputs a low level. After logic processing with other control signals, the MOSFET is turned off.

[0045] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A SSR with hardware protection function, characterized in that, The SSR with hardware protection function comprises: two load loop parameter acquisition circuits, a reference source circuit, a hardware overcurrent protection circuit, a hardware short circuit protection circuit, a MOSFET drive circuit, a high-power load loop, two output isolation circuits, and a power supply circuit, wherein: the power supply circuit is used for supplying power to the reference source circuit, the two load loop parameter acquisition circuits, the hardware overcurrent protection circuit, the hardware short circuit protection circuit, the MOSFET drive circuit, and the two output isolation circuits; the two sets of redundant load loop parameter acquisition circuits have inputs of voltages across sampling resistors of the high-power load loop, an output of one set of the circuits is connected to the hardware overcurrent protection circuit, and an output of the other set of the circuits is connected to the short circuit protection circuit; the output 0.5V voltage of the reference source circuit is used as a voltage reference of the hardware overcurrent protection circuit and is connected to a reference ground of the hardware overcurrent protection circuit; the input of the hardware overcurrent protection circuit is connected to the output of one set of the load loop parameter acquisition circuits, and the hardware overcurrent protection circuit outputs a hardware overcurrent protection signal to the MOSFET drive circuit; the input of the short circuit protection circuit is connected to the output of one set of the load loop parameter acquisition circuits, and the short circuit protection circuit outputs a hardware short circuit protection signal to the MOSFET drive circuit; one output isolation circuit is used for isolating and outputting external ground / open control signals to the MOSFET drive circuit; the other output isolation circuit is used for isolating and outputting the output of the MOSFET drive circuit to a load loop open state; the three inputs of the MOSFET drive circuit receive the isolated control signals, the hardware overcurrent protection signal, and the hardware short circuit protection signal, respectively, and the output of the MOSFET drive circuit is connected to the control input of the high-power load loop; the power input and the output of the high-power load loop are connected to two external bus bars, respectively.

2. The SSR with hardware protection function according to claim 1, characterized in that, The load loop parameter acquisition circuit comprises resistors and operational amplifiers, and the voltage signal is amplified through the resistor network and the operational amplifiers.

3. The SSR with hardware protection function according to claim 1, characterized in that, The hardware overcurrent protection circuit comprises a positive integration circuit and a comparator, the voltage value is integrated through the positive integration circuit, the output of the integration circuit is connected to the reverse input end of the comparator circuit, the positive input end of the comparator is a resistor voltage dividing network, and the output of the comparator circuit is connected to the AND gate in the MOSFET drive circuit.

4. The SSR with hardware protection function according to claim 1, characterized in that, The hardware short circuit protection circuit comprises a comparator, the reverse input end of the comparator receives the output of the power loop parameter circuit, the positive input end of the comparator is a resistor voltage dividing network, and the output of the comparator circuit is connected to the AND gate in the MOSFET drive circuit.

5. The SSR with hardware protection function according to claim 1, characterized in that, The MOSFET drive circuit comprises a three-input AND gate and a drive chip, the three inputs of the three-input AND gate are the isolated control signals, the hardware overcurrent protection signal, and the hardware short circuit protection signal, respectively, the output end of the three-input AND gate is connected to the input end of the drive chip, the output connected to the gate of the MOSFET after being amplified by the drive chip.

6. The SSR with hardware protection function according to claim 1, characterized in that, The control input of the high-power load loop is connected to the output of the MOSFET drive circuit, the power input of the high-power load loop is connected to the battery bus bar, and the output of the high-power load loop is connected to the external bus bar.

7. The SSR with hardware protection function according to claim 1, wherein When the current of the load circuit is less than or equal to 1.2 times of the rated current, both the hardware overcurrent protection circuit and the hardware short-circuit protection circuit output high level; When the current of the load circuit is greater than 1.2 times of the rated current and less than 10 times of the rated current, the hardware overcurrent protection circuit performs thermal accumulation through a positive integral circuit, and when the thermal accumulation reaches an upper limit, a low level is output to an AND gate, the AND gate outputs a level driving signal to a driving circuit, the driving circuit outputs a high-power load circuit shutdown signal after receiving the low-level driving signal, and the high-power load circuit is shut down; the hardware short-circuit protection circuit does not work and outputs high level; When the current of the load circuit is greater than or equal to 10 times of the rated current, the short-circuit protection circuit outputs a low level to the AND gate through a comparator, the AND gate outputs a level driving signal to the driving circuit, the driving circuit outputs a high-power load circuit shutdown signal after receiving the low-level driving signal, and the high-power load circuit is shut down; the action time of the hardware short-circuit protection circuit is less than that of the hardware overcurrent protection circuit.

8. The SSR with hardware protection function according to claim 1, characterized in that, The high-power load circuit comprises a plurality of parallel MOSFETs and a high-power diode, wherein the anode of the high-power diode is connected with the source of the MOSFET, the cathode of the high-power diode is connected with other return strips, and the number of the MOSFETs is determined according to the charging current of the bus bar.

9. The SSR with hardware protection function according to claim 1, characterized in that, The driving chip is MIC4416YM4.

10. The SSR with hardware protection function according to claim 1, characterized in that, The output isolation circuit realizes isolation through an optical coupler.

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