Direct current SSPC current limiting control system and control method thereof

Abstract

The invention discloses a direct current SSPC current limiting control system and a control method thereof, and relates to the field of power electronics and electricians. The RC network generates a control voltage according to the switch control signal; the driving power amplification circuit carries out power amplification processing on the control voltage; the main power circuit conducts or cuts off the branch power distribution channel according to the processed voltage so as to provide a current path; the current-limiting state judgment circuit judges whether to enter or exit a current-limiting state according to information data fed back by the feedback circuit, and outputs a signal to the current closed-loop current-limiting control circuit; and the current closed-loop current-limiting control circuit receives the signal output by the current-limiting state judgment circuit and adjusts a control voltage corresponding to a main branch power tube in the RC network according to the SSPC channel current so as to realize constant-current control of the power distribution channel. The invention aims to improve the stability and thermal reliability of direct current SSPC current-limiting control.

Description

Technical Field

[0001] The present application relates to the fields of power electronics and electrical engineering, and particularly to a DC SSPC current-limiting control system and its control method. Background Art

[0002] A Solid State Power Controller (SSPC) is an intelligent power distribution device with a power semiconductor as its core, integrating the switch control function of a relay and the fault protection function of a circuit breaker. As the core component of an aircraft solid-state power distribution system, the SSPC has the advantages of no contacts, no arc, no noise, rapid response, low electromagnetic interference, long service life, high reliability, and convenient computer remote control. Therefore, it is widely used in fields such as aircraft, tanks, ships, and civilian power distribution networks.

[0003] With the development trend of high voltage and DC in more-electric / all-electric aircraft, the number of capacitive loads in the power distribution system gradually increases, which poses new requirements for the DC SSPC to quickly and reliably connect large capacitive loads. However, due to the characteristic that the capacitor voltage cannot change suddenly, the power distribution system will generate inrush current when starting or suddenly adding capacitive loads, which is extremely likely to cause misoperation of the SSPC fault protection, thus affecting the normal operation of the power distribution system and even causing equipment such as the SSPC and load to burn out.

[0004] Currently, the current-limiting control methods for suppressing the inrush current when the DC SSPC connects capacitive loads are mainly divided into the power electronics current-limiting method and the current-limiting branch method. The power electronics current-limiting method uses power semiconductor devices as current-limiting devices. For example, by controlling the driving voltage of the power semiconductor device to change slowly so that it operates in the saturation region, it can better suppress the current stress when the DC SSPC connects capacitive loads. However, due to the limitation of the heat capacity of the power semiconductor device, the MOSFET of the SSPC is prone to thermal failure when quickly connecting large capacitive loads.

[0005] The current-limiting branch method uses a current-limiting resistor as a current-limiting device. For example, the current-limiting resistor is used to pre-charge the large capacitive load. When the capacitor voltage approaches the bus voltage, the main branch is switched in to bypass the current-limiting resistor, thereby completing the connection of the capacitive load. However, as the voltage level increases and the load capacitor capacity increases, the time required for pre-charging the load capacitor becomes longer; under the condition of resistive-capacitive load, due to the voltage-dividing effect of the current-limiting resistor, the secondary inrush current is large when the main branch is switched in; and the heat capacity of the power device is not fully utilized, resulting in an increase in the volume, weight, and cost of the SSPC. Therefore, the current traditional DC SSPC current-limiting control methods cannot achieve quick connection of large capacitive loads.

[0006] In addition, in the current research, a multi-segment current limiting control method for DC SSPC is proposed by combining voltage and current double closed-loop control and a current limiting branch. To a certain extent, this method can achieve rapid connection of large capacitive loads, but it has the disadvantages of complex control, difficult tuning of control parameters, susceptibility to interference, and poor practicability.

[0007] Therefore, there is an urgent need to study a current limiting control method for DC SSPC that can reliably and quickly connect large capacitive loads. Summary of the Invention

[0008] The purpose of this application is to provide a current limiting control system and its control method for DC SSPC, which can improve the stability and thermal reliability of current limiting control for DC SSPC.

[0009] To achieve the above purpose, this application provides the following solutions:

[0010] In the first aspect, this application provides a current limiting control system for DC SSPC, including: a main power circuit, an RC network, a drive power amplifier circuit, a feedback circuit, a current limiting state judgment circuit, and a current closed-loop current limiting control circuit;

[0011] The main power circuit is respectively connected to the drive power amplifier circuit and the feedback circuit; the RC network is connected to the drive power amplifier circuit; the current limiting state judgment circuit is connected to the feedback circuit; the current closed-loop current limiting control circuit is respectively connected to the current limiting state judgment circuit, the feedback circuit, and the RC network;

[0012] The RC network is used to generate a control voltage according to the switch control signal;

[0013] The drive power amplifier circuit is used to perform power amplification processing on the control voltage to obtain the processed voltage;

[0014] The main power circuit is used to conduct or cut off the branch power distribution channel according to the processed voltage to provide a current path;

[0015] The feedback circuit is used to obtain information data and feedback it to the current limiting state judgment circuit and the current closed-loop current limiting control circuit; the information data includes: SSPC channel current, load voltage, and SSPC input voltage; the SSPC channel current is the output current of the main power circuit; the SSPC input voltage is the input voltage of the main power circuit;

[0016] The current limiting state judgment circuit is used to judge whether to enter or exit the current limiting state according to the information data and output a signal to the current closed-loop current limiting control circuit;

[0017] The current closed-loop current limiting control circuit is used to receive the signal output by the current limiting state judgment circuit and adjust the control voltage corresponding to the main branch power tube in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel.

[0018] In a second aspect, the present application provides a control method for a DC SSPC current-limiting control system, and the method is implemented by using the DC SSPC current-limiting control system described above. The control method of the DC SSPC current-limiting control system includes:

[0019] Obtain a switch control signal and generate a control voltage according to the switch control signal;

[0020] Perform power amplification processing on the control voltage to obtain a processed voltage;

[0021] Conduct or cut off the branch power distribution channel according to the processed voltage to provide a current path;

[0022] Determine corresponding information data based on the current path. The information data includes: SSPC channel current, load voltage, and SSPC input voltage. The SSPC channel current is the output current of the main power circuit, and the SSPC input voltage is the input voltage of the main power circuit;

[0023] Judge whether to enter or exit the current-limiting state according to the information data, and output a signal to the current closed-loop current-limiting control circuit, and adjust the control voltage corresponding to the main branch power transistor in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel.

[0024] According to the specific embodiments provided by the present application, the present application has the following technical effects:

[0025] The present application provides a DC SSPC current-limiting control system and its control method. The RC network generates a control voltage according to a switch control signal; the drive power amplification circuit performs power amplification processing on the control voltage; the main power circuit conducts or shuts off the branch power distribution channel according to the processed voltage to provide a current path; the current-limiting state judgment circuit judges whether to enter or exit the current-limiting state according to the information data fed back by the feedback circuit and outputs a signal to the current closed-loop current-limiting control circuit; the current closed-loop current-limiting control circuit receives the signal output by the current-limiting state judgment circuit and adjusts the control voltage corresponding to the main branch power transistor in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel. The present application realizes effective suppression of inrush current by combining the main power circuit with the RC network and the current closed-loop current-limiting control circuit to control the working state in stages. When the current-limiting state judgment circuit detects that the inrush current enters the current-limiting state, it shuts off under the action of the current closed-loop current-limiting control circuit. As the inrush current decreases, the system charges the load capacitor with a constant current. Therefore, the SSPC current-limiting control time changes adaptively with the load. During the current-limiting process, the main power circuit commutates naturally and the thermal stress of the power devices is reasonably distributed, improving the control stability and thermal reliability. Thus, the present application improves the stability and thermal reliability of the DC SSPC current-limiting control. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic block diagram of the DC SSPC current-limiting control system of the present application;

[0028] Figure 2 It is a circuit diagram corresponding to the first part of the circuit in the embodiment of the present application;

[0029] Figure 3 It is a circuit diagram corresponding to the second part of the circuit in the embodiment of the present application;

[0030] Figure 4 It is a working timing diagram of the embodiment of the present application when starting a large pure capacitor load.

[0031] Reference numerals: First triode - T1, second triode - T2, first diode - D1, second diode - D2, first capacitor - C1, first resistor - R1, second resistor - R2, third resistor - R3, fourth resistor - R4, fifth resistor - R5, third triode - T3, fourth triode - T4, third diode - D3, fourth diode - D4, second capacitor - C2, sixth resistor - R6, seventh resistor - R7, eighth resistor - R8, ninth resistor - R9, tenth resistor - R 10 , fifth triode - T5, sixth triode - T6, seventh triode - T7, eighth triode - T8, sense resistor - R sense , first operational amplifier - OP1, second operational amplifier - OP2, N-channel depletion-mode power transistor - S1, fifth diode - D5, third capacitor - C3, eleventh resistor - R 11 , twelfth resistor - R 12 , thirteenth resistor - R 13 , fourteenth resistor - R 14 , fifteenth resistor - R 15 , sixteenth resistor - R 16 , seventeenth resistor - R 17 , eighteenth resistor - R 18 , reverse SR latch - U1, AND gate - AND1, first comparator - CMP1, second comparator - CMP2, ninth triode - T9, nineteenth resistor - R 19 , twentieth resistor - R 20 , twenty-first resistor - R 21 , twenty-second resistor - R 22 , twenty-third resistor - R 23 , twenty-fourth resistor - R 24 , twenty-fifth resistor - R 25 , twenty-sixth resistor - R 26 , first power transistor - Q1, second power transistor - Q2, current-limiting resistor - R Limit , twenty-seventh resistor - R 27 , twenty-eighth resistor - R 28 , twenty-ninth resistor - R 29 , thirtieth resistor - R 30 , third operational amplifier - OP3, thirty-first resistor - R 31 , thirty-second resistor - R 32 , thirty-third resistor - R 33 , thirty-fourth resistor - R 34 , fourth operational amplifier - OP4, thirty-fifth resistor - R 35 , thirty-sixth resistor - R 36 , thirty-seventh resistor - R 37 , thirty-eighth resistor - R38 , the fifth operational amplifier - OP5, drain - D, source - S, gate - G, DC voltage source - VCC. Detailed implementation

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0033] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the drawings and specific implementation manners.

[0034] In an exemplary embodiment, a DC SSPC current - limiting control system is provided, including: a main power circuit, an RC network, a drive power amplification circuit, a feedback circuit, a current - limiting state judgment circuit, and a current - closed - loop current - limiting control circuit.

[0035] The main power circuit is respectively connected to the drive power amplification circuit and the feedback circuit; the RC network is connected to the drive power amplification circuit; the current - limiting state judgment circuit is connected to the feedback circuit; the current - closed - loop current - limiting control circuit is respectively connected to the current - limiting state judgment circuit, the feedback circuit, and the RC network.

[0036] Specifically, the circuit diagram of the DC SSPC current - limiting control system is as Figures 1-3 shown.

[0037] The RC network is used to generate a control voltage according to a switch control signal. The RC network includes: a main - branch RC network and a current - limiting - branch RC network.

[0038] The main - branch RC network and the current - limiting - branch RC network are in parallel and are both connected to the drive power amplification circuit.

[0039] Among them, the main - branch RC network includes the first triode T1, the second triode T2, the first diode D1, the second diode D2, the first capacitor C1, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5.

[0040] The current - limiting - branch RC network includes the third triode T3, the fourth triode T4, the third diode - D3, the fourth diode D4, the second capacitor C2, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R 10 .

[0041] One end of the first resistor R1 is connected to the base of the first triode T1; the emitter of the first triode T1 is grounded; the collector of the first triode T1 is respectively connected to the base of the second triode T2 and the first terminal of the second resistor R2; the second terminal of the second resistor R2 and the first terminal of the third resistor R3 are both connected to the DC voltage source VCC; the collector of the second triode T2 is respectively connected to the second terminal of the third resistor R3, the anode of the first diode D1 and the cathode of the second diode D2; the cathode of the first diode D1 is connected to the first terminal of the fourth resistor R4; the anode of the second diode D2 is connected to the first terminal of the fifth resistor R5; the second terminal of the fourth resistor R4 is connected to the second terminal of the fifth resistor R5, and the second terminal of the fifth resistor R5 is connected to the first terminal of the first capacitor C1; the second terminal of the fourth resistor R4, the second terminal of the fifth resistor R5 and the first terminal of the first capacitor C1 are also all connected to the drive power amplification circuit; the emitter of the second triode T2 is grounded; the second terminal of the first capacitor C1 is grounded.

[0042] One end of the sixth resistor R6 is connected to the other end of the first resistor R1; the other end of the sixth resistor R6 is connected to the base of the third triode T3; the emitter of the third triode T3 is grounded; the collector of the third triode T3 is respectively connected to the base of the fourth triode T4 and the first terminal of the seventh resistor R7; the emitter of the fourth triode T4 is grounded; the collector of the fourth triode T4 is respectively connected to the second terminal of the eighth resistor R8, the anode of the third diode D3 and the cathode of the fourth diode D4; the second terminal of the seventh resistor R7 and the first terminal of the eighth resistor R8 are both connected to the DC voltage source VCC.

[0043] The cathode of the third diode D3 is connected to the first terminal of the ninth resistor R9; the anode of the fourth diode D4 is connected to the first terminal of the tenth resistor R 10 ; the second terminal of the ninth resistor R9 is connected to the second terminal of the tenth resistor R 10 ; and the second terminal of the tenth resistor R 10 is connected to the first terminal of the second capacitor C2; the second terminal of the ninth resistor R9, the second terminal of the tenth resistor R 10 and the first terminal of the second capacitor C2 are also all connected to the drive power amplification circuit; the second terminal of the second capacitor C2 is grounded.

[0044] The drive power amplification circuit is used to perform power amplification processing on the control voltage to obtain the processed voltage.

[0045] The drive power amplification circuit includes: a main branch drive power amplification circuit and a current limiting branch drive power amplification circuit.

[0046] The main branch drive power amplification circuit includes the fifth triode T5 and the sixth triode T6; the current-limiting branch drive power amplification circuit includes the seventh triode T7 and the eighth triode T8.

[0047] The collector of the fifth triode T5 is connected to the DC voltage source VCC; the base of the fifth triode T5 is connected to the base of the sixth triode T6, and both are connected to the main branch RC network.

[0048] The emitter of the fifth triode T5 is connected to the emitter of the sixth triode T6, and both are connected to the gate G of the first power transistor Q1; the collector of the sixth triode T6 is grounded.

[0049] The collector of the seventh triode T7 is connected to the DC voltage source VCC; the base of the seventh triode T7 is connected to the base of the eighth triode T8, and both are connected to the current-limiting branch RC network.

[0050] The emitter of the seventh triode T7 is connected to the emitter of the eighth triode T8, and both are connected to the gate G of the second power transistor Q2; the collector of the eighth triode T8 is grounded.

[0051] The main power circuit is used to conduct or cut off the branch power distribution channel according to the processed voltage to provide a current path.

[0052] The main power circuit includes: a main branch, a current-limiting branch, and a detection resistor R sense ; the main branch is in parallel with the current-limiting branch, and after being in parallel, it is in series with the detection resistor; among them, the main branch includes: the first power transistor Q1; the current-limiting branch includes: the second power transistor Q2 and the current-limiting resistor R Limit .

[0053] The source S of the first power transistor Q1 is connected to the source S of the second power transistor Q2; the drain D of the second power transistor Q2 is connected to the first terminal of the current-limiting resistor R Limit ; the drain D of the first power transistor Q1 is connected to the second terminal of the current-limiting resistor R Limit .

[0054] The feedback circuit is used to obtain information data and feedback it to the current-limiting state judgment circuit and the current closed-loop current-limiting control circuit; the information data includes: the SSPC channel current, the load voltage, and the SSPC input voltage; the SSPC channel current is the output current of the main power circuit; the SSPC input voltage is the input voltage of the main power circuit.

[0055] The feedback circuit includes: a current feedback circuit, a load voltage feedback circuit, and a power supply voltage feedback circuit.

[0056] Among them, the current feedback circuit includes: the twenty-seventh resistor R 27 , the twenty-eighth resistor R 28, the twenty-ninth resistor R 29 , the thirtieth resistor R 30 and the third operational amplifier OP3.

[0057] The load voltage feedback circuit includes: the thirty-first resistor R 31 , the thirty-second resistor R 32 , the thirty-third resistor R 33 , the thirty-fourth resistor R 34 and the fourth operational amplifier OP4.

[0058] The power supply voltage feedback circuit includes: the thirty-fifth resistor R 35 , the thirty-sixth resistor R 36 , the thirty-seventh resistor R 37 , the thirty-eighth resistor R 38 and the fifth operational amplifier OP5.

[0059] The first terminal of the twenty-seventh resistor R 27 is grounded; the second terminal of the twenty-seventh resistor R 27 is respectively connected to the non-inverting input terminal of the third operational amplifier OP3 and the first terminal of the twenty-eighth resistor R 28 ; the second terminal of the twenty-eighth resistor R 28 is connected to the main power circuit.

[0060] The first terminal of the twenty-ninth resistor R 29 is respectively connected to the inverting input terminal of the third operational amplifier OP3 and the first terminal of the thirtieth resistor R 30 ; the second terminal of the thirtieth resistor R 30 is connected to the output terminal of the third operational amplifier OP3; the second terminal of the twenty-ninth resistor R 29 is connected to the main power circuit.

[0061] The first terminal of the thirty-first resistor R 31 is grounded; the second terminal of the thirty-first resistor R 31 is respectively connected to the non-inverting input terminal of the fourth operational amplifier OP4 and the first terminal of the thirty-second resistor R 32 ; the second terminal of the thirty-second resistor R 32 is connected to the main power circuit.

[0062] The first terminal of the thirty-third resistor R 33 is respectively connected to the inverting input terminal of the fourth operational amplifier OP4 and the first terminal of the thirty-fourth resistor R 34 ; the second terminal of the thirty-fourth resistor R 34 is connected to the output terminal of the fourth operational amplifier OP4; the second terminal of the thirty-third resistor R 33 is connected to the main power circuit.

[0063] The thirty-fifth resistor R 35 The first terminal of which is grounded; the thirty-fifth resistor R 35 The second terminal of which is respectively connected to the non-inverting input terminal of the fifth operational amplifier OP5 and the first terminal of the thirty-sixth resistor R 36 The thirty-sixth resistor R 36 The second terminal of which is connected to the main power circuit.

[0064] The thirty-seventh resistor R 37 The first terminal of which is respectively connected to the inverting input terminal of the fifth operational amplifier OP5 and the first terminal of the thirty-eighth resistor R 38 The thirty-eighth resistor R 38 The second terminal of which is connected to the output terminal of the fifth operational amplifier OP5; the second terminal of the thirty-seventh resistor R 37 The second terminal of which is grounded.

[0065] The current limiting state judging circuit is used to judge whether to enter or exit the current limiting state according to the information data and output a signal to the current closed-loop current limiting control circuit.

[0066] The current limiting state judging circuit includes: an inverse SR latch U1, an AND gate AND1, a first comparator AND1, a second comparator CMP2, a ninth triode T9, a nineteenth resistor R 19 a twentieth resistor R 20 a twenty-first resistor R 21 a twenty-second resistor R 22 a twenty-third resistor R 23 a twenty-fourth resistor R 24 a twenty-fifth resistor R 25 and a twenty-sixth resistor R 26 .

[0067] The inverting input terminal of the first comparator CMP1 is connected to one end of the twentieth resistor R 20 The other end of the twentieth resistor R 20 is connected to the feedback circuit; the non-inverting input terminal of the first comparator CMP1 is connected to the terminal Ref2 corresponding to the second reference voltage; the output terminal of the first comparator CMP1 is respectively connected to the first terminal of the nineteenth resistor R 19 and the set terminal of the inverse SR latch U1; the second terminal of the nineteenth resistor R 19 is connected to the DC voltage source; the emitter of the ninth triode T9 is grounded; the base of the ninth triode T9 is connected to the first terminal of the twenty-first resistor R 21 The collector of the ninth triode T9 is connected to the first terminal of the twenty-second resistor R 22 The twenty-first resistor R 21The second terminal of 22 is connected to the second terminal of the twenty-third resistor R 23 and the inverting input terminal of the second comparator CMP2; the second terminal of the twenty-third resistor R 23 is connected to the feedback circuit.

[0068] The first terminal of the twenty-fourth resistor R 24 is connected to the feedback circuit; the second terminal of the twenty-fourth resistor R 24 is respectively connected to the non-inverting input terminal of the second comparator CMP2 and the first terminal of the twenty-fifth resistor R 25 ; the second terminal of the twenty-fifth resistor R 25 is grounded.

[0069] The first input terminal of the AND gate AND1 is connected to the output terminal of the second comparator CMP2; the output terminal of the AND gate AND1 is connected to the reset terminal of the reverse SR latch U1; the first terminal of the twenty-sixth resistor R 26 is connected to the output terminal of the second comparator CMP2; the second terminal of the twenty-sixth resistor R 26 is connected to the DC voltage source VCC.

[0070] The non-inverting output terminal of the reverse SR latch U1 is connected to the current closed-loop current limiting control circuit.

[0071] The current closed-loop current limiting control circuit is used to receive the signal output by the current limiting state judgment circuit and adjust the control voltage corresponding to the main branch power transistor in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel.

[0072] The current closed-loop current limiting control circuit includes: the first operational amplifier OP1, the second operational amplifier OP2, the N-channel depletion-mode power transistor S1, the fifth diode D5, the third capacitor C3, the eleventh resistor R 11 , the twelfth resistor R 12 , the thirteenth resistor R 13 , the fourteenth resistor R 14 , the fifteenth resistor R 15 , the sixteenth resistor R 16 , the seventeenth resistor R 17 and the eighteenth resistor R 18 .

[0073] The anode of the fifth diode D5 is connected to the main branch drive power amplifier circuit; the cathode of the fifth diode D5 is connected to the drain D of the N-channel depletion-mode power transistor S1.

[0074] The first terminal of the eleventh resistor R 11The first terminal of is connected to the current-limiting state judgment circuit; the eleventh resistor R 11 The second terminal of is respectively connected to the gate G of the N-channel depletion-mode power transistor S1 and the twelfth resistor R 12 The first terminal of ; the source S of the N-channel depletion-mode power transistor S1 is respectively connected to the second terminal of the twelfth resistor R 12 And the first terminal of the thirteenth resistor R 13 Are connected.

[0075] The thirteenth resistor R 13 , the fourteenth resistor R 14 And the first operational amplifier OP1 form a voltage follower; among them, the second terminal of the thirteenth resistor R 13 Is connected to the output terminal of the first operational amplifier OP1; the first terminal of the fourteenth resistor R 14 Is connected to the output terminal of the first operational amplifier OP1; the second terminal of the fourteenth resistor R 14 Is connected to the inverting input terminal of the first operational amplifier OP1; the non-inverting input terminal of the first operational amplifier OP1 is connected to the first terminal of the fifteenth resistor R 15 .

[0076] The fifteenth resistor R 15 The second terminal of is respectively connected to the output terminal of the second operational amplifier OP2, the first terminal of the sixteenth resistor R 16 And the first terminal of the seventeenth resistor R 17 Are connected; the second terminal of the sixteenth resistor R 16 Is connected to the first terminal of the third capacitor C3; the second terminal of the third capacitor C3 is respectively connected to the second terminal of the seventeenth resistor R 17 , the first terminal of the eighteenth resistor R 18 And the inverting input terminal of the second operational amplifier OP2; the second terminal of the eighteenth resistor R 18 Is connected to the feedback circuit; the non-inverting input terminal of the second operational amplifier OP2 is connected to the terminal Ref1 corresponding to the first reference voltage.

[0077] This application aims to solve the problem that the impact current generated when the DC SSPC quickly connects a large capacitive load is likely to cause misprotection and thermal failure. The system adds a current-limiting branch to the main power branch, and combines an RC network and a current closed-loop current-limiting control circuit to control the working state of the MOSFET in stages, achieving effective suppression of the impact current. When it is detected that the impact current enters the current-limiting state, the main branch is turned off under the action of the current closed-loop current-limiting control circuit, while the current-limiting branch is turned on. The current-limiting branch quickly suppresses the impact current and pre-charges the load capacitor. As the impact current decreases, the main branch is gradually turned on, and the system charges the load capacitor with a constant current. Therefore, the SSPC current-limiting control time adapts to the load. During the current-limiting process, the main branch and the current-limiting branch of the system commutate naturally and the thermal stress of the power devices is reasonably distributed, improving the control stability and thermal reliability. In addition, when exiting the current-limiting state, the main branch is slowly turned on again under the control of the RC network, further suppressing the secondary impact current. This application can balance thermal reliability and rapidity, and has the advantages of strong load adaptability, simple control and strong practicability, and is applicable to fields such as aircraft, tanks, ships and civil power distribution networks.

[0078] This system adds a current-limiting branch to the main power circuit, and combines an RC network and a current closed-loop to form a DC SSPC current-limiting control system.

[0079] Figure 1 It is the system principle block diagram; including: main power circuit, main branch RC network, current-limiting branch RC network, main branch drive power amplifier circuit, current-limiting branch drive power amplifier circuit, current feedback circuit, load voltage feedback circuit, power supply voltage feedback circuit, current-limiting state judgment circuit and current closed-loop current-limiting control circuit.

[0080] Among them, in practical applications, the main power circuit is used to provide the current path of the power distribution channel. The main branch RC network is used to generate a control voltage to control the normal turn-on / turn-off of the main branch. The current-limiting branch RC network is used to generate a control voltage to control the normal turn-on / turn-off of the current-limiting branch. The main branch drive power amplifier circuit is used to amplify the power of the main branch control signal to drive the main branch power transistor. The current-limiting branch drive power amplifier circuit is used to amplify the power of the current-limiting branch control signal to drive the current-limiting branch power transistor. The current feedback circuit is used to detect the SSPC channel current in real time. The load voltage feedback circuit is used to detect the load voltage in real time. The power supply voltage feedback circuit is used to detect the input voltage of the SSPC in real time. The current-limiting state judgment circuit judges whether the SSPC enters / exits the current-limiting state according to the SSPC channel current, load voltage and input voltage. The current closed-loop current-limiting control circuit automatically adjusts the drive voltage of the main branch power transistor according to the SSPC channel current to achieve constant current control of the power distribution channel.

[0081] The main power circuit includes: main branch, current-limiting branch and detection resistor Rsense The main branch is composed of the first power transistor Q1, and the current-limiting branch is composed of the second power transistor Q2 and the current-limiting resistor R Limit connected in series. The drain D of the second power transistor Q2 is connected to the first terminal of the current-limiting resistor R Limit . The main branch is in parallel with the current-limiting branch. The source S of the first power transistor Q1 in the main branch and the source S of the second power transistor Q2 in the current-limiting branch are connected to the analog circuit ground Fgnd. The drain D of the first power transistor Q1 in the main branch is connected to the second terminal of the current-limiting resistor R Limit in the current-limiting branch. One end of this parallel structure is the power input terminal P in of the DC solid-state power controller, which is connected to the positive pole of the external DC power source; the other end is connected in series with the detection resistor R sense to serve as the power output terminal P out of the DC SSPC, which is connected to the load to the power ground (i.e., the grounding terminal).

[0082] When the DC SSPC receives the turn-on command, the driving voltage of the main branch, that is, the driving voltage U GS-main output by the driving power amplifier circuit of the main branch, rises exponentially with a time constant τ1 under the control of the main-branch RC network. At the same time, the driving voltage of the current-limiting branch, that is, the driving voltage U GS-Limit output by the driving power amplifier circuit of the current-limiting branch, rises exponentially with a time constant τ2 (τ2 < τ1) under the control of the current-limiting-branch RC network. Therefore, the rising speed of the driving voltage U GS-Limit of the current-limiting branch is faster than that of the driving voltage U GS-main of the main branch.

[0083] When the DC SSPC is connected to a large capacitive load, when the driving voltage U GS-Limit of the current-limiting branch rises to the turn-on voltage U GS-th-Limit of the second power transistor Q2, the current-limiting branch starts to conduct, and the SSPC current I SSPC rises rapidly. Due to the existence of the current-limiting resistor R Limit , the inrush current is effectively suppressed. When the SSPC current feedback value, that is, the SSPC channel current I FB is fed back to the corresponding voltage in the current-limiting state judgment circuit and rises to the second reference voltage, the current-limiting state judgment circuit outputs a high-level Limit signal. Under the action of the current closed-loop current-limiting control circuit, the main-branch driving control signal U gc-main is pulled low, and the first power transistor Q1 is in the off state. At this time, the load capacitor and the current-limiting resistor R Limit constitute a first-order RC circuit, and the SSPC current I SSPC exponentially decreases as the load capacitor is charged. When the difference between the SSPC current feedback value I FB and the first reference voltage decreases to a certain extent, the current closed-loop control circuit controls the driving voltage U GS-mainGradually rises. In this stage, the current-limiting resistor R Limit endures the main thermal stress.

[0084] When the driving voltage U of the main branch GS-main reaches the turn-on voltage U of the first power transistor Q1 GS-th-main , the main branch starts to conduct. Under the action of the current closed-loop current-limiting control circuit, the SSPC current I SSPC remains at a constant value, and the load voltage rises linearly. As the load voltage rises, the SSPC current I SSPC gradually commutates from the current-limiting branch to the main branch naturally. In this stage, the current-limiting resistor R Limit shares the thermal stress with the first power transistor Q1, and the duration of this stage decreases adaptively with the decrease of the load capacitance value.

[0085] When the feedback value U of the load voltage L_FB reaches the voltage threshold U th , the output Limit signal of the current-limiting state judgment circuit is reset to a low level, and the current-limiting control circuit is cut out of the control loop. At this time, the DC SSPC exits the current-limiting state. Subsequently, the driving voltage U of the main branch GS-Limit is controlled by the RC network of the main branch again and rises exponentially, realizing the secondary slow turn-on of the DC SSPC, thereby further suppressing the inrush current. Finally, the main branch is fully conducted and bypasses the current-limiting branch until the load capacitance is fully charged.

[0086] Figure 2 include the RC network of the main branch, the RC network of the current-limiting branch, the driving power amplifier circuit of the main branch, the driving power amplifier circuit of the current-limiting branch, and the current closed-loop current-limiting control circuit. The RC network of the main branch consists of two NPN-type triodes (the first triode T1 and the second triode T2), two diodes (the first diode D1 and the second diode D2), one capacitor (the first capacitor C1), and five resistors (the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the fifth resistor R5). One end of the first resistor R1 is connected to the switch control signal CMD, and the other end is connected to the base of the first triode T1. The collector of the first triode T1, the base of the second triode T2, and the first terminal of the second resistor R2 are jointly connected to node A. The second terminal of the second resistor R2 and the first terminal of the third resistor R3 are both connected to the positive pole of the DC voltage source VCC. The collector of the second triode T2, the second terminal of the third resistor R3, the anode of the first diode D1, and the cathode of the second diode D2 are jointly connected to node B. The cathode of the first diode D1 is connected to the first terminal of the fourth resistor R4; the anode of the second diode D2 is connected to the first terminal of the fifth resistor R5. The second terminal of the fourth resistor R4, the second terminal of the fifth resistor R5, and the first terminal of the first capacitor C1 are jointly connected to the driving control signal U of the main branch gc-mainThe emitter of the first triode T1, the emitter of the second triode T2, and the second terminal of the first capacitor C1 are all connected to the analog circuit ground Fgnd.

[0087] The current-limiting branch RC network consists of two NPN-type triodes (the third triode T3 and the fourth triode T4), two diodes (the third diode D3 and the fourth diode D4), one capacitor (the second capacitor C2), and five resistors (the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R 10 ). One end of the sixth resistor R6 is connected to the switch control signal CMD, and the other end is connected to the base of the third triode T3. The collector of the third triode T3, the base of the fourth triode T4, and the first terminal of the seventh resistor R7 are commonly connected to node C. The second terminal of the seventh resistor R7 and the first terminal of the eighth resistor R8 are both connected to the positive pole of the DC voltage source VCC. The collector of the fourth triode T4, the second terminal of the eighth resistor R8, the anode of the third diode D3, and the cathode of the fourth diode D4 are commonly connected to node E. The cathode of the third diode D3 is connected to the first terminal of the ninth resistor R9; the anode of the fourth diode D4 is connected to the first terminal of the tenth resistor R 10 . The second terminal of the ninth resistor R9, the second terminal of the tenth resistor R 10 , and the first terminal of the second capacitor C2 are commonly connected to the current-limiting branch drive control signal U gc-Limit . The emitter of the third triode T3, the emitter of the fourth triode T4, and the second terminal of the second capacitor C2 are all connected to the analog circuit ground Fgnd.

[0088] The main branch drive power amplifier circuit consists of an NPN triode (the fifth triode T5) and a PNP triode (the sixth triode T6). The collector of the fifth triode T5 is connected to the positive pole of the DC voltage source VCC. The base of the fifth triode T5 and the base of the sixth triode T6 are commonly connected to the above-mentioned main branch drive control signal U gc-main . The emitter of the fifth triode T5 and the emitter of the sixth triode T6 are commonly connected to the gate G of the first power transistor Q1. The collector of the sixth triode T6 is connected to the analog circuit ground Fgnd.

[0089] The current-limiting branch drive power amplifier circuit consists of an NPN triode (the seventh triode T7) and a PNP triode (the eighth triode T8). The collector of the seventh triode T7 is connected to the positive pole of the DC voltage source VCC. The base of the seventh triode T7 and the base of the eighth triode T8 are commonly connected to the above-mentioned current-limiting branch drive control signal U gc-Limit。The emitters of the seventh triode T7 and the eighth triode T8 are commonly connected to the gate G of the first power transistor Q2. The collector of the eighth triode T8 is connected to the analog circuit ground Fgnd.

[0090] The current closed-loop current-limiting control circuit consists of two operational amplifiers (the first operational amplifier OP1 and the second operational amplifier OP2), an N-channel depletion-mode power transistor S1, a diode (the fifth diode D5), a capacitor (the third capacitor C3), eight resistors (the eleventh resistor R 11 , the twelfth resistor R 12 , the thirteenth resistor R 13 , the fourteenth resistor R 14 , the fifteenth resistor R 15 , the sixteenth resistor R 16 , the seventeenth resistor R 17 , the eighteenth resistor R 18 ) and a terminal Ref1 corresponding to a first reference voltage. The anode of the fifth diode D5 is connected to the above-mentioned main branch drive control signal U gc-main , and the other end is connected to the drain D of the N-channel depletion-mode power transistor S1; the first terminal of the eleventh resistor R 11 is connected to the output terminal Limit of the current-limiting state judgment circuit; the gate G of the N-channel depletion-mode power transistor S1, the second terminal of the eleventh resistor R 11 , and the first terminal of the twelfth resistor R 12 are connected to the node F; the source S of the N-channel depletion-mode power transistor S1, the second terminal of the twelfth resistor R 12 , and the first terminal of the thirteenth resistor R 13 are connected to the node H; the thirteenth resistor R 13 , the fourteenth resistor R 14 , and the first operational amplifier OP1 form a voltage follower; the first terminal of the fifteenth resistor R 15 is connected to the non-inverting input terminal of the first operational amplifier OP1, and the other end is connected to the output terminal of the second operational amplifier OP2, the first terminal of the seventeenth resistor R 17 , and the second terminal of the sixteenth resistor R 16 are connected to the node I; the second terminal of the sixteenth resistor R 16 is connected to the first terminal of the third capacitor C3; the second terminal of the third capacitor C3, the second terminal of the seventeenth resistor R 17 , the first terminal of the eighteenth resistor R 18 , and the inverting input terminal of the second operational amplifier OP2 are connected to the node J; the non-inverting input terminal of the second operational amplifier OP2 is connected to the terminal Ref1 corresponding to the first reference voltage; the second terminal of the eighteenth resistor R 18 is connected to the output terminal of the current feedback circuit.

[0091] Figure 3 It includes a current feedback circuit, a load voltage feedback circuit, a power supply voltage feedback circuit, and a current limiting state judgment circuit. The current feedback circuit consists of the twenty-seventh resistor R 27 , the twenty-eighth resistor R 28 , the twenty-ninth resistor R 29 , the thirtieth resistor R 30 , and the third operational amplifier OP3 to form a differential amplifier circuit. The output terminal of this differential amplifier circuit is I FB . The positive differential input terminal is connected to the analog circuit ground Fgnd, and the negative differential input terminal is connected to the above-mentioned DC SSPC power output terminal P out . Among them, the resistance value of the twenty-seventh resistor R 27 is equal to the resistance value of the thirtieth resistor R 30 ; the resistance value of the twenty-eighth resistor R 28 is equal to the resistance value of the twenty-ninth resistor R 29 .

[0092] The load voltage feedback circuit consists of the thirty-first resistor R 31 , the thirty-second resistor R 32 , the thirty-third resistor R 33 , the thirty-fourth resistor R 34 , and the fourth operational amplifier OP4 to form a differential amplifier circuit. The output terminal of this differential amplifier circuit is U L_FB . The positive differential input terminal is connected to the above-mentioned DC SSPC power output terminal P out , and the negative differential input terminal is connected to the power ground. Among them, the resistance value of the thirty-first resistor R 31 is equal to the resistance value of the thirty-fourth resistor R 34 ; the resistance value of the thirty-second resistor R 32 is equal to the resistance value of the thirty-third resistor R 33 .

[0093] The power supply voltage feedback circuit consists of the thirty-fifth resistor R 35 , the thirty-sixth resistor R 36 , the thirty-seventh resistor R 37 , the thirty-eighth resistor R 38 , and the fifth operational amplifier OP5 to form a differential amplifier circuit. The output terminal of this differential amplifier circuit is U S_FB . The positive differential input terminal is connected to the above-mentioned DC SSPC power input terminal P in , and the negative differential input terminal is connected to the power ground. Among them, the resistance value of the thirty-fifth resistor R 35 is equal to the resistance value of the thirty-eighth resistor R 38 ; the resistance value of the thirty-sixth resistor R 36 is equal to the resistance value of the thirty-seventh resistor R 37 .

[0094] The current limiting state judgment circuit consists of an inverse SR latch U1, an AND gate AND1, two comparators (the first comparator CMP1 and the second comparator CMP2), an NPN transistor (the ninth transistor T9), eight resistors (the nineteenth resistor R 19 , the twentieth resistor R 20 , the twenty-first resistor R 21 , the twenty-second resistor R 22 , the twenty-third resistor R 23 , the twenty-fourth resistor R 24 , the twenty-fifth resistor R 25 , the twenty-sixth resistor R 26 ), and a terminal Ref2 corresponding to a second reference voltage. The inverting input terminal of the first comparator CMP1 is connected to the output terminal I of the above-mentioned current feedback circuit FB , and the non-inverting input terminal is connected to Ref2; the output terminal of the first comparator CMP1, the first terminal of the nineteenth resistor R 19 , and the set terminal of the inverse SR latch U1 are connected to the node K; the second terminal of the nineteenth resistor R 19 is connected to the positive pole of the DC voltage source VCC; the emitter of the ninth transistor T9 is connected to the analog circuit ground Fgnd, and the base is connected to the first terminal of the twenty-first resistor R 21 , and the collector of the ninth transistor T9 is connected to the first terminal of the twenty-second resistor R 22 ; the second terminal of the twenty-first resistor R 21 is connected to the inverse output terminal Limit' of the inverse SR latch U1; the second terminal of the twenty-second resistor R 22 , the first terminal of the twenty-third resistor R 23 , and the inverting input terminal of the second comparator CMP2 are connected to the node L; the second terminal of the twenty-third resistor R 23 is connected to the output terminal U of the above-mentioned load voltage feedback circuit L_FB ; the first terminal of the twenty-fourth resistor R 24 is connected to the output terminal U of the above-mentioned power supply voltage feedback circuit S_FB ; the twenty-fourth resistor R 24 and the twenty-fifth resistor R 25 divide the power supply voltage feedback value U S_FB to form a node voltage U th ; U th is connected to the non-inverting input terminal of the second comparator CMP2; the twenty-fifth resistor R 25The second terminal of is connected to the analog circuit ground Fgnd; the first input terminal of the AND gate AND1 is connected to the output terminal of the second comparator CMP2, the second input terminal of the AND gate AND1 is connected to the switch control signal CMD, and the output terminal of the AND gate AND1 is connected to the reset terminal of the reverse SR latch U1; the twenty-sixth resistor R 26 is the pull-up resistor of the second comparator CMP2. One end of the twenty-sixth resistor R 26 is connected to the output terminal of the second comparator CMP2, and the other end is connected to the positive pole of the DC voltage source VCC; the non-inverting output terminal Limit of the reverse SR latch U1 is connected to the current closed-loop current limiting control circuit.

[0095] The embodiment of the present application also provides a control method for a DC SSPC current limiting control system, and this method is implemented by using the DC SSPC current limiting control system; the method includes:

[0096] Obtain the switch control signal and generate a control voltage according to the switch control signal; perform power amplification processing on the control voltage to obtain the processed voltage; perform conduction or cutoff processing on the branch power distribution channel according to the processed voltage to provide a current path. Determine the corresponding information data based on the current path; the information data includes: SSPC channel current, load voltage, and SSPC input voltage; the SSPC channel current is the output current of the main power circuit; the SSPC input voltage is the input voltage of the main power circuit.

[0097] Judge whether to enter or exit the current limiting state according to the information data, and output a signal to the current closed-loop current limiting control circuit, and adjust the control voltage corresponding to the main branch power tube in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel.

[0098] As an optional implementation manner, performing conduction or cutoff processing on the branch power distribution channel according to the processed voltage to provide a current path specifically includes:

[0099] When the driving voltage output by the current limiting branch drive power amplification circuit rises to the turn-on voltage of the second power tube, the current limiting branch in the main power circuit conducts; when the driving voltage output by the main branch drive power amplification circuit reaches the turn-on voltage of the first power tube, the main branch in the main power circuit conducts.

[0100] In an embodiment, judging whether to enter or exit the current limiting state according to the information data, and outputting a signal to the current closed-loop current limiting control circuit, and adjusting the control voltage corresponding to the main branch power tube in the RC network according to the SSPC channel current to achieve constant current control of the power distribution channel specifically includes:

[0101] When the current of the SSPC channel is fed back to the corresponding voltage in the current limiting state judging circuit and rises to the second reference voltage, the signal output by the current limiting state judging circuit is at a high level. At this time, according to the SSPC channel current and the said signal, the current closed-loop current limiting control circuit pulls down the main branch drive control signal, and the first power tube is in the off state; the high level is a voltage value greater than the set voltage; the main branch drive control signal is the control voltage output by the main branch RC network.

[0102] When the difference between the current of the SSPC channel fed back to the corresponding voltage in the current closed-loop current limiting control circuit and the first reference voltage decreases to within the set threshold range, the current closed-loop current limiting control circuit controls the main branch drive control signal to rise.

[0103] When the load voltage reaches the voltage threshold, the signal output by the current limiting state judging circuit is reset to a low level, and the current closed-loop current limiting control circuit is cut out of the control loop. At this time, the current limiting state is exited; the main branch drive control signal rises exponentially under the control of the main branch RC network to suppress the inrush current. At this time, the main branch conducts and bypasses the current limiting branch; the low level is a voltage value less than the set voltage.

[0104] Figure 4 It is the working timing diagram of the embodiment of the present application when starting a large pure capacitive load.

[0105] At time t1, the switch control instruction CMD issues a high level, and the main branch drive voltage U GS-main rises exponentially with a time constant τ1 under the control of the main branch RC network. At the same time, the current limiting branch drive voltage U GS-Limit rises exponentially with a time constant τ2 under the control of the current limiting branch RC network, and τ 1> τ2, the rising speed of the current limiting branch drive voltage U GS-Limit is faster than that of the main branch drive voltage U GS-main .

[0106] t2 - t3: At time t2, the current limiting branch drive voltage U GS-Limit rises to the turn-on voltage U GS-th-Limit of the second power tube Q2, the current limiting branch starts to conduct, and the SSPC current I SSPC rises rapidly. Due to the existence of the current limiting resistor R Limit , the inrush current is suppressed. When the feedback value I FB of the SSPC current rises to the second voltage reference Ref2, the current limiting state judging circuit outputs Limit as a high level. Under the action of the current closed-loop current limiting control circuit, the main branch drive control signal U gc-main is pulled down, and the first power tube Q1 is in the off state. The load capacitor and the current limiting resistor R Limit form a first-order RC circuit. As the load capacitor is charged, the SSPC current ISSPC The exponential decreases, and the difference between the SSPC current feedback value I FB and the first voltage reference Ref1 decreases. After a certain time, the current closed-loop control circuit controls the main branch drive voltage U GS-main to gradually rise. During this stage, the current-limiting resistor R Limit endures the main thermal stress.

[0107] t3 - t4: At time t3, the main branch drive voltage U GS-main reaches the turn-on voltage U GS-th-main of the first power transistor Q1, and the main branch starts to conduct. Under the action of the current closed-loop current-limiting control circuit, the SSPC current I SSPC remains at a constant value, the load voltage rises linearly, and the SSPC current I SSPC gradually commutates from the current-limiting branch to the main branch naturally. During this stage, the current-limiting resistor R Limit and the first power transistor Q1 share the thermal stress together, and the duration of this stage decreases adaptively with the decrease of the load capacitance value.

[0108] t4 - t5: At time t4, the load voltage line feedback value U L_FB reaches the voltage threshold U th , the current-limiting state judgment circuit outputs a current-limiting signal Limit to be reset to a low level, the current-limiting control circuit is cut out of the control loop, and at this time the DC SSPC exits the current-limiting state. Subsequently, the main branch drive voltage U GS-Limit is exponentially increased again under the control of the main branch RC network, the DC SSPC is slowly turned on for the second time, and the inrush current is suppressed for the second time.

[0109] At time t5, the load capacitor is fully charged, and the SSPC current I SSPC drops to 0.

[0110] The beneficial effects of this application are as follows:

[0111] 1) When the DC SSPC is connected to a large capacitive load, it can quickly suppress the inrush current, avoid misjudging as a short-circuit fault and tripping, and improve the load compatibility.

[0112] 2) Utilizing the principle of current closed-loop control, the SSPC has the characteristic that the current-limiting control time changes adaptively with the load, thus achieving the goal of quickly connecting the DC SSPC to a large capacitive load and improving the rapidity of the system.

[0113] 3) Making full use of the thermal capacity of the power devices in the DC SSPC, improving the thermal reliability of the system, and reducing the volume, weight and cost of the DC SSPC.

[0114] 4) During the current-limiting control process, the SSPC current can commutate from the current-limiting branch to the main branch naturally, with simple control, good stability, strong practicability and high reliability.

[0115] 5) During the process of the DC SSPC starting a capacitive load, when exiting the current limiting state, the main branch is controlled by the main branch RC network again and slowly turns on, effectively suppressing the generation of the secondary inrush current.

[0116] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0117] Specific examples are used in this article to elaborate on the principle and implementation manner of this application. The description of the above embodiments is only used to help understand the system of this application and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of this application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to this application.

Claims

1. A DC SSPC current limiting control system, characterized in that: include: Main power circuit, RC network, driving power amplifier circuit, feedback circuit, current limiting state judgment circuit and current closed-loop current limiting control circuit; The main power circuit is connected to the driving power amplifier circuit and the feedback circuit respectively; the RC network is connected to the driving power amplifier circuit; the current limiting state judgment circuit is connected to the feedback circuit; the current closed-loop current limiting control circuit is connected to the current limiting state judgment circuit, the feedback circuit and the RC network respectively; The RC network is used to generate a control voltage according to the switch control signal; The driving power amplifier circuit is used to perform power amplification processing on the control voltage to obtain a processed voltage; The main power circuit is used to turn on or off the branch power distribution channel according to the processed voltage to provide a current path; The feedback circuit is used to obtain information data and feed it back to the current limiting state judgment circuit and the current closed-loop current limiting control circuit; the information data includes: SSPC channel current, load voltage and SSPC input voltage; SSPC channel current is the output current of the main power circuit; SSPC input voltage is the input voltage of the main power circuit; The current limiting state judgment circuit is used to judge whether to enter or exit the current limiting state according to the information data, and output a signal to the current closed-loop current limiting control circuit; The current closed-loop current limiting control circuit is used to receive the signal output by the current limiting state judgment circuit, and adjust the control voltage corresponding to the main branch power tube in the RC network according to the SSPC channel current to achieve constant current control of the distribution channel.

2. The DC SSPC current limiting control system according to claim 1 is characterized in that: The main power circuit comprises: a main branch, a current limiting branch and a detection resistor; The main branch is connected in parallel with the current limiting branch, and after being connected in parallel, they are connected in series with the detection resistor; Wherein, the main branch includes: a first power tube; the current limiting branch includes: a second power tube and a current limiting resistor; The source of the first power tube is connected to the source of the second power tube; the drain of the second power tube is connected to the first terminal of the current limiting resistor; and the drain of the first power tube is connected to the second terminal of the current limiting resistor.

3. The DC SSPC current limiting control system according to claim 2 is characterized in that: The RC network includes: a main branch RC network and a current limiting branch RC network; The main branch RC network and the current limiting branch RC network are connected in parallel and are both connected to the driving power amplifier circuit; Wherein, the main branch RC network includes a first triode, a second triode, a first diode, a second diode, a first capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor and a fifth resistor; The current limiting branch RC network includes a third triode, a fourth triode, a third diode, a fourth diode, a second capacitor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor; One end of the first resistor is connected to the base of the first triode; the emitter of the first triode is grounded; the collector of the first triode is respectively connected to the base of the second triode and the first terminal of the second resistor; the second terminal of the second resistor and the first terminal of the third resistor are both connected to a DC voltage source; the collector of the second triode is respectively connected to the second terminal of the third resistor, the anode of the first diode and the cathode of the second diode; the cathode of the first diode is connected to the first terminal of the fourth resistor; the anode of the second diode is connected to the first terminal of the fifth resistor; the second terminal of the fourth resistor is connected to the second terminal of the fifth resistor, and the second terminal of the fifth resistor is connected to the first terminal of the first capacitor; the second terminal of the fourth resistor, the second terminal of the fifth resistor and the first terminal of the first capacitor are also connected to the driving power amplifier circuit; the emitter of the second triode is grounded; the second terminal of the first capacitor is grounded; One end of the sixth resistor is connected to the other end of the first resistor; the other end of the sixth resistor is connected to the base of the third triode; the emitter of the third triode is grounded; the collector of the third triode is respectively connected to the base of the fourth triode and the first terminal of the seventh resistor; the emitter of the fourth triode is grounded; the collector of the fourth triode is respectively connected to the second terminal of the eighth resistor, the anode of the third diode and the cathode of the fourth diode; the second terminal of the seventh resistor and the first terminal of the eighth resistor are both connected to a DC voltage source; The cathode of the third diode is connected to the first terminal of the ninth resistor; the anode of the fourth diode is connected to the first terminal of the tenth resistor; the second terminal of the ninth resistor is connected to the second terminal of the tenth resistor, and the second terminal of the tenth resistor is connected to the first terminal of the second capacitor; the second terminal of the ninth resistor, the second terminal of the tenth resistor and the first terminal of the second capacitor are also connected to the driving power amplifier circuit; the second terminal of the second capacitor is grounded.

4. The DC SSPC current limiting control system according to claim 3 is characterized in that: The driving power amplifier circuit includes: a main branch driving power amplifier circuit and a current limiting branch driving power amplifier circuit; The main branch driving power amplifier circuit includes a fifth transistor and a sixth transistor; the current limiting branch driving power amplifier circuit includes a seventh transistor and an eighth transistor; The collector of the fifth transistor is connected to the DC voltage source; the base of the fifth transistor is connected to the base of the sixth transistor, and both are connected to the main branch RC network; The emitter of the fifth triode is connected to the emitter of the sixth triode, and both are connected to the gate of the first power tube; the collector of the sixth triode is grounded; The collector of the seventh transistor is connected to the DC voltage source; the base of the seventh transistor is connected to the base of the eighth transistor, and both are connected to the current limiting branch RC network; The emitter of the seventh triode is connected to the emitter of the eighth triode, and both are connected to the grid of the second power tube; the collector of the eighth triode is grounded.

5. The DC SSPC current limiting control system according to claim 4, characterized in that: The current closed-loop current limiting control circuit comprises: a first operational amplifier, a second operational amplifier, an N-channel depletion-type power tube, a fifth diode, a third capacitor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor and an eighteenth resistor; The anode of the fifth diode is connected to the main branch driving power amplifier circuit; the cathode of the fifth diode is connected to the drain of the N-channel depletion-type power tube; The first terminal of the eleventh resistor is connected to the current limiting state judgment circuit; the second terminal of the eleventh resistor is respectively connected to the gate of the N-channel depletion-type power tube and the first terminal of the twelfth resistor; the source of the N-channel depletion-type power tube is respectively connected to the second terminal of the twelfth resistor and the first terminal of the thirteenth resistor; The thirteenth resistor, the fourteenth resistor and the first operational amplifier form a voltage follower; wherein the second terminal of the thirteenth resistor is connected to the output end of the first operational amplifier; the first terminal of the fourteenth resistor is connected to the output end of the first operational amplifier; the second terminal of the fourteenth resistor is connected to the reverse input end of the first operational amplifier; the non-inverting input end of the first operational amplifier is connected to the first terminal of the fifteenth resistor; The second terminal of the fifteenth resistor is respectively connected to the output end of the second operational amplifier, the first terminal of the sixteenth resistor and the first terminal of the seventeenth resistor; the second terminal of the sixteenth resistor is connected to the first terminal of the third capacitor; the second terminal of the third capacitor is respectively connected to the second terminal of the seventeenth resistor, the first terminal of the eighteenth resistor and the inverting input end of the second operational amplifier; the second terminal of the eighteenth resistor is connected to the feedback circuit; the non-inverting input end of the second operational amplifier is connected to the terminal corresponding to the first reference voltage.

6. The DC SSPC current limiting control system according to claim 1, characterized in that: The current limiting state judgment circuit includes: an inverted SR latch, an AND gate, a first comparator, a second comparator, a ninth transistor, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, a twenty-fifth resistor and a twenty-sixth resistor; The inverting input terminal of the first comparator is connected to one end of the twentieth resistor; the other end of the twentieth resistor is connected to the feedback circuit; the non-inverting input terminal of the first comparator is connected to the terminal corresponding to the second reference voltage; the output terminal of the first comparator is respectively connected to the first terminal of the nineteenth resistor and the set terminal of the reverse SR latch; the second terminal of the nineteenth resistor is connected to the DC voltage source; the emitter of the ninth transistor is grounded; the base of the ninth transistor is connected to the first terminal of the twenty-first resistor; the collector of the ninth transistor is connected to the first terminal of the twenty-second resistor; the second terminal of the twenty-first resistor is connected to the inverting output terminal of the reverse SR latch; the second terminal of the twenty-second resistor is respectively connected to the first terminal of the twenty-third resistor and the inverting input terminal of the second comparator; the second terminal of the twenty-third resistor is connected to the feedback circuit; The first terminal of the twenty-fourth resistor is connected to the feedback circuit; the second terminal of the twenty-fourth resistor is respectively connected to the non-inverting input terminal of the second comparator and the first terminal of the twenty-fifth resistor; the second terminal of the twenty-fifth resistor is grounded; The first input terminal of the AND gate is connected to the output terminal of the second comparator; the output terminal of the AND gate is connected to the reset terminal of the inverted SR latch; the first terminal of the twenty-sixth resistor is connected to the output terminal of the second comparator; the second terminal of the twenty-sixth resistor is connected to the DC voltage source; The non-inverting output terminal of the inverting SR latch is connected to the current closed-loop current limiting control circuit.

7. The DC SSPC current limiting control system according to claim 1, characterized in that: The feedback circuit includes: a current feedback circuit, a load voltage feedback circuit and a power supply voltage feedback circuit; The current feedback circuit includes: a twenty-seventh resistor, a twenty-eighth resistor, a twenty-ninth resistor, a thirtieth resistor and a third operational amplifier; The load voltage feedback circuit comprises: a thirty-first resistor, a thirty-second resistor, a thirty-third resistor, a thirty-fourth resistor and a fourth operational amplifier; The power supply voltage feedback circuit includes: a thirty-fifth resistor, a thirty-sixth resistor, a thirty-seventh resistor, a thirty-eighth resistor and a fifth operational amplifier; The first terminal of the twenty-seventh resistor is grounded; the second terminal of the twenty-seventh resistor is respectively connected to the non-inverting input terminal of the third operational amplifier and the first terminal of the twenty-eighth resistor; the second terminal of the twenty-eighth resistor is connected to the main power circuit; The first terminal of the twenty-ninth resistor is respectively connected to the inverting input terminal of the third operational amplifier and the first terminal of the thirtieth resistor; the second terminal of the thirtieth resistor is connected to the output terminal of the third operational amplifier; the second terminal of the twenty-ninth resistor is connected to the main power circuit; A first terminal of the thirty-first resistor is grounded; a second terminal of the thirty-first resistor is respectively connected to the non-inverting input terminal of the fourth operational amplifier and the first terminal of the thirty-second resistor; and a second terminal of the thirty-second resistor is connected to the main power circuit; The first terminal of the thirty-third resistor is respectively connected to the inverting input terminal of the fourth operational amplifier and the first terminal of the thirty-fourth resistor; the second terminal of the thirty-fourth resistor is connected to the output terminal of the fourth operational amplifier; and the second terminal of the thirty-third resistor is connected to the main power circuit; A first terminal of the thirty-fifth resistor is grounded; a second terminal of the thirty-fifth resistor is respectively connected to the non-inverting input terminal of the fifth operational amplifier and the first terminal of the thirty-sixth resistor; and a second terminal of the thirty-sixth resistor is connected to the main power circuit; The first terminal of the thirty-seventh resistor is respectively connected to the inverting input terminal of the fifth operational amplifier and the first terminal of the thirty-eighth resistor; the second terminal of the thirty-eighth resistor is connected to the output terminal of the fifth operational amplifier; and the second terminal of the thirty-seventh resistor is grounded.

8. A control method for a DC SSPC current limiting control system, characterized in that: The method is implemented by using the DC SSPC current limiting control system described in any one of claims 1 to 7; the control method of the DC SSPC current limiting control system includes: Acquire a switch control signal and generate a control voltage according to the switch control signal; Performing power amplification processing on the control voltage to obtain a processed voltage; Conducting or shutting down the branch power distribution channel according to the processed voltage to provide a current path; Determine corresponding information data based on the current path; the information data includes: SSPC channel current, load voltage and SSPC input voltage; SSPC channel current is the output current of the main power circuit; SSPC input voltage is the input voltage of the main power circuit; According to the information data, it is determined whether to enter or exit the current limiting state, and a signal is output to the current closed-loop current limiting control circuit. According to the SSPC channel current, the control voltage corresponding to the main branch power tube in the RC network is adjusted to achieve constant current control of the distribution channel.

9. The control method of the DC SSPC current limiting control system according to claim 8, characterized in that: The branch power distribution channel is turned on or off according to the processed voltage to provide a current path, specifically including: When the driving voltage output by the current limiting branch driving the power amplifier circuit rises to the turn-on voltage of the second power tube, the current limiting branch in the main power circuit is turned on; When the driving voltage output by the main branch driving power amplifier circuit reaches the turn-on voltage of the first power tube, the main branch in the main power circuit is turned on.

10. The control method of the DC SSPC current limiting control system according to claim 8, characterized in that: According to the information data, it is determined whether to enter or exit the current limiting state, and a signal is output to the current closed-loop current limiting control circuit. According to the SSPC channel current, the control voltage corresponding to the main branch power tube in the RC network is adjusted to achieve constant current control of the distribution channel, specifically including: When the SSPC channel current is fed back to the corresponding voltage in the current limiting state judgment circuit and rises to the second reference voltage, the signal output by the current limiting state judgment circuit is a high level. At this time, the current closed-loop current limiting control circuit pulls down the main branch drive control signal according to the SSPC channel current and the signal, and the first power tube is in the off state; the high level is a voltage value greater than the set voltage; the main branch drive control signal is the control voltage output by the main branch RC network; When the SSPC channel current is fed back to the corresponding voltage in the current closed-loop current limiting control circuit, and the difference between the current and the first reference voltage is reduced to within the set threshold range, the current closed-loop current limiting control circuit controls the main branch drive control signal to rise; When the load voltage reaches the voltage threshold, the signal output by the current limiting state judgment circuit is reset to a low level, and the current closed-loop current limiting control circuit is cut out of the control loop. At this time, the current limiting state is exited; the main branch drive control signal is controlled by the main branch RC network and the index rises to suppress the impact current. At this time, the main branch is turned on and the current limiting branch is bypassed; the low level is a voltage value less than the set voltage.

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