CN116865738B - DC solid-state circuit breaker circuit topology and control method based on semi-controlled devices - Google Patents

Abstract

The application belongs to the field of electronic circuits, in particular relates to a direct-current solid-state circuit breaker circuit topology based on a semi-controlled device and a control method, and aims to solve the problem that the direct-current solid-state circuit breaker based on a thyristor is high in cost and volume when bidirectional turn-off and multiport are realized. The application comprises the following steps: the first end of the direct current system, the second end of the lightning arrester, the second end of the first auxiliary switch and the second end of the second auxiliary switch are connected to the first node G1; the first end of the second auxiliary switch, the first end of the lightning arrester and the second end of the capacitor C1 are connected to a second node G2; the first end of the capacitor C1, the first end of the first auxiliary switch and the second end of the auxiliary branch are connected to the third node G3; the first end of the auxiliary branch is grounded through a fourth node G4; the application solves the problems of bidirectional turn-off and multi-port application of the direct current solid-state circuit breaker based on the thyristor, reduces the cost and the volume, and realizes the function of soft reclosing.

Description

DC solid-state circuit breaker circuit topology and control method based on semi-controlled devices

Technical field

The invention belongs to the field of electronic circuits, and specifically relates to a DC solid-state circuit breaker circuit topology and control method based on a semi-controlled device.

Background technique

In recent years, with the continuous development of power technology, connecting large-scale distributed power sources to the power grid has become a major trend in the future development of power grids. DC microgrids and DC distribution systems have become a research hotspot among domestic and foreign scholars due to their power supply flexibility and are suitable for large-scale distributed power grid connection scenarios. In DC systems, DC circuit breakers have been widely used in various DC system projects due to their fast response speed and good fault isolation selectivity. DC microgrids and power distribution systems with lower rated voltages have higher requirements for the response speed, intelligence, and integration of DC circuit breakers. Therefore, DC solid-state circuit breakers based on modern high-power power electronic devices are ideal for protecting DC microgrids and The optimal choice for power distribution systems, the extremely short breaking time and ultra-high switching frequency of power electronic devices create conditions for the integration of various functions of DC circuit breakers.

The power electronic devices currently used in DC solid-state circuit breakers can be divided into two types: fully controlled type and semi-controlled type. The fully controlled type device has a fast turn-off speed, but is expensive and has large conduction loss, so the semi-controlled type is used. The realization of DC solid-state circuit breakers by power electronic devices is a current research hotspot. Thyristors are typical semi-controlled power electronic devices. Semi-controlled power electronic devices using thyristors to realize DC solid-state circuit breakers can control conduction, but cannot control shutdown. ;

Developing a semi-controlled power electronic device to implement a DC solid-state circuit breaker is of great significance to DC microgrids and power distribution systems. Recently, some researchers have proposed DC solid-state circuit breaker solutions using thyristors, but these solutions require external When a circuit failure occurs, it is difficult to turn off the circuit, the speed and reliability are not high, and the cost and volume are relatively high when implementing bidirectional turn-off and multi-port.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, that is, the cost and volume of a thyristor-based DC solid-state circuit breaker are relatively high when realizing bidirectional turn-off and multi-port, the present invention provides a DC solid-state circuit breaker based on a semi-controlled device Circuit topology, the DC solid-state circuit breaker circuit topology based on semi-controlled devices includes: DC system, first auxiliary switch, second auxiliary switch, arrester MOV, capacitor C1 and auxiliary branch;

The first end of the DC system, the second end of the arrester, the second end of the first auxiliary switch and the second end of the second auxiliary switch are connected to the first node G1; the first end of the second auxiliary switch, the first end of the arrester terminal and the second terminal of the capacitor C1 are connected to the second node G2; the first terminal of the capacitor C1, the first terminal of the first auxiliary switch and the second terminal of the auxiliary branch are connected to the third node G3; the first terminal of the auxiliary branch One end is grounded through the fourth node G4;

The DC system includes n selection switches and n main flow branches;

The auxiliary branch includes: a first resistor R1, a second resistor R2 and a diode D1;

The second end of the auxiliary branch, the diode D1 and the first resistor R1 are connected through the third node G3; the diode D1 and the second resistor R2 are connected in series, and the end close to the second resistor R2 is the anode of the diode; the first end of the auxiliary branch , the first resistor R1 and the second resistor R2 are connected through the fourth node G4.

In a preferred embodiment, the DC system in the above-mentioned DC solid-state circuit breaker topology includes n parallel DC subsystems, n is a positive integer;

The first end of each DC subsystem is connected to the first end of the DC system, and the second end of each DC subsystem is connected to the second end of the DC system; each DC subsystem includes a main current branch and a selection switch. and a port;

The first end of the i-th DC subsystem is connected to the first end of the i-th main flow branch, the second end of the i-th DC subsystem is connected to the second end of the i-th selector switch, and the i-th main flow branch is connected to the second end of the i-th main flow branch. The two ends are connected to the i-th port, i is the serial number corresponding to any DC subsystem, and i is any integer from 1 to n.

In a preferred embodiment, the first auxiliary switch is composed of a one-way semi-controlled power electronic device or a one-way fully controlled power electronic device, and the second auxiliary switch is composed of a one-way semi-controlled power electronic device.

In a preferred embodiment, all selection switches are composed of unidirectional semi-controlled power electronic devices; all main flow branches are composed of low-loss semi-controlled power electronic devices connected in anti-parallel.

In another aspect of the present invention, a method for controlling the circuit topology of a DC solid-state circuit breaker based on a semi-controlled device is proposed, and the circuit topology of the DC solid-state circuit breaker based on the semi-controlled device operates;

When the external DC circuit connected by the DC solid-state circuit breaker circuit topology based on the semi-controlled device operates normally, the selector switches 1 to n are in the off state, the first auxiliary switch is in the off state, the second auxiliary switch is continuously on, and the capacitor C1 is charged to the DC bus voltage. When the voltage of capacitor C1 is charged to the DC system voltage, the second auxiliary switch is turned off;

When a short-circuit fault occurs in an external DC circuit connected to the DC solid-state circuit breaker circuit topology based on semi-controlled devices, the detection device detects an abnormal increase in current at the j-th port of the faulty DC circuit, and provides the j-th selector switch and the first auxiliary switch. When the signal is turned on, the fault current reversely charges the capacitor C1 until it reaches the clamping voltage of the arrester MOV. The arrester is triggered. The triggered arrester MOV consumes the voltage and current in the system, so that the current of the external circuit connected to the jth port is always safe. Under the threshold; j is the serial number of the DC subsystem corresponding to the external DC circuit where the short-circuit fault occurs.

After the fault is dealt with, turn off the first auxiliary switch. The current flowing through the jth selection switch is less than its maintaining current and then naturally turns off. Close the second auxiliary switch so that the second auxiliary switch is continuously turned on and the capacitor C1 is charged to DC. Bus voltage, when the voltage of capacitor C1 is charged to the DC bus voltage, turn off the second auxiliary switch, and then give the i-th selection switch conduction signal, capacitor C1 discharges to the j-th port where the faulty DC circuit is detected, and determines port i Whether the current peak value and voltage peak value reach the threshold value, if the current peak value reaches the first threshold value and the voltage peak value reaches the second threshold value, it means that the faulty port returns to normal.

Beneficial effects of the present invention:

(1) The present invention solves the problem that the cost and volume of a thyristor-based DC solid-state circuit breaker to achieve bidirectional turn-off or multi-port are too high.

(2) The present invention reduces the number of semi-controlled power electronic devices and lightning arresters when the DC solid-state circuit breaker circuit topology is configured in a multi-port configuration, and reduces the cost and volume of the multi-port DC solid-state circuit breaker.

(3) When the multi-port DC solid-state circuit breaker of the present invention is topologically disconnected, the influence of leakage current on the arrester is completely eliminated, thus solving the safety problem of the arrester.

(4) The present invention solves the existing unreliable reclosing problem of active back-pressure shutdown topology for semi-controlled power electronic devices, and can charge the capacitor when the main current branch of the fault port is not conductive. And it has the function of soft reclosing.

Description of the drawings

Other features, objects and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

Figure 1 is a specific structure of the circuit topology of a DC solid-state circuit breaker based on a semi-controlled device in an embodiment of the present invention;

Figure 2 is a schematic diagram of the external circuit topologically connected to the DC solid-state circuit breaker based on the semi-controlled device in the embodiment of the present invention when it is working normally;

Figure 3 is a schematic diagram of the DC solid-state circuit breaker circuit topological connection based on the semi-controlled device in the present invention when the external circuit fails;

Figure 4 is a schematic diagram of the DC solid-state circuit breaker circuit topology based on semi-controlled devices in the present invention when handling faults;

Figure 5 is a schematic diagram of the soft reclosing principle of the circuit topology of the DC solid-state circuit breaker based on the semi-controlled device in the present invention;

Figure 6 is another specific structure of the DC solid-state circuit breaker circuit topology based on the semi-controlled device proposed for the present invention.

Detailed ways

The present application will be further described in detail below in conjunction with the accompanying drawings and examples. It can be understood that the specific embodiments described here are only used to explain the relevant invention, but not to limit the invention. It should also be noted that, for convenience of description, only the parts related to the invention are shown in the drawings.

It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

In order to more clearly explain the circuit topology of the DC solid-state circuit breaker based on the semi-controlled device of the present invention, the following first embodiment will describe in detail each structure in the embodiment of the present invention with reference to FIG. 1 .

As shown in Figure 1, the present invention proposes a DC solid-state circuit breaker circuit topology based on semi-controlled devices. The DC solid-state circuit breaker topology includes: DC system, first auxiliary switch, second auxiliary switch, arrester MOV, capacitor C1 and auxiliary branch road;

Specifically, the first end of the DC system, the second end of the arrester, the second end of the first auxiliary switch and the second end of the second auxiliary switch are connected to the first node G1; the first end of the second auxiliary switch, the arrester The first end of the capacitor C1 and the second end of the capacitor C1 are connected to the second node G2; the first end of the capacitor C1, the first end of the first auxiliary switch and the second end of the auxiliary branch are connected to the third node G3; the auxiliary branch The first end of the road is grounded through the fourth node G4;

Specifically, the auxiliary branch includes: a first resistor R1, a second resistor R2 and a diode D1; wherein, the second end of the auxiliary branch, the diode D1 and the first resistor R1 are connected through the third node G3; the diode D1 and the second The resistor R2 is connected in series, and the end close to the second resistor R2 is the anode of the diode; the first end of the auxiliary branch, the first resistor R1 and the second resistor R2 are connected through the fourth node G4.

Specifically, the DC system includes n parallel DC subsystems, where n is a positive integer;

The first end of each DC subsystem is connected to the first end of the DC system, and the second end of each DC subsystem is connected to the second end of the DC system; each DC subsystem includes a main current branch and a selection switch. and a port;

The first end of the i-th DC subsystem is connected to the first end of the i-th main flow branch, the second end of the i-th DC subsystem is connected to the second end of the i-th selector switch, and the i-th main flow branch is connected to the second end of the i-th main flow branch. The two ends are connected to the i-th port, i is the serial number corresponding to any DC subsystem, and i is any integer from 1 to n.

Specifically, all selection switches are composed of one-way semi-controlled power electronic devices; all main flow branches are composed of low-loss semi-controlled power electronic devices in anti-parallel connection. The first auxiliary switch is composed of a one-way semi-controlled power electronic device or a one-way fully controlled power electronic device, and the second auxiliary switch is composed of a one-way semi-controlled power electronic device.

When the external DC circuit connected to the DC solid-state circuit breaker circuit topology is operating normally, the selector switches 1 to n are in the off state, the first auxiliary switch is in the off state, the second auxiliary switch is continuously on, and the capacitor C ₁ is charged to the DC bus voltage.

The invention solves the problem that the cost and volume of a thyristor-based DC solid-state circuit breaker that realizes bidirectional turn-off or multi-port are too high. The invention reduces the number of semi-controlled power electronic devices and lightning arresters when the DC solid-state circuit breaker circuit topology is configured with multiple ports, and reduces the cost and volume of the multi-port DC solid-state circuit breaker.

The second embodiment of the present invention proposes a control method for the circuit topology of a DC solid-state circuit breaker based on a semi-controlled device, which operates based on the circuit topology of the DC solid-state circuit breaker;

When the external DC circuit connected to the DC solid-state circuit breaker circuit topology is operating normally, the selector switches 1 to n are in the off state, the first auxiliary switch is in the off state, the second auxiliary switch is continuously on, and the capacitor C1 is charged to the DC bus voltage, when the voltage of capacitor C1 is charged to the DC system voltage, turn off the second auxiliary switch;

When a short-circuit fault occurs in the external DC circuit connected topologically to the DC solid-state circuit breaker circuit, the detection device detects an abnormal increase in the current of the j-th port of the faulty DC circuit, and gives the j-th selection switch and the first auxiliary switch a conduction signal, and the fault current Reverse charge the capacitor C1 until it reaches the clamping voltage of the arrester MOV, the arrester is triggered, and the triggered arrester MOV consumes the voltage and current in the system, so that the current of the external circuit connected to the j-th port is always under the safety threshold; j is The serial number of the DC subsystem corresponding to the external DC circuit where the short-circuit fault occurred.

After the fault is dealt with, turn off the first auxiliary switch. The current flowing through the jth selection switch is less than its maintaining current and then naturally turns off. Close the second auxiliary switch so that the second auxiliary switch is continuously turned on and the capacitor C1 is charged to DC. Bus voltage, when the voltage of capacitor C1 is charged to the DC bus voltage, turn off the second auxiliary switch, and then give the i-th selection switch conduction signal, capacitor C1 discharges to the j-th port where the faulty DC circuit is detected, and determines port i Whether the current peak value and voltage peak value reach the threshold value, if the current peak value reaches the first threshold value and the voltage peak value reaches the second threshold value, it means that the faulty port returns to normal.

The control method of the semi-controlled DC solid-state circuit breaker circuit topology of the present invention solves the problem of the high cost and volume of the thyristor-based DC solid-state circuit breaker to achieve bidirectional turn-off or multi-port, and reduces the problem of the DC solid-state circuit breaker circuit topology. The number of semi-controlled power electronic devices and lightning arresters in multi-port configuration reduces the cost and volume of the multi-port DC solid-state circuit breaker. When the DC solid-state circuit breaker circuit topology based on the semi-controlled type is disconnected, the influence of the leakage current on the arrester is completely eliminated, thus solving the safety problem of the arrester.

The working state of the semi-controlled DC solid-state circuit breaker circuit topology of the present invention will be described in detail with reference to FIG. 2 . Specifically, the load current flows through the first main current branch to the third main current branch when the DC system is operating normally. The main current branch is composed of semi-controlled power electronic devices connected in anti-parallel. The semi-controlled The anti-parallel configuration of the power electronics ensures that load current can be diverted at any time. When the external DC circuit is working normally, the second auxiliary switch is given a continuous conduction signal so that its working state is similar to that of a diode. The duration of the conduction signal depends on the size of the capacitor C1 and the first current-limiting resistor R1. When the capacitor After the voltage of C1 is charged to the DC system voltage, the conduction signal of the second auxiliary switch is turned off, and then the second auxiliary switch is turned off.

When a short-circuit fault occurs in the external DC circuit connected topologically to the DC solid-state circuit breaker circuit, the detection device detects an abnormal increase in the current of the j-th port of the faulty DC circuit, and gives the j-th selection switch and the first auxiliary switch a conduction signal, and the fault current The capacitor C1 is reversely charged until it reaches the clamping voltage of the arrester MOV, and the arrester is triggered. The triggered arrester MOV consumes the voltage and current in the system, so that the current of the external circuit connected to the j-th port is always under the safety threshold.

j is the serial number of the port and selection switch corresponding to the external DC circuit where the short-circuit fault occurs.

The abnormal rise here can be understood as if the current at the j-th port of the faulty DC circuit is greater than a threshold, it is considered abnormal, and the threshold can be set artificially;

After the fault is dealt with, turn off the first auxiliary switch. The current flowing through the jth selection switch is less than its maintaining current and then naturally turns off. Close the second auxiliary switch so that the second auxiliary switch is continuously turned on and the capacitor C1 is charged to DC. bus voltage, when the voltage of capacitor C1 is charged to the DC bus voltage, turn off the second auxiliary switch, and then give the jth selection switch conduction signal, capacitor C1 discharges to the jth port where the faulty DC circuit is detected, and the jth Whether the current peak value and voltage peak value of the port reach the threshold value. If the current peak value reaches the first threshold value and the voltage peak value reaches the second threshold value, it means that the faulty port returns to normal.

The following is a detailed description of the working state of the DC solid-state circuit breaker circuit topology when the external DC circuit fails in conjunction with Figure 3. When the external DC microgrid and power distribution system fail, for example, a short-circuit fault occurs in the branch where the third port is located, the currents from other ports will flow into the faulty port, and the fault current will rise rapidly. When the system's detection device detects a DC short-circuit fault at the third port, the first auxiliary switch and the third selection switch simultaneously give conduction signals, and the positive and negative voltages on the capacitor C ₁ will be added to the third main current branch. on semi-controlled power electronic devices.

As shown in Figure 4, when the semi-controlled power electronic device of the third main current branch withstands the reverse voltage for longer than the inherent turn-off time, the third main current branch is disconnected and the fault current continues to reverse the direction of capacitor C1. Charge until the clamping voltage of the arrester MOV is reached. Then the arrester MOV is connected to the system and consumes the voltage and current in the system. The arrester MOV consumes the voltage and current in the system and turns off the first auxiliary switch. At the same time, the current of the third selection switch is less than the maintenance value. Naturally disconnected when current flows. Specifically, if the first auxiliary switch is a fully controlled power electronic device, the detection device detects that the current drops to the threshold and artificially disconnects the first auxiliary switch; if the first auxiliary switch is a semi-controlled power electronic device, the passing current After the current is less than the current that maintains its closure, the first auxiliary switch automatically opens.

After the fault is dealt with, turn off the first auxiliary switch. The current flowing through the jth selection switch is less than its maintaining current and then naturally turns off. Close the second auxiliary switch so that the second auxiliary switch is continuously turned on and the capacitor C1 is charged to DC. bus voltage, when the voltage of capacitor C1 is charged to the DC bus voltage, turn off the second auxiliary switch, and then give the jth selection switch conduction signal, capacitor C1 discharges to the jth port where the faulty DC circuit is detected, and the jth Whether the current peak value and voltage peak value of the port reach the threshold value. If it reaches the threshold value, whether the faulty port returns to normal; if it does not reach the threshold value, the faulty port does not return to normal state. The threshold can be set manually, and different circuit conditions have different thresholds.

As shown in Figure 5, after the fault is resolved, port 1 and port 2 can resume normal power supply, continuously conduct the signal to the gate of the second auxiliary switch, charge the capacitor C1, charge the voltage of the capacitor C1 to the DC system voltage, and then remove the The conduction signal of the second auxiliary switch is then turned on to the third selection switch, and the capacitor C1 discharges to the faulty 3rd port. It is judged whether the current peak value and voltage peak value of the 3rd port reach the threshold value. If they reach the threshold value, whether the faulty port returns to normal; If the threshold is not reached, the faulty port has not returned to normal. The threshold can be set manually, and different circuit conditions have different thresholds.

The discharge current path on R1 is ignored because R2 is much smaller than R1. Among them, the peak value of the load current is lower and the peak value of the load voltage is higher in the case of temporary fault compared with the permanent fault.

When the multi-port DC solid-state circuit breaker topology of the present invention is disconnected, the influence of the leakage current on the arrester MOV is completely eliminated, thereby solving the safety problem of the MOV. The invention solves the existing unreliable reclosing problem of the active back-pressure shutdown topology structure for semi-controlled power electronic devices. It can charge the capacitor C1 when the main current branch of the fault port is not conductive, and has the advantages Soft reclosing function.

As shown in Figure 6, a specific structure of the circuit topology of a semi-controlled DC solid-state circuit breaker is given, in which the first main current branch to the nth main current branch are composed of thyristors connected in anti-parallel. The first to n-th selection switches are composed of unidirectional thyristors, and the first auxiliary switch and the second auxiliary switch also use thyristors. Among them, all selection switches are composed of one-way semi-controlled power electronic devices; all main flow branches are composed of low-loss semi-controlled power electronic devices in anti-parallel connection. The first auxiliary switch is composed of a one-way semi-controlled power electronic device or a one-way fully controlled power electronic device, and the second auxiliary switch is composed of a one-way semi-controlled power electronic device.

When the multi-port DC solid-state circuit breaker topology is disconnected, the influence of the leakage current on the arrester is completely eliminated, thereby solving the safety problem of the arrester. The invention solves the existing unreliable reclosing problem of the active back-pressure shutdown topology structure for semi-controlled power electronic devices. It can charge the capacitor C1 when the main current branch of the fault port is not conductive, and has the advantages Soft reclosing function.

Although each step is described in the above-mentioned order in the above embodiment, those skilled in the art can understand that in order to achieve the effects of this embodiment, different steps do not have to be executed in such an order, and they can be performed at the same time ( Parallel) execution or execution in reverse order, these simple changes are within the scope of the present invention.

It should be noted that the semi-controlled DC solid-state circuit breaker circuit topology provided by the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be allocated to different modules as needed. Functional modules are used to complete the process, that is, the modules or steps in the embodiments of the present invention are decomposed or combined. For example, the modules of the above embodiments can be combined into one module, or can be further divided into multiple sub-modules to complete all of the above descriptions or Some functions. The names of the modules and steps involved in the embodiments of the present invention are only used to distinguish each module or step and are not regarded as improper limitations of the present invention.

An electronic device according to a third embodiment of the present invention includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions that can be executed by the processor, and the instructions are used to be executed by the processor. To realize the above-mentioned DC solid-state circuit breaker circuit topology based on semi-controlled devices.

A fourth embodiment of the present invention is a computer-readable storage medium. The computer-readable storage medium stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned semi-controlled DC solid-state circuit breaker circuit topology.

Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes and related descriptions of the above-described storage device and processing device can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. Repeat.

Those skilled in the art should be able to realize that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software, or a combination of both, and the programs corresponding to the software modules and method steps Can be placed in random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other device known in the art. any other form of storage media. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described according to function in the above description. Whether these functions are performed as electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementations should not be considered to be beyond the scope of the present invention.

The terms "first", "second", etc. are used to distinguish similar objects, but are not used to describe or indicate a specific order or sequence.

The term "comprising" or any other similar term is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus/apparatus including a list of elements includes not only those elements but also other elements not expressly listed, or Also included are elements inherent to such processes, methods, articles or equipment/devices.

So far, the technical solution of the present invention has been described with reference to the preferred embodiments shown in the drawings. However, those skilled in the art can easily understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or replacements to relevant technical features, and the technical solutions after these changes or replacements will fall within the protection scope of the present invention.

Claims (3)

1. A DC solid-state circuit breaker circuit topology based on semi-controlled devices. The DC solid-state circuit breaker topology includes: DC system, first auxiliary switch, second auxiliary switch, arrester MOV, capacitor C1 and auxiliary branch; The first end of the DC system, the second end of the arrester, the second end of the first auxiliary switch and the second end of the second auxiliary switch are connected to the first node G1; the first end of the second auxiliary switch, the first end of the arrester terminal and the second terminal of the capacitor C1 are connected to the second node G2; the first terminal of the capacitor C1, the first terminal of the first auxiliary switch and the second terminal of the auxiliary branch are connected to the third node G3; the first terminal of the auxiliary branch One end is grounded through the fourth node G4; The DC system includes n selection switches, n main flow branches and n ports; The auxiliary branch includes: a first resistor R1, a second resistor R2 and a diode D1; The second end of the auxiliary branch, the diode D1 and the first resistor R1 are connected to the third node G3. The end of the diode D1 close to the third node G3 is the cathode of the diode D1; the diode D1 and the second resistor R2 are connected in series, and the diode D1 is close to the third node G3. One end of the two resistors R2 is the anode of the diode; the first end of the auxiliary branch, the first resistor R1 and the second resistor R2 are connected to the fourth node G4; The DC system includes n parallel DC subsystems, n is a positive integer; The first end of each DC subsystem is connected to the first end of the DC system, and the second end of each DC subsystem is connected to the second end of the DC system; each DC subsystem includes a main current branch and a selection switch. and a port; The first end of the i-th DC subsystem is connected to the first end of the i-th main flow branch, the second end of the i-th DC subsystem is connected to the second end of the i-th selector switch, and the i-th main flow branch is connected to the second end of the i-th main flow branch. The two ends are connected to the i-th port, i is the serial number corresponding to any DC subsystem, and the value range of i is any integer from 1 to n; The first auxiliary switch is composed of a one-way semi-controlled power electronic device or a one-way fully controlled power electronic device, and the second auxiliary switch is composed of a one-way semi-controlled power electronic device; All selector switches are composed of one-way semi-controlled power electronic devices; all main current branches are composed of low-loss semi-controlled power electronic devices in anti-parallel connection; When the external DC circuit connected to the DC solid-state circuit breaker circuit topology is operating normally, the selector switches 1 to n are in the off state, the first auxiliary switch is in the off state, the second auxiliary switch is continuously on, and the capacitor C ₁ is charged to the DC bus voltage. 2. A method for controlling the circuit topology of a DC solid-state circuit breaker based on a semi-controlled device, characterized in that it operates based on the circuit topology of a DC solid-state circuit breaker based on a semi-controlled device according to claim 1; When the external DC circuit connected by the DC solid-state circuit breaker circuit topology based on the semi-controlled device operates normally, the selector switches 1 to n are in the off state, the first auxiliary switch is in the off state, the second auxiliary switch is continuously on, and the capacitor C ₁ is charged to the DC bus voltage. When the voltage of capacitor C ₁ is charged to the DC system voltage, the second auxiliary switch is turned off; When a short-circuit fault occurs in an external DC circuit connected to the DC solid-state circuit breaker circuit topology based on semi-controlled devices, the detection device detects an abnormal increase in current at the j-th port of the faulty DC circuit, and provides the j-th selector switch and the first auxiliary switch. When the signal is turned on, the fault current reversely charges the capacitor C ₁ until it reaches the clamping voltage of the arrester MOV. The arrester is triggered. The triggered arrester MOV consumes the voltage and current in the system, so that the current of the external circuit connected to the jth port is always at Under the safety threshold, j is the serial number of the DC subsystem corresponding to the external DC circuit where a short-circuit fault occurs. 3. The control method of the DC solid-state circuit breaker circuit topology based on the semi-controlled device according to claim 2, characterized in that the control method further includes: After the fault is handled, turn off the first auxiliary switch. The current flowing through the jth selector switch is less than its maintaining current and then naturally turns off. Close the second auxiliary switch so that the second auxiliary switch is continuously turned on and the capacitor C ₁ is charged to DC bus voltage, when the voltage of capacitor C ₁ is charged to the DC bus voltage, the second auxiliary switch is turned off, and then the j-th selection switch conduction signal is given, and capacitor C ₁ discharges to the j-th port where the faulty DC circuit is detected, Determine whether the current peak value and voltage peak value of the j-th port reach the threshold value. If the current peak value reaches the first threshold value and the voltage peak value reaches the second threshold value, it indicates a fault.