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

Abstract

This invention proposes a DC solid-state circuit breaker topology and control method based on fully controllable bidirectional devices, relating to the field of electronic circuits. It includes a main conducting branch and a shared energy-absorbing branch, wherein the main conducting branch and the shared energy-absorbing branch are electrically connected. The main conducting branch comprises n parallel dominant electronic branches; the shared energy-absorbing branch includes an auxiliary switch, a surge arrester, and 2n diodes. One end of the auxiliary switch is connected to the cathode of diode D1, the cathode of diode D3, ... and diode D... 2n‑1 The negative terminal of the circuit breaker is connected, and the other end of the auxiliary switch is connected to one end of the surge arrester. The other end of the surge arrester is connected to the positive terminal of diode D2, the positive terminal of diode D4, ... and diode D... 2n The positive terminal of diode D1 is connected, and the common terminal of diode D2 is electrically connected to the first dominant electronic branch. 2n‑1 With diode D 2n The common terminal is electrically connected to the nth dominant electronic branch. This application helps to improve the power density of DC solid-state circuit breakers and reduce high conduction losses.

Description

Technical Field

[0001] This invention relates to the field of electronic circuits, and in particular to a DC solid-state circuit breaker topology and control method based on a fully controllable bidirectional device. Background Technology

[0002] In recent years, with the widespread deployment of clean energy sources such as wind and solar power, and the rapid development of new energy storage materials such as lithium iron phosphate and power electronics technology, the penetration rate of renewable energy in the power system has continued to increase. At the same time, social electricity demand has shown a diversified and high-quality trend, and users' requirements for power quality, safety, reliability, and economy have been continuously increasing, promoting the deep integration of distributed power sources and energy storage devices. Moreover, with the rapid development of power electronics technology, the load structure has also undergone significant changes. In actual engineering and life scenarios, most new energy power generation units and terminal loads, such as photovoltaic systems, fuel cells, electric vehicles, supercapacitors, laptops, and air conditioners, operate in DC mode. New DC loads such as big data centers have emerged on a large scale, and the load side has begun to gradually transform into a load structure dominated by DC loads.

[0003] Chinese Patent CN116865738B discloses a DC solid-state circuit breaker circuit topology and control method based on semi-controlled devices. The topology includes a DC system, a surge arrester, a first auxiliary switch, and a second auxiliary switch connected to a first node G1; a second auxiliary switch, a surge arrester, and a capacitor C1 connected to a second node G2; a capacitor C1, a first auxiliary switch, and an auxiliary branch connected to a third node G3; and an auxiliary branch grounded through a fourth node G4. However, this scheme requires two thyristors in anti-parallel connection for each port to achieve bidirectional switching, and the control strategy is complex, resulting in high conduction losses in the solid-state circuit breaker and insufficient power density. Therefore, providing a DC solid-state circuit breaker topology and control method based on fully controlled bidirectional devices is essential to improve the power density and reduce high conduction losses. Summary of the Invention

[0004] In view of this, the present invention proposes a DC solid-state circuit breaker topology and control method based on fully controllable bidirectional devices. Each single bidirectional switch in the main conductive branch can achieve conduction and cutoff in both forward and reverse directions. Simultaneously, the shared energy-absorbing branch achieves centralized absorption and shunting of multiple fault energies through an auxiliary switch, a surge arrester, and 2n diodes, which helps to improve the power density of the DC solid-state circuit breaker and reduce high conduction losses.

[0005] This invention provides a DC solid-state circuit breaker topology based on fully controlled bidirectional devices, including a main conducting branch and a shared energy-absorbing branch, wherein,

[0006] The main conductive branch is electrically connected to the shared energy-absorbing branch. The main conductive branch includes n parallel dominant electronic branches. Each dominant electronic branch includes a monolithic bidirectional switch, an inductor, and a port connected in sequence. The first terminal of the monolithic bidirectional switch of each dominant electronic branch is electrically connected to the first terminal of the monolithic bidirectional switches of the other dominant electronic branches. The dominant electronic branch is used to conduct bidirectionally with the port and disconnect from the port when the port fails. Here, n is a positive integer.

[0007] The shared energy-absorbing branch includes an auxiliary switch, a surge arrester, and 2n diodes. One end of the auxiliary switch is connected to the cathode of diode D1, the cathode of diode D3, ..., and diode D... 2n-1 The negative terminal of the auxiliary switch is connected to one end of the surge arrester, and the other end of the surge arrester is connected to the positive terminal of diode D2, the positive terminal of diode D4, ... and diode D... 2n The positive terminal of diodes D1 and D2 is connected to the first dominant electron branch, and the common terminal of diodes D3 and D4 is connected to the second dominant electron branch. 2n-1 With the diode D 2n The common terminal is electrically connected to the nth dominant electronic branch.

[0008] Based on the above technical solutions, preferably, the first end of each dominant electronic branch is electrically connected to the first end of the other dominant electronic branches, and the second end of each dominant electronic branch is electrically connected to the port corresponding to the current dominant electronic branch.

[0009] The i-th dominant electronic branch includes a monolithic bidirectional switch S. i Inductor L i And the i-th port, a single-chip bidirectional switch S i One end is connected to single-chip bidirectional switch S1, single-chip bidirectional switch S2, ... and single-chip bidirectional switch S... n Electrical connection, the single-chip bidirectional switch S i With the inductor L i The common terminal of the diode D 2i-1 With the diode D 2i The common terminal is electrically connected, and the inductor L i The other end is electrically connected to the i-th port, where i represents the index of any dominant electronic branch, and the value of i is any integer from 1 to n.

[0010] Based on the above technical solutions, preferably, the DC solid-state circuit breaker topology includes a normal operation state, a fault occurrence state, a fault current absorption state, a fault recovery state, and a standby protection state, wherein,

[0011] If a port fault exists in the DC solid-state circuit breaker topology, the DC solid-state circuit breaker topology will sequentially enter the normal operation state, the fault occurrence state, the fault current absorption state, and the fault recovery state.

[0012] If the DC solid-state circuit breaker topology has a single bidirectional switch fault, the DC solid-state circuit breaker topology will sequentially enter the normal operation state, the fault occurrence state, the standby protection state, and the fault recovery state.

[0013] More preferably, in the normal operating state, the single bidirectional switch of each dominant electronic branch is closed, and the power supply terminal supplies power to the other dominant electronic branches through the port corresponding to the first dominant electronic branch. In the normal operating state, the main conductive branch is disconnected from the shared energy-absorbing branch.

[0014] More preferably, in the fault current absorption state, when the port corresponding to the dominant electronic branch other than the first dominant electronic branch is a fault port, the single bidirectional switch in the dominant electronic branch is disconnected.

[0015] The single-chip bidirectional switch in the main electronic branch corresponding to the fault port is disconnected. Except for the port in the main electronic branch corresponding to the fault port, the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port, so that the fault current is transferred from the main conductive branch to the shared energy-absorbing branch.

[0016] More preferably, in the fault recovery state, except for the main electronic branch corresponding to the faulty single-chip bidirectional switch, all the single-chip bidirectional switches of the other main electronic branches are opened. After the fault current drops to zero, the single-chip bidirectional switches of all the main electronic branches are closed in sequence, and the power supply terminal re-supply the port corresponding to the faulty single-chip bidirectional switch through the port corresponding to the first main electronic branch.

[0017] More preferably, in the standby protection state, except for the port of the main electronic branch corresponding to the fault port, all single-chip bidirectional switches in the other main electronic branches are disconnected, and the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diodes. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port.

[0018] When the fault current drops to zero, the auxiliary switch automatically turns off after its operating time reaches the closing time, and the port corresponding to the first main electronic branch re-energizes the fault port.

[0019] More preferably, the monolithic bidirectional switch is a silicon-based monolithic bidirectional power switch, and the auxiliary switch is a thyristor.

[0020] In another aspect, the present invention proposes a control method for a DC solid-state circuit breaker topology based on fully controllable bidirectional devices. The control method for the DC solid-state circuit breaker topology based on fully controllable bidirectional devices includes:

[0021] When the external DC circuit of the DC solid-state circuit breaker topology is working normally, all the monolithic bidirectional switches corresponding to the main electronic branches are in the closed state, and the auxiliary switches are in the open state.

[0022] When a short-circuit fault occurs in the external DC circuit of the DC solid-state circuit breaker topology, the detection device detects an abnormal rise in current at port j in the DC solid-state circuit breaker topology and sends a conduction signal to the auxiliary switch. The single-chip bidirectional switch in the dominant electronic branch corresponding to port j is disconnected. Except for the port corresponding to the dominant electronic branch, the ports of the other dominant electronic branches are connected to one end of the auxiliary switch through the corresponding diodes. The other end of the auxiliary switch is electrically connected to the fault port through a surge arrester and the diode corresponding to port j, so that the surge arrester consumes the voltage and current in the input shared energy absorption branch. Here, j is the sequence number of the dominant electronic branch corresponding to the external DC circuit that has experienced a short-circuit fault, and the value of j is any integer from 1 to n.

[0023] More preferably, the control method further includes:

[0024] When the monolithic bidirectional switch of the j-th dominant electronic branch fails, all monolithic bidirectional switches of the other dominant electronic branches except the one corresponding to the j-th monolithic bidirectional switch are opened. After the fault current drops to zero, all monolithic bidirectional switches of the dominant electronic branches are closed in sequence, and the power supply is restored to the port corresponding to the j-th dominant electronic branch through the port corresponding to the first dominant electronic branch.

[0025] The DC solid-state circuit breaker topology and control method based on fully controllable bidirectional devices provided by this invention have the following advantages over the prior art:

[0026] (1) Each single bidirectional switch in the main conductive branch can be turned on and off in both positive and negative directions, which not only ensures bidirectional power transmission under normal working conditions, but also can quickly disconnect at the moment of port fault, with fast response speed. Furthermore, it adopts n parallel main electronic branches, each of which bears a part of the current, realizing the equal distribution of current. The parallel structure improves the overall current capacity. A single branch fault will not cause the whole machine to fail. At the same time, the shared energy absorption branch realizes the concentrated absorption and diversion of multiple fault energy through an auxiliary switch, a surge arrester and 2n diodes, which greatly reduces the number of devices, space occupation and cost. Only one auxiliary switch can control the on and off of the entire shared energy absorption branch. With the bidirectional switches of each parallel branch working together, the complexity of the control logic and drive circuit is simplified, which helps to improve the power density of the DC solid circuit breaker and reduce high conduction loss. It can also be seamlessly expanded without changing the main control structure.

[0027] (2) Real-time current monitoring can capture the abnormal current rise at port j at the moment of the fault and immediately disconnect the bidirectional switch of the main branch corresponding to the port to achieve microsecond-level isolation of the fault branch and prevent the fault current from expanding further. During normal operation, all bidirectional switches of the main electronic branches are closed and the auxiliary switches are disconnected to completely isolate the shared energy-absorbing branches, eliminating the extra conduction path and parasitic losses brought by the auxiliary energy-absorbing circuit and absorbing fault energy in a concentrated and efficient manner. After the fault occurs, only one auxiliary switch needs to be closed to combine each healthy branch to the arrester channel through the diode, reducing the number of distributed energy-absorbing elements and improving the energy discharge efficiency. At the same time, the main branch and the auxiliary energy-absorbing branch do not interfere with each other under normal / fault conditions, avoiding the safety hazards of mis-conduction or mis-absorbing energy. The fault energy is evenly distributed to each healthy branch diode and then borne by a single arrester, reducing the risk of unit overload. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The topology diagram of the DC solid-state circuit breaker based on fully controlled bidirectional devices provided by the present invention;

[0030] Figure 2 A schematic diagram of the DC solid-state circuit breaker topology under normal operating conditions provided by the present invention;

[0031] Figure 3 A schematic diagram of the DC solid-state circuit breaker topology under fault conditions provided by the present invention;

[0032] Figure 4 A schematic diagram of the DC solid-state circuit breaker topology in fault current absorption state provided by the present invention;

[0033] Figure 5 A schematic diagram of the DC solid-state circuit breaker topology in fault recovery state provided by the present invention;

[0034] Figure 6 A schematic diagram of the DC solid-state circuit breaker topology in standby protection mode provided by the present invention;

[0035] Figure 7 Timing diagrams of switching actions for fault clearing mode and backup protection mode provided by the present invention;

[0036] Figure 8 This is a schematic diagram of the theoretical current waveform during a short-circuit fault at the third port, as provided by the present invention. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention discloses a DC solid-state circuit breaker topology based on fully controlled bidirectional devices, with reference to... Figure 1 The aforementioned DC solid-state circuit breaker topology includes a main conducting branch and a shared energy-absorbing branch, wherein,

[0039] The main conductive branch is electrically connected to the shared energy-absorbing branch. The main conductive branch includes n parallel dominant electronic branches. Each dominant electronic branch includes a monolithic bidirectional switch, an inductor, and a port connected in sequence. The first terminal of the monolithic bidirectional switch of each dominant electronic branch is electrically connected to the first terminal of the monolithic bidirectional switches of the other dominant electronic branches. The dominant electronic branch is used to conduct bidirectionally with the port and disconnect from the port when the port fails. Here, n is a positive integer.

[0040] The shared energy-absorbing branch includes an auxiliary switch, a surge arrester, and 2n diodes. One end of the auxiliary switch is connected to the cathode of diode D1, the cathode of diode D3, ... and diode D... 2n-1 The negative terminal of the circuit breaker is connected, and the other end of the auxiliary switch is connected to one end of the surge arrester. The other end of the surge arrester is connected to the positive terminal of diode D2, the positive terminal of diode D4, ... and diode D... 2nThe positive terminals of diodes D1 and D2 are connected, and the common terminal of diodes D3 and D4 is connected to the first dominant electronic branch. The common terminal of diodes D3 and D4 is connected to the second dominant electronic branch. 2n-1 With diode D 2n The common terminal is electrically connected to the nth dominant electronic branch. The monolithic bidirectional switch is a silicon-based monolithic bidirectional power switch, and the auxiliary switch is a thyristor.

[0041] Furthermore, the first end of each dominant electronic branch is electrically connected to the first end of the other dominant electronic branches, and the second end of each dominant electronic branch is electrically connected to the port corresponding to the current dominant electronic branch.

[0042] The i-th dominant electronic branch includes a monolithic bidirectional switch S. i Inductor L i And the i-th port, a single-chip bidirectional switch S i One end is connected to single-chip bidirectional switch S1, single-chip bidirectional switch S2, ... and single-chip bidirectional switch S... n Electrical connection, single-chip bidirectional switch S i With inductor L i The common terminal and diode D 2i-1 With diode D 2i The common terminal electrical connection, inductor L i The other end is electrically connected to the i-th port, where i represents the index of any dominant electronic branch, and the value of i is any integer from 1 to n.

[0043] In this embodiment, the DC solid-state circuit breaker topology includes normal operation state, fault occurrence state, fault current absorption state, fault recovery state, and standby protection state.

[0044] In one example, the main conductive branch includes three parallel dominant electronic branches: the first dominant electronic branch, the second dominant electronic branch, and the third dominant electronic branch. The first dominant electronic branch includes a monolithic bidirectional switch S1, an inductor L1, and a first port; the second dominant electronic branch includes a monolithic bidirectional switch S2, an inductor L2, and a second port; and the third dominant electronic branch includes a monolithic bidirectional switch S3, an inductor L3, and a third port.

[0045] like Figure 2 As shown, under normal operating conditions, the single-chip bidirectional switch of each dominant electronic branch is closed, and the power supply provides power to the other dominant electronic branches through the port corresponding to the first dominant electronic branch. Under normal operating conditions, the main conductive branch is disconnected from the shared energy-absorbing branch. That is, if no fault occurs, the single-chip bidirectional switches S1-S3 are all closed, the power supply provides power to the other ports through the first port, and the shared energy-absorbing branch is disconnected from the DC solid-state circuit breaker topology.

[0046] like Figure 3 As shown, in the fault state, the single bidirectional switch of each main electronic branch is closed. When the port corresponding to any main electronic branch is a fault port, the fault current of the main electronic branch increases.

[0047] In one example, a short circuit fault occurs on the line of the third port, causing current to flow from the normal port to the faulty port, and the fault current in the third port rises rapidly.

[0048] like Figure 4 As shown, under fault current absorption state, when the port corresponding to the dominant electronic branch other than the first dominant electronic branch is a fault port, the single-chip bidirectional switch in the dominant electronic branch is disconnected.

[0049] The single-chip bidirectional switch in the main electronic branch corresponding to the fault port is disconnected. Except for the port in the main electronic branch corresponding to the fault port, the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port, so that the fault current is transferred from the main conductive branch to the shared energy absorption branch.

[0050] In one example, the monolithic bidirectional switch S3 corresponding to the third port opens, causing the first dominant electronic branch to stop supplying power to the port of the third dominant electronic branch. Simultaneously, the auxiliary switch Ta of the shared energy-absorbing branch closes, diverting the fault current to the shared energy-absorbing branch, forming a loop through the auxiliary switch Ta and the commutation diodes (D1, D3, D6). The voltage across the surge arrester MOV rapidly increases to its clamping voltage, and the fault current is absorbed by the surge arrester MOV, beginning to gradually decrease.

[0051] like Figure 5 As shown, in the fault recovery state, except for the main electronic branch corresponding to the faulty single-chip bidirectional switch, all the single-chip bidirectional switches of the other main electronic branches are opened. After the fault current drops to zero, the single-chip bidirectional switches of all main electronic branches are closed in sequence, and the power supply terminal re-supply the port corresponding to the faulty single-chip bidirectional switch through the port corresponding to the first main electronic branch.

[0052] In one example, in standby protection mode, if the monolithic bidirectional switch of the third dominant electronic branch fails to shut off normally, the fault current of the dominant branch can be cut off by shutting off the monolithic bidirectional switches of other healthy ports, thus achieving standby protection. After the fault is cleared, power supply can be restored by closing the monolithic bidirectional switches of the healthy ports.

[0053] like Figure 6As shown, in the standby protection state, except for the port of the main electronic branch corresponding to the fault port, all the single bidirectional switches in the other main electronic branches are open, and the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port.

[0054] When the fault current drops to zero, the auxiliary switch automatically shuts off after its operating time reaches the closing time, and the port corresponding to the first main electronic branch re-energizes the fault port.

[0055] In one example, during the recovery process, the surge arrester MOV continuously absorbs power supply energy and residual line inductance energy. After the fault energy is completely absorbed, the fault current drops to zero, the auxiliary switch Ta exits the blocking mode, and automatically turns off after its closing time. The fault interruption process is complete, and the first port resumes power supply to the third port.

[0056] In this embodiment, under normal operating conditions, all bidirectional switches of the main electronic branches are closed, with only the first branch operating and the other parallel branches isolated, avoiding circulating flow caused by uneven voltage and current between parallel branches. The shared energy-absorbing branch is completely disconnected, eliminating the additional conduction losses it introduces, resulting in the highest overall system efficiency. Under fault current absorption conditions, only the main switch corresponding to the fault port is disconnected, immediately isolating the faulty branch. Other healthy branches quickly connect in parallel with the shared energy-absorbing branch, and all fault currents are concentrated and discharged through the diode → auxiliary switch → surge arrester channel. This achieves rapid transfer and absorption of fault energy without triggering dedicated energy-absorbing devices for each branch, improving fault response speed and reducing hardware investment. Under fault recovery conditions, after the fault current returns to zero, the controller automatically shuts off the auxiliary switch, disconnects the shared energy-absorbing channel, and restores complete isolation between the main conductive branch and the energy-absorbing branch. The first branch automatically resumes power supply to the faulty port. The entire recovery process requires no manual intervention, shortening system downtime and ensuring rapid reconnection of the load after fault isolation. In standby protection mode, if the branch corresponding to the faulty port remains unrepaired for an extended period or experiences repeated faults, other parallel branches will sequentially reconnect and compensate for power supply until the faulty branch is repaired. The switching logic is simple and the sequence is clear, enabling load recovery with zero or minimal interruption time, thus enhancing system availability and redundancy.

[0057] If a port fault exists in the DC solid-state circuit breaker topology, the topology will sequentially enter the normal operation state, fault occurrence state, fault current absorption state, and fault recovery state. If a single bidirectional switch fault exists in the DC solid-state circuit breaker topology, the topology will sequentially enter the normal operation state, fault occurrence state, standby protection state, and fault recovery state.

[0058] like Figure 7 As shown, Figure 7 The diagram on the left shows the switching action timing diagram in fault clearing mode. Before t0, it is the normal operation stage. At this time, the single-cell bidirectional switches S1, S2, and S3 are all closed, and the auxiliary switch Ta is open. The DC solid-state circuit breaker topology is working normally, and bidirectional conduction is possible between each port. At time t1, a fault current is detected at the third port. The single-cell bidirectional switch S3 quickly opens to isolate the fault port. The single-cell bidirectional switches S1 and S2 remain closed, and the auxiliary switch Ta remains open. During the period from t1 to t2, the auxiliary switch Ta closes. The fault current is provided with a discharge path. The fault current flows into the surge arrester MOV through the auxiliary switch Ta and the corresponding diode and is absorbed. The single-piece bidirectional switches S1 and S2 remain closed, while the single-piece bidirectional switch S3 remains open. At time t2, the fault energy is completely absorbed by the surge arrester MOV, the fault current drops to zero, and the auxiliary switch Ta automatically exits the lockout and turns off. During the period from t2 to t3, the single-piece bidirectional switches S1, S2, and S3 all reclose, the auxiliary switch Ta remains open, and the DC solid-state circuit breaker topology returns to normal operation mode.

[0059] Figure 7 The diagram on the right is a timing diagram of the switching action in the standby protection mode. Before t0, the system is in normal operation. During this period, single-pole bidirectional switches S1, S2, and S3 are all closed, while auxiliary switch Ta is open. The DC solid-state circuit breaker topology is operating normally, and bidirectional conduction is possible between all ports. At t1, a switch fault is detected at the third port, meaning that single-pole bidirectional switch S3 cannot open normally. This triggers the backup protection mode, disconnecting all healthy ports. Due to the switch fault, single-pole bidirectional switch S3 remains in a certain state. From t1 to t2, auxiliary switch Ta closes, establishing an energy discharge path. By disconnecting all healthy ports, the faulty main circuit is cut off, and the fault energy is absorbed through auxiliary switch Ta and surge arrester MOV. At t2, auxiliary switch Ta automatically turns off, and the fault energy is completely absorbed. From t2 to t3, single-pole bidirectional switch S3 closes again, while single-pole bidirectional switches S1 and S2 remain open to ensure safety. From t3 to t4, after confirming that the fault has been completely cleared, single-pole bidirectional switches S1 and S2 close again, restoring power supply to all healthy ports. The DC solid-state circuit breaker topology returns to normal operation.

[0060] like Figure 8 As shown, Figure 8 This is the theoretical current waveform diagram for a short-circuit fault at the third port. Before t1, the current I at the third port is... S3 At the normal operating current level, the DC solid-state circuit breaker topology is in normal operating condition; at time t1, the third port is short-circuited, and the current I... S3The current begins to rise sharply, marking the starting point of the fault current, corresponding to the moment when the monolithic bidirectional switch S3 in the timing diagram begins to open; during the period t1 to t2, the current I... S3 The fault current exhibits a rapidly rising slope, reaching its peak value. At this point, the single-chip bidirectional switch S3 is open, and the auxiliary switch Ta is closed. The fault current begins to transfer to the surge arrester MOV via the auxiliary switch Ta and the corresponding diode. At time t2, the current I... S3 The maximum fault current value is reached, corresponding to the moment when auxiliary switch Ta in the timing diagram begins to unblock; after t2, the current I... S3 The current I drops rapidly to zero. S3 The MOV completely absorbed the fault energy, and the fault current was successfully cut off.

[0061] In this embodiment, each single bidirectional switch in the main conductive branch can be turned on and off in both forward and reverse directions, ensuring bidirectional power transmission under normal operating conditions and rapid disconnection in the event of a port fault, resulting in a fast response speed. Furthermore, the use of n parallel main electronic branches, each of which carries a portion of the current, achieves current distribution. The parallel structure increases the overall current capacity, and a single branch fault will not cause the entire unit to fail. Meanwhile, the shared energy-absorbing branch achieves centralized absorption and diversion of multiple fault energy sources through an auxiliary switch, a surge arrester, and 2n diodes, significantly reducing the number of components, space occupation, and cost. Only one auxiliary switch is needed to control the on / off state of the entire shared energy-absorbing branch. Working in conjunction with the bidirectional switches of each parallel branch, the complexity of the control logic and drive circuit is simplified, which helps to improve the power density of the DC solid-state circuit breaker and reduce high conduction losses. Seamless capacity expansion can also be performed without changing the main control structure.

[0062] The second embodiment of the present invention proposes a control method for a DC solid-state circuit breaker topology based on fully controllable bidirectional devices. The control method for the DC solid-state circuit breaker topology based on fully controllable bidirectional devices includes:

[0063] When the external DC circuit of the DC solid-state circuit breaker topology is working normally, all the monolithic bidirectional switches corresponding to the main electronic branches are in the closed state, and the auxiliary switches are in the open state.

[0064] When a short-circuit fault occurs in the external DC circuit of the DC solid-state circuit breaker topology, the detection device detects an abnormal rise in the current at port j in the DC solid-state circuit breaker topology and sends a conduction signal to the auxiliary switch. The single-chip bidirectional switch in the main electronic branch corresponding to port j is opened. Except for the port corresponding to the main electronic branch, the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to port j, so that the surge arrester consumes the voltage and current in the input shared energy absorption branch. Here, j is the sequence number of the main electronic branch corresponding to the external DC circuit that has experienced a short-circuit fault, and the value of j is any integer from 1 to n.

[0065] Furthermore, when the monolithic bidirectional switch of the j-th dominant electronic branch fails, all monolithic bidirectional switches of the other dominant electronic branches except the dominant electronic branch corresponding to the j-th monolithic bidirectional switch are opened. After the fault current drops to zero, the monolithic bidirectional switches of all dominant electronic branches are closed in sequence, and the power supply terminal re-supply the port corresponding to the j-th dominant electronic branch through the port corresponding to the first dominant electronic branch.

[0066] In this embodiment, real-time current monitoring can detect the abnormal current rise at port j at the moment of fault. The corresponding bidirectional switch of the main branch is immediately disconnected via a control signal, achieving microsecond-level isolation of the faulty branch and preventing further expansion of the fault current. During normal operation, all bidirectional switches of the main electronic branches are closed, auxiliary switches are open, and the shared energy-absorbing branches are completely isolated. This eliminates the additional conduction paths and parasitic losses caused by the auxiliary energy-absorbing circuits, ensuring the system's highest efficiency under normal operating conditions. Centralized and efficient fault energy absorption: After a fault occurs, only one auxiliary switch needs to be closed to connect all healthy branches to the surge arrester channel via diodes. The surge arrester absorbs most of the overvoltage and overcurrent energy; the centralized design reduces the number of distributed energy-absorbing elements and improves energy discharge efficiency. Only two control signals are required: the disconnect signal of the main switch corresponding to the faulty port and the closing signal of the auxiliary switch. Individual driving of each energy-absorbing branch or each diode is not required, simplifying the drive circuit and control algorithm. The main branch and the auxiliary energy-absorbing branch do not interfere with each other under normal / fault conditions, avoiding the safety hazards of mis-conduction or mis-absorbing energy; the fault energy is evenly distributed to the diodes of each healthy branch, and then borne by a single surge arrester, reducing the risk of unit overload.

[0067] Although the steps in the above embodiments are described in the above order, those skilled in the art will understand that in order to achieve the effect of this embodiment, different steps do not need to be executed in such an order. They can be executed simultaneously (in parallel) or in a reverse order. These simple variations are all within the protection scope of this invention.

[0068] It should be noted that the semi-controlled DC solid-state circuit breaker circuit topology provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be further decomposed or combined. For example, the modules in the above embodiments can be merged into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the various modules or steps and are not considered as an improper limitation of the present invention.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A DC solid-state circuit breaker topology based on fully controlled bidirectional devices, characterized in that, It includes the main conductive branch and the shared energy-absorbing branch, among which, The main conductive branch is electrically connected to the shared energy-absorbing branch. The main conductive branch includes n parallel dominant electronic branches. Each dominant electronic branch includes a monolithic bidirectional switch, an inductor, and a port connected in sequence. The first terminal of the monolithic bidirectional switch of each dominant electronic branch is electrically connected to the first terminal of the monolithic bidirectional switches of the other dominant electronic branches. The dominant electronic branch is used to conduct bidirectionally with the port and disconnect from the port when the port fails. Here, n is a positive integer. The shared energy-absorbing branch includes an auxiliary switch, a surge arrester, and 2n diodes. One end of the auxiliary switch is connected to the cathode of diode D1, the cathode of diode D3, ..., and diode D... 2n-1 The negative terminal of the auxiliary switch is connected to one end of the surge arrester, and the other end of the surge arrester is connected to the positive terminal of diode D2, the positive terminal of diode D4, ... and diode D... 2n The positive terminal of diodes D1 and D2 is connected to the first dominant electron branch, and the common terminal of diodes D3 and D4 is connected to the second dominant electron branch. 2n-1 With the diode D 2n The common terminal is electrically connected to the nth dominant electronic branch; The DC solid-state circuit breaker topology includes normal operation state, fault occurrence state, fault current absorption state, fault recovery state, and standby protection state, wherein, If a port fault exists in the DC solid-state circuit breaker topology, the DC solid-state circuit breaker topology will sequentially enter the normal operation state, the fault occurrence state, the fault current absorption state, and the fault recovery state. If the DC solid-state circuit breaker topology has a single bidirectional switch fault, the DC solid-state circuit breaker topology will sequentially go through the normal operation state, the fault occurrence state, the standby protection state, and the fault recovery state. In the normal operating state, the single bidirectional switch of each dominant electronic branch is closed, and the power supply terminal supplies power to the other dominant electronic branches through the port corresponding to the first dominant electronic branch. In the normal operating state, the main conductive branch is disconnected from the shared energy-absorbing branch. Under the fault current absorption state, when the port corresponding to the dominant electronic branch other than the first dominant electronic branch is a fault port, the single-chip bidirectional switch in the dominant electronic branch is disconnected. The single-chip bidirectional switch in the main electronic branch corresponding to the fault port is disconnected. Except for the port in the main electronic branch corresponding to the fault port, the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port, so that the fault current is transferred from the main conductive branch to the shared energy-absorbing branch. In the standby protection state, except for the port of the main electronic branch corresponding to the fault port, all single-chip bidirectional switches in the other main electronic branches are disconnected, and the ports of the other main electronic branches are connected to one end of the auxiliary switch through the corresponding diode. The other end of the auxiliary switch is electrically connected to the fault port through the surge arrester and the diode corresponding to the fault port. When the fault current drops to zero, the auxiliary switch automatically turns off after its operating time reaches the closing time, and the port corresponding to the first main electronic branch re-energizes the fault port.

2. The DC solid-state circuit breaker topology based on fully controlled bidirectional devices as described in claim 1, characterized in that, The first end of each dominant electronic branch is electrically connected to the first end of the other dominant electronic branches, and the second end of each dominant electronic branch is electrically connected to the port corresponding to the current dominant electronic branch. The i-th dominant electronic branch includes a monolithic bidirectional switch S. i Inductor L i And the i-th port, a single-chip bidirectional switch S i One end is connected to single-chip bidirectional switch S1, single-chip bidirectional switch S2, ... and single-chip bidirectional switch S... n Electrical connection, the single-chip bidirectional switch S i With the inductor L i The common terminal of the diode D 2i-1 With the diode D 2i The common terminal is electrically connected, and the inductor L i The other end is electrically connected to the i-th port, where i represents the index of any dominant electronic branch, and the value of i is any integer from 1 to n.

3. The DC solid-state circuit breaker topology based on fully controlled bidirectional devices as described in claim 2, characterized in that, In the fault recovery state, except for the main electronic branch corresponding to the faulty single-chip bidirectional switch, all single-chip bidirectional switches of the other main electronic branches are opened. After the fault current drops to zero, the single-chip bidirectional switches of all main electronic branches are closed in sequence, and the power supply terminal re-supply the port corresponding to the faulty single-chip bidirectional switch through the port corresponding to the first main electronic branch.

4. The DC solid-state circuit breaker topology based on fully controlled bidirectional devices as described in claim 1, characterized in that, The monolithic bidirectional switch is a silicon-based monolithic bidirectional power switch, and the auxiliary switch is a thyristor.

5. A control method for a DC solid-state circuit breaker topology based on fully controllable bidirectional devices, operating based on the DC solid-state circuit breaker topology based on fully controllable bidirectional devices according to any one of claims 1-4, characterized in that, The control method includes: When the external DC circuit of the DC solid-state circuit breaker topology is working normally, all the monolithic bidirectional switches corresponding to the main electronic branches are in the closed state, and the auxiliary switches are in the open state. When a short-circuit fault occurs in the external DC circuit of the DC solid-state circuit breaker topology, the detection device detects an abnormal rise in current at port j in the DC solid-state circuit breaker topology and sends a conduction signal to the auxiliary switch. The single-chip bidirectional switch in the dominant electronic branch corresponding to port j is disconnected. Except for the port corresponding to the dominant electronic branch, the ports of the other dominant electronic branches are connected to one end of the auxiliary switch through the corresponding diodes. The other end of the auxiliary switch is electrically connected to the fault port through a surge arrester and the diode corresponding to port j, so that the surge arrester consumes the voltage and current in the input shared energy absorption branch. Here, j is the sequence number of the dominant electronic branch corresponding to the external DC circuit that has experienced a short-circuit fault, and the value of j is any integer from 1 to n.

6. The control method for a DC solid-state circuit breaker topology based on a fully controllable bidirectional device as described in claim 5, characterized in that, The control method further includes: When the monolithic bidirectional switch of the j-th dominant electronic branch fails, all monolithic bidirectional switches of the other dominant electronic branches except the one corresponding to the j-th monolithic bidirectional switch are opened. After the fault current drops to zero, all monolithic bidirectional switches of the dominant electronic branches are closed in sequence, and the power supply is restored to the port corresponding to the j-th dominant electronic branch through the port corresponding to the first dominant electronic branch.

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