Direct-current micro-grid and assemblies thereof

Abstract

The present invention relates to a direct-current micro-grid and assemblies thereof, and particularly relates to a direct-current micro-grid having a wide application range and high safety. The direct-current micro-grid comprises a first main line and a second main line, wherein the first main line is used for power supply, and the second main line is used for arc extinction. The present invention has a rational design, and has the advantages of a wide application range and high safety.

Description

DC micro-grid and components thereof TECHNICAL FIELD

[0001] The present application relates to a DC micro-grid and components thereof, in particular to a DC micro-grid with wide application range and high safety and components convenient to use. BACKGROUND

[0002] The DC power grid has the advantages of small loss and high transmission efficiency, but due to the absence of zero point in DC, the safety problem caused by the arc is difficult to handle, and the arc problem of switches and connectors is one of the technical bottlenecks that current DC power distribution is difficult to popularize in buildings and other places. The current traditional DC power distribution network is difficult to meet the safety requirements. SUMMARY

[0003] The purpose of the present application is to solve the problems mentioned in the background art and provide a DC micro-grid with wide application range and high safety and components convenient to use.

[0004] The purpose of the present application is achieved by the following technical solutions:

[0005] A DC micro-grid, as shown in FIG. 1, includes a trunk line V1 (first trunk line) and a trunk line V2 (second trunk line), the trunk line V1 is used for power supply, and the trunk line V2 is used for arc extinguishing.

[0006] Working principle: the trunk line V2 is connected to a pulse power supply, and the pulse current is used to realize arc extinguishing for the device connected to the trunk line V2.

[0007] The present application has the advantages of wide application range and high safety. BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a principle diagram of the DC micro-grid of the present application.

[0009] FIG. 2 is a principle diagram of one of the embodiments of the DC micro-grid and components thereof of the present application.

[0010] FIG. 3 is a principle diagram of another of the embodiments of the DC micro-grid and components thereof of the present application.

[0011] FIG. 4 is a principle diagram of a connection device of the DC micro-grid of the present application.

[0012] FIG. 5 is a principle diagram of another connection device of the DC micro-grid of the present application.

[0013] FIG. 6 is a principle diagram of one of the embodiments of the DC micro-grid of the present application.

[0014] FIG. 7 is a principle diagram of another of the embodiments of the DC micro-grid of the present application.

[0015] FIG. 8 is a principle diagram of another of the embodiments of the DC micro-grid of the present application.

[0016] Figure 9 is a schematic diagram of a display unit of a DC microgrid embodiment of the present application.

[0017] Figure 10 is a schematic diagram of a control device of a DC microgrid and its components embodiment of the present application. DETAILED DESCRIPTION

[0018] Embodiments of the present application:

[0019] As shown in Figures 2 and 3, a DC microgrid and its components, comprising a control device C (pulsed power supply), a trunk V1 (first trunk), a trunk V2 (second trunk), a connecting device (S1, S2, S3, S4, SC1, SC2, for establishing an electrical connection), a unidirectional device D (a semiconductor unidirectional conduction device, note: the unidirectional device D shown in Figure 3 is placed in the connecting device), the power (energy) of the trunk V1 (not limited) and the trunk V2 is provided by the total power supply V+ through the control device C (built-in switch), the trunk V2 arc extinguishes the connecting device, the electrode P1 (first electrode) of the connecting device is connected with the trunk V1, the electrode P2 (second electrode) of the connecting device is connected with the trunk V2 through the unidirectional device D, the electrodes P1, P2 and the load terminal P3 (electrode P3, third electrode; when the connecting device is a socket or a plug of a connector, P3 is an external plug or socket) form a break point K1 (first break point) and a break point K2 (second break point) between them, and each unidirectional device D is connected with the trunk V2 in common anode (note: in actual engineering applications, it can also be connected in common cathode according to the line requirements).

[0020] Working principle: the unidirectional device D and the electrode P2 form a selection switch, which realizes the isolation between each connecting device, when the connecting device is disconnected, the trunk V2 provides current to the electrode P2 through the unidirectional device D, so that the current through the break point K1 is reduced to zero, thereby realizing the arcless disconnection (or arc extinguishing) of the break point K1, then the control device C turns off the current of the trunk V2, realizes the arc extinguishing (or arcless disconnection) of the break point K2, completes the working process, and then the control device C provides the trunk V2 voltage (energy) again, preparing for the next working cycle.

[0021] Connection device (S1, S2, S3, S4, SC1, SC2): S1 is a bridging switch, electrode P2 is a contact bridge; S2 is a switch with a conventional linkage structure (Note: two double-blade switches are used in series, or two groups of bridging structure switches as shown in S1 can be used in series, the working principle is the same, the common node of the two series components is electrode P2), the break point K1 (contact point) formed by electrode P1 and electrode P2 of the connection device (S1, S2), and the break point K2 (contact point) formed by electrode P2 and the load end P3 constitute a series circuit, and the main line V1 is powered through the series circuit; S3 is a slidingly connected switch, S4 is a linkage switch, SC1 and SC2 are sockets (or plugs, slidingly connected, and when including the load end P3, they are connectors), and the working process is as follows: during the disconnection of the load end P3, the load end P3 is first disconnected from electrode P1 (break point K1 is generated, and arcless or micro-arc disconnection can be achieved), and then the load end P3 is disconnected from electrode P2 (break point K2 is generated, and arcless or micro-arc disconnection can be achieved when disconnected during the period when the main line V2 does not provide voltage); the connection device (S1, S2) is a synchronous disconnection connection device, and the connection device (S3, S4, SC1, SC2) is an asynchronous disconnection (K1 disconnects before K2 disconnects) connection device, and the asynchronous time of the connection device with the structure of S4 needs to be greater than the power-off time of the main line V2 (i.e. the time for the control device C to stop supplying power to the main line V2).

[0022] The control device C detects the disconnection of the connecting device by detecting the current of the trunk V2, detects the arc extinguishing action when the arc extinguishing current of the trunk V2 exists, that is, the arc extinguishing of the breaking point K1 has been realized, then the control device C closes the current of the trunk V2 to realize the arc extinguishing of the breaking point K2, and then provides power for the trunk V2 to perform the next working cycle, if the current is detected again, the previous working process is repeated, when the current of the trunk V2 is detected to exceed the set time range, it can be judged that the power grid is abnormal, and the power supply (or the total power supply V+) of the trunk V1 and the trunk V2 is turned off; the control device C can also be used to detect the voltage of the trunk V2 during the period when the control device C does not provide power for the trunk V2, which is used to detect whether the unidirectional device D has breakdown; the control device C is connected with the trunk V1 (preferably) for detecting the current and voltage of the trunk V1, when the control device C has the functions of detecting and controlling the trunk V1 and the trunk V2 at the same time, the accuracy of detecting the fault arc of the direct-current micro-grid can be greatly improved, and the safety of the direct-current micro-grid is further ensured; when the control device C has the functions of detecting the current (or voltage) of the trunk V1 and the current (or voltage) of the trunk V2 at the same time, it can also be used as follows: when the trunk V1 is powered off (the power-off defined in the present application is that the current is zero, or the voltage suddenly drops, which presents that the potential difference between the trunk V2 and the trunk V1 meets the conduction of the unidirectional device D), and the current of the trunk V2 appears (which presents that the potential difference between the trunk V2 and the trunk V1 meets the conduction of the unidirectional device D), it proves that the connecting device does not have arc, but the voltage transient of the trunk V1 (power-off) occurs, the power supply of the trunk V2 is maintained, which can effectively suppress the voltage transient (power-off) and prevent accidents of the load connected by the connecting device, when the two trunks (V1, V2) use the same power supply, the problem caused by the failure (such as disconnection, disconnection of the connecting device for supplying power to the trunk V1 for a short time due to mechanical impact) of the trunk V1 can be overcome, and the power supply independent of the trunk V1 can also be used to supply power to the trunk V2 through the control switch of the control device C.

[0023] As shown in FIG. 3, the direct-current micro-grid and its components of the building direct-current power distribution: it further includes a power distribution unit (box) U, the power distribution unit includes a control device C (arc extinguishing device), circuit breakers (B1, B2, respectively used for lighting and socket protection), the circuit breakers at least include a first pole switch L1 and a second pole switch L2, the trunk V1 is connected with the connecting device through the first pole switch L1, and the trunk V2 is connected with the common node of the unidirectional device D through the second pole switch L2; the control device C is used for detecting the leakage current and insulation resistance of the trunk V1, the trunk V2 and the power supply ground G to the ground E, the control device C is used for detecting the fault arc, and the trunk V2 is used for detecting the leakage current (insulation) of the connecting device, when the abnormality is detected, the power supply (or the total power supply V+) of the trunk V1 and the trunk V2 is turned off. As shown in FIG. 3, the control device C has more comprehensive functions, and the control device C can also be used in combination with FIG. 1, in actual engineering application, the function of the control device C can be simplified according to the requirements.

[0024] In this embodiment, the control device C shares the power supply with the trunk V1 (preferably), and uses the power supply V+ to pass through the internal semiconductor switch of the control device C, and then passes through the trunk V2 and the unidirectional device D to bypass (parallel) the arc extinguishing of the break point K1, and then in series with the arc extinguishing of the break point K2.

[0025] As shown in FIG. 3, the display unit LD is connected in parallel with the series circuit composed of the unidirectional device D and the electrode P1, and the display unit LD can refer to the circuit in FIG. 9, which is composed of the capacitor C1, the resistor RB (optional), and the display device (LED1, LED2) in series. The display unit LD can display the arc extinguishing process of the trunk V2, and the control device C can also output low-level pulses to the trunk V2 at intervals of several seconds to drive the display unit LD, which is used to display whether the connection device is normally connected to the trunk V2, thereby improving the safety. The display unit and the unidirectional device shown in FIG. 3 can also be used in the connection device in FIG. 2.

[0026] As the current 375V (800V) DC system, circuit breaker is used in multiple series, also can use the scheme of figure 4, trunk V2 through the second pole L2 switch (form the third break point K3, note: the first pole switch L1 and the third pole switch L3 are used in series, form break point K1, break point K2) and the one-way device D of the next level connection device connection; When the need for double control of load (such as lamp), can use the wiring scheme shown in figure 5 (the diode D of S1-2 shown in figure 5 can be cancelled, using the diode D of S1-1 can). The one-way device D shown in figure 2, figure 3, figure 4, figure 5 uses diode (non controlled device, can be multiple series, increase the conduction voltage threshold, or used to improve the reverse withstand voltage), the scheme not only has the advantages of simple wiring, good frequency characteristic (support higher frequency pulse arc extinguishing), strong overcurrent capacity, cost-effective, no leakage current, but also can use the trunk V2 to detect the break point between electrode P2 and trunk V1 (node V1) and the overcurrent fault of connection device (can be judged by detecting the duration of trunk V2 pulse current), when multiple dispersed layout connection device is in the on state, and the trunk V1 working current is large, the line voltage drop between the connection device connected to the end of the power grid and the power supply may cause current in the trunk V2, in order to prevent this phenomenon, it is recommended that the potential difference between the trunk V2 and the trunk V1 ensures that the one-way device D is reverse biased (the potential difference is the reverse bias voltage of the one-way device; the reverse bias voltage should be greater than the maximum working voltage drop allowed by the trunk V1, the highest allowable voltage drop value of the general standard is 5% of the supply voltage) when the break point K1 and the break point K2 of the connection device are in the on state, the reverse bias voltage value of the trunk V2 during current is less than (preferred, which is conducive to improving the arc extinguishing effect) or equal to the reverse bias voltage value of the trunk V2 during no current; When the one-way device D is replaced by thyristor (half controlled device), a number of elements or devices can be simply added, as shown in figure 6, figure 7, figure 8, the common anode connection of each thyristor D, as shown in figure 6 (note: similar technical effect as using non controlled device, both are two terminal selection switch composed of one-way device D and electrode P2, the difference is that it is easy to increase the conduction voltage threshold, and the conduction voltage threshold can be greater than the conduction voltage drop value), the control electrode of the thyristor D is connected with the anode (end) of the thyristor D through the resistance R (optional), the voltage detection device ZA (voltage stabilizing diode, optional), the diode DA (rectifier diode) (note: in addition, the diode DA can also be connected in series with the anode or cathode of the thyristor, and the control electrode of the thyristor is directly connected with the anode of the thyristor), the cathode of the thyristor is connected with the electrode P2, this scheme is used to overcome the false conduction of the one-way device (such as using non controlled device) caused by the voltage drop of the trunk V1 under special conditions; As shown in figure 7, the control electrode of the thyristor D is connected with the electrode P1 through the resistance R, and the electrode P2 is connected with the cathode of the thyristor D;As shown in FIG. 8, the control electrode of the thyristor D is connected to the electrode P2 through the resistor R, and the cathode of the thyristor D is connected to the load end P3. Compared with other schemes of the application, the key difference is that the main circuit of the unidirectional device D is not connected in series with the electrode P2. In the arc extinguishing process, the series circuit composed of the dry line V2, the unidirectional device D, the break K1 and the break K2 is bypassed (shunted) by the control device C to extinguish the arc. In addition, when the connecting device is subjected to external impact or voltage transient, the dry line V2 can be used to supply power to the load for a short time to prevent accidents. The control electrode of the thyristor D shown in FIG. 7 can also be modified to be connected to the load end P3 through the resistor R (note: but it is not recommended to use it in this way, because it affects the isolation performance of the control device C to the load). The resistor R shown in FIGS. 7 and 8 cannot use a capacitor, because during the disconnection process of the connecting device, if the dry line V2 is in a low voltage state, the capacitor will be quickly charged. When the dry line V2 is switched to a high voltage state, the thyristor D cannot be driven to extinguish the arc. In addition, the use of a capacitor will also cause the problem of being unable to extinguish the arc when the break of the connecting device is dithered. When the unidirectional device D uses a thyristor, the working mode of the unidirectional device can be realized by the potential difference between the dry line V2 and the dry line V1 to bias the unidirectional device in the forward direction (or close to the equipotential) to obtain a larger arc extinguishing current, which is suitable for large current arc extinguishing scenarios.

[0027] Figure 10 is a cost-effective embodiment of the control device of the components of the direct current micro-grid of the present application: it comprises a circuit breaker BK (optional, controllable breaking, manual closing), a control circuit M, a switch Q1 (fully controllable switch, fully controllable device, semiconductor device, for outputting square wave signal), a detection unit A (four-terminal circuit) composed of a power supply V+ for the trunk line V1, the trunk line V2, the control circuit M (the control circuit M can also use an independent power supply scheme according to the actual working condition) through the circuit breaker BK, the control circuit M is connected with the circuit breaker BK, the switch Q1 and the detection unit A, the switch Q1 is connected in series with the detection unit A and the trunk line V2, the detection unit A is used to detect the current of the trunk line V2, and the detection unit A is used to detect the potential difference of the trunk line V2 relative to the trunk line V1 (i.e. the power supply V+) (through the switch Q1), the detection unit A comprises an optical coupler OPT1, voltage detection devices Z1 (a plurality of diodes connected in series), Z2, a silicon controlled rectifier SCR1 and resistors (R1, R2, optional), the output end of the optical coupler OPT1 is connected with the control circuit M, the input end of the optical coupler OPT1 is connected in parallel with the voltage detection device Z1 through the resistor R1 to form a current detection circuit for detecting current (note: if quantitative measurement of current is required, other current sensors such as Hall current sensors can be used), the circuit has a current detection capability of milliamperes, and the voltage detection device has a small dynamic internal resistance, negative resistance and the ability to withstand large current impact, and also has the advantages of high cost performance, small size and low loss; the voltage detection switch (two-terminal voltage detection circuit, trigger switch, semi-controlled switch, note: when the unidirectional device D adopts a semi-controlled device, the voltage detection switch can be omitted) is connected by the voltage detection device Z2, R2 and the silicon controlled rectifier SCR1, so as to realize that the on-state voltage drop of the detection unit A is less than the conduction voltage threshold (when the unidirectional device D adopts a diode, the reverse bias voltage value is determined by the conduction voltage threshold of the detection unit A), which is conducive to improving the output current, and also has the advantages of high cost performance, small loss and strong overcurrent capacity; the silicon controlled rectifier SCR1 in series connection of the current detection circuit and the voltage detection switch can effectively improve the stability of current detection, and the detection unit A can also be completed by using other forms of circuit (such as connecting the control electrode of the silicon controlled rectifier D with the node in the Z1 circuit through Z2 and resistor R2; or connecting the control electrode of the silicon controlled rectifier D with the node in the Z1 circuit through resistor R2, etc., and the control circuit M is directly connected with the trunk line V2), note: the voltage detection device (ZA, Z1, Z2) defined in the present application is a semiconductor device that becomes conductive when the voltage across its two terminals reaches a certain voltage, and the voltage drop can be restored to a high resistance state, and the voltage detection device can be composed of a plurality of ordinary diodes connected in series, or a transient diode, or a zener diode, or a pressure sensitive resistor, etc.

[0028] Working principle: the circuit breaker BK is closed to provide power, the control circuit M provides the on control signal of the switch Q1, when the potential difference between the trunk V2 and the trunk V1 (V+) reaches the on voltage threshold of the detection unit A, the detection unit A is triggered (or driven) to be on, the control circuit M obtains the relevant information through the optocoupler OPT1, then controls (delays control) the switch Q1 to be off, and then detects the voltage of the node N2 (the voltage of V2 is detected through the internal loop of the detection unit A) to detect whether the switch Q1 is completely off and whether the unidirectional device D is damaged, if normal, the on control signal of the switch Q1 is provided again to perform the next working cycle, when an abnormality (such as arc extinction abnormality, overcurrent, leakage, etc.) occurs in the running, the circuit breaker BK is opened, note: the overvoltage suppression device RV (optional) connected with the switch Q1 is used for overvoltage protection, and the resistor R3 (optional) is used for overcurrent protection sampling.

[0029] In the scene where power loss is not allowed, such as an airplane, a car, etc., the circuit breaker BK is omitted, and the control circuit M provides the relevant information. The trunk V1 and the trunk V2 are grounded G (that is, the power supply ground, which can also be defined as the third trunk V3).

[0030] In the above embodiment, the control device C provides a direct current voltage to the trunk V2 first, and then cuts off the current after detecting the current to realize arc extinction, which has the functions of detection and arc extinction. For the working condition with high cost requirement, a pulse generator (which can be realized by using a two-terminal circuit) can be used as a pulse power source, which is equivalent to that the control device controls the high and low voltage signal output to the trunk V2. The defined arc extinction in the application means to prevent the generation of electric arc or to extinguish the electric arc that has been generated. The defined first breakpoint (second breakpoint) in the application is not limited to a specific single contact point (breakpoint), but can be a plurality of contact points (breakpoints, that is, a group of breakpoints) in series or parallel.

[0031] The components of the direct current micro-grid in the application include the switch of the unidirectional device D (or also include the components connected therewith) or the socket, which is extremely convenient to connect with the network of the direct current micro-grid.

[0032] When the connection device (SC1, SC2) is a socket (connector) in the direct current micro-grid and its components in the application, the live (hot) plug can be supported, and the distribution requirement of the direct current building 48V can be omitted, so that the cost and loss of the direct current system are reduced.

[0033] The connection device (S1, S2, S3, S4) of the direct current distribution network is a switch, which can be a manual switch (such as a flap switch, a knob switch, a button, a boat-shaped switch, a lamp switch, etc.), a travel switch, a circuit breaker, a relay or other mechanical switch, and the number of each different type of connection device S1, S2, S3 and S4 can be two or more.

[0034] The scheme of Fig. 4 is also suitable for other non-breaker type switches (connection devices), when two connection devices (front switch, rear socket, or both are switches) are used in series (suitable for the case where the unidirectional device D and the electrode P2 form a two-terminal selection switch, but not limited), the front connection device can also include a third break point, and the unidirectional device connected by the rear connection device is connected to the main line V2 through the third break point of the front connection device; when the rear connection device and the unidirectional device connected by the rear connection device form a three-terminal selection switch (Figs. 7 and 8), the front connection device does not need a third break point, and the selection switch formed by the front connection device and the unidirectional device connected by the front connection device can be a two-terminal selection switch or a three-terminal selection switch.

[0035] The connection devices of the present application can be connected in parallel (i.e. the electrodes P1 of each connection device have a common node), or in series (i.e. the main circuits of multiple connection devices are connected in series), or in a mixed connection, which has the advantages of flexibility and convenience; in special working conditions, a fuse can be connected in series with each unidirectional device (i.e. the electrode P2 of each connection device).

[0036] When the connection device of the present application is a linkage structure, a mechanical linkage structure or an electrical linkage structure can be used.

[0037] The present application defines that the unidirectional device D is connected to the main line V2 in common anode or common cathode; it includes the meaning of "the unidirectional device D is directly connected to the main line V2 in common anode (or common cathode)"; it also includes the meaning of "the unidirectional device D is connected to the main line V2 in common anode (or common cathode) through other components (or elements, or devices)", such as placing the unidirectional device D connected by the connection device S4 between the load end P3 and the break point K2, i.e. the unidirectional device D is connected to the main line V2 in common anode (or common cathode) through the electrode P2, i.e. in the on state of the connection device, the electrode P2 (through the unidirectional device D) is in electrical connection with the electrode P1 and the load end P3.

[0038] The unidirectional device D of the DC microgrid of the present application is preferably a non-controlled device (diode) or a semi-controlled device (thyristor, not limited to traditional thyristor, but can also use voltage-controlled semi-controlled device), which has the advantages of high voltage resistance, good overcurrent capability, and high cost performance. The unidirectional device D and the electrode P2 of the connection device form a two-terminal or three-terminal selection switch, which has the advantage of simple circuit.

[0039] The connecting device of the application, when cooperating with magnetic blowout arc (such as the connecting device of circuit breaker and the like which needs very high limit breaking fault current), the magnetic blow force is too strong to seriously reduce the electrical life of the contact when breaking the current, preferably the magnetic blow force of the breaking point K1 is greater than that of the breaking point K2, because of the intervention of the control device C, there is no arc breaking at the breaking point K1, or the arc is smaller than that of the breaking point K2, which is beneficial to improve the electrical life of the connecting device; when the current exceeds the arc extinguishing current of the control device C, the stronger limit arc breaking capacity of K1 can be used to break larger fault current.

[0040] The electrode P2 of the connecting device is connected with the one-way device D to form a selection switch, in the state of connecting device connection, the electrode P2 is electrically connected with the electrode P1 and the load end P3, which is beneficial to the real-time detection of the working state of the connecting device by the main line V2 (overcurrent detection, arc detection, arc extinguishing, etc. can detect the current of milliamperes level), in the state of disconnecting device connection, the electrode P2 is disconnected with the electrode P1 and the load end P3, and the one-way device D connected with the electrode P2 is in open circuit state (main circuit open circuit state or control circuit open circuit state), which effectively prevents the influence of the misdirected one-way device on the load, has very high anti-interference ability, and meets the use in various complex working conditions.

[0041] The direct current micro grid and its components of the application can directly break at least 1.414 times (peak value of alternating voltage) of the rated voltage of the traditional alternating switch (nominal value of the switch) according to the wiring mode of the application, and can realize the electrical life (up to 10 times or more) which is much higher than that in the alternating working condition (the arc burning time of the traditional alternating switch can reach 10 milliseconds, and the arc burning time of the application can be controlled within 0.5 milliseconds), solve the problems of short electrical life and mechanical life and single product type of the current direct current switch, greatly accelerate the popularization and application of direct current power supply, and only need to simply add a one-way device to the existing switch (when applied to a direct current switch which has arc breaking capacity, the electrical life of the switch can be greatly improved), and only need to add an electrode P2 and a one-way device to the socket (or plug, or connector), so that the compliant products which can be connected to the direct current micro grid of the application can be produced, the control device and the connecting device of the direct current micro grid can be independently standardized by different manufacturers, which is beneficial to the cultivation of industrial ecology and the acceleration of the development of direct current application.

[0042] The novel DC micro-grid of the application can standardize the parameters such as the pulse width of the main line V2 arc extinguishing current, the pulse width of stopping the power supply of the main line V2 to the main line V2 (both preferably recommended values are between 0.05 milliseconds to 1 millisecond, and appropriate specific values are determined according to system current and voltage), and the potential difference relative to the main line V1 (such as when a unidirectional device is used, a non-controlled device is used), thereby standardizing the electrical life related test technology standards of the connection device and the production technology standards of the control device, and being conducive to standardizing market management.

[0043] The novel DC micro-grid of the application can realize detection and arc extinguishing of the connection device of various current levels and unlimited number of dispersed layouts for a long distance by a single node (the main line V2), which is conducive to the miniaturization, light weight and intelligentization of the system, greatly improves the economy, has high safety, and is extremely suitable for complex application scenarios such as buildings (families, industries, businesses, etc.), ships, automobiles, aircraft (airplanes, etc.), locomotives, various equipment, etc.

[0044] The application has the advantages of wide application range and high safety.

Claims

1. A DC microgrid, comprising a first trunk line for power supply, characterized in that: It also includes a second trunk line, which is used for arc extinguishing.

2. The DC microgrid according to claim 1, characterized in that: When current appears in the second trunk line, the current is cut off, and then the voltage of the second trunk line is supplied again.

3. The DC microgrid according to claim 1, characterized in that: For building power grids, ship power grids, locomotive power grids, aircraft power grids, automobile power grids, or equipment power grids.

4. The DC microgrid according to claim 1, characterized in that: It also includes a connecting device, with the first trunk line and the second trunk line connected to the connecting device. The first trunk line is powered through the connecting device, and the second trunk line extinguishes the arc of the connecting device. The number of connecting devices is two or more. It also includes a unidirectional device. The connecting device includes at least a first electrode and a second electrode. A first break and a second break are formed between the first electrode, the second electrode, and the load terminal. The first electrode is connected to the first trunk line, and the second electrode is connected to the unidirectional device to form a selection switch. Each unidirectional device is either common anode or common cathode and connected to the second trunk line. When the connecting device is on, the second electrode is electrically connected to the first electrode and the load terminal. When the connecting device is off, the second electrode is disconnected from the first electrode and the load terminal.

5. The DC microgrid according to claim 1, characterized in that: It also includes a control device connected to the second trunk line, the control device being used to provide energy to the second trunk line.

6. The DC microgrid according to claim 5, characterized in that: The control device is used to detect the second main line current.

7. The DC microgrid according to claim 5, characterized in that: The control device is used to detect the voltage of the second trunk line.

8. The DC microgrid according to claim 5, characterized in that: The control device is connected to the first trunk line and is used to provide energy to the first trunk line.

9. The DC microgrid according to claim 5, characterized in that: When the first main line loses power and the second main line receives current, the control device maintains power supply to the second main line.

10. The DC microgrid according to claim 5, characterized in that: The control device is connected to the first main line and is used to detect fault arcs.

11. The DC microgrid according to claim 5, characterized in that: The control device is connected to the first trunk line and is used to detect leakage current.

12. The DC microgrid according to claim 5, characterized in that: It also includes a connecting device, to which the first trunk line and the second trunk line are connected. The first trunk line is powered through the connecting device, and the second trunk line extinguishes the arc of the connecting device.

13. The DC microgrid according to claim 12, characterized in that: The number of connection devices is two or more, and it also includes unidirectional devices. Each connection device includes at least a first electrode and a second electrode. A first break and a second break are formed between the first electrode, the second electrode, and the load terminal. The first electrode is connected to the first trunk line, and the second electrode is connected to the unidirectional device to form a selection switch. Each unidirectional device is either common anode or common cathode and is connected to the second trunk line. When the connection device is on, the second electrode is electrically connected to the first electrode and the load terminal. When the connection device is off, the second electrode is disconnected from the first electrode and the load terminal.

14. The DC microgrid according to claim 13, characterized in that: The first electrode and the second electrode, or the load terminal, form the first breakpoint, and the second electrode and the load terminal form the second breakpoint.

15. The DC microgrid according to claim 13, characterized in that: The connecting device is a sliding connection, a bridging connection, or a linkage structure.

16. The DC microgrid according to claim 13, characterized in that: The unidirectional device is an uncontrolled device.

17. The DC microgrid according to claim 16, characterized in that: When the connection device is connected, the reverse bias voltage of the unidirectional device is greater than the maximum allowable operating voltage drop of the first trunk line.

18. The DC microgrid according to claim 17, characterized in that: The reverse bias voltage value during the period when the second trunk line carries current is less than or equal to the reverse bias voltage value during the period when the second trunk line has no current.

19. The DC microgrid according to claim 16, characterized in that: The control device is used to detect overcurrent in the connection device by detecting the second main line current.

20. The DC microgrid according to claim 13, characterized in that: The unidirectional device is a semi-controlled device, and all the semi-controlled devices are connected in a common anode. The control electrode of the semi-controlled device is connected to the anode of the semi-controlled device, and the cathode of the semi-controlled device is connected to the second electrode. The semi-controlled device is connected in series with at least one diode.

21. The DC microgrid according to claim 20, characterized in that: The control electrode of the semi-controlled device is connected to the anode of the semi-controlled device via a voltage detection device and the diode.

22. The DC microgrid according to claim 13, characterized in that: The unidirectional device is a semi-controlled device, and each semi-controlled device is connected in a common anode configuration. The control electrode of the semi-controlled device is connected to the first electrode, and the cathode of the semi-controlled device is connected to the second electrode.

23. The DC microgrid according to claim 13, characterized in that: The unidirectional device is a semi-controlled device, and each of the semi-controlled devices is connected in a common anode configuration. The control electrode of the semi-controlled device is connected to the second electrode, and the cathode of the semi-controlled device is connected to the load terminal.

24. The DC microgrid according to claim 13, characterized in that: The unidirectional device is a semi-controlled device, and each semi-controlled device is connected in a common anode configuration. The control electrode of the semi-controlled device is connected to the load terminal, and the cathode of the semi-controlled device is connected to the second electrode.

25. The DC microgrid according to any one of claims 20 to 24, characterized in that: A resistor is connected in series with the control electrode of the semi-controlled device.

26. The DC microgrid according to claim 13, characterized in that: The connecting device may be a switch, a socket, a plug, or a connector.

27. The DC microgrid according to claim 13, characterized in that: It also includes a display unit, wherein the series circuit formed by the unidirectional device and the first electrode is connected in parallel with the display unit.

28. The DC microgrid according to claim 13, characterized in that: The two connecting devices are connected in series. The connecting device of the front stage further includes a third break point. The unidirectional device connected to the connecting device of the rear stage is connected to the second trunk line through the third break point.

29. The DC microgrid according to claim 13, characterized in that: The two connecting devices are connected in series. The unidirectional device connected to the connecting device of the preceding stage and the second electrode of the connecting device of the preceding stage form a two-terminal or three-terminal selection switch. The connecting device of the following stage and the unidirectional device connected to the connecting device of the following stage form a three-terminal selection switch.

30. The DC microgrid according to claim 13, characterized in that: It also includes a power distribution unit, which includes the control device and a circuit breaker. The circuit breaker includes at least a first-pole switch and a second-pole switch. The first main line is connected to the connection device through the first-pole switch, and the second main line is connected through the second-pole switch and the unidirectional device.

31. A component based on the DC microgrid of claim 5, characterized in that: The component is the control device, which comprises a control circuit, a fully controllable switch, and a detection unit. The control circuit is connected to the fully controllable switch and the detection unit. The fully controllable switch, the detection unit, and the second main line are connected in series. The detection unit is used to detect the current of the second main line.

32. The component of the DC microgrid according to claim 31, characterized in that: The detection unit is a trigger switch used to detect the potential difference between the second trunk line and the first trunk line or the power supply.

33. The component of the DC microgrid according to claim 31, characterized in that: The detection unit includes a voltage detection device and an optocoupler. The input terminal of the optocoupler is connected in parallel with the voltage detection device, and the output terminal of the optocoupler is connected to the control circuit.

34. The component of the DC microgrid according to claim 31, characterized in that: It also includes a circuit breaker that can be manually closed and electrically disconnected, through which power is supplied to the first main line and the second main line, and the circuit breaker is connected to the control circuit.

35. A component based on the DC microgrid of claim 16, characterized in that: The component is the connection device, which includes the unidirectional device.

36. A component based on the DC microgrid of claim 25, characterized in that: The component is the connection device, which further includes the unidirectional device, the diode, and the resistor.

37. A component based on the DC microgrid of claim 25, characterized in that: The component is the connection device, which further includes the unidirectional device, the resistor, the voltage detection device, and the diode.

38. A component based on the DC microgrid of claim 25, characterized in that: The component is the connection device, which further includes the semi-controlled device and the resistor.

39. A component based on the DC microgrid of claim 4, characterized in that: The component is the connecting device, and the magnetic blowing force at the first break point of the connecting device is greater than the magnetic blowing force at the second break point.

40. A component based on the DC microgrid of claim 30, characterized in that: The component is the power distribution unit.

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