Switching device, inverter system and energy storage system

Abstract

The utility model provides a switching device, an inverter system and an energy storage system. The first electromagnetic switch and the second normally-closed auxiliary switch in the switching device and the grid-connected interface of the inverter form a first control loop, and the second electromagnetic switch and the first normally-closed auxiliary switch in the switching device and the off-grid interface of the inverter form a second control loop. The first electromagnetic switch is mechanically interlocked with the first normally-closed auxiliary switch, the first electromagnetic switch is mechanically interlocked with the second electromagnetic switch, the second electromagnetic switch is mechanically interlocked with the second normally-closed auxiliary switch, and the first control loop is used for controlling the first electromagnetic switch to be switched on and controlling the first normally-closed auxiliary switch to be switched on when the inverter is in grid connection; and the second control loop is used for controlling the second electromagnetic switch to be closed and controlling the second normally-closed auxiliary switch to be opened when the inverter is off-grid so as to open the first control loop. According to the switching device, the power supply can be switched for the load.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to a switching device, an inverter system and an energy storage system. Background Art

[0002] The inverter and the grid are often used as dual power sources to supply power to the load. In the event of a single fault or fault recovery in the dual power sources, the dual power sources need to be switched accordingly. In addition, during the switching process, the switch from the grid side to the load side and the switch from the inverter off-grid side to the load side need to be electrically and mechanically interlocked to ensure that the off-grid side voltage is not applied to the grid side, or vice versa.

[0003] Therefore, how to achieve effective switching of load power supply is a technical problem that needs to be solved. Utility Model Content

[0004] In view of this, the present application provides a switching device, an inverter system and an energy storage system, which can switch the power supply for the load to ensure uninterrupted power supply and power supply safety of the load.

[0005] In a first aspect, the present application provides a switching device. The switching device comprises: a first electromagnetic switch, a second electromagnetic switch, a first normally closed auxiliary switch, and a second normally closed auxiliary switch;

[0006] The first electromagnetic switch is used to connect the second normally closed auxiliary switch, the grid-connected interface of the inverter and the load, wherein the grid-connected interface is used to connect to the power grid; the second normally closed auxiliary switch is used to connect to the grid-connected interface, thereby forming a first control loop together with the grid-connected interface and the first electromagnetic switch;

[0007] The second electromagnetic switch is used to connect the first normally closed auxiliary switch, the off-grid interface of the inverter and the load; the first normally closed auxiliary switch is used to connect to the off-grid interface, thereby forming a second control loop together with the off-grid interface and the second electromagnetic switch;

[0008] Wherein, the first electromagnetic switch is mechanically interlocked with the first normally closed auxiliary switch, the first electromagnetic switch is mechanically interlocked with the second electromagnetic switch, and the second electromagnetic switch is mechanically interlocked with the second normally closed auxiliary switch;

[0009] The first control loop is used to control the first electromagnetic switch to close when the inverter is in grid-connected operation, so as to conduct the grid-connected interface and the load, and to control the first normally closed auxiliary switch to open, so as to disconnect the second control loop, so that the inverter and the grid supply power to the load through the grid-connected interface;

[0010] The second control loop is used to control the second electromagnetic switch to close when the inverter is running off-grid to connect the off-grid interface and the load, and to control the second normally closed auxiliary switch to open to disconnect the first control loop so that the inverter can supply power to the load through the off-grid interface.

[0011] In one embodiment, the first electromagnetic switch includes a first main contact and a first induction coil, wherein the first main contact is connected between the grid-connected interface and the load, the first induction coil is connected in series with the second normally closed auxiliary switch, and the first induction coil and the second normally closed auxiliary switch are also connected to the grid-connected interface, thereby forming a first control loop together with the grid-connected interface;

[0012] The second electromagnetic switch includes a second main contact and a second induction coil, wherein the second main contact is connected between the off-grid interface and the load, the second induction coil is connected in series with the first normally closed auxiliary switch, and the second induction coil and the first normally closed auxiliary switch are also connected to the off-grid interface, thereby forming a second control loop together with the off-grid interface.

[0013] In one embodiment, the first main contact is mechanically interlocked with the first normally closed auxiliary switch, the first main contact is mechanically interlocked with the second main contact, and the second main contact is mechanically interlocked with the second normally closed auxiliary switch;

[0014] The first control circuit is used to energize when the inverter is connected to the grid, so that the first induction coil generates a first electromagnetic signal, and the first electromagnetic signal is used to control the first main contact to close, so as to conduct the grid-connected interface and the load; when the first main contact is closed, the first normally closed auxiliary switch is opened to disconnect the second control circuit;

[0015] The second control circuit is used to energize when the inverter is running off-grid, so that the second induction coil generates a second electromagnetic signal, and the second electromagnetic signal is used to control the closing of the second main contact to conduct the off-grid interface and the load; when the second main contact is closed, the second normally closed auxiliary switch is opened to disconnect the first control circuit.

[0016] In one embodiment, the first induction coil is connected to one of the phase line and the neutral line of the grid-connected interface, and the second normally closed auxiliary switch is connected to the other of the phase line and the neutral line of the grid-connected interface;

[0017] The first main contact includes a first phase line main contact and a first neutral line main contact, wherein the first phase line main contact is connected to the phase line of the grid-connected interface in a one-to-one correspondence, and the first neutral line main contact is connected to the neutral line of the grid-connected interface in a corresponding manner.

[0018] In one embodiment, the second induction coil is connected to one of the phase line and the neutral line of the off-grid interface, and the first normally closed auxiliary switch is connected to the other of the phase line and the neutral line of the off-grid interface;

[0019] The second main contact includes a second phase line main contact and a second neutral line main contact, wherein the second phase line main contact is connected to the phase line of the off-grid interface in a one-to-one correspondence, and the second neutral line main contact is connected to the neutral line of the off-grid interface in a corresponding manner.

[0020] In one embodiment, the switching device further includes a mechanical interlocking accessory, which is disposed between the first electromagnetic switch and the second electromagnetic switch, and mechanically connects the first electromagnetic switch and the second electromagnetic switch into one, and mechanically interlocks the first electromagnetic switch and the second electromagnetic switch.

[0021] In one embodiment, the first normally closed auxiliary switch is installed on the first electromagnetic switch, and the second normally closed auxiliary switch is installed on the second electromagnetic switch.

[0022] In one embodiment, the first electromagnetic switch and the second electromagnetic switch use AC contactors, and the first normally closed auxiliary switch and the second normally closed auxiliary switch use normally closed auxiliary contacts;

[0023] Among them, the rated voltages of the first electromagnetic switch, the second electromagnetic switch, the first normally closed auxiliary switch and the second normally closed auxiliary switch are all within the grid voltage range.

[0024] The second aspect of the present application provides an inverter system. The inverter system includes an inverter and a switching device as described in the first aspect or any one of the embodiments of the first aspect, the inverter is connected to the switching device, the switching device is also used to connect to a load, and the inverter is used to output AC power to the load through the switching device.

[0025] The third aspect of the present application provides an energy storage system. The energy storage system includes a battery pack, an inverter, and a switching device as described in the first aspect or any one of the embodiments of the first aspect, wherein the battery pack and the switching device are both connected to the inverter, and the switching device is also used to connect to a load, and the inverter is used to convert the direct current provided by the battery pack into alternating current, and output the alternating current to the load through the switching device.

[0026] Compared with the prior art, this application has the following advantages:

[0027] 1. The switching device of the present application can be applied to the power supply scenario of the load and used in conjunction with the inverter. It can realize the function of switching the load to be powered by the power grid and / or the inverter, and also realize the function of switching the inverter to the grid-connected interface or the off-grid interface to carry the load. The switching efficiency is high and the safety is high, which is conducive to ensuring the uninterrupted power supply of the load and the safe operation of the inverter.

[0028] 2. The switching device of the present application arranges the first electromagnetic switch and the second normally closed auxiliary switch in the same control circuit, and the second electromagnetic switch and the first normally closed auxiliary switch in another control circuit, so that the on-off state of the first electromagnetic switch can depend on the power-on condition of the first control circuit, and the on-off state of the second electromagnetic switch can depend on the power-on condition of the second control circuit. In addition, the first electromagnetic switch and the first normally closed auxiliary switch are mechanically interlocked, the second electromagnetic switch and the second normally closed auxiliary switch are mechanically interlocked, and the first electromagnetic switch and the second electromagnetic switch are mechanically interlocked. Therefore, when the first control circuit is powered on, the first electromagnetic switch can conduct the grid-connected interface and the load, and the second normally closed auxiliary switch can conduct the grid-connected interface and the load. The switch can synchronously disconnect the second control loop, so that the second electromagnetic switch cannot conduct the off-grid interface and the load; when the second control loop is energized, the second electromagnetic switch can conduct the off-grid interface and the load, and the first normally closed auxiliary switch can synchronously disconnect the first control loop, so that the first electromagnetic switch cannot conduct the grid-connected interface and the load. In this way, the grid-connected interface and the off-grid interface of the inverter can select one to supply power to the load, thereby automatically switching the power supply for the load without the need for remote control of the host computer or the need for an additional controller. Therefore, the switching efficiency of the switching device of the present application is high and the cost is low. In addition, the interlocking design also ensures the effective switching and safety of use of the switching device.

[0029] 3. The switching device of the present application can be composed of contactors, auxiliary contact devices, and mechanical accessories. The contactors and auxiliary contact devices can be attracted and separated very quickly, so the switching time of the switching device can be very short (such as within 100ms). In addition, it is easy to integrate into one and is cheap. Therefore, the switching device of the embodiment of the present application has the advantages of high switching efficiency, simple structure, small space occupation, low cost, and easy implementation.

[0030] 4. The switching device of the present application can realize mechanical interlocking and electrical interlocking between the switch from the grid side to the load side (i.e., the first electromagnetic switch) and the switch from the off-grid side to the load side (i.e., the second electromagnetic switch), and in the case of a single fault, the off-grid side voltage will not be applied to the grid side (i.e., the AC voltage output by the inverter off-grid interface will not be transmitted to the inverter grid-connected interface), or the grid side voltage will not be applied to the off-grid side (i.e., the AC voltage output by the inverter grid-connected interface will not be transmitted to the off-grid interface). In this way, when the inverter is off-grid, the safety of the grid-side inspection and maintenance can be guaranteed to avoid the occurrence of safety accidents. In addition, overstress of the electronic components of the inverter can also be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 It is a schematic diagram of an application scenario of the switching device provided in an embodiment of the present application.

[0033] Figure 2 yes Figure 1 A structural schematic diagram of a switching device in FIG.

[0034] Figure 3 yes Figure 1 A connection diagram of a switching device in FIG.

[0035] Figure 4 It is a schematic diagram of an inverter system provided in an embodiment of the present application.

[0036] Figure 5 It is a schematic diagram of an energy storage system provided in an embodiment of the present application.

[0037] Main component symbols

[0038] Switching device 100

[0039] First electromagnetic switch 10

[0040] Second electromagnetic switch 20

[0041] First normally closed auxiliary switch 30

[0042] Second normally closed auxiliary switch 40

[0043] Mechanical interlocking accessories 50

[0044] Inverter 200

[0045] Battery interface 201

[0046] Photovoltaic interface 202

[0047] Grid connection interface 203

[0048] Off-grid interface 204

[0049] Battery Pack 300

[0050] Photovoltaic module 400

[0051] Load 500

[0052] Grid 600

[0053] Inverter System 1000

[0054] Energy Storage System 2000 DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only embodiments of a part of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should belong to the scope of protection of the present application. In the absence of conflict, the following different embodiments and features in the embodiments can be combined with each other. It should be noted that for ordinary technicians in the field, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. The term "including" and any of their variations are intended to cover non-exclusive inclusions.

[0056] See also Figure 1 , which is a schematic diagram of an application scenario of the switching device provided in an embodiment of the present application. Figure 1 The scenario in the diagram includes a switching device 100 , an inverter 200 , a battery pack 300 , a photovoltaic assembly 400 , a load 500 and a grid 600 .

[0057] The inverter 200 may include an inverter circuit (not shown), a DC-DC conversion circuit (not shown), a battery interface 201 , a photovoltaic interface 202 , a grid-connected interface 203 and an off-grid interface 204 .

[0058] The inverter circuit can be used to invert direct current into alternating current. In some cases, the inverter circuit can be compatible with the inversion and rectification functions. That is, the inverter circuit can also be used to rectify alternating current into direct current. It is understandable that the topology of the inverter circuit can be determined according to actual conditions, for example, it can be a full-bridge topology, a half-bridge topology, etc.

[0059] The battery interface 201 is used to connect to the positive and negative poles of the battery pack 300. The photovoltaic interface 202 is used to connect to the output interface of the photovoltaic assembly 400. The grid-connected interface 203 is used to connect to the power grid 600, wherein the phase line L' of the grid-connected interface 203 corresponds to the phase line L connected to the power grid 600, and the neutral line N' of the grid-connected interface 203 corresponds to the neutral line N connected to the power grid 600. The grid-connected interface 203 is also used to connect to the switching device 100 through the phase line L' and the neutral line N'. Similarly, the off-grid interface 204 is also used to connect to the switching device 100 through its phase line L" and neutral line N". The switching device 100 is also connected to the phase line L"' and neutral line N"' of the load 500.

[0060] The inverter circuit is electrically connected to the grid-connected interface 203 and the off-grid interface 204, and is also electrically connected to the battery interface 201 and the photovoltaic interface 202 through the DC-DC conversion circuit. The inverter 200 can access the DC power provided by the battery pack 300 through the battery interface 201, and can also access the DC power provided by the photovoltaic module 400 through the photovoltaic interface 202. The inverter 200 can output AC power through the grid-connected interface 203 or the off-grid interface 204. In some cases, when the inverter 200 is compatible with the rectification function, the inverter 200 can also access AC power through the grid-connected interface 203 and output DC power through the battery interface 201.

[0061] The inverter 200 may also be provided with a corresponding switch (not shown) to control the electrical connection between the grid-connected interface 203 and the power grid 600. The inverter 200 may also be provided with a corresponding switch (not shown) to control whether the inverter circuit transmits AC power through the grid-connected interface 203 or through the off-grid interface 204, that is, when the inverter 200 transmits AC power through the grid-connected interface 203, the inverter 200 is in a grid-connected state at this time, and when the inverter 200 transmits AC power through the off-grid interface 204, the inverter 200 is in an off-grid state at this time.

[0062] Understandably, the battery pack 300 can adopt a battery cell module (not shown in the figure). Of course, the battery pack 300 can also include a battery cell module and a battery management system BMS (Battery Management System, not shown in the figure) for managing the state parameters of the battery cell module. In some cases, the battery pack 300 is also connected to a direct current-direct current (DC-DC) conversion circuit (not shown in the figure), so that the battery cell module can adjust the DC voltage or DC power through the DC-DC conversion circuit, so that the input DC voltage / DC power meets the requirements of the battery pack 300, or the output DC voltage / DC power meets the requirements of the inverter 200. The photovoltaic assembly 400 can be composed of several photovoltaic panels, so it can be used to convert solar energy into electrical energy. In some cases, the DC-DC conversion circuit is also connected to a maximum power point tracking (Maximum power point tracking, MPPT) circuit, so that the photovoltaic system charges the battery pack 300 with maximum power output. Of course, in other cases, the DC-DC conversion circuit and the MPPT circuit can also be integrated in the inverter 200.

[0063] The load 500 may be a single-phase, two-phase or three-phase load, and no limitation is made here. That is, the phase line L'' of the load 500 may be a single-phase line (i.e., any one of the three-phase lines A, B, and C), a two-phase line (i.e., any two of the three-phase lines A, B, and C), or a three-phase line (i.e., the three-phase lines A, B, and C).

[0064] Correspondingly, the AC power provided by the inverter 200 and the grid 600 to the load 500 may also be single-phase, two-phase or three-phase AC power, which may be determined specifically according to the load 500. Among them, the phase line L' of the grid-connected interface 203 of the inverter 200, the phase line L" of the off-grid interface 204, the phase line L of the grid 600 and the phase line L"' of the load 500 are consistent in number and phase sequence.

[0065] In a specific implementation, the switching device 100 can be integrated separately. Of course, in practice, the switching device 100 can also adopt other integration methods or other implementation methods, which does not constitute a limitation on the present application. In actual application, the switching device 100 can first establish a connection with the grid-connected interface 203, the off-grid interface 204, the power grid 600 and the load 500, and then can be used in conjunction with the inverter 200 to switch the corresponding power supply for the load 500 when the inverter 200 is grid-connected or off-grid. Among them, the control logic of the inverter 200 on-grid and off-grid operation can be pre-set or manually selected, depending on the specific situation, which does not constitute a limitation on the present application.

[0066] For example, when the photovoltaic assembly 400 generates electricity and the power grid 600 operates normally, the grid-connected interface 203 is electrically connected to the power grid 600, and the inverter 200 is in a grid-connected operation state. Correspondingly, the switching device 100 at this time electrically connects the grid-connected interface 203 of the inverter 200 to the load 500. At the same time, the off-grid interface 204 of the inverter 200 is electrically disconnected from the load 500 (which can be simply described as the inverter 200 is in a grid-connected and loaded state). When the inverter 200 is in grid-connected operation, based on the preset control logic of the inverter 200, the electric energy generated by the photovoltaic assembly 400 can power the load 500, and can also charge the battery pack 300, and can also feed power to the power grid 600; the load 500 can be powered by a combination of the power grid 600 and the inverter 200.

[0067] As another example, when the power grid 600 fails or loses power, the switching device 100 controls the grid-connected interface 203 of the inverter 200 to disconnect the load 500, and at the same time, the off-grid interface 204 of the inverter 200 is electrically connected to the load 500 (which can be simply described as the inverter 200 is in an off-grid loaded state), so that the load 500 can be powered uninterruptedly and work continuously. When the power grid 600 is restored after power failure, the inverter 200 can refer to the preset control logic when the photovoltaic module 400 generates electricity and the power grid 600 operates normally, and the switching device 100 can refer to the switching process when the inverter 200 is connected to the grid, which will not be repeated here.

[0068] Understandably, Figure 1 The illustrated scenario does not constitute a specific limitation on the application scenario of the switching device 100 of the embodiment of the present application. In other embodiments, the scenario may also include more or fewer devices, equipment, modules, circuits or components than those shown in the figure. For example, in one embodiment, the inverter 200 may omit any one of the battery interface 201 and the photovoltaic interface 202.

[0069] Next, the switching device 100 according to the embodiment of the present application is further introduced.

[0070] Please also read Figure 2 The switching device 100 includes a first electromagnetic switch 10 , a second electromagnetic switch 20 , a first normally closed auxiliary switch 30 , a second normally closed auxiliary switch 40 and a mechanical interlocking accessory 50 .

[0071] like Figure 2 As shown, the first normally closed auxiliary switch 30 can be installed on the first electromagnetic switch 10 to be assembled with the first electromagnetic switch 10. The second normally closed auxiliary switch 40 can be installed on the second electromagnetic switch 20 to be assembled with the second electromagnetic switch 20. The mechanical interlocking accessory 50 can be provided between the first electromagnetic switch 10 and the second electromagnetic switch 20, or provided on the same side of the first electromagnetic switch 10 and the second electromagnetic switch 20, so as to connect the first electromagnetic switch 10 and the second electromagnetic switch 20, so that the entire switching device 100 is assembled as a whole. In this way, in actual application, it can be conveniently implemented and the occupied space can be reduced, and the wiring can also be more economical.

[0072] In an embodiment of the present application, the first electromagnetic switch 10 is connected to the second normally closed auxiliary switch 40, the grid-connected interface 203 of the inverter 200 and the load 500, and the second normally closed auxiliary switch 40 is also connected to the grid-connected interface 203, so that the first electromagnetic switch 10, the second normally closed auxiliary switch 40 and the grid-connected interface 203 together constitute a first control loop.

[0073] The second electromagnetic switch 20 is connected to the first normally closed auxiliary switch 30, the off-grid interface 204 of the inverter 200 and the load 500. The first normally closed auxiliary switch 30 is also connected to the off-grid interface 204, so that the second electromagnetic switch 20, the first normally closed auxiliary switch 30 and the off-grid interface 204 together constitute a second control loop.

[0074] Specifically, please see Figure 3 The first electromagnetic switch 10 includes first main contacts TL1, TN1 and a first induction coil A1. For the convenience of distinction, TL1 can also be called the first phase line main contact, and TN1 can be called the first neutral line main contact.

[0075] The first main contacts TL1 and TN1 are connected between the grid-connected interface 203 and the load 500. Figure 3 The first end of the first main contact TN1 is connected to the phase line L' of the grid-connected interface 203 in a one-to-one correspondence, and the first end of the first main contact TN1 is connected to the neutral line N' of the grid-connected interface 203 in a corresponding manner. The second end of the first main contact TL1 (for convenience of description, Figure 3 The second end (denoted by 2 in the figure) is connected to the phase line L'' of the load 500 in a one-to-one correspondence, and the second end of the first main contact TN1 is connected to the neutral line N'' of the load 500 in a corresponding manner.

[0076] It should be understood that since the phase line L' of the grid-connected interface 203 is also connected to the phase line L of the grid 600, and the neutral line N' of the grid-connected interface 203 is also connected to the neutral line N of the grid 600, the first end of the first main contact TL1 will also be connected one-to-one with the phase line L of the grid 600, and the first end of the first main contact TN1 will also be connected correspondingly with the neutral line N of the grid 600.

[0077] The first induction coil A1 and the second normally closed auxiliary switch 40 (corresponding to Figure 3 K2 in the figure is connected in series, and the first induction coil A1 and the second normally closed auxiliary switch 40 are also connected to the grid-connected interface 203, thereby forming a first control loop together with the grid-connected interface 203. Further, the first end of the first induction coil A1 is connected to the phase line L' of the grid-connected interface 203, the second end of the first induction coil A1 is connected to the second end of the second normally closed auxiliary switch 40, and the first end of the second normally closed auxiliary switch 40 is connected to the neutral line N' of the grid-connected interface 203. Alternatively, the first end of the first induction coil A1 is connected to the neutral line N' of the grid-connected interface 203, the second end of the first induction coil A1 is connected to the second end of the second normally closed auxiliary switch 40, and the first end of the second normally closed auxiliary switch 40 is connected to the phase line L' of the grid-connected interface 203. The first induction coil A1, the second normally closed auxiliary switch 40, and the grid-connected interface 203 are thus connected to form a first control loop.

[0078] Please continue reading Figure 3 The second electromagnetic switch 20 includes second main contacts TL2, TN2 and a second induction coil A2. For the convenience of distinction, TL2 can also be called a second phase line main contact, and TN2 can be called a second neutral line main contact.

[0079] The second main contacts TL2 and TN2 are connected between the off-grid interface 204 and the load 500. Further, the first end of the second main contact TL" is connected to the phase line L" of the off-grid interface 204 in a one-to-one correspondence, and the first end of the second main contact TN" is connected to the neutral line N" of the off-grid interface 204 in a corresponding manner. The second end of the second main contact TL" is connected to the phase line L"' of the load 500 in a one-to-one correspondence, and the second end of the second main contact TN" is connected to the neutral line N"' of the load 500 in a one-to-one correspondence.

[0080] The second induction coil A2 is connected to the first normally closed auxiliary switch 30 (corresponding to Figure 3 K1) in series, and the second induction coil A2 and the first normally closed auxiliary switch 30 are also connected to the off-grid interface 204, thereby forming a second control loop together with the off-grid interface 204. Further, the first end of the second induction coil A2 is connected to the phase line L'' of the off-grid interface 204, the second end of the second induction coil A2 is connected to the second end of the first normally closed auxiliary switch 30, and the first end of the first normally closed auxiliary switch 30 is connected to the neutral line N'' of the off-grid interface 204. Alternatively, the first end of the second induction coil A2 is connected to the neutral line N'' of the off-grid interface 204, the second end of the second induction coil A2 is connected to the second end of the first normally closed auxiliary switch 30, and the first end of the first normally closed auxiliary switch 30 is connected to the phase line L'' of the off-grid interface 204. The second induction coil A2, the first normally closed auxiliary switch 30, and the off-grid interface 204 are thus connected to form a second control loop.

[0081] In the embodiment of the present application, the first electromagnetic switch 10 and the second electromagnetic switch 20 are normally open switches, and the first normally closed auxiliary switch 30 and the second normally closed auxiliary switch 40 are both normally closed switches. Among them, the types of the first electromagnetic switch 10, the second electromagnetic switch 20, the first normally closed auxiliary switch 30 and the second normally closed auxiliary switch 40 are not limited, as long as they can achieve the corresponding functions. For example, in the present embodiment, the first electromagnetic switch 10 and the second electromagnetic switch 20 can use AC contactors, wherein the first main contact of the first electromagnetic switch 10 and the second main contact of the second electromagnetic switch 20 are normally open contacts. The first normally closed auxiliary switch 30 and the second normally closed auxiliary switch 40 can use normally closed auxiliary contacts.

[0082] In the embodiment of the present application, since the switching device 100 is used in conjunction with the inverter 200 that can be connected to or off the grid and run with load, the rated voltages of the first electromagnetic switch 10, the second electromagnetic switch 20, the first normally closed auxiliary switch 30, and the second normally closed auxiliary switch 40 are all within the voltage range of the power grid 600. For example, when the power grid 600 is a 220V municipal power grid, the rated voltages of the first electromagnetic switch 10, the second electromagnetic switch 20, the first normally closed auxiliary switch 30, and the second normally closed auxiliary switch 40 can be within the range of 210 to 230V. Such a design can prevent the first electromagnetic switch 10, the second electromagnetic switch 20, the first normally closed auxiliary switch 30, and the second normally closed auxiliary switch 40 from being damaged and failing due to overstress, thereby avoiding affecting the normal operation of the inverter 200, the power grid 600, and the load 500.

[0083] In the embodiment of the present application, the first electromagnetic switch 10 and the first normally closed auxiliary switch 30 are mechanically interlocked, the second electromagnetic switch 20 and the second normally closed auxiliary switch 40 are mechanically interlocked, and the first electromagnetic switch 10 and the second electromagnetic switch 20 are mechanically interlocked.

[0084] Specifically, if Figure 3 As shown, the first main contacts TL1 and TN1 in the first electromagnetic switch 10 are mechanically interlocked with the first normally closed auxiliary switch 30. Therefore, the first main contacts TL1 and TN1 and the first normally closed auxiliary switch 30 will not be closed at the same time. Therefore, when the first main contacts TL1 and TN1 are switched from an open state to a closed state, the first normally closed auxiliary switch 30 is switched from a closed state to an open state. In this way, a short circuit of the grid-connected interface 203 of the inverter 200 can be avoided.

[0085] Similarly, the second main contacts TL2 and TN2 in the second electromagnetic switch 20 are mechanically interlocked with the second normally closed auxiliary switch 40. Therefore, the second main contacts TL2 and TN2 and the second normally closed auxiliary switch 40 will not be closed at the same time. Therefore, when the second main contacts TL2 and TN2 are switched from an open state to a closed state, the second normally closed auxiliary switch 40 is switched from a closed state to an open state. In this way, a short circuit of the off-grid interface 204 of the inverter 200 can be avoided.

[0086] The first main contact TL1 and the second main contact TL2 are mechanically interlocked.

[0087] It is understood that the embodiment of the present application does not limit the implementation method of mechanical interlocking. Take the first main contact TL1 and the second main contact TL2 as an example. For example, a mechanical connection can be established between the first main contact TL1 and the second main contact TL2 through the mechanical interlocking accessory 50, so that the first main contact TL1 and the second main contact TL2 can achieve mechanical interlocking through the mechanical interlocking accessory 50.

[0088] The structure of the mechanical interlocking accessory 50 is not limited, as long as the mechanical structure can be used to achieve the function that the first main contact and the second main contact cannot be turned on at the same time. For example, the mechanical interlocking accessory 50 can use a mechanical connecting rod. When one of the first main contact and the second main contact is turned on, the other of the first main contact and the second main contact will be stuck and cannot be closed, thereby ensuring that the first main contact and the second main contact are in a closed state. Therefore, even if the electrical interlocking fails, it can be ensured that the first main contact and the second main contact will not be closed at the same time, which can further ensure the effective switching of the switching device 100 and ensure the normal and safe operation of the switching device 100 and the circuit connected to the switching device 100.

[0089] Based on the above design, when the inverter 200 is connected to the grid, the grid 600 supplies power normally, and the inverter 200 outputs the AC current required by the load 500 through the grid interface 203. Of course, in some cases, the grid 600 can also output AC current together with the inverter 200 to meet the load requirements. In general, at this time, the inverter 200 and the grid 600 supply power to the load 500 through the grid interface 203.

[0090] When the grid-connected interface 203 outputs an alternating current, since the second normally closed auxiliary switch 40 is in a closed state, the first control loop is turned on and energized, and the first induction coil A1 can receive the output of the grid-connected interface 203, thereby generating a first electromagnetic signal (such as electromagnetic force). Under the action of the first electromagnetic signal (or under the control of the first electromagnetic signal), the first main contacts TL1 and TN1 are switched to a closed state, and the first electromagnetic switch 10 thereby conducts the grid-connected interface 203 and the load 500. At the same time, since the first normally closed auxiliary switch 30 is mechanically interlocked with the first electromagnetic switch 10, the first normally closed auxiliary switch 30 is switched to an open state, thereby disconnecting the second control loop.

[0091] It can be understood that once the second control circuit is disconnected, it is impossible to energize the second main contacts TL2 and TN2 to close, so the first electromagnetic switch 10 and the second electromagnetic switch 20 are electrically interlocked. In addition, since the first main contact TL1 is mechanically interlocked with the second main contact TL2, when the first main contact TL1 is closed, even if the second control circuit is accidentally powered after a single fault, the second main contacts TL2 and TN2 will not close and will remain in an open state.

[0092] Therefore, at this time, the AC current output by the grid-connected interface 203 is transmitted to the load 500 through the closed first main contacts TL1 and TN1. That is, at this time, at least one of the inverter 200 and the grid 600 serves as a power supply source to supply power to the load 500.

[0093] When the inverter 200 needs to operate off-grid, it may be because the power grid 600 has a power failure or other reasons. In order to ensure the safety of the power grid 600 during maintenance, the connection between the power grid 600 and the inverter 200 needs to be disconnected. Therefore, the inverter 200 at this time outputs an AC voltage through the off-grid interface 204, and the grid-connected interface 203 is powered off at this time. Therefore, the first induction coil A1 loses power and cannot generate the first electromagnetic signal, so the first main contacts TL1 and TN1 are both switched to an open state, and the first normally closed auxiliary switch 30 is switched to a closed state. Therefore, the second control loop where the second induction coil A2 and the first normally closed auxiliary switch 30 are located is connected, so the output of the off-grid interface 204 can be connected. Based on this, the second induction coil A2 can receive the output of the off-grid interface 204, thereby generating a second electromagnetic signal (such as electromagnetic force). Under the action of the second electromagnetic signal (or under the control of the second electromagnetic signal), the second main contacts TL2 and TN2 are switched to a closed state, and the second electromagnetic switch 20 thereby conducts the off-grid interface 204 and the load 500. At the same time, since the second normally closed auxiliary switch 40 and the second electromagnetic switch 20 are mechanically interlocked, the second normally closed auxiliary switch 40 is switched to an open state, thereby disconnecting the first control loop.

[0094] It can be understood that once the first control circuit is disconnected, it is impossible to energize the first main contacts TL1 and TN1 to close, so the second electromagnetic switch 20 and the first electromagnetic switch 10 are electrically interlocked. In addition, since the first main contact TL1 is mechanically interlocked with the second main contact TL2, when the second main contact TL2 is closed, even if the first control circuit is accidentally powered after a single fault, the first main contacts TL1 and TN1 will not close and will remain in an open state.

[0095] Therefore, at this time, the output of the off-grid interface 204 is transmitted to the load 500 through the closed second main contacts TL2 and TN2. That is, at this time, the inverter 200 serves as a power supply source and supplies power to the load 500 through the off-grid interface 204.

[0096] If the power grid 600 loses power first and then resumes power during the above process, since the second normally closed auxiliary switch 40 is in an open state at this time, the first control loop where the second normally closed auxiliary switch 40 and the first induction coil A1 are located cannot be turned on, so the first main contacts TL1 and TN1 remain in an open state, and the second main contacts TL2 and TN2 remain in a closed state. Therefore, the second electromagnetic switch 20 at this time keeps turning on the off-grid interface 204 and the load 500, and the second normally closed auxiliary switch 40 keeps turning off the first control loop, the inverter 200 is in an off-grid operation state, and the load 500 is still powered by the inverter 200.

[0097] Furthermore, if the subsequent inverter 200 stops outputting AC voltage through the off-grid interface 204, that is, the off-grid interface 204 is powered off, the switching device 100 can be switched to access the output of the grid-connected interface 203, so that the power grid 600 and the inverter 200 supply power to the load 500 through the grid-connected interface 203. The specific process can be found in the relevant description of the switching device 100 when the grid-connected interface 203 is output, which will not be repeated here.

[0098] It can be seen that when the power grid 600 resumes power supply, when the switching device 100 switches back to outputting to the load 500 through the grid-connected interface 203 may depend on when the off-grid interface 204 of the inverter 200 is powered off. Therefore, the inverter 200 can determine whether the power grid 600 is powered off by sampling the voltage between the phase line L and the neutral line N through the voltage sampling circuit, or sampling the voltage of the grid-connected interface 203, and then control its own operating state (that is, whether it is grid-connected operation or off-grid operation, in other words, whether it is output through the grid-connected interface 203 or output through the off-grid interface 204), thereby affecting the switching of the switching device 100. For example, the inverter 200 can stop outputting the AC voltage through the off-grid interface 204 after the power grid 600 resumes power supply for a preset period of time, so that the switching device 100 switches back to the power grid 600 providing AC current to the load 500 through the grid-connected interface 203 after the power grid 600 resumes power supply for a period of time. Such a design can ensure that the load 500 is powered only after the power supply of the power grid 600 is stable, thereby ensuring the stable and normal operation of the load 500. The preset time length can be determined according to actual conditions, for example, it can be set to 5s or other time lengths.

[0099] In addition, the neutral line N" of the inverter 200 or the first end of the second main contact TN2 in the second electromagnetic switch 20 can also be connected to a protective earth (PE, not shown in the figure). In this way, when the inverter 200 is off-grid, the power safety of the switching device 100 and the circuit connected to the switching device 100 can be further improved.

[0100] To sum up, the switching device of the embodiment of the present application can be used in conjunction with the inverter to switch the power supply for the load, and to switch the grid-connected interface load or the off-grid interface load (referred to as on-grid and off-grid load) for the inverter. The switching efficiency is high and the safety is high, which is beneficial to ensure uninterrupted power supply to the load and safe operation of the inverter.

[0101] Compared with manual two-way knife switches and professional dual-power switching switches (ATS, Automatic Transfer Switching Equipment), manual two-way knife switches require manual operation, which is troublesome to operate and has safety hazards. In addition, the switching time is long, and it is difficult to switch immediately when the power grid is out of power or restored. The ATS is expensive, and the switching is also relatively slow, generally requiring more than 1 second of switching time. The switching device of the embodiment of the present application can be composed of contactors, auxiliary contact devices, and mechanical accessories. The contactors and auxiliary contact devices are very fast in closing and separating, so the switching time of the switching device can be very short (such as within 100ms). In addition, the contactors, auxiliary contact devices, and mechanical accessories are cheap, simple in structure, and easy to integrate into one. Therefore, the switching device of the embodiment of the present application has the advantages of high switching efficiency, low cost, simple structure, easy implementation, and small space occupation.

[0102] Moreover, the switching device of the embodiment of the present application can realize mechanical interlocking and electrical interlocking between the switch from the grid side to the load side (i.e., the first electromagnetic switch) and the switch from the off-grid side to the load side (i.e., the second electromagnetic switch), wherein the mechanical interlocking can prevent the failure of the electrical interlocking from causing the switching function of the switching device to fail. And in the case of a single fault, the off-grid side voltage will not be applied to the grid side, or the grid side voltage will not be applied to the off-grid side. In this way, when the inverter is off-grid, the safety of the grid side inspection and maintenance can be guaranteed to avoid the occurrence of safety accidents. In addition, overstress of the electronic components of the inverter can also be avoided.

[0103] Please also read Figure 4 , an embodiment of the present application also provides an inverter system.

[0104] like Figure 4 As shown, the inverter system 1000 includes a switching device 100 and an inverter 200 .

[0105] The switching device 100 is connected to the inverter 200, the switching device 100 is also used to connect to the load, and the inverter 200 is also used to connect to the power grid. The switching device 100 can be the above Figures 1 to 3 The switching device 100 of the illustrated embodiment.

[0106] It can be understood that the switching device 100, the inverter 200, the power grid and the load can refer to the relevant description in the aforementioned switching device 100, which will not be repeated here.

[0107] Please also read Figure 5 , an embodiment of the present application also provides an energy storage system.

[0108] like Figure 5As shown, the energy storage system 2000 includes a switching device 100 , an inverter 200 and a battery pack 300 .

[0109] The description of the switching device 100 and the inverter 200 can be found in Figure 4 The relevant description in will not be repeated here. The battery pack 300 is connected to the inverter 200, so that it can be used to provide direct current to the inverter 200. The inverter 200 can then convert the direct current provided by the battery pack 300 into alternating current, and transmit the alternating current to the load connected to the inverter 200 through the switching device 100. It is understandable that based on such a structure, the energy storage system can also be called an energy storage inverter system.

[0110] certainly, Figure 5 The illustrated energy storage system 2000 does not constitute a specific limitation on the energy storage system 2000 of the embodiment of the present application. In some cases, the energy storage system may further include more or fewer devices, equipment, modules, circuits or components than those shown in the figure.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A switching device, characterized in that: include: A first electromagnetic switch, a second electromagnetic switch, a first normally closed auxiliary switch, and a second normally closed auxiliary switch; The first electromagnetic switch is used to connect the second normally closed auxiliary switch, the grid-connected interface of the inverter and the load, wherein the grid-connected interface is used to connect to the power grid; the second normally closed auxiliary switch is used to connect to the grid-connected interface, thereby forming a first control loop together with the grid-connected interface and the first electromagnetic switch; The second electromagnetic switch is used to connect the first normally closed auxiliary switch, the off-grid interface of the inverter and the load; the first normally closed auxiliary switch is used to connect to the off-grid interface, thereby forming a second control loop together with the off-grid interface and the second electromagnetic switch; Wherein, the first electromagnetic switch is mechanically interlocked with the first normally closed auxiliary switch, the first electromagnetic switch is mechanically interlocked with the second electromagnetic switch, and the second electromagnetic switch is mechanically interlocked with the second normally closed auxiliary switch; The first control loop is used to control the first electromagnetic switch to close when the inverter is in grid-connected operation, so as to conduct the grid-connected interface and the load, and to control the first normally closed auxiliary switch to open, so as to disconnect the second control loop, so that the inverter and the grid supply power to the load through the grid-connected interface; The second control loop is used to control the second electromagnetic switch to close when the inverter is operating off-grid to connect the off-grid interface and the load, and to control the second normally closed auxiliary switch to open to disconnect the first control loop, so that the inverter supplies power to the load through the off-grid interface.

2. The switching device according to claim 1, characterized in that: The first electromagnetic switch comprises a first main contact and a first induction coil, wherein the first main contact is connected between the grid-connected interface and the load, the first induction coil is connected in series with the second normally closed auxiliary switch, and the first induction coil and the second normally closed auxiliary switch are also connected to the grid-connected interface, thereby forming the first control loop together with the grid-connected interface; The second electromagnetic switch includes a second main contact and a second induction coil, wherein the second main contact is connected between the off-grid interface and the load, the second induction coil is connected in series with the first normally closed auxiliary switch, and the second induction coil and the first normally closed auxiliary switch are also connected to the off-grid interface, thereby forming the second control loop together with the off-grid interface.

3. The switching device according to claim 2, characterized in that: The first main contact is mechanically interlocked with the first normally closed auxiliary switch, the first main contact is mechanically interlocked with the second main contact, and the second main contact is mechanically interlocked with the second normally closed auxiliary switch; The first control circuit is used to energize when the inverter is in grid-connected operation, so that the first induction coil generates a first electromagnetic signal, and the first electromagnetic signal is used to control the first main contact to close, so as to conduct the grid-connected interface and the load; when the first main contact is closed, the first normally closed auxiliary switch is opened to disconnect the second control circuit; The second control circuit is used to energize when the inverter is operating off-grid, so that the second induction coil generates a second electromagnetic signal, and the second electromagnetic signal is used to control the closing of the second main contact to conduct the off-grid interface and the load; when the second main contact is closed, the second normally closed auxiliary switch is opened to disconnect the first control circuit.

4. The switching device according to claim 2, characterized in that: The first induction coil is connected to one of the phase line and the neutral line of the grid-connected interface, and the second normally closed auxiliary switch is connected to the other of the phase line and the neutral line of the grid-connected interface; The first main contact includes a first phase line main contact and a first neutral line main contact, wherein the first phase line main contact is connected to the phase line of the grid-connected interface in a one-to-one correspondence, and the first neutral line main contact is connected to the neutral line of the grid-connected interface in a corresponding manner.

5. The switching device according to claim 2, characterized in that: The second induction coil is connected to one of the phase line and the neutral line of the off-grid interface, and the first normally closed auxiliary switch is connected to the other of the phase line and the neutral line of the off-grid interface; The second main contact includes a second phase line main contact and a second neutral line main contact, wherein the second phase line main contact is connected to the phase line of the off-grid interface in a one-to-one correspondence, and the second neutral line main contact is connected to the neutral line of the off-grid interface in a corresponding manner.

6. The switching device according to claim 1, characterized in that: The switching device further includes a mechanical interlocking accessory, which is disposed between the first electromagnetic switch and the second electromagnetic switch and mechanically connects the first electromagnetic switch and the second electromagnetic switch into one, and mechanically interlocks the first electromagnetic switch and the second electromagnetic switch.

7. The switching device according to claim 1, characterized in that: The first normally closed auxiliary switch is installed on the first electromagnetic switch, and the second normally closed auxiliary switch is installed on the second electromagnetic switch.

8. The switching device according to claim 1, characterized in that: The first electromagnetic switch and the second electromagnetic switch use AC contactors, and the first normally closed auxiliary switch and the second normally closed auxiliary switch use normally closed auxiliary contacts; The rated voltages of the first electromagnetic switch, the second electromagnetic switch, the first normally closed auxiliary switch and the second normally closed auxiliary switch are all within the grid voltage range.

9. An inverter system, characterized in that: The inverter system includes an inverter and a switching device as described in any one of claims 1 to 8, the inverter is connected to the switching device, the switching device is also used to be connected to a load, and the inverter is used to output AC power to the load through the switching device.

10. An energy storage system, characterized in that: The energy storage system includes a battery pack, an inverter and a switching device as described in any one of claims 1 to 8, wherein the battery pack and the switching device are both connected to the inverter, and the switching device is also used to be connected to a load. The inverter is used to convert the direct current provided by the battery pack into alternating current, and output the alternating current to the load through the switching device.

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