Inverter

Abstract

Provided in the present application is an inverter. The inverter comprises an inverter circuit, at least one relay, and an output port for connecting to an alternating-current power grid, wherein the inverter circuit comprises at least two alternating-current output terminals; each relay comprises a coil, a contact assembly, a connecting rod assembly and a driving apparatus, the contact assembly comprising a stationary contact and a movable contact; and at least one alternating-current output terminal is connected to the output port by means of the contact assembly in the at least one relay. In each relay, the movable contact is in transmission connection with the coil; both the movable contact and the driving apparatus are in transmission connection with the connecting rod assembly; and when an internal short circuit occurs in the inverter, the driving apparatus drives the connecting rod assembly to move, such that the connecting rod assembly drives the movable contact to be separated from the stationary contact and that an opening distance is a first opening distance, wherein the first opening distance is greater than or equal to a second opening distance, and the second opening distance is an opening distance when the movable contact is driven to be separated from the stationary contact after the coil is de-energized under normal conditions of the inverter. On the basis of the present application, the engineering installation volume of an inverter can be reduced, and the overall cost can be lowered.

Description

Inverter

[0001] This application claims priority to Chinese Patent Application No. 202411999988.7, filed with the China National Intellectual Property Administration on December 31, 2024, entitled "Inverter", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photovoltaic power generation technology, and in particular to an inverter. Background Technology

[0003] With the development of photovoltaic (PV) panels, the capacity of PV power plants is increasing, and PV inverters are becoming widely used in large-scale PV power plants, becoming the mainstream power generation equipment in the PV industry. PV inverters are used to convert the DC power output from PV strings into AC power, which is then supplied to the grid through prefabricated substations. When a short circuit occurs inside the PV inverter (such as a DC bus short circuit or a partial short circuit in the inverter circuit), the AC grid will backflow current into the PV inverter. In this case, the PV inverter needs to rely on the molded case circuit breaker (MCCB) inside the prefabricated substation to interrupt the backflow current from the AC grid. However, the MCB may generate an electric arc during the interruption process, causing the fault to propagate to the upstream prefabricated substation. Therefore, how to interrupt the backflow current from the AC grid inside the PV inverter to ensure that its own fault does not propagate to upstream equipment (such as the prefabricated substation) becomes particularly important.

[0004] Currently, fuses or circuit breakers are typically added to the main power circuit of photovoltaic inverters to interrupt reverse current from the AC grid. However, fuses or circuit breakers are large and expensive, resulting in excessively large installation size and overall high cost for photovoltaic inverters. Summary of the Invention

[0005] This application provides an inverter that can reuse the original coil and contact assembly of a relay, and avoids the need to add a fuse or circuit breaker outside the relay by setting a linkage assembly and drive device inside the relay, thereby reducing the engineering installation volume of the inverter and reducing the overall cost of the inverter.

[0006] In a first aspect, embodiments of this application provide an inverter, which includes an inverter circuit, at least one relay, and an output port. The inverter circuit includes at least two AC output terminals. Each of the at least one relay includes a coil, a contact assembly, a linkage assembly, and a drive device. The contact assembly includes a stationary contact and a moving contact. At least one of the at least two AC output terminals is connected to the output port via the contact assembly in the at least one relay, and the output port is used to connect to the AC power grid. In each relay, the moving contact in the contact assembly is drivenly connected to the coil, and the moving contact in the contact assembly and the drive device are respectively drivenly connected to the linkage assembly. In the event of an internal short circuit in the inverter, the AC power grid will backflow current into the inverter. At this time, the drive device is used to drive the linkage assembly to move, so that the linkage assembly causes the moving contact in the contact assembly to separate from the stationary contact and set the opening distance between the moving contact and the stationary contact to a first opening distance. The first opening distance is greater than or equal to the second opening distance, which is the opening distance between the moving and stationary contacts in the drive contact assembly when the coil is de-energized under normal inverter conditions. It should be understood that since the opening distance is related to the relay's arc-extinguishing capability, when the first opening distance is greater than or equal to the second opening distance, the larger first opening distance will cause the arc generated when the moving and stationary contacts separate to be extinguished quickly, thereby safely disconnecting the reverse current (or fault current) from the AC power grid.

[0007] By implementing the embodiments of this application, the original coil and contact assembly of the relay can be reused. By setting up a linkage assembly and drive device inside the relay, the need for adding a fuse or circuit breaker outside the relay or setting up a larger coil inside the relay is avoided, thereby reducing the engineering installation size of the inverter and lowering the overall cost of the inverter. In addition, safe interruption of reverse current from the AC grid can be achieved inside the inverter, significantly improving the inverter's safety, thereby enhancing the power supply safety and equipment lifespan. Furthermore, during this interruption process, the relay implements short-circuit interruption protection and arc extinguishing functions, making the relay's functionality more diverse.

[0008] In one possible implementation, the inverter further includes a controller. The controller is used to energize the control coil to drive the moving contact in the contact assembly to engage with the stationary contact when the inverter is operating normally, or to de-energize the control coil to drive the moving contact in the contact assembly to disengage to a second opening distance. By implementing the embodiments of this application, the moving contact in the contact assembly can be driven to engage or disengage with the stationary contact through the control coil, making the relay control method simpler.

[0009] In one possible implementation, when the driving device is an electromagnetic device, the controller outputs a drive signal to the electromagnetic device upon detecting an internal short circuit in the inverter. Further, upon receiving the drive signal, the electromagnetic device drives the linkage assembly to move, causing the linkage assembly to separate the moving contact from the stationary contact in the contact assembly and setting the distance between the moving and stationary contacts to a first distance. By implementing the embodiments of this application, controlling the electromagnetic device with the controller can shorten the response time when the electromagnetic device drives the linkage assembly, thereby quickly interrupting the backflow current from the AC power grid.

[0010] In one possible implementation, when the driving device is a magnetic trip device, the magnetic trip device is used to drive the linkage assembly to move when a short circuit is detected inside the inverter. This causes the linkage assembly to separate the moving contact from the stationary contact in the contact assembly, setting the opening distance between the moving and stationary contacts to a first opening distance. Implementing this embodiment, since the magnetic trip device has the function of detecting the main circuit current (such as the current flowing through the contact assembly), it can directly detect the magnitude of the current flowing through the contact assembly to determine whether there is a short circuit inside the inverter. This eliminates the need for a separate current detection device inside the inverter to detect the current flowing through the contact assembly, further reducing the inverter's installation size and overall cost. Furthermore, there is no need for other equipment to control the magnetic trip device to drive the linkage assembly, simplifying the driving method.

[0011] In one possible implementation, each of the above relays further includes an arc-extinguishing device. When the linkage assembly or coil causes the moving contact to separate from the stationary contact, an electric arc is generated between the moving and stationary contacts. At this time, the arc-extinguishing device is used to extinguish the arc generated when the moving contact separates from the stationary contact in the contact assembly, thereby improving the stability and safety of the relay and further enhancing the safety of the inverter.

[0012] In one possible implementation, the inverter includes at least two relays, each relay including a contact assembly, and at least a portion of the at least two AC output terminals correspond one-to-one with the at least two relays. Each of the at least a portion of the AC output terminals is connected to an output port via a contact assembly in its corresponding relay. It can be understood that when the inverter is a single-phase inverter with two AC output terminals, the number of at least a portion of the AC output terminals and at least two relays can be two. When the inverter is a three-phase three-wire inverter with three AC output terminals, the number of at least a portion of the AC output terminals and at least two relays can be three. When the inverter is a three-phase four-wire inverter with four AC output terminals, the number of at least a portion of the AC output terminals and at least two relays can be three or four. By implementing the embodiments of this application, the number of at least two relays can be flexibly adjusted according to the actual structure of the inverter, resulting in more diverse circuit topologies for the inverter.

[0013] In one possible implementation, the inverter includes a relay with at least two contact assemblies, and at least a portion of the at least two AC output terminals correspond one-to-one with the at least two contact assemblies. Each of the at least a portion of the AC output terminals is connected to an output port via a corresponding contact assembly. It can be understood that when the inverter is a single-phase inverter and the inverter circuit includes two AC output terminals, the number of at least a portion of the AC output terminals and at least two contact assemblies can be two. When the inverter is a three-phase three-wire inverter and the inverter circuit includes three AC output terminals, the number of at least a portion of the AC output terminals and at least two contact assemblies can be three. When the inverter is a three-phase four-wire inverter and the inverter circuit includes four AC output terminals, the number of at least a portion of the AC output terminals and at least two contact assemblies can be three or four. By implementing the embodiments of this application, the number of at least two contact assemblies can be flexibly adjusted according to the actual structure of the inverter, resulting in more diverse inverter circuit topologies.

[0014] In one possible implementation, when the linkage assembly includes an elastic element and a linkage mechanism, the aforementioned driving device is specifically used to drive the elastic element to release energy to push the linkage mechanism. Further, the linkage mechanism is specifically used to, under the pushing action of the elastic element, cause the moving contact in the contact assembly to separate from the stationary contact and make the opening distance between the moving contact and the stationary contact a first opening distance. By implementing the embodiments of this application, the use of an elastic element and a linkage mechanism can improve the load-bearing capacity and impact resistance of the linkage assembly, and the structure of the linkage assembly is simpler and the cost is lower.

[0015] In one possible implementation, when the linkage assembly includes an elastic element, a linkage mechanism, and a switch, the aforementioned driving device is specifically used to drive the elastic element to release energy to push the linkage mechanism. Further, the linkage mechanism is specifically used to release the switch inserted between the moving and stationary contacts in the contact assembly under the push of the elastic element, so that the moving and stationary contacts in the contact assembly are separated and the opening distance between the moving and stationary contacts is a first opening distance. By implementing the embodiments of this application, the use of an elastic element, a linkage mechanism, and a switch can improve the load-bearing capacity and impact resistance of the linkage assembly, and the linkage assembly has a simple structure and is easy to operate.

[0016] In one possible implementation, if the inverter also includes a current detection device, the current detection device is used to detect the current flowing through the contact assembly. Further, the controller is used to determine an internal short circuit in the inverter if the current flowing through the contact assembly is greater than or equal to a preset current value. Implementing the embodiments of this application allows for rapid determination of whether there is an internal short circuit in the inverter by measuring the current flowing through the contact assembly, simplifying the short circuit determination method.

[0017] In one possible implementation, the current detection device can be connected between the inverter circuit and the moving contact in the contact assembly, or between the stationary contact in the contact assembly and the output port, making the connection method of the current detection device more flexible.

[0018] In one possible implementation, when the inverter is a three-phase four-wire inverter, the inverter includes three relays, each of which includes a contact assembly. The inverter circuit includes four AC output terminals, three of which correspond one-to-one with the three relays. Each of the three AC output terminals is connected to an output port through a contact assembly in its corresponding relay. By implementing this embodiment, the number of relays can be flexibly adjusted according to the actual structure of the inverter to meet the requirement of interrupting backflow current from the AC power grid. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the photovoltaic system provided in an embodiment of this application;

[0020] Figure 2 is a circuit diagram of an inverter provided in an embodiment of this application;

[0021] Figure 3 is another circuit diagram of the inverter provided in an embodiment of this application;

[0022] Figures 4A and 4B are another circuit diagram of the inverter provided in the embodiment of this application;

[0023] Figure 5 is another circuit diagram of the inverter provided in an embodiment of this application;

[0024] Figure 6 is another circuit diagram of the inverter provided in an embodiment of this application;

[0025] Figure 7 is another circuit diagram of the inverter provided in an embodiment of this application;

[0026] Figure 8 is another circuit diagram of the inverter provided in an embodiment of this application;

[0027] Figure 9 is another circuit diagram of the inverter provided in an embodiment of this application;

[0028] Figure 10 is another circuit diagram of the inverter provided in an embodiment of this application;

[0029] Figure 11 is another circuit diagram of the inverter provided in an embodiment of this application;

[0030] Figure 12 is another circuit diagram of the inverter provided in an embodiment of this application;

[0031] Figure 13 is another circuit diagram of the inverter provided in an embodiment of this application;

[0032] Figure 14 is another circuit diagram of the inverter provided in an embodiment of this application;

[0033] Figure 15 is another circuit diagram of the inverter provided in an embodiment of this application;

[0034] Figure 16 is another circuit diagram of the inverter provided in an embodiment of this application;

[0035] Figure 17 is another circuit diagram of the inverter provided in an embodiment of this application;

[0036] Figure 18 is another circuit diagram of the inverter provided in an embodiment of this application;

[0037] Figure 19 is another circuit diagram of the inverter provided in an embodiment of this application;

[0038] Figure 20 is another circuit diagram of the inverter provided in an embodiment of this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] The implementation of the technical solution of this application will be further described in detail below with reference to the accompanying drawings.

[0041] Referring to Figure 1, which is a schematic diagram of the photovoltaic system provided in an embodiment of this application, the photovoltaic system includes an inverter 12 and a prefabricated substation 13. The inverter 12 includes DC-DC converter circuits 121a to 121n, an inverter circuit 122, a relay 123, and an output port 124. Each DC-DC converter circuit has two DC input terminals for connecting to each photovoltaic string in at least one photovoltaic string, and each photovoltaic string can be composed of at least one photovoltaic module connected in series. For example, one DC input terminal of DC-DC converter 121a is used to connect to the positive terminal of photovoltaic string 11a, and the other DC input terminal of DC-DC converter 121a is used to connect to the negative terminal of photovoltaic string 11a, ..., one DC input terminal of DC-DC converter 121n is used to connect to the positive terminals of photovoltaic string 11b and photovoltaic string 11c, and the other DC input terminal of DC-DC converter 121n is used to connect to the negative terminals of photovoltaic string 11b and photovoltaic string 11c. The two DC output terminals of each DC-DC converter are connected to the two DC input terminals of inverter circuit 122. The inverter circuit 122 includes four AC output terminals: an L1-phase AC output terminal, an L2-phase AC output terminal, an L3-phase AC output terminal, and a neutral (N) line AC output terminal. The L1-phase AC output terminal is connected to output port 124 via contact assembly 1231 in relay 123; the L2-phase AC output terminal is connected to output port 124 via contact assembly 1232 in relay 123; the L3-phase AC output terminal is connected to output port 124 via contact assembly 1233 in relay 123; and the neutral (N) line AC output terminal is connected to output port 124. The output port 124 of the inverter 12 is connected to the input terminal of the prefabricated substation 13, and the output terminal of the prefabricated substation 13 is used to connect to the AC power grid 14.

[0042] When the photovoltaic system receives DC power, each DC-DC converter circuit converts the DC power output from its connected photovoltaic string into electrical energy and outputs DC power to the inverter circuit 122. Further, the inverter circuit 122 converts the DC power output from each DC-DC converter circuit into AC power and outputs AC power to the prefabricated substation 13 when the moving and stationary contacts in contact assemblies 1231, 1232, and 1233 are all engaged. Even further, the prefabricated substation 13 transforms the AC power output from the inverter circuit 122 and supplies it to the AC power grid 14.

[0043] In the event of an internal short circuit in inverter 12, the AC voltage output by inverter circuit 122 drops significantly or even to zero, resulting in a reverse current flowing from AC grid 14 into inverter 12 via substation 13. To interrupt this reverse current from AC grid 14 within inverter 12, this embodiment adds a linkage assembly and a drive device to the existing coil and three contact assemblies of relay 123. Each of the three contact assemblies (contact assembly 1231, contact assembly 1232, and contact assembly 1233) includes a moving contact and a stationary contact. The moving contact in each contact assembly is driven by the coil, and the moving contact and drive device in each contact assembly are driven by the linkage assembly. The aforementioned drive device is used to drive the linkage assembly to move in the event of a short circuit inside the inverter 12, so that the linkage assembly causes the moving contact in each contact assembly to separate from the stationary contact and establish a first opening distance between the moving and stationary contacts in each contact assembly, thereby interrupting the reverse current from the AC power grid 14. The first opening distance is greater than or equal to a second opening distance, which is the opening distance between the moving and stationary contacts when the coil is de-energized under normal inverter 12 conditions, driving the moving contact in each contact assembly to separate from the stationary contact. Here, the opening distance refers to the minimum distance between the moving and stationary contacts when they separate.

[0044] By implementing the embodiments of this application, the reverse current from the AC grid 14 can be quickly interrupted inside the inverter 12, preventing the short-circuit fault of the inverter 12 itself from spreading to the upper-level equipment (such as the box-type substation 13), thereby reducing the impact of the short-circuit fault on the box-type substation 13, and thus reducing the equipment failure rate of the photovoltaic system to extend the service life of the equipment.

[0045] The inverter provided in this application and its working principle will be illustrated below with reference to Figures 2 to 20.

[0046] Referring to Figure 2, which is a circuit diagram of an inverter provided in an embodiment of this application, when the inverter is a single-phase inverter and includes a relay, the specific structure can be as shown in Figure 2. The inverter 2 includes an inverter circuit 21, a relay K1, and an output port out. The inverter circuit 21 includes two AC output terminals, specifically an L-phase AC output terminal and a N-line AC output terminal. The relay K1 includes a coil Y1, a contact assembly CT11, a linkage assembly 221, and a drive device 222. The contact assembly CT11 includes a moving contact MC11 and a stationary contact SC11. The L-phase AC output terminal is connected to the output port out through the contact assembly CT11, and the N-line AC output terminal is connected to the output port out. The output port out is used to connect to the AC power grid 3. The moving contact MC11 in the contact assembly CT11 is drivenly connected to the coil Y1, and the moving contact MC11 and the drive device 222 are drivenly connected to the linkage assembly 221, respectively.

[0047] Under normal operating conditions, inverter circuit 21 inverts DC power and outputs AC power. The aforementioned coil Y1 drives the moving contact MC11 and stationary contact SC11 in the contact assembly CT11 to engage after energization. At this time, the AC power output by inverter circuit 21 can be transmitted to the output port out through the moving contact MC11 and stationary contact SC11. Furthermore, the output port out is used to output AC power to the AC power grid 3.

[0048] In the event of a short circuit inside inverter 2, such as a short circuit in the internal wiring or components, the AC voltage output at the output port OUT drops significantly or even becomes zero, causing the AC grid 3 to backflow current into inverter 2. At this time, the drive device 222 drives the linkage assembly 221 to move, causing the linkage assembly 221 to separate the moving contact MC11 from the stationary contact SC11 in the contact assembly CT11, establishing a first opening distance between the moving contact MC11 and the stationary contact SC11. The first opening distance is greater than or equal to a second opening distance, which is the opening distance between the moving contact MC11 and the stationary contact SC11 when the coil Y1 is de-energized under normal inverter 2 conditions, causing the moving contact MC11 to separate from the stationary contact SC11 in the contact assembly CT11. It should be understood that since the contact gap is related to the arc extinguishing capability of relay K1, when the first gap is greater than or equal to the second gap, the larger first gap will cause the arc generated when the moving contact separates from the stationary contact to be extinguished quickly, thereby safely disconnecting the reverse current from AC power grid 3.

[0049] By implementing the embodiments of this application, the original coil Y1 and contact assembly CT11 of relay K1 can be reused. By setting the linkage assembly 221 and drive device 222 inside relay K1, the need to add a fuse or circuit breaker outside relay K1 or to install a larger coil inside relay K1 is avoided, thereby reducing the engineering installation volume of inverter 2 and lowering the overall cost of inverter 2. Furthermore, safe disconnection of reverse current from AC grid 3 can be achieved inside inverter 2, significantly improving the safety of inverter 2, thereby enhancing the power supply safety and equipment lifespan of inverter 2. Moreover, during this disconnection process, relay K1 implements short-circuit disconnection protection and arc extinguishing functions, making the functions of relay K1 more diverse.

[0050] It is understandable that when inverter 2 is normal and coil Y1 is de-energized, driving the moving contact MC11 to separate from the stationary contact SC11, the second gap between the moving contact MC11 and the stationary contact SC11 is usually relatively small (e.g., 2mm-3mm). Since the current flowing through the contact assembly CT11 is small when inverter 2 is normal, the small second gap can extinguish the arc generated when the moving contact MC11 separates from the stationary contact SC11. However, when inverter 2 is internally short-circuited and the linkage assembly 221 and drive device 222 are not installed inside relay K1, a larger coil Y1 is usually used inside relay K1 to ensure that the second gap between the moving contact MC11 and the stationary contact SC11 is large enough (e.g., 10mm-20mm) when coil Y1 is de-energized, thereby extinguishing the arc generated when the moving contact MC11 separates from the stationary contact SC11, and thus safely disconnecting the reverse current from AC grid 3. However, directly using a larger coil Y1 would increase the size and cost of relay K1. Therefore, this embodiment does not change the size of coil Y1, but instead uses a smaller and lower-cost linkage assembly 221 and drive device 222 inside relay K1 to separate the moving contact MC11 from the stationary contact SC11 and make the opening distance between the moving contact MC11 and the stationary contact SC11 a first opening distance (e.g., 10mm-20mm). This reduces the size and cost of relay K1, thereby reducing the engineering installation volume of inverter 2 and lowering the overall cost of inverter 2.

[0051] As shown in Figure 3, the inverter 2 shown in Figure 2 also includes a controller 23. The controller 23 is used to energize the coil Y1 under normal operating conditions to drive the moving contact MC11 in the contact assembly CT11 to engage with the stationary contact SC11, or to de-energize the coil Y1 to drive the moving contact MC11 in the contact assembly CT11 to disengage to the second opening distance. Specifically, the inverter 2 shown in Figure 2 also includes a switch Q1 and a power supply 24, with the coil Y1 connected to the power supply 24 via the switch Q1. Under normal operating conditions, the controller 23 controls the switch Q1 to conduct, allowing the power supply 24 to energize the coil Y1, at which point the coil Y1 can drive the moving contact MC11 in the contact assembly CT11 to engage with the stationary contact SC11. The controller 23 also controls the switch Q1 to de-energize, stopping the power supply 24 from energizing the coil Y1, at which point the coil Y1 is de-energized and drives the moving contact MC11 in the contact assembly CT11 to disengage from the stationary contact SC11. This application embodiment does not limit the location of the power supply 24; for example, the power supply 24 can also be located outside the inverter 2. Implementing this application embodiment, the moving contact MC11 and the stationary contact SC11 can be driven to engage or disengage via the control coil Y1, making the control method of the relay K1 simpler.

[0052] When the inverter 2 shown in Figure 2 further includes a controller 23 and a current detection device 25, the specific structure can be shown in Figures 4A and 4B. In Figure 4A, the current detection device 25 is connected between the inverter circuit 21 and the moving contact MC11 in the contact assembly CT11. In Figure 4B, the current detection device 25 is connected between the stationary contact SC11 in the contact assembly CT11 and the output port out. These are just examples, and the connection position of the current detection device 25 is not limited in this embodiment. When a short circuit occurs inside the inverter 2, causing the AC grid 3 to backflow current into the inverter 2, the current flowing through the contact assembly CT11 will increase instantaneously. If it is greater than or equal to a preset current value, this embodiment can determine whether there is a short circuit inside the inverter 2 by the magnitude of the current flowing through the contact assembly CT11. In specific implementation, the current detection device 25 is used to detect the current flowing through the contact assembly CT11. The controller 23 can establish a communication connection with the current detection device 25 to obtain the current flowing through the contact assembly CT11. Furthermore, the controller 23 is used to determine an internal short circuit in the inverter 2 when the current flowing through the contact assembly CT11 is greater than or equal to a preset current value. The preset current value is greater than the rated current of the inverter 2. For example, the preset current value can be five times the rated current of the inverter 2. By implementing this embodiment, the magnitude of the current flowing through the contact assembly CT11 can be used to quickly determine whether there is an internal short circuit in the inverter 2, making the short circuit determination method simpler.

[0053] The aforementioned drive device 222 refers to a control device capable of driving the linkage assembly 221 to move. For example, the drive device 222 may be an electromagnetic device or a magnetic tripping device.

[0054] For example, as shown in FIG. 5, the inverter 2 shown in FIG. 2 further includes a controller 23, and the drive device 222 is an electromagnetic device 2221. The controller 23 is used to output a drive signal to the electromagnetic device 2221 when a short circuit is detected inside the inverter 2. Further, the electromagnetic device 2221 is used to drive the linkage assembly 221 to move when it receives the drive signal, so that the linkage assembly 221 drives the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11 and make the opening distance between the moving contact MC11 and the stationary contact SC11 a first opening distance. It should be understood that the electromagnetic device 2221 generates a magnetic field when it receives the drive signal, and the magnetic field acts on the linkage assembly 221 to drive the linkage assembly 221 to move. By implementing the embodiments of this application, when the inverter 2 is short-circuited inside, the controller 23 controls the electromagnetic device 2221 to shorten the response time when the electromagnetic device 2221 drives the linkage assembly 221 to move, thereby quickly interrupting the reverse current from the AC power grid 3.

[0055] For example, as shown in Figure 6, the driving device 222 shown in Figure 2 is a magnetic tripping device 2222. The magnetic tripping device 2222 is used to drive the linkage assembly 221 to move when a short circuit is detected inside the inverter 2, so that the linkage assembly 221 causes the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11, and the opening distance between the moving contact MC11 and the stationary contact SC11 is a first opening distance. It should be understood that the magnetic tripping device 2222 has the function of detecting the main circuit current (such as the current flowing through the contact assembly CT11). Therefore, when the current flowing through the contact assembly CT11 is greater than or equal to the tripping current value of the magnetic tripping device 2222 (such as the preset current value mentioned above), that is, when there is a short circuit inside the inverter 2, the magnetic tripping device 2222 will generate a sufficiently strong magnetic field to drive the linkage assembly 221 to move. By implementing the embodiments of this application, since the magnetic trip device 2222 has the function of detecting the main circuit current, it can directly detect the magnitude of the current flowing through the contact assembly CT11 to determine whether there is a short circuit inside the inverter 2. This eliminates the need for a separate current detection device inside the inverter 2 to detect the current flowing through the contact assembly CT11, further reducing the engineering installation volume of the inverter 2 and lowering its overall cost. Furthermore, there is no need for other devices (such as controller 23) to control the magnetic trip device 2222 to drive the linkage assembly 221, making the driving method simpler.

[0056] The aforementioned linkage assembly 221 refers to an assembly capable of separating the moving contact from the stationary contact in the contact assembly and making the opening distance between the moving contact and the stationary contact a first opening distance. For example, the linkage assembly 221 may be composed of an elastic element (such as an energy storage spring) and a linkage mechanism, or it may be composed of an elastic element, a linkage mechanism, and a switch.

[0057] For example, as shown in FIG. 7, the linkage assembly 221 shown in FIG. 5 includes an elastic element 2211 and a linkage mechanism 2212. When the electromagnetic device 2221 receives a drive signal, it generates a magnetic field to drive the elastic element 2211 to release energy, thereby pushing the linkage mechanism 2212. The energy can be the energy stored in the elastic element 2211 when it is compressed or stretched. Further, the linkage mechanism 2212 is used to drive the moving contact MC11 and the stationary contact SC11 in the contact assembly CT11 to separate under the push of the elastic element 2211, and to make the opening distance between the moving contact MC11 and the stationary contact SC11 a first opening distance. The length and stroke of the linkage mechanism 2212 can be determined by the first opening distance. By implementing the embodiments of this application, the use of the elastic element 2211 and the linkage mechanism 2212 can improve the load-bearing capacity and impact resistance of the linkage assembly 221, and the structure of the linkage assembly 221 is simpler and the cost is lower.

[0058] For example, as shown in FIG8, the linkage assembly 221 shown in FIG5 includes an elastic element 2211, a linkage mechanism 2212, and a switch 2213. When the electromagnetic device 2221 receives a drive signal, it generates a magnetic field to drive the elastic element 2211 to release energy, thereby pushing the linkage mechanism 2212. Further, the linkage mechanism 2212 is used to release the switch 2213 inserted between the moving contact MC11 and the stationary contact SC11 in the contact assembly CT11 under the push of the elastic element 2211, so that the moving contact MC11 and the stationary contact SC11 in the contact assembly CT11 are separated and the opening distance between the moving contact MC11 and the stationary contact SC11 is a first opening distance. By implementing the embodiments of this application, the use of the elastic element 2211, the linkage mechanism 2212, and the switch 2213 can improve the load-bearing capacity and impact resistance of the linkage assembly 221. The linkage assembly 221 has a simple structure and is easy to operate.

[0059] It is understood that the specific structure and working principle of the linkage assembly 221 shown in Figure 6 above can be found in Figures 7 and 8 above and their corresponding embodiments, and will not be repeated here.

[0060] When the connecting rod assembly 221 or the coil Y1 causes the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11, an electric arc will be generated between the moving contact MC11 and the stationary contact SC11. To quickly extinguish the arc between the moving contact MC11 and the stationary contact SC11, an arc-extinguishing device 223 can be provided in the relay K1 shown in Figure 7. The specific structure is shown in Figure 9. The arc-extinguishing device 223 is located between the moving contacts MC11 and SC11 and is used to extinguish the arc generated when the moving contact MC11 separates from the stationary contact SC11 in the contact assembly CT11. The arc-extinguishing device 223 is a device used to control and extinguish the arc generated in electrical equipment with high voltage (such as the relay K1). For example, the arc-extinguishing device 223 can be an arc-extinguishing grid or an arc-extinguishing contact. The number of arc-extinguishing grids or arc-extinguishing contacts can be determined by the number of contact assemblies in the relay K1 and is not limited here. The above are merely examples, and the embodiments of this application do not limit the specific location and structure of the arc extinguishing device 223 in the relay K1. Implementing the embodiments of this application can quickly extinguish the arc between the moving contact MC11 and the stationary contact SC11, improving the stability and safety of the relay K1, and further enhancing the safety of the inverter 2.

[0061] It is understood that the relay K1 shown in Figures 6 and 8 above can also be equipped with an arc extinguishing device 223. The location and function of the arc extinguishing device 223 can be found in Figure 9 above and its corresponding embodiment, and will not be described again here.

[0062] When the inverter is a single-phase inverter and includes a relay, the relay K1 shown in Figure 2 can be replaced by the relay K2 shown in Figure 10. In this case, the L-phase AC output terminal of the inverter circuit 21 is connected to the output port out, and the N-line AC output terminal of the inverter circuit 21 is connected to the output port out through the contact assembly CT2 in the corresponding relay K2. The specific structure of the relay K2 can be found in the description of the specific structure of the relay K1 in the embodiments corresponding to Figures 2 to 9, and will not be repeated here. When the inverter 2 is internally short-circuited, the moving contact MC2 in the contact assembly CT2 separates from the stationary contact SC2, and the opening distance between the moving contact MC2 and the stationary contact SC2 is the first opening distance. The specific process can be found in the description of the separation of the moving contact MC11 from the stationary contact SC11 and the opening distance between the moving contact MC11 and the stationary contact SC11 being the first opening distance in the embodiments corresponding to Figures 2 to 9, and will not be repeated here.

[0063] When the inverter is a single-phase inverter and includes two relays, the specific structure can also be as shown in Figure 11. The inverter 2 shown in Figure 2 also includes relay K2. The L-phase AC output terminal corresponds to relay K1, and the N-line AC output terminal corresponds to relay K2. The L-phase AC output terminal is connected to the output port OUT through the contact assembly CT11 in the corresponding relay K1, and the N-line AC output terminal is connected to the output port OUT through the contact assembly CT2 in the corresponding relay K2. The specific structure of relay K2 can be found in the description of the specific structure of relay K1 in the embodiments corresponding to Figures 2 to 9 above, and will not be repeated here. When the inverter 2 is internally short-circuited, the moving contact MC11 separates from the stationary contact SC11 and the distance between the moving contact MC11 and the stationary contact SC11 is the first distance. The moving contact MC2 separates from the stationary contact SC2 and the distance between the moving contact MC2 and the stationary contact SC2 is the first distance. For details, please refer to the descriptions in the embodiments corresponding to Figures 2 to 9 above regarding the separation of the moving contact MC11 from the stationary contact SC11 and the distance between the moving contact MC11 and the stationary contact SC11 being the first distance. These details will not be repeated here.

[0064] When the inverter is a single-phase inverter and includes a relay, relays K1 and K2 shown in Figure 11 can be replaced with relay K1 shown in Figure 12. In this case, relay K1 includes two contact assemblies, specifically contact assembly CT11 and contact assembly CT12. The L-phase AC output terminal corresponds to contact assembly CT11, and the N-line AC output terminal corresponds to contact assembly CT12. The L-phase AC output terminal is connected to the output port OUT through the corresponding contact assembly CT11, and the N-line AC output terminal is connected to the output port OUT through the corresponding contact assembly CT12. The moving contact MC11 in contact assembly CT11 and the moving contact MC12 in contact assembly CT12 are both connected to coil Y1. The moving contacts MC11 and MC12, and the drive device 222 are respectively connected to the linkage assembly 221. When the inverter 2 is internally short-circuited, the drive device 222 drives the linkage assembly 221 to move. At this time, the linkage assembly 221 will not only cause the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11 and make the opening distance between the moving contact MC11 and the stationary contact SC11 the first opening distance, but also cause the moving contact MC12 in the contact assembly CT12 to separate from the stationary contact SC12 and make the opening distance between the moving contact MC12 and the stationary contact SC12 the first opening distance. For the specific process, please refer to the relevant description of the separation of the moving contact MC11 and the stationary contact SC11 and the opening distance between the moving contact MC11 and the stationary contact SC11 in the embodiments corresponding to Figures 2 to 9 above, which will not be repeated here.

[0065] When the inverter is a three-phase three-wire inverter and includes three relays, the inverter circuit 21 shown in Figure 2 can be replaced with the inverter circuit 21 shown in Figure 13. In this case, the inverter circuit 21 includes three AC output terminals, specifically L1 phase AC output terminal, L2 phase AC output terminal, and L3 phase AC output terminal. The relay K1 shown in Figure 2 can be replaced with relays K1, K3, and K4 shown in Figure 13. The L1 phase AC output terminal corresponds to relay K1, the L2 phase AC output terminal corresponds to relay K3, and the L3 phase AC output terminal corresponds to relay K4. Specifically, the L1 phase AC output terminal is connected to the output port OUT through the contact assembly CT11 in the corresponding relay K1, the L2 phase AC output terminal is connected to the output port OUT through the contact assembly CT3 in the corresponding relay K3, and the L3 phase AC output terminal is connected to the output port OUT through the contact assembly CT4 in the corresponding relay K4. The specific structures of relays K3 and K4 can be found in the description of the specific structure of relay K1 in the embodiments corresponding to Figures 2 to 9 above, and will not be repeated here. When the inverter 2 is internally short-circuited, the moving contact MC11 in the contact assembly CT11 separates from the stationary contact SC11, and the distance between the moving contact MC11 and the stationary contact SC11 is the first distance; the moving contact MC3 in the contact assembly CT3 separates from the stationary contact SC3, and the distance between the moving contact MC3 and the stationary contact SC3 is the first distance; the moving contact MC4 in the contact assembly CT4 separates from the stationary contact SC4, and the distance between the moving contact MC4 and the stationary contact SC4 is the first distance. The specific process can be found in the description of the separation of the moving contact MC11 from the stationary contact SC11 and the distance between the moving contact MC11 and the stationary contact SC11 being the first distance in the embodiments corresponding to Figures 2 to 9 above, and will not be repeated here.

[0066] When the inverter is a three-phase three-wire inverter and includes one relay, relays K1, K3, and K4 shown in Figure 13 can be replaced with relay K1 as shown in Figure 14. In this case, relay K1 includes three contact assemblies, specifically contact assembly CT11, contact assembly CT13, and contact assembly CT14. The L1 phase AC output terminal corresponds to contact assembly CT11, the L2 phase AC output terminal corresponds to contact assembly CT13, and the L3 phase AC output terminal corresponds to contact assembly CT14. Specifically, the L1 phase AC output terminal is connected to the output port OUT through the corresponding contact assembly CT11, the L2 phase AC output terminal is connected to the output port OUT through the corresponding contact assembly CT13, and the L3 phase AC output terminal is connected to the output port OUT through the corresponding contact assembly CT14. The moving contact MC11 in contact assembly CT11, the moving contact MC13 in contact assembly CT13, and the moving contact MC14 in contact assembly CT14 are all drive-connected to coil Y1. The moving contacts MC11, MC13, and MC14, and the drive device 222 are respectively drive-connected to the linkage assembly 221. When the inverter 2 is internally short-circuited, the drive device 222 drives the linkage assembly 221 to move. At this time, the linkage assembly 221 will not only cause the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11 and make the opening distance between the moving contact MC11 and the stationary contact SC11 the first opening distance, but also cause the moving contact MC13 in the contact assembly CT13 to separate from the stationary contact SC13 and make the opening distance between the moving contact MC13 and the stationary contact SC13 the first opening distance, and cause the moving contact MC14 in the contact assembly CT14 to separate from the stationary contact SC14 and make the opening distance between the moving contact MC14 and the stationary contact SC14 the first opening distance. For the specific process, please refer to the relevant description of the separation of the moving contact MC11 and the stationary contact SC11 and the opening distance between the moving contact MC11 and the stationary contact SC11 in the embodiments corresponding to Figures 2 to 9 above, which will not be repeated here.

[0067] When the inverter is a three-phase four-wire inverter and includes three relays, the inverter circuit 21 shown in Figure 13 can be replaced with the inverter circuit 21 shown in Figure 15. In this case, the inverter circuit 21 includes four AC output terminals, specifically L1 phase AC output terminal, L2 phase AC output terminal, L3 phase AC output terminal, and N-line AC output terminal. The L1 phase AC output terminal corresponds to relay K1, the L2 phase AC output terminal corresponds to relay K3, and the L3 phase AC output terminal corresponds to relay K4. The L1 phase AC output terminal is connected to the output port OUT through the contact assembly CT11 in the corresponding relay K1; the L2 phase AC output terminal is connected to the output port OUT through the contact assembly CT3 in the corresponding relay K3; the L3 phase AC output terminal is connected to the output port OUT through the contact assembly CT4 in the corresponding relay K4; and the N-line AC output terminal is connected to the output port OUT. When the inverter 2 is internally short-circuited, the specific operation of relays K1, K3, and K4 can be found in the embodiment corresponding to Figure 13 above, and will not be repeated here.

[0068] When the inverter is a three-phase four-wire inverter and includes a relay, relays K1, K3, and K4 shown in Figure 15 can be replaced with relay K5 shown in Figure 16. In this case, the L1-phase AC output terminal, L2-phase AC output terminal, and L3-phase AC output terminal are all connected to the output port out, and the N-line AC output terminal is connected to the output port out through the contact assembly CT5 in relay K5. The specific structure of relay K5 can be found in the description of the specific structure of relay K1 in the embodiments corresponding to Figures 2 to 9, and will not be repeated here. When the inverter 2 is internally short-circuited, the moving contact MC5 in the contact assembly CT5 separates from the stationary contact SC5, and the distance between the moving contact MC5 and the stationary contact SC5 is the first distance. The specific process can be found in the description of the separation of the moving contact MC11 from the stationary contact SC11 and the distance between the moving contact MC11 and the stationary contact SC11 being the first distance in the embodiments corresponding to Figures 2 to 9, and will not be repeated here.

[0069] When the inverter is a three-phase four-wire inverter and includes four relays, the specific structure can be as shown in Figure 17. The inverter 2 shown in Figure 15 also includes a relay K5 corresponding to the N-line AC output terminal. The N-line AC output terminal is connected to the output port out through the contact assembly CT5 in the corresponding relay K5. The specific structure of relay K5 can be found in the description of the specific structure of relay K1 in the embodiments corresponding to Figures 2 to 9 above, and will not be repeated here. When the inverter 2 is internally short-circuited, the moving contact MC11 in the contact assembly CT11 separates from the stationary contact SC11, and the distance between the moving contact MC11 and the stationary contact SC11 is the first distance. Similarly, the moving contact MC3 in the contact assembly CT3 separates from the stationary contact SC3, and the distance between the moving contact MC3 and the stationary contact SC3 is the first distance. Likewise, the moving contact MC4 in the contact assembly CT4 separates from the stationary contact SC4, and the distance between the moving contact MC4 and the stationary contact SC4 is the first distance. Finally, the moving contact MC5 in the contact assembly CT5 separates from the stationary contact SC5, and the distance between the moving contact MC5 and the stationary contact SC5 is the first distance. For details, please refer to the descriptions in the embodiments corresponding to Figures 2 to 9 above regarding the separation of the moving contact MC11 from the stationary contact SC11 and the setting of the distance between the moving contact MC11 and the stationary contact SC11 to the first distance. These details will not be repeated here.

[0070] When the inverter is a three-phase four-wire inverter and includes a relay, the inverter circuit 21 shown in Figure 14 can be replaced with the inverter circuit 21 shown in Figure 18. The inverter circuit 21 also includes a neutral (N) AC output terminal, which is connected to the output port out. When the inverter 2 is internally short-circuited, the specific operation of the relay K1 can be found in the embodiment corresponding to Figure 14 above, and will not be repeated here.

[0071] When the inverter is a three-phase four-wire inverter and includes one relay, relays K1, K3, K4, and K5 shown in Figure 17 can be replaced with relay K1 as shown in Figure 19. In this case, relay K1 includes four contact assemblies: CT11, CT13, CT14, and CT15. The L1 phase AC output corresponds to contact assembly CT11, the L2 phase AC output corresponds to contact assembly CT13, the L3 phase AC output corresponds to contact assembly CT14, and the N-line AC output corresponds to contact assembly CT15. Specifically, the L1 phase AC output is connected to the output port OUT via the corresponding contact assembly CT11, the L2 phase AC output is connected to the output port OUT via the corresponding contact assembly CT13, the L3 phase AC output is connected to the output port OUT via the corresponding contact assembly CT14, and the N-line AC output is connected to the output port OUT via the corresponding contact assembly CT15. The moving contact MC11 in contact assembly CT11, the moving contact MC13 in contact assembly CT13, the moving contact MC14 in contact assembly CT14, and the moving contact MC15 in contact assembly CT15 are all connected to coil Y1 via a transmission connection. The moving contacts MC11, MC13, MC14, and MC15, and the drive device 222 are also connected to the linkage assembly 221 via a transmission connection. When the inverter 2 is internally short-circuited, the drive device 222 drives the linkage assembly 221 to move. At this time, the linkage assembly 221 will not only cause the moving contact MC11 in the contact assembly CT11 to separate from the stationary contact SC11 and make the opening distance between the moving contact MC11 and the stationary contact SC11 the first opening distance, but also cause the moving contact MC13 in the contact assembly CT13 to separate from the stationary contact SC13 and make the opening distance between the moving contact MC13 and the stationary contact SC13 the first opening distance, and cause the moving contact MC14 in the contact assembly CT14 to separate from the stationary contact SC14 and make the opening distance between the moving contact MC14 and the stationary contact SC14 the first opening distance, and cause the moving contact MC15 in the contact assembly CT15 to separate from the stationary contact SC15 and make the opening distance between the moving contact MC15 and the stationary contact SC15 the first opening distance. For the specific process, please refer to the relevant description of the separation of the moving contact MC11 and the stationary contact SC11 and the making the opening distance between the moving contact MC11 and the stationary contact SC11 the first opening distance in the embodiments corresponding to Figures 2 to 9 above, which will not be repeated here.

[0072] As can be seen from Figures 2, 10 to 19 and their corresponding embodiments, when the inverter 2 includes at least two independent relays, even if the coil, linkage assembly, or drive device of one of the at least two relays fails, the other relays can still operate normally to interrupt the reverse current from the AC power grid 3, resulting in higher reliability of current interruption. When the inverter 2 includes one relay with at least two contact assemblies, the at least two contact assemblies share the same set of coil Y1, linkage assembly 221, and drive device 222, making the contact control method simpler and the cost lower. Furthermore, the embodiments of this application allow for flexible adjustment of the number of relays or the number of contact assemblies in a single relay according to the actual structure of the inverter 2, resulting in greater diversity in the circuit topology of the inverter 2.

[0073] When the inverter 2 further includes multiple DC-DC conversion circuits, the specific structure can be as shown in Figure 20. The inverter 2 shown in Figure 2 also includes DC-DC conversion circuits 26a, ..., and 26b. Each DC-DC conversion circuit 26a, ..., and 26b has two DC input terminals for connecting to each photovoltaic string in at least one photovoltaic string. For example, one DC input terminal in11 of DC-DC conversion circuit 26a is connected to the positive terminal of photovoltaic string 4a, and another DC input terminal in12 of DC-DC conversion circuit 26a is connected to the negative terminal of photovoltaic string 4a, ... Similarly, one DC input terminal inb1 of DC-DC conversion circuit 26b is connected to the positive terminals of photovoltaic strings 4b and 4c, and another DC input terminal inb2 of DC-DC conversion circuit 26b is connected to the negative terminals of photovoltaic strings 4b and 4c. The two DC output terminals of each DC-DC conversion circuit are connected to the two DC input terminals of inverter circuit 21. When inverter 2 receives DC power, each DC-DC converter is used to convert the DC power output from the photovoltaic string connected to it into electrical energy and output DC power to inverter circuit 21. Further, inverter circuit 21 is used to convert the DC power output from each DC-DC converter into AC power and output AC power to AC grid 3 when the moving contact MC11 and the stationary contact SC11 in the contact assembly CT11 are engaged.

[0074] It is understood that the inverter 2 shown in Figures 3 to 19 above may also include multiple DC-DC conversion circuits. The connection methods and functions of the multiple DC-DC conversion circuits can be found in the embodiment corresponding to Figure 20 above, and will not be repeated here.

[0075] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An inverter, characterized in that, The inverter includes an inverter circuit, at least one relay, and an output port. The inverter circuit includes at least two AC output terminals. Each relay includes a coil, a contact assembly, a linkage assembly, and a drive device. The contact assembly includes a stationary contact and a moving contact. At least one AC output terminal is connected to the output port through the contact assembly in at least one of the relays. The output port is used to connect to the AC power grid. The moving contact in the contact assembly is drivenly connected to the coil, and the moving contact in the contact assembly and the driving device are respectively drivenly connected to the connecting rod assembly; The drive device is used to drive the linkage assembly to move in the event of a short circuit inside the inverter, so that the linkage assembly causes the moving contact in the contact assembly to separate from the stationary contact and the opening distance between the moving contact and the stationary contact is a first opening distance; wherein, the first opening distance is greater than or equal to a second opening distance, the second opening distance being the opening distance between the moving contact and the stationary contact when the coil is de-energized and the moving contact in the contact assembly is driven to separate from the stationary contact in the inverter under normal conditions.

2. The inverter according to claim 1, characterized in that, The inverter also includes a controller; The controller is used to control the coil to be energized to drive the moving contact in the contact assembly to engage with the stationary contact when the inverter is operating normally, or to control the coil to be de-energized to drive the moving contact in the contact assembly to separate from the stationary contact to the second opening distance.

3. The inverter according to claim 2, characterized in that, The driving device is an electromagnetic device; The controller is also configured to output a drive signal to the electromagnetic device when a short circuit is detected inside the inverter; The electromagnetic device is used to drive the linkage assembly to move when the drive signal is received, so that the linkage assembly causes the moving contact in the contact assembly to separate from the stationary contact and make the opening distance between the moving contact and the stationary contact the first opening distance.

4. The inverter according to claim 1 or 2, characterized in that, The driving device is a magnetic tripping device; The magnetic tripping device is used to drive the linkage assembly to move when an internal short circuit is detected in the inverter, so that the linkage assembly causes the moving contact in the contact assembly to separate from the stationary contact and make the opening distance between the moving contact and the stationary contact the first opening distance.

5. The inverter according to any one of claims 1-4, characterized in that, Each of the relays also includes an arc-extinguishing device; The arc-extinguishing device is used to extinguish the electric arc generated when the moving contact and the stationary contact in the contact assembly separate.

6. The inverter according to any one of claims 1-5, characterized in that, The inverter includes at least two relays, each of the at least two relays includes a contact assembly, and at least a portion of the at least two AC output terminals correspond one-to-one with the at least two relays. Each of the at least some of the AC output terminals is connected to the output port via a contact assembly in a corresponding relay.

7. The inverter according to any one of claims 1-5, characterized in that, The inverter includes one of the relays, the relay includes at least two contact assemblies, and at least a portion of the at least two AC output terminals correspond one-to-one with the at least two contact assemblies; Each of the at least some of the AC output terminals is connected to the output port via a corresponding contact assembly.

8. The inverter according to any one of claims 1-7, characterized in that, The linkage assembly includes an elastic element and a linkage mechanism; The driving device is specifically used to drive the elastic element to release energy to push the linkage mechanism; The linkage mechanism is specifically used to drive the moving contact in the contact assembly to separate from the stationary contact under the push of the elastic element, and make the opening distance between the moving contact and the stationary contact the first opening distance.

9. The inverter according to any one of claims 1-7, characterized in that, The linkage assembly includes an elastic element, a linkage mechanism, and a switch. The driving device is specifically used to drive the elastic element to release energy to push the linkage mechanism; The linkage mechanism is specifically used to release the guillotine knife inserted between the moving contact and the stationary contact in the contact assembly under the push of the elastic member, so that the moving contact and the stationary contact in the contact assembly are separated and the opening distance between the moving contact and the stationary contact is the first opening distance.

10. The inverter according to claim 2 or 3, characterized in that, The inverter also includes a current detection device; The current detection device is used to detect the current flowing through the contact assembly; The controller is used to determine an internal short circuit in the inverter when the current flowing through the contact assembly is greater than or equal to a preset current value.

11. The inverter according to claim 10, characterized in that, The current detection device is connected between the inverter circuit and the moving contact in the contact assembly, or between the stationary contact in the contact assembly and the output port.

12. The inverter according to any one of claims 1-6, characterized in that, The inverter includes three relays, each of the three relays includes a contact assembly, and the inverter circuit includes four AC output terminals, three of the four AC output terminals corresponding one-to-one with the three relays; Each of the three AC output terminals is connected to the output port via a contact assembly in a corresponding relay.

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