Inverter

Abstract

The invention provides an inverter which comprises an input end, a direct current switch, a plurality of DC / DC converters, a direct current bus, a DC / AC converter, a controller and an output end, the direct current switch comprises an operating handle, an operating mechanism, a moving contact, a static contact and a first driving device, and the operating mechanism comprises a tripping component and a locking component. The input ends of the plurality of DC / DC converters are connected with the input end of the inverter through the DC switch. The controller sends a first driving signal to the first driving device when the inverter breaks down. When the first driving device receives the first driving signal, the first driving device drives a moving part in the first driving device so as to drive the locking part and the tripping part to be tripped and enable the moving contact to be separated from the static contact. And the operating handle cannot drive the moving contact to be in contact with or separated from the static contact under the condition that the tripping component and the locking component are tripped. Furthermore, the condition of fault diffusion caused by manual switching-on of the direct-current switch when the inverter fault still exists can be avoided.

Description

Technical Field

[0001] The present application relates to the field of power supply technology, and in particular to an inverter. Background Art

[0002] As the installed capacity of photovoltaic power generation continues to rise, photovoltaic inverters have become the mainstream power generation equipment in the photovoltaic industry. In order to ensure the stable operation of the power generation system where the photovoltaic inverter is located, the photovoltaic inverter needs to prevent its own fault from spreading when a fault occurs inside.

[0003] Currently, in Figure 1 When a fault occurs inside the photovoltaic inverter shown (such as a short circuit of the DC bus BUS+, BUS- or an internal power tube), the controller sends a voltage drive signal to the flux of the DC switch S1, so that the DC switch S1 is opened, and the connection line between the photovoltaic inverter and the photovoltaic string is disconnected, thereby achieving fault isolation.

[0004] For the above fault isolation scheme, after the DC switch S1 is successfully opened, even if the internal fault of the inverter is not eliminated, the maintenance personnel can still close the DC switch S1 again by operating the operating handle of the DC switch S1, thereby expanding the inverter fault. Summary of the invention

[0005] The present application provides an inverter, which can prevent a DC switch from being manually closed when an internal fault of the inverter still exists, thereby causing the fault to spread.

[0006] In the first aspect, the present application provides an inverter, which includes an input end, a DC switch, a plurality of DC / DC converters, a DC bus, a DC / AC converter, a controller and an output end, wherein the input end is used to connect a photovoltaic string, and the output end is used to connect an AC power grid. The DC switch includes an operating handle, an operating mechanism, a moving contact, a static contact, a first drive device and a second drive device. The input ends of the plurality of DC / DC converters are connected to the input end of the inverter through the DC switch, and the output ends of the plurality of DC / DC converters are connected in parallel to the DC bus. The input end of the DC / AC converter is connected to the DC bus, and the output end of the DC / AC converter is connected to the output end of the inverter. The operating mechanism includes a locking component, a tripping component, a transmission assembly and a reset component; the operating handle, the tripping component, the reset component and the moving contact are respectively connected to the transmission assembly in a transmission manner; the operating mechanism is used to drive the moving contact and the static contact to contact and separate, wherein, when the tripping component and the locking component are engaged, the operating handle can drive the transmission assembly to drive the moving contact and the static contact to contact and separate; when the tripping component and the locking component are disengaged, the operating handle cannot drive the transmission assembly to drive the moving contact and the static contact to contact and separate. The controller is used to send a first drive signal to the first drive device when the inverter fails. The first drive device is used to drive the moving component in the first drive device to move when receiving the first drive signal, so as to drive the locking component and the tripping component to disengage, so that the transmission assembly drives the moving contact and the static contact to separate. After the first drive device drives the moving contact and the static contact to separate, the operating handle is used to be unable to drive the moving component in the first drive device to reset when subjected to external force. The controller is also used to send a second drive signal to the second drive device when a photovoltaic string or its connecting line fails. The second driving device is used to drive the moving part in the second driving device to move when receiving the second driving signal, so as to drive the locking part and the tripping part to disengage, so that the transmission assembly drives the moving contact to separate from the static contact. After the second driving device drives the moving contact to separate from the static contact, the operating handle is also used to drive the transmission assembly to drive the reset part to move when subjected to external force, so as to reset the moving part in the second driving device. After the moving part in the second driving device is reset, the operating handle is also used to drive the tripping part and the locking part to engage when subjected to external force, so that the operating handle can drive the transmission assembly to drive the moving contact to contact the static contact.

[0007] In this embodiment, in the case of a fault in the inverter, since the DC switch is opened, the operating handle cannot drive the movable part in the first drive device to reset when subjected to external force, thus avoiding the situation where the DC switch is manually closed when the internal fault of the inverter still exists, causing the fault to spread. In addition, in the case of a fault in the photovoltaic string or its connecting line, since the DC switch is opened, the operating handle can drive the DC switch to close when subjected to external force, thus meeting the debugging needs of maintenance personnel when troubleshooting the fault in the photovoltaic string or its connecting line.

[0008] In combination with the first aspect, in a first possible implementation, the controller is specifically used to: in the event of a failure in the photovoltaic string or its connecting line, if the number of second drive signals sent to the second drive device does not exceed a preset threshold, send the second drive signal to the second drive device; the controller is also used to: in the event of a failure in the photovoltaic string or its connecting line, if the number of second drive signals sent to the second drive device exceeds a preset threshold, send the first drive signal to the first drive device.

[0009] In this embodiment, after the DC switch is opened due to a fault in the photovoltaic string or its connecting line, the DC switch can be manually closed within a preset number of times, thereby not only meeting the debugging needs of maintenance personnel when troubleshooting the photovoltaic string or its connecting line fault, but also effectively avoiding the spread of the fault.

[0010] In combination with the first aspect or the first possible implementation of the first aspect, in a second possible implementation, the controller is further used to send a third drive signal to the first drive device when the inverter fault is eliminated. The first drive device is also used to drive the moving parts in the first drive device to reset when receiving the third drive signal. After the moving parts in the first drive device are reset, the operating handle drives the tripping part to engage with the locking part when subjected to an external force, so that the operating handle can drive the transmission assembly to drive the moving contact to contact the static contact.

[0011] In this embodiment, the inverter controls the reset of the moving parts in the first drive device when its own fault is eliminated, thereby ensuring that the DC switch can be manually closed after the inverter fault is eliminated to meet the maintenance or debugging needs of the maintenance personnel for the inverter.

[0012] In combination with any one of the first aspect to the second possible implementation manner of the first aspect, in a third possible implementation manner, the controller is also used to determine that an inverter fault has occurred when the electrical parameters of the inverter exceed a first preset parameter range, wherein the electrical parameters of the inverter include a bus voltage value or a bus current value of the DC bus.

[0013] In this implementation, the inverter can determine whether a fault occurs to itself based on the bus voltage value or the bus current value, and the fault detection method is diverse and highly flexible.

[0014] In combination with any one of the first aspect to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the controller is also used to determine that a fault has occurred in the photovoltaic string or a connecting line thereof when the electrical parameters of the photovoltaic string exceed a second preset parameter range, wherein the electrical parameters of the photovoltaic string include an output voltage value, an output current value, or an insulation resistance value to ground.

[0015] In this embodiment, the inverter can determine whether the photovoltaic string or its connecting line is faulty based on the output voltage value, output current value or insulation resistance value of the photovoltaic string. The fault detection method is diverse and highly flexible.

[0016] In the second aspect, the present application provides an inverter, which includes an input end, a DC switch, a plurality of DC / DC converters, a DC bus, a DC / AC converter, a controller and an output end, wherein the input end is used to connect a photovoltaic string, and the output end is used to connect an AC power grid, and the DC switch includes an operating handle, an operating mechanism, a moving contact, a static contact and a first drive device. Among them, the input ends of the plurality of DC / DC converters are connected to the input end of the inverter through the DC switch, and the output ends of the plurality of DC / DC converters are connected in parallel to the DC bus. The input end of the DC / AC converter is connected to the DC bus, and the output end of the DC / AC converter is connected to the output end of the inverter. The operating mechanism includes a locking component, a tripping component, a transmission assembly and a reset component; the operating handle, the tripping component, the reset component and the moving contact are respectively connected to the transmission assembly in a transmission manner; the operating mechanism is used to drive the moving contact and the static contact to contact and separate, wherein when the tripping component and the locking component are engaged, the operating handle can drive the transmission assembly to drive the moving contact and the static contact to contact and separate; when the tripping component and the locking component are disengaged, the operating handle cannot drive the transmission assembly to drive the moving contact and the static contact to contact and separate. The controller is used to send a first drive signal to the first drive device when a fault occurs in the inverter, the photovoltaic string or the connection line of the photovoltaic string. The first drive device is used to drive the moving parts in the first drive device to move when receiving the first drive signal, so as to drive the locking part and the tripping part to disengage, and enable the transmission component to drive the moving contact and the static contact to separate; the controller is also used to send a third drive signal to the first drive device when the inverter fault is eliminated; and before the fault of the photovoltaic string or its connecting line is eliminated and the moving contact and the static contact are separated, send the third drive signal to the first drive device; the first drive device is also used to drive the moving parts in the first drive device to reset when receiving the third drive signal; after the moving parts in the first drive device are reset, the operating handle is also used to drive the tripping part and the locking part to engage when subjected to external force, so that the operating handle can drive the transmission component to drive the moving contact to contact the static contact.

[0017] In this embodiment, in the case of a fault in the inverter, since the DC switch is opened, the operating handle cannot drive the movable parts in the first drive device to reset when subjected to external force, thus avoiding the situation where the DC switch is manually closed when the internal fault of the inverter still exists, causing the fault to spread. In addition, in the case of a fault in the photovoltaic string or its connecting line, after the DC switch is opened, the inverter immediately controls the movable parts in the first drive device to reset, and then the operating handle can drive the DC switch to close when subjected to external force, thus meeting the debugging needs of maintenance personnel when troubleshooting the photovoltaic string or its connecting line. In addition, the inverter controls the movable parts in the first drive device to reset when its own fault is eliminated, thereby ensuring that the DC switch can be manually closed after the inverter fault is eliminated.

[0018] In combination with the second aspect, in a first possible implementation manner, the controller is specifically used to: before the fault of the photovoltaic string or its connecting line is eliminated and the moving contact is separated from the static contact, if the number of third drive signals sent to the first drive device does not exceed a preset threshold, then send the third drive signal to the first drive device; the controller is also used to: when a fault occurs in the photovoltaic string or its connecting line, if the number of third drive signals sent to the second drive device exceeds a preset threshold, stop sending the third drive signal to the first drive device.

[0019] In this embodiment, after the DC switch is opened due to a fault in the photovoltaic string or its connecting line, the DC switch can be manually closed within a preset number of times, thereby not only meeting the debugging needs of maintenance personnel when troubleshooting the photovoltaic string or its connecting line fault, but also effectively avoiding the spread of the fault.

[0020] In combination with any one of the second possible implementations of the second aspect to the second aspect, in a fourth possible implementation, the controller is also used to determine that an inverter fault has occurred when the electrical parameters of the inverter exceed a first preset parameter range, wherein the electrical parameters of the inverter include a bus voltage value or a bus current value of the DC bus.

[0021] In this implementation, the inverter can determine whether a fault occurs to itself based on the bus voltage value or the bus current value, and the fault detection method is diverse and highly flexible.

[0022] In combination with any one of the second aspect to the third possible implementation manners of the second aspect, in a fifth possible implementation manner, the controller is also used to determine that a fault has occurred in the photovoltaic string or a connecting line thereof when the electrical parameters of the photovoltaic string exceed a second preset parameter range, wherein the electrical parameters of the photovoltaic string include an output voltage value, an output current value, or an insulation resistance value to ground.

[0023] In this embodiment, the inverter can determine whether the photovoltaic string or its connecting line is faulty based on the output voltage value, output current value or insulation resistance value of the photovoltaic string. The fault detection method is diverse and highly flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a photovoltaic inverter provided by the prior art;

[0025] Figure 2 It is a schematic diagram of the application scenario of the inverter provided in this application;

[0026] Figure 3 It is a structural schematic diagram of the inverter provided by the present application;

[0027] Figure 4 is a schematic diagram of a DC switch provided by the present application;

[0028] Figure 5 is another schematic diagram of the DC switch provided by the present application;

[0029] Figure 6 is another schematic diagram of the DC switch provided by the present application;

[0030] Figure 7 is another schematic diagram of the DC switch provided by the present application;

[0031] Figure 8 is another schematic diagram of the DC switch provided by the present application;

[0032] Fig. 9 is another schematic diagram of the DC switch provided by the present application;

[0033] Fig.10 is another structural schematic diagram of the inverter provided by the present application;

[0034] Fig.11 is another schematic diagram of the DC switch provided by the present application;

[0035] Fig.12 is another schematic diagram of the DC switch provided by the present application;

[0036] Fig.13 is another schematic diagram of the DC switch provided by the present application;

[0037] Fig.14 This is another schematic diagram of the DC switch provided in this application. DETAILED DESCRIPTION

[0038] The inverter provided in this application can be applied to various application fields such as photovoltaic power generation, photovoltaic storage hybrid power generation, new energy smart microgrid, power transmission and distribution, etc. The inverter provided in this application can be applied to different application scenarios, such as photovoltaic power supply scenario, photovoltaic storage hybrid power supply scenario, UPS power supply scenario, etc. The photovoltaic power supply scenario is used as an example for explanation.

[0039] See also Figure 2 , Figure 2 Schematic diagram of the application scenario of the inverter provided in this application. Figure 2As shown, the inverter 1 includes an input end, a DC switch S1, a DC / DC converter 111, ..., a DC / DC converter 11n, a DC bus (including a positive DC bus BUS+ and a negative DC bus BUS-), a DC / AC converter 12, a controller 13 and an output end. Among them, the DC switch S1 includes an operating handle, an operating mechanism, a moving contact, a static contact, a first drive device and a second drive device, and the operating mechanism includes a tripping component and a locking component, and n is an integer greater than 1. The operating mechanism includes a locking component, a tripping component, a transmission assembly and a reset component; the operating handle, the tripping component, the reset component and the moving contact are respectively connected to the transmission assembly. The operating mechanism is used to drive the moving contact and the static contact to contact and separate, wherein, when the tripping component and the locking component are engaged, the operating handle can drive the transmission assembly to drive the moving contact and the static contact to contact and separate; when the tripping component and the locking component are disengaged, the operating handle cannot drive the transmission assembly to drive the moving contact and the static contact to contact and separate.

[0040] The input end of the inverter 1 is connected to a photovoltaic string (at least one photovoltaic component is connected in series and in parallel), and the output end of the inverter 1 is connected to an AC power grid or a load (such as a household appliance). The input end of the DC / DC converter 111, ..., and the input end of the DC / DC converter 11n are connected to the input end of the inverter 1 through a DC switch S1, and the output end of the DC / DC converter 111, ..., and the output end of the DC / DC converter 11n are connected in parallel and are respectively connected to the positive DC bus BUS+ and the negative DC bus BUS-. The input end of the DC / AC converter 12 is respectively connected to the positive DC bus BUS+ and the negative DC bus BUS-, and the output end of the DC / AC converter 12 is connected to the output end of the inverter 1.

[0041] After the inverter 1 starts to operate, that is, after the DC switch S1 is closed, the controller 13 adjusts the output voltage of the photovoltaic strings connected to each DC / DC converter by controlling each of the n DC / DC converters to perform maximum power point tracking (MPPT) on the output power of the photovoltaic strings, so that the output power of the photovoltaic strings connected to each DC / DC converter is maximized. At the same time, the controller 13 also controls each DC / DC converter to perform DC conversion on the output voltage of the photovoltaic strings connected to each of them, and outputs the DC voltage after DC conversion to the DC bus. The controller 13 also controls the DC / AC converter 12 to invert the DC bus voltage at its input end into AC power, thereby realizing power supply to various types of electrical equipment such as AC power grids or loads.

[0042] The embodiments of the present application are mainly aimed at optimizing the operation of the DC switch S1 in a fault scenario in the above implementation scenario.

[0043] Specifically, the embodiment of the present application divides the fault scenarios into two categories. One is the fault of the internal components or circuits of the inverter 1. Such faults need to be eliminated by professionals. Otherwise, closing the DC switch S1 before the fault is eliminated will cause the fault to expand further. The other is the external fault on the DC side of the inverter 1, which is mainly the fault of the photovoltaic string or its connecting line. Such faults are generally caused by manual reverse connection of the photovoltaic components. Therefore, after manual elimination, the DC switch S1 can be manually closed to start the normal operation of the inverter.

[0044] Based on the above fault classification and fault solving ideas, an inverter is designed in the embodiment of the present application, and its controller 13 can classify the above two fault types, and at the same time improve the internal structure of the DC switch S1, so that the DC switch S1 can achieve different effects under different fault types through the control of the controller 13.

[0045] Specifically, after the inverter 1 starts running, if a fault is detected inside the inverter 1, the controller 13 sends a first drive signal to the first drive device. When the first drive device receives the first drive signal, it drives the moving part in the first drive device to move, so as to drive the locking part and the tripping part to be disengaged, so that the moving contact and the static contact of the DC switch S1 are separated, so as to disconnect the connection between the inverter 1 and the photovoltaic string, and realize fault isolation. In the embodiment of the present application, in the case of a fault inside the inverter 1, after the first drive device drives the moving contact and the static contact of the DC switch S1 to separate, because the moving part continues to apply force to the locking part, the operating handle cannot drive the moving part in the first drive device to reset when subjected to external force, so that the tripping part and the locking part cannot be engaged, and then the operating handle cannot drive the DC switch S1 to close.

[0046] If a fault is detected in the photovoltaic string or its connection line (fault on the external DC side of the inverter), the controller 13 sends a second drive signal to the second drive device. When the second drive device receives the second drive signal, it drives the moving part in the second drive device to move, so as to drive the locking part and the tripping part to be released, so as to separate the moving contact and the static contact of the DC switch S1, so as to disconnect the connection between the inverter 1 and the photovoltaic string, and realize fault isolation. In the embodiment of the present application, in the case of a fault in the photovoltaic string or its connection line, after the second drive device drives the moving contact and the static contact of the DC switch S1 to be separated, by setting a reset part for the second drive device in the DC switch S1, the operating handle can be reset by the reset part when subjected to external force, and then the operating handle can further drive the tripping part to engage with the tripping part, and drive the moving contact of the DC switch S1 to contact the static contact, so as to close the DC switch S1.

[0047] It is understandable that in the case of a fault in the inverter 1, after the DC switch S1 is opened, the operating handle cannot drive the movable parts in the first drive device to reset under the condition of external force, and then the locking part and the tripping part are disconnected and continue to maintain the tripped state. Therefore, it can be avoided that the DC switch S1 is manually closed when the internal fault of the inverter 1 still exists, causing the fault to spread. In addition, in the case of a fault in the photovoltaic string or its connecting line, since there is a reset component for the second drive device, after the DC switch is opened, the operating handle can reset the movable parts of the second drive device through the reset component under the condition of external force, and then the tripping part can be driven to engage with the tripping part and the DC switch S1 can be closed. Therefore, it can meet the debugging needs of maintenance personnel when troubleshooting photovoltaic strings or their connecting lines.

[0048] The above is only an example of the application scenarios of the inverter provided in this application, and is not an exhaustive list. This application does not limit the application scenarios.

[0049] Combine the following Figures 3 to 14 The working principle of the inverter provided in this application is illustrated by way of example.

[0050] See also Figure 3 , Figure 3 Schematic diagram of the structure of the inverter provided by this application. Figure 3 As shown, the inverter 1 includes input terminals (including input terminals i 11+, i 11-, i 12+, i 12-, ..., input terminals i 1n1+, i 1n1-, i 1n2+, and input terminals i 1n2-), DC switches S1, DC / DC converters 111, ..., DC / DC converters 11n, DC buses (including positive DC bus BUS+ and negative DC bus BUS-), DC / AC converters 12, controllers 13, and output terminals (including output terminals o11 and o12). The DC switch S1 includes an operating handle, an operating mechanism, a moving contact, a static contact, a first drive device, and a second drive device. The operating mechanism includes a tripping component and a locking component. n is an integer greater than 1. The input terminal of the inverter 1 is used to connect to a photovoltaic string, and the output terminals o11 and o12 of the inverter 1 are used to connect to an AC power grid. The input ends of the n DC / DC converters are connected to the input end of the inverter 1 through the DC switch S1, and the output ends of the n DC / DC converters are connected in parallel to the positive DC bus BUS+ and the negative DC bus BUS-. The input ends of the DC / AC converter 12 are connected to the positive DC bus BUS+ and the negative DC bus BUS-, and the output ends of the DC / AC converter 12 are connected to the output end o11 and the output end o12 of the inverter 1.

[0051] In one implementation scenario, during the process of the inverter 1 supplying power to the AC power grid, in the event of a fault in the inverter 1, the controller 13 sends a first drive signal to the first drive device. When the first drive device receives the first drive signal, it drives the moving part in the first drive device to drive the locking part and the tripping part to disengage, thereby separating the moving contact and the static contact of the DC switch S1, that is, opening the DC switch S1. After the DC switch S1 is opened, the operating handle cannot drive the moving part in the first drive device to reset when subjected to external force, thereby failing to drive the tripping part and the locking part to engage, and further failing to drive the moving contact and the static contact of the DC switch S1 to contact.

[0052] In a possible implementation, when it is detected that the fault of the inverter 1 is eliminated, the controller 13 may send a third drive signal to the first drive device. When the first drive device receives the third drive signal, it drives the moving parts in the first drive device to reset. After the moving parts in the first drive device are reset, the operating handle drives the tripping part to engage with the locking part under the condition of external force, and drives the moving contact of the DC switch S1 to contact with the static contact.

[0053] Among them, the first drive device can be a control device that can realize the reciprocating motion of the moving part between two positions, such as a release, a motor, etc. Exemplarily, the first drive device is a bistable release, and the moving part in the first drive device is a part that can be driven by a magnetic field to move between two stable positions. The second drive device can be a control device that can realize the movement of the moving part to at least one position, such as a release, a motor, etc. Exemplarily, the first drive device is a release, and the moving part in the first drive device is a moving part. Of course, the second drive device can also be a bistable release.

[0054] For ease of understanding, the following takes the first drive device and the second drive device as an example, both of which are releasers. Figures 4 to 7 The schematic diagram of the DC switch S1 is shown as an example. Figures 4 to 7, the DC switch S1 includes an operating handle Lf, a moving contact K1, a stationary contact K2, a release TX1, a release TX2 and an operating mechanism, the operating mechanism includes a transmission assembly, a locking component, a tripping component and a reset component, wherein, exemplarily, the transmission assembly may include a connecting rod structure OA, a connecting rod structure AB, a connecting rod structure BC, a connecting rod structure GJ, a connecting rod structure GE and an elastic member GB, the reset component is EKF, the tripping component is DCH, and the locking component is M. Among them, the connecting rod structure OA, the connecting rod structure AB and the connecting rod structure BC constitute a linkage structure OABC, the connecting rod structure GJ and the connecting rod structure GE constitute a linkage structure GJE, and O, D, f, J, K and Y all represent fixed hinges. d1 represents the moving component in the release TX1, and d2 represents the moving component in the release TX2. The connecting rod structure EK and the connecting rod structure KF in the reset component EKF are in a rigid coupling relationship, and the connecting rod structure EK and the connecting rod structure KF rotate synchronously around point K.

[0055] It should be noted that, in the embodiment of the present application, the reset component EKF has a transmission relationship only with the second drive device (tripper TX2), and has no transmission relationship with the first drive device (tripper TX1). That is to say, the moving component d2 of the tripper TX2 can be reset by controlling the reset accessory EKF, but the moving component d1 of the tripper TX1 cannot be reset.

[0056] When the inverter 1 supplies power to the AC grid, the DC switch S1 is in the closed state, corresponding to Figure 4 The switch status shown. Figure 4 As shown, the locking component M is engaged with the tripping component DCH, the moving contact K1 and the stationary contact K2 are in contact, the current position of the moving component d1 is x1 (first position), and the current position of the moving component d2 is x1' (third position). The controller 13 determines that the inverter 1 has a fault based on the electrical parameters of the inverter 1 exceeding the first preset parameter range, wherein the electrical parameters of the inverter 1 include the bus voltage value or the bus current value of the DC bus.

[0057] Exemplarily, the electrical parameter of the inverter 1 is the bus voltage value of the DC bus, and the first preset parameter range is greater than the first voltage value. When the bus voltage value of the DC bus is less than or equal to the first voltage value, the controller 13 indicates that the DC bus is short-circuited, and determines that the inverter 1 is faulty.

[0058] Exemplarily, the electrical parameter of the inverter 1 is the bus current value of the DC bus, and the first preset parameter range is less than the first current value. When the bus current value of the DC bus is greater than or equal to the first current value, the controller 13 indicates that the DC bus is short-circuited, and determines that the inverter 1 is faulty.

[0059] In the event of a fault in the inverter 1, the controller 13 sends a first drive signal (such as a positive pulse) to the release TX1. Figure 5 As shown, when the release TX1 receives the first drive signal, it drives the moving part d1 to move from position x1 to position x2 (second position), that is, Figure 5 The position of the middle moving part d1 drives the lock part M to rotate clockwise around point Y, and the lock part M is released from the tripping part DCH, causing the tripping part DCH to rotate counterclockwise. Driven by the elastic potential energy stored in the elastic part GB, point B moves to the right, causing the moving contact K1 to rotate rapidly clockwise under the pull of the connecting rod mechanism AB, thereby separating the moving contact K1 and the static contact K2, and the DC switch S1 is opened. Since the operating mechanism of the DC switch S1 does not include a reset component for the moving component d1 of the release TX1, the reset component EKF only serves as a reset component for the moving component d2 of the release TX2. Therefore, after the DC switch S1 is opened, even if the maintenance personnel manually push the operating handle Lf to rotate clockwise, driving point E to rotate clockwise, and then driving the connecting rod structure KF to rotate clockwise to perform the moving component reset operation, it is impossible to drive the moving component d1 to reset (i.e., drive the moving component d1 back from position x2 to position x1) by operating the operating handle of the DC switch S1. The moving component d1 will always be at position x2, resulting in the inability to engage the tripping component DCH with the locking component M by operating the operating handle of the DC switch S1, and further the inability to close the DC switch S1 by operating the operating handle of the DC switch S1.

[0060] In the above case, after the DC switch S1 is opened, professional personnel are required to perform maintenance. After the maintenance, the controller 13 can detect the electrical parameters of the inverter 1, and when the electrical parameters of the inverter 1 are within the first preset parameter range, it indicates that the fault of the inverter 1 has been eliminated, and the controller 13 sends a third drive signal (such as a reverse pulse) to the release TX1. When the release TX1 receives the third drive signal, it drives the moving part d1 to move from position x2 to position x1 to achieve the reset of the moving part d1. The locking part M rotates counterclockwise due to the reset of the moving part d1 and stops at Figure 6 As the movable part d1 has been reset, the maintenance personnel can push the operating handle Lf to rotate clockwise, and the operating handle Lf will push the tripping part DCH to rotate clockwise, and the locking part M will be locked by the tripping part DCH, that is, the locking part M is locked with the tripping part DCH, corresponding to Figure 7After that, the maintenance personnel pushes the operating handle Lf to rotate counterclockwise, so that the tension direction of the elastic member GB exceeds the left side of the connecting rod structure BC. Point B moves to the left under the tension of the elastic member GB, and the connecting rod structure AB pushes the moving contact K1 downward to close, so that the moving contact K1 and the static contact K2 are in a closed state, corresponding to Figure 4 In the switching state shown, the DC switch S1 is closed.

[0061] It is understandable that, in the case of a fault in the inverter 1, the controller 13 controls the DC switch S1 to open by driving the moving parts in the first drive device. Since the DC switch S1 is not provided with a reset part for the moving parts in the first drive device, the maintenance personnel cannot close the DC switch S1 by operating the operating handle of the DC switch S1. Only when the controller 13 detects that the fault of the inverter 1 has been eliminated, the controller 13 controls the reset of the moving parts in the first drive device, and then the maintenance personnel can close the DC switch S1 by operating the operating handle of the DC switch S1. Furthermore, it can be ensured that when the inverter 1 fails, the maintenance personnel cannot close the DC switch S1 by operating the operating handle of the DC switch S1 before the fault is eliminated. After professional maintenance is required, the inverter internal controller 13 can further close the switch after detection and confirmation, thereby ensuring the safety of the maintenance personnel.

[0062] In another implementation scenario, during the process of the inverter 1 supplying power to the AC power grid, when a photovoltaic string or its connecting line fails (external fault of the inverter), the controller 13 sends a second drive signal to the second drive device. When the second drive device receives the second drive signal, it drives the moving part in the second drive device to drive the locking part and the tripping part to be released, so that the moving contact and the static contact of the DC switch S1 are separated, that is, the DC switch S1 is opened. After the DC switch S1 is opened, the operating handle drives the moving part in the second drive device to reset through the reset part under the condition of external force, drives the tripping part and the locking part to engage, and drives the moving contact of the DC switch S1 to contact the static contact. Among them, the second drive device can be a device capable of realizing unidirectional motion control, such as a release, a motor, etc.

[0063] For ease of understanding, the following again takes the first drive device and the second drive device as an example, both of which are releasers. Figure 4 , Figures 8 to 9 The schematic diagram of the DC switch S1 is shown for example.

[0064] When the inverter 1 supplies power to the AC grid, the DC switch S1 is in the closed state, corresponding to Figure 4 The switch status shown. Figure 4As shown, the current position of the moving component d1 is x1, and the current position of the moving component d2 is x1'. The controller 13 determines that the photovoltaic string or its connecting line has a fault based on the electrical parameters of the photovoltaic string exceeding the second preset parameter range, wherein the electrical parameters of the photovoltaic string include the output voltage value, output current value or insulation resistance value of the photovoltaic string to the ground.

[0065] Exemplarily, the electrical parameter of the photovoltaic string is the reverse output current value, and the second preset parameter range is less than or equal to the second current value. When the reverse output current value of the photovoltaic string is greater than the second current value, the controller 13 indicates that the photovoltaic string connected to the input end of the inverter 1 is reversely connected or short-circuited, and determines that the photovoltaic string or its connecting line has a fault. Among them, the second current value can be determined according to actual conditions, and this application does not make specific restrictions on this. Preferably, in order to detect the fault as early as possible and trigger the protection action of the DC switch S1 in time, the second current value can be a smaller value, such as 0.

[0066] Exemplarily, the electrical parameter of the photovoltaic string is an output voltage value, and the second preset parameter range is greater than the second voltage value. When the output voltage value of the photovoltaic string is less than or equal to the second voltage value, the controller 13 indicates that there is a short circuit in the photovoltaic string or its connecting line connected to the input end of the inverter 1, and determines that there is a fault in the photovoltaic string or its connecting line.

[0067] Exemplarily, the electrical parameter of the photovoltaic string is the insulation resistance value to ground, and the second preset parameter range is the safe range of the insulation resistance value to ground when there is no electrical connection between the electrical equipment or line and the ground. When the insulation resistance value to ground of the photovoltaic string exceeds the second preset parameter range, the controller 13 indicates that the connection line of the photovoltaic string is insulated and grounded, and determines that the photovoltaic string or its connection line has a fault.

[0068] Afterwards, in the event of a failure of the photovoltaic string or its connecting line, the controller 13 sends a second drive signal to the trip unit TX2. Figure 8 As shown, when the release TX2 receives the second drive signal, it drives the moving part d2 to move from the position x1' to the position x2' (the fourth position), that is, Figure 8 The position of the middle moving part d2 is driven to drive the lock part M to rotate clockwise around point Y, and the lock part M is released from the tripping part DCH, causing the tripping part DCH to rotate counterclockwise. Driven by the elastic potential energy stored in the elastic part GB, point B moves to the right, causing the moving contact K1 to rotate rapidly clockwise under the pull of the connecting rod mechanism AB, thereby separating the moving contact K1 and the static contact K2, and the DC switch S1 is opened.

[0069] Since the DC switch S1 is provided with a reset component for the moving part d2, after the DC switch S1 is opened, the maintenance personnel can manually push the operating handle Lf clockwise based on the debugging requirements (for example, the maintenance personnel believe that the fault of the photovoltaic string or its connecting line has been eliminated), drive the point E clockwise, and then drive the connecting rod structure KF clockwise to drive the moving part d2 from position x2' back to position x1', so as to reset the moving part d2. The locking part M rotates counterclockwise due to the reset of the moving part d2 and stops at Fig. 9 After the moving part d2 is reset, the maintenance personnel can continue to push the operating handle Lf to rotate clockwise, and the operating handle Lf pushes the tripping part DCH to rotate clockwise, and the locking part M is buckled by the tripping part DCH, that is, the locking part M is buckled with the tripping part DCH, corresponding to Figure 7 After that, the maintenance personnel pushes the operating handle Lf to rotate counterclockwise, so that the tension direction of the elastic member GB exceeds the left side of the connecting rod structure BC. Point B moves to the left under the tension of the elastic member GB, and the connecting rod structure AB pushes the moving contact K1 downward to close, so that the moving contact K1 and the static contact K2 are in a closed state, corresponding to Figure 4 In the switching state shown, the DC switch S1 is closed.

[0070] Furthermore, in order to meet the debugging requirements of the maintenance personnel that the DC switch can be manually closed when the fault of the photovoltaic string and its connecting line is eliminated, and at the same time to avoid the situation where the user directly closes the DC switch S1 multiple times when the fault of the photovoltaic string and its connecting line is not eliminated, the controller 13 starts to count the number of times the second drive signal is sent to the release TX2 after the photovoltaic string or its connecting line fails. If the number of times the second drive signal is sent does not exceed the preset threshold, then if the maintenance personnel detects that the photovoltaic string or its connecting line is still faulty after manual closing, the second drive signal will continue to be sent to open the DC switch S1, and manual closing can be performed manually; if the number of times the second drive signal is sent is greater than the preset threshold, the second drive signal will stop being sent to the release TX2, and the first drive signal will be sent to the release TX1, so that the DC switch S1 is opened and cannot be closed manually, corresponding to Figure 5 The switch state shown. For details, please refer to the control principle of the first drive signal above. Among them, the preset threshold is determined based on the number of times the DC switch can be safely disconnected and a margin is reserved. For example, the preset threshold is 3. In this way, it can be ensured that in the event of a fault in the photovoltaic string or its connecting line, a certain number of manual closings are allowed to meet the debugging requirements, and it can also avoid the maintenance personnel from closing the switch multiple times without eliminating the fault, which may cause the fault to spread.

[0071] In the embodiment of the present application, the DC switch S1 is provided with a first drive device that is only controlled by the controller 13 to realize the resetting of the moving parts and a second drive device that can reset the moving parts by an operating handle. When the inverter 1 fails, the controller 13 controls the first drive device to open the DC switch S1. When the photovoltaic string or its connecting line fails, the controller 13 controls the second drive device to open the DC switch S1. In this way, when the inverter 1 fails, the DC switch S1 cannot be manually closed. When the photovoltaic string or its connecting line fails, the DC switch S1 can be manually closed within a preset number of times, thereby effectively avoiding the spread of the fault.

[0072] See also Fig.10 , Fig.10 is another structural schematic diagram of the inverter provided by the present application. Fig.10 As shown, the DC switch S1 includes an operating handle, an operating mechanism, a moving contact, a stationary contact and a first drive device, and the operating mechanism includes a tripping component and a locking component. For a description of other circuits in the inverter 1 except the DC switch S1 and their connection relationships, please refer to Figure 3 The description of the corresponding parts in the inverter 1 shown is not repeated here.

[0073] The main difference from the above embodiment is that Fig.10 In the illustrated embodiment, the inverter has only one first drive device but no second drive device. The controller 13 controls the first drive device to complete the functions of the first drive device and the second drive device in the above embodiment.

[0074] In one implementation scenario, during the process of the inverter 1 supplying power to the AC power grid, when a fault occurs inside the inverter 1, the controller 13 sends a first drive signal to the first drive device. When the first drive device receives the first drive signal, it drives the moving part in the first drive device to drive the locking part and the tripping part to trip, so that the moving contact and the static contact of the DC switch S1 are separated, that is, the DC switch S1 is opened. After the DC switch S1 is opened, the operating handle cannot drive the moving part in the first drive device to reset under the condition of external force, so that the tripping part and the locking part cannot be driven to engage, and then the moving contact and the static contact of the DC switch S1 cannot be driven to contact. Afterwards, when the fault of the inverter 1 is eliminated, the controller 13 sends a third drive signal to the first drive device. When the first drive device receives the third drive signal, it drives the moving part in the first drive device to reset. After the moving part in the first drive device is reset, the operating handle drives the tripping part and the locking part to engage under the condition of external force, and drives the moving contact and the static contact of the DC switch S1 to contact.

[0075] For ease of understanding, the following takes the first driving device as the tripper TX1 as an example. Figures 11 to 14 The schematic diagram of the DC switch S1 is shown for example. Figures 11 to 14 The DC switch S1 shown is Figures 4 to 9 Compared with the DC switch S1 shown in FIG. 1 , the connecting rod structure GJ, the connecting rod structure GE, the reset component EKF and the release TX2 are no longer included. Here, Figures 11 to 14 For a description of the structural parts of the DC switch S1 shown, see Figures 4 to 9 The description of the corresponding parts of the DC switch S1 shown is not repeated here.

[0076] When the inverter 1 supplies power to the AC grid, the DC switch S1 is in the closed state, corresponding to Fig.11 The switch status shown. Fig.11 As shown, the locking component M is engaged with the tripping component DCH, the moving contact K1 and the stationary contact K2 are in a closed state, and the current position of the moving component d1 is x1. When the controller 13 determines that the inverter 1 fails based on the electrical parameters of the inverter 1 exceeding the first preset parameter range, the controller 13 sends a first driving signal to the tripper TX1. Fig.12 As shown, when the release TX1 receives the first drive signal, it drives the moving part d1 to move from position x1 to position x2 (i.e. Fig.12 The moving part d1 is located in the middle of the DC switch S1, thereby driving the locking part M to rotate clockwise around the point Y, and the locking part M is released from the tripping part DCH, causing the tripping part DCH to rotate counterclockwise. Driven by the elastic potential energy stored in the elastic part GB, point B moves to the right, so that the moving contact K1 rotates rapidly clockwise under the pull of the connecting rod mechanism AB, thereby making the moving contact K1 and the static contact K2 in a separated state, and the DC switch S1 is opened. Since the reset part of the moving part d1 of the tripper TX1 is not provided in the operating mechanism of the DC switch S1, after the DC switch S1 is opened, even if the maintenance personnel manually push the operating handle Lf to rotate clockwise, the moving part d1 cannot be driven to reset, and the moving part d1 will always be located at the position x2, so that the tripping part DCH cannot be engaged with the locking part M by operating the operating handle of the DC switch S1, and the DC switch S1 cannot be closed by operating the operating handle of the DC switch S1.

[0077] After the DC switch S1 is opened, it needs to be maintained by professionals. After the maintenance, the controller 13 can detect the electrical parameters of the inverter 1. When the electrical parameters of the inverter 1 are within the first preset parameter range, it means that the fault of the inverter 1 has been eliminated, and the controller 13 sends a third drive signal to the release TX1. When the release TX1 receives the third drive signal, it drives the moving part d1 to move from position x2 to position x1 to achieve the reset of the moving part d1. The locking part M rotates counterclockwise due to the reset of the moving part d1 and stops at Fig.13 As the movable part d1 has been reset, the maintenance personnel can push the operating handle Lf to rotate clockwise, and the operating handle Lf will push the tripping part DCH to rotate clockwise, and the locking part M will be locked by the tripping part DCH, that is, the locking part M is locked with the tripping part DCH, corresponding to Fig.14 After that, the maintenance personnel pushes the operating handle Lf to rotate counterclockwise, so that the tension direction of the elastic member GB exceeds the left side of the connecting rod structure BC. Point B moves to the left under the tension of the elastic member GB, and the connecting rod structure AB pushes the moving contact K1 downward to close, so that the moving contact K1 and the static contact K2 are in a closed state, corresponding to Fig.11 In the switching state shown, the DC switch S1 is closed.

[0078] It is understandable that, in the case of a fault in the inverter 1, the controller 13 controls the DC switch S1 to open by driving the moving parts in the first drive device. Since the DC switch S1 is not provided with a reset part of the moving parts in the first drive device, the maintenance personnel cannot close the DC switch S1 by operating the operating handle of the DC switch S1, thereby avoiding the situation where the DC switch S1 is manually closed when the inverter 1 fails, thereby avoiding the spread of the fault. Only when the controller 13 detects that the fault of the inverter 1 has been eliminated, the controller 13 controls the reset of the moving parts in the first drive device, and then the maintenance personnel can close the DC switch S1 by operating the operating handle of the DC switch S1. Furthermore, it can be ensured that when the inverter 1 fails, the maintenance personnel cannot close the DC switch S1 by operating the operating handle of the DC switch S1 before the fault is eliminated. After professional maintenance is required, the inverter internal controller 13 can further close the switch after detection and confirmation, thereby ensuring the safety of the maintenance personnel.

[0079] In another implementation scenario, during the process of the inverter 1 supplying power to the AC power grid, when a photovoltaic string or its connecting line fails (inverter external fault), the controller 13 sends a first drive signal to the first drive device. When the first drive device receives the first drive signal, it drives the moving part in the first drive device to drive the locking part and the tripping part to trip, so that the moving contact and the static contact of the DC switch S1 are separated. After the photovoltaic string or its connecting line fails and the moving contact and the static contact of the DC switch S1 are separated, the controller 13 immediately sends a third drive signal to the first drive device. When the first drive device receives the third drive signal, it drives the moving part in the first drive device to reset. After the moving part in the first drive device is reset, the operating handle drives the tripping part and the locking part to engage when subjected to external force, and drives the moving contact of the DC switch S1 to contact the static contact.

[0080] That is to say, in this implementation scenario, the first drive device immediately sends the third drive signal after sending the first drive signal, without waiting for the photovoltaic string or its connecting line to eliminate the fault. In this way, the moving part of the first drive device immediately returns to position x1 to achieve reset after reaching x2. Based on debugging requirements, the maintenance personnel can manually push the operating handle Lf to rotate clockwise, and the operating handle Lf pushes the tripping component DCH to rotate clockwise, and the locking component M is locked by the tripping component DCH, that is, the locking component M is engaged with the tripping component DCH. Afterwards, the maintenance personnel pushes the operating handle Lf to rotate counterclockwise, so that the tension direction of the elastic part GB exceeds the left side of the connecting rod structure BC, and point B moves to the left under the tension of the elastic part GB. The connecting rod structure AB pushes the moving contact K1 downward to close, so that the moving contact K1 and the static contact K2 are in a closed state, corresponding to Fig.11 In the switching state shown, the DC switch S1 is closed.

[0081] In some other possible implementations, in order to ensure the safety of maintenance personnel, in the event of a fault in the photovoltaic string or its connecting line, the controller 13 may continue to detect the electrical parameters of the input end of the inverter 1 until it is detected that the electrical parameters of the input end of the inverter 1 are within the second preset parameter range, indicating that the fault of the photovoltaic string and its connecting line has been eliminated, and the controller 13 sends a third drive signal to the first drive device to reset the moving parts in the first drive device. After the moving parts in the first drive device are reset, the DC switch S1 can be manually closed. That is, the maintenance personnel cannot directly manually close the switch, and the inverter must detect and confirm that the fault of the photovoltaic string and its line has been eliminated before resetting the moving parts of the first drive device, so that the maintenance personnel can further manually close the switch.

[0082] Optionally, after the DC switch S1 is opened due to a fault in the photovoltaic string or its connecting line, the controller 13 sends a third drive signal to the first drive device and starts to count the number of closures between the moving contact and the static contact of the DC switch S1. Before the fault in the photovoltaic string or its connecting line is eliminated and the moving contact is separated from the static contact, if the number of the third drive signal sent to the first drive device does not exceed the preset threshold, the third drive signal is sent to the first drive device; when the photovoltaic string or its connecting line fails, if the number of the second drive signal sent to the second drive device exceeds the preset threshold, the third drive signal is stopped from being sent to the first drive device. Since the controller 13 no longer controls the reset of the moving parts in the first drive device when the number of closures of the DC switch S1 is greater than the preset threshold in the case of a fault in the photovoltaic string or its connecting line, it can be ensured that the DC switch S1 can no longer be manually closed when the number of closures of the DC switch S1 is greater than the preset threshold. This approach ensures that in the event of a PV string or its connecting line failure, a certain number of manual closings are allowed to meet the debugging requirements, while also preventing maintenance personnel from closing the circuit breaker multiple times without eliminating the fault, which could cause the fault to spread.

[0083] In the embodiment of the present application, a first driving device that is only controlled by the controller 13 to reset the moving parts is provided in the DC switch S1. When the inverter 1, the photovoltaic string or its connecting line fails, the controller 13 controls the first driving device to open the DC switch S1. After the DC switch S1 is opened due to the failure of the photovoltaic string or its connecting line, the number of times the moving parts in the first driving device are reset does not exceed a preset threshold, so that the DC switch S1 cannot be manually closed when the inverter 1 fails, and the DC switch S1 can be manually closed within a preset number of times when the photovoltaic string or its connecting line fails, thereby effectively avoiding the spread of the fault. In addition, the number of driving devices provided in the DC switch S1 is small, which can effectively reduce the volume and circuit cost of the DC switch S1, thereby effectively reducing the volume and circuit cost of the inverter 1.

[0084] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An inverter, characterized in that: The inverter includes an input end, a DC switch, a plurality of DC / DC converters, a DC bus, a DC / AC converter, a controller and an output end, wherein the input end is used to connect a photovoltaic string, and the output end is used to connect an AC power grid. The DC switch includes an operating handle, an operating mechanism, a moving contact, a stationary contact, a first drive device and a second drive device, wherein: The input ends of the multiple DC / DC converters are connected to the input end of the inverter through the DC switch, and the output ends of the multiple DC / DC converters are connected in parallel to the DC bus; The input end of the DC / AC converter is connected to the DC bus, and the output end of the DC / AC converter is connected to the output end of the inverter; The operating mechanism comprises a locking component, a tripping component, a transmission assembly and a reset component; the operating handle, the tripping component, the reset component and the moving contact are respectively connected to the transmission assembly in a transmission manner; The operating mechanism is used to drive the moving contact and the stationary contact to contact and separate, wherein, when the tripping component is engaged with the locking component, the operating handle can drive the transmission assembly to drive the moving contact and the stationary contact to contact and separate; when the tripping component is disengaged from the locking component, the operating handle cannot drive the transmission assembly to drive the moving contact and the stationary contact to contact and separate; The controller is configured to send a first drive signal to the first drive device when a fault occurs in the inverter; The first driving device is used to drive the moving part in the first driving device to move when receiving the first driving signal, so as to drive the locking part to be disengaged from the tripping part, and to make the transmission assembly drive the moving contact to be separated from the static contact; The controller is further configured to send a second driving signal to the second driving device when a failure occurs in the photovoltaic string or a connection line thereof; The second driving device is used to drive the moving part in the second driving device to move when receiving the second driving signal, so as to drive the locking part to be disengaged from the tripping part, and to make the transmission assembly drive the moving contact to be separated from the static contact; After the second driving device drives the moving contact to separate from the stationary contact, the operating handle is further used to drive the transmission assembly to drive the reset component to move when subjected to an external force, so as to drive the moving component in the second driving device to reset; After the moving part in the second driving device is reset, the operating handle is also used to drive the jumper part to engage with the locking part when subjected to external force, so that the operating handle can drive the transmission assembly to bring the moving contact into contact with the static contact.

2. The inverter according to claim 1, characterized in that: The controller is specifically configured to: in the event of a failure of the photovoltaic string or its connecting line, if the number of times the second driving signal is sent to the second driving device does not exceed a preset threshold, send a second driving signal to the second driving device; The controller is further configured to send the first drive signal to the first drive device when the number of times the second drive signal is sent to the second drive device exceeds a preset threshold and when a fault occurs in the photovoltaic string or a connection line thereof.

3. The inverter according to claim 1 or 2, characterized in that: The controller is also used to send a third driving signal to the first driving device when the inverter fault is eliminated; The first driving device is further used to drive the moving part in the first driving device to reset when receiving the third driving signal; After the moving part in the first drive device is reset, the operating handle is also used to drive the jumper part to engage with the locking part when subjected to external force, so that the operating handle can drive the transmission assembly to bring the moving contact into contact with the static contact.

4. The inverter according to any one of claims 1 to 3, characterized in that: The controller is further configured to determine that a fault occurs in the inverter when an electrical parameter of the inverter exceeds a first preset parameter range, wherein the electrical parameter of the inverter includes a bus voltage value or a bus current value of the DC bus.

5. The inverter according to any one of claims 1 to 4, characterized in that: The controller is also used to determine that a fault occurs in the photovoltaic string or a connection line thereof when an electrical parameter of the photovoltaic string exceeds a second preset parameter range, wherein the electrical parameter of the photovoltaic string includes an output voltage value, an output current value, or a ground insulation resistance value.

6. An inverter, characterized in that: The inverter includes an input end, a DC switch, a plurality of DC / DC converters, a DC bus, a DC / AC converter, a controller and an output end, wherein the input end is used to connect a photovoltaic string, and the output end is used to connect an AC power grid. The DC switch includes an operating handle, an operating mechanism, a moving contact, a stationary contact and a first drive device, wherein: The input ends of the multiple DC / DC converters are connected to the input end of the inverter through the DC switch, and the output ends of the multiple DC / DC converters are connected in parallel to the DC bus; The input end of the DC / AC converter is connected to the DC bus, and the output end of the DC / AC converter is connected to the output end of the inverter; The operating mechanism comprises a locking component, a tripping component, and a transmission assembly; the operating handle, the tripping component, and the moving contact are respectively connected to the transmission assembly in a transmission manner; The operating mechanism is used to drive the moving contact and the stationary contact to contact and separate, wherein, when the tripping component is engaged with the locking component, the operating handle can drive the transmission assembly to drive the moving contact and the stationary contact to contact and separate; when the tripping component is disengaged from the locking component, the operating handle cannot drive the transmission assembly to drive the moving contact and the stationary contact to contact and separate; The controller is configured to send a first driving signal to the first driving device when a fault occurs in the inverter, the photovoltaic string, or a connection line of the photovoltaic string; The first driving device is used to drive the moving part in the first driving device to move when receiving the first driving signal, so as to drive the locking part to be disengaged from the tripping part, and to make the transmission assembly drive the moving contact to be separated from the static contact; The controller is further configured to send a third drive signal to the first drive device when the inverter fault is eliminated; and send a third drive signal to the first drive device before the fault of the photovoltaic string or its connecting line is eliminated and the moving contact is separated from the static contact; The first driving device is further used to drive the moving part in the first driving device to reset when receiving the third driving signal; After the moving part in the first drive device is reset, the operating handle is also used to drive the jumper part to engage with the locking part when subjected to external force, so that the operating handle can drive the transmission assembly to bring the moving contact into contact with the static contact.

7. The inverter according to claim 6, characterized in that: The controller is specifically configured to: before the fault of the photovoltaic string or its connecting line is eliminated and the moving contact is separated from the static contact, if the number of times the third driving signal is sent to the first driving device does not exceed a preset threshold, send a third driving signal to the first driving device; The controller is also used for: when the photovoltaic string or its connecting line fails, if the number of times the third driving signal is sent to the second driving device exceeds a preset threshold, stopping sending the third driving signal to the first driving device.

8. The inverter according to claim 6 or 7, characterized in that: The controller is further configured to determine that a fault occurs in the inverter when an electrical parameter of the inverter exceeds a first preset parameter range, wherein the electrical parameter of the inverter includes a bus voltage value or a bus current value of the DC bus.

9. The inverter according to any one of claims 6 to 8, characterized in that: The controller is also used to determine that a fault occurs in the photovoltaic string or a connection line thereof when an electrical parameter of the photovoltaic string exceeds a second preset parameter range, wherein the electrical parameter of the photovoltaic string includes an output voltage value, an output current value, or a ground insulation resistance value.

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