Inverter and combiner box

Abstract

The utility model discloses an inverter and a combiner box, and relates to the technical field of power electronics. In the inverter, the number of direct-current power supplies connected with any positive pole switch and the number of direct-current power supplies connected with any negative pole switch are smaller than two, and therefore the direct-current power supplies are not connected in parallel in pairs; when the direct-current power supplies are reversely connected, after the corresponding switches are disconnected, reverse connection current cannot occur among the direct-current power supplies, so that the reverse connection direct-current power supplies can be directly disconnected from the switches on the two sides of the reverse connection direct-current power supplies, arc discharge cannot be caused, and the risks of personal electric shock and fire disasters can be further reduced. In addition, different DC / DC conversion circuits are in cross connection with the DC power supply, so that the use number of switches can be reduced.

Description

Technical Field

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

[0002] On the DC side of the inverter, multiple DC power supplies are generally set up and connected through corresponding DC switches. In the related art, there is a situation that after the DC switch is disconnected, abnormal current exists between different DC power supplies; at this time, if the connection between one of the DC power supplies and the DC switches connected to both sides of itself is disconnected, the interruption of the above abnormal current will cause arcing, thereby creating the risk of electric shock and fire. Utility Model Content

[0003] In view of the above problems, the present application provides an inverter and a combiner box to reduce the risk of electric shock and fire. The specific solution is as follows:

[0004] In a first aspect, the present application provides an inverter, comprising: a controller, a DC / AC conversion circuit, at least two DC / DC conversion circuits, at least two positive switches and at least two negative switches; wherein:

[0005] The first side of each of the positive switches is connected to the positive electrode of at least one corresponding DC power supply; the second side of each of the positive switches is connected to the positive electrode of the input end of the corresponding DC / DC conversion circuit;

[0006] The first side of each of the negative switches is connected to the negative electrode of at least one of the DC power supplies; the second side of each of the negative switches is connected to the negative electrode of the input terminal of the DC / DC conversion circuit;

[0007] The number of the same DC power sources connected to any of the positive switches and any of the negative switches is less than 2;

[0008] There is at least one of the positive switch or the negative switch, the number of the DC power supplies connected to it is greater than 1, and there is at least one switch connected to the corresponding pole of the DC power supply in each of the DC power supplies;

[0009] The output end of the DC / DC conversion circuit is connected to the DC side of the DC / AC conversion circuit;

[0010] The AC side of the DC / AC conversion circuit serves as the output end of the inverter;

[0011] The DC / AC conversion circuit, each of the DC / DC conversion circuits, each of the positive switches and each of the negative switches are respectively controlled by the controller.

[0012] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, for the positive electrode switch, if the number of the DC power supplies connected to it is greater than 1, the negative electrodes of the corresponding DC power supplies are respectively connected to different negative electrode switches;

[0013] When the DC / DC conversion circuit is a common positive pole topology, for the negative pole switch, if the number of the DC power supplies connected to it is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to different positive pole switches.

[0014] In a possible implementation, when the first side of the positive switch is connected to one of the DC power supplies, the negative pole of the corresponding DC power supply is connected to the first side of any of the negative switches;

[0015] When the first side of the negative pole switch is connected to one of the DC power sources, the positive pole of the corresponding DC power source is connected to the first side of any of the positive pole switches.

[0016] In a possible implementation, there is at least one switch connected to a number of DC power supplies greater than 1, and the other pole of each DC power supply is connected to a different DC / DC conversion circuit through a corresponding switch.

[0017] In a possible implementation, each of the DC power supplies connected to the positive electrode of the input end of the DC / DC conversion circuit has a negative electrode connected to a different negative electrode switch; or, each of the DC power supplies connected to the negative electrode of the input end of the DC / DC conversion circuit has a positive electrode connected to a different positive electrode switch.

[0018] In a possible implementation, the negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; and the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

[0019] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the cathodes of the DC power supplies connected to the positive electrodes of the input terminals of the DC / DC conversion circuit are respectively connected to different cathode switches;

[0020] When the DC / DC conversion circuit is of a common positive pole topology, the positive poles of the DC power supplies connected to the negative poles of the input terminals of the DC / DC conversion circuit are respectively connected to different positive pole switches.

[0021] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, when the number of the DC power supplies connected to the cathode switch is greater than 1, the positive electrodes of the corresponding DC power supplies are respectively connected to the positive electrodes of the input terminals of different DC / DC conversion circuits through the corresponding positive switches;

[0022] When the DC / DC conversion circuit is a common positive pole topology, when the number of the DC power supplies connected to the positive pole switch is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits through the corresponding negative pole switches.

[0023] In a possible implementation, when the number of the DC / DC conversion circuits is M and all of them are common negative pole topologies, M is an integer greater than 1, and there are at least M+1 negative pole switches, wherein the first side of each of the negative pole switches is connected to at least two DC power supplies, and the positive poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits;

[0024] When the number of the DC / DC conversion circuits is M and all are common positive pole topologies, M is an integer greater than 1, and there are at least M+1 positive pole switches, wherein the first side of each of the positive pole switches is connected to at least two DC power supplies, and the negative poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits.

[0025] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the positive electrode of the input end of the DC / DC conversion circuit, which is connected to the negative electrodes of each of the DC power supplies, is respectively connected to different DC / DC conversion circuits through corresponding negative electrode switches;

[0026] When the DC / DC conversion circuit is of a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit is connected to the positive poles of the DC power supplies and is connected to different DC / DC conversion circuits through corresponding positive pole switches.

[0027] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one positive switch;

[0028] When the DC / DC conversion circuit is in a common positive pole topology, the negative pole of the input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one negative pole switch.

[0029] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the second sides of the cathode switches are connected, and after being connected, they are respectively connected to the cathodes of the input terminals of different DC / DC conversion circuits;

[0030] When the DC / DC conversion circuit is of a common positive pole topology, the second sides of the positive pole switches are connected to each other, and after being connected, they are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits.

[0031] In a possible implementation, after the switch is turned off, there is no parallel connection relationship between any two of the DC power supplies.

[0032] In a possible implementation, the switches are grouped and integrated into different linkage switches, or all the switches are integrated into the same linkage switch.

[0033] In a possible implementation, each switch is disconnected and controlled manually or by a controller.

[0034] A second aspect of the present application provides a combiner box, comprising: a controller, at least two DC / DC conversion circuits, at least two positive switches and at least two negative switches; wherein:

[0035] The first side of each of the positive switches is respectively used as the positive input terminal of the combiner box, and is used to connect the positive electrode of at least one corresponding DC power supply; the second side of each of the positive switches is respectively connected to the positive input terminal of the corresponding DC / DC conversion circuit;

[0036] The first side of each of the negative switches is respectively used as the negative input terminal of the combiner box, and is used to connect the negative electrode of at least one of the DC power supplies; the second side of each of the negative switches is respectively connected to the negative electrode of the input terminal of the corresponding DC / DC conversion circuit;

[0037] The number of the same DC power sources connected to any of the positive switches and any of the negative switches is less than 2;

[0038] There is at least one of the positive switch or the negative switch, the number of the DC power supplies connected to it is greater than 1, and there is at least one switch connected to the corresponding pole of the DC power supply in each of the DC power supplies;

[0039] The output end of the DC / DC conversion circuit serves as the output end of the combiner box;

[0040] Each of the DC / DC conversion circuits, each of the positive switches and each of the negative switches are controlled by the controller respectively.

[0041] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, for the positive electrode switch, if the number of the DC power supplies connected to it is greater than 1, the negative electrodes of the corresponding DC power supplies are respectively connected to different negative electrode switches;

[0042] When the DC / DC conversion circuit is a common positive pole topology, for the negative pole switch, if the number of the DC power supplies connected to it is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to different positive pole switches.

[0043] In a possible implementation, when the first side of the positive switch is connected to one of the DC power supplies, the negative pole of the corresponding DC power supply is connected to the first side of any of the negative switches;

[0044] When the first side of the negative pole switch is connected to one of the DC power sources, the positive pole of the corresponding DC power source is connected to the first side of any of the positive pole switches.

[0045] In a possible implementation, there is at least one switch connected to a number of DC power supplies greater than 1, and the other pole of each DC power supply is connected to a different DC / DC conversion circuit through a corresponding switch.

[0046] In a possible implementation, each of the DC power supplies connected to the positive electrode of the input end of the DC / DC conversion circuit has a negative electrode connected to a different negative electrode switch; or, each of the DC power supplies connected to the negative electrode of the input end of the DC / DC conversion circuit has a positive electrode connected to a different positive electrode switch.

[0047] In a possible implementation, the negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; and the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

[0048] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the cathodes of the DC power supplies connected to the positive electrodes of the input terminals of the DC / DC conversion circuit are respectively connected to different cathode switches;

[0049] When the DC / DC conversion circuit is of a common positive pole topology, the positive poles of the DC power supplies connected to the negative poles of the input terminals of the DC / DC conversion circuit are respectively connected to different positive pole switches.

[0050] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, when the number of the DC power supplies connected to the cathode switch is greater than 1, the positive electrodes of the corresponding DC power supplies are respectively connected to the positive electrodes of the input terminals of different DC / DC conversion circuits through the corresponding positive switches;

[0051] When the DC / DC conversion circuit is a common positive pole topology, when the number of the DC power supplies connected to the positive pole switch is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits through the corresponding negative pole switches.

[0052] In a possible implementation, when the number of the DC / DC conversion circuits is M and all of them are common negative pole topologies, M is an integer greater than 1, and there are at least M+1 negative pole switches, wherein the first side of each of the negative pole switches is connected to at least two DC power supplies, and the positive poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits;

[0053] When the number of the DC / DC conversion circuits is M and all are common positive pole topologies, M is an integer greater than 1, and there are at least M+1 positive pole switches, wherein the first side of each of the positive pole switches is connected to at least two DC power supplies, and the negative poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits.

[0054] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the positive electrode of the input end of the DC / DC conversion circuit, which is connected to the negative electrodes of each of the DC power supplies, is respectively connected to different DC / DC conversion circuits through corresponding negative electrode switches;

[0055] When the DC / DC conversion circuit is of a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit is connected to the positive poles of the DC power supplies and is connected to different DC / DC conversion circuits through corresponding positive pole switches.

[0056] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one positive switch;

[0057] When the DC / DC conversion circuit is in a common positive pole topology, the negative pole of the input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one negative pole switch.

[0058] In a possible implementation, when the DC / DC conversion circuit is a common cathode topology, the second sides of the cathode switches are connected, and after being connected, they are respectively connected to the cathodes of the input terminals of different DC / DC conversion circuits;

[0059] When the DC / DC conversion circuit is of a common positive pole topology, the second sides of the positive pole switches are connected to each other, and after being connected, they are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits.

[0060] In a possible implementation, after the switch is turned off, there is no parallel connection relationship between any two of the DC power supplies.

[0061] In a possible implementation, the switches are grouped and integrated into different linkage switches, or all the switches are integrated into the same linkage switch.

[0062] In a possible implementation, each switch is disconnected and controlled manually or by a controller.

[0063] By means of the above technical solution, the inverter provided by the present application connects the corresponding poles of multiple DC power supplies through the first side of each positive and negative switch, and connects at least two DC / DC conversion circuits through the second side of each positive and negative switch; and the number of the DC power supplies connected to any positive switch and the DC power supplies connected to any negative switch belonging to the same DC power supply is less than 2, so that after the switch is disconnected, there is no parallel connection relationship between the DC power supplies; that is, after the switch is disconnected, no abnormal current will appear between any two DC power supplies, so that any DC power supply and the switches on both sides thereof can be directly disconnected without causing arcing, thereby reducing the risk of electric shock and fire. In addition, there is at least one positive switch or negative switch, the number of DC power supplies connected to it is greater than 1, and there is at least one DC power supply in each corresponding DC power supply, the other pole of which is connected to the switch connected to the corresponding pole of the input terminal of another DC / DC conversion circuit, so that the switch that needs to be separately equipped to avoid the parallel connection relationship when the DC power supply and other DC power supplies are connected to the corresponding pole of the input terminal of the same DC / DC conversion circuit can be omitted, and the number of switches used can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0065] Figure 1 A schematic diagram of the structure of an inverter provided in an embodiment of the present application;

[0066] Figure 2 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0067] Figure 3 A topological structure diagram of a Boost circuit provided in an embodiment of the present application;

[0068] Figure 4 A topological structure diagram of a high-voltage Boost circuit provided in an embodiment of the present application;

[0069] Figure 5for Figure 3 A mirror image of the topology shown;

[0070] Figure 6 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0071] Figure 7 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0072] Figure 8 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0073] Fig. 9 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0074] Fig.10 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0075] Fig.11 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0076] Fig.12 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0077] Fig.13 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0078] Fig.14 Another structural schematic diagram of an inverter provided in an embodiment of the present application;

[0079] Fig.15 A schematic diagram of the structure of a linkage switch provided in an embodiment of the present application. DETAILED DESCRIPTION

[0080] The following describes the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation method section of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0081] The embodiments of the present application are described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. It is known to ordinary technicians in this field that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0082] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and need not be used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, which is only to describe the distinction mode adopted by the objects of the same attributes when describing in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0083] The embodiment of the present application provides an inverter to reduce the risk of electric shock and fire. The specific scheme is as follows:

[0084] See also Figure 1 The inverter includes: a controller 30, a DC / AC conversion circuit 20, at least two DC / DC conversion circuits 10, at least two positive switches ( Figure 1 Two positive switches K1 and K4 are used as examples) and at least two negative switches ( Figure 1 Two negative pole switches K2 and K3 are used as examples for demonstration); where:

[0085] The first side of each positive switch is connected to the positive pole of at least one corresponding DC power source. In practical applications, the DC power source may refer to a photovoltaic unit, such as a photovoltaic module or a photovoltaic string, in which case the inverter is a photovoltaic inverter; the DC power source may also refer to an energy storage unit, such as a battery pack or a battery cluster, in which case the inverter is an energy storage converter; this is not limited here and depends on the specific application environment. Figure 1 The photovoltaic unit is used as an example in the following related figures. Figure 1 The first side of the positive switch K1 is connected to the positive pole PV1+ of the photovoltaic unit PV1 and the positive pole PV2+ of the photovoltaic unit PV2; the first side of the positive switch K4 is connected to the positive pole PV4+ of the photovoltaic unit PV4 and the positive pole PV3+ of the photovoltaic unit PV3.

[0086] The second side of each positive switch is connected to the positive input terminal of the corresponding DC / DC conversion circuit 10 . Figure 1 In the example, the number of DC / DC conversion circuits 10 is 2, such as DC / DC conversion circuit #1 and DC / DC conversion circuit #2 shown in the figure. Figure 1 The positive switch K1 in the embodiment has a second side connected to the positive input terminal of the DC / DC conversion circuit #1; Figure 1 The positive switch K4 in the embodiment has a second side connected to the positive input terminal of the DC / DC conversion circuit #2.

[0087] The first side of each negative switch is connected to the negative electrode of at least one corresponding DC power source. Figure 1 In the embodiment, the first side of the negative switch K2 is connected to the negative pole PV1- of the photovoltaic unit PV1 and the negative pole PV3- of the photovoltaic unit PV3; the first side of the negative switch K3 is connected to the negative pole PV2- of the photovoltaic unit PV2 and the negative pole PV4- of the photovoltaic unit PV4.

[0088] The second side of each negative switch is connected to the negative input terminal of the corresponding DC / DC conversion circuit 10. Figure 1 The negative electrode switch K2 in the embodiment has a second side connected to the negative electrode of the input terminal of the DC / DC conversion circuit #1; Figure 1 The negative electrode switch K3 in the circuit has a second side connected to the negative electrode of the input terminal of the DC / DC conversion circuit #2.

[0089] The output end of the DC / DC conversion circuit 10 is connected to the DC side of the DC / AC conversion circuit 20. In practical applications, the output end of each DC / DC conversion circuit 10 can be connected in parallel to the DC side of the DC / AC conversion circuit 20 through a DC bus (including a positive electrode BUS+ and a negative electrode BUS-). The AC side of the DC / AC conversion circuit 20, as the output end of the inverter, can be used to connect to a power grid and / or a load.

[0090] In practical applications, the DC / DC conversion circuit 10 has a variety of optional topologies; for example, when the DC power supply is a photovoltaic unit, the DC / DC conversion circuit 10 can use a Boost circuit, a Buck circuit, a Buck-Boost circuit, etc.; and when the DC power supply is an energy storage unit, the DC / DC conversion circuit 10 can use a bidirectional Buck-Boost circuit, a bidirectional Boost-Buck circuit, a bidirectional Cuk circuit, a bidirectional Sepic-Zeta circuit, a bidirectional two-bridge arm Buck-Boost circuit, a three-phase staggered parallel DC-DC conversion topology, a phase-shifted full-bridge topology, a full-bridge isolated voltage source topology, a full-bridge isolated current source topology, etc.; the specific structure of each circuit can refer to the prior art, and will not be repeated here. The topology selection of the DC / DC conversion circuit 10 depends on its specific application environment, all of which are within the protection scope of this application. The DC / AC conversion circuit 20 can have a variety of optional topologies, such as an H-bridge inverter topology, a three-phase midpoint clamped inverter topology, etc., which are not limited here and can be determined according to its specific application environment. The signal input end of the DC / AC conversion circuit 20 , the signal input end of each DC / DC conversion circuit 10 , the signal input end of each positive switch and the signal input end of each negative switch are respectively connected to the controller 30 to receive the control signal sent by the controller 30 .

[0091] The DC / AC conversion circuit 20, each DC / DC conversion circuit 10, each positive switch and each negative switch are respectively controlled by the controller 30. That is, the controller 30 can control the on and off of each switch, and can also control the operating status of the DC / AC conversion circuit 20 and each DC / DC conversion circuit 10; the specific control principle can be referred to the prior art, which will not be elaborated here. In addition, when a fault occurs in the system where the inverter is located, some or all switches in the inverter can be disconnected manually or by the controller 30 to achieve fault isolation between the DC power supply and the inverter. Possible faults in the system include, but are not limited to: reverse connection of the DC power supply, short circuit of the DC power supply, short circuit of the DC / DC conversion circuit 10 and short circuit of the DC / AC conversion circuit 20.

[0092] Furthermore, the number of the same DC power sources connected to any positive switch and any negative switch is less than 2. Figure 1 As shown in , the positive switch K1 and the negative switch K2 are only connected to one same photovoltaic unit PV1, the positive switch K1 and the negative switch K3 are only connected to one same photovoltaic unit PV2, the positive switch K4 and the negative switch K2 are only connected to one same photovoltaic unit PV3, and the positive switch K4 and the negative switch K3 are only connected to one same photovoltaic unit PV4. This setting ensures that there is no parallel connection between the DC power supplies after the switches are disconnected. In this case, if any DC power supply is reversely connected, that is, its positive pole is connected to the negative switch to which its negative pole should be connected, and its negative pole is connected to the positive switch to which its positive pole should be connected, then the connection between it and the subsequent circuit can be cut off by disconnecting the switches connected on both sides, such as disconnecting multiple switches including the switches connected on both sides or even all switches; moreover, when the corresponding switches are disconnected, since there is no parallel connection relationship between each DC power supply, the reverse-connected DC power supply will not generate reverse current with any other positively connected DC power supply, so that the reverse-connected DC power supply and the switches on both sides can be directly disconnected without causing arcing, thereby reducing the risk of electric shock and fire.

[0093] In addition, when the number of the same DC power source connected to any positive switch and any negative switch is less than 2, the number can be 1 or 0; for example, see Figure 2 The positive switch K4 is connected to the photovoltaic units PV3 and PV4, while the negative switch K2' is connected to the photovoltaic unit PV2. The DC power supplies connected to the two are different, and there is no parallel connection relationship between the DC power supplies, which is also within the protection scope of this application.

[0094] If different DC power supplies are connected in parallel after the switch is disconnected, abnormal current may exist between these DC power supplies. For example, when the DC power supply is reversed, reverse current will exist between the reversed DC power supply and other parallel DC power supplies. When the voltages between different DC power supplies are inconsistent, the DC power supply with a lower voltage will accept the reverse current from other parallel DC power supplies. The following text uses reverse current as an example to illustrate that when a DC power supply is reversed, in order to ensure the safety of the DC power supply, the switches on both sides of the reversed DC power supply or more switches including it can be controlled to be disconnected. However, after the corresponding switch is disconnected, reverse current will exist between the reversed DC power supply and other parallel DC power supplies. At this time, if the connection between the reversed DC power supply and the switches connected to both sides of it is disconnected, arcing will occur due to the interruption of the reverse current, thereby creating the risk of electric shock and fire.

[0095] The inverter provided in this embodiment is connected to the corresponding poles of multiple DC power supplies through the first side of each positive and negative switch, and is connected to at least two DC / DC conversion circuits 10 through the second side of each positive and negative switch; and the number of the same DC power supplies connected to any positive switch and any negative switch is less than 2, so that there is no parallel connection relationship between the DC power supplies after the switches are disconnected; that is, when the switches are disconnected, no abnormal current such as reverse current and backflow current will appear between any two DC power supplies, so that the reverse-connected DC power supply or other DC power supplies and the switches on both sides of them can be directly disconnected without causing arcing, thereby reducing the risk of electric shock and fire.

[0096] It is worth mentioning that in order to avoid arcing caused by reverse current disconnection in the existing technical solutions, in the photovoltaic inverter application scenario, you can wait until the light on the photovoltaic site is very low and the current of the photovoltaic unit is less than the limit value, and then disconnect the connection between the reverse photovoltaic unit and the switches on both sides of it; however, this will result in the inability to perform maintenance in time when a reverse fault occurs on site, thereby causing a loss of power generation.

[0097] In this embodiment, since there is no parallel connection relationship between the DC power supplies after the switch is disconnected, when a reverse connection fault occurs, after the corresponding switch is disconnected, the connection between the reverse-connected DC power supply and the switches connected on both sides can be directly disconnected, and then the reverse-connected DC power supply can be connected in the forward direction to achieve maintenance; in the photovoltaic inverter application scenario, there is no need to wait for the light at the photovoltaic site to become smaller, so the loss of power generation can be avoided.

[0098] In addition, in this embodiment, there is also a configuration that: there is at least one positive switch or negative switch, the number of DC power supplies connected to it is greater than 1, and there is at least one DC power supply in each corresponding DC power supply whose other pole is connected to a switch connected to a corresponding pole of the input terminal of another DC / DC conversion circuit 10. Figure 1As shown in, for the positive switch K1 connected to the positive pole of the input end of the DC / DC conversion circuit #1, the negative pole PV1- of the photovoltaic cell PV1 connected thereto is still connected to the DC / DC conversion circuit #1 through the negative switch K2, while the negative pole PV2- of the photovoltaic cell PV2 connected thereto is connected to the negative switch K3 connected to the negative pole of the input end of the DC / DC conversion circuit #2; for the negative switch K2 connected to the negative pole of the input end of the DC / DC conversion circuit #1, the positive pole PV1+ of the photovoltaic cell PV1 connected thereto is still connected to the DC / DC conversion circuit #1 through the positive switch K1, while the positive pole PV3+ of the photovoltaic cell PV3 connected thereto is connected to the positive switch K3 connected to the positive pole of the input end of the DC / DC conversion circuit #2. 4; for the positive switch K4 connected to the positive pole of the input end of the DC / DC conversion circuit #2, the negative pole PV4- of the photovoltaic cell PV4 connected thereto is still connected to the DC / DC conversion circuit #2 through the negative switch K3, while the negative pole PV3- of the photovoltaic cell PV3 connected thereto is connected to the negative switch K2 connected to the negative pole of the input end of the DC / DC conversion circuit #1; for the negative switch K3 connected to the negative pole of the input end of the DC / DC conversion circuit #2, the positive pole PV4+ of the photovoltaic cell PV4 connected thereto is still connected to the DC / DC conversion circuit #2 through the positive switch K4, while the positive pole PV2+ of the photovoltaic cell PV2 connected thereto is connected to the positive switch K1 connected to the positive pole of the input end of the DC / DC conversion circuit #1.

[0099] That is, for Figure 1 As for the structure shown, when the positive pole of the input end of the DC / DC conversion circuit #1 is connected to the photovoltaic units PV1 and PV2, and the positive pole of the input end of the DC / DC conversion circuit #2 is connected to the photovoltaic units PV3 and PV4, the negative pole of the input end of the DC / DC conversion circuit #1 is connected to both the photovoltaic unit PV1 connected to the positive pole of its own input end and the photovoltaic unit PV3 connected to the positive pole of the input end of the other DC / DC conversion circuit #2 through the same negative pole switch K2; in addition, the negative pole of the input end of the DC / DC conversion circuit #2 is connected to both the photovoltaic unit PV4 connected to the positive pole of its own input end and the photovoltaic unit PV2 connected to the positive pole of the input end of the other DC / DC conversion circuit #1 through the same negative pole switch K3.

[0100] The above arrangement enables cross-connection of DC power supplies between different DC / DC conversion circuits 10, and thus makes it unnecessary for the DC power supply with one pole directly connected due to a shared switch to be equipped with a different switch connected to the same DC / DC conversion circuit 10 for the other pole to avoid parallel connection. Instead, the DC power supply can be connected to the corresponding pole switches of different DC / DC conversion circuits 10 to avoid parallel connection. Therefore, this arrangement can reduce the number of switches used.

[0101] It is worth mentioning that Figure 1 In the figure, the number of DC / DC conversion circuits 10 is 2, the number of positive and negative switches is also 2, and the number of DC power supplies connected to each switch is also 2. In actual applications, the number of DC / DC conversion circuits 10 can be more, the number of positive and negative switches can also be more and do not need to be equal, the number of DC power supplies connected to each switch can also be more and do not need to be equal. Other optional quantity settings will be shown below, but they are not intended to limit the present application. In actual applications, the number of each device or component can be determined according to actual conditions, as long as there is no parallel connection between the DC power supplies, and there is a cross-connected DC power supply between at least one DC / DC conversion circuit 10 and other DC / DC conversion circuits 10, it is within the protection scope of the present application.

[0102] For example, see Figure 2 ( Figure 2 The controller 30 is omitted in the following related figures. Figure 1 Compared with the above, a negative switch K2' is added. At this time, for photovoltaic units PV1 and PV2, although their positive poles are connected due to the common positive switch K1, their negative poles are connected to different negative switches K2 and K2', respectively, so the two still do not form a parallel connection relationship; and for photovoltaic units PV3 and PV4, although their positive poles are connected due to the common positive switch K4, their negative poles are connected to different negative switches K2 and K3, respectively, so the two do not form a parallel connection relationship; and, although photovoltaic units PV1 and PV On the basis of being connected to the same DC / DC conversion circuit #1, it is necessary to equip the photovoltaic unit PV2 with another negative pole switch K2' so that there is no parallel connection relationship between the two. However, the photovoltaic unit PV3 is not equipped with a separate negative pole switch to be connected to the same DC / DC conversion circuit #2 as the photovoltaic unit PV4. Instead, the negative pole switch K2 connected to the DC / DC conversion circuit #1 is used to make the photovoltaic units PV3 and PV4 not be connected in parallel. Therefore, one negative pole switch can still be omitted, which also has the advantage of reducing the number of switches used.

[0103] In practical applications, in order to avoid parallel connection between each DC power supply, for each DC power supply connected at one pole, the other pole thereof can be set to be connected to the same DC / DC conversion circuit 10 through the corresponding switch, or the other pole thereof can be set to be connected to the switch for accessing different DC / DC conversion circuits 10; as long as there are two DC power supplies using the latter connection, the switch equipped for using the former connection can be reduced; that is, in practical applications, it can be set that: there is at least one switch connected to a number of DC power supplies greater than 1, and the other poles of the corresponding DC power supplies are connected to different DC / DC conversion circuits 10 through the corresponding switches.

[0104] In one example, in the inverter: for any switch, if the number of DC power sources connected to it is greater than 1, the other poles of the corresponding DC power sources are connected to different DC / DC conversion circuits 10 through corresponding switches.

[0105] In practical applications, in the inverter, for each DC power supply connected to one pole, if the number is 2, then the other pole is respectively connected to switches for accessing different DC / DC conversion circuits 10; and if the number is greater than 2, then the other pole can be set to be connected to switches for accessing different DC / DC conversion circuits 10 to save as many switches as possible; or, only at least one of them can be set to access another DC / DC conversion circuit 10, which can still reduce the corresponding number of switches. That is, for each DC power supply connected to one pole, if the number is greater than 2, the DC / DC conversion circuits 10 connected to the other pole can be completely different or partially different, all within the protection scope of this application.

[0106] On the basis of the above embodiments, this embodiment gives some detailed descriptions of the structure of the inverter. For example, the DC / DC conversion circuit 10 has a variety of optional topologies, but according to the connection relationship of its internal components, it can be divided into two topologies: common positive pole and common negative pole. For example, Figure 3 The boost circuit shown and Figure 4 The high-voltage Boost circuits shown are all common cathode topologies. As can be seen from the figure, the negative electrode of the input terminal and the negative electrode of the output terminal of this circuit are directly connected inside the circuit, that is, the input terminal and the output terminal of this circuit are connected to the common cathode, so it can be called a common cathode topology; and the topology in which the input terminal and the output terminal are connected to the common positive electrode is a common positive topology, such as Figure 5 As shown, it is Figure 3 Mirror image of the topology shown. Figures 3 to 5 This is only an exemplary description of the optional topology of the DC / DC conversion circuit 10 , and other topologies in the prior art are also within the protection scope of this application.

[0107] When the DC / DC conversion circuit 10 is a common negative pole topology, the negative poles of the input and output ends of each DC / DC conversion circuit 10 are connected, and the inverter can be called a common negative pole inverter; when the DC / DC conversion circuit 10 is a common positive pole topology, the positive poles of the input and output ends of each DC / DC conversion circuit 10 are connected, and the inverter can be called a common positive pole inverter.

[0108] The following examples illustrate the structures of the inverter in the DC / DC conversion circuit 10 using the above two topologies:

[0109] When the DC / DC conversion circuit 10 is a common cathode topology, for any positive switch in the inverter, if the number of DC power sources connected to it is greater than 1, the negative electrodes of the corresponding DC power sources are connected to different negative switches. Figure 6 Take the case where the number of DC / DC conversion circuits 10 is 2, the number of positive switches is 4, the number of negative switches is 2, and each DC / DC conversion circuit 10 is connected to 3 photovoltaic units respectively as an example for demonstration; wherein the positive pole of the input end of the DC / DC conversion circuit #1 is connected to the first photovoltaic unit PV1, the second photovoltaic unit PV2 and the third photovoltaic unit PV3, and the positive pole of the input end of the DC / DC conversion circuit #2 is connected to the fourth photovoltaic unit PV4, the fifth photovoltaic unit PV5 and the sixth photovoltaic unit PV6. The positive pole PV1+ of the first photovoltaic unit PV1 is connected to the first switch K11, the positive pole PV2+ of the second photovoltaic unit PV2 and the positive pole PV3+ of the third photovoltaic unit PV3 are both connected to the second switch K12, the negative pole PV1- of the first photovoltaic unit PV1 and the negative pole PV2- of the second photovoltaic unit PV2 are both connected to the third switch K13, and the negative pole PV3- of the third photovoltaic unit PV3 is connected to the fourth switch K14. The positive pole PV4+ of the fourth photovoltaic unit PV4 and the positive pole PV5+ of the fifth photovoltaic unit PV5 are both connected to the sixth switch K16, the positive pole PV6+ of the sixth photovoltaic unit PV6 is connected to the fifth switch K15, the negative pole PV4- of the fourth photovoltaic unit PV4 is connected to the third switch K13, and the negative pole PV5- of the fifth photovoltaic unit PV5 and the negative pole PV6- of the sixth photovoltaic unit PV6 are both connected to the fourth switch K14. That is, the second switch K12 connects two photovoltaic cells PV2 and PV3, wherein the negative pole PV2- of the second photovoltaic cell PV2 is connected to the negative pole of the input terminal of the DC / DC conversion circuit #1 through the third switch K13, and the negative pole PV3- of the third photovoltaic cell PV3 is connected to the negative pole of the input terminal of the DC / DC conversion circuit #2 through the fourth switch K14; the sixth switch K16 connects two photovoltaic cells PV4 and PV5, wherein the negative pole PV4- of the fourth photovoltaic cell PV4 is connected to the negative pole of the input terminal of the DC / DC conversion circuit #1 through the third switch K13, and the negative pole PV5- of the fifth photovoltaic cell PV5 is connected to the negative pole of the input terminal of the DC / DC conversion circuit #2 through the fourth switch K14. Figure 6 In the structure shown, after each switch is disconnected, there is no parallel connection relationship between each photovoltaic unit; when there is a reverse connection of the photovoltaic unit, after the corresponding switch is disconnected, there is no reverse current in each photovoltaic unit, and the connection between the reverse-connected photovoltaic unit and the switches on both sides of it can be directly disconnected, without arcing, and there is no risk of electric shock or fire.

[0110] In addition, when the DC / DC conversion circuit 10 is a common cathode topology, when there is a first side of a positive switch connected to a DC power source, the negative electrode of the corresponding DC power source is connected to the first side of any negative switch; for example, Figure 6 In the embodiment, the negative electrode PV1- of the first photovoltaic unit PV1 can be connected to the first side of the third switch K13 (such as Figure 6 ), or it can be connected to the first side of the fourth switch K14 (not shown); the negative electrode PV6- of the sixth photovoltaic unit PV6 can be connected to the first side of the fourth switch K14 (as shown in Figure 6 ), and the first side of the third switch K13 may also be connected (not shown).

[0111] In practical applications, in order to reduce the number of switches, each negative electrode of the DC / DC conversion circuit 10 can be provided with only one negative electrode switch, that is, if the number of DC / DC conversion circuits 10 is M, M is an integer greater than 1, then the number of negative electrode switches is also M, and the second sides of the M negative electrode switches are respectively connected to the negative electrodes of the input terminals of different DC / DC conversion circuits 10. At this time, the number of DC power supplies connected to the first side of each positive electrode switch is less than or equal to M; when there are at least two DC power supplies connected to the first side of the positive electrode switch, the negative electrodes of the corresponding DC power supplies are respectively connected to the first sides of different negative electrode switches; Figure 6 That is, the demonstration is carried out using M=2 as an example.

[0112] Figure 7 Another example when M=2 is shown, in which the positive input terminals of DC / DC conversion circuit #1 and DC / DC conversion circuit #2 are each connected to 6 photovoltaic units, PVj+ represents the positive terminal of the jth photovoltaic unit, PVj- represents the negative terminal of the jth photovoltaic unit, and j is any value from 1 to 12; after all switches are disconnected, there is no parallel connection relationship between any two photovoltaic units.

[0113] Figure 8 Another example when M=2 is shown, in which the positive input terminal of the DC / DC conversion circuit #1 is connected to 9 photovoltaic units, and the positive input terminal of the DC / DC conversion circuit #2 is connected to 8 photovoltaic units, PVj+ represents the positive pole of the j-th photovoltaic unit, PVj- represents the negative pole of the j-th photovoltaic unit, and j is any value from 1 to 17; after all switches are disconnected, there is no parallel connection relationship between each photovoltaic unit.

[0114] When the DC / DC conversion circuit 10 is a common positive pole topology, for any negative pole switch, if the number of DC power sources connected to it is greater than 1, the positive poles of the corresponding DC power sources are connected to different positive pole switches. Fig. 9Take the case where the number of DC / DC conversion circuits 10 is 2, the number of positive switches is 2, the number of negative switches is 4, and each DC / DC conversion circuit 10 is connected to 3 photovoltaic units respectively as an example for demonstration; wherein the negative pole of the input end of the DC / DC conversion circuit #1 is connected to the first photovoltaic unit PV1, the second photovoltaic unit PV2 and the third photovoltaic unit PV3, and the negative pole of the input end of the DC / DC conversion circuit #2 is connected to the fourth photovoltaic unit PV4, the fifth photovoltaic unit PV5 and the sixth photovoltaic unit PV6. The negative pole PV1- of the first photovoltaic unit PV1 is connected to the first switch K21, the negative pole PV2- of the second photovoltaic unit PV2 and the negative pole PV3- of the third photovoltaic unit PV3 are connected to the second switch K22, the positive pole PV1+ of the first photovoltaic unit PV1 and the positive pole PV2+ of the second photovoltaic unit PV2 are connected to the third switch K23, and the positive pole PV3+ of the third photovoltaic unit PV3 is connected to the fourth switch K24. The negative pole PV4- of the fourth photovoltaic unit PV4 and the negative pole PV5- of the fifth photovoltaic unit PV5 are connected to the sixth switch K26, the negative pole PV6- of the sixth photovoltaic unit PV6 is connected to the fifth switch K25, the positive pole PV4+ of the fourth photovoltaic unit PV4 is connected to the third switch K23, the positive pole PV5+ of the fifth photovoltaic unit PV5 and the positive pole PV6+ of the sixth photovoltaic unit PV6 are connected to the fourth switch K24. That is, the second switch K22 connects two photovoltaic cells PV2 and PV3, wherein the positive pole PV2+ of the second photovoltaic cell PV2 is connected to the positive pole of the input terminal of the DC / DC conversion circuit #1 through the third switch K23, and the positive pole PV3+ of the third photovoltaic cell PV3 is connected to the positive pole of the input terminal of the DC / DC conversion circuit #2 through the fourth switch K24; the sixth switch K26 connects two photovoltaic cells PV4 and PV5, wherein the positive pole PV4+ of the fourth photovoltaic cell PV4 is connected to the positive pole of the input terminal of the DC / DC conversion circuit #1 through the third switch K23, and the positive pole PV5+ of the fifth photovoltaic cell PV5 is connected to the positive pole of the input terminal of the DC / DC conversion circuit #2 through the fourth switch K24. Fig. 9 In the structure shown, after each switch is disconnected, there is no parallel connection relationship between each photovoltaic unit; when there is a reverse connection of the photovoltaic unit, after the corresponding switch is disconnected, there is no reverse current in each photovoltaic unit, and the connection between the reverse-connected photovoltaic unit and the switches on both sides of it can be directly disconnected, without arcing, and there is no risk of electric shock or fire.

[0115] In addition, when the DC / DC conversion circuit 10 is a common positive pole topology, when there is a first side of a negative pole switch connected to a DC power source, the positive pole of the corresponding DC power source is connected to the first side of any positive pole switch; for example, Fig. 9 In the embodiment, the positive electrode PV1+ of the first photovoltaic unit PV1 can be connected to the first side of the third switch K23 (such as Fig. 9), or it can be connected to the first side of the fourth switch K24 (not shown); the positive electrode PV6+ of the sixth photovoltaic unit PV6 can be connected to the first side of the fourth switch K24 (as shown in Fig. 9 ), and the first side of the third switch K23 may also be connected (not shown).

[0116] In practical applications, in order to reduce the number of switches, if the number of DC / DC conversion circuits 10 is M, the number of positive switches can be set to M, and the second sides of the M positive switches are respectively connected to the positive input terminals of different DC / DC conversion circuits 10; the number of DC power supplies connected to the first side of each negative switch is less than or equal to M; when the first side of a negative switch is connected to at least two DC power supplies, the positive poles of the corresponding DC power supplies are respectively connected to the first sides of different positive switches. Fig. 9 That is, the demonstration is performed using M=2 as an example; when M=2, the case where the number of switches and / or the number of photovoltaic units is greater is no longer demonstrated separately, and the principle is the same as that of the common negative pole topology.

[0117] in addition, Figures 6 to 9 This is only a partial display based on M=2. When M=2, the number of switches and / or photovoltaic units can be greater, so no further display is given. Furthermore, the value of M can also be greater than 2. The situation when M>2 can be inferred from the above description and no further display is given.

[0118] In practical applications, if there is no cross-connection of DC power supplies between a DC / DC conversion circuit and other DC / DC conversion circuits, then when a reverse-connected DC power supply appears in the DC power supplies connected to the DC / DC conversion circuit, after the corresponding switch is disconnected, the reverse-connected DC power supply may form a series connection relationship with other DC power supplies at its two poles due to the shared switch, thereby causing it to form a branch connected in series with the DC power supplies connected to its two poles; the two switches at both ends of the branch will withstand 3 times the DC power supply voltage, which places very high requirements on the voltage design of the switch.

[0119] To solve the above problem, in this embodiment, the following settings are made for each DC power supply connected to the same DC / DC conversion circuit: when the positive or negative poles of the two DC power supplies are not connected to the same switch, their opposite poles are also connected to different switches; in this case, if a DC power supply reverse connection fault occurs, even if the corresponding reverse-connected DC power supply is connected in series with other DC power supplies, there will only be at most two DC power supplies in the branch after the series connection, so the switches on both sides of the series branch can withstand at most twice the DC power supply voltage.

[0120] That is, on the basis of the above embodiment, it can be set that: the negative poles of each DC power supply connected to the positive pole of the input end of the DC / DC conversion circuit 10 are connected to different negative pole switches; or, the positive poles of each DC power supply connected to the negative pole of the input end of the DC / DC conversion circuit 10 are connected to different positive pole switches. In other words, there is a situation that: for a DC / DC conversion circuit 10, regardless of whether there is a connection point between the corresponding poles of each DC power supply connected to the positive pole or negative pole of its input end, the opposite poles of these DC power supplies are connected to different switches. If a DC power supply reverse connection fault occurs, after the corresponding reverse-connected DC power supply is connected in series with other DC power supplies, the switches on both sides can withstand at most twice the DC power supply voltage.

[0121] by Figure 6 The structure shown in the figure is used as an example to illustrate that at this time, the three photovoltaic units PV1 to PV3 connected to the positive pole of the input end of the DC / DC conversion circuit #1 are required to be connected to different negative pole switches respectively, see Fig.10 , you can Figure 6 On the basis of the structure shown, a negative pole switch K13' is added to the first photovoltaic unit PV1, so that it and the other two photovoltaic units PV2 and PV3 are respectively connected to different negative pole switches, so that when a photovoltaic unit reverse connection fault occurs, each switch can withstand a maximum of 2 times the DC power supply voltage; similarly, a negative pole switch K14' can be added to the sixth photovoltaic unit PV6, so that it and the other two photovoltaic units PV4 and PV5 are respectively connected to different negative pole switches. Fig.10 In the structure shown, any pole of the input end of the DC / DC conversion circuit 10, the other pole of each DC power source connected thereto is connected to a different switch. That is, in practical applications, it can also be arranged that: the negative poles of each DC power source connected to the positive pole of the input end of the DC / DC conversion circuit 10 are connected to different negative pole switches; and the positive poles of each DC power source connected to the negative pole of the input end of the DC / DC conversion circuit 10 are connected to different positive pole switches.

[0122] for Fig.10 The two negative switches K13' and K14' added in Fig.10 As shown in , the second side thereof is respectively connected to the DC / DC conversion circuit 10 connected to the positive pole of each corresponding photovoltaic unit; or, the second side thereof can also be respectively connected to another DC / DC conversion circuit 10, for example, the second side of the negative pole switch K13' can also be connected Fig.10 The negative input terminal of the DC / DC converter circuit #2 shown in FIG. 1 is not limited here. Fig.10The connection relationship shown in is only an optional example. As long as there is no parallel connection relationship between each DC power supply and there is a cross-connected DC power supply between different DC / DC conversion circuits 10, it is set that there is a pole in the input end of each DC / DC conversion circuit 10, and the other pole connected to each DC power supply is connected to different switches respectively, so that each switch can withstand a maximum of twice the DC power supply voltage when a DC power supply reverse connection fault occurs.

[0123] Specifically, when the DC / DC conversion circuit 10 is a common cathode topology, for any DC / DC conversion circuit 10 , the negative electrodes of the DC power supplies to which the positive electrodes of its input terminals are connected are respectively connected to different cathode switches. Figures 11 to 13 All of them take the number of DC / DC conversion circuits 10 M=2 as an example to show different structures of the inverter; Figures 11 to 13 In the equation, PVj+ represents the positive electrode of the j-th photovoltaic unit, PVj- represents the negative electrode of the j-th photovoltaic unit, and j is Fig.11 is any value between 1 and 10, j is Fig.12 and Fig.13 Any value between 1 and 12.

[0124] Under this setting, when the number of DC power sources connected to any negative switch is greater than 1, the positive poles of the corresponding DC power sources are connected to the positive poles of the input terminals of different DC / DC conversion circuits 10 through the corresponding positive switches. Fig.11 In the example, K41, K42, K49 and K410 are positive switches, and K43 to K48 are negative switches; Fig.11 As shown in FIG, the negative pole switches K44 to K47 correspond to two connected photovoltaic units respectively, and their positive poles are connected to the DC / DC conversion circuit #1 and the DC / DC conversion circuit #2 respectively. Fig.12 In the example, K51, K52, K59 and K510 are positive switches, and K53 to K58 are negative switches; Fig.12 As shown in , the negative pole switches K53 to K58 correspond to two connected photovoltaic units respectively, and their positive poles are connected to the DC / DC conversion circuit #1 and the DC / DC conversion circuit #2 respectively. Fig.13 In the example, K61 and K68 are positive switches, and K62 to K67 are negative switches; Fig.13 As shown in , the negative pole switches K62 to K67 correspond to two connected photovoltaic units respectively, and their positive poles are connected to the DC / DC conversion circuit #1 and the DC / DC conversion circuit #2 respectively. That is, when the negative poles of the DC power sources are connected, their positive poles are no longer connected and are connected to different DC / DC conversion circuits 10 respectively, so that it can not only ensure that there is no parallel connection relationship between the DC power sources, but also the number of DC / DC conversion circuits 10 with cross-connected DC power sources can be maximized.

[0125] In practical applications, in order to reduce the number of switches, as described in the above embodiments, the number of DC / DC conversion circuits with cross-connected DC power supplies can be increased as much as possible. For example, it can be configured that the negative poles of the DC power supplies connected to the positive poles of the input terminals of the DC / DC conversion circuits 10 are connected to the negative pole switches connected to the negative poles of the input terminals of the different DC / DC conversion circuits 10. For example, Fig.10 If a DC / DC conversion circuit #3 is added, the negative pole PV1- of the first photovoltaic unit PV1 may not need to add the negative pole switch K13', but can be connected to the negative pole switch of the DC / DC conversion circuit #3, and the negative pole switch K13' can be omitted.

[0126] Alternatively, the DC power supplies can be cross-connected between different DC / DC conversion circuits 10 as much as possible; for example, Fig.10 In the structure shown in FIG. 1 , the negative electrode PV1- of the first photovoltaic unit PV1 and the negative electrode PV6- of the sixth photovoltaic unit can also share the same negative electrode switch, that is, Fig.10 The negative switches K13' and K14' in Fig.14 The negative pole switch K134' shown in FIG. 1 can further reduce the number of switches.

[0127] That is, assuming that the number of DC / DC conversion circuits 10 is M, where M is an integer greater than 1, at least M+1 negative pole switches may be provided, each of which has a first side connected to at least two positive poles connected to a DC power supply of different DC / DC conversion circuits 10; for example Fig.11 For any one of the negative pole switches K44 to K47 shown in the figure, the positive poles of the DC power supplies connected to the first side thereof are respectively connected to different DC / DC conversion circuits 10, namely, DC / DC conversion circuit #1 and DC / DC conversion circuit #2. At this time, M DC / DC conversion circuits 10 can share at least M+1 negative pole switches, and the more the number of shared negative pole switches is, the more the number of negative pole switches that can be reduced is.

[0128] In one example, the first sides of all negative switches may be respectively connected to at least two positive DC power supplies connected to different DC / DC conversion circuits 10; for example Fig.12 Negative switches K53 to K58 in, or Fig.13 The negative pole switches K62 to K67 in the figure, wherein the positive poles of the DC power sources connected to the first side of each negative pole switch are respectively connected to different DC / DC conversion circuits 10, namely, DC / DC conversion circuit #1 and DC / DC conversion circuit #2.

[0129] That is, in Figure 6 On the basis of Fig.10The structure shown can make each switch withstand up to 2 times the DC power supply voltage when a DC power supply reverse connection fault occurs. Fig.14 This further reduces the number of switches used. Fig.11 The negative switches K43 and K48 in the circuit can also be combined into one, and can also be used in Fig.11 On the basis of this, one more negative switch is added.

[0130] In addition, since the negative electrode of the output end of each DC / DC conversion circuit 10 is connected to the negative electrode BUS- of the DC bus, the negative electrode of the input end of each DC / DC conversion circuit 10 can also be connected under the common negative electrode topology; that is, the second sides of each negative electrode switch are connected, and the equipoints after the second sides of each negative electrode switch are connected are respectively connected to the negative electrode of the input end of different DC / DC conversion circuits 10. Fig.11 As shown in , the second sides of the negative switches K43 to K48 are connected, and the voltage at any position after the connection is equal, which can be called an equipoint; that is, the negative electrode of the input end of each DC / DC conversion circuit 10 can be connected to any position after the negative switches K43 to K48 are connected, as long as the second side of each negative switch K43 to K48 is connected to the negative electrode of the input end of the two DC / DC conversion circuits. Fig.12 As shown in , the second side of each negative electrode switch K53 to K58 and the negative electrode of the input end of the two DC / DC conversion circuits are connected. Fig.13 As shown in , the second side of each negative switch K62 to K67 and the negative input terminals of the two DC / DC conversion circuits are connected. With this connection relationship, the corresponding ports of the devices involved can be connected nearby, which is convenient for wiring.

[0131] Furthermore, under the above settings, the positive pole of the input terminal of any DC / DC conversion circuit 10 can be connected to the corresponding DC power supplies through at least one positive switch. For each DC power supply connected to the positive pole of the input terminal of each DC / DC conversion circuit 10, since their negative poles will be connected to different negative switches respectively, even if there are connection points between their positive poles, they will not be connected in parallel with each other; at this time, the positive pole of the input terminal of the DC / DC conversion circuit 10 only needs to have one positive pole switch to ensure that the positive pole disconnection function can be realized; of course, the positive pole of the input terminal of the DC / DC conversion circuit 10 can also be provided with two or more positive pole switches, which can be determined according to the number of DC power supplies it is connected to, and is not limited here. Fig.11 , Fig.12 and Fig.14 As shown in , the positive input terminal of each DC / DC conversion circuit 10 is connected to two positive switches respectively; Fig.13 As shown in FIG. 1 , the positive input terminal of each DC / DC conversion circuit 10 is respectively connected to a positive switch.

[0132] Figures 11 to 14 The example of the inverter with the number M=2 of DC / DC conversion circuits 10 is used to show different structures. The number of switches and the number of photovoltaic units may also adopt other values ​​and are not shown one by one. The situation when M>2 can be deduced similarly and is not shown again.

[0133] Similarly, when the DC / DC conversion circuit 10 is a common positive pole topology, its principle is the same as the above content, that is, it can also be set that: the positive poles of the DC power supplies connected to the negative poles of the input end of each DC / DC conversion circuit 10 are respectively connected to different positive pole switches. Under this setting, when the number of DC power supplies connected to the positive pole switches is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits 10 through the corresponding negative pole switches. Furthermore, in order to further reduce the number of switches, it can be set that: when the number of DC / DC conversion circuits 10 is M, there are at least M+1 positive pole switches, each of which has a first side connected to at least two DC power supplies with negative poles connected to different DC / DC conversion circuits 10; it can also be set that: the positive poles of the DC power supplies connected to the negative poles of the input end of the DC / DC conversion circuit 10 are respectively connected to different DC / DC conversion circuits 10 through corresponding positive pole switches. In addition, the second sides of the positive pole switches are connected, and the equipotential points after connection are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits 10. Furthermore, the negative input terminal of any DC / DC conversion circuit 10 is connected to the corresponding DC power source through at least one negative switch.

[0134] This embodiment can not only avoid the parallel connection between the DC power supplies to avoid the reverse current, but also avoid the problem that two switches bear three times the DC power supply voltage after the switches are disconnected; in addition, the number of DC / DC conversion circuits with cross-connected DC power supplies can be increased as much as possible, or the number of cross-connected DC power supplies between different DC / DC conversion circuits 10 can be increased as much as possible, so as to share more switches, thereby further reducing the number of switches.

[0135] Based on the above embodiment, this embodiment provides some examples of implementation forms of the switches in the inverter, such as:

[0136] The switches in the inverter can be grouped and integrated into different linkage switches; a group of switches set in the same linkage switch will act at the same time, that is, they will maintain the same open and break state. The number of linkage switches used in the inverter and how the switches are grouped can be determined according to actual application requirements and are not limited here.

[0137] Alternatively, all switches in the inverter may be integrated into the same linkage switch, thereby saving the structural cost of the inverter.

[0138] In addition, in practical applications, each switch in the inverter can be disconnected and controlled manually, or by a controller. The controller can be a controller in the inverter (such as Figure 1 30 shown in ); or, the controller may also refer to other controllers such as a host computer, which is not limited here.

[0139] The above linkage switch can be a rotary DC switch, see Fig.15 , the knob 103, the connecting rod 102 and the P-stage linkage switch 101 are arranged along the first direction, wherein the knob 103 is connected to the connecting rod 102 and can be used to drive the connecting rod 102 to rotate; the connecting rod 102 is used to connect the knob 103 and the P-stage linkage switch 101. The P-stage linkage switch 101 includes a first-stage switch 111, a second-stage switch 112, ..., and a P-stage switch 11P, where P is an integer greater than or equal to 1; each stage switch can be used as a switch described in the above embodiment, and two pins are arranged on it to realize the connection of the DC power supply and the DC / DC conversion circuit 10 on both sides thereof; specifically, one pin can be arranged to connect the positive or negative pole of the DC power supply, and another pin can be arranged to connect the corresponding pole of the input end of the DC / DC conversion circuit 10. The P switches are stacked along the first direction, and when the connecting rod 102 rotates, the P switches are linked to close or disconnect, so as to realize the connection or disconnection between the DC power supply and the DC / DC conversion circuit.

[0140] In practical applications, the linkage switch may also use other structures. Fig.15 This is only an optional example and is not limited thereto. In addition, solutions in which each switch is independent of each other are also within the protection scope of this application.

[0141] Another embodiment of the present application further provides a combiner box, see Figure 1 , Figure 2 , Figures 6 to 14 , comprising: a controller 30, at least two DC / DC conversion circuits 10, at least two positive switches and at least two negative switches; wherein:

[0142] The first side of each positive switch is used as the positive input terminal of the combiner box, and is used to connect the positive pole of the corresponding at least one DC power supply; the second side of each positive switch is connected to the positive input terminal of the corresponding DC / DC conversion circuit 10. The first side of each negative switch is used as the negative input terminal of the combiner box, and is used to connect the negative pole of the corresponding at least one DC power supply; the second side of each negative switch is connected to the negative input terminal of the corresponding DC / DC conversion circuit 10. As described in the above embodiments, the DC power supply can refer to a photovoltaic unit or an energy storage unit, which is not limited here.

[0143] The number of the same DC power supplies connected to any positive switch and any negative switch is less than 2, so that after the switch is disconnected, there is no parallel connection relationship between the DC power supplies.

[0144] Furthermore, there is at least one positive switch or negative switch, the number of DC power supplies connected to it is greater than 1, and the other pole of at least one DC power supply in each corresponding DC power supply is connected to the switch connected to the corresponding pole of the input end of another DC / DC conversion circuit 10; that is, the arrangement is such that there are cross-connected DC power supplies between different DC / DC conversion circuits 10 to reduce the number of switches used.

[0145] The output end of the DC / DC conversion circuit 10 is used as the output end of the combiner box; in practical applications, the output ends of each DC / DC conversion circuit 10 can be connected in parallel to the output end of the combiner box, and then connected to the power grid and / or load through the subsequent DC / AC conversion circuit 20. That is, different from the above embodiment, for Figure 1 , Figure 2 , Figures 6 to 14 In the structure shown, the DC / AC conversion circuit 20 can be regarded as the main circuit in the centralized inverter, and its DC side can be connected to the output end of at least one combiner box; for example, the DC side of the centralized inverter can be connected to the output ends of multiple combiner boxes through a DC bus. In this case, the combiner box can also be called an intelligent combiner box because it integrates the DC / DC conversion circuit 10.

[0146] In practical applications, the DC / DC conversion circuit 10 has a variety of optional topologies; for example, when the DC power supply is a photovoltaic unit, the DC / DC conversion circuit 10 can use a Boost circuit, a Buck circuit, a Buck-Boost circuit, etc.; and when the DC power supply is an energy storage unit, the DC / DC conversion circuit 10 can use a bidirectional Buck-Boost circuit, a bidirectional Boost-Buck circuit, a bidirectional Cuk circuit, a bidirectional Sepic-Zeta circuit, a bidirectional two-bridge arm Buck-Boost circuit, a three-phase staggered parallel DC-DC conversion topology, a phase-shifted full-bridge topology, a full-bridge isolated voltage source topology, a full-bridge isolated current source topology, etc.; the specific structure of each circuit can refer to the prior art, and will not be repeated here. The topology selection of the DC / DC conversion circuit 10 depends on its specific application environment, and is within the protection scope of this application. The signal input end of each DC / DC conversion circuit 10, the signal input end of each positive switch, and the signal input end of each negative switch are respectively connected to the controller 30 to receive the control signal sent by the controller 30.

[0147] Each DC / DC conversion circuit 10, each positive switch and each negative switch are respectively controlled by a controller 30. That is, the controller 30 can control the on and off of each switch, and can also control the operating state of each DC / DC conversion circuit 10; the specific control principle can be referred to the prior art, and will not be described here.

[0148] Specifically, when the DC / DC conversion circuit 10 is a common negative pole topology, for the positive pole switch, if the number of DC power supplies connected to it is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to different negative pole switches; when the DC / DC conversion circuit 10 is a common positive pole topology, for the negative pole switch, if the number of DC power supplies connected to it is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to different positive pole switches.

[0149] In addition, when the first side of a positive switch is connected to a DC power supply, the negative pole of the corresponding DC power supply is connected to the first side of any negative switch; when the first side of a negative switch is connected to a DC power supply, the positive pole of the corresponding DC power supply is connected to the first side of any positive switch.

[0150] In one example, there is at least one switch connected to a DC power source whose number is greater than 1, and the other poles of the corresponding DC power sources are connected to different DC / DC conversion circuits 10 through corresponding switches to save as many switches as possible.

[0151] In order to avoid the problem of two switches bearing three times the DC power supply voltage after the switches are disconnected, the following settings can be made: the negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit 10 are connected to different negative pole switches; or, the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit 10 are connected to different positive pole switches.

[0152] In one example, it can be configured that: the negative poles of each DC power supply connected to the positive pole of the input end of the DC / DC conversion circuit 10 are respectively connected to different negative pole switches; and the positive poles of each DC power supply connected to the negative pole of the input end of the DC / DC conversion circuit 10 are respectively connected to different positive pole switches.

[0153] Specifically, when the DC / DC conversion circuit 10 is a common negative pole topology, the negative poles of each DC power supply connected to the positive pole of the input end of the DC / DC conversion circuit 10 are connected to different negative pole switches; when the DC / DC conversion circuit 10 is a common positive pole topology, the positive poles of each DC power supply connected to the negative pole of the input end of the DC / DC conversion circuit 10 are connected to different positive pole switches.

[0154] In practical applications, when the DC / DC conversion circuit 10 is a common negative pole topology, when the number of DC power supplies connected to the negative pole switch is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits 10 through the corresponding positive pole switches; when the DC / DC conversion circuit 10 is a common positive pole topology, when the number of DC power supplies connected to the positive pole switch is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits 10 through the corresponding negative pole switches.

[0155] In one example, when the number of DC / DC conversion circuits 10 is M and all of them are in a common negative pole topology, M is an integer greater than 1, and there are at least M+1 negative pole switches, wherein the first side of each negative pole switch is connected to at least two DC power supplies, and the positive poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits 10; when the number of DC / DC conversion circuits 10 is M and all of them are in a common positive pole topology, M is an integer greater than 1, and there are at least M+1 positive pole switches, wherein the first side of each positive pole switch is connected to at least two DC power supplies, and the negative poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits 10. This setting can make the cross-connection of DC power supplies between different DC / DC conversion circuits 10 as much as possible to reduce the number of switches.

[0156] In one example, when the DC / DC conversion circuit 10 is a common negative pole topology, the positive pole of the input end of the DC / DC conversion circuit 10, and the negative poles of each DC power supply connected thereto are connected to different DC / DC conversion circuits 10 through corresponding negative pole switches; when the DC / DC conversion circuit 10 is a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit 10, and the positive poles of each DC power supply connected thereto are connected to different DC / DC conversion circuits 10 through corresponding positive pole switches. This setting can maximize the number of DC / DC conversion circuits with cross-connected DC power supplies, and can also reduce the number of switches.

[0157] In one example, when the DC / DC conversion circuit 10 is a common negative pole topology, the positive pole of the input end of the DC / DC conversion circuit 10 is connected to the corresponding DC power supplies through at least one positive pole switch; when the DC / DC conversion circuit 10 is a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit 10 is connected to the corresponding DC power supplies through at least one negative pole switch. That is, there is no limit on the number of switches of the other pole of the common negative pole topology or the common positive pole topology, as long as there is one switch, it can ensure that the pole can realize the disconnection function; of course, the pole can also be provided with a larger number of switches, all within the protection scope of this application.

[0158] In one example, when the DC / DC conversion circuit 10 is in a common negative electrode topology, the second sides of the negative electrode switches are connected, and after being connected, they are respectively connected to the negative electrodes of the input terminals of different DC / DC conversion circuits 10; when the DC / DC conversion circuit 10 is in a common positive electrode topology, the second sides of the positive electrode switches are connected, and after being connected, they are respectively connected to the positive electrodes of the input terminals of different DC / DC conversion circuits 10. With this connection relationship, the corresponding ports of the devices involved can be connected nearby, which is convenient for wiring.

[0159] In one example, after the switch is turned off, there is no parallel connection relationship between any two DC power supplies.

[0160] In one example, the switches are grouped and integrated into different linkage switches, or all the switches are integrated into the same linkage switch.

[0161] In one example, each switch is disconnected and controlled manually or by a controller.

[0162] The working principles of the switches and the DC / DC conversion circuits 10 in the combiner box can be found in the above embodiments, and will not be described in detail here.

[0163] The junction box provided in this embodiment can avoid the existence of a parallel connection relationship between the DC power supplies after the switch is disconnected through the above-mentioned structural setting. Furthermore, when the DC power supply is reversely connected, there will be no reverse current after the switch is disconnected. The connection between the reverse DC power supply and the switches on both sides can be directly disconnected, and no arcing will occur, and there is no risk of electric shock or fire. Moreover, by cross-connecting the DC power supplies between different DC / DC conversion circuits, the number of switches used can be reduced. In addition, by allocating the positive and negative poles of each DC power supply connected to each DC / DC conversion circuit 10, it is also possible to avoid the situation where two switches are subjected to 3 times the DC power supply voltage. Furthermore, by sharing the corresponding switch at the negative pole of the input end or the positive pole of the input end of the DC / DC conversion circuit 10, the number of switches can be further reduced.

[0164] in addition, Figure 1 , Figure 2 , Figures 6 to 14 In the figure, the DC side of the DC / AC conversion circuit 20 is connected to two DC / DC conversion circuits 10 as an example for demonstration, except that the number of switches is different, or the connection method between each DC / DC conversion circuit 10 and the switch is different; in actual application, the number of each device in the junction box and the number of DC power supplies connected to it can be determined according to the application environment, and the specific connection structure can also have various forms, which are no longer shown one by one.

[0165] It is worth noting that the naming of the input and output ends of each device in this application is only to distinguish between the two sides, and does not limit the direction of its power transmission. For example, when the DC power supply is an energy storage unit, its discharge process will cause the electric energy to be transmitted to the power grid and / or load through the corresponding DC / DC conversion circuit 10 and the DC / AC conversion circuit 20 in sequence, or to be transmitted to the DC bus through the corresponding DC / DC conversion circuit 10 and then supply power to the DC load; and its charging process will cause the electric energy to be charged from the power grid in reverse through the DC / AC conversion circuit 20 and the corresponding DC / DC conversion circuit 10, or to be charged from other power sources through the DC bus in reverse through the corresponding DC / DC conversion circuit 10.

[0166] The same and similar parts between the various embodiments in this specification can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are only schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative work.

[0167] For the above description of the disclosed embodiments, the features described in the embodiments in this specification may be replaced or combined with each other, so that professionals in the field can implement or use the present application. Various modifications to these embodiments will be obvious to professionals in the field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An inverter, characterized in that: include: A controller, a DC / AC conversion circuit, at least two DC / DC conversion circuits, at least two positive switches and at least two negative switches; wherein, The first side of each of the positive switches is connected to the positive electrode of at least one corresponding DC power supply; the second side of each of the positive switches is connected to the positive electrode of the input end of the corresponding DC / DC conversion circuit; The first side of each of the negative switches is connected to the negative electrode of at least one of the DC power supplies; the second side of each of the negative switches is connected to the negative electrode of the input terminal of the DC / DC conversion circuit; The number of the same DC power sources connected to any of the positive switches and any of the negative switches is less than 2; There is at least one of the positive switch or the negative switch, the number of the DC power supplies connected to it is greater than 1, and there is at least one switch connected to the corresponding pole of the DC power supply in each of the DC power supplies; The output end of the DC / DC conversion circuit is connected to the DC side of the DC / AC conversion circuit; The AC side of the DC / AC conversion circuit serves as the output end of the inverter; The DC / AC conversion circuit, each of the DC / DC conversion circuits, each of the positive switches and each of the negative switches are respectively controlled by the controller.

2. The inverter according to claim 1, characterized in that: When the DC / DC conversion circuit is a common cathode topology, for the positive electrode switch, if the number of the DC power supplies connected to it is greater than 1, the negative electrodes of the corresponding DC power supplies are respectively connected to different negative electrode switches; When the DC / DC conversion circuit is a common positive pole topology, for the negative pole switch, if the number of the DC power supplies connected to it is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to different positive pole switches.

3. The inverter according to claim 1, characterized in that: When the first side of the positive switch is connected to one of the DC power supplies, the negative pole of the corresponding DC power supply is connected to the first side of any of the negative switches; When the first side of the negative pole switch is connected to one of the DC power sources, the positive pole of the corresponding DC power source is connected to the first side of any of the positive pole switches.

4. The inverter according to claim 1, characterized in that: There is at least one switch connected to a number of DC power supplies greater than 1, and the other poles of the corresponding DC power supplies are connected to different DC / DC conversion circuits through corresponding switches.

5. The inverter according to claim 1, characterized in that: The negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; or, the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

6. The inverter according to claim 1, characterized in that: The negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; and the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

7. The inverter according to claim 1, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the cathodes of the DC power supplies connected to the positive electrodes of the input terminals of the DC / DC conversion circuit are respectively connected to different cathode switches; When the DC / DC conversion circuit is of a common positive pole topology, the positive poles of the DC power supplies connected to the negative poles of the input terminals of the DC / DC conversion circuit are respectively connected to different positive pole switches.

8. The inverter according to claim 7, characterized in that: When the DC / DC conversion circuit is a common cathode topology, when the number of the DC power supplies connected to the cathode switch is greater than 1, the positive electrodes of the corresponding DC power supplies are connected to the positive electrodes of the input terminals of different DC / DC conversion circuits through the corresponding positive switches; When the DC / DC conversion circuit is a common positive pole topology, when the number of the DC power supplies connected to the positive pole switch is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits through the corresponding negative pole switches.

9. The inverter according to claim 7, characterized in that: When the number of the DC / DC conversion circuits is M and all of them are common negative pole topology, M is an integer greater than 1, and there are at least M+1 negative pole switches, wherein the first side of each of the negative pole switches is connected to at least two DC power supplies, and the positive poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits; When the number of the DC / DC conversion circuits is M and all are common positive pole topologies, M is an integer greater than 1, and there are at least M+1 positive pole switches, wherein the first side of each of the positive pole switches is connected to at least two DC power supplies, and the negative poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits.

10. The inverter according to claim 7, characterized in that: When the DC / DC conversion circuit is of a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the negative electrodes of the DC power supplies and connected to different DC / DC conversion circuits through the corresponding negative electrode switches; When the DC / DC conversion circuit is of a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit is connected to the positive poles of the DC power supplies and is connected to different DC / DC conversion circuits through corresponding positive pole switches.

11. The inverter according to claim 7, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one positive switch; When the DC / DC conversion circuit is in a common positive pole topology, the negative pole of the input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one negative pole switch.

12. The inverter according to claim 7, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the second sides of the cathode switches are connected, and after being connected, they are respectively connected to the cathodes of the input terminals of different DC / DC conversion circuits; When the DC / DC conversion circuit is of a common positive pole topology, the second sides of the positive pole switches are connected to each other, and after being connected, they are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits.

13. The inverter according to any one of claims 1 to 12, characterized in that: After the switch is turned off, there is no parallel connection relationship between any two of the DC power supplies.

14. The inverter according to any one of claims 1 to 12, characterized in that: The switches are grouped and integrated into different linkage switches, or all the switches are integrated into the same linkage switch.

15. The inverter according to any one of claims 1 to 12, characterized in that: Each switch is disconnected and controlled manually or by a controller.

16. A combiner box, characterized in that: include: A controller, at least two DC / DC conversion circuits, at least two positive switches and at least two negative switches; wherein, The first side of each of the positive switches is respectively used as the positive input terminal of the combiner box, and is used to connect the positive electrode of at least one corresponding DC power supply; the second side of each of the positive switches is respectively connected to the positive input terminal of the corresponding DC / DC conversion circuit; The first side of each of the negative switches is respectively used as the negative input terminal of the combiner box, and is used to connect the negative electrode of at least one of the DC power supplies; the second side of each of the negative switches is respectively connected to the negative electrode of the input terminal of the corresponding DC / DC conversion circuit; The number of the same DC power sources connected to any of the positive switches and any of the negative switches is less than 2; There is at least one of the positive switch or the negative switch, the number of the DC power supplies connected to it is greater than 1, and there is at least one switch connected to the corresponding pole of the DC power supply in each of the DC power supplies; The output end of the DC / DC conversion circuit serves as the output end of the combiner box; Each of the DC / DC conversion circuits, each of the positive switches and each of the negative switches are controlled by the controller respectively.

17. The combiner box according to claim 16, characterized in that: When the DC / DC conversion circuit is a common cathode topology, for the positive electrode switch, if the number of the DC power supplies connected to it is greater than 1, the negative electrodes of the corresponding DC power supplies are respectively connected to different negative electrode switches; When the DC / DC conversion circuit is a common positive pole topology, for the negative pole switch, if the number of the DC power supplies connected to it is greater than 1, the positive poles of the corresponding DC power supplies are respectively connected to different positive pole switches.

18. The combiner box according to claim 16, characterized in that: When the first side of the positive switch is connected to one of the DC power supplies, the negative pole of the corresponding DC power supply is connected to the first side of any of the negative switches; When the first side of the negative pole switch is connected to one of the DC power sources, the positive pole of the corresponding DC power source is connected to the first side of any of the positive pole switches.

19. The combiner box according to claim 16, characterized in that: There is at least one switch connected to a number of DC power supplies greater than 1, and the other poles of the corresponding DC power supplies are connected to different DC / DC conversion circuits through corresponding switches.

20. The combiner box according to claim 16, characterized in that: The negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; or, the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

21. The combiner box according to claim 16, characterized in that: The negative poles of the DC power supplies connected to the positive pole of the input end of the DC / DC conversion circuit are respectively connected to different negative pole switches; and the positive poles of the DC power supplies connected to the negative pole of the input end of the DC / DC conversion circuit are respectively connected to different positive pole switches.

22. The combiner box according to claim 16, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the cathodes of the DC power supplies connected to the positive electrodes of the input terminals of the DC / DC conversion circuit are respectively connected to different cathode switches; When the DC / DC conversion circuit is of a common positive pole topology, the positive poles of the DC power supplies connected to the negative poles of the input terminals of the DC / DC conversion circuit are respectively connected to different positive pole switches.

23. The combiner box according to claim 22, characterized in that: When the DC / DC conversion circuit is a common cathode topology, when the number of the DC power supplies connected to the cathode switch is greater than 1, the positive electrodes of the corresponding DC power supplies are connected to the positive electrodes of the input terminals of different DC / DC conversion circuits through the corresponding positive switches; When the DC / DC conversion circuit is a common positive pole topology, when the number of the DC power supplies connected to the positive pole switch is greater than 1, the negative poles of the corresponding DC power supplies are respectively connected to the negative poles of the input ends of different DC / DC conversion circuits through the corresponding negative pole switches.

24. The combiner box according to claim 22, characterized in that: When the number of the DC / DC conversion circuits is M and all of them are common negative pole topology, M is an integer greater than 1, and there are at least M+1 negative pole switches, wherein the first side of each of the negative pole switches is connected to at least two DC power supplies, and the positive poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits; When the number of the DC / DC conversion circuits is M and all are common positive pole topologies, M is an integer greater than 1, and there are at least M+1 positive pole switches, wherein the first side of each of the positive pole switches is connected to at least two DC power supplies, and the negative poles of the corresponding DC power supplies are respectively connected to different DC / DC conversion circuits.

25. The combiner box according to claim 22, characterized in that: When the DC / DC conversion circuit is of a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the negative electrodes of the DC power supplies and connected to different DC / DC conversion circuits through the corresponding negative electrode switches; When the DC / DC conversion circuit is of a common positive pole topology, the negative pole of the input end of the DC / DC conversion circuit is connected to the positive poles of the DC power supplies and is connected to different DC / DC conversion circuits through corresponding positive pole switches.

26. The combiner box according to claim 22, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the positive input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one positive switch; When the DC / DC conversion circuit is in a common positive pole topology, the negative pole of the input terminal of the DC / DC conversion circuit is connected to the corresponding DC power supply through at least one negative pole switch.

27. The combiner box according to claim 22, characterized in that: When the DC / DC conversion circuit is a common cathode topology, the second sides of the cathode switches are connected, and after being connected, they are respectively connected to the cathodes of the input terminals of different DC / DC conversion circuits; When the DC / DC conversion circuit is of a common positive pole topology, the second sides of the positive pole switches are connected to each other, and after being connected, they are respectively connected to the positive poles of the input ends of different DC / DC conversion circuits.

28. The combiner box according to any one of claims 16 to 27, characterized in that: After the switch is turned off, there is no parallel connection relationship between any two of the DC power supplies.

29. The combiner box according to any one of claims 16 to 27, characterized in that: The switches are grouped and integrated into different linkage switches, or all the switches are integrated into the same linkage switch.

30. The combiner box according to any one of claims 16 to 27, characterized in that: Each switch is disconnected and controlled manually or by a controller.

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