Converter, control method of converter, and microgrid system

Abstract

The application provides a converter, a control method and system of the converter, and relates to the technical field of micro-grid. The converter comprises a multiphase alternating current interface, a first filter, a full-bridge circuit, a half-bridge circuit, a capacitor module and a direct current interface; the multiphase alternating current interface, the first filter, the full-bridge circuit, the half-bridge circuit, the capacitor module and the direct current interface are sequentially connected; wherein the multiphase alternating current interface is used for being connected with a multiphase alternating current distribution interface in an alternating current distribution interface, and the alternating current distribution interface is used for providing alternating current; the converter further comprises a first interface connected with the first filter, a second interface connected with the bridge arm output end of the half-bridge circuit and the capacitor module, and a third interface connected with the bridge arm output end of the half-bridge circuit; the first interface, the second interface and the third interface are selectively connected with a target phase interface in the alternating current distribution interface, so as to change the type of the converter. The structure of the converter is convenient for users to select and use different types of converters, and the user experience is improved.

Description

Technical Field

[0001] This invention relates to the field of microgrid technology, and more specifically, to a converter, a control method for the converter, and a microgrid system. Background Technology

[0002] Significant changes have occurred in the new power system, characterized by a shift from traditional energy consumption patterns towards cleaner power generation, electrified transportation, and more flexible production and consumption. Regarding the flexibility of production and consumption, power electronic conversion devices are often needed to realize various application scenarios; therefore, converters have become a research hotspot.

[0003] In related technologies, there are many types of converters, and converters of different specifications have different functions. Different types of converters can be selected according to actual needs.

[0004] However, in related technologies, converters with different rules are independent of each other, which makes it inconvenient for users to choose and use them. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a converter, a control method for the converter, and a microgrid system, so as to solve the aforementioned technical problems in the related technologies.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0007] In a first aspect, embodiments of the present invention provide a converter, including: a multiphase AC interface, a first filter, a full-bridge circuit, a half-bridge circuit, a capacitor module, and a DC interface;

[0008] The multiphase AC interface, the first filter, the full-bridge circuit, the half-bridge circuit, the capacitor module, and the DC interface are connected in sequence; wherein, the multiphase AC interface is used to connect to the multiphase AC distribution interface in the AC distribution interface, and the AC distribution interface is used to provide AC power;

[0009] The converter further includes: a first interface connected to the first filter, a second interface connected to both the bridge arm output terminal of the half-bridge circuit and the capacitor module, and a third interface connected to the bridge arm output terminal of the half-bridge circuit; the first interface, the second interface, and the third interface are selectively connected to target phase interfaces in the AC power distribution interface to change the type of the converter.

[0010] Optionally, the converter further includes an AC interface; the first interface, the second interface, the third interface, and the multiphase AC interface are integrated in the AC interface, and the AC interface is located near the AC distribution interface.

[0011] Optionally, the converter is a first type of converter, and the first interface, the second interface, and the third interface are connected in sequence, with the third interface connected to the target phase interface;

[0012] Alternatively, the converter is a second type of converter, with the first interface and the second interface connected to each other, and the third interface connected to the target phase interface;

[0013] Alternatively, the converter may be a third type of converter, in which the first interface, the second interface, and the third interface are not connected to each other, and the third interface is not connected to the target phase interface.

[0014] Optionally, the first interface, the second interface, and the third interface can be selectively connected to the target phase interface in the AC power distribution interface through different wiring combinations to change the type of the converter.

[0015] Optionally, the converter further includes: a first switching device, a second switching device, and a third switching device;

[0016] The first switching device is disposed between the first interface and the second interface, the second switching device is disposed between the second interface and the third interface, and the third switching device is disposed between the third interface and the target phase interface;

[0017] Specifically, by changing the switching states of the first switching device, the second switching device, and the third switching device, the first interface, the second interface, and the third interface are controlled to selectively connect to the target phase interface in the AC power distribution interface, thereby changing the type of the converter.

[0018] Optionally, the converter further includes: a second filter;

[0019] The second filter is connected to the bridge arm output terminal of the half-bridge circuit, and the second interface is an interface that is connected to both the first terminal of the second filter and the capacitor module; the third interface is an interface that is connected to the second terminal of the second filter.

[0020] Optionally, the first filter is a three-phase filter, the full-bridge circuit is a three-phase full-bridge circuit, and the first interface is an interface connected to the midpoint of the capacitor of the three-phase filter.

[0021] The second filter includes a first capacitor and at least two first inductors connected in sequence. One end of the first capacitor is connected between the at least two first inductors, and the other end of the first capacitor is the first end of the second filter. The second end of the second filter is one end of the first of the at least two first inductors, and one end of the last of the at least two first inductors is connected to the bridge arm output of the half-bridge circuit.

[0022] Optionally, the first filter includes multiple sets of devices, each set of devices including: a second capacitor and at least two second inductors connected in sequence;

[0023] One end of the second capacitor is connected between the at least two second inductors, and the first interface is an interface connected to the other end of the second capacitor;

[0024] One end of the first second inductor of the at least two second inductors in each group of devices is connected to the multiphase AC interface, and one end of the last second inductor of the at least two second inductors in each group of devices is connected to the full-bridge circuit.

[0025] Secondly, embodiments of the present invention also provide a control method for a converter, applied to the converter described in the first aspect, the method comprising:

[0026] In response to input selection operation for converter type, determine the target type converter from multiple preset converter types;

[0027] A control command corresponding to the target type of converter is sent to the converter so that the converter changes the switching state of the first switching device, the second switching device, and the third switching device according to the control command, thereby switching the converter to the target type of converter.

[0028] Thirdly, embodiments of the present invention also provide a microgrid system, including the converter described in the first aspect.

[0029] The beneficial effects of this invention are as follows: This application provides a converter, including: a multi-phase AC interface, a first filter, a full-bridge circuit, a half-bridge circuit, a capacitor module, and a DC interface; the multi-phase AC interface, the first filter, the full-bridge circuit, the half-bridge circuit, the capacitor module, and the DC interface are connected sequentially; wherein, the multi-phase AC interface is used to connect to a multi-phase AC distribution interface in an AC distribution interface, and the AC distribution interface is used to provide AC power; the converter further includes: a first interface connected to the first filter, a second interface connected to both the bridge arm output terminal of the half-bridge circuit and the capacitor module, and a third interface connected to the bridge arm output terminal of the half-bridge circuit; the first interface, the second interface, and the third interface are selectively connected to target phase interfaces in the AC distribution interface to change the type of the converter. By selectively connecting the first interface, the second interface, and the third interface to target phase interfaces in the AC distribution interface, the type of converter can be changed, enabling flexible switching of converter types. The structure of this converter facilitates user selection and use of different types of converters, improving the user experience. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the internal structure of a three-phase half-bridge converter provided in an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of the connection structure of a three-phase half-bridge converter provided in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the internal structure of a three-phase four-arm converter provided in an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the connection structure of a three-phase four-arm converter provided in an embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the internal structure of a three-phase full-bridge converter provided in an embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the connection structure of a three-phase full-bridge converter provided in an embodiment of the present invention;

[0040] Figure 10 This invention provides a schematic diagram of the connection structure of switching devices for a three-phase half-bridge converter.

[0041] Figure 11 This is a flowchart illustrating a converter control method provided in an embodiment of the present invention. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0043] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0044] In the description of this application, it should be noted that if the terms "upper", "lower", etc. appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in, it is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] Furthermore, the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0047] In related technologies, there are many types of converters, and different specifications of converters have different functions. Different types of converters can be selected according to actual needs. However, in related technologies, converters of different specifications are independent of each other, which is inconvenient for users to select and use.

[0048] To address the aforementioned technical problems in related technologies, this application provides a converter comprising: a multi-phase AC interface, a first interface connected to a first filter, a second interface connected to both the bridge arm output terminal of a half-bridge circuit and a capacitor module, and a third interface connected to the bridge arm output terminal of the half-bridge circuit. By selectively connecting the first, second, and third interfaces to target phase interfaces in the AC power distribution interface, the type of converter can be changed, enabling flexible switching of converter types. The structure of this converter facilitates user selection and use of different types of converters, improving the user experience.

[0049] Figure 1 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the converter may include: a multiphase AC interface 101, a first filter 11, a full-bridge circuit 12, a half-bridge circuit 14, a capacitor module 15, and a DC interface 16.

[0050] Among them, the multiphase AC interface 101, the first filter 11, the full-bridge circuit 12, the half-bridge circuit 14, the capacitor module 15 and the DC interface 16 are connected in sequence. The multiphase AC interface 101 is used to connect to the multiphase AC distribution interface 171 in the AC distribution interface 17. The AC distribution interface 17 is used to provide AC power.

[0051] The converter also includes: a first interface 102 connected to the first filter 11, a second interface 103 connected to the bridge arm output terminal of the half-bridge circuit 14 and the capacitor module 15, and a third interface 104 connected to the bridge arm output terminal of the half-bridge circuit 14; the first interface 102, the second interface 103, and the third interface 104 are selectively connected to the target phase interface 172 in the AC power distribution interface 17 to change the type of the converter.

[0052] Different types of converters may have different functions, and users can choose according to their actual needs.

[0053] It should be noted that the multiphase AC interface 101, the first filter 11, the full-bridge circuit 12, the half-bridge circuit 14, the capacitor module 15, and the DC interface 16 are connected sequentially. This means that the multiphase AC interface 101 is connected to the first filter 11, the first filter 11 is connected to the full-bridge circuit 12, the full-bridge circuit 12 is connected to the half-bridge circuit 14, the half-bridge circuit 14 is connected to the capacitor module 15, and the capacitor module 15 is connected to the DC interface 16. The AC power distribution interface 17 provides AC power, which the converter converts to DC power, and outputs DC power through the DC interface 16.

[0054] In this embodiment of the application, the selective connection of the first interface 102, the second interface 103, and the third interface 104 to the target phase interface in the AC power distribution interface 17 refers to the selective connection between the first interface 102, the second interface 103, and the third interface 104, and the selective connection of any one of the first interface 102, the second interface 103, and the third interface 104 to the target phase interface in the AC power distribution interface 17.

[0055] It is worth noting that when the first interface 102, the second interface 103, and the third interface 104 are selectively connected to the target phase interface in the AC power distribution interface 17, any of the following methods can be used: connecting with different structural components, connecting with a switch, connecting with a connecting wire, etc. Of course, other methods can also be used for connection, and this application embodiment does not impose specific restrictions on this.

[0056] In summary, this application provides a converter, including: a multi-phase AC interface, a first filter, a full-bridge circuit, a half-bridge circuit, a capacitor module, and a DC interface; the multi-phase AC interface,

[0057] The first filter, full-bridge circuit, half-bridge circuit, capacitor module, and DC interface are connected sequentially. The multi-phase AC interface connects to the multi-phase AC distribution interface in the AC distribution interface, which provides AC power. The converter also includes: a first interface connected to the first filter; a second interface connected to both the bridge arm output of the half-bridge circuit and the capacitor module; and a third interface connected to the bridge arm output of the half-bridge circuit. The first, second, and third interfaces can be selectively connected to target phase interfaces in the AC distribution interface to change the converter type. This selective connection of the first, second, and third interfaces to target phase interfaces in the AC distribution interface allows for flexible switching of converter types. The converter's structure facilitates user selection and use of different types of converters, improving the user experience.

[0058] Optional, Figure 2 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention, as shown below. Figure 2As shown, the converter also includes: AC interface 10; first interface 102, second interface 103, third interface 104 and multi-phase AC interface 101 are integrated in AC interface 10, and AC interface 10 is located near AC distribution interface 17.

[0059] The AC interface 10 is used to connect to the AC distribution interface 17. The multi-phase AC interface 101 in the AC interface 10 is used to connect to the multi-phase AC distribution interface 171 in the AC distribution interface 17; the first interface 102, the second interface 103, and the third interface 104 in the AC interface 10 are selectively connected to the target phase interface 172 in the AC distribution interface 17.

[0060] Optional, such as Figure 2 As shown, the converter also includes: a second filter 13;

[0061] The second filter 13 is connected to the bridge arm output terminal of the half-bridge circuit 14. The second interface 103 is an interface that is connected to the first terminal of the second filter 13 and the capacitor module 15. The third interface 104 is an interface that is connected to the second terminal of the second filter.

[0062] Optionally, the first filter 11 is a three-phase filter, the full-bridge circuit 12 is a three-phase full-bridge circuit, and the first interface 102 is an interface connected to the midpoint of the capacitor of the three-phase filter.

[0063] The second filter 13 includes a first capacitor and at least two first inductors connected in sequence. One end of the first capacitor is connected between the at least two first inductors, and the other end of the first capacitor is the first end of the second filter. The second end of the second filter is one end of the first of the at least two first inductors, and one end of the last of the at least two first inductors is connected to the bridge arm output of the half-bridge circuit.

[0064] The second filter 13 can be an N-line filter, the half-bridge circuit 14 is an N-line half-bridge circuit 14, and the capacitor module 15 includes multiple bus capacitors connected in series.

[0065] In this embodiment, the three-phase filter can be an LCL filter (passive harmonic filter) or other types of midpoint filters with filter capacitors. The three-phase full-bridge circuit 12 can include a three-level circuit and a multi-level circuit. The N-line filter can be an LCL filter or other types of filters. The N-line half-bridge circuit 14 can include a three-level circuit and a multi-level circuit.

[0066] In some implementations, the multiphase AC interface 101 can be a three-phase AC interface, which may include A, B, and C. The AC power distribution interface 17 can be a three-phase three-wire AC power distribution interface, which may include UA, UB, and UC, or a three-phase four-wire AC power distribution interface, which may include UA, UB, UC, and UN. The first interface 102 can be represented as N_LC, the second interface 103 can be represented as N_BUS, and the third interface 104 can be represented as N_SN, which is the output of the N-line bridge arm. Among them, A, B, and C can be connected to UA, UB, and UC, while N_LC, N_BUS, N_SN, and UN are selectively connected.

[0067] Figure 3 This is a schematic diagram of the structure of a converter provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the alternating current may include: Ua, Ub, Uc, and at least two first inductors connected in sequence may include: first inductors L7 and L8, and a first capacitor C3; the first first inductor can be L7, and the last first inductor can be L8, as shown. Figure 7 As shown, one end of L7 is the second end of the second filter 13 and is connected to N_SN. The other end of C3 is the first end of the second filter 13 and is connected to N_BUS. N_BUS is also connected to the capacitor module 15. The capacitor module includes bus capacitors C1 and C2 connected in series, and N_BUS is connected between C1 and C2.

[0068] Of course, such as Figure 3 As shown, the first capacitor C3 can be connected between the first inductors L7 and L8 via resistor R1. The converter may also include a DC interface 16, which may include DC+ and DC-.

[0069] like Figure 3 As shown, the full-bridge circuit 12 may include: sub-modules IGBT (Insulated Gate Bipolar Transistor) 1, IGBT 2, IGBT 3, IGBT 4, IGBT 5, and IGBT 6; the half-bridge circuit 14 may include: sub-modules IGBTn+ and IGBTn-. It should be noted that the internal connection structures of each device, as well as the connection structures between each device, can be referenced... Figure 2 This will not be elaborated upon here.

[0070] Optionally, the first filter includes multiple sets of devices, each set of devices including: a second capacitor and at least two second inductors connected in sequence; one end of the second capacitor is connected between the at least two second inductors, and the first interface is an interface connected to the other end of the second capacitor; one end of the first second inductor of the at least two second inductors in each set of devices is connected to a multi-phase AC interface, and one end of the last second inductor of the at least two second inductors in each set of devices is connected to a full-bridge circuit.

[0071] The number of second capacitors can be one. In each group of devices, one end of the second capacitor is connected between at least two second inductors through a resistor. One second capacitor and one resistor in each group of devices form a resistor-capacitor circuit RC.

[0072] like Figure 3 As shown, the multiple sets of devices can be three sets of devices. One set of devices includes: second inductors L1 and L2, and resistor-capacitor circuit RC1; another set of devices includes: second inductors L3 and L4, and resistor-capacitor circuit RC2; and yet another set of devices includes: second inductors L3 and L4, and resistor-capacitor circuit RC3.

[0073] It should be noted that, in one set of devices, one end of the first second inductor L2 is connected to A in AC interface 10, and the second second inductor L1 is connected between IGBT1 and IGBT2 in the full-bridge circuit 12; in another set of devices, one end of the first second inductor L4 is connected to B in AC interface 10, and the second second inductor L3 is connected between IGBT3 and IGBT4 in the full-bridge circuit 12; in yet another set of devices, one end of the first second inductor L6 is connected to C in AC interface 10, and the second second inductor L5 is connected between IGBT5 and IGBT6 in the full-bridge circuit 12.

[0074] In addition, the other end of the resistor-capacitor circuit RC1, RC2, and RC3 forms the midpoint of the capacitor of the three-phase filter and is connected to N_LC.

[0075] Optionally, the converter is a first type of converter, with the first interface 102, the second interface 103, and the third interface 104 connected in sequence, and the third interface 104 connected to the target phase interface 172.

[0076] Alternatively, the converter is a second type of converter, with the first interface 102 and the second interface 103 connected together, and the third interface 104 connected to the target phase interface 172.

[0077] Alternatively, the converter is a third type of converter, where the first interface 102, the second interface 103, and the third interface 104 are not connected to each other, and the third interface 104 is also not connected to the target phase interface 172.

[0078] It should be noted that by changing the connection relationship between the first interface 102, the second interface 103, the third interface 104, and the target phase interface 172, the three types of converters—the first type, the second type, and the third type—can be switched.

[0079] Optionally, the first type of converter is a three-phase half-bridge converter, the second type of converter is a three-phase four-arm converter, and the third type of converter is a three-phase full-bridge converter.

[0080] Among them, the three-phase half-bridge converter can also be called the three-phase three-wire converter, and the three-phase full-bridge converter can also be called the three-phase four-wire converter.

[0081] In the embodiments of this application, the three-phase half-bridge converter can be applied to energy storage converters with pure active and reactive power control, the three-phase full-bridge converter is applied to distributed energy storage where additional three-phase unbalanced power needs to be added on the basis of the three-phase half-bridge converter, and the three-phase four-bridge converter is used in transformerless transformer substation interconnection systems. It suppresses the N-line circulating current problem between substations on the basis of the three-phase half-bridge converter and the three-phase full-bridge converter, and has the widest application range.

[0082] Among them, three-phase half-bridge converters, three-phase full-bridge converters, and three-phase four-arm converters each have their own advantages and disadvantages in terms of function and performance. Three-phase half-bridge converters have the widest DC voltage range and the best efficiency in terms of specifications, but can only control total active power and total reactive power. Three-phase full-bridge converters have a moderate DC voltage range and the best efficiency in terms of specifications, and can independently control the power of each phase. Three-phase four-arm converters have a moderate DC voltage range and a moderate efficiency of less than 0.5%, and can control the neutral line current.

[0083] Optionally, the first interface 102, the second interface 103, and the third interface 104 can be selectively connected to the target phase interface 172 in the AC power distribution interface 17 through different wiring combinations to change the type of converter.

[0084] The wiring combination is achieved through different wiring methods of the converter. Optionally, the wiring combination can be a structural component. For example, the structural component can be a copper busbar, that is, the connection is achieved through the copper busbar.

[0085] Optionally, the converter is a first type of converter, which further includes: a first structural component, which is used to plug into the first interface 102, the second interface 103, and the third interface 104, so that the first interface 102, the second interface 103, and the third interface 104 are connected in sequence, and the third interface 104 is connected to the target phase interface. The first type of converter can be a three-phase half-bridge converter.

[0086] Figure 4This is a schematic diagram of the internal structure of a three-phase half-bridge converter provided in an embodiment of the present invention;

[0087] Figure 5 This is a schematic diagram of the connection structure of a three-phase half-bridge converter provided in an embodiment of the present invention, as shown below. Figure 4 and 5 As shown, A, B, and C can be connected to UA, UB, and UC, respectively. N_LC, N_BUS, and N_SN are connected in sequence, and N_SN is connected to UN.

[0088] N_LC, N_BUS, and N_SN are connected sequentially, with N_SN connected to UN. This forms a typical three-phase half-bridge four-wire converter (i.e., a three-phase half-bridge converter) containing a bus equalization circuit (composed of an N-line filter and an N-line half-bridge circuit 14). The equalization circuit operates in grid-connected mode (such as DC constant voltage or AC constant power) and in off-grid mode (AC constant voltage).

[0089] Optionally, the converter is a second type of converter, which further includes a second structural component for plugging into the first interface 102, the second interface 103, and the third interface 104, so that the first interface 102 and the second interface 103 are connected, and the third interface 104 is connected to the target phase interface. The second type of converter is a three-phase four-arm converter.

[0090] N_LC is connected to N_BUS, N_LC and N_BUS are not connected to N_SN, and N_SN is connected to UN, forming a three-phase four-bridge arm four-wire converter (i.e., a three-phase four-bridge arm converter). The N-line half-bridge circuit 14 can control the N-line current.

[0091] Figure 6 This is a schematic diagram of the internal structure of a three-phase four-arm converter provided in an embodiment of the present invention. Figure 7 This is a schematic diagram of the connection structure of a three-phase four-arm converter provided in an embodiment of the present invention, as shown below. Figure 6 and 7 As shown, A, B, and C can be connected to UA, UB, and UC, respectively. N_LC is connected to N_BUS. Neither N_LC nor N_BUS is connected to N_SN. N_SN is connected to UN.

[0092] Optionally, the converter is a third type of converter, in which the first interface 102, the second interface 103, and the third interface 104 are not connected to each other, and the third interface 104 is also not connected to the target phase interface. The third type of converter is a three-phase full-bridge converter.

[0093] In this circuit, N_LC, N_BUS, and N_SN are not connected, and N_SN is also not connected to UN, forming a typical three-phase full-bridge three-wire converter (i.e., a three-phase full-bridge converter). The N-line filter and N-line half-bridge are still connected to the circuit, but there is no loop, so this part of the circuit does not work.

[0094] Figure 8 This is a schematic diagram of the internal structure of a three-phase full-bridge converter provided in an embodiment of the present invention. Figure 9 This is a schematic diagram of the connection structure of a three-phase full-bridge converter provided in an embodiment of the present invention, as shown below. Figure 8 and 9 As shown, A, B, and C can be connected to UA, UB, and UC, while N_LC, N_BUS, and N_SN are not connected, and N_SN is also not connected to UN.

[0095] Optionally, the converter may also include: a first switching device, a second switching device, and a third switching device;

[0096] The first switching device is disposed between the first interface 102 and the second interface 103, the second switching device is disposed between the second interface 103 and the third interface 104, and the third switching device is disposed between the third interface 104 and the target phase interface.

[0097] Specifically, by changing the switching states of the first, second, and third switching devices, the first, second, and third interfaces are selectively connected to the target phase interface in the AC power distribution interface, thereby changing the type of converter.

[0098] Optionally, the converter is a first type of converter, in which the first switching device, the second switching device, and the third switching device are all in the closed state. Figure 10 This is a schematic diagram of the switching device connection structure for a three-phase half-bridge converter provided in an embodiment of the present invention, as shown below. Figure 10 As shown, the first switching device S1, the second switching device S2, and the third switching device S3 are all in the closed state, so that N_LC, N_BUS, and N_SN are connected in sequence, and N_SN is connected to UN.

[0099] If the converter is a type 2 converter, then the first switching device S1 and the third switching device S3 are both in the closed state, and the second switching device S2 is in the open state, so that N_LC is connected to N_BUS, N_LC and N_BUS are not connected to N_SN, and N_SN is connected to UN.

[0100] If the converter is a third type of converter, then the first switching device S1, the second switching device S2, and the third switching device S3 are all in the off state, and N_LC, N_BUS, and N_SN are not connected. At the same time, N_SN and UN are also not connected.

[0101] Among them, the first type of converter is a three-phase half-bridge converter, the second type of converter is a three-phase four-bridge-arm converter, and the third type of converter is a three-phase full-bridge converter.

[0102] In summary, this invention provides a converter comprising: a multi-phase AC interface, a first interface connected to a first filter, a second interface connected to both the bridge arm output of a half-bridge circuit and a capacitor module, and a third interface connected to the bridge arm output of the half-bridge circuit. By selectively connecting the first, second, and third interfaces to target phase interfaces in the AC power distribution interface, the type of converter can be changed, enabling flexible switching between converter types. The structure of this converter facilitates user selection and use of different types of converters, improving the user experience. Furthermore, by setting structural components or switching devices for the first, second, and third interfaces, selective connection of the first, second, and third interfaces can be controlled, enabling switching between three types of converters.

[0103] Figure 11 This is a flowchart illustrating a control method for a converter provided in an embodiment of the present invention, applied to the aforementioned converter, such as... Figure 11 As shown, the method includes:

[0104] S1101, respond to the input for the selection operation of the converter type, and determine the target type converter from multiple preset types of converters.

[0105] In some implementations, the host computer can display multiple preset types of converters through an interface, respond to user input for selecting converter types, and determine the target type of converter from the multiple preset types of converters.

[0106] S1102. Send control commands corresponding to the target type of converter to the converter so that the converter changes the switching state of the first switching device, the second switching device, and the third switching device according to the control commands, and switches the converter to the target type of converter.

[0107] In this embodiment, if the first, second, and third switching devices are all in a closed state, the converter is a first type of converter; if the first and third switching devices are all in a closed state and the second switching device is in an open state, the converter is a second type of converter; if the first, second, and third switching devices are all in an open state, the converter is a third type of converter.

[0108] In summary, in response to input selection of converter type, the system determines the target type converter from multiple preset types and issues control commands corresponding to the target type to the converter. This causes the converter to change the switching states of its first, second, and third switching devices according to the control commands, thus switching the converter to the target type. This allows for automatic switching of the converter type, enabling transitions between three types of converters, facilitating user selection and use.

[0109] This invention also provides a control system for a converter, including the converter described above.

[0110] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A converter, characterized in that, include: Multiphase AC interface, first filter, full-bridge circuit, half-bridge circuit, capacitor module and DC interface; The multiphase AC interface, the first filter, the full-bridge circuit, the half-bridge circuit, the capacitor module, and the DC interface are connected in sequence; wherein, the multiphase AC interface is used to connect to the multiphase AC distribution interface in the AC distribution interface, and the AC distribution interface is used to provide AC power; The converter further includes: a first interface connected to the first filter, a second interface connected to both the bridge arm output terminal of the half-bridge circuit and the capacitor module, and a third interface connected to the bridge arm output terminal of the half-bridge circuit; the first interface, the second interface, and the third interface are selectively connected to the target phase interface UN in the AC power distribution interface to change the type of the converter; The converter is a first type of converter, and the first interface, the second interface, and the third interface are connected in sequence, with the third interface connected to the target phase interface; Alternatively, the converter is a second type of converter, with the first interface and the second interface connected to each other, and the third interface connected to the target phase interface; Alternatively, the converter may be a third type of converter, in which the first interface, the second interface, and the third interface are not connected to each other, and the third interface is not connected to the target phase interface; The converter also includes: a second filter; The third terminal of the second filter is connected to the bridge arm output terminal of the half-bridge circuit; the second interface is an interface connected to both the first terminal of the second filter and the capacitor module; the third interface is an interface connected to the second terminal of the second filter. The first filter is a three-phase filter, the full-bridge circuit is a three-phase full-bridge circuit, and the first interface is an interface connected to the midpoint of the capacitor of the three-phase filter.

2. The converter according to claim 1, characterized in that, The converter further includes an AC interface; the first interface, the second interface, the third interface, and the multiphase AC interface are integrated in the AC interface, and the AC interface is located near the AC distribution interface.

3. The converter according to claim 1, characterized in that, The first interface, the second interface, and the third interface are selectively connected to the target phase interface in the AC power distribution interface through different wiring combinations to change the type of the converter.

4. The converter according to claim 1, characterized in that, The converter further includes: a first switching device, a second switching device, and a third switching device; The first switching device is disposed between the first interface and the second interface, the second switching device is disposed between the second interface and the third interface, and the third switching device is disposed between the third interface and the target phase interface; Specifically, by changing the switching states of the first switching device, the second switching device, and the third switching device, the first interface, the second interface, and the third interface are controlled to selectively connect to the target phase interface in the AC power distribution interface, thereby changing the type of the converter.

5. The converter according to claim 1, characterized in that, The second filter includes a first capacitor and at least two first inductors connected in sequence. One end of the first capacitor is connected between the at least two first inductors, and the other end of the first capacitor is the first end of the second filter. The second end of the second filter is one end of the first of the at least two first inductors, and one end of the last of the at least two first inductors is connected to the bridge arm output of the half-bridge circuit.

6. The converter according to claim 1, characterized in that, The first filter includes multiple sets of devices, each set of devices including: a second capacitor and at least two second inductors connected in sequence; One end of the second capacitor is connected between the at least two second inductors, and the first interface is an interface connected to the other end of the second capacitor; One end of the first second inductor of the at least two second inductors in each group of devices is connected to the multiphase AC interface, and one end of the last second inductor of the at least two second inductors in each group of devices is connected to the full-bridge circuit.

7. A control method for a converter, characterized in that, Applied to the converter of claim 4, the method includes: In response to input selection operation for converter type, determine the target type converter from multiple preset converter types; A control command corresponding to the target type of converter is sent to the converter so that the converter changes the switching state of the first switching device, the second switching device, and the third switching device according to the control command, thereby switching the converter to the target type of converter.

8. A microgrid system, characterized in that, Includes the converter described in any one of claims 1-6.

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