Direct-current / alternating-current conversion circuit and energy storage and conversion apparatus

Abstract

The present disclosure relates to a direct-current / alternating-current conversion circuit and an energy storage and conversion apparatus. The direct-current / alternating-current conversion circuit comprises: three single-phase conversion circuits, a first end of each single-phase conversion circuit being a direct-current end, a second end of the single-phase conversion circuit being an alternating-current end, and the single-phase conversion circuit being used for mutual conversion between a direct-current current and a single-phase alternating-current current. When the second ends of the three single-phase conversion circuits are shorted, the alternating-current phases of the three single-phase conversion circuits are the same, and when the second ends of the three single-phase conversion circuits are not shorted, phase differences exist among the alternating-current phases of the three single-phase conversion circuits. The direct-current / alternating-current conversion circuit can be compatible with a three-phase power grid and a single-phase power grid, so that an energy storage device using the direct-current / alternating-current conversion circuit has good flexibility during grid connection.

Description

DC-AC conversion circuit and energy storage conversion device

[0001] Related applications

[0002] The present disclosure claims priority to Chinese Patent Application No. 2024111053519, filed on August 12, 2024, entitled "DC-AC Conversion Circuit", the contents of which are incorporated herein by reference in their entirety; the present disclosure claims priority to Chinese Patent Application No. 2025208457112, filed on April 29, 2025, entitled "Short-circuit Element and Energy Storage Conversion Device", the contents of which are incorporated herein by reference in their entirety; the present disclosure claims priority to Chinese Patent Application No. 2025213623856, filed on June 30, 2025, entitled "Single-phase DC-AC Conversion Circuit and Energy Storage Conversion Device", the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of power conversion, and in particular relates to a DC-AC conversion circuit and an energy storage conversion device. BACKGROUND

[0004] In the field of energy, in order to better regulate and distribute energy, some energy storage devices are needed to store electrical energy when the demand for electricity is low and release electrical energy when the demand for electricity is high. For example, some energy storage devices can store the electrical energy generated by photovoltaic power generation components during the day and release the electrical energy at night to supply power to loads in the power grid. Among them, when the energy storage device stores energy, it can convert alternating current into direct current and store it in the battery, and when the energy is released, it can be connected to the grid through a DC-AC conversion circuit.

[0005] Among them, the power grid includes a single-phase power grid and a three-phase power grid, but the DC-AC conversion circuit in the related art cannot simultaneously support the three-phase power grid and the single-phase power grid, resulting in poor flexibility when the energy storage device is connected to the grid. SUMMARY

[0006] Therefore, it is necessary to provide a DC-AC conversion circuit and an energy storage conversion device that can support three-phase power grids and single-phase power grids.

[0007] In a first aspect, a DC-AC conversion circuit is provided, comprising:

[0008] three single-phase conversion circuits, a first end of the single-phase conversion circuit being a DC end, a second end of the single-phase conversion circuit being an AC end, the single-phase conversion circuit being configured to convert between DC current and single-phase AC current;

[0009] In a case where the second ends of the three single-phase conversion circuits are shorted, the AC phases of the three single-phase conversion circuits are consistent, and in a case where the second ends of the three single-phase conversion circuits are not shorted, the AC phases of the three single-phase conversion circuits have a phase difference.

[0010] In one of the embodiments, in a case where the second ends of the three single-phase conversion circuits are not shorted, the AC phases of the three single-phase conversion circuits have a 120-degree phase difference between each other.

[0011] In one of the embodiments, the first end of the single-phase conversion circuit is a DC input end, the second end of the single-phase conversion circuit is an AC output end, and the single-phase conversion circuit is configured to convert an input DC current into a single-phase AC current.

[0012] In one of the embodiments, the first end of the single-phase conversion circuit is a DC output end, the second end of the single-phase conversion circuit is an AC input end, and the single-phase conversion circuit is configured to convert an input AC current into a DC current.

[0013] In one of the embodiments, the DC-AC conversion circuit comprises:

[0014] The AC terminal comprises a first phase interface, a second phase interface, a third phase interface, and a zero line interface, wherein the live wires in the second ends of the three single-phase conversion circuits are connected to the first phase interface, the second phase interface, and the third phase interface respectively, and the zero lines in the second ends of the three single-phase conversion circuits are connected to the zero line interface.

[0015] In a case where the first phase interface, the second phase interface, and the third phase interface are shorted, the AC phases of the three single-phase conversion circuits are consistent.

[0016] In one of the embodiments, the DC-AC conversion circuit further comprises:

[0017] The power distribution terminal comprises a first single board interface, a second single board interface, a third single board interface, and a fourth single board interface, wherein the first single board interface is connected to the first phase interface, the second single board interface is connected to the second phase interface, the third single board interface is connected to the third phase interface, and the fourth single board interface is connected to the zero line interface.

[0018] The power distribution terminal comprises a first power distribution interface, a second power distribution interface, a third power distribution interface, and a fourth power distribution interface.

[0019] In a case where the first power distribution interface, the second power distribution interface, and the third power distribution interface are shorted, the output phases of the three single-phase conversion circuits are consistent.

[0020] In one of the embodiments, the DC-AC conversion circuit further comprises:

[0021] A shorting element for shorting the first power distribution interface, the second power distribution interface and the third power distribution interface.

[0022] In one of the embodiments, the shorting element is for insertion into the power distribution terminal, the insertion direction of the shorting element is defined as the first direction, and the first direction, the second direction and the third direction are perpendicular to each other, the shorting element comprises:

[0023] The adapter unit comprises an adapter part and a pressing part, the adapter part is protrudingly arranged on the pressing part along the first direction, and the size of the pressing part along the second direction is greater than the size of the adapter part;

[0024] The mounting units are arranged on the adapter part along the third direction, and the mounting units are in conductive connection.

[0025] In one of the embodiments, along the second direction, the spacing between the adapter part and the end of the pressing part is 2mm to 3mm.

[0026] In one of the embodiments, the adapter part is recessed to form a groove near the pressing part.

[0027] In one of the embodiments, the two ends of the groove are spaced apart from the edges of the adapter part by a certain distance; and / or, the width of the groove is 1.5mm to 2.5mm.

[0028] In one of the embodiments, the adapter unit is an insulator, the mounting unit is a conductor, and / or;

[0029] The mounting units are connected by a conductive structure.

[0030] In one of the embodiments, the mounting unit comprises a support part and two edge springs, the support part is inserted into the adapter part, the edge springs are protrudingly arranged on the support part along the first direction, and the two edge springs are spaced apart along the second direction.

[0031] In one of the embodiments, the mounting unit comprises an intermediate spring and two edge springs, the intermediate spring is arranged between the two edge springs, and the intermediate spring and the two edge springs are connected at one end close to the adapter unit.

[0032] In one of the embodiments, the outer side surface of the edge spring in the second direction comprises a first connecting section and a second connecting section connected to each other at their ends, the second connecting section is connected to the end surface of the free end of the edge spring perpendicular to the first direction, the distance from the first connecting section to the middle spring is greater than the distance from the second connecting section to the middle spring, the distance from the first connecting section to the middle spring is equal, and the distance from the second connecting section to the middle spring decreases along the first direction from the adapter unit to the mounting unit.

[0033] In one of the embodiments, the outer side surface further comprises a third connecting section, the first connecting section is connected between the third connecting section and the second connecting section, the distance from the first connecting section to the middle spring is greater than the distance from the third connecting section to the middle spring, the distance from the third connecting section to the middle spring increases along the first direction from the adapter unit to the mounting unit.

[0034] In one of the embodiments, the middle spring and the edge spring are both provided with a through hole, the through hole penetrates the middle spring and the edge spring along the second direction.

[0035] In one of the embodiments, the outer surface of the power distribution terminal is recessed to form a plurality of short-circuit holes, a plurality of mounting units are respectively inserted into different short-circuit holes, and the abutting portion abuts against the outer surface of the power distribution terminal.

[0036] In one of the embodiments, the power distribution terminal is provided with a plurality of wiring holes, the plurality of wiring holes are arranged to form a plurality of rows on the power distribution terminal, each row comprises a plurality of live wire holes and one neutral wire hole, the live wire holes are used for cooperating with live wires, and the neutral wire hole is used for cooperating with a neutral wire.

[0037] In one of the embodiments, the short-circuit hole is located between two adjacent rows of wiring holes.

[0038] In one of the embodiments, the short-circuit holes are arranged to form a plurality of rows, the power distribution terminal comprises a partition wall simultaneously defining boundaries of two short-circuit holes arranged adjacent to each other in two adjacent rows, and the thickness of the partition wall is less than a set value.

[0039] In one of the embodiments, the first single board interface, the second single board interface, and the third single board interface are live wire holes, and the fourth single board interface is a neutral wire hole; and / or;

[0040] The short-circuit hole comprises a first power distribution interface, a second power distribution interface, a third power distribution interface, and a fourth power distribution interface.

[0041] In one of the embodiments, the direct-current alternating-current conversion circuit comprises:

[0042] A direct-current bus;

[0043] The first end of each of the three single-phase conversion circuits is connected in parallel to the DC bus line.

[0044] The DC bus line is used to combine at least one initial DC input current into one target DC input current, or to combine initial DC output currents of the three single-phase conversion circuits into one target DC output current.

[0045] In one embodiment, the DC-AC conversion circuit comprises:

[0046] The bus capacitor is connected in parallel to the DC bus line.

[0047] In one embodiment, the DC-AC conversion circuit comprises a first inductive element;

[0048] The first end of the first inductive element is connected to the DC bus line, and the second end of the first inductive element is used to be connected to an external DC circuit.

[0049] In one embodiment, the DC-AC conversion circuit comprises at least two second inductive elements; one second inductive element corresponds to one single-phase conversion circuit, the first end of the second inductive element is connected to the first end of the corresponding single-phase conversion circuit, and the second end of the second inductive element is connected to the DC bus line.

[0050] In one embodiment, the single-phase conversion circuit comprises a first topology circuit;

[0051] The first topology circuit comprises a DC side capacitor, a plurality of H-bridge circuits, a plurality of DC side windings, a plurality of AC side windings, and a secondary circuit, wherein,

[0052] The plurality of H-bridge circuits are connected in parallel to both ends of the DC side capacitor;

[0053] The plurality of H-bridge circuits are connected one-to-one to the plurality of DC side windings;

[0054] The plurality of AC side windings are connected in series to the secondary circuit.

[0055] In one embodiment, the single-phase conversion circuit comprises a second topology circuit;

[0056] The second topology circuit comprises a DC side capacitor, an H-bridge circuit, a DC side winding, an AC side winding, and a secondary circuit, wherein,

[0057] The H-bridge circuit is connected to both ends of the DC side capacitor;

[0058] The H-bridge circuit is connected to the DC side winding;

[0059] The AC side winding is connected to the secondary circuit.

[0060] In one embodiment, the single-phase conversion circuit comprises a plurality of first topology circuits;

[0061] The plurality of first topological circuits are connected in parallel.

[0062] In one of the embodiments, the single-phase conversion circuit comprises a second topological circuit;

[0063] The second topological circuit is different from the circuit topology of the first topological circuit;

[0064] The first topological circuit and the second topological circuit are connected in parallel.

[0065] In one of the embodiments, the single-phase conversion circuit comprises a third topological circuit;

[0066] The alternating-current side of the third topological circuit comprises an alternating-current side winding, a rectification circuit and a flip circuit;

[0067] A first end of the rectification circuit is connected to the alternating-current side winding, a second end of the rectification circuit is connected to a first end of the flip circuit, and the rectification circuit is configured to convert the first alternating current into a target pulsating current;

[0068] A second end of the flip circuit is configured to be connected to a power grid, and the flip circuit is configured to flip the target pulsating current into a second alternating current.

[0069] In one of the embodiments, the rectification circuit comprises a bridge rectification circuit and a filter capacitor, wherein,

[0070] A first end of the bridge rectification circuit is connected to the alternating-current side winding, a second end of the bridge rectification circuit is connected in parallel to the filter capacitor, the bridge rectification circuit is configured to convert the first alternating current into an initial pulsating current, and the filter capacitor is configured to filter the initial pulsating current to obtain the target pulsating current;

[0071] The first end of the flip circuit is connected in parallel to the filter capacitor.

[0072] In one of the embodiments, the filter capacitor has a capacitance value ranging from 1 microfarad to 10 microfarad.

[0073] In one of the embodiments, the filter capacitor is a film capacitor.

[0074] In one of the embodiments, the bridge rectification circuit comprises a half-bridge rectification circuit, a first resonant capacitor and a second resonant capacitor, wherein,

[0075] A first end of the half-bridge rectification circuit is connected to the alternating-current side winding, a second end of the half-bridge rectification circuit is connected in parallel to the filter capacitor, the half-bridge rectification circuit comprises a first switch tube and a second switch tube, and the first switch tube and the second switch tube have the same conduction direction;

[0076] The first resonant capacitor corresponds to the first switch tube, and the second resonant capacitor corresponds to the second switch tube.

[0077] In one of the embodiments, the bridge rectifier circuit comprises a third resonant capacitor and an H-bridge rectifier circuit.

[0078] The first end of the H-bridge rectifier circuit is connected to the AC side winding through the third resonant capacitor, and the second end of the H-bridge rectifier circuit is connected to the filter capacitor in parallel, the H-bridge rectifier circuit comprises a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, and the conduction directions of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are the same.

[0079] In one of the embodiments, the flip-flop circuit comprises an H-bridge flip-flop circuit, wherein,

[0080] The first bridge arm of the H-bridge flip-flop circuit comprises a seventh switch tube and an eighth switch tube, and the second bridge arm of the H-bridge flip-flop circuit comprises a ninth switch tube and a tenth switch tube.

[0081] In one of the embodiments, the AC side of the third topology circuit further comprises a filter circuit;

[0082] The second end of the flip-flop circuit is connected to the first end of the filter circuit;

[0083] The second end of the filter circuit is used for connecting to the power grid.

[0084] In one of the embodiments, the DC side of the third topology circuit comprises a DC side capacitor, a plurality of inverter H-bridge circuits, a plurality of DC side windings, and the number of the AC side windings is a plurality;

[0085] The plurality of inverter H-bridge circuits are connected in parallel to both ends of the DC side capacitor;

[0086] The plurality of inverter H-bridge circuits are connected one by one to the plurality of DC side windings;

[0087] The plurality of AC side windings are connected in series to the rectifier circuit.

[0088] In one of the embodiments, the DC-AC conversion circuit comprises:

[0089] The control circuit is used for controlling the AC phases of the three single-phase conversion circuits to have a phase difference in the case that the second ends of the three single-phase conversion circuits are not short-circuited, and controlling the AC phases of the three single-phase conversion circuits to be consistent in the case that the first ends of the single-phase conversion circuits are DC output ends and the second ends of the three single-phase conversion circuits are short-circuited.

[0090] In one of the embodiments, the control circuit comprises a first control circuit and three second control circuits, wherein,

[0091] The three second control circuits are respectively in communication connection with the three single-phase conversion circuits;

[0092] The first control circuit is in communication connection with the three second control circuits respectively.

[0093] In one of the embodiments, the control circuit comprises a first control circuit and a second control circuit, wherein,

[0094] The second control circuit is in communication connection with the three single-phase conversion circuits respectively;

[0095] The first control circuit is in communication connection with the second control circuit.

[0096] In one of the embodiments, the AC-DC conversion circuit comprises a circuit substrate;

[0097] The three single-phase conversion circuits are arranged on the circuit substrate.

[0098] In a second aspect, the present disclosure provides an energy storage conversion device, comprising: three single-phase conversion circuits, a first end of the single-phase conversion circuit being a DC end, a second end of the single-phase conversion circuit being an AC end, the single-phase conversion circuit being used for mutual conversion between DC current and single-phase AC current; in the case that the second end of the three single-phase conversion circuits is short-circuited by a short-circuit element, the AC phases of the three single-phase conversion circuits are consistent, in the case that the second end of the three single-phase conversion circuits is not short-circuited, there is a phase difference between the AC phases of the three single-phase conversion circuits;

[0099] The short-circuit element is used for being inserted in the power distribution terminal, the insertion direction of the short-circuit element is defined as a first direction, and the first direction, a second direction and a third direction are perpendicular to each other, the short-circuit element comprises: a switching unit comprising a switching part and a pressing part, the switching part is protrudingly arranged on the pressing part along the first direction, and the size of the pressing part along the second direction is greater than the size of the switching part; a mounting unit, the number of the mounting unit is multiple, the multiple mounting units are arranged on the switching part along the third direction, and the multiple mounting units are in conductive connection;

[0100] The power distribution terminal has an outer surface, and a plurality of short-circuit holes are recessed in the outer surface of the power distribution terminal, the multiple mounting units are respectively inserted in different short-circuit holes, and the pressing part abuts against the outer surface of the power distribution terminal.

[0101] In one of the embodiments, the power distribution terminal is provided with a plurality of wiring holes, the plurality of wiring holes are arranged in multiple rows on the power distribution terminal, each row comprises a plurality of live wire holes and a zero line hole, the live wire holes are used for cooperating with live wires, and the zero line hole is used for cooperating with a zero line.

[0102] In one of the embodiments, the short-circuit hole is located between two adjacent rows of wiring holes.

[0103] In one of the embodiments, the short-circuit holes are arranged in multiple rows, the power distribution terminal comprises a partition wall which simultaneously defines the boundaries of two short-circuit holes arranged adjacent to each other in two adjacent rows, and the thickness of the partition wall is less than a set value.

[0104] In one of the embodiments, the power distribution terminal comprises a first single-board interface, a second single-board interface, a third single-board interface, and a fourth single-board interface, the first single-board interface, the second single-board interface, and the third single-board interface are firewire holes, and the fourth single-board interface is a zero wire hole; and / or,

[0105] The short circuit hole comprises a first power distribution interface, a second power distribution interface, a third power distribution interface, and a fourth power distribution interface; in the case where the first power distribution interface, the second power distribution interface, and the third power distribution interface are short-circuited, the phases of the first power distribution interface, the second power distribution interface, and the third power distribution interface are consistent.

[0106] In the case where the second ends of the three single-phase conversion circuits are short-circuited, the AC phases of the three single-phase conversion circuits are consistent, so that the DC-AC conversion circuit as a whole is used for conversion between single-phase AC current and DC current; in the case where the second ends of the three single-phase conversion circuits are not short-circuited, there is a phase difference between the AC phases of the three single-phase conversion circuits, so that the DC-AC conversion circuit as a whole is used for conversion between three-phase AC current and DC current, so that the DC-AC conversion circuit can be compatible with three-phase power grid and single-phase power grid, and the energy storage device using the DC-AC conversion circuit has better flexibility when connected to the grid. BRIEF DESCRIPTION OF DRAWINGS

[0107] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present disclosure, and other drawings can also be obtained according to the disclosed drawings without creative labor for those skilled in the art.

[0108] FIG. 1 is a structural schematic diagram of a DC-AC conversion circuit in one embodiment;

[0109] FIG. 2 is a structural schematic diagram of a DC-AC conversion circuit in another embodiment;

[0110] FIG. 3 is a structural schematic diagram of a DC-AC conversion circuit in another embodiment;

[0111] FIG. 4 is a structural schematic diagram of a DC-AC conversion circuit in another embodiment;

[0112] FIG. 5 is a structural schematic diagram of a DC-AC conversion circuit in another embodiment;

[0113] FIG. 6 is a topological structural schematic diagram of a first topological circuit in one embodiment;

[0114] FIG. 7 is a topological structural schematic diagram of a second topological circuit in one embodiment;

[0115] Figure 8 is a block diagram of a single-phase DC-AC conversion circuit in one embodiment;

[0116] Figure 9 is a waveform diagram of a target pulsed current in one embodiment;

[0117] Figure 10 is a waveform diagram of a target pulsed current in another embodiment;

[0118] Figure 11 is a block diagram of a single-phase DC-AC conversion circuit in another embodiment;

[0119] Figure 12 is a circuit topology diagram of a single-phase DC-AC conversion circuit in one embodiment;

[0120] Figure 13 is a circuit topology diagram of a single-phase DC-AC conversion circuit in another embodiment;

[0121] Figure 14 is a communication line structure diagram of a DC-AC conversion circuit in one embodiment;

[0122] Figure 15 is a communication line structure diagram of a DC-AC conversion circuit in another embodiment;

[0123] Figure 16 is a partial perspective view of an energy storage conversion device in one embodiment;

[0124] Figure 17 is a perspective view of a shorting element in the energy storage conversion device of Figure 1;

[0125] Figure 18 is a front view of the shorting element of Figure 11;

[0126] Figure 19 is a side view of the shorting element of Figure 11;

[0127] Figure 20 is a partial perspective view of an energy storage conversion device in one embodiment.

[0128] 100, single-phase conversion circuit; 200, power distribution terminal; 210, shorting hole; 211, first power distribution interface; 212, second power distribution interface; 213, third power distribution interface; 214, fourth power distribution interface; 220, wiring hole; 220a, live wire hole; 220b, neutral wire hole; 221, first single-board interface; 222, second single-board interface; 223, third single-board interface; 224, fourth single-board interface; 230, outer surface; 240, partition wall; 300, circuit substrate; 400, shorting element; 410, adapter unit; 411, pressing portion; 412, adapter portion; 4121, groove; 420, mounting unit; 421, support portion; 422, edge spring; 4221, first connecting segment; 4222, second connecting segment; 4223, third connecting segment; 423, intermediate spring; 424, through hole; 500, DC bus; 610, AC-side winding; 620, rectification circuit; 621, bridge rectification circuit; 630, inversion circuit; 640, DC-side winding; 650, inverter H-bridge circuit; 660, filter circuit; 700, first control circuit; 800, second control circuit; 900, upper computer; 1000, energy storage conversion device. DETAILED DESCRIPTION

[0129] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present disclosure.

[0130] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure.

[0131] It can be understood that the terms "first", "second", and the like used in the present disclosure can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of the present disclosure, a first resistor can be referred to as a second resistor, and similarly, a second resistor can be referred to as a first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0132] It can be understood that "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the circuits, modules, units, etc. connected to each other have transmission of electrical signals or data.

[0133] In the description of the present disclosure, it needs to be understood that if these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present disclosure.

[0134] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" or "including" or "having" or the like, specifies the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0135] In the present disclosure, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0136] In the present disclosure, unless otherwise explicitly specified and limited, if the first feature appears "on" or "under" the second feature and the like, it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0137] It is to be noted that if an element is referred to as being "fixed" or "set" on another element, it can be directly on the other element or there can be an intervening element. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used herein for illustrative purposes only and do not indicate the only implementation.

[0138] In one exemplary embodiment, referring to FIG. 1, a direct current alternating current conversion circuit is provided, comprising: three single-phase conversion circuits 100.

[0139] Wherein, the first end of the single-phase conversion circuit 100 is a direct current end, the second end of the single-phase conversion circuit 100 is an alternating current end, and the single-phase conversion circuit 100 is used for mutual conversion between direct current and single-phase alternating current.

[0140] Wherein, in the case that the second ends of the three single-phase conversion circuits 100 are short-circuited, the alternating current phases of the three single-phase conversion circuits 100 are consistent, and in the case that the second ends of the three single-phase conversion circuits 100 are not short-circuited, the alternating current phases of the three single-phase conversion circuits 100 have a phase difference.

[0141] Wherein, the three phases of a general three-phase alternating current grid are 120 degrees apart from each other, but in some special cases, such as unbalanced load of the three-phase alternating current grid, unstable output of the generator, etc., the three phases of the three-phase alternating current grid cannot be 120 degrees apart from each other at all times; when the three-phase alternating current grid is connected in parallel using the direct current alternating current conversion circuit provided in the embodiment, i.e. in the case that the second ends of the three single-phase conversion circuits are not short-circuited, the alternating current phases of the three single-phase conversion circuits 100 are controlled to have a phase difference, so that the alternating current phases of the three single-phase conversion circuits 100 are respectively matched with the phases of the currently connected three-phase alternating current grid.

[0142] In one possible implementation, in the case that the second ends of the three single-phase conversion circuits 100 are not short-circuited, the alternating current phases of the three single-phase conversion circuits 100 are 120 degrees apart from each other.

[0143] Wherein, when the second ends of the three single-phase conversion circuits 100 are short-circuited, the single-phase alternating current input or output by the direct current alternating current conversion circuit is the superposition of the three single-phase conversion circuits 100, and compared with the case that the second ends of the three single-phase conversion circuits 100 are not short-circuited, the alternating current input / output by the direct current alternating current conversion circuit is larger (it is to be noted that in the case that the direct current input is unchanged), so that the direct current alternating current conversion circuit provided in the embodiment can naturally adapt to the flexible parallel connection and access of the single-phase alternating current grid and the three-phase alternating current grid.

[0144] In the case that the second ends of the three single-phase conversion circuits 100 are short-circuited, the three single-phase conversion circuits 100 have consistent AC phases, so that the DC-AC conversion circuit as a whole is used for conversion between single-phase AC current and DC current; in the case that the second ends of the three single-phase conversion circuits 100 are not short-circuited, the three single-phase conversion circuits 100 have phase differences, so that the DC-AC conversion circuit as a whole is used for conversion between three-phase AC current and DC current. Thus, the DC-AC conversion circuit provided in the embodiment can be compatible with three-phase power grids and single-phase power grids, so that the energy storage device applying the DC-AC conversion circuit has better flexibility when connected to a power grid.

[0145] Further, the DC-AC conversion circuit provided in the embodiment can not only flexibly connect the energy storage device to a single-phase power grid and a three-phase power grid, but also flexibly obtain electric energy from the single-phase power grid and the three-phase power grid. In this way, the energy storage device applying the DC-AC conversion circuit provided in the embodiment can flexibly adapt to the peak and valley periods of a single-phase power grid and / or a three-phase power grid to shave the peak and fill the valley, thereby improving the flexibility of power resource scheduling.

[0146] In an exemplary embodiment, the first end of the single-phase conversion circuit 100 is a DC input end, and the second end of the single-phase conversion circuit 100 is an AC output end. The single-phase conversion circuit 100 is used to convert input DC current into single-phase AC current.

[0147] In the case that the second ends of the three single-phase conversion circuits 100 are short-circuited, the three single-phase conversion circuits 100 are respectively used to convert input DC current into single-phase AC current with consistent phases. At this time, the DC-AC conversion circuit can be regarded as a single-phase converter, which can be applied to a scenario in which an energy storage device or other DC device is connected to a single-phase power grid.

[0148] In the case that the second ends of the three single-phase conversion circuits 100 are not short-circuited, the three single-phase conversion circuits 100 are respectively used to convert input DC current into three single-phase AC currents with phase differences, so that the AC current output by each single-phase conversion circuit 100 matches one phase of a three-phase power grid. At this time, the DC-AC conversion circuit can be regarded as a three-phase converter, which can be applied to a scenario in which an energy storage device or other DC device is connected to a three-phase power grid.

[0149] The DC-AC conversion circuit provided in the embodiment can be compatible with the functions of single-phase converters and multi-phase converters, so that the energy storage device applying the DC-AC conversion circuit can be flexibly connected to a power grid. Of course, the DC-AC conversion circuit provided in the embodiment can also be applied to the connection between other DC devices and other AC devices.

[0150] In an example embodiment, the first end of the single-phase conversion circuit 100 is a direct current output end, the second end of the single-phase conversion circuit 100 is an alternating current input end, and the single-phase conversion circuit 100 is configured to convert an input alternating current into a direct current.

[0151] In the case where the second ends of the three single-phase conversion circuits 100 are short-circuited, the three single-phase conversion circuits 100 are respectively configured to convert an input single-phase alternating current into a direct current, and in this case, the direct alternating conversion circuit can be regarded as a single-phase converter and can be applied to a scenario in which an energy storage device or other direct current device obtains power from a single-phase alternating current power grid.

[0152] In the case where the second ends of the three single-phase conversion circuits 100 are not short-circuited, the three single-phase conversion circuits 100 are respectively configured to convert one phase of an input three-phase alternating current into a direct current, and in this case, the direct alternating conversion circuit can be regarded as a three-phase converter and can be applied to a scenario in which an energy storage device or other direct current device accesses a three-phase alternating current power grid.

[0153] The direct alternating conversion circuit provided in this embodiment can be compatible with the functions of single-phase converters and three-phase converters, so that an energy storage device using the direct alternating conversion circuit can flexibly access a power grid. Of course, the direct alternating conversion circuit provided in this embodiment can also be applied to the connection between other direct current devices and other alternating current devices.

[0154] In an example embodiment, referring to FIG. 1, the direct alternating conversion circuit includes an alternating current terminal. As shown in FIG. 1, the alternating current terminal includes a first phase interface U1, a second phase interface V1, a third phase interface W1, and a zero line interface N1. In this embodiment, the live wires in the second ends of the three single-phase conversion circuits 100 are respectively connected to the first phase interface U1, the second phase interface V1, and the third phase interface W1, and the zero lines in the second ends of the three single-phase conversion circuits 100 are all connected to the zero line interface N1.

[0155] In this embodiment, in the case where the first phase interface U1, the second phase interface V1, and the third phase interface W1 are short-circuited, the alternating current phases of the three single-phase conversion circuits 100 are consistent.

[0156] Correspondingly, in the case where the first phase interface U1, the second phase interface V1, and the third phase interface W1 are not short-circuited, the alternating current phases of the three single-phase conversion circuits 100 have a phase difference; optionally, the alternating current phases of the three single-phase conversion circuits 100 have a phase difference of 120 degrees between any two of them.

[0157] In an example, the alternating current terminal further includes a ground line interface for grounding the direct alternating conversion circuit to ensure the safety of the direct alternating conversion circuit.

[0158] The direct-current alternating-current conversion circuit provided in the embodiment comprises an alternating-current terminal, facilitating connection of the second end of each single-phase conversion circuit 100 with external equipment, and improving reliability of use of the direct-current alternating-current conversion circuit.

[0159] In one exemplary embodiment, referring to FIGS. 2 and 3, based on the embodiment shown in FIG. 1, the direct-current alternating-current conversion circuit provided in the embodiment further comprises a power distribution terminal 200. The power distribution terminal 200 comprises a first single-board interface U2, a second single-board interface V2, a third single-board interface V3 and a fourth single-board interface V4, wherein the first single-board interface U2 is connected with the first-phase interface U1, the second single-board interface V2 is connected with the second-phase interface V1, the third single-board interface W2 is connected with the third-phase interface W1, and the fourth single-board interface N2 is connected with the zero-line interface N1.

[0160] The power distribution terminal 200 comprises a first power distribution interface U3, a second power distribution interface V3, a third power distribution interface W3 and a fourth power distribution interface W4. In the case that the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3 are short-circuited, the output phases of the three single-phase conversion circuits 100 are consistent.

[0161] The direct-current alternating-current conversion circuit provided in the embodiment comprises the power distribution terminal 200, and when the direct-current alternating-current conversion circuit is connected with the single-phase alternating-current power grid, the second ends of the three single-phase conversion circuits 100 are short-circuited by short-circuiting the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3 of the power distribution terminal 200.

[0162] In the embodiment, the power distribution terminal 200 can be used as a mechanical structure for connecting the energy storage equipment configuring the direct-current alternating-current conversion circuit with the power grid. The direct-current end of the direct-current alternating-current conversion circuit is connected with the energy storage equipment, and the alternating-current end is connected with the power grid based on the power distribution terminal 200. It can be understood that, referring to FIGS. 2 and 3, the power distribution terminal 200 (including the power distribution terminal 200) is in the first direction, which is the energy storage equipment part, and the power distribution terminal 200 is in the second direction (including the short-circuiting element 400), which is the field wiring part.

[0163] In a possible implementation of the embodiment, referring to FIG. 2 and FIG. 3, three single-phase conversion circuits 100 and AC terminals are arranged on the same circuit substrate 300, and the circuit connection between the AC terminals of the single-phase conversion circuits 100 is realized by internal wiring of the circuit substrate 300; the wires are connected between the AC terminals and the power distribution terminals 200; in this way, the circuit substrate 300 and the power distribution terminals 200 can be arranged in separate cavities, for example, the circuit substrate 300 can be arranged in the power cavity of the energy storage device, so that the protection level of the circuit substrate 300 is higher, and the circuit substrate 300 will not be affected by the external environment, at the same time, the user will not touch the live device, improving the safety of user use; the power distribution terminals 200 can be arranged in the maintenance cavity, so that the user can conveniently carry out on-site wiring and is easy to maintain.

[0164] For example, the circuit substrate 300 can be realized by a PCB (Printed Circuit Board).

[0165] In an example embodiment, referring to FIG. 3, based on the embodiment of FIG. 2, the DC-AC conversion circuit provided in the embodiment further includes a short-circuit element 400. The short-circuit element 400 is used to short-circuit the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3. For example, the short-circuit element 400 is a short-circuit copper bar. In the case where the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3 need to be short-circuited, the short-circuit element 400 is used to connect the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3, and then any one of the first power distribution interface U3, the second power distribution interface V3 and the third power distribution interface W3 is connected with the single-phase AC power grid connection interface.

[0166] In an example embodiment, referring to FIG. 1 to FIG. 3, the provided DC-AC conversion circuit includes a DC bus 500. The first end of each of the three single-phase conversion circuits 100 is connected in parallel with the DC bus 500, and the DC bus 500 is used to combine at least one initial DC input current into a target DC input current, or is used to combine the initial DC outputs of the three single-phase conversion circuits 100 into a target DC output current.

[0167] In a possible implementation, the first end of the single-phase conversion circuit 100 is a DC input end, the DC bus 500 is an input end of the whole DC-AC conversion circuit, and the DC input ends of the three single-phase conversion circuits 100 are connected in parallel to the DC bus 500, that is, the three single-phase conversion circuits 100 are connected to the same DC input current. Exemplarily, the DC side of the DC-AC conversion circuit is connected to one energy storage device through the DC bus 500; and exemplarily, the DC side of the DC-AC conversion circuit is connected to multiple energy storage devices through the DC bus 500, and the three single-phase conversion circuits 100 are connected to the same target DC input current through the DC bus 500, which can be understood as that the three single-phase conversion circuits 100 perform DC-AC conversion on the same DC source.

[0168] In a possible implementation, the first end of the single-phase conversion circuit 100 is a DC output end, the DC bus 500 is an output end of the whole DC-AC conversion circuit, and the DC output ends of the three single-phase conversion circuits 100 are connected in parallel to the DC bus 500, that is, the three single-phase conversion circuits 100 are connected to the same DC output end. Exemplarily, the DC side of the DC-AC conversion circuit is connected to one energy storage device through the DC bus 500, and the DC currents output by the three single-phase conversion circuits 100 are converged into one target DC output current through the DC bus 500 and output to the energy storage device; and exemplarily, the DC side of the DC-AC conversion circuit is connected to multiple energy storage devices through the DC bus 500, the DC currents output by the three single-phase conversion circuits 100 are converged into one target DC output current through the DC bus 500, and then the target DC output current is distributed to each energy storage device.

[0169] The DC bus 500 is a DC convergence structure, and the position of the DC bus 500 on the circuit board is fixed. The length of the external line corresponds to the position of the DC bus 500, so that, in the process of wiring, if the external lines connected to DC+ and DC- are connected reversely, the DC bus 500 cannot be connected to DC+ and DC- of the DC bus 500, and the DC bus 500 can naturally prevent the external lines from being connected reversely. The DC side of the DC-AC conversion circuit provided in the embodiment is connected to each single-phase conversion circuit 100 through the DC bus 500, the number of input wiring is reduced, the situation of reverse connection of the DC side is avoided, a separate reverse connection prevention circuit does not need to be added, the hardware cost of the DC-AC conversion circuit is reduced, and the working efficiency of the DC-AC conversion circuit is improved.

[0170] In one example embodiment, referring to FIG. 2 and FIG. 3, the provided DC-AC conversion circuit includes a bus capacitor C1 connected in parallel with the DC bus 500. The bus capacitor C1 is connected between the positive and negative poles of the DC bus 500 to absorb the high-frequency ripple voltage generated by the single-phase conversion circuit. In this embodiment, the bus capacitor C1 is provided in parallel with the DC bus 500, so that the electrolytic capacitor does not need to be provided in the single-phase conversion circuit 100, thereby reducing the hardware cost of the DC-AC conversion circuit.

[0171] In one example embodiment, referring to FIG. 2 and FIG. 3, the provided DC-AC conversion circuit includes a first inductive element. The first end of the first inductive element is connected to the DC bus 500, and the second end of the first inductive element is used to connect to an external DC circuit. In this way, the inductive element is added between the DC bus 500 and the external DC circuit, which can filter the high-frequency noise in the DC side current.

[0172] For example, the first inductive element includes an inductor L1 and an inductor L2, the inductor L1 is connected to the positive pole of the DC bus 500, and the inductor L2 is connected to the negative pole of the DC bus 500.

[0173] In one example embodiment, referring to FIG. 4 and FIG. 5, the provided DC-AC conversion circuit includes at least two second inductive elements. One of the second inductive elements corresponds to one single-phase conversion circuit, the first end of the second inductive element is connected to the first end of the corresponding single-phase conversion circuit, and the second end of the second inductive element is connected to the DC bus.

[0174] In one possible implementation, referring to FIG. 4, the provided DC-AC conversion circuit includes two second inductive elements. The first ends of the two second inductive elements are respectively connected to the first ends of any two single-phase conversion circuits of the three single-phase conversion circuits, and the second ends of the two second inductive elements are respectively connected to the DC bus. For example, as shown in FIG. 4, the two second inductive elements are inductors L3 and L4, wherein the inductor L3 is arranged between the positive pole of the DC bus and the first end of one single-phase conversion circuit 100, and the inductor L4 is arranged between the positive pole of the DC bus and the first end of another single-phase conversion circuit 100; the first end of the third single-phase conversion circuit 100 and the positive pole of the DC bus are not provided with a second inductive element. In other examples, the two second inductive elements are respectively arranged between the negative pole of the DC bus and the first end of the corresponding single-phase conversion circuit 100.

[0175] In a possible implementation, referring to FIG. 5, the provided DC-AC conversion circuit includes three second inductive elements. The first ends of the three second inductive elements are respectively connected to the first ends of the three single-phase conversion circuits, and the second ends of the three second inductive elements are respectively connected to the DC bus. For example, as shown in FIG. 5, the three second inductive elements are inductance L3, inductance L4 and inductance L5, and the inductance L3, the inductance L4 and the inductance L5 are respectively arranged between the positive pole of the DC bus and the first end of the corresponding single-phase conversion circuit 100. In other examples, the three second inductive elements are respectively arranged between the negative pole of the DC bus and the first end of the corresponding single-phase conversion circuit 100.

[0176] In the DC-AC conversion circuit in the embodiment of the present disclosure, the three single-phase conversion circuits are connected in parallel with the DC bus, the switching frequency range of each single-phase conversion circuit is relatively large, for example, the switching frequency range of the single-phase conversion circuit using the dual active bridge (DAB) is 75 kHz to 200 kHz, and the switching frequency difference between the single-phase conversion circuits can exist. The second inductive element arranged between the first end of the single-phase conversion circuit and the DC bus can prevent the switching action in the corresponding single-phase conversion circuit from forming a high-frequency ripple on the DC bus, thereby avoiding the switching sub-resonance between the three single-phase conversion circuits, and the problems of high-frequency peaks in the voltage or current waveform, serious electromagnetic interference or damage to the bus capacitor and other elements. The second inductive element arranged between the first end of the single-phase conversion circuit and the DC bus increases the impedance in the switching path, avoids the switching sub-resonance phenomenon in the three single-phase conversion circuits, and avoids the problem of serious electromagnetic interference. The DC-AC conversion circuit provided in the embodiment decouples the high-frequency mutual influence between the three single-phase conversion circuits through the second inductive element, and improves the stability and reliability of the circuit.

[0177] In an example embodiment, the single-phase conversion circuit 100 includes a first topology circuit. The first topology circuit includes a DC side capacitor, a plurality of H-bridge circuits, a plurality of DC side windings, a plurality of AC side windings and a secondary side circuit. The plurality of H-bridge circuits are connected in parallel to the two ends of the DC side capacitor, and the plurality of H-bridge circuits are connected to the plurality of DC side windings one by one. The plurality of AC side windings are connected in series to the secondary side circuit. It should be noted that in the embodiment in which the second end of the single-phase conversion circuit 100 is an AC input end, the secondary side circuit is an AC input circuit.

[0178] In a possible implementation, the secondary side circuit is a half-bridge circuit.

[0179] Please refer to FIG. 6. For the convenience of presentation, the circuit structure of the first topology circuit provided in the embodiment is described by taking an example of the first topology circuit including two H-bridge circuits, two DC side windings and two AC side windings. In the example, please refer to FIG. 6. The DC side capacitor includes capacitor C2. The first bridge arm of the first H-bridge circuit includes switch T 11 and switch T 12 . The second bridge arm of the first H-bridge circuit includes switch T 13 and switch T 14 . The middle point of switch T 11 and switch T 12 and the middle point of switch T 13 and switch T 14 are connected to the DC side winding of transformer TS1 as the interface of the first H-bridge circuit. The first bridge arm of the second H-bridge circuit includes switch T 21 and switch T 22 . The second bridge arm of the first H-bridge circuit includes switch T 23 and switch T 24 . The middle point of switch T 21 and switch T 22 and the middle point of switch T 23 and switch T 24 are connected to the DC side winding of transformer TS2 as the interface of the second H-bridge circuit. The AC side winding of transformer TS1 and the AC side winding of transformer TS2 are connected in series to the secondary side circuit. The upper bridge arm of the secondary side circuit is realized by the bidirectional switch composed of switch T5 and switch T6. The lower bridge arm of the secondary side circuit is realized by the bidirectional switch composed of switch T7 and switch T8.

[0180] In a possible implementation, the first topology circuit includes two AC side capacitors, which correspond to the two bridge arms of the secondary side circuit respectively. In the example shown in FIG. 6, the two AC side capacitors are capacitor C3 and capacitor C4 respectively, wherein capacitor C3 corresponds to the upper bridge arm of the secondary side circuit, capacitor C4 corresponds to the lower bridge arm of the secondary side circuit, capacitor C3 and capacitor C4 can be used as the resonance capacitor on the AC side, together with the leakage inductance of the transformer or a separate inductor to form a resonance circuit, at the same time, capacitor C3 and capacitor C4 can be used as the voltage doubling capacitor to realize the voltage doubling on the AC side; capacitor C3 and capacitor C4 can be used as the differential mode filter capacitor on the AC side.

[0181] In a possible implementation, the first topology circuit can also be provided with other forms of circuit topology structure on the AC side. For example, a resonance capacitor is arranged between the AC side winding and the secondary side circuit to form a resonance circuit together with the leakage inductance of the transformer or a separate inductor.

[0182] It can be understood that, in actual application, the number of H-bridge circuits in the first topology circuit and the corresponding transformers (i.e., the direct current side winding and the alternating current side winding) are determined according to specific application scenarios.

[0183] In a possible implementation, the first end of the single-phase conversion circuit 100 is a direct current input end, the second end of the single-phase conversion circuit 100 is an alternating current output end, the first topology circuit is used as the single-phase conversion circuit 100, and a plurality of H-bridge circuits are connected in parallel, which can share the input direct current. Each H-bridge circuit is connected to a direct current side winding, and all alternating current side windings are connected in series to the secondary side circuit, and an alternating current is output.

[0184] In this way, in the case that the current value corresponding to the direct current side of the direct current alternating current conversion circuit is large, the current is shared by the plurality of H-bridge circuits, so that the current corresponding to a single H-bridge circuit in a single single-phase conversion circuit 100 is small, the complexity of loss control and thermal design of the switch tube in the H-bridge circuit is reduced, and it is suitable for various scenes including low-voltage and large-current direct current sides.

[0185] In an exemplary embodiment, the single-phase conversion circuit 100 includes a second topology circuit, wherein the second topology circuit includes a direct current side capacitor, an H-bridge circuit, a direct current side winding, an alternating current side winding, and a secondary side circuit, wherein the H-bridge circuit is connected to both ends of the direct current side capacitor; the H-bridge circuit is connected to the direct current side winding; and the alternating current side winding is connected to the secondary side circuit.

[0186] Please refer to FIG. 7 for an exemplary schematic diagram of the structure of the second topology circuit provided in this embodiment. The direct current side capacitor includes a capacitor C2, only one H-bridge circuit and one corresponding transformer TS1 are provided, wherein the first bridge arm of the H-bridge circuit includes a switch tube T 11 and a switch tube T 12 , the second bridge arm of the H-bridge circuit includes a switch tube T 13 and a switch tube T 14 , the middle point of the switch tube T 11 and the switch tube T 12 , and the middle point of the switch tube T 13 and the switch tube T 14 are connected to the direct current side winding of the transformer TS1 as the interface of the first H-bridge circuit; the alternating current side winding of the transformer TS1 is connected to the secondary side circuit; the upper bridge arm of the secondary side circuit is realized by a bidirectional switch composed of a switch device T5 and a switch device T6, and the lower bridge arm of the secondary side circuit is realized by a bidirectional switch composed of a switch tube T7 and a switch tube T8.

[0187] In one possible implementation, the second topology circuit includes two AC side capacitors, wherein the two AC side capacitors correspond to two bridge arms of the secondary side circuit respectively. Similar to the example shown in FIG. 6, in the example shown in FIG. 7, the two AC side capacitors are capacitor C3 and capacitor C4 respectively, and the positions and functions of the capacitor C3 and the capacitor C4 can refer to the description of the capacitor C3 and the capacitor C4 in the example shown in FIG. 6, which will not be repeated here.

[0188] In one example embodiment, the single-phase conversion circuit 100 includes a plurality of first topology circuits; wherein the plurality of first topology circuits are connected in parallel.

[0189] In one example embodiment, the single-phase conversion circuit 100 includes a plurality of second topology circuits; wherein the plurality of second topology circuits are connected in parallel.

[0190] In one example embodiment, the single-phase conversion circuit 100 includes a first topology circuit and a second topology circuit. Wherein the circuit topology of the second topology circuit is different from the circuit topology of the first topology circuit; the first topology circuit and the second topology circuit are connected in parallel. For example, the circuit topology of the second topology circuit in the present embodiment can adopt the circuit topology shown in FIG. 7, or other circuit topologies that can realize the mutual conversion between direct current and single-phase alternating current.

[0191] The number of the first topology circuit and the second topology circuit included in the single-phase conversion circuit 100 in the present embodiment is not limited. For example, the single-phase conversion circuit 100 includes one first topology circuit and a plurality of second topology circuits; for another example, the single-phase conversion circuit 100 includes a plurality of first topology circuits and one second topology circuit; for another example, the single-phase conversion circuit 100 includes a plurality of first topology circuits and a plurality of second topology circuits.

[0192] In one example implementation, referring to FIG. 8, the AC side of a third topology circuit provided includes an AC side winding 610, a rectifier circuit 620 and a flip circuit 630.

[0193] Wherein the first end of the rectifier circuit 620 is connected with the AC side winding 610, the second end of the rectifier circuit 620 is connected with the first end of the flip circuit 630, and the rectifier circuit 620 is used to convert the first alternating current into a target pulsating current.

[0194] Wherein the first alternating current is a high-frequency alternating pulse current output by the AC side winding 610, the frequency of the target pulsating current is twice the power grid frequency, the amplitude of the target pulsating current is determined based on the amplitude of the power grid alternating current, and the waveform of the target pulsating current is a steamed bun waveform as shown in FIG. 9 or FIG. 10.

[0195] In the embodiment, the rectifier circuit 620 realizes conversion of the first alternating current into a pulse current with unchanged polarity, and therefore, the switching tube included in the rectifier circuit 620 can be a switching tube with consistent conduction direction. In some special working conditions (for example, clamping), the current on the inductor can be led out to the alternating current bus without being loaded on both ends of the switching tube, without special control for the special working conditions, so that the control logic of the rectifier circuit 620 is simple.

[0196] For example, the power frequency of the power grid is 50 Hz (hertz) or 60 Hz, and correspondingly, the target pulse current has a power of 610 Hz or 120 Hz.

[0197] The second end of the inverter circuit 630 is used to connect the power grid, for inverting the target current into a second alternating current. The frequency of the second alternating current is equal to the power frequency, and the amplitude of the second alternating current is determined based on the amplitude of the alternating current of the power grid.

[0198] In the embodiment, the inverter circuit 630 realizes conversion of the steamed bun waveform target pulse current into a sine wave form of the power grid current, and the switching frequency of the switching tube in the inverter circuit 630 is twice the power frequency, reducing the switching loss of the inverter circuit 630. Therefore, the inverter circuit 630 can select a low-frequency switching tube to reduce the hardware cost. For example, the switching frequency of the switching tube in the inverter circuit 630 is 100 Hz or 120 Hz.

[0199] The third topology circuit provided in the above embodiment avoids the problem of complex control logic of the alternating current side in the related art caused by using a half-bridge circuit composed of bidirectional switching tubes to directly convert the high-frequency alternating current output by the alternating current side winding into a sine wave form of alternating current. The third topology circuit provided in the embodiment converts the first alternating current output by the alternating current side winding 610 into a target pulse current through the rectifier circuit 620, and then inverts the target pulse current into a second alternating current consistent with the alternating current waveform of the power grid through the inverter circuit 630. The switching tube included in the rectifier circuit 620 can be a switching tube with consistent conduction direction, and therefore, the control logic of the third topology circuit in the embodiment is relatively simple and easy to implement.

[0200] In the drawings of the embodiments of the present disclosure, DC represents a direct current side power supply, and AC represents a power grid.

[0201] Please refer to FIG. 8. The direct current side of the third topology circuit provided in the embodiment includes a direct current side winding 640, an inverter H-bridge circuit 650, and a direct current side capacitor C5. The direct current side capacitor C5 is connected to a direct current bus. The first end of the inverter H-bridge circuit 650 is connected in parallel with the direct current side capacitor C5. The second end of the inverter H-bridge circuit 650 is connected to the direct current side winding 640. The direct current side winding 640 and the alternating current side winding 610 are respectively connected to two ends of a transformer.

[0202] The inverter H-bridge circuit 650 is used to convert the direct current output by the direct current power supply into high-frequency alternating current, which is transmitted to the alternating current side winding 610 through the direct current side winding 640.

[0203] In an exemplary embodiment, the rectifier circuit 620 includes a bridge rectifier circuit 621 and a filter capacitor C6, wherein a first end of the bridge rectifier circuit 621 is connected with the alternating current side winding 610, a second end of the bridge rectifier circuit 621 is connected with the filter capacitor C6 in parallel, the bridge rectifier circuit 621 is used to convert the first alternating current into an initial pulsating current, and the filter capacitor C6 is used to filter the initial pulsating current to obtain a target pulsating current; a first end of the flip-flop circuit 630 is connected with the filter capacitor C6 in parallel.

[0204] The filter capacitor C6 filters out the high-frequency ripples in the initial pulsating current and outputs the target pulsating current with a smooth waveform.

[0205] The filter capacitor C6 only needs to filter out the high-frequency ripples in the initial pulsating current, and does not need to filter the initial pulsating current into a direct current with a constant amplitude, so the filter capacitor C6 in the embodiment can use a capacitor with a smaller capacitance value.

[0206] In a possible implementation, the capacitance value of the filter capacitor C6 ranges from 1uF (microfarad) to 10uF.

[0207] For example, the specific capacitance value of the filter capacitor C6 can be determined according to the working power of the third topology circuit and the switching frequency of the bridge rectifier circuit. For example, the switching frequency of the bridge rectifier circuit ranges from 80KHz to 200KHz.

[0208] In a possible implementation, the filter capacitor C6 uses a film capacitor. The film capacitor is a capacitor made of plastic film (such as polyester, polypropylene) as dielectric and metalized or foil electrodes, which has the characteristics of high reliability and low loss. In the third topology circuit provided in the embodiment, the filter capacitor C6 is implemented by using a film capacitor, which reduces the hardware cost of the filter capacitor C6 and improves the circuit reliability and product life.

[0209] In an exemplary embodiment, based on the embodiment shown in FIG. 11, in the third topology circuit provided, please refer to FIG. 12, the bridge rectifier circuit 621 includes a half-bridge rectifier circuit, a first resonant capacitor C7 and a second resonant capacitor C8. Please refer to FIG. 12, a first end of the half-bridge rectifier circuit is connected with the alternating current side winding 610, a second end of the half-bridge rectifier circuit is connected with the filter capacitor C6 in parallel, the half-bridge rectifier circuit includes a first switch tube T Z1 and a second switch tube T Z2 , the first switch tube T Z1 and the second switch tube T Z2The conduction direction of the first switch tube T Z1 The conduction direction of the first switch tube T Z2 Correspondingly.

[0210] The source of the first switch tube T Z1 The drain of the first switch tube T Z1 The second end of the first resonant capacitor C7 is connected with the second end of the AC side winding 610, the first end of the second resonant capacitor C8 is connected with the second end of the AC side winding 610, and the second end of the second resonant capacitor C8 is connected with the source of the second switch tube T Z2 The drain of the second switch tube T Z2 The gate of the first switch tube T Z1 The gate of the second switch tube T Z2 The gate of the first switch tube T Z1 The gate of the second switch tube T Z2 The gate of the second switch tube T

[0211] It should be noted that in the third topology circuit example shown in FIG. 12, the DC side includes a plurality of inverter H-bridge circuits 650 and a plurality of DC side windings 640, and correspondingly, the number of AC side windings 610 is also a plurality. In this example, for the rectifier circuit, the first end and the second end of the AC side winding 610 are the first end and the second end of the AC side winding as a whole after the plurality of AC side windings 610 are connected in series.

[0212] The first resonant capacitor C7 and the leakage inductance of the AC side winding 610 form a resonant cavity for providing a resonant current for the soft switching control of the first switch tube T Z1 The second resonant capacitor C8 and the leakage inductance of the AC side winding 610 form another resonant cavity for providing a resonant current for the soft switching control of the second switch tube T Z2 The second resonant capacitor C8 and the leakage inductance of the AC side winding 610 form another resonant cavity for providing a resonant current for the soft switching control of the second switch tube T

[0213] In a possible implementation, the first resonant capacitor C7 and the second resonant capacitor C8 can be implemented by connecting a plurality of capacitors with small capacitance in parallel. For example, the first resonant capacitor C7 includes eight 22nF ceramic capacitors connected in parallel, and the second resonant capacitor C8 includes eight 22nF ceramic capacitors connected in parallel. In this implementation, the first resonant capacitor C7 and the second resonant capacitor C8 are implemented by connecting a plurality of capacitors with small capacitance in parallel, which can reduce the equivalent series resistance and inductance, improve the high-frequency characteristics, suppress high-frequency noise, and can also disperse the arrangement of multiple small capacitors to avoid local overheating.

[0214] In a possible implementation of the embodiment, a resonant inductor is included in the bridge rectifier circuit, and the resonant inductor, together with a leakage inductance of the AC-side winding 610, a first resonant capacitor C7, and a second resonant capacitor C8, forms a resonant cavity in the bridge rectifier circuit.

[0215] In an example embodiment, based on the embodiment shown in FIG. 11, a third topology circuit is provided, as shown in FIG. 13. The bridge rectifier circuit includes a third resonant capacitor C9 and an H-bridge rectifier circuit. The first end of the H-bridge rectifier circuit is connected to the AC-side winding through the third resonant capacitor C9, and the second end of the H-bridge rectifier circuit is connected in parallel to the filter capacitor C6. As shown in FIG. 8, the H-bridge rectifier circuit includes a third switch tube T Z3 , a fourth switch tube T Z4 , a fifth switch tube T Z5 , and a sixth switch tube T Z6 . The third switch tube T Z3 , the fourth switch tube T Z4 , the fifth switch tube T Z5 , and the sixth switch tube T Z6 have the same conduction direction. The H-bridge rectifier circuit is used to convert the first AC current into an initial pulsating current.

[0216] For example, as shown in FIG. 13, the first bridge arm of the H-bridge rectifier circuit includes the third switch tube T Z3 and the fourth switch tube T Z4 , and the midpoint of the first bridge arm of the H-bridge rectifier circuit is connected to the first end of the AC-side winding 610. The second bridge arm of the H-bridge rectifier circuit includes the fifth switch tube T Z5 and the sixth switch tube T Z6 , and the midpoint of the second bridge arm of the H-bridge rectifier circuit is connected to the second end of the third resonant capacitor C9. The first end of the third resonant capacitor C9 is connected to the second end of the AC-side winding 610.

[0217] It should be noted that in the example of the third topology circuit shown in FIG. 8, the DC side includes a plurality of inverter H-bridge circuits 650 and a plurality of DC-side windings 640. Correspondingly, the number of AC-side windings 610 is also a plurality. In this example, for the rectifier circuit, the first end and the second end of the AC-side winding 610 are the first end and the second end of the AC-side winding as a whole after the plurality of AC-side windings 610 are connected in series.

[0218] In other examples of the embodiment, the third resonant capacitor C9 can be arranged between the bridge arm midpoint of the first bridge arm of the H-bridge rectifier circuit and the first end of the AC-side winding.

[0219] The third resonant capacitor C9 and the leakage inductance of the AC-side winding 610 form a resonant cavity, and the soft switching control of the switch tubes in the H-bridge rectifier circuit provides a resonant current, thereby reducing the switching loss of the H-bridge rectifier circuit.

[0220] In the embodiment, the rectifier circuit 620 is implemented based on an H-bridge rectifier circuit, one resonance cavity is provided to provide the resonance current required by soft switching, and a resonance capacitor with a small capacitance value can be used.

[0221] In a possible implementation, the third resonance capacitor C9 can be implemented by connecting a plurality of capacitors with small capacitance values in parallel. For example, the third resonance capacitor C9 includes seven 22-nF ceramic capacitors connected in parallel.

[0222] In a possible implementation of the embodiment, the bridge rectifier circuit includes a resonance inductor, the resonance inductor and the leakage inductance of the AC-side winding 610 and the third resonance capacitor C9 form a resonance cavity in the bridge rectifier circuit.

[0223] In an example embodiment, referring to FIGS. 12 and 13, the inverter circuit 630 includes an H-bridge inverter circuit. The first bridge arm of the H-bridge inverter circuit includes a seventh switch tube T U1 and an eighth switch tube T U2 , and the second bridge arm of the H-bridge inverter circuit includes a ninth switch tube T U3 and a tenth switch tube T U4 . The H-bridge inverter circuit is used to invert the target pulsating current in the form of a steamed bun wave into a second AC current in the form of a sine wave.

[0224] Referring to FIG. 8, the source of the seventh switch tube T U1 , the source of the ninth switch tube T U3 , the drain of the eighth switch tube T U2 , and the drain of the tenth switch tube T U4 are used as the first end of the H-bridge inverter circuit, and the midpoints of the two bridge arms are used as the second end of the H-bridge inverter circuit.

[0225] In an example embodiment, still referring to FIGS. 12 and 13, the AC side of the third topology circuit further includes a filter circuit 660. The second end of the inverter circuit 630 is connected to the first end of the filter circuit 660, and the second end of the filter circuit 660 is used to be connected to the power grid. The filter circuit 600 is used to reduce the high-frequency common-mode interference between the third topology circuit and the power grid.

[0226] In a possible implementation, the filter circuit 660 includes a common-mode inductor.

[0227] In an exemplary embodiment, the direct current side of the third topology circuit provided includes a direct current side capacitor C5, a plurality of inverter H-bridge circuits 650, and a plurality of direct current side windings 640, and the number of alternating current side windings 610 is a plurality; wherein the plurality of inverter H-bridge circuits 650 are connected in parallel to both ends of the direct current side capacitor C5; the plurality of inverter H-bridge circuits 650 are connected in one-to-one correspondence with the plurality of direct current side windings 640, and the plurality of alternating current side windings 610 are connected in series to the rectifier circuit 620.

[0228] Please refer to FIG. 7 and FIG. 8, for the convenience of display, the circuit structure of the third topology circuit provided in this embodiment is described by taking an example of the direct current side of the third topology circuit including 2 inverter H-bridge circuits 650, 2 direct current side windings 640, and the corresponding alternating current side including 2 alternating current side windings 610. In this example, the direct current side capacitor is capacitor C5; the first bridge arm of the first inverter H-bridge circuit 650 includes switch tube T 11 and switch tube T 12 , the second bridge arm of the first inverter H-bridge circuit 650 includes switch tube T 13 and switch tube T 14 , the midpoint of switch tube T 11 and switch tube T 12 , and the midpoint of switch tube T 13 and switch tube T 14 as the interface of the first inverter H-bridge circuit 650, connected to the direct current side winding 640 in the transformer TS1; the first bridge arm of the second inverter H-bridge circuit 650 includes switch tube T 21 and switch tube T 22 , the second bridge arm of the second inverter H-bridge circuit 650 includes switch tube T 23 and switch tube T 24 , the midpoint of switch tube T 21 and switch tube T 22 , and the midpoint of switch tube T 23 and switch tube T 24 as the interface of the second inverter H-bridge circuit 650, connected to the direct current side winding 640 in the transformer TS2; the two alternating current side windings 610 are connected in series to the first end of the rectifier circuit 620.

[0229] In this embodiment, the direct current side of the third topology circuit includes a plurality of parallel inverter H-bridge circuits 650, so that in the case of a large current value corresponding to the direct current side of the third topology circuit, the current is shared by the plurality of inverter H-bridge circuits 650, so that a single inverter H-bridge circuit 650 can correspondingly bear a smaller current, reducing the complexity of loss control and thermal design of the switch tube in the inverter H-bridge circuit 650, and being suitable for various power conversion scenarios including low-voltage and large-current direct current sides.

[0230] In an exemplary embodiment, referring to FIG. 7 and FIG. 8, a third topology circuit provided by the application includes a DC side capacitor C5, a plurality of inverter H-bridge circuits 650, and a plurality of DC side windings 640, and an AC side including a plurality of AC side windings 610, a rectifier circuit 620, an H-bridge flip circuit, and a filter circuit 660; the plurality of inverter H-bridge circuits 650 are connected in parallel to both ends of the DC side capacitor C5; the plurality of inverter H-bridge circuits 650 are connected one-to-one with the plurality of DC side windings 640; the plurality of AC side windings 610 are connected in series to the first end of the rectifier circuit 620; the second end of the rectifier circuit 620 is connected to the first end of the flip circuit 630, the second end of the flip circuit 630 is connected to the first end of the filter circuit 660, and the second end of the filter circuit 660 is used to connect to the power grid.

[0231] The rectifier circuit 620 includes a bridge rectifier circuit and a filter capacitor C6, the second end of the bridge rectifier circuit is connected in parallel to the filter capacitor C6, and the first end of the H-bridge flip circuit is connected in parallel to the filter capacitor C6. The bridge rectifier circuit is used to convert the first AC circuit into an initial pulsating current, the filter capacitor C6 is used to filter the initial pulsating current to obtain a target pulsating current, and the H-bridge flip circuit is used to flip the target pulsating current into a second AC current.

[0232] The capacitance of the filter capacitor C6 is less than or equal to 10nF, and the filter capacitor C6 is a film capacitor.

[0233] Optionally, referring to FIG. 12, the bridge rectifier circuit includes a half-bridge rectifier circuit, a first resonant capacitor C7, and a second resonant capacitor C8, wherein the first end of the half-bridge rectifier circuit is connected to the AC side winding 610, the second end of the half-bridge rectifier circuit is connected in parallel to the filter capacitor C6, and the half-bridge rectifier circuit includes a first switch tube T Z1 and a second switch tube T Z2 , the conduction directions of the first switch tube T Z1 and the second switch tube T Z2 are the same; the first resonant capacitor C7 corresponds to the first switch tube T Z1 , and the second resonant capacitor C8 corresponds to the second switch tube T Z2 .

[0234] Optionally, the bridge rectifier circuit includes a third resonant capacitor C9 and an H-bridge rectifier circuit; the first end of the H-bridge rectifier circuit is connected to the AC side winding through the third resonant capacitor C9, the second end of the H-bridge rectifier circuit is connected in parallel to the filter capacitor C6, and the H-bridge rectifier circuit includes a third switch tube T Z3 , a fourth switch tube T Z4 , a fifth switch tube T Z5 , and a sixth switch tube T Z6 , the third switch tube T Z3 , the fourth switch tube T Z4 , the fifth switch tube TZ5 and the sixth switch tube T Z6 are in the same conduction direction.

[0235] The first bridge arm of the H-bridge flip-flop circuit includes a seventh switch tube T U1 and an eighth switch tube T U2 The second bridge arm of the H-bridge flip-flop circuit includes a ninth switch tube T U3 and a tenth switch tube T U4 .

[0236] In the third topology circuit, the switch tubes in the direct current side can be selected from switch tubes with a voltage resistance of 40V, 80V or 100V, such as si MOS (Silicon Metal-Oxide-Semiconductor), GaN (Gallium Nitrid) or Sicmos (Silicon Carbide Metal-Oxide-Semiconductor). The switch tubes in the alternating current side of the third topology circuit can be selected from switch tubes with a voltage resistance of 600V or 650V, such as si MOS, GaN, Sicmos or IGBT (Insulated Gate Bipolar Transistor).

[0237] In an exemplary embodiment, the direct current alternating current conversion circuit includes a control circuit. The control circuit is configured to control the alternating current phases of the three single-phase conversion circuits to have a phase difference when the second ends of the three single-phase conversion circuits are not short-circuited, and control the alternating current phases of the three single-phase conversion circuits to be consistent when the first ends of the single-phase conversion circuits are direct current output ends and the second ends of the three single-phase conversion circuits are short-circuited.

[0238] When the first ends of the single-phase conversion circuits are direct current output ends, the direct current alternating current conversion circuit is applied to a scenario in which an energy storage device or other direct current device accesses an alternating current power grid, which can also be referred to as an off-grid scenario. In the off-grid scenario, when the alternating current power grid is a single-phase alternating current power grid, i.e., the second ends of the three single-phase conversion circuits are short-circuited, the controller controls the alternating current phases of the three single-phase conversion circuits to be consistent; when the alternating current power grid is a single-phase alternating current power grid, i.e., the second ends of the three single-phase conversion circuits are not short-circuited, the control circuit is configured to control the alternating current phases of the three single-phase conversion circuits to have a phase difference, and optionally, the control circuit is configured to control the alternating current phases of the three single-phase conversion circuits to have a phase difference of 120 degrees between any two of the alternating current phases.

[0239] In the case that the first end of the single-phase conversion circuit is a direct current input end, the direct current alternating current conversion circuit is applied to the scenario of integrating an energy storage device or other direct current device into an alternating current power grid, which can also be referred to as a grid-connected scenario. In the grid-connected scenario, in the case that the alternating current power grid is a single-phase alternating current power grid, the alternating current side voltage of the direct current alternating current conversion circuit automatically follows the grid voltage, and the alternating current phases of the three single-phase conversion circuits are automatically synchronized, that is, in the case that the second ends of the three single-phase conversion circuits are short-circuited in the grid-connected scenario, the alternating current phases of the three single-phase conversion circuits are automatically consistent. In the grid-connected scenario, in the case that the alternating current power grid is a three-phase alternating current power grid, that is, the second ends of the three single-phase conversion circuits are not short-circuited, the control circuit is used to control the alternating current phases of the three single-phase conversion circuits to have a phase difference, and optionally, the control circuit is used to control the alternating current phases of the three single-phase conversion circuits to have a phase difference of 120 degrees between each other. In an exemplary embodiment, referring to FIG. 14, the control circuit includes a first control circuit 700 and three second control circuits 800. The three second control circuits 800 are respectively in communication connection with the three single-phase conversion circuits 100, and the first control circuit 700 is respectively in communication connection with the three second control circuits 800.

[0240] For example, the first control circuit can be located in a microcontroller unit (MCU) in a battery management system (BMS). The second control circuit can be located in an MCU in a power conversion system (PCS).

[0241] In a possible implementation, the second control circuit 800 is a separate control circuit of the single-phase conversion circuit 100 and is in communication connection with the first control circuit 700. The second control circuit 800 is used to sample input electrical signals and output electrical signals of the single-phase conversion circuit 100, and based on the input sampled electrical signals and the output sampled electrical signals, to obtain the switching frequency of each switch tube in the single-phase conversion circuit 100, the duty cycle corresponding to each switch tube, the outer phase shift angle and the inner phase shift angle. In the implementation, one second control circuit 800 is separately used for each single-phase conversion circuit 100, and the first control circuit 700 communicates with each second control circuit 800 and an external host computer 900.

[0242] For example, the first control circuit 700 and the second control circuit 800 can be integrated on the circuit substrate 300, and the communication lines between the first control circuit 700 and the second control circuit 800 and the communication lines between the second control circuit 800 and the single-phase conversion circuit 100 can be realized through wiring on the circuit substrate 300, without the need for complex external wiring, thereby reducing cost and improving reliability. For example, the MCU of the BMS and the MCU of the PCS are integrated on the circuit substrate 300.

[0243] Please continue to refer to FIG. 13, in a possible implementation, the three second control circuits 800 are connected in communication with each other. Any one of the three second control circuits 800 can serve as a master control circuit, and the other two serve as slave control circuits. In this implementation, the first control circuit 700 can be used only to implement power scheduling among the three single-phase conversion circuits.

[0244] In an exemplary embodiment, please refer to FIG. 15, the control circuit includes the first control circuit 700 and the second control circuit 800. The second control circuit 800 is connected in communication with the three single-phase conversion circuits 100 respectively, and the first control circuit 700 is connected in communication with the second control circuit 800. One of the second control circuits 800 can control the three single-phase conversion circuits 100. The first control circuit 700 communicates with the second control circuit 800 and an external host computer.

[0245] In this embodiment, the three single-phase conversion circuits 100 share one second control circuit 800. Thus, compared with the corresponding embodiment of FIG. 14, the direct-current alternating-current conversion circuit provided in this embodiment can save two second control circuits 800, saving the circuit hardware cost and chip area occupation.

[0246] For example, in the embodiments shown in FIG. 14 and FIG. 15, the communication protocol adopted between the first control circuit 700 and the second control circuit 800 includes one or more of CAN (Controller Area Network), SCI (Serial Communication Interface), SPI (Serial Peripheral Interface), and IIC (Inter-Integrated Circuit).

[0247] In an exemplary embodiment, please refer to FIG. 2 and FIG. 3, the direct-current alternating-current conversion circuit includes a circuit substrate 300, and the three single-phase conversion circuits 100 are arranged on the circuit substrate 300. Thus, the three single-phase conversion circuits 100 are integrated on the same circuit substrate 300.

[0248] In a possible implementation, the direct-current alternating-current conversion circuit includes a control circuit arranged on a circuit substrate, and the control circuit is connected in communication with the three single-phase conversion circuits 100. The communication line can be realized through the wiring on the circuit substrate 300, without the need for complex external wiring, thus being low in cost and high in reliability.

[0249] In a possible implementation, the control circuit includes the first control circuit 700 and three second control circuits 800, and the first control circuit 700 and the three second control circuits 800 are arranged on the circuit substrate 300. The communication lines between the three second control circuits 800 and the first control circuit 700 and the communication lines between the three single-phase conversion circuits 100 can be realized by the wirings on the circuit substrate 300.

[0250] In a possible implementation, the control circuit includes the first control circuit 700 and the second control circuit 800, and the first control circuit 700 and the three second control circuits 800 are arranged on the circuit substrate 300. The communication lines between the three second control circuits 800 and the first control circuit 700 and the communication lines between the three single-phase conversion circuits 100 can be realized by the wirings on the circuit substrate 300.

[0251] In the three implementations, the communication lines between the control circuit and the three single-phase conversion circuits are realized by the wirings on the circuit substrate 300, the communication distance is short, the communication speed is faster, the integration degree is high, external wiring and external interference are avoided, and the processing and production are facilitated.

[0252] In a possible implementation, referring to FIG. 2, the direct-current alternating-current conversion circuit includes an alternating-current terminal arranged on the circuit substrate 300, and the connection lines between the alternating-current terminal and the second ends of the single-phase conversion circuits 100 can be realized by the wirings on the circuit substrate 300, thereby improving the communication reliability of the entire circuit.

[0253] In a possible implementation, the direct-current alternating-current conversion circuit includes a direct-current bus 500 arranged on the circuit substrate 300. The direct-current bus 500 can be realized by the metal wirings of the circuit substrate 300. For example, the direct-current bus 500 can be a metal plate, such as a copper plate, connected to the circuit substrate 300. The end of the direct-current bus 500 connected to the single-phase conversion circuits 100 is provided with only one positive electrode and one negative electrode, and is connected to the first ends of the three single-phase conversion circuits 100.

[0254] In a possible implementation, referring to FIG. 2 and FIG. 3, the direct-current alternating-current conversion circuit includes a bus capacitor C1 connected in parallel to the direct-current bus 500. The connection lines between the direct-current bus 500, the bus capacitor C1 and the single-phase conversion circuits 100 can be realized by the wirings on the circuit substrate 300.

[0255] Referring to FIG. 16, a short-circuit element 400 is provided in an embodiment of the disclosure and is arranged in the power distribution terminal 200.

[0256] Referring to FIG. 17, with reference to a first direction, a second direction and a third direction perpendicular to each other, the first direction is the insertion direction of the short-circuit element 400 relative to the power distribution terminal 200, and the first direction can also be the vertical direction. The second direction and the third direction are both horizontal directions. The first direction, the second direction and the third direction can be understood as the extension directions of the three coordinate axes in a spatial rectangular coordinate system, for example, the first direction is the Z-axis direction, the second direction is the Y-axis direction, and the third direction is the X-axis direction. The short-circuit element 400 includes a switching unit 410 and a mounting unit 420. The switching unit 410 includes a pressing portion 411 and a switching portion 412. The switching portion 412 is protrudingly arranged on the pressing portion 411 along the first direction. The size of the pressing portion 411 along the second direction is greater than the size of the switching portion 412. The mounting unit 420 is arranged on the switching portion 412. The plurality of mounting units 420 are spaced apart along the third direction. The plurality of mounting units 420 are in conductive connection. For example, the end of the plurality of mounting units 420 can be connected with the conductive structure. The switching unit 410 can be connected with the conductive structure by injection molding. In this way, the plurality of mounting units 420 are in conductive connection. When the short-circuit element 400 is inserted into the power distribution terminal 200, the plurality of mounting units 420 are in conductive connection. In this way, the short-circuit element 400 can convert the multi-phase power supplied by the power distribution terminal 200 into single-phase power output. For example, the short-circuit element 400 can convert the three-phase power supplied by the power distribution terminal 200 into single-phase power output.

[0257] Referring to FIG. 16, the short-circuit hole 210 is arranged on the outer surface 230 of the power distribution terminal 200. The short-circuit hole 210 extends along the first direction for a certain length. Obviously, the short-circuit hole 210 penetrates the outer surface 230 of the power distribution terminal 200, so that the short-circuit hole 210 has an opening on the outer surface 230. The number of the short-circuit hole 210 corresponds to the number of the mounting unit 420. The number of the short-circuit hole 210 can be equal to or an integer multiple of the number of the mounting unit 420. When the short-circuit element 400 is inserted into the power distribution terminal 200, different mounting units 420 will be inserted into different short-circuit holes 210. In this way, different mounting units 420 are matched with different short-circuit holes 210. Since the size of the pressing portion 411 along the second direction is greater than the size of the switching portion 412, the pressing portion 411 will abut against the outer surface 230 of the power distribution terminal 200 along the first direction. That is, the pressing portion 411 cannot be inserted into the short-circuit hole 210 of the power distribution terminal, so that the pressing portion 411 is located outside the short-circuit hole 210 and is hung on the outer surface 230 of the power distribution terminal 200.

[0258] If the mode that the size of the abutting portion along the second direction is equal to the size of the adapter portion is adopted, so that the adapter unit is substantially linear, there will be the following defects: first, the linear adapter unit will be entirely accommodated in the short-circuit hole, that is, the adapter unit is located below the outer surface of the power distribution terminal, so that the adapter unit interferes and rubs between the inner walls of the short-circuit hole during assembly, which is not conducive to applying force to the adapter unit, thereby affecting the assembly efficiency of the short-circuit element. Second, the size of the abutting portion of the linear adapter unit along the second direction is small, which can be understood as the abutting portion is narrow. During the assembly of the short-circuit element relative to the power distribution terminal, the force receiving area of the abutting portion is small, which is not conducive to applying force to the abutting portion, thereby affecting the assembly efficiency of the short-circuit element. Third, the power distribution terminal cannot limit the linear adapter unit along the first direction, so that the insertion position of the short-circuit element in the short-circuit hole cannot be accurately grasped, thereby affecting the assembly precision of the short-circuit element. Fourth, since the linear adapter unit will be entirely accommodated in the short-circuit hole and located below the outer surface of the power distribution terminal, during the disassembly process of taking out the short-circuit element from the power distribution terminal, the disassembly tool such as a bolt knife will have difficulty applying force to the adapter unit along the first direction, so that it is difficult to take out the adapter unit from the short-circuit hole along the first direction, thereby affecting the disassembly efficiency of the short-circuit element.

[0259] Referring to FIG. 16, and for the short-circuiting element 400 in the above embodiment, in view of the mode that the dimension of the abutting portion 411 along the second direction is greater than the dimension of the adapter portion 412, so that the adapter unit 410 is substantially T-shaped, there will be the following advantages: first, the abutting portion 411 is located outside the short-circuiting hole 210 and is hung on the outer surface 230 of the power distribution terminal 200, so that interference and friction between the abutting portion 411 and the inner wall surface of the short-circuiting hole 210 can be effectively avoided, thereby facilitating the application of force to the adapter unit 410, and ultimately improving the assembly efficiency of the short-circuiting element 400. Second, the dimension of the abutting portion 411 of the T-shaped adapter unit 410 along the second direction is relatively large, i.e., the abutting portion 411 is wide, thereby reasonably increasing the stress area of the abutting portion 411 and improving the convenience of applying force to the abutting portion 411, thereby improving the assembly efficiency of the short-circuiting element 400. Third, in view of the fact that the abutting portion 411 of the T-shaped adapter unit 410 will be hung on the outer surface 230 of the power distribution terminal 200, i.e., the outer surface 230 of the power distribution terminal 200 will well limit the entire short-circuiting element 400 along the first direction, thereby accurately controlling the insertion position of the short-circuiting element 400 in the short-circuiting hole 210, thereby improving the assembly precision of the short-circuiting element 400. Fourth, in view of the fact that the abutting portion 411 of the T-shaped adapter unit 410 will be hung on the outer surface 230 of the power distribution terminal 200, during the process of taking out the short-circuiting element 400 from the power distribution terminal 200 to realize disassembly, the abutting portion 411 can well serve as the stress fulcrum of the disassembly tool such as a screwdriver, thereby facilitating the disassembly tool to apply force to the short-circuiting element 400 along the first direction, ensuring that the short-circuiting element 400 is smoothly taken out of the short-circuiting hole 210, and thereby improving the disassembly efficiency of the short-circuiting element 400.

[0260] Referring to FIG. 19, in some embodiments, along the second direction, the spacing H between the adapter portion 412 and the end of the abutting portion 411 is 2 mm to 3 mm. For example, the specific value of the spacing H between the adapter portion 412 and the end of the abutting portion 411 can be 2 mm, 2.5 mm, or 3 mm, etc. In this way, the abutting portion 411 has a reasonable length along the second direction and abuts against the outer surface 230 of the power distribution terminal 200, thereby improving the stability and reliability of the abutting portion 411 hung on the power distribution terminal 200, and thereby improving the assembly precision of the short-circuiting element 400. Also, the abutting portion 411 has a large enough stress area, thereby improving the assembly efficiency of the short-circuiting element 400.

[0261] Referring to FIG. 18, in some embodiments, a groove 4121 is recessed on the outer side of the adapter 412, and the groove 4121 is arranged close to the abutting portion 411, so that the groove 4121 and the abutting portion 411 maintain a small distance in the first direction. In the process of disassembling the short-circuit element 400, a disassembling tool such as a screwdriver can be inserted into the groove 4121, and the groove 4121 can well limit the disassembling tool, so as to facilitate the application of the force in the first direction to the short-circuit element 400 in the first direction through the groove 4121, thereby improving the disassembly efficiency of the short-circuit element 400.

[0262] Referring to FIG. 18, in some embodiments, the two ends of the groove 4121 are spaced apart from the edges of the adapter 412 in the second direction by a certain distance, so that the groove 4121 can limit the disassembling tool such as a screwdriver in the second direction, and ensure that the disassembling tool is always located in the groove 4121, avoiding the disassembling tool from being separated from the groove 4121, and also ensuring the disassembly efficiency of the short-circuit element 400. The width A of the groove 4121 is 1.5 mm to 2.5 mm, for example, the width A of the groove 4121 can be 1.5 mm, 2 mm or 2.5 mm, etc. The width A of the groove 4121 can be understood as the size of the groove 4121 in the first direction, so that the groove 4121 has a reasonable width, ensuring that the disassembling tool such as a screwdriver can be smoothly inserted into the groove 4121, thereby improving the disassembly efficiency of the short-circuit element 400.

[0263] Referring to FIG. 17, in some embodiments, the adapter unit 410 is an insulator, so as to avoid the short-circuit element 400 from generating electric leakage, thereby ensuring the safety of the short-circuit element 400. The mounting unit 420 is a conductor, so that the multiple mounting units 420 can be electrically connected in conduction, thereby realizing the short-circuit function and ensuring that the multi-phase electricity is smoothly converted into single-phase electricity by the short-circuit element 400.

[0264] Referring to FIG. 17, in some embodiments, the mounting unit 420 includes a support portion 421 and two edge elastic sheets 422. The support portion 421 is inserted into the adapter 412, and the edge elastic sheets 422 are arranged on the support portion 421 in the first direction. The support portion 421 well bears the edge elastic sheets 422, and the two edge elastic sheets 422 are arranged in the second direction. In the process of inserting the mounting unit 420 into the short-circuit hole 210, the distance between the two edge elastic sheets 422 can be reasonably reduced, thereby reducing the assembly resistance and improving the assembly efficiency. After the short-circuit element 400 is assembled, the two edge elastic sheets 422 with a reasonably reduced distance can generate a reasonable abutting force with the inner side wall of the short-circuit hole 210, thereby improving the stability and reliability of the assembly of the short-circuit element 400.

[0265] Referring to FIG. 17, in some embodiments, the mounting unit 420 comprises an intermediate elastic sheet 423 and two edge elastic sheets 422, the intermediate elastic sheet 423 is arranged between the two edge elastic sheets 422 in the second direction, and the intermediate elastic sheet 423 and the two edge elastic sheets 422 are connected at one end close to the adapter unit 410, for example, the intermediate elastic sheet 423 and the two edge elastic sheets 422 can be arranged on the support portion 421 in the first direction, so that the intermediate elastic sheet 423 and the two edge elastic sheets 422 are connected to each other at one end close to the adapter unit 410 through the intermediate connection of the support portion 421. By arranging the intermediate elastic sheet 423, the structural strength of the mounting unit 420 can be reasonably improved, and the stability and reliability of the assembly of the short-circuit element 400 can be improved to a certain extent.

[0266] Referring to FIG. 19, in some embodiments, the outer side of the edge elastic sheet 422 in the second direction comprises a first connecting section 4221 and a second connecting section 4222, the end portions of the first connecting section 4221 and the second connecting section 4222 are connected to each other, and the second connecting section 4222 is connected to the end face on the free end of the edge elastic sheet 422, which is perpendicular to the first direction. During the insertion process of the short-circuit element 400, it can be understood that the first connecting section 4221 is located above the second connecting section 4222. In the first direction from the adapter unit 410 to the mounting unit 420, that is, in the direction from top to bottom, the distance from the first connecting section 4221 to the intermediate elastic sheet 423 is equal, the distance from the second connecting section 4222 to the intermediate elastic sheet 423 decreases, and the distance from the first connecting section 4221 to the intermediate elastic sheet 423 is greater than the distance from the second connecting section 4222 to the intermediate elastic sheet 423. In this way, the part of the edge elastic sheet 422 at the second connecting section 4222 is roughly wedge-shaped. Therefore, during the insertion process, the wedge-shaped part of the edge elastic sheet 422 can play a good guiding role, reducing the interference resistance of the mounting unit 420 during the insertion process, thereby improving the assembly efficiency of the short-circuit element 400. After the short-circuit element 400 is assembled, the edge elastic sheet 422 can move a certain distance close to the intermediate elastic sheet 423, so that there is a reasonable elastic abutting force between the first connecting section 4221 and the inner side wall surface of the short-circuit hole 210, thereby reasonably improving the fitting force between the short-circuit element 400 and the short-circuit hole 210, avoiding the short-circuit element 400 from being separated from the short-circuit hole 210, thereby improving the stability and reliability of the assembly of the short-circuit element 400.

[0267] Referring to FIG. 19, in some embodiments, the outer side surface further comprises a third connecting segment 4223, the first connecting segment 4221 is connected between the third connecting segment 4223 and the second connecting segment 4222, and it can be understood that the third connecting segment 4223 is located above the first connecting segment 4221 during the insertion of the short-circuiting element 400. The distance from the first connecting segment 4221 to the intermediate elastic sheet 423 is greater than the distance from the third connecting segment 4223 to the intermediate elastic sheet 423, and the distance from the third connecting segment 423 to the intermediate elastic sheet 423 increases in the first direction from the adapter unit 410 to the mounting unit 420, i.e., in the direction from top to bottom. Therefore, by providing the third connecting segment 4223, the third connecting segment 4223 can be spaced apart from the inner side wall surface of the short-circuiting hole 210 during the insertion, so that the contact area between the edge elastic sheet 422 and the inner side wall surface of the short-circuiting hole 210 can be reasonably reduced, thereby reducing the friction and assembly resistance, and thus improving the assembly efficiency of the short-circuiting element 400.

[0268] Referring to FIG. 17, in some embodiments, the edge elastic sheet 422 is provided with a through hole 424, and the through hole 424 penetrates the edge elastic sheet 422 in the second direction. By providing the through hole 424, the weight and material consumption of the edge elastic sheet 422 can be reduced, thereby reducing the material cost of the edge elastic sheet 422, and in turn reducing the manufacturing cost of the short-circuiting element 400. The contact area between the edge elastic sheet 422 and the inner side wall surface of the short-circuiting hole 210 can also be reasonably reduced, thereby reducing the assembly resistance and improving the assembly efficiency. The intermediate elastic sheet 423 can also be provided with a through hole 424, and the through hole 424 penetrates the intermediate elastic sheet 423 in the second direction. In this way, the weight and material consumption of the intermediate elastic sheet 423 can be reduced, thereby reducing the material cost of the intermediate elastic sheet 423, and in turn reducing the manufacturing cost of the short-circuiting element 400.

[0269] Referring to FIG. 20, in some embodiments, the outer surface 230 of the power distribution terminal 200 is provided with a plurality of short-circuiting holes 210, and the short-circuiting holes 210 extend a certain length in the first direction. Obviously, the short-circuiting holes 210 penetrate the outer surface 230, so that the short-circuiting holes 210 have openings on the outer surface 230. A plurality of mounting units 420 are respectively inserted into different short-circuiting holes 210, and the pressing portion 411 abuts against the outer surface 230 of the power distribution terminal 200. By abutting the pressing portion 411 against the outer surface 230 of the power distribution terminal 200, the assembly and disassembly efficiency between the short-circuiting element 400 and the power distribution terminal 200 can be improved, i.e., the disassembly and assembly efficiency is improved.

[0270] Referring to FIG. 20, in some embodiments, the power distribution terminal 200 is provided with a plurality of terminal holes 220 arranged in multiple rows on the power distribution terminal 200, each row including a plurality of live terminal holes 220a for cooperating with live wires and a neutral terminal hole 220b for cooperating with a neutral wire. It is to be noted that each row can also include a ground terminal hole. In this way, multiple live rows can be formed on the power distribution terminal 200, thereby improving the adaptability of the energy storage inverter 10 to various working conditions.

[0271] Referring to FIG. 20, in some embodiments, the shorting holes 210 are located between adjacent two rows of terminal holes 220. In this way, the limited installation space on the power distribution terminal 200 can be fully utilized, and the layout between the shorting holes 210 and the terminal holes 220 can be made more reasonable. The shorting holes 210 can be arranged in multiple rows, and the power distribution terminal 200 includes a partition wall 240 that simultaneously defines the boundaries of two adjacent shorting holes 210 in adjacent two rows, and the thickness of the partition wall 240 is less than a specified value, so that the partition wall 240 has a smaller thickness. By arranging the partition wall 240, the partition wall 240 can abut the edge spring 422 of the mounting unit 420 in the second direction, so that the partition wall 240 can effectively limit the movement of the mounting unit 420 in the second direction, thereby improving the stability and reliability of the assembly of the shorting element 400. For example, the shorting holes 210 can be arranged in two rows, so that two shorting elements 400 can be arranged on the power distribution terminal 200, thereby reasonably increasing the number of shorting elements 400, and when two power distribution terminals 200 each provided with two rows of shorting holes 210 are used simultaneously, three shorting elements 400 can be provided, the first shorting element 400 can be inserted into the shorting holes 210 of one of the power distribution terminals 200, the second shorting element 400 can be inserted into the shorting holes 210 of the other power distribution terminal 200, and the third shorting element 400 can be inserted into the shorting holes 210 of both power distribution terminals 200 at the same time. In this way, the multi-phase power on the two power distribution terminals 200 can be converted into single-phase power output through the three shorting elements 400, thereby improving the adaptability of the energy storage inverter 10 to various working conditions. In other embodiments, the shorting holes 210 can be arranged in more than two rows, thereby further increasing the number of shorting elements 400 and the adaptability of the energy storage inverter 10 to various working conditions.

[0272] Referring to FIG. 20, in some embodiments, the power distribution terminal 200 includes a first single-board interface 221, a second single-board interface 222, a third single-board interface 223, and a fourth single-board interface 224, the first single-board interface 221, the second single-board interface 222, and the third single-board interface 223 are live wire holes 220a, and the fourth single-board interface 224 is a zero wire hole 220b. It can be understood that a row of wiring holes 220 includes the first single-board interface 221, the second single-board interface 222, the third single-board interface 223, and the fourth single-board interface 224. The shorting hole 210 includes a first power distribution interface 211, a second power distribution interface 212, a third power distribution interface 213, and a fourth power distribution interface 214; in the case of shorting the first power distribution interface 211, the second power distribution interface 212, and the third power distribution interface 213, the phases of the first power distribution interface 211, the second power distribution interface 212, and the third power distribution interface 213 are consistent, so as to realize the shorting element 400 to convert multi-phase power into single-phase power.

[0273] The present disclosure also provides an energy storage conversion device 1000, which includes the direct-current alternating-current conversion circuit provided by the foregoing embodiments.

[0274] In some embodiments, the energy storage converter 1000 comprises three single-phase conversion circuits, a power distribution terminal 200 (see FIG. 20) and a short-circuit element 400 (see FIG. 16). The first end of the single-phase conversion circuit 100 is a direct current end, the second end of the single-phase conversion circuit 100 is an alternating current end, and the single-phase conversion circuit 100 is used for mutual conversion between direct current and single-phase alternating current. When the second ends of the three single-phase conversion circuits 100 are short-circuited by the short-circuit element 400, the alternating current phases of the three single-phase conversion circuits 100 are consistent, and when the second ends of the three single-phase conversion circuits 100 are not short-circuited, there is a phase difference between the alternating current phases of the three single-phase conversion circuits 100. The short-circuit element 400 is used to be inserted in the power distribution terminal, the insertion direction of the short-circuit element 400 is defined as the first direction, and the first direction, the second direction and the third direction are perpendicular to each other, and the short-circuit element 400 comprises: a switching unit 410 comprising a switching part 412 and a pressing part 411, the switching part 412 is protrudingly arranged on the pressing part 411 along the first direction, and the size of the pressing part 411 along the second direction is greater than the size of the switching part 412; a mounting unit 420, the number of which is multiple, the multiple mounting units 420 are arranged on the switching part 412 along the third direction, and the multiple mounting units 420 are connected in conduction; the outer surface 230 of the power distribution terminal 200 is provided with multiple short-circuit holes 210, the short-circuit holes 210 extend a certain length along the first direction, and obviously the short-circuit holes 210 penetrate the outer surface 230, so that the short-circuit holes 210 have openings on the outer surface 230. The multiple mounting units 420 are respectively inserted in different short-circuit holes 210, and the pressing part 411 abuts against the outer surface 230 of the power distribution terminal 200. By using the above-mentioned energy storage converter 1000, when the second ends of the three single-phase conversion circuits 100 are short-circuited by the short-circuit element, the alternating current phases of the three single-phase conversion circuits 100 are consistent, so that the direct current alternating current conversion circuit as a whole is used for conversion between single-phase alternating current and direct current; when the second ends of the three single-phase conversion circuits 100 are not short-circuited, there is a phase difference between the alternating current phases of the three single-phase conversion circuits, so that the direct current alternating current conversion circuit as a whole is used for conversion between three-phase alternating current and direct current. In this way, the above-mentioned energy storage converter 1000 can be compatible with three-phase power grid and single-phase power grid, so that the energy storage equipment using the energy storage converter has better flexibility when connected to the grid.

[0275] By using the above-mentioned energy storage converter, by abutting the pressing part 411 against the outer surface 230 of the power distribution terminal 200, the assembly and disassembly efficiency between the short-circuit element 400 and the power distribution terminal 200 can be improved, that is, the disassembly efficiency is improved.

[0276] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as there is no conflict, any combination of the technical features should be considered within the scope of the present disclosure.

[0277] The above-described embodiments only express several implementation manners of the present disclosure, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A DC-AC conversion circuit, wherein, The direct-current alternating-current conversion circuit comprises: three single-phase conversion circuits, a first end of the single-phase conversion circuit being a direct-current end, a second end of the single-phase conversion circuit being an alternating-current end, the single-phase conversion circuit being used for mutual conversion between direct-current and single-phase alternating-current; in the case where the second ends of the three single-phase conversion circuits are short-circuited, the alternating-current phases of the three single-phase conversion circuits are consistent, and in the case where the second ends of the three single-phase conversion circuits are not short-circuited, the alternating-current phases of the three single-phase conversion circuits have a phase difference.

2. The dc-ac conversion circuit of claim 1, wherein, in the case where the second ends of the three single-phase conversion circuits are not short-circuited, the alternating-current phases of the three single-phase conversion circuits have a phase difference of 120 degrees between any two of the three single-phase conversion circuits.

3. The dc-ac conversion circuit according to claim 1 or 2, wherein the first end of the single-phase conversion circuit is a direct-current input end, the second end of the single-phase conversion circuit is an alternating-current output end, and the single-phase conversion circuit is used for converting input direct-current into single-phase alternating-current.

4. The dc-ac conversion circuit according to claim 1 or 2, wherein the first end of the single-phase conversion circuit is a direct-current output end, the second end of the single-phase conversion circuit is an alternating-current input end, and the single-phase conversion circuit is used for converting input alternating-current into direct-current.

5. The dc-ac conversion circuit according to any one of claims 1 to 4, wherein, The direct-current alternating-current conversion circuit comprises: an alternating-current terminal, the alternating-current terminal comprising a first phase interface, a second phase interface, a third phase interface and a zero line interface, wherein the live wires in the second ends of the three single-phase conversion circuits are connected to the first phase interface, the second phase interface and the third phase interface respectively, and the zero lines in the second ends of the three single-phase conversion circuits are connected to the zero line interface; in the case where the first phase interface, the second phase interface and the third phase interface are short-circuited, the alternating-current phases of the three single-phase conversion circuits are consistent.

6. The dc-ac conversion circuit according to any one of claims 1 to 5, wherein, The direct-current alternating-current conversion circuit comprises: a power distribution terminal, the power distribution terminal comprising a first single board interface, a second single board interface, a third single board interface and a fourth single board interface, wherein the first single board interface is connected to the first phase interface, the second single board interface is connected to the second phase interface, the third single board interface is connected to the third phase interface, and the fourth single board interface is connected to the zero line interface; the power distribution terminal comprises a first power distribution interface, a second power distribution interface, a third power distribution interface and a fourth power distribution interface; in the case where the first power distribution interface, the second power distribution interface and the third power distribution interface are short-circuited, the output phases of the three single-phase conversion circuits are consistent.

7. The dc-ac conversion circuit according to any one of claims 1 to 6, wherein, The direct-current alternating-current conversion circuit comprises: a short-circuit element for short-circuiting the first power distribution interface, the second power distribution interface and the third power distribution interface.

8. The dc-ac conversion circuit of claim 7, wherein, The short-circuit element is used for being inserted in the power distribution terminal, the insertion direction of the short-circuit element is defined as a first direction, the first direction, a second direction and a third direction are perpendicular to each other, and the short-circuit element comprises: a switching unit comprising a switching part and a pressing part, the switching part is protrusively arranged on the pressing part along the first direction, and the size of the pressing part along the second direction is greater than the size of the switching part; a plurality of mounting units, the plurality of mounting units are arranged on the switching part along the third direction, and the plurality of mounting units are conductively connected.

9. The dc-ac conversion circuit of claim 8, wherein, The distance between the adapter and the end of the pressing part in the second direction is 2-3 mm.

10. The dc-ac conversion circuit according to claim 8 or 9, wherein The adapter is recessed with a groove at a position close to the pressing part.

11. The dc-ac conversion circuit of claim 10, wherein, The distance between the two ends of the groove and the edge of the adapter is set; and / or, the width of the groove is 1.5-2.5 mm.

12. A dc-ac conversion circuit according to any one of claims 8-11, wherein, The adapter unit is an insulator, and the mounting unit is a conductor, and / or; The plurality of mounting units are connected by a conductive structure.

13. The dc-ac conversion circuit according to any one of claims 8-12, wherein, The mounting unit includes a support part and two edge springs, the support part is inserted into the adapter, the edge spring is protrudingly arranged on the support part along the first direction, and the two edge springs are arranged at intervals along the second direction.

14. The dc-ac conversion circuit according to any one of claims 8-12, wherein, The mounting unit includes an intermediate spring and two edge springs, the intermediate spring is arranged at intervals between the two edge springs, and the intermediate spring and the two edge springs are connected at one end close to the adapter unit.

15. The dc-ac conversion circuit of claim 14, wherein, The outer side of the edge spring in the second direction includes a first connecting segment and a second connecting segment connected at the end, the second connecting segment is connected with the end face of the free end of the edge spring perpendicular to the first direction, the distance from the first connecting segment to the intermediate spring is greater than the distance from the second connecting segment to the intermediate spring, and along the first direction from the adapter unit to the mounting unit, the distance from the first connecting segment to the intermediate spring is equal, and the distance from the second connecting segment to the intermediate spring decreases.

16. The dc-ac conversion circuit of claim 15, wherein, The outer side further includes a third connecting segment, the first connecting segment is connected between the third connecting segment and the second connecting segment, the distance from the first connecting segment to the intermediate spring is greater than the distance from the third connecting segment to the intermediate spring, and along the first direction from the adapter unit to the mounting unit, the distance from the third connecting segment to the intermediate spring increases.

17. A dc-ac conversion circuit according to any one of claims 14-16, wherein, Through holes are arranged on the intermediate spring and the edge spring, and the through holes penetrate the intermediate spring and the edge spring along the second direction.

18. A dc-ac conversion circuit according to any one of claims 8-16, wherein, The outer surface of the power distribution terminal is recessed with a plurality of short-circuit holes, a plurality of mounting units are respectively inserted into different short-circuit holes, and the pressing part is in abutment with the outer surface of the power distribution terminal.

19. A dc-ac conversion circuit according to any one of claims 6-18, wherein, The power distribution terminal is provided with a plurality of wiring holes, and the plurality of wiring holes are arranged to form a plurality of rows on the power distribution terminal, each row includes a plurality of live wire holes and a zero wire hole, the live wire hole is used for cooperating with the live wire, and the zero wire hole is used for cooperating with the zero wire.

20. The dc-ac conversion circuit of claim 18 or 19, wherein, The short-circuit hole is located between the two adjacent rows of wiring holes.

21. A dc-ac conversion circuit according to any one of claims 18-20, wherein, The short-circuit holes are arranged to form a plurality of rows, and the power distribution terminal includes a spacing wall which simultaneously defines the boundaries of two adjacent short-circuit holes arranged in adjacent two rows, and the thickness of the spacing wall is less than a set value.

22. A dc-ac conversion circuit according to any one of claims 18-21, wherein, The first single board interface, the second single board interface and the third single board interface are live wire holes, and the fourth single board interface is a zero wire hole; And / or; The short-circuit hole includes the first power distribution interface, the second power distribution interface, the third power distribution interface and the fourth power distribution interface.

23. The dc-ac conversion circuit according to any one of claims 1-22, wherein, The direct-current alternating-current conversion circuit includes: A direct-current bus; The first ends of the three single-phase conversion circuits are connected in parallel to the DC bus; The DC bus is configured to combine at least one initial DC input current into a target DC input current, or to combine initial DC output currents of the three single-phase conversion circuits into a target DC output current.

24. The dc-ac conversion circuit of claim 23, wherein, The DC-AC conversion circuit comprises: A bus capacitor connected in parallel to the DC bus.

25. A dc-ac conversion circuit according to claim 23 or 24, wherein, The DC-AC conversion circuit comprises a first inductive element; The first end of the first inductive element is connected to the DC bus, and the second end of the first inductive element is configured to be connected to an external DC circuit.

26. A dc-ac conversion circuit according to any one of claims 23-25, wherein, The DC-AC conversion circuit comprises at least two second inductive elements; one of the second inductive elements corresponds to one of the single-phase conversion circuits, the first end of the second inductive element is connected to the first end of the corresponding single-phase conversion circuit, and the second end of the second inductive element is connected to the DC bus.

27. The dc-ac conversion circuit according to any one of claims 1-26, wherein, The single-phase conversion circuit comprises a first topology circuit; The first topology circuit comprises a DC side capacitor, a plurality of H-bridge circuits, a plurality of DC side windings, a plurality of AC side windings, and a secondary side circuit, wherein The plurality of H-bridge circuits are connected in parallel to both ends of the DC side capacitor; The plurality of H-bridge circuits are connected one by one to the plurality of DC side windings; The plurality of AC side windings are connected in series to the secondary side circuit.

28. A dc-ac conversion circuit according to any one of claims 1-26, wherein, The single-phase conversion circuit comprises a second topology circuit; The second topology circuit comprises a DC side capacitor, an H-bridge circuit, a DC side winding, an AC side winding, and a secondary side circuit, wherein The H-bridge circuit is connected to both ends of the DC side capacitor; The H-bridge circuit is connected to the DC side winding; The AC side winding is connected to the secondary side circuit.

29. A dc-ac conversion circuit according to any one of claims 1-27, wherein, The single-phase conversion circuit comprises a plurality of first topology circuits; The plurality of first topology circuits are connected in parallel.

30. The dc-ac conversion circuit according to any one of claims 1-29, wherein, The single-phase conversion circuit comprises a second topology circuit; The second topology circuit has a circuit topology different from that of the first topology circuit; The first topology circuit and the second topology circuit are connected in parallel.

31. The dc-ac conversion circuit according to any one of claims 1-26, wherein, The single-phase conversion circuit comprises a third topology circuit; The AC side of the third topology circuit comprises an AC side winding, a rectifier circuit, and a flip circuit; The first end of the rectifier circuit is connected to the AC side winding, the second end of the rectifier circuit is connected to the first end of the flip circuit, and the rectifier circuit is configured to convert a first AC current into a target pulsating current; The second end of the flip circuit is configured to be connected to a power grid, and the flip circuit is configured to convert the target pulsating current into a second AC current.

32. The dc-ac conversion circuit of claim 31, wherein, The rectifier circuit comprises a bridge rectifier circuit and a filter capacitor, wherein The first end of the bridge rectifier circuit is connected to the AC side winding, the second end of the bridge rectifier circuit is connected in parallel to the filter capacitor, the bridge rectifier circuit is configured to convert the first AC current into an initial pulsating current, and the filter capacitor is configured to filter the initial pulsating current to obtain the target pulsating current; The first end of the flip circuit is connected in parallel to the filter capacitor.

33. The dc-ac conversion circuit of claim 32, wherein, The capacitance of the filter capacitor ranges from 1 microfarad to 10 microfarad.

34. A dc-ac conversion circuit according to claim 32 or 33, wherein, The filter capacitor is a thin film capacitor.

35. A dc-ac conversion circuit according to any one of claims 32-34 wherein, The bridge rectifier circuit comprises a half-bridge rectifier circuit, a first resonant capacitor and a second resonant capacitor, wherein The first end of the half-bridge rectifier circuit is connected with the AC side winding, the second end of the half-bridge rectifier circuit is connected with the filter capacitor in parallel, the half-bridge rectifier circuit comprises a first switch tube and a second switch tube, and the conduction directions of the first switch tube and the second switch tube are the same. The first resonant capacitor corresponds to the first switch tube, and the second resonant capacitor corresponds to the second switch tube.

36. A dc-ac conversion circuit according to any one of claims 32-34, wherein, The bridge rectifier circuit comprises a third resonant capacitor and an H-bridge rectifier circuit. The first end of the H-bridge rectifier circuit is connected with the AC side winding through the third resonant capacitor, the second end of the H-bridge rectifier circuit is connected with the filter capacitor in parallel, the H-bridge rectifier circuit comprises a third switch tube, a fourth switch tube, a fifth switch tube and a sixth switch tube, and the conduction directions of the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are the same.

37. A dc-ac conversion circuit according to any one of claims 31-36 wherein, The flip circuit comprises an H-bridge flip circuit, wherein The first bridge arm of the H-bridge flip circuit comprises a seventh switch tube and an eighth switch tube, and the second bridge arm of the H-bridge flip circuit comprises a ninth switch tube and a tenth switch tube.

38. A dc-ac conversion circuit according to any one of claims 31-37 wherein, The AC side of the third topology circuit further comprises a filter circuit; The second end of the flip circuit is connected with the first end of the filter circuit; The second end of the filter circuit is used for being connected to a power grid.

39. A dc-ac conversion circuit according to any one of claims 31-38 wherein, The DC side of the third topology circuit comprises a DC side capacitor, a plurality of inverter H-bridge circuits and a plurality of DC side windings, and the number of the AC side windings is a plurality. The plurality of inverter H-bridge circuits are connected in parallel to both ends of the DC side capacitor. The plurality of inverter H-bridge circuits are connected in one-to-one correspondence with the plurality of DC side windings. The plurality of AC side windings are connected in series to the rectifier circuit.

40. The dc-ac conversion circuit of any one of claims 1-39, wherein, The DC-AC conversion circuit comprises: The control circuit is used for controlling the AC phases of the three single-phase conversion circuits to have a phase difference in the case that the second ends of the three single-phase conversion circuits are not short-circuited, and controlling the AC phases of the three single-phase conversion circuits to be consistent in the case that the first ends of the single-phase conversion circuits are DC output ends and the second ends of the three single-phase conversion circuits are short-circuited.

41. The dc-ac conversion circuit of claim 40, wherein, The control circuit comprises a first control circuit and three second control circuits, wherein The three second control circuits are respectively connected in communication with the three single-phase conversion circuits. The first control circuit is respectively connected in communication with the three second control circuits.

42. The dc-ac conversion circuit of claim 40, wherein, The control circuit comprises a first control circuit and a second control circuit. The second control circuit is respectively connected in communication with the three single-phase conversion circuits. The first control circuit is connected in communication with the second control circuit.

43. The dc-ac conversion circuit of any one of claims 1-42, wherein, The DC-AC conversion circuit comprises a circuit substrate. The three single-phase conversion circuits are arranged on the circuit substrate.

44. An energy storage conversion device, wherein, The DC-AC conversion circuit comprises a circuit substrate. The DC-AC conversion circuit comprises a circuit substrate.

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