CN217486182U - Energy storage system structure for alternating current power grid interconnection - Google Patents
Energy storage system structure for alternating current power grid interconnection Download PDFInfo
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- CN217486182U CN217486182U CN202220763578.2U CN202220763578U CN217486182U CN 217486182 U CN217486182 U CN 217486182U CN 202220763578 U CN202220763578 U CN 202220763578U CN 217486182 U CN217486182 U CN 217486182U
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Abstract
The utility model discloses an energy storage system structure is used in alternating current electric wire netting interconnection, include: an energy storage battery unit; the alternating current side of the first DC/AC converter equipment is connected with a first alternating current power grid, and the positive electrode and the negative electrode of the direct current side of the first DC/AC converter equipment are respectively connected with the positive electrode and the negative electrode of the energy storage battery unit; and the alternating current side of the second DC/AC converter equipment is connected with a second alternating current power grid, and the positive electrode and the negative electrode of the direct current side of the second DC/AC converter equipment are respectively connected with the positive electrode and the negative electrode of the energy storage battery unit. By adopting the technical scheme, different alternating current power grids can be asynchronously interconnected through energy storage, and the flexibility of alternating current power exchange at two sides is improved.
Description
Technical Field
The utility model belongs to the technical field of energy storage DC AC converter, concretely relates to energy storage system structure is used in alternating current network interconnection.
Background
The existing connection between ac grids is divided into ac and dc connections. The alternating current connection mode is that two power grids are directly connected through an alternating current transmission line, and the power grids of the alternating current connection mode have many problems such as synchronous stability and the like, generally need to adopt unified scheduling, and the control flexibility of two sides is poor. The direct current connection mode generally refers to a flexible direct current or conventional direct current connection mode, although the operation control of the alternating current power grids on two sides can be decoupled, the current manufacturing cost is high, more investment can be increased, and meanwhile, the larger occupied area is the control complexity.
Therefore, a new ac grid connection mode needs to be researched to realize friendly interconnection of different ac grids and increase flexibility of ac current power exchange on two sides.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem of friendly interconnection of alternating current power grids, the application provides an energy storage system structure for interconnection of alternating current power grids, different alternating current power grids can be asynchronously interconnected through energy storage, and the flexibility of alternating current power exchange on two sides is improved.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
the application provides an energy storage system structure for alternating current network interconnection, include:
an energy storage battery unit;
the alternating current side of the first DC/AC converter equipment is connected with a first alternating current power grid, and the positive and negative poles of the direct current side of the first DC/AC converter equipment are respectively connected with the positive and negative poles of the energy storage battery unit;
and the alternating current side of the second DC/AC converter equipment is connected with a second alternating current power grid, and the positive and negative poles of the direct current side of the second DC/AC converter equipment are respectively connected with the positive and negative poles of the energy storage battery unit.
Preferably, the first DC/AC converter device comprises at least one DC/AC converter, the second DC/AC converter device comprises at least one DC/AC converter, and the energy storage battery unit comprises at least one energy storage battery pack; the number of the DC/AC converters in the first DC/AC converter device and the second DC/AC converter device is equal to the number of the energy storage battery packs in the energy storage battery unit.
Preferably, the energy storage system structure for AC power grid interconnection includes at least two groups of the energy storage battery units, at least two groups of the second DC/AC converter devices, and at least two groups of the first switches, where the first DC/AC converter devices are respectively connected to the at least two groups of the energy storage battery units through the at least two groups of the first switches, and the at least two groups of the second DC/AC converter devices are respectively connected to the at least two groups of the energy storage battery units; the number of the switches of each group of first switches is equal to the number of the energy storage battery packs in the energy storage battery unit.
Preferably, the energy storage system structure for AC power grid interconnection includes at least two groups of the energy storage battery units, at least two groups of the second DC/AC converter devices, and at least two groups of the second switches, where the first DC/AC converter device is directly connected to the at least two groups of the energy storage battery units, and the at least two groups of the second DC/AC converter devices are correspondingly connected to the at least two groups of the energy storage battery units through the at least two groups of the second switches, respectively; the number of the switches of each group of second switches is equal to the number of the energy storage battery packs in the energy storage battery unit.
Preferably, the energy storage system structure for alternating current power grid interconnection comprises at least two groups of energy storage battery units, at least two groups of second DC/AC converter devices, at least two groups of first switches and at least two groups of second switches, wherein the first DC/AC converter devices are respectively connected with the two groups of energy storage battery units through the at least two groups of first switches, and the at least two groups of second DC/AC converter devices are respectively correspondingly connected with the at least two groups of energy storage battery units through the at least two groups of second switches; the number of the switches of each group of the first switches and the number of the switches of each group of the second switches are equal to the number of the energy storage battery packs in the energy storage battery unit.
Preferably, the energy storage system structure for the alternating current power grid interconnection comprises at least two groups of energy storage battery units, at least two groups of first switches and at least two groups of second switches; the first DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of first switches, and the second DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of second switches; the number of the switches of each group of the first switches and the number of the switches of each group of the second switches are equal to the number of the energy storage battery packs in the energy storage battery unit.
Preferably, the first DC/AC converter device is connected to a first AC power supply system via a transformer, and/or the second DC/AC converter device is connected to a second AC power supply system via a transformer.
Preferably, the first DC/AC converter device and the energy storage battery unit are connected to the energy storage battery unit via a DC/DC converter and/or the second DC/AC converter device and the energy storage battery unit are connected to the energy storage battery via a DC/DC converter.
Preferably, the energy storage cell unit is a chemical battery, a super capacitor or a fuel cell.
The utility model has the advantages that:
1. the utility model discloses a two DC AC converter direct current sides link to each other with the positive negative pole of energy storage battery respectively, and the side of exchanging inserts different alternating current electric wire netting respectively, realizes that different alternating current electric wire netting passes through the asynchronous interconnection of energy storage, can avoid two alternating current electric wire netting to connect the synchronous stability scheduling problem that exists through weak contact channel, and is economic good for the direct current connection scheme.
2. The energy storage can exert the storage electric quantity to the both sides alternating current electric wire netting, promotes the energy storage utilization efficiency.
3. The utility model discloses the scheme can increase the flexibility of both sides alternating current power exchange, and both sides alternating current network can carry out the power exchange according to the demand, realizes that the power is nimble each other to be good at.
Drawings
Fig. 1 is a schematic structural diagram of an energy storage system for ac power grid interconnection provided in embodiment 1 of the present invention;
fig. 2 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 2 of the present invention;
fig. 3 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 3 of the present invention;
fig. 4 is a schematic diagram of a two-level topology structure of a DC/AC converter according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a three-level topology structure of a DC/AC converter provided in an embodiment of the present invention;
fig. 6 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 4 of the present invention;
fig. 7 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 5 of the present invention;
fig. 8 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 6 of the present invention;
fig. 9 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 7 of the present invention;
fig. 10 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 8 of the present invention;
fig. 11 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 9 of the present invention;
fig. 12 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 10 of the present invention;
fig. 13 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 11 of the present invention;
fig. 14 is a schematic structural view of an energy storage system for ac power grid interconnection according to embodiment 12 of the present invention;
fig. 15 is a schematic structural view of an energy storage system for ac power grid interconnection provided in embodiment 13 of the present invention;
fig. 16 is a topology structure of a triple-interleaved cascaded buck/boost bidirectional DC-DC converter according to an embodiment of the present invention;
fig. 17 is a topology structure of a cascaded Buck-boost bidirectional DC-DC converter according to an embodiment of the present invention; fig. 18 is a full-bridge bidirectional DC-DC converter topology according to an embodiment of the present invention;
fig. 19 is a schematic flow chart of a method for controlling the structure of an energy storage system for ac power grid interconnection according to an embodiment of the present invention;
fig. 20 is a schematic flow chart of a method for controlling a structure of an energy storage system for ac power grid interconnection according to an embodiment of the present invention.
Wherein 1-a first alternating current grid, 2-a second alternating current grid, 3-a first DC/AC converter device, 4-a second DC/AC converter device, 5-an energy storage battery unit, 6-a first switch, 7-a second switch, 8-a transformer on the side of the first DC/AC converter device, 9-a transformer on the side of the second DC/AC converter device, 10-a DC/DC converter on the side of the first DC/AC converter device 3, 11-a DC/DC converter on the side of the second DC/AC converter device.
Detailed Description
The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Furthermore, the technical features mentioned in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
The utility model discloses an alternating current network interconnection energy storage system structure, in an embodiment, as shown in FIG. 1, alternating current network interconnection energy storage system structure includes: a first DC/AC converter device 3, a second DC/AC converter device 4 and an energy storage battery unit 5. The AC side of the first DC/AC converter device 3 is connected to the first AC grid 1, and the positive and negative poles of the DC side thereof are connected to the positive and negative poles of the energy storage battery unit 5, respectively. The AC side of the second DC/AC converter device 4 is connected to the second AC power grid 2, and the positive and negative poles of the DC side thereof are connected to the positive and negative poles of the energy storage battery unit 5, respectively. The frequencies of the first ac power network 1 and the second ac power network 2 may or may not be the same. In the embodiment, the direct current sides of the two DC/AC converter devices are respectively connected with the positive electrode and the negative electrode of the energy storage battery, and the alternating current sides are respectively connected into different alternating current power grids, so that the two alternating current power grids can be interconnected through the energy storage battery, the power can be flexibly exchanged through the energy storage system according to the control requirements of the alternating current power grids on the two sides, and the asynchronous interconnection of the alternating current power grids is realized.
Wherein the first DC/AC converter device comprises at least one DC/AC converter, the second DC/AC converter device comprises at least one DC/AC converter, and the energy storage battery unit comprises at least one energy storage battery pack; the number of the DC/AC converters in the first DC/AC converter device and the second DC/AC converter device is equal to the number of the energy storage battery packs in the energy storage battery unit.
In the embodiment, the direct current sides of the two DC/AC converters are respectively connected with the anode and the cathode of the energy storage battery, and the alternating current sides are respectively connected into different alternating current power grids, so that different alternating current power grids are asynchronously interconnected through energy storage, the problems of synchronous stability and the like existing in the connection of the two alternating current power grids through a weak connection channel can be solved, and the direct current connection scheme is economic and good. Moreover, the stored energy can exert the stored electric quantity on the alternating current power grids on the two sides, and the utilization efficiency of the stored energy is improved. The flexibility of power exchange of alternating current on two sides is increased, and power exchange can be performed on alternating current power grids on two sides according to requirements, so that the power is flexible and complementary.
In an AC grid interconnected energy storage system configuration as shown in fig. 2, the first DC/AC converter device 3 comprises a DC/AC converter PCS3-1, the second DC/AC converter device 4 comprises a DC/AC converter PCS4-1, and the energy storage battery unit comprises an energy storage battery pack BAT 5-1. The alternating current measurement of the DC/AC converter PCS3-1 is connected to an alternating current power grid 1, and the positive electrode and the negative electrode of the direct current side of the PCS3-1 are respectively connected with the positive electrode and the negative electrode of an energy storage battery pack BAT 5-1. The alternating current measurement of the DC/AC converter PCS4-1 is connected to an alternating current power grid 2, and the positive electrode and the negative electrode of the direct current side of the PCS4-1 are respectively connected with the positive electrode and the negative electrode of an energy storage battery pack BAT 5-1.
In the structure of the energy storage system for alternating current network interconnection shown in fig. 3, the first DC/AC converter device 3 comprises two DC/AC converters PCS3-1 and PCS3-2, the second DC/AC converter device 4 comprises two DC/AC converters PCS4-1 and PCS4-2, and the energy storage battery unit comprises two energy storage battery packs BAT5-1 and BAT 5-2. Alternating current measurement of the DC/AC converters PCS3-1 and PCS3-2 is connected to an alternating current power grid 1, positive and negative poles of a direct current side of the PCS3-1 are respectively connected with positive and negative poles of the energy storage battery pack BAT5-1, and positive and negative poles of a direct current side of the PCS3-2 are respectively connected with positive and negative poles of the energy storage battery pack BAT 5-2. Alternating current measurement of the DC/AC converters PCS4-1 and PCS4-2 is connected to an alternating current power grid 2, positive and negative poles of a direct current side of the PCS4-1 are respectively connected with positive and negative poles of the energy storage battery pack BAT5-1, and positive and negative poles of a direct current side of the PCS4-2 are respectively connected with positive and negative poles of the energy storage battery pack BAT 5-2.
The DC/AC converter in the energy storage system adopts a voltage source type converter topology based on IGBT to realize the bidirectional energy flow of an alternating current system and a direct current system, and the commonly used topology structures are a two-level topology shown in figure 4 and a three-level topology shown in figure 5.
In some embodiments, the energy storage system structure for AC grid interconnection includes two sets of energy storage battery cells and two sets of second DC/AC converter devices, and a switch may be provided between the first DC/AC converter device and the energy storage battery cells, or between the second DC/AC converter device and the energy storage battery cells, or between the first DC/AC converter device and the energy storage battery cells, and between the second DC/AC converter device and the energy storage battery cells. When the energy storage battery units in operation are unavailable due to faults or SOC (System on chip) out-of-range reasons and the like, the DC/AC converter can be switched to the other group of energy storage battery units through the change-over switch.
The energy storage system architecture for AC grid interconnection in the embodiment shown in fig. 6 comprises a set of first DC/AC converter devices 3, two sets of energy storage cells 5, two sets of second DC/AC converter devices 4 and two sets of first switches 6. The first DC/AC converter device 3 is connected to the two sets of energy storage cells 5 through two sets of first switches 6, respectively, and the two sets of second DC/AC converter devices 4 are correspondingly connected to the two sets of energy storage cells 5, respectively. In this embodiment, the first DC/AC converter device 3 includes two DC/AC converters PCS3-1 and PCS 3-2; each group of energy storage battery units 5 comprises two energy storage battery packs, the first group of energy storage battery units 5 comprise BAT5-1 and BAT5-2, and the second group of energy storage battery units 5 comprise BAT5-3 and BAT 5-4; the first set of second DC/AC converter devices 4 comprises two DC/AC converters PCS4-1 and PCS4-2, the second set of second DC/AC converter devices 4 comprises two DC/AC converters PCS4-3 and PCS 4-4; the first set of first switches 6 comprises switches 6-1 and 6-2 and the second set of first switches 6 comprises switches 6-3 and 6-4. Alternating current measurement of the DC/AC converters PCS3-1 and PCS3-2 is connected to an alternating current power grid 1, the direct current side of the PCS3-1 is connected with an energy storage battery pack BAT5-1 through a switch 6-1 and is connected with an energy storage battery pack BAT5-3 through a switch 6-3, and the direct current side of the PCS3-2 is connected with an energy storage battery pack BAT5-2 through a switch 6-2 and is connected with an energy storage battery pack BAT5-4 through a switch 6-4; alternating current sides of DC/AC converters PCS4-1, PCS4-2, PCS4-3 and PCS4-4 are all connected to an alternating current grid 2, direct sides of two converters PCS4-1 and PCS4-2 of the first group of second DC/AC converter equipment 4 are respectively connected with energy storage battery packs BAT5-1 and BAT5-2, and direct sides of two converters PCS4-3 and PCS4-4 of the second group of second DC/AC converter equipment 4 are respectively connected with energy storage battery packs BAT5-3 and BAT 5-4. Under the condition of normal operation, one of the two groups of first switches 6 is closed to form a passage to be connected to the corresponding energy storage battery unit, and the other group is opened; when the energy storage battery units in operation are unavailable due to reasons such as fault or SOC (state of charge) out-of-range, the on-off states of the two groups of switches are switched, and therefore the system operation is switched to the other group of energy storage battery units. In some embodiments, more energy storage battery units 5, second DC/AC converter devices 4 and first switches 6 may be provided, and the number of the three groups is equal, and the connection modes shown in fig. 6 are correspondingly connected.
The energy storage system architecture for AC grid interconnection in the embodiment shown in fig. 7 also comprises a set of first DC/AC converter devices 3, two sets of energy storage cells 5 and two sets of second DC/AC converter devices 4. The difference to the embodiment shown in fig. 6 is that the first DC/AC converter device 3 is directly connected to two sets of energy storage cells 5, and instead of two sets of first switches 6, two sets of second switches 7 are provided between two sets of energy storage cells 5 and two sets of second DC/AC converter devices 4. The first group of second switches 7 comprises a switch 1-1 and a switch 1-2, the second group of second switches 7 comprises a switch 7-3 and a switch 7-4, the direct current side of the PCS4-1 in the first group of second DC/AC converter devices 4 is connected with the energy storage battery pack BAT5-1 through the switch 7-1, the direct current side of the PCS4-2 is connected with the energy storage battery pack BAT5-2 through the switch 7-2, the direct current side of the PCS4-3 in the second group of second DC/AC converter devices 4 is connected with the energy storage battery pack BAT5-3 through the switch 7-3, the direct current side of the PCS4-4 is connected with the energy storage battery pack BAT5-4 through the switch 7-4, and other parts are similar to the embodiment of FIG. 6 and will not be described again. Under the condition of normal operation, one of the two groups of second switches 7 is closed to form a passage to be connected to the corresponding energy storage battery unit, and the other group is opened; when the energy storage battery unit in operation is unavailable due to reasons such as faults or SOC (state of charge) out-of-range and the like, the on-off states of the two groups of switches are switched, so that the system operation is switched to the other group of energy storage battery unit. In some embodiments, more sets of energy storage battery cells 5, second DC/AC converter devices 4, and second switches 7 may be provided, where the sets of the three are equal, and the three sets are correspondingly connected with each other with reference to the connection manner of fig. 7.
The energy storage system architecture for AC grid interconnection in the embodiment shown in fig. 8 also comprises a set of first DC/AC converter devices 3, two sets of energy storage cells 5, two sets of second DC/AC converter devices 4 and two sets of first switches 6. The difference with the embodiment shown in fig. 6 is that in addition to the first DC/AC converter device 3 being connected to two sets of energy storing cells 5 via two sets of first switches 6, two sets of second switches 7 are provided between two sets of energy storing cells 5 and two sets of second DC/AC converter devices 4. The first group of second switches 7 comprises a switch 1-1 and a switch 1-2, the second group of second switches 7 comprises a switch 7-3 and a switch 7-4, the direct current side of the PCS4-1 in the first group of second DC/AC converter devices 4 is connected with the energy storage battery pack BAT5-1 through the switch 7-1, the direct current side of the PCS4-2 is connected with the energy storage battery pack BAT5-2 through the switch 7-2, the direct current side of the PCS4-3 in the second group of second DC/AC converter devices 4 is connected with the energy storage battery pack BAT5-3 through the switch 7-3, the direct current side of the PCS4-4 is connected with the energy storage battery pack BAT5-4 through the switch 7-4, and other parts are similar to the embodiment of FIG. 6 and will not be described again. Under the condition of normal operation, one of the two groups of first switches 6 is closed, and one of the two corresponding groups of second switches 7 is closed to form a passage to be connected to the corresponding energy storage battery unit, and the other group of first switches 6 and the corresponding second switches 7 are opened; when the running energy storage battery unit is unavailable due to reasons such as fault or SOC out-of-range, the opening and closing states of the two groups of first switches 6 and the two groups of first switches 7 are switched, and therefore the system running is switched to the other group of energy storage battery unit. In some embodiments, more sets of energy storage battery cells 5, second DC/AC converter device 4, first switch 6 and second switch 7 may be provided, where the sets of the four are equal, and the sets are correspondingly connected with reference to the connection manner of fig. 8.
In some embodiments, the energy storage system structure for alternating current grid interconnection comprises at least two groups of the energy storage battery units, at least two groups of first switches and at least two groups of second switches; the first DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of first switches, and the second DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of second switches; the number of switches of each group of first switches and the number of switches of each group of second switches are equal to the number of energy storage battery packs in the energy storage battery unit. As shown in fig. 9, the energy storage system structure for AC grid interconnection includes a set of first DC/AC converter devices 3, a set of second DC/AC converter devices 4, two sets of energy storage battery units 5, two sets of first switches 6, and two sets of second switches 7; the first DC/AC converter equipment 3 is correspondingly connected with the two groups of energy storage battery units 5 through two groups of first switches 6, and the second DC/AC converter equipment 4 is correspondingly connected with the two groups of energy storage battery units 5 through two groups of second switches 7. Specifically, the direct current side of the PCS3-1 is connected with an energy storage battery pack BAT5-1 through a switch 6-1 and is connected with an energy storage battery pack BAT5-3 through a switch 6-3, and the direct current side of the PCS3-2 is connected with an energy storage battery pack BAT5-2 through a switch 6-2 and is connected with an energy storage battery pack BAT5-4 through a switch 6-4; the direct current side of the PCS4-1 is connected with the energy storage battery pack BAT5-1 through the switch 7-1 and connected with the energy storage battery pack BAT5-3 through the switch 7-3, and the direct current side of the PCS4-2 is connected with the energy storage battery pack BAT5-2 through the switch 7-2 and connected with the energy storage battery pack BAT5-4 through the switch 7-4. Under the condition of normal operation, one of the two groups of first switches 6 is closed, and one of the two corresponding groups of second switches 7 is closed to form a passage to be connected to the corresponding energy storage battery unit, and the other group of first switches 6 and the corresponding second switches 7 are opened; when the energy storage battery units in operation are unavailable due to faults or SOC out-of-range reasons and the like, the on-off states of the two groups of first switches 6 and the two groups of first switches 7 are switched, and therefore the operation of the system is switched to the other group of energy storage battery units. In some embodiments, more sets of the energy storage battery unit 5, the first switch 6, and the second switch 7 may be provided, and the sets of the three are equal, and are correspondingly connected with each other in the connection manner shown in fig. 9.
In some embodiments, the first DC/AC converter device is connected to the first AC power grid via a transformer, and/or the second DC/AC converter device is connected to the second AC power grid via a transformer. The embodiment shown in fig. 10 is based on the schematic diagram of fig. 1, in that the AC side of the first DC/AC converter device 3 is connected to the first AC power grid 1 via a transformer 8. The embodiment shown in fig. 11 is based on the schematic diagram of fig. 1, the AC side of the second DC/AC converter device 4 being connected to the second AC power grid 2 via a transformer 9. In the exemplary embodiment shown in fig. 12, on the basis of the schematic diagram of fig. 1, the AC side of the first DC/AC converter device 3 is connected to the first AC power supply system 1 via a transformer 8, while the AC side of the second DC/AC converter device 4 is connected to the second AC power supply system 2 via a transformer 9. In the embodiments of fig. 2, 3 and 6 to 9, the first AC power network 1 may be connected to only the AC side of the first DC/AC converter device 3 via the transformer 8, or the second AC power network 2 may be connected to only the AC side of the second DC/AC converter device 4 via the transformer 9, or the first AC power network 1 may be connected to the AC side of the first DC/AC converter device 3 via the transformer 8 while the second AC power network 2 is connected to the AC side of the second DC/AC converter device 4 via the transformer 9.
In some embodiments, the first DC/AC converter device and the energy storage battery unit are connected to the energy storage battery via a DC/DC converter and/or the second DC/AC converter device and the energy storage battery unit are connected to the energy storage battery via a DC/DC converter. The embodiment shown in fig. 13 is based on the schematic diagram of fig. 1, and the DC side of the first DC/AC converter device 3 is connected to the energy storage cell 5 via the DC/DC converter 10. The embodiment shown in fig. 14 is based on the schematic diagram of fig. 1, and the DC side of the second DC/AC converter device 4 is connected to the energy storage cell 5 via the DC/DC converter 11. In the embodiment shown in fig. 15, on the basis of the schematic diagram of fig. 1, the DC side of the first DC/AC converter device 3 is connected to the energy storage cell 5 via the DC/DC converter 10, while the DC side of the second DC/AC converter device 4 is connected to the energy storage cell 5 via the DC/DC converter 11. In the embodiments of fig. 2, 3, and 6 to 12, the energy storage battery unit 5 may be connected to only the DC side of the first DC/AC converter device 3 through the DC/DC converter 10, or the energy storage battery unit 5 may be connected to only the DC side of the second DC/AC converter device 4 through the DC/DC converter 11, or the energy storage battery unit 5 may be connected to the DC side of the first DC/AC converter device 3 through the DC/DC converter 10 while the energy storage battery unit 5 is connected to the DC side of the second DC/AC converter device 4 through the DC/DC converter 11. The DC-DC converter comprises an isolated type and a non-isolated type, wherein the former comprises but is not limited to a flyback bidirectional DC-DC converter, a forward bidirectional DC-DC converter, a push-pull bidirectional DC-DC converter, a full-bridge bidirectional DC-DC converter and the like, and the latter comprises but is not limited to a Buck/Boost, a Boost/Buck, a Buck-Boost, a Cuk, a Sepic/Zeta, a Zeta/Sepic and the like. Fig. 16 shows a topology of a triple staggered cascade buck/boost bidirectional DC-DC converter. Fig. 17 shows a topology of a cascade Buck-boost bidirectional DC-DC converter. Fig. 18 is a full bridge bidirectional DC-DC converter topology.
In some embodiments, the energy storage cell unit may be a chemical battery, a super capacitor, or a fuel cell.
The embodiment of the utility model provides a control method of alternating current network interconnection energy storage system structure has still been provided. The control method adopts independent control considering current out-of-limit, namely the DC/AC converters in the first DC/AC converter equipment and the second DC/AC converter equipment are independently charged and discharged according to respective alternating current side requirements, and the alternating current side current of the DC/AC converters is subjected to amplitude limiting control when the alternating current side current is out-of-limit. The requirements of the alternating current side include system voltage, frequency and power angle stability.
In some embodiments, in performing amplitude limiting control on the AC side current of the DC/AC converter when the AC side current exceeds a limit, the setting of the amplitude limiting control is determined according to a maximum allowable charging and discharging current fixed value of the DC/AC converter in the first DC/AC converter device and the second DC/AC converter device, a real-time current, a control mode of the DC/AC converter, and a maximum allowable charging and discharging current of the energy storage battery pack in the energy storage battery unit.
In some embodiments, the performing amplitude limiting control on the AC-side current of the DC/AC converter when the AC-side current is out of limit specifically includes, as shown in fig. 19:
s110, setting the maximum allowable charging and discharging current fixed values of the DC/AC converter in the first DC/AC converter equipment and the second DC/AC converter equipment as I set1 And I set2 . For example, the maximum allowable charge-discharge current fixed value of the DC/AC converter PCS3-1 is set to be I in FIG. 2 set1 Setting the maximum allowable charging and discharging current fixed value of the DC/AC converter PCS4-1 as I set2 。
S120, measuring the alternating current side currents of the DC/AC converters in the first DC/AC converter equipment and the second DC/AC converter equipment, and calculating effective values to be I 1 And I 2 . For example, in FIG. 2, the alternating-current side current of the DC/AC converter PCS3-1 is measured, and the effective value I of the alternating-current side current is calculated 1 Measuring the alternating current side current of the DC/AC converter PCS4-1, and calculating the effective value I of the alternating current side current 2 。
S130, setting control modes of DC/AC converters in the first DC/AC converter equipment and the second DC/AC converter equipment, setting one side of the control modes as a main operation mode and setting the other side of the control modes as an auxiliary operation mode; the main operation mode is to control current automatically in priority, and the auxiliary operation mode is to track and calculate required current according to the current of the main operation mode. For example, in FIG. 2, a DC/AC converter PCS3-1 is set to be in a main operation mode, and a DC/AC converter PCS4-1 is set to be in an auxiliary operation mode; or the DC/AC converter PCS3-1 is set to be in an auxiliary operation mode, and the DC/AC converter PCS4-1 is set to be in a main operation mode. In consideration of the supporting performance, the converter connected with the weak alternating current network side is generally selected as a main operation mode.
S140, setting the maximum allowable charging and discharging current I of the energy storage battery pack in the energy storage battery unit setb In which I setb ＞I set1 、I setb ＞I set2 (ii) a For example, in FIG. 2, maximum allowable charging/discharging current of energy storage battery BAT5-1 is set to I setb I setb Need to be greater than I set1 And I set2 。
S150, when the DC/AC converter at the equipment side of the first DC/AC converter is in a main operation mode, the upper limit value of the amplitude limiting control of the alternating current side current is equal to I set1 The DC/AC converter in the second DC/AC converter equipment is in an auxiliary operation mode, and the upper limit value of the amplitude limiting control of the alternating current side of the DC/AC converter equipment is equal to min { I } set2 ，|I setb -I 1 L }; when the DC/AC converter at the equipment side of the second DC/AC converter is in a main operation mode, the upper limit value of the amplitude limiting control of the alternating current side current is equal to I set2 The DC/AC converter in the first DC/AC converter device is in auxiliary operation mode, and the upper limit value of the AC side current amplitude limiting control is equal to min { I } set1 ，|I setb -I 2 And l. For example, when PCS3-1 in FIG. 2 is in the main operation mode, the upper limit value of the AC side current limiting control of PCS3-1 is equal to I set1 The upper limit value of the AC side current limiting control of PCS4-1 is equal to min { I } set2 ，|I setb -I 1 The minimum of the comparison elements is taken in the meaning of min. When PCS4-1 is in the main operation mode, the upper limit value of the alternating current side current amplitude limiting control of PCS4-1 is equal to I set2 The upper limit value of the AC side current limiting control of PCS3-1 is equal to min { I } set1 ，|I setb -I 2 |}。
And S160, when the alternating current side current of the DC/AC converter exceeds the upper limit value of the corresponding alternating current side current amplitude limiting control, carrying out amplitude limiting control on the alternating current side current.
In the embodiment, the independent control considering the current out-of-limit is adopted, the upper limit value of the calculated alternating current side current amplitude limiting control is used as the amplitude limiting input of the current amplitude limiting control of the DC/AC converter, the current limitation is realized, and the current limiting method can effectively cope with the situation that the alternating current of the DC/AC converter or the current of the energy storage battery pack is out-of-limit.
The utility model relates to a control method of energy storage system structure is used in alternating current electric wire netting interconnection that embodiment provided adopts active power to pass through control, and the DC AC converter equipment of energy storage battery unit both sides is not more than under the prerequisite of this side current restriction at the alternating current survey current of both sides all promptly, trails the other side power operation.
In some embodiments, as shown in fig. 20, the tracking the power operation of each other specifically includes:
s210, setting control modes of DC/AC converters in the first DC/AC converter equipment and the second DC/AC converter equipment, setting one side of the control modes as a main operation mode, and setting the other side of the control modes as an auxiliary operation mode; the main operation mode is to control current automatically in priority, and the auxiliary operation mode is to track and calculate required current according to the current of the main operation mode. For example, in fig. 2, the DC/AC converter PCS3-1 is set to be in a main operation mode, and the DC/AC converter PCS4-1 is set to be in an auxiliary operation mode; or the DC/AC converter PCS3-1 is set to be in an auxiliary operation mode, and the DC/AC converter PCS4-1 is set to be in a main operation mode. In consideration of the supporting performance, the converter connected with the weak alternating current network side is generally selected as a main operation mode.
And S220, measuring the alternating current side current of the DC/AC converter in the first DC/AC converter equipment and the second DC/AC converter equipment, and comparing the alternating current side current of the DC/AC converter with the current limit value of the corresponding side. For example, in FIG. 2, the alternating-current side current of the PCS3-1 of the DC/AC converter is measured to obtain an effective value I of the alternating-current side current 1 Measuring the alternating current side current of the DC/AC converter PCS4-1 to obtain an effective value I of the alternating current side current 2 Comparison I 1 And current limit value I of PCS3-1 max1 Of and comparison I 2 And current limit value I of PCS4-1 max2 The size of (d);
and S230, in response to the fact that the current of the alternating current sides of the DC/AC converters on the two sides does not exceed the current limit of the current at the current side, the DC/AC converter in the auxiliary operation mode acquires the real-time power of the DC/AC converter in the main operation mode from the DC/AC converter in the main operation mode, and the real-time power is used as the reference power of the DC/AC converter in the auxiliary operation mode. Example (b)As shown in FIG. 2 as I 1 Is less than or equal to I max1 And I 2 Is less than or equal to I max2 When the PCS3-1 is in a main operation mode and the PCS4-1 is in an auxiliary operation mode, the PCS4-1 obtains real-time power P1 of the PCS3-1 converter from the PCS3-1, and takes P1 as reference power of the PCS 4-1; if the PCS4-1 is in a main operation mode and the PCS3-1 is in an auxiliary operation mode, the PCS3-1 obtains real-time power P2 of the PCS4-1 converter from the PCS4-1, and takes P2 as reference power of the PCS 3-1.
By adopting active power ride-through control, the power exchange between the two alternating current systems is completely realized through energy storage, and the influence on the energy storage battery can be reduced to the minimum.
The embodiment of the utility model provides a Control method of energy storage system structure is used in alternating current electric network interconnection adopts AGC (Automatic Generation Control ) command tracking stack local frequency modulation Control, and DC/AC converter is as this DC/AC converter operating power reference value behind the local frequency modulation power with received AGC power reference value stack promptly. The AGC command is a response scheduling command, and meanwhile, local frequency modulation is superposed, so that on the premise of normally responding to the scheduling command, quick response can be realized after a fault or disturbance occurs, and the frequency stability is improved.
The utility model relates to a Control method of energy storage system structure is used in alternating current electric network interconnection that embodiment provided adopts AVC (Automatic Voltage Control) command tracking stack local reactive compensation Control, and DC/AC converter responds according to the AVC instruction in the Voltage Control blind spot promptly, surpasss behind the blind spot and according to the local closed loop adjustment reactive power of Voltage magnitude on the basis of AVC instruction.
In some embodiments, the reactive power is locally adjusted in a closed loop according to the voltage magnitude, that is, the reactive output is dynamically and continuously adjusted according to the voltage magnitude, specifically, the reactive output is increased when the voltage is reduced, and the reactive output is reduced when the voltage is increased. The AVC reactive voltage control is adopted as steady-state control, the local control mainly responds to the emergency voltage control, and the system voltage stability under the emergency fault can be improved by adopting AVC command tracking and overlaying the local reactive compensation control.
The utility model discloses a control method of energy storage system structure is used in alternating current network interconnection can adopt and consider that current out of limit's independent control, active power pass through control, AGC order track stack local frequency modulation control, AVC order track stack local reactive compensation control in one or several kinds. The DC/AC converters on the two sides can respectively realize the functions of primary frequency modulation, voltage regulation and the like on the accessed power grid, and the power grid is beneficial to stable operation.
The above embodiments are only used for illustrating the technical solution of the present invention and not for limiting the same, and various modifications or changes made with reference to the above embodiments are within the scope of the present invention.
Claims (10)
1. An energy storage system structure for alternating current power grid interconnection, comprising:
an energy storage battery unit;
the alternating current side of the first DC/AC converter equipment is connected with a first alternating current power grid, and the positive electrode and the negative electrode of the direct current side of the first DC/AC converter equipment are respectively connected with the positive electrode and the negative electrode of the energy storage battery unit;
and the alternating current side of the second DC/AC converter equipment is connected with a second alternating current power grid, and the positive electrode and the negative electrode of the direct current side of the second DC/AC converter equipment are respectively connected with the positive electrode and the negative electrode of the energy storage battery unit.
2. The AC power grid interconnected energy storage system architecture of claim 1, wherein said first DC/AC converter device comprises at least one DC/AC converter, said second DC/AC converter device comprises at least one DC/AC converter, said energy storage battery cells comprise at least one energy storage battery pack; the number of the DC/AC converters in the first DC/AC converter device and the second DC/AC converter device is equal to the number of the energy storage battery packs in the energy storage battery unit.
3. The energy storage system structure for interconnection of alternating current networks according to claim 1, comprising at least two groups of said energy storage battery cells, at least two groups of said second DC/AC converter devices and at least two groups of first switches, wherein said first DC/AC converter devices are respectively connected to at least two groups of energy storage battery cells through at least two groups of first switches, and said at least two groups of second DC/AC converter devices are respectively connected to at least two groups of energy storage battery cells; the number of the switches of each group of first switches is equal to the number of the energy storage battery packs in the energy storage battery units.
4. The energy storage system structure for AC power grid interconnection according to claim 1, comprising at least two sets of said energy storage cells, at least two sets of said second DC/AC converter devices, and at least two sets of second switches, wherein said first DC/AC converter device is directly connected to at least two sets of energy storage cells, and said at least two sets of second DC/AC converter devices are respectively connected to at least two sets of energy storage cells through at least two sets of second switches; the number of the switches of each group of second switches is equal to the number of the energy storage battery packs in the energy storage battery units.
5. The energy storage system structure for interconnection of alternating current networks according to claim 1, comprising at least two groups of said energy storage battery cells, at least two groups of said second DC/AC converter devices, at least two groups of first switches, and at least two groups of second switches, wherein said first DC/AC converter devices are respectively connected to two groups of energy storage battery cells through at least two groups of first switches, and said at least two groups of second DC/AC converter devices are respectively connected to at least two groups of energy storage battery cells through at least two groups of second switches; the number of the switches of each group of the first switches and the number of the switches of each group of the second switches are equal to the number of the energy storage battery packs in the energy storage battery unit.
6. The energy storage system structure for alternating current grid interconnection according to claim 1, comprising at least two groups of the energy storage battery cells, at least two groups of first switches, and at least two groups of second switches; the first DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of first switches, and the second DC/AC converter equipment is respectively connected with the two groups of energy storage battery units through at least two groups of second switches; the number of switches of each group of first switches and the number of switches of each group of second switches are equal to the number of energy storage battery packs in the energy storage battery unit.
7. An energy storage system architecture for interconnection of alternating current networks as claimed in any one of claims 1 to 6, wherein the first DC/AC converter device is connected to the first alternating current network via a transformer and/or the second DC/AC converter device is connected to the second alternating current network via a transformer.
8. The energy storage system structure for alternating current power grid interconnection according to any one of claims 1 to 6, wherein the first DC/AC converter device and the energy storage battery unit are connected with the energy storage battery unit through a DC/DC converter and/or the second DC/AC converter device and the energy storage battery unit are connected with the energy storage battery through a DC/DC converter.
9. The energy storage system architecture for AC power grid interconnection of claim 7, wherein said first DC/AC converter device and said energy storage battery unit are connected to the energy storage battery unit through a DC/DC converter and/or said second DC/AC converter device and the energy storage battery unit are connected to the energy storage battery through a DC/DC converter.
10. The energy storage system structure for ac power grid interconnection of claim 1, wherein the energy storage battery cell is a chemical battery, a super capacitor, or a fuel cell.
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