CN220711145U - Parallel-to-off-grid switching circuit of energy storage inverter, energy storage inverter and photovoltaic energy storage system - Google Patents
Parallel-to-off-grid switching circuit of energy storage inverter, energy storage inverter and photovoltaic energy storage system Download PDFInfo
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- CN220711145U CN220711145U CN202322095294.8U CN202322095294U CN220711145U CN 220711145 U CN220711145 U CN 220711145U CN 202322095294 U CN202322095294 U CN 202322095294U CN 220711145 U CN220711145 U CN 220711145U
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Abstract
The utility model relates to a parallel-to-off-grid switching circuit of an energy storage inverter, the energy storage inverter and a photovoltaic energy storage system, wherein the parallel-to-off-grid switching circuit comprises: an energy storage inverter and a plurality of switch units; the energy storage inverter is connected to a first input live wire of the power grid through a first switch unit and a second switch unit which are connected in series, and is connected to a first input zero wire of the power grid through a third switch unit and a fourth switch unit which are connected in series; the energy storage inverter is also connected to a second input live wire of the load through a seventh switching unit and connected to a second input zero wire of the load through an eighth switching unit; the connection point of the first switch unit and the second switch unit is connected with the second input live wire through the fifth switch unit; the connection point of the third switch unit and the fourth switch unit is connected with the second input zero line through the sixth switch unit, so that the problem that the grid-connected and off-grid switching of the energy storage inverter cannot be realized at low cost is solved, and the grid-connected and off-grid switching cost of the energy storage inverter is reduced.
Description
Technical Field
The utility model relates to the technical field of photovoltaic energy storage, in particular to a grid-connected and off-grid switching circuit of an energy storage inverter, the energy storage inverter and a photovoltaic energy storage system.
Background
The photovoltaic power generation system is a power generation system which converts variable direct current voltage generated by a solar panel into alternating current with mains frequency by utilizing photovoltaic effect of a photovoltaic cell. In practical applications, it is often necessary to store the electrical energy generated by the photovoltaic device, where the ac generated by the photovoltaic power generation may be converted into dc by an energy storage inverter, and the electrical energy is stored in a storage battery. And when the electric energy in the storage battery is needed to be used, the energy storage inverter can invert the electric energy into alternating current for loads or power grids.
Because the output end of the energy storage inverter needs to be directly or electrically connected with the power grid and the load through the transformer when electric energy is transmitted, a plurality of groups of relays are required to be connected in series between the output end of the inverter and the input end of the power grid in order to meet the safety requirement, so that the inverter can be disconnected from the power grid quickly and reliably when the system is abnormal. However, in the existing solution, at least 12 relays are set to realize reliable disconnection of the inverter from the power grid, so that a large number of relays are needed to be used, and the parallel off-grid switching of the energy storage inverter cannot be realized at low cost.
Aiming at the problem that the parallel-to-off switching of the energy storage inverter cannot be realized at low cost in the related art, no effective solution is proposed at present.
Disclosure of Invention
Based on this, it is necessary to provide a parallel-to-off network switching circuit of an energy storage inverter, the energy storage inverter and a photovoltaic energy storage system, aiming at the problem that the parallel-to-off network switching of the energy storage inverter cannot be realized at low cost in the prior art.
In a first aspect, the present utility model provides a parallel-to-off-grid switching circuit of an energy storage inverter, the parallel-to-off-grid switching circuit comprising: an energy storage inverter and a plurality of switch units;
the energy storage inverter is connected to a first input live wire of the power grid through a first switch unit and a second switch unit which are connected in series, and is connected to a first input zero wire of the power grid through a third switch unit and a fourth switch unit which are connected in series;
the energy storage inverter is also connected to a second input live wire of the load through a seventh switch unit and connected to a second input zero wire of the load through an eighth switch unit;
the connection point of the first switch unit and the second switch unit is connected to the second input live wire through a fifth switch unit; the connection point of the third switch unit and the fourth switch unit is connected to the second input zero line through a sixth switch unit.
In some of these embodiments, the switching unit is a relay or an ac contactor.
In some embodiments, the off-grid switching circuit further comprises a photovoltaic power supply device connected with the energy storage inverter.
In some embodiments thereof, the photovoltaic power supply device comprises a photovoltaic power generation system and an energy storage battery;
the photovoltaic power generation system and the energy storage battery are connected with the energy storage inverter.
In some embodiments, the connection point of the sixth and seventh switching units is connected to the input ground of the load through a ninth and tenth switching unit connected in series.
In some embodiments thereof, the energy storage inverter is a single-phase energy storage inverter or a three-phase energy storage inverter.
In some embodiments, in the grid-tie mode, the second switch unit, the fourth switch unit, the fifth switch unit, and the sixth switch unit are all in a closed state.
In some embodiments, in off-grid mode, the first, second, third, fourth, fifth, and sixth switching units are all in an off state;
the seventh and eighth switching units are in a closed state.
In a second aspect, the present utility model provides an energy storage inverter comprising a grid-connected switching circuit of the energy storage inverter of any one of the first aspects.
In a third aspect, the present utility model provides a photovoltaic energy storage system comprising a grid, a load and an energy storage inverter as described in any of the first aspects.
Compared with the related art, the parallel-to-off-grid switching circuit of the energy storage inverter, the energy storage inverter and the photovoltaic energy storage system provided by the utility model, wherein the parallel-to-off-grid switching circuit comprises: an energy storage inverter and a plurality of switch units; the energy storage inverter is connected to a first input live wire of the power grid through a first switch unit and a second switch unit which are connected in series, and is connected to a first input zero wire of the power grid through a third switch unit and a fourth switch unit which are connected in series; the energy storage inverter is also connected to a second input live wire of the load through a seventh switching unit and connected to a second input zero wire of the load through an eighth switching unit; the connection point of the first switch unit and the second switch unit is connected with the second input live wire through the fifth switch unit; the connection point of the third switch unit and the fourth switch unit is connected with the second input zero line through the sixth switch unit, so that the problem that the parallel-to-off network switching of the energy storage inverter cannot be realized at low cost is solved, the parallel-to-off network switching cost of the energy storage inverter is reduced, and the reliability of switching control is improved.
The details of one or more embodiments of the utility model are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the other features, objects, and advantages of the present application.
Drawings
Fig. 1 is a block diagram of a parallel-to-off-grid switching circuit of an energy storage inverter according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a photovoltaic power supply device according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a ground connection circuit according to an embodiment of the present application;
fig. 4 is a schematic diagram of an off-grid switching circuit of a single-phase energy storage inverter according to an embodiment of the present disclosure;
fig. 5 is a schematic diagram of an off-grid switching circuit of a three-phase energy storage inverter according to an embodiment of the present disclosure;
fig. 6 is a block diagram of a parallel-to-off-grid switching circuit of an energy storage inverter according to a preferred embodiment of the present application.
Reference numerals: 101. an energy storage inverter; 102. a first switching unit; 103. a second switching unit; 104. a third switching unit; 105. a fourth switching unit; 106. a fifth switching unit; 107. a sixth switching unit; 108. a seventh switching unit; 109. an eighth switching unit; 110. a ninth switching unit; 111. a tenth switching unit; 112. a power grid; 113. a load; 114. a photovoltaic power supply device; 1141. a photovoltaic power generation system; 1142. an energy storage battery.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It is noted that when an element is referred to as being "mounted to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.
Unless defined otherwise, 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 utility model belongs. The terminology used herein in the description of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "or/and" as used herein includes any and all combinations of one or more of the associated listed items.
The utility model provides a parallel-to-off network switching circuit of an energy storage inverter, fig. 1 is a block diagram of a parallel-to-off network switching circuit of an energy storage inverter according to an embodiment of the utility model, as shown in fig. 1, and the parallel-to-off network switching circuit comprises: an energy storage inverter 101 and a plurality of switching units;
the energy storage inverter 101 is connected to a first input live wire of the power grid 112 through a first switch unit 102 and a second switch unit 103 which are connected in series, and is connected to a first input zero wire of the power grid 112 through a third switch unit 104 and a fourth switch unit 105 which are connected in series;
the energy storage inverter 101 is also connected to a second input live line of the load 113 through a seventh switching unit 108, and is connected to a second input neutral line of the load 113 through an eighth switching unit 109;
the connection point of the first switch unit 102 and the second switch unit 103 is connected to the second input live wire through the fifth switch unit 106;
the connection point of the third switching unit 104 and the fourth switching unit 105 is connected to the second input zero line through the sixth switching unit 107.
It should be noted that, in the off-grid switching circuit of the present embodiment, the grid-connected side is connected to the grid 112, the off-grid side is connected to the load 113, and the grid-connected side is connected to the load 113 through the fifth switching unit 106 and the sixth switching unit 107, so that the outputs of the energy storage inverter 101 and the grid 112 can both supply power to the load 113. Wherein, between the energy storage inverter 101 and the grid-connected side, the first input live wire is connected to the power grid 112 through the first switch unit 102 and the second switch unit 103 which are connected in series, and the first input neutral wire is connected to the power grid 112 through the third switch unit 104 and the fourth switch unit 105 which are connected in series; between the energy storage inverter 101 and the off-grid side, it is connected to the second input hot of the load 113 through the seventh switching unit 108, and to the second input neutral of the load 113 through the eighth switching unit 109.
Specifically, when the power grid 112 fails, i.e. cannot supply power to the load 113, the current circuit is switched to the off-grid mode, the first switch unit 102, the second switch unit 103, the third switch unit 104, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 are controlled to be opened, and the seventh switch unit 108 and the eighth switch unit 109 are closed, i.e. are switched to output of the energy storage inverter 101 to supply power to the load 113, so as to realize continuous power transmission to the load 113, and prevent the situation that the load 113 is powered off.
Further, when the power grid 112 is powered, the current circuit is switched to the grid-connected mode, and the second switch unit 103, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 in the circuit are always closed. At this time, the power supply mode to the load 113 is adjusted according to the electric energy output by the energy storage inverter 101, if the electric energy output by the energy storage inverter 101 realizes the spontaneous self-use of photovoltaic power generation, the first switch unit 102 and the third switch unit 104 are controlled to be closed, so that the redundant electric energy can be transmitted to the power grid 112 while the requirement of the load 113 is met; if the energy storage inverter 101 outputs less electric energy and can only bear part of the power supply requirement of the load 113, the electric energy of the load 113 is supplemented by the power grid 112.
When electric energy is transmitted, the output end of the energy storage inverter 101 needs to be directly or electrically connected with the power grid 112 and the load 113 through a transformer, and in order to meet the safety requirement, a plurality of groups of relays are required to be connected in series between the output end of the inverter and the input end of the power grid 112 so as to ensure that the inverter can be disconnected from the power grid 112 quickly and reliably when the system is abnormal. However, in the existing solution, at least 12 relays are provided to realize reliable disconnection of the inverter from the power grid 112, and a large number of relays are required to be used, so that the off-grid switching of the energy storage inverter 101 cannot be realized at low cost. Compared with the prior art, the method and the device have the advantages that when the use safety is improved, only fewer switching units are adopted to realize the off-grid noninductive switching, the uninterrupted power supply requirement of the load 113 is met, the off-grid switching cost of the energy storage inverter 101 is reduced, the probability of circuit faults is further reduced by reducing the number of the switching units, and the reliability of switching control is improved.
The energy storage inverter 101 is connected to a first input live wire of the power grid 112 through a first switch unit 102 and a second switch unit 103 which are connected in series, and is connected to a first input zero wire of the power grid 112 through a third switch unit 104 and a fourth switch unit 105 which are connected in series; the energy storage inverter 101 is also connected to a second input live line of the load 113 through a seventh switching unit 108, and is connected to a second input neutral line of the load 113 through an eighth switching unit 109; the connection point of the first switch unit 102 and the second switch unit 103 is connected with a second input live wire through a fifth switch unit 106; the connection point of the third switch unit 104 and the fourth switch unit 105 is connected with the second input zero line through the sixth switch unit 107, so that the problem that the off-grid switching of the energy storage inverter 101 cannot be realized at low cost is solved, the off-grid switching cost of the energy storage inverter 101 is reduced, and the reliability of switching control is improved.
Furthermore, the connection point of the first switch unit 102 and the second switch unit 103 is connected to the second input live wire through the fifth switch unit 106, the connection point of the third switch unit 104 and the fourth switch unit 105 is connected to the second input zero line through the sixth switch unit 107, and the power grid 112 is connected to the off-grid side through the independent switch units, so that off-grid noninductive switching can be achieved, and the load 113 is prevented from being stopped due to overlong switching time.
In some of these embodiments, the switching unit is a relay or an ac contactor.
Specifically, each of the switching units may be provided as a relay or an ac contactor. The relay and the alternating current contactor are electromagnetic switch devices, and the switch-on and switch-off of the circuit is controlled by controlling the energizing state of the coil to drive the switch-on and switch-off of the contact.
It should be noted that the present embodiment is connected to the first input live line of the power grid 112 through the first switch unit 102 and the second switch unit 103 connected in series, and is connected to the first input neutral line of the power grid 112 through the third switch unit 104 and the fourth switch unit 105 connected in series, so as to improve the use safety.
Through the embodiment, each switch unit adopts a relay or an alternating current contactor, and the switch units between the inverter and the power grid are reasonably arranged while the circuit cost is reduced.
Referring to fig. 2, in some embodiments, the off-grid switching circuit further includes a photovoltaic power supply 114, and the photovoltaic power supply 114 is connected to the energy storage inverter 101.
Specifically, the photovoltaic power supply device 114 is connected to the energy storage inverter 101, and when the photovoltaic power supply device 114 supplies power to the load, the energy storage inverter 101 inverts the electric energy provided by the photovoltaic power supply device 114 into alternating current to be delivered to the load, or delivers redundant electric energy to the power grid for use by the power supply network.
The photovoltaic power supply device 114 includes a photovoltaic power generation system 1141 and an energy storage battery 1142, and the photovoltaic power generation system 1141 and the energy storage battery 1142 are both connected to the energy storage inverter 101. When the circuit is in the off-grid mode, only the seventh switch unit 108 and the eighth switch unit 109 are closed, and the photovoltaic power generation system 1141 and the energy storage battery 1142 provide electric energy to supply power to the load 113; when the circuit is in the grid-connected mode, the second switch unit 103, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 are kept closed all the time, and the load is independently powered by the photovoltaic power supply device 114 or the photovoltaic power supply device 114 and the power grid are jointly powered according to whether the electric energy provided by the photovoltaic power supply device 114 is sufficient.
Through the embodiment, the photovoltaic power supply device 114 is connected with the energy storage inverter 101 and is used for supplying power to the load, so that the power supply mode to the load can be reasonably adjusted when the parallel-to-off network mode is switched.
Referring to fig. 3, in some embodiments, the connection point of the sixth switching unit 107 and the seventh switching unit 108 is connected to the input ground of the load through the ninth switching unit 110 and the tenth switching unit 111 connected in series.
Specifically, a ninth switching unit 110 and a tenth switching unit 111 are provided in series between the connection point of the sixth switching unit 107 and the seventh switching unit 108 and the input zero line of the load, and when the load is connected to the input zero line, the ninth switching unit 110 and the tenth switching unit 111 are closed.
It is to be appreciated that the prior art is not typically connected to the input ground either on the off-grid side or directly from between two switching units connected to the load input hot. In off-grid mode, the two switch units are in a closed state, the output of the inverter is connected to the input ground of the load, and tripping is easily caused by larger leakage current. In this embodiment, the input zero line of the load is controlled by using an independent switch unit to be connected to the input ground line, so as to avoid the situation of larger leakage current of the inverter.
By this embodiment, the use safety is improved and the trip risk is reduced by connecting the ninth switching unit 110 and the tenth switching unit 111 in series to the input ground of the load.
The following describes the specific case when the off-grid switching circuit is applied to a single-phase energy storage inverter and a three-phase energy storage inverter.
In some of these embodiments, the energy storage inverter 101 is a single-phase energy storage inverter or a three-phase energy storage inverter.
Referring to fig. 4, the energy storage inverter 101 is a single-phase energy storage inverter. Each switch unit in the circuit adopts a relay, the energy storage inverter 101 is connected to a first input live wire L1 of the power grid through a relay K1 and a relay K2 which are connected in series, and is connected to a first input neutral wire N1 of the power grid through a relay K3 and a relay K4 which are connected in series; the energy storage inverter 101 is also connected to a second input live wire L2 of the load through a relay K7 and connected to a second input neutral wire N2 of the load through a relay K8; and the connection point of the relay K1 and the relay K2 is connected to the second input live wire L2 through the relay K5; the junction of relay K3 and relay K4 is connected to the second input neutral line through relay K6.
In order to reduce the tripping risk, a connection point of the relay K6 and the relay K7 is arranged and is connected to an input ground line PE of a load through the relay K9 and the relay K10 which are connected in series, so that when only the relay K7 and the relay K8 are closed, the output of the inverter is not connected to the PE, and the leakage current of the inverter is prevented from being excessively large.
Further, the photovoltaic power supply system and the energy storage battery 1142 are respectively connected with the energy storage inverter 101, when the power grid fails, only the relay K7 and the relay K8 are closed, and the photovoltaic power supply system and the energy storage battery 1142 supply power for the load; when the power grid is electrified, the relay K2, the relay K4, the relay K5 and the relay K6 in the circuit are always closed. At this time, if the electric energy output by the energy storage inverter 101 can meet the load demand, the relay K1 and the relay K3 are controlled to be closed, and the redundant electric energy is transmitted to the power grid; if the energy storage inverter 101 outputs less electric energy and can only bear part of the power supply requirement of the load, the electric energy is supplemented to the load by the power grid.
In addition, referring to fig. 5, the energy storage inverter 101 is a three-phase energy storage inverter. Each switch unit in the circuit adopts a relay, and the energy storage inverter 101 is connected to a first input live wire L3, L4 and L5 of the power grid through a relay K11 and a relay K12 which are connected in series, a relay K13 and a relay K14 which are connected in series and a relay K15 and a relay K16 which are connected in series, and is connected to a first input neutral wire N3 of the power grid through a relay K17 and a relay K18 which are connected in series; the energy storage inverter 101 is also connected to second input live wires L6, L7 and L8 of the load through a relay K19, a relay K20 and a relay K21 respectively, and is connected to a second input neutral wire N4 of the load through a relay K22;
and the connection point of the relay K11 and the relay K12, the connection point of the relay K13 and the relay K14 and the connection point of the relay K15 and the relay K16 are respectively connected to the corresponding second input live wire through the relay K23, the relay K24 and the relay K25, and the connection point of the relay K17 and the relay K18 is connected to the second input neutral wire through the relay K26. Meanwhile, in order to reduce the trip risk, a connection point of the relay K22 and the relay K26 is provided, and is connected to the input ground PE of the load through the relay K27 and the relay K28 connected in series.
It should be noted that when the off-grid switching circuit is applied to a three-phase energy storage inverter, the working principle is the same as that of the switching circuit of a single-phase energy storage inverter. In the off-grid mode, only the relay K19, the relay K20, the relay K21 and the relay K22 are closed, and the photovoltaic power supply system and the energy storage battery 1142 supply power for the load; in the grid-connected mode, the relays K12, K14, K16, K18, K23, K24, K25 and K26 in the circuit are always closed. At this time, if the electric energy output by the energy storage inverter 101 can meet the load demand, the relay K11, the relay K13, the relay K15 and the relay K17 are controlled to be closed, and the redundant electric energy is transmitted to the power grid; if the energy storage inverter 101 outputs less electric energy and can only bear part of the power supply requirement of the load 113, the power grid and the photovoltaic power supply device 114 jointly supply power to the load.
In some embodiments, in the grid-connected mode, the second switch unit 103, the fourth switch unit 105, the fifth switch unit 106, and the sixth switch unit 107 are all in a closed state.
Specifically, when the grid is able to supply the load, the circuit switches to grid-tie mode, and the second, fourth, fifth and sixth switching units 103, 105, 106, 107 remain closed all the time. At this time, the power supply mode to the load is adjusted according to the electric energy output by the energy storage inverter 101, if the electric energy output by the energy storage inverter 101 realizes the spontaneous self-use of photovoltaic power generation, the first switch unit 102 and the third switch unit 104 are controlled to be closed, and redundant electric energy can be transmitted to the power grid while meeting the load requirement; if the electric energy output by the energy storage inverter 101 cannot fully bear the power supply requirement of the load, the electric energy is supplemented to the load in real time by the power grid, so that the load is prevented from being powered off.
In some embodiments, in off-grid mode, the first switch unit 102, the second switch unit 103, the third switch unit 104, the fourth switch unit 105, the fifth switch unit 106, and the sixth switch unit 107 are all in an off state;
the seventh switching unit 108 and the eighth switching unit 109 are in a closed state.
Specifically, when the power grid fails, the current circuit is switched to the off-grid mode, and the first switch unit 102, the second switch unit 103, the third switch unit 104, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 are controlled to be opened, and the seventh switch unit 108 and the eighth switch unit 109 are controlled to be closed, that is, the output of the energy storage inverter 101 is switched to supply power to the load, so as to realize continuous power transmission to the load, and prevent the situation of power failure of the load.
The present embodiment is described and illustrated below by way of preferred embodiments.
Fig. 6 is a block diagram of a parallel-to-off-grid switching circuit of an energy storage inverter according to a preferred embodiment of the present application, as shown in fig. 6, the circuit includes: the photovoltaic power generation system 1141, the energy storage battery 1142, the energy storage inverter 101 and a plurality of switch units; both the photovoltaic power generation system 1141 and the energy storage battery 1142 are connected to the energy storage inverter 101.
Wherein, between the energy storage inverter 101 and the power grid 112, the energy storage inverter 101 is connected to a first input live wire of the power grid 112 through a first switch unit 102 and a second switch unit 103 which are connected in series, and is connected to a first input neutral wire of the power grid 112 through a third switch unit 104 and a fourth switch unit 105 which are connected in series. For the off-grid side, the energy storage inverter 101 is connected to the second input hot of the load 113 through the seventh switching unit 108 and to the second input neutral of the load 113 through the eighth switching unit 109.
And the connection point of the first switch unit 102 and the second switch unit 103 is connected to the second input live wire through the fifth switch unit 106; the connection point of the third switching unit 104 and the fourth switching unit 105 is connected to the second input zero line through the sixth switching unit 107. Therefore, in the off-grid mode, the first switch unit 102, the second switch unit 103, the third switch unit 104, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 are controlled to be in an open state, the seventh switch unit 108 and the eighth switch unit 109 are closed, and the photovoltaic power generation system 1141 and the energy storage battery 1142 are switched to supply power to the load 113, so that the uninterruptible power requirement of the load 113 is met.
When the circuit is switched to the grid-connected mode, the second switch unit 103, the fourth switch unit 105, the fifth switch unit 106 and the sixth switch unit 107 are kept closed all the time, and the power supply mode to the load 113 is adjusted according to the electric energy provided by the photovoltaic power generation system 1141 and the energy storage battery 1142. If the electric energy output by the energy storage inverter 101 realizes the spontaneous self-use of photovoltaic power generation, the first switch unit 102 and the third switch unit 104 are further controlled to be closed, and the redundant electric energy can be transmitted to the power grid 112 while the requirement of the load 113 is met; if the photovoltaic power generation system 1141 and the energy storage battery provide less power to the load 113, the power grid 112 supplements the power to the load 113.
In addition, the existing method is usually directly connected to the input ground from between two switch units connected to the input live of the load 113, and when the two switch units are in a closed state, the output of the inverter is connected to the input ground of the load 113, and then a trip risk exists. Based on this, in this embodiment, the connection point of the sixth switching unit 107 and the seventh switching unit 108 is connected to the input ground of the load 113 through the ninth switching unit 110 and the tenth switching unit 111 connected in series, and this arrangement can control the second input neutral ground of the load 113 by the independent switching unit, so as to reduce the risk of larger inverter leakage current.
Through the present embodiment, a small number of switching units are provided between the energy storage inverter 101 and the grid-connected side and the off-grid side to realize the grid-connected and off-grid switching. The connection mode can improve the use safety, reduce the parallel-to-off network switching cost of the energy storage inverter 101 and the probability of circuit faults, and improve the reliability of switching control. In addition, as the power grid 112 is connected to the off-grid side by using an independent switch unit, the off-grid noninductive switching can be realized, the load 113 is prevented from being stopped due to overlong switching time, and the uninterrupted power supply requirement of the load 113 is met.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the utility model, which are described in detail and are not to be construed as limiting the scope of the utility model. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of protection of the present utility model is to be determined by the appended claims.
Claims (10)
1. The utility model provides a parallel off-grid switching circuit of energy storage dc-to-ac converter which characterized in that, the switching circuit includes: an energy storage inverter (101) and a plurality of switching units;
the energy storage inverter (101) is connected to a first input live wire of the power grid (112) through a first switching unit (102) and a second switching unit (103) which are connected in series, and is connected to a first input zero wire of the power grid (112) through a third switching unit (104) and a fourth switching unit (105) which are connected in series;
the energy storage inverter (101) is also connected to a second input live wire of the load (113) through a seventh switching unit (108), and is connected to a second input neutral wire of the load (113) through an eighth switching unit (109);
the connection point of the first switch unit (102) and the second switch unit (103) is connected to the second input live wire through a fifth switch unit (106);
the connection point of the third switching unit (104) and the fourth switching unit (105) is connected to the second input zero line through a sixth switching unit (107).
2. The grid-connected and off-grid switching circuit of an energy storage inverter of claim 1, wherein the switching unit is a relay or an ac contactor.
3. The grid-connected and off-grid switching circuit of an energy storage inverter according to claim 1, further comprising a photovoltaic power supply device (114), the photovoltaic power supply device (114) being connected with the energy storage inverter (101).
4. A grid-connected and off-grid switching circuit of an energy storage inverter according to claim 3, characterized in that the photovoltaic power supply means (114) comprises a photovoltaic power generation system (1141) and an energy storage battery (1142);
the photovoltaic power generation system (1141) and the energy storage battery (1142) are both connected with the energy storage inverter (101).
5. The grid-connected switching circuit of an energy storage inverter according to claim 1, characterized in that the connection point of the sixth switching unit (107) and the seventh switching unit (108) is connected to the input ground of the load (113) via a ninth switching unit (110) and a tenth switching unit (111) connected in series.
6. The grid-connected/off-grid switching circuit of an energy storage inverter according to claim 1, wherein the energy storage inverter (101) is a single-phase energy storage inverter or a three-phase energy storage inverter.
7. The grid-connected/off-grid switching circuit of an energy storage inverter according to claim 1, wherein in grid-connected mode, the second switching unit (103), the fourth switching unit (105), the fifth switching unit (106) and the sixth switching unit (107) are all in a closed state.
8. The grid-connected switching circuit of an energy storage inverter according to claim 1, wherein in grid-connected mode, the first switching unit (102), the second switching unit (103), the third switching unit (104), the fourth switching unit (105), the fifth switching unit (106) and the sixth switching unit (107) are all in an off-state;
the seventh switching unit (108) and the eighth switching unit (109) are in a closed state.
9. An energy storage inverter comprising the off-grid switching circuit of the energy storage inverter of any one of claims 1 to 8.
10. A photovoltaic energy storage system comprising a power grid, a load, and the energy storage inverter of claim 9.
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| CN202322095294.8U CN220711145U (en) | 2023-08-04 | 2023-08-04 | Parallel-to-off-grid switching circuit of energy storage inverter, energy storage inverter and photovoltaic energy storage system |
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| CN202322095294.8U CN220711145U (en) | 2023-08-04 | 2023-08-04 | Parallel-to-off-grid switching circuit of energy storage inverter, energy storage inverter and photovoltaic energy storage system |
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