Charging circuit and energy storage converter system

Abstract

The utility model relates to the technical field of battery energy storage, and discloses a charging circuit and an energy storage converter system, when an energy storage circuit is lack of power, at least one charging branch is connected in series into a loop, the charging branch limits the current of an alternating current power supply and then transmits the current to an energy storage converter, and the energy storage converter converts the current into the alternating current power supply. The energy storage converter converts the input alternating current into the direct current and then charges the energy storage circuit, so that the problems that the converter cannot work after the battery is insufficient in power and the battery needs to be charged manually are solved, the safety is high, field wiring for charging is not needed, and possible accidental injury to personnel in a high-voltage scene is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of battery energy storage, in particular to a power supply replenishment circuit and an energy storage inverter system. Background Art

[0002] When the energy storage battery in the electrochemical energy storage system has not been charged for a long time and the power is severely depleted, the battery is power-deficient and the voltage is low. In a traditional energy storage inverter, the bus capacitor voltage is pre-charged by the energy provided by the battery side. When the battery voltage is lower than the peak value of the grid side voltage, the pre-charging of the bus capacitor voltage is incomplete. At this time, when the grid side switch is closed, the grid side energy flows back. If it is much lower than the limit value, a huge impact current will be generated by uncontrolled rectification, which may seriously cause the inverter and the battery system to fail. Generally, the solution is that the inverter reports a fault and stops running. The maintenance personnel use a mobile power supply replenishment device to connect the wires on-site for power supply replenishment. After the battery voltage is higher than the limit value, the inverter operates to charge the battery.

[0003] In related technologies, the inverter does not support power supply replenishment in the power-deficient state of the battery. The traditional method has high operation and maintenance costs, does not meet the requirements of intelligent application scenarios, and only considers the function implementation, without making a specific analysis of the safety in high-voltage scenarios and cannot meet the safety requirements. Summary of the Utility Model

[0004] In view of this, the utility model provides a power supply replenishment circuit and an energy storage inverter system to solve the problem that the inverter cannot work after the battery is power-deficient and manual power supply replenishment for the battery is required in related technologies.

[0005] In a first aspect, the utility model provides a power supply replenishment circuit applied to an energy storage inverter system. The energy storage inverter system includes an energy storage circuit, a support capacitor, and an energy storage inverter. The energy storage circuit and the support capacitor are both connected in parallel to the DC side of the energy storage inverter. The power supply replenishment circuit includes: at least one power supply replenishment branch. Among them, for the power supply replenishment branch, its first end is connected to one phase of the AC side of the energy storage inverter, and its second end is connected to the corresponding phase of the AC power supply. When the energy storage device is power-deficient, after at least one power supply replenishment branch is connected in series to the AC side of the energy storage inverter to form a closed loop, the power supply replenishment branch limits the current of the AC power supply and then transports it to the energy storage inverter. The energy storage inverter converts the input alternating current into direct current and then charges the energy storage circuit.

[0006] When the energy storage circuit is power-deficient, the utility model solves the problem that the inverter cannot work after the battery is power-deficient and manual power supply replenishment for the battery is required by connecting at least one power supply replenishment branch into the loop. The power supply replenishment branch limits the current of the AC power supply and then transports it to the energy storage inverter. The energy storage inverter converts the input alternating current into direct current and then charges the energy storage circuit. Moreover, it has high safety, does not require on-site wiring for power supply replenishment, and avoids potential accidental injuries to personnel in high-voltage scenarios.

[0007] In an alternative embodiment, the power replenishment branch includes a switching unit and a current limiting unit. The switching unit has its first end connected to one phase of the AC side of the energy storage inverter, and its second end connected to the first end of the current limiting unit. The current limiting unit has its second end connected to the corresponding phase of the AC power supply. When the energy storage device is power-deficient, the switching unit is closed, and the current limiting unit is connected in series to the AC side of the energy storage inverter.

[0008] The power replenishment branch of the present utility model is only composed of a switching unit and a current limiting unit. By controlling the on / off of the switching unit, the connection and disconnection of the power replenishment branch are controlled. The circuit structure is simple and the cost is low.

[0009] In an alternative embodiment, the switching unit includes any one of a relay, a transistor, and a reed switch.

[0010] In an alternative embodiment, the current limiting unit includes at least one current limiting resistor.

[0011] In a second aspect, the present utility model provides an energy storage inverter system, including an energy storage circuit, a support capacitor, an energy storage inverter, a plurality of switching branches, and at least one power replenishment branch according to the first aspect and any of its alternative embodiments. The DC side of the energy storage inverter is respectively connected in parallel with the energy storage circuit and the support capacitor. Each phase of its AC side is connected to the corresponding phase of the AC power supply through a switching branch, and at least one phase of its AC side is connected to the corresponding phase of the AC power supply through a power replenishment branch. When the energy storage circuit is power-deficient, after at least one power replenishment branch is connected in series to the AC side of the energy storage inverter to form a closed loop, the power replenishment branch limits the current of the AC power supply and then delivers it to the energy storage inverter. The energy storage inverter converts the input alternating current into direct current and then charges the energy storage circuit.

[0012] In an alternative embodiment, the switching branch includes a first switch and a second switch. The first switch has its first end connected to one phase of the AC side of the energy storage inverter, and its second end connected to the corresponding phase of the AC power supply through the second switch. When this phase of the AC side of the energy storage inverter is also connected to the corresponding phase of the AC power supply through a power replenishment branch, the second end of the first switch is connected to the first end of the power replenishment branch, and the second end of the power replenishment branch is connected to the corresponding phase of the AC power supply. When the power replenishment branch connected to this phase of the AC side of the energy storage inverter is connected in series to the loop, the first switch of this phase is closed and the second switch is opened.

[0013] In an alternative embodiment, when the energy storage converter is a single-phase converter and only one phase on the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through a power supply replenishment branch, the AC phase connected with the power supply replenishment branch is denoted as the first phase, and the AC phase not connected with the power supply replenishment branch is denoted as the second phase. Then, when the energy storage circuit is short of power, the switch unit of the power supply replenishment branch is closed, the first switch of the switch branch of the first phase is closed, the second switch is opened, and at the same time, the first switch of the switch branch of the second phase is closed, and the second switch is closed.

[0014] In an alternative embodiment, when the energy storage converter is a single-phase converter and each phase on the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through a power supply replenishment branch, the two AC phases are respectively denoted as the first phase and the second phase. Then, when the energy storage circuit is short of power and a power supply replenishment branch needs to be connected in series to the circuit, the switch unit of the power supply replenishment branch of the first phase is closed, the switch unit of the power supply replenishment branch of the second phase is opened, the first switch of the switch branch of the first phase is closed, the second switch is opened, and at the same time, the first switch of the switch branch of the second phase is closed, and the second switch is closed; or, the switch unit of the power supply replenishment branch of the second phase is closed, the switch unit of the power supply replenishment branch of the first phase is opened, the first switch of the switch branch of the second phase is closed, the second switch is opened, and at the same time, the first switch of the switch branch of the first phase is closed, and the second switch is closed; when the energy storage circuit is short of power and two power supply replenishment branches need to be connected in series to the circuit, the switch units of the power supply replenishment branches of the first phase and the second phase are both closed, the first switches of the switch branches of the first phase and the second phase are closed, and the second switches are opened.

[0015] In an alternative embodiment, when the energy storage converter is a three-phase converter and only one phase on the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through a power supply replenishment branch, the AC phase connected with the power supply replenishment branch is denoted as the first phase, and the AC phases not connected with the power supply replenishment branch are denoted as the second phase and the third phase. Then, when the energy storage circuit is short of power, the switch unit of the power supply replenishment branch is closed, the first switch of the switch branch of the first phase is closed, the second switch is opened, and at the same time, the first switch of the switch branch of the second phase is closed, and the second switch is closed, the first switch of the switch branch of the third phase is opened, and the second switch is opened; or, when the energy storage circuit is short of power, the switch unit of the power supply replenishment branch is closed, the first switch of the switch branch of the first phase is closed, the second switch is opened, and at the same time, the first switch of the switch branch of the third phase is closed, and the second switch is closed, the first switch of the switch branch of the second phase is opened, and the second switch is opened.

[0016] In an alternative embodiment, when the energy storage converter is a three-phase converter, and when two phases on the AC side of the energy storage converter are connected to the corresponding phases of the AC power supply through a charging branch, the AC phases connected with the charging branch are denoted as the first phase and the second phase, and the AC phase not connected with the charging branch is denoted as the third phase. Then, when the energy storage circuit is short of power and only one charging branch needs to be connected in series to the circuit, the switching unit of the charging branch of the first phase is closed, and the first switch of the switching branch of the first phase is closed and the second switch is opened. The first switch of the switching branch of any one of the second phase or the third phase is closed and the second switch is closed, and the first switch of the switching branch of the other one of the second phase or the third phase is opened and the second switch is opened; or, when the energy storage circuit is short of power and only one charging branch needs to be connected in series to the circuit, the switching unit of the charging branch of the second phase is closed, and the first switch of the switching branch of the second phase is closed and the second switch is opened. The first switch of the switching branch of any one of the first phase or the third phase is closed and the second switch is closed, and the first switch of the switching branch of the other one of the first phase or the third phase is opened and the second switch is opened; when the energy storage circuit is short of power and two charging branches need to be connected in series to the circuit, the switching unit of the charging branch of the first phase is closed, the switching unit of the charging branch of the second phase is closed, and the first switches of the first phase and the second phase are closed and the second switches are opened.

[0017] In an alternative embodiment, when the energy storage converter is a three-phase converter, and each phase on the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through a charging branch, then when the energy storage circuit is short of power and only one charging branch needs to be connected in series to the circuit, the switching unit of the charging branch of any one phase is closed, and the first switch of the switching branch of this phase is closed and the second switch is opened. At the same time, the first switch of the switching branch of any one of the remaining two phases is closed and the second switch is closed, and the first switch of the switching branch of the other one of the remaining two phases is opened and the second switch is opened; when the energy storage circuit is short of power and two charging branches need to be connected in series to the circuit, the switching units of the charging branches of any two phases are closed, and the first switches of the switching branches of these two phases are closed and the second switches are opened; when the energy storage circuit is short of power and three charging branches need to be connected in series to the circuit, the switching units of the charging branches of each phase are closed, and the first switches of the switching branches of each phase are closed and the second switches are opened.

[0018] In an alternative embodiment, the first switch and the switching unit it is connected to are redundant. Then, when the first switch fails, the charging branch is cut out by disconnecting the switching unit, or when the switching unit fails, the charging branch is cut out by disconnecting the first switch. Description of the Drawings

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 is a schematic structural diagram of a power replenishment circuit according to an embodiment of the present invention;

[0021] Figure 2 is a schematic structural diagram of another power replenishment circuit according to an embodiment of the present invention;

[0022] Figure 3 is a schematic structural diagram of an energy storage inverter system according to an embodiment of the present invention;

[0023] Figures 4 to 8 are respectively schematic structural diagrams of an energy storage inverter system according to an embodiment of the present invention. Specific Embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] In this embodiment, a power replenishment circuit is provided, which is applied to an energy storage inverter system. As Figure 1 shown, the energy storage inverter system includes an energy storage circuit 1, a support capacitor 2, and an energy storage inverter 3. The energy storage circuit 1 and the support capacitor 2 are both connected in parallel to the DC side of the energy storage inverter 3. The power replenishment circuit includes: at least one power replenishment branch 4. It should be noted that Figure 1 in this example, the energy storage inverter 3 is a three-phase inverter, and each phase is connected to a power replenishment circuit. However, if the power that the power replenishment circuit can consume is large enough, that is, sufficient to limit the current of the AC power supply to a certain threshold, the energy storage inverter 3 can be connected to only one or two power replenishment circuits, and no limitation is made here.

[0026] As Figure 1 shown, for the power replenishment branch 4, its first end is connected to one phase of the AC side of the energy storage inverter 3, and its second end is connected to the corresponding phase of the AC power supply; Figure 1Among them, the first end of the switching branch is connected to one phase of the energy storage converter 3, the second end of the switching branch is connected to the corresponding phase of the AC power supply, the third end of the switching branch is connected to the first end of the charging branch 4, and the second end of the charging branch 4 is connected to the corresponding phase of the AC power supply.

[0027] Specifically, when the energy storage device is short of electricity, after at least one charging branch 4 is connected in series to the AC side of the energy storage converter 3 to form a closed loop, the charging branch 4 limits the current of the AC power supply and then delivers it to the energy storage converter 3. The energy storage converter 3 converts the input alternating current into direct current and then charges the energy storage circuit 1.

[0028] Specifically, Figure 1 Among them, when the energy storage circuit 1 is not short of electricity, when the switching branch is in the first switching state, that is, when the switching branch is completely conducting, and the charging branch 4 is in the off state, the AC side of the energy storage converter 3 is directly connected to the AC power supply; when the energy storage circuit 1 is short of electricity, in order to avoid directly using the AC power supply to charge the energy storage circuit 1, which may cause a huge inrush current in the energy storage converter 3 and even lead to the failure of the converter and the battery system, at least one charging branch 4 needs to be connected in series to the loop. The charging branch 4 consumes part of the alternating current, that is, the charging branch 4 limits the alternating current and then delivers it to the energy storage converter 3. The energy storage converter 3 converts the alternating current into direct current to supply power to the energy storage circuit 1.

[0029] Specifically, in order to achieve safety redundancy protection, the switching branch is at least divided into two branches. The first end of the first branch is connected to one phase of the AC side of the energy storage converter 3, the second end of the first branch is connected to the first end of the second branch and the first end of the charging branch 4, and the second end of the second branch is connected to the second end of the charging branch 4 and the corresponding phase of the AC power supply. Then, when the energy storage circuit 1 is short of electricity, the first branch needs to be turned on, the second branch needs to be turned off, and the charging branch 4 needs to be turned on, so that the alternating current is delivered to the energy storage converter 3 through the charging branch 4 and the first branch in sequence. At the same time, in this embodiment, the first end of the charging branch 4 is not directly connected to the energy storage converter 3 so that when the first branch fails, the fault can be removed by disconnecting the charging branch 4, or when the charging branch 4 fails, the fault can be removed by disconnecting the first branch.

[0030] Specifically, when the energy storage circuit 1 is short of electricity, the number of charging branches 4 to be connected in series is determined according to the resistance value of the charging branch 4 and the current value of the AC power supply. However, when selecting the charging branch 4 to be connected in series, each loop on the AC side of the energy storage converter 3 needs to have a charging branch 4 for current limitation. Exemplarily, taking Figure 1 as an example for illustration:

[0031] (1) When only the charging branch 4 of one phase needs to be connected in series, the first branch and the charging circuit of this phase are turned on at this time, while only one phase of the switching branches of the remaining two phases can be turned on. If the switching branches of the remaining two phases are both turned on, then the charging branch 4 is not connected in series in the loop formed by the remaining two phases, so the alternating current of the AC power supply is directly transmitted to the energy storage converter 3 without being suppressed, and the energy storage converter 3 may still generate a huge impact current.

[0032] (2) When the charging branches 4 of two phases need to be connected in series, the first branches and the charging circuits of these two phases are turned on at this time, and the switching branch of the remaining one phase can be either turned on or off.

[0033] In some alternative embodiments, as Figure 2 shown, the charging branch 4 includes: a switching unit 41 and a current limiting unit 42.

[0034] Figure 2 Among them, for the switching unit 41, its first end is connected to one phase of the AC side of the energy storage converter 3, and its second end is connected to the first end of the current limiting unit 42; for the current limiting unit 42, its second end is connected to the corresponding phase of the AC power supply; when the energy storage device is short of power, the switching unit 41 is closed, and the current limiting unit 42 is connected in series to the AC side of the energy storage converter 3.

[0035] Optionally, the switching unit 41 includes any one of a relay, a transistor, and a reed switch, but only as an example here and not limited thereto.

[0036] Optionally, the current limiting unit 42 includes at least one current limiting resistor. When multiple current limiting resistors are included, all the current limiting resistors are connected in series and / or in parallel.

[0037] This embodiment provides an energy storage conversion system, as Figure 1 shown, including: an energy storage circuit 1, a support capacitor 2, an energy storage converter 3, multiple switching branches 5, and the charging branch 4 of the above embodiment and any of its alternative embodiments. Among them, Figure 1 taking the energy storage converter 3 as a three-phase converter and each phase being connected to a charging circuit as an example, but if the power that the charging circuit can consume is large enough, that is, sufficient to limit the current of the AC power supply to a certain threshold, the energy storage converter 3 can be connected to only one or two charging circuits, which is not limited here.

[0038] As Figure 1 shown, for the energy storage converter 3, its DC side is respectively connected in parallel with the energy storage circuit 1 and the support capacitor 2, each phase of its AC side is connected to the corresponding phase of the AC power supply through a switching branch 5, and at least one phase of its AC side is connected to the corresponding phase of the AC power supply through a charging branch 4.

[0039] Optionally, taking a three-phase converter as an example, and each phase of the three-phase converter is connected to a charging branch 4, as Figure 3 shown, the switching branch 5 includes: a first switch 51 and a second switch 52. Among them, for the first switch 51, its first end is connected to one phase of the AC side of the energy storage converter 3, and its second end is connected to the corresponding phase of the AC power supply through the second switch 52; when this phase of the AC side of the energy storage converter 3 is also connected to the corresponding phase of the AC power supply through the charging branch 4, the second end of the first switch 51 is connected to the first end of the charging branch 4, and the second end of the charging branch 4 is connected to the corresponding phase of the AC power supply; when the charging branch 4 connected to this phase of the AC side of the energy storage converter 3 is connected in series into the loop, the first switch 51 of this phase is closed and the second switch 52 is opened.

[0040] Specifically, in order to achieve safety redundancy protection, the first switch 51 and the switch unit 41 it is connected to are redundant to each other. Then, when the first switch 51 fails, the charging branch 4 is cut out by disconnecting the switch unit 41, or when the switch unit 41 fails, the charging branch 4 is cut out by disconnecting the first switch 51.

[0041] When the energy storage circuit 1 is short of power, after at least one charging branch 4 is connected in series to the AC side of the energy storage converter 3 to form a closed loop, the charging branch 4 limits the current of the AC power supply and then transports it to the energy storage converter 3. The energy storage converter 3 converts the input alternating current into direct current and then charges the energy storage circuit 1. For single-phase converters and three-phase converters, and the number of connected charging branches 4 is a variable. The following is an explanation of the on-off control of each switching branch 5 when the energy storage circuit 1 is short of power:

[0042] (1) When the energy storage converter 3 is a single-phase converter, and only one phase of the AC side of the energy storage converter 3 is connected to the corresponding phase of the AC power supply through a charging branch 4, the AC phase connected to the charging branch 4 is denoted as the first phase, and the AC phase not connected to the charging branch 4 is denoted as the second phase. Then:

[0043] When the energy storage circuit 1 is short of power, close the switch unit 41 of the charging branch 4, close the first switch 51 and open the second switch 52 of the switching branch 5 of the first phase, and at the same time close the first switch 51 and the second switch 52 of the switching branch 5 of the second phase.

[0044] Specifically, referring to Figure 4 , in the figure, S1 and S2 are the first switch 51 and the second switch 52 of the first phase respectively, S4 and S5 are the first switch 51 and the second switch 52 of the second phase respectively, and S3 and R1 are the switch unit 41 and the current limiting unit 42 respectively. Then, when the energy storage circuit 1 is short of power, close S1, S3, S4, and S5, and at the same time open S2, so that R1 is connected in series into the loop.

[0045] (2) When the energy storage converter 3 is a single-phase converter, and each phase of the AC side of the energy storage converter 3 is connected to the corresponding phase of the AC power supply through a power supply replenishment branch 4, and the two AC phases are respectively denoted as the first phase and the second phase, then:

[0046] ① When the energy storage circuit 1 is short of power and it is necessary to connect a power supply replenishment branch 4 into the circuit, close the switch unit 41 of the power supply replenishment branch 4 of the first phase, open the switch unit 41 of the power supply replenishment branch 4 of the second phase, close the first switch 51 of the switch branch 5 of the first phase, open the second switch 52, and at the same time, close the first switch 51 of the switch branch 5 of the second phase and close the second switch 52; or, close the switch unit 41 of the power supply replenishment branch 4 of the second phase, open the switch unit 41 of the power supply replenishment branch 4 of the first phase, close the first switch 51 of the switch branch 5 of the second phase, open the second switch 52, and at the same time, close the first switch 51 of the switch branch 5 of the first phase and close the second switch 52.

[0047] Specifically, referring to Figure 5 , in the figure, S1 and S2 are respectively the first switch 51 and the second switch 52 of the first phase, S4 and S5 are respectively the first switch 51 and the second switch 52 of the second phase, S3 and R1 are respectively the switch unit 41 and the current limiting unit 42 of the first phase, and S6 and R2 are respectively the switch unit 41 and the current limiting unit 42 of the first phase.

[0048] Figure 5 In, when the energy storage circuit 1 is short of power and the power supply replenishment branch 4 of the first phase is connected into the circuit, close S1, S2, S4, and S6, and at the same time, open S3 and S5, so that R2 is connected into the circuit. Or, when the energy storage circuit 1 is short of power and the power supply replenishment branch 4 of the first phase is connected into the circuit, close S1, S3, S4, and S5, and at the same time, open S2 and S6, so that R1 is connected into the circuit.

[0049] ② When the energy storage circuit 1 is short of power and it is necessary to connect two power supply replenishment branches 4 into the circuit, close the switch units 41 of the power supply replenishment branches 4 of the first phase and the second phase, close the first switches 51 of the switch branches 5 of the first phase and the second phase, and open the second switches 52.

[0050] Specifically, referring to Figure 5 , when the energy storage circuit 1 is short of power and it is necessary to connect two power supply replenishment branches 4 into the circuit, close S1, S3, S4, and S6, and at the same time, open S2 and S5, so that R1 and R2 are connected into the circuit.

[0051] (3) When the energy storage converter 3 is a three-phase converter, and only one phase of the AC side of the energy storage converter 3 is connected to the corresponding phase of the AC power supply through a power supply replenishment branch 4, the AC phase connected with the power supply replenishment branch 4 is denoted as the first phase, and the AC phases not connected with the power supply replenishment branch 4 are denoted as the second phase and the third phase, then:

[0052] ① When the energy storage circuit 1 is short of power, close the switch unit 41 of the power supply replenishment branch 4, and close the first switch 51 and open the second switch 52 of the switch branch 5 of the first phase. At the same time, close the first switch 51 and the second switch 52 of the switch branch 5 of the second phase, and open the first switch 51 and open the second switch 52 of the switch branch 5 of the third phase.

[0053] ② Or, when the energy storage circuit 1 is short of power, close the switch unit 41 of the power supply replenishment branch 4, and close the first switch 51 and open the second switch 52 of the switch branch 5 of the first phase. At the same time, close the first switch 51 and the second switch 52 of the switch branch 5 of the third phase, and open the first switch 51 and open the second switch 52 of the switch branch 5 of the second phase.

[0054] Specifically, referring to Figure 6 , in the figure, S1 and S2 are respectively the first switch 51 and the second switch 52 of the first phase, S4 and S5 are respectively the first switch 51 and the second switch 52 of the second phase, S6 and S7 are respectively the first switch 51 and the second switch 52 of the third phase, and S3 and R1 are respectively the switch unit 41 and the current limiting unit 42 of the first phase.

[0055] Figure 6 In [reference], when the energy storage circuit 1 is short of power, close S1, S3, S4, and S5, open S2, S6, and S7, and R1 is connected in series to the circuit; or when the energy storage circuit 1 is short of power, close S1, S3, S6, and S7, open S2, S4, and S5, and R1 is connected in series to the circuit.

[0056] It should be noted that when the energy storage circuit 1 is short of power, the switch branches 5 of the second phase and the third phase cannot be closed simultaneously, that is, S4, S5, S6, and S7 cannot be closed simultaneously. Only S4 and S5 can be closed, and S6 and S7 can be opened, or S6 and S7 can be closed, and S4 and S5 can be opened. If the switch branches 5 of the second phase and the third phase are closed simultaneously, there is no current limiting unit 42 connected in series in the loop formed by S4, S5, S6, and S7, so that the current of the AC power supply is directly transmitted to the energy storage converter 3, which may cause a huge impact current in the energy storage converter 3.

[0057] (4) When the energy storage converter 3 is a three-phase converter, when the energy storage converter 3 is a three-phase converter, and two phases on the AC side of the energy storage converter 3 are connected to the corresponding phases of the AC power supply through a power supply replenishment branch 4, the AC phases connected to the power supply replenishment branch 4 are denoted as the first phase and the second phase, and the AC phase not connected to the power supply replenishment branch 4 is denoted as the third phase. Then

[0058] ① When the energy storage circuit 1 is short of power and only one charging branch 4 needs to be connected in series to the circuit, close the switch unit 41 of the charging branch 4 of the first phase, and close the first switch 51 and open the second switch 52 of the switch branch 5 of the first phase. Close the first switch 51 and close the second switch 52 of the switch branch 5 of any one of the second phase or the third phase, and open the first switch 51 and open the second switch 52 of the switch branch 5 of the other phase of the second phase or the third phase.

[0059] Specifically, referring to Figure 7 , in the figure, S1 and S2 are respectively the first switch 51 and the second switch 52 of the first phase, S4 and S5 are respectively the first switch 51 and the second switch 52 of the second phase, S7 and S8 are respectively the first switch 51 and the second switch 52 of the third phase, S3 and R1 are respectively the switch unit 41 and the current limiting unit 42 of the first phase, and S6 and R2 are respectively the switch unit 41 and the current limiting unit 42 of the second phase.

[0060] Figure 7 In

[0061] , when the energy storage circuit 1 is short of power and only one charging branch 4 needs to be connected in series to the circuit, if the charging branch 4 of the first phase is connected in series to the circuit, close S1, S3, S4, S5, open S2, S6, S7, S8, and R1 is connected in series to the circuit; or, close S1, S3, S7, S8, open S2, S4, S5, S6, and R1 is connected in series to the circuit.

[0062] It should be noted that when the energy storage circuit 1 is short of power, if the charging branch 4 of the first phase is connected in series to the circuit, the switch branches 5 of the second phase and the third phase cannot be closed at the same time, that is, S4, S5, S7, S8 cannot be closed at the same time. Only S4 and S5 can be closed, and S7 and S8 can be opened, or S7 and S8 can be closed, and S4 and S5 can be opened.

[0062] ② Or, when the energy storage circuit 1 is short of power and only one charging branch 4 needs to be connected in series to the circuit, close the switch unit 41 of the charging branch 4 of the second phase, and close the first switch 51 and open the second switch 52 of the switch branch 5 of the second phase. Close the first switch 51 and close the second switch 52 of the switch branch 5 of any one of the first phase or the third phase, and open the first switch 51 and open the second switch 52 of the switch branch 5 of the other phase of the first phase or the third phase.

[0063] Figure 7 In

[0064] It should be noted that when the energy storage circuit 1 is short of power, if the second-phase power supply replenishment branch 4 is connected in series to the circuit, the switch branches 5 of the first phase and the third phase cannot be closed simultaneously, that is, S1, S2, S7, and S8 cannot be closed simultaneously. Only S1 and S2 can be closed, and S7 and S8 are disconnected, or S7 and S8 are closed, and S1 and S2 are disconnected.

[0065] ③ When the energy storage circuit 1 is short of power and it is necessary to connect both power supply replenishment branches 4 in series to the circuit, close the switch unit 41 of the power supply replenishment branch 4 of the first phase, close the switch unit 41 of the power supply replenishment branch 4 of the second phase, and close the first switch 51 and open the second switch 52 of the first phase and the second phase.

[0066] Figure 7 In, when the energy storage circuit 1 is short of power and it is necessary to connect both power supply replenishment branches 4 in series to the circuit, close S1, S3, S4, and S6, open S2 and S5, and S7 and S8 can be either closed or open.

[0067] (5) When the energy storage converter 3 is a three-phase converter and each phase of the AC side of the energy storage converter 3 is connected to the corresponding phase of the AC power supply through a power supply replenishment branch 4, then:

[0068] ① When the energy storage circuit 1 is short of power and only one power supply replenishment branch 4 needs to be connected in series to the circuit, close the switch unit 41 of the power supply replenishment branch 4 of any one phase, close the first switch 51 and open the second switch 52 of the switch branch 5 of this phase, and at the same time close the first switch 51 and open the second switch 52 of the switch branch 5 of any one of the remaining two phases, and open the first switch 51 and close the second switch 52 of the switch branch 5 of the other phase of the remaining two phases.

[0069] Specifically, referring to Figure 8 , in the figure, S1 and S2 are respectively the first switch 51 and the second switch 52 of the first phase, S4 and S5 are respectively the first switch 51 and the second switch 52 of the second phase, S7 and S8 are respectively the first switch 51 and the second switch 52 of the third phase, S3 and R1 are respectively the switch unit 41 and the current limiting unit 42 of the first phase, S6 and R2 are respectively the switch unit 41 and the current limiting unit 42 of the second phase, and S9 and R3 are respectively the switch unit 41 and the current limiting unit 42 of the second phase.

[0070] Figure 8 In, when the energy storage circuit 1 is short of power and only one power supply replenishment branch 4 needs to be connected in series to the circuit, when connecting the power supply replenishment branch 4 of the first phase, close S1, S3, S4, and S5, open S2, S6, S7, S8, and S9, and R1 is connected in series to the circuit; or, close S1, S3, S7, and S8, open S2, S4, S5, S6, and S9, and R1 is connected in series to the circuit.

[0071] It should be noted that when the energy storage circuit 1 is power-deficient, if the first-phase power supply replenishment branch 4 is connected in series to the circuit, the switch branches 5 of the first phase and the third phase cannot be closed simultaneously, that is, S4, S5, S7, and S8 cannot be closed simultaneously. Only S4 and S5 can be closed while S7 and S8 are opened, or S7 and S8 can be closed while S4 and S5 are opened.

[0072] Figure 8 In [circuit description], when the energy storage circuit 1 is power-deficient and only one power supply replenishment branch 4 needs to be connected in series to the circuit, when the second-phase power supply replenishment branch 4 is connected in series, close S1, S2, S4, and S6, open S3, S5, S7, S8, and S9, and R2 is connected in series to the circuit; or, close S4, S6, S7, and S8, open S1, S2, S3, S5, and S9, and R2 is connected in series to the circuit.

[0073] It should be noted that when the energy storage circuit 1 is power-deficient, if the second-phase power supply replenishment branch 4 is connected in series to the circuit, the switch branches 5 of the first phase and the third phase cannot be closed simultaneously, that is, S1, S2, S7, and S8 cannot be closed simultaneously. Only S1 and S2 can be closed while S7 and S8 are opened, or S7 and S8 can be closed while S1 and S2 are opened.

[0074] Figure 8 In [circuit description], when the energy storage circuit 1 is power-deficient and only one power supply replenishment branch 4 needs to be connected in series to the circuit, when the third-phase power supply replenishment branch 4 is connected in series, close S1, S2, S7, and S9, open S3, S4, S5, S6, and S8, and R3 is connected in series to the circuit; or, close S4, S5, S7, and S9, open S1, S2, S3, S6, and S8, and R3 is connected in series to the circuit.

[0075] It should be noted that when the energy storage circuit 1 is power-deficient, if the second-phase power supply replenishment branch 4 is connected in series to the circuit, the switch branches 5 of the first phase and the third phase cannot be closed simultaneously, that is, S1, S2, S4, and S5 cannot be closed simultaneously. Only S1 and S2 can be closed while S4 and S5 are opened, or S4 and S5 can be closed while S1 and S2 are opened.

[0076] ② When the energy storage circuit 1 is power-deficient and two power supply replenishment branches 4 need to be connected in series to the circuit, close the switch units 41 of the power supply replenishment branches 4 of any two phases, and close the first switches 51 and open the second switches 52 of the switch branches 5 of these two phases.

[0077] Figure 8 In [circuit description], when the energy storage circuit 1 is power-deficient and two power supply replenishment branches 4 need to be connected in series to the circuit, when the first-phase and second-phase power supply replenishment branches 4 are connected in series, close S1, S3, S4, and S6, open S2, S5, and S9, and S7 and S8 can be either closed or opened, and R1 and R2 are connected in series to the circuit.

[0078] Figure 8In [the circuit], when the energy storage circuit 1 is short of power and two power supply supplement branches 4 need to be connected in series to the circuit, when the first-phase and third-phase power supply supplement branches 4 are connected in series, close S1, S3, S7, and S9, open S2, S6, and S7, S4 and S5 can be either closed or open, and R1 and R3 are connected in series to the circuit.

[0079] Figure 8 In [the circuit], when the energy storage circuit 1 is short of power and two power supply supplement branches 4 need to be connected in series to the circuit, when the second-phase and third-phase power supply supplement branches 4 are connected in series, close S4, S6, S7, and S9, open S3, S5, and S8, S1 and S2 can be either closed or open, and R2 and R3 are connected in series to the circuit.

[0080] ③ When the energy storage circuit 1 is short of power and three power supply supplement branches 4 need to be connected in series to the circuit, close the switch unit 41 of the power supply supplement branch 4 of each phase, and close the first switch 51 and open the second switch 52 of the switch branch 5 of each phase.

[0081] Figure 8 In [the circuit], when the energy storage circuit 1 is short of power and three power supply supplement branches 4 need to be connected in series to the circuit, close S1, S3, S4, S6, S7, and S9, open S2, S5, and S8, and R1, R2, and R3 are connected in series to the circuit.

[0082] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A power compensation circuit, characterized in that: Applied to an energy storage conversion system, the energy storage conversion system includes an energy storage circuit, a support capacitor and an energy storage converter, the energy storage circuit and the support capacitor are connected in parallel with the DC side of the energy storage converter, and the power compensation circuit includes: at least one power compensation branch, wherein: A power supply branch, a first end of which is connected to a phase of the AC side of the energy storage converter, and a second end of which is connected to a corresponding phase of the AC power supply; When the energy storage device is out of power, at least one of the power compensation branches is connected in series to the AC side of the energy storage inverter to form a closed loop. The power compensation branch limits the current of the AC power supply and transmits it to the energy storage inverter. The energy storage inverter converts the input AC power into DC power to charge the energy storage circuit.

2. The power compensation circuit according to claim 1, characterized in that: The power supplement branch includes: a switch unit and a current limiting unit, wherein: A switch unit, a first end of which is connected to a phase on the AC side of the energy storage converter, and a second end of which is connected to the first end of the current limiting unit; A current limiting unit, a second end of which is connected to the AC power source correspondingly; When the energy storage device is out of power, the switch unit is closed, and the current limiting unit is connected in series to the AC side of the energy storage converter.

3. The power compensation circuit according to claim 2, characterized in that: The switch unit includes: any one of a relay, a transistor, and a reed switch.

4. The power compensation circuit according to claim 3, characterized in that: The current limiting unit includes: at least one current limiting resistor.

5. An energy storage conversion system, characterized in that: include: An energy storage circuit, a supporting capacitor, an energy storage converter, a plurality of switch branches and at least one power supply branch as claimed in any one of claims 2 to 4, wherein: An energy storage converter, wherein the DC side of the converter is connected in parallel with the energy storage circuit and the supporting capacitor respectively, each phase of the AC side of the converter is connected to a corresponding phase of the AC power supply through one of the switch branches, and at least one phase of the AC side of the converter is connected to a corresponding phase of the AC power supply through one of the power compensation branches; When the energy storage circuit is depleted of power, at least one of the power compensation branches is connected in series to the AC side of the energy storage inverter to form a closed loop. The power compensation branch limits the current of the AC power supply and then transmits it to the energy storage inverter. The energy storage inverter converts the input AC power into DC power to charge the energy storage circuit.

6. The energy storage and conversion system according to claim 5, characterized in that: The switch branch includes: a first switch and a second switch, wherein: A first switch, a first end of which is connected to a phase of the AC side of the energy storage converter, and a second end of which is connected to a corresponding phase of the AC power supply through the second switch; When the phase on the AC side of the energy storage converter is also connected to the corresponding phase of the AC power supply through the power compensation branch, the second end of the first switch is connected to the first end of the power compensation branch, and the second end of the power compensation branch is connected to the corresponding phase of the AC power supply; When the power supplement branch connected to the phase on the AC side of the energy storage converter is connected in series with the loop, the first switch of the phase is closed and the second switch is opened.

7. The energy storage and conversion system according to claim 6, characterized in that: When the energy storage converter is a single-phase converter, and only one phase of the AC side of the energy storage converter is connected to the corresponding phase of the AC power source through one of the power supplement branches, the AC phase connected to the power supplement branch is recorded as the first phase, and the AC phase not connected to the power supplement branch is recorded as the second phase. When the energy storage circuit is depleted, the switch unit of the power compensation branch is closed, and the first switch of the first phase switch branch is closed and the second switch is opened, and the first switch of the second phase switch branch is closed and the second switch is closed.

8. The energy storage and conversion system according to claim 6, characterized in that: When the energy storage converter is a single-phase converter, and each phase of the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through one of the power supply branches, the two AC phases are respectively recorded as the first phase and the second phase. When the energy storage circuit is depleted and a supplementary power branch needs to be connected in series to the loop, the switch unit of the supplementary power branch of the first phase is closed, and the switch unit of the supplementary power branch of the second phase is opened, the first switch of the switch branch of the first phase is closed, and the second switch is opened, and the first switch of the switch branch of the second phase is closed, and the second switch is closed; Alternatively, the switch unit of the second phase power supplement branch is closed, the switch unit of the first phase power supplement branch is opened, the first switch of the second phase switch branch is closed, the second switch is opened, and the first switch of the first phase switch branch is closed, the second switch is closed; When the energy storage circuit is depleted and two power supplement branches need to be connected in series into the loop, the switch units of the first and second phase power supplement branches are closed, and the first switches of the first and second phase switch branches are closed and the second switches are opened.

9. The energy storage and conversion system according to claim 6, characterized in that: When the energy storage converter is a three-phase converter, and only one phase of the AC side of the energy storage converter is connected to the corresponding phase of the AC power source through one of the power supplement branches, the AC phase connected to the power supplement branch is recorded as the first phase, and the AC phase not connected to the power supplement branch is recorded as the second phase and the third phase. When the energy storage circuit is depleted, the switch unit of the power supplement branch is closed, and the first switch of the switch branch of the first phase is closed and the second switch is opened, and at the same time, the first switch of the switch branch of the second phase is closed and the second switch is closed, and the first switch of the switch branch of the third phase is opened and the second switch is opened; Alternatively, when the energy storage circuit is depleted of power, the switch unit of the power compensation branch is closed, and the first switch of the first phase switch branch is closed and the second switch is opened, and at the same time, the first switch of the third phase switch branch is closed and the second switch is closed, and the first switch of the second phase switch branch is opened and the second switch is opened.

10. The energy storage and conversion system according to claim 6, characterized in that: When the energy storage converter is a three-phase converter, and two phases of the AC side of the energy storage converter are connected to the corresponding phases of the AC power supply through one of the power supply compensation branches, the AC phases connected to the power supply compensation branch are recorded as the first phase and the second phase, and the AC phase not connected to the power supply compensation branch is recorded as the third phase. When the energy storage circuit is depleted and only one power supplement branch needs to be connected in series to the loop, the switch unit of the power supplement branch of the first phase is closed, and the first switch of the switch branch of the first phase is closed and the second switch is opened, the first switch of the switch branch of any one of the second phase or the third phase is closed and the second switch is closed, and the first switch of the switch branch of the other phase of the second phase or the third phase is opened and the second switch is opened; Alternatively, when the energy storage circuit is depleted and only one power supplement branch needs to be connected in series to the loop, the switch unit of the power supplement branch of the second phase is closed, and the first switch of the switch branch of the second phase is closed and the second switch is opened, the first switch of the switch branch of any one of the first phase or the third phase is closed and the second switch is closed, and the first switch of the switch branch of the other phase of the first phase or the third phase is opened and the second switch is opened; When the energy storage circuit is depleted and both power supplement branches need to be connected in series to the loop, the switch unit of the first phase power supplement branch is closed, the switch unit of the second phase power supplement branch is closed, and the first switches of the first phase and the second phase are closed, and the second switches are opened.

11. The energy storage and current conversion system according to claim 6, characterized in that: When the energy storage converter is a three-phase converter, and each phase of the AC side of the energy storage converter is connected to the corresponding phase of the AC power supply through one of the power supply branches, then When the energy storage circuit is depleted and only one supplementary power branch needs to be connected in series to the loop, the switch unit of the supplementary power branch of any phase is closed, and the first switch of the switch branch of the phase is closed and the second switch is opened, and at the same time, the first switch of the switch branch of any phase of the remaining two phases is closed and the second switch is closed, and the first switch of the switch branch of the other phase of the remaining two phases is opened and the second switch is opened; When the energy storage circuit is depleted and two power supply branches need to be connected in series to the loop, the switch units of any two-phase power supply branches are closed, and the first switches of the switch branches of the two phases are closed and the second switches are opened; When the energy storage circuit is depleted and three power supplement branches need to be connected in series to the loop, the switch unit of each phase of the power supplement branch is closed, and the first switch of each phase of the switch branch is closed and the second switch is opened.

12. The energy storage and current conversion system according to any one of claims 6 to 11, characterized in that: The first switch and the switch unit connected thereto are redundant with each other. When the first switch fails, the power supplement branch is cut off by disconnecting the switch unit; or when the switch unit fails, the power supplement branch is cut off by disconnecting the first switch.

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