Charging circuit of energy storage system

Abstract

The utility model relates to the technical field of energy storage, in particular to a charging circuit of an energy storage system, which comprises a main charging circuit and a charging circuit, the alternating current sides of the main charging circuit and the charging circuit are respectively connected with an alternating current power grid, and the direct current sides of the main charging circuit and the charging circuit are respectively connected with a battery cell of the energy storage system; the charging circuit is used for pre-charging an energy storage system power-deficient battery by adopting low voltage and small current; the charging circuit is a single-phase current conversion circuit; the alternating current sides of a main charging circuit and a charging circuit are respectively connected with an alternating current power grid, and the direct current sides of the main charging circuit and the charging circuit are respectively connected with an energy storage system battery cell; alternating current of a main charging circuit or an alternating current power grid is converted into direct current, low-voltage small-current charging is provided for pre-charging of a battery pack of the energy storage system, the charging rheological circuit or the alternating current power grid shares a charging circuit, the whole energy storage system does not need to be additionally provided with a charging device, and the cost of the whole system is saved.

Description

Technical Field

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

[0002] With the vigorous development of new energy and energy storage industries, the battery packs of energy storage power stations are often charged and discharged during operation. When the battery packs of energy storage power stations are deeply discharged or under power for a long time, the battery cell voltage will drop to the minimum. If the existing high-voltage energy storage system is used, the battery will be damaged due to the excessive charging voltage, affecting its capacity and life.

[0003] Therefore, it is necessary to design an energy storage system power replenishment circuit to improve the above problems and provide low voltage and small current to pre-charge the depleted battery of the energy storage system. Utility Model Content

[0004] The purpose of the utility model is to overcome the defects of the prior art and provide a power replenishment circuit for an energy storage system.

[0005] The utility model provides a power-compensating circuit for an energy storage system, comprising a main charging circuit and a power-compensating circuit, wherein the AC sides of the main charging circuit and the power-compensating circuit are respectively connected to an AC power grid, and the DC sides of the main charging circuit and the power-compensating circuit are respectively connected to a battery cell of an energy storage system;

[0006] The power replenishment circuit is used to pre-charge the depleted battery of the energy storage system using low voltage and low current;

[0007] The power compensation circuit is a single-phase current conversion circuit.

[0008] Furthermore, the power compensation circuit includes a parallel A-phase power conversion topology structure, an N-phase power conversion topology structure and a capacitor branch; the connection point of the A-phase power conversion topology structure is connected to the AC-L side of the AC power grid, and the connection point of the N-phase power conversion topology structure is connected to the AC-N side of the AC power grid.

[0009] Further, a first AC boost inductor is provided on the line connecting the connection point of the A-phase power conversion topology structure and the AC-L side of the AC power grid;

[0010] A second AC boost inductor is provided on a line connecting the connection point of the N-phase power conversion topology structure and the AC-N side of the AC power grid.

[0011] Furthermore, the energy storage system power compensation circuit also includes a control circuit, which includes a controller, a first AC relay and a second AC relay; the first AC relay is arranged between the AC-L side of the AC power grid and the first AC boost inductor, and the second AC relay is arranged between the AC-N side of the AC power grid and the second AC boost inductor.

[0012] Further, the A-phase power conversion topology structure includes six power devices, and the six power devices include a switch tube G1a and a diode D1a, a switch tube G2a and a diode D2a, a switch tube G3a and a diode D3a, a switch tube G4a and a diode D4a, a switch tube G5a and a diode D5a, and a switch tube G6a and a diode D6a;

[0013] The switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a are connected in series in sequence, and the diode D1a, the diode D2a, the diode D3a and the diode D4a are respectively connected in anti-parallel to the switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a; the switch tube G5a and the switch tube G6a are respectively connected to the midpoint of the switch tube G1a and the switch tube G2a, and the midpoint of the switch tube G3a and the switch tube G4a, the switch tube G5a and the switch tube G6a are connected in series, the diode D5a and the diode D6a are respectively connected in anti-parallel to the switch tube G5a and the switch tube G6a, the switch tube G1a is connected to the positive end of the capacitor branch, and the switch tube G4a is connected to the negative end of the capacitor branch; the midpoint of the switch tube G2a and the switch tube G3a is connected to one end of the output end of the main charging circuit.

[0014] Further, the N-phase power conversion topology structure includes six power devices, and the six power devices include a switch tube G1b and a diode D1b, a switch tube G2b and a diode D2b, a switch tube G3b and a diode D3b, a switch tube G4b and a diode D4b, a switch tube G5b and a diode D5b, and a switch tube G6b and a diode D6b;

[0015] The switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b are connected in series in sequence, and the diode D1b, the diode D2b, the diode D3b and the diode D4b are respectively connected in anti-parallel to the switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b; the switch tube G5b and the switch tube G6b are respectively connected to the midpoint of the switch tube G1b and the switch tube G2b, and the midpoint of the switch tube G3b and the switch tube G4b, the switch tube G5b and the switch tube G6b are connected in series, the diode D5b and the diode D6b are respectively connected in anti-parallel to the switch tube G5b and the switch tube G6b, the switch tube G1b is connected to the positive terminal of the capacitor branch, and the switch tube G4b is connected to the negative terminal of the capacitor branch; the midpoint of the switch tube G2b and the switch tube G3b is connected to the other end of the output end of the main charging circuit;

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The utility model has AC sides of a main charging circuit and a supplementary power circuit connected to an AC power grid respectively, and DC sides of the main charging circuit and the supplementary power circuit connected to battery cells of an energy storage system respectively; the AC power of the main charging circuit or the AC power grid is converted into DC power, providing low-voltage and low-current charging for pre-charging of a battery pack of an energy storage system; the main charging circuit or the unidirectional AC power grid shares the supplementary power circuit, and the entire energy storage system does not need to add a supplementary power device, thereby saving the cost of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following drawings are only used to illustrate and explain the present invention, and are not intended to limit the scope of the present invention, wherein:

[0019] Figure 1 : A schematic diagram of the structure of the power supply circuit of the energy storage system of the utility model;

[0020] Figure 2 : A schematic diagram of the structure of the energy storage system power supply circuit in the embodiment of the utility model;

[0021] In the figure: 1—AC relay, 1-1-third AC relay, 1-2-fourth AC relay, 2—AC boost inductor, 2-1-first AC boost inductor, 2-2-second AC boost inductor, 3—A-phase power conversion topology, 4—B-phase power conversion topology, 5—C-phase power conversion topology, 6—N-phase power conversion topology, 7—capacitor branch, 8—three-phase four-wire AC power grid, 9—unidirectional AC power grid. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution, design method and advantages of the utility model clearer, the utility model is further described in detail through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0023] like Figure 1-Figure 2 As shown, the utility model provides a power-compensating circuit for an energy storage system, comprising a main charging circuit and a power-compensating circuit, wherein the AC sides of the main charging circuit and the power-compensating circuit are respectively connected to an AC power grid, and the DC sides of the main charging circuit and the power-compensating circuit are respectively connected to battery cells of an energy storage system;

[0024] The power replenishment circuit is used to pre-charge the depleted battery of the energy storage system using low voltage and low current;

[0025] The power compensation circuit is a single-phase current conversion circuit;

[0026] It should be noted that the present application requires pre-charging of the battery after the energy storage system is deeply discharged or the battery is depleted for a long time; the present invention proposes a unidirectional AC power replenishment scheme with the help of a three-phase four-wire power topology, the main charging circuit includes an AC relay 1 and a three-phase four-wire AC power grid 8, the three-phase four-wire AC power grid 8 can provide four lines of C / B / A / N, in the pre-charging stage, the power bridge arm of the main topology is used, including the A-phase power conversion topology 3, the B-phase power conversion topology 4, the C-phase power conversion topology 5 and the N-phase power conversion topology 6; the A / N phase is selected as the AC input to form a unidirectional rectifier; when pre-charging, the third AC relay 1-1 and the fourth AC relay 1-2 corresponding to the control A / N (or the external unidirectional AC power grid 9 input) are closed, and the AC power is rectified into DC power by controlling the C-phase power conversion topology 5 and the N-phase power conversion topology 6, providing low-voltage and low-current charging for pre-charging of the battery pack; the present application uses a shared power replenishment circuit, and the entire energy storage system does not need to add a power replenishment device, saving the cost of the entire system;

[0027] Further, the power compensation circuit includes an A-phase power conversion topology structure 5, an N-phase power conversion topology structure 6 and a capacitor branch 7 connected in parallel; the connection point of the A-phase power conversion topology structure 5 is connected to the AC-L side of the AC power grid, and the connection point of the N-phase power conversion topology structure 6 is connected to the AC-N side of the AC power grid;

[0028] Furthermore, a first AC boost inductor 2-1 is provided on the line connecting the connection point of the A-phase power conversion topology structure 5 and the AC-L side of the AC power grid;

[0029] A second AC boost inductor 2-2 is provided on the line connected to the AC-N side of the AC power grid of the N-phase power conversion topology structure 6;

[0030] It should be noted that the first AC boost inductor 2-1 and the second AC boost inductor 2-2 cooperate with the capacitor branch 7 to filter and reduce noise of the DC current, and reduce the content of high-frequency harmonics and double frequency current;

[0031] Furthermore, the energy storage system power compensation circuit also includes a control circuit 5, which is a first AC relay and a second AC relay; the first AC relay is arranged between the AC-L side of the AC power grid and the first AC boost inductor, and the second AC relay is arranged between the AC-N side of the AC power grid and the second AC boost inductor.

[0032] Further, the A-phase power conversion topology structure 5 includes six power devices, and the six power devices include a switch tube G1a and a diode D1a, a switch tube G2a and a diode D2a, a switch tube G3a and a diode D3a, a switch tube G4a and a diode D4a, a switch tube G5a and a diode D5a, and a switch tube G6a and a diode D6a;

[0033] The switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a are connected in series in sequence, and the diode D1a, the diode D2a, the diode D3a and the diode D4a are respectively connected in anti-parallel to the switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a; the switch tube G5a and the switch tube G6a are respectively connected to the midpoint of the switch tube G1a and the switch tube G2a, and the midpoint of the switch tube G3a and the switch tube G4a, the switch tube G5a and the switch tube G6a are connected in series, the diode D5a and the diode D6a are respectively connected in anti-parallel to the switch tube G5a and the switch tube G6a, the switch tube G1a is connected to the positive end of the capacitor branch 7, and the switch tube G4a is connected to the negative end of the capacitor branch 7; the midpoint of the switch tube G2a and the switch tube G3a is connected to one end of the output end of the main charging circuit;

[0034] Further, the N-phase power conversion topology structure 6 includes six power devices, and the six power devices include a switch tube G1b and a diode D1b, a switch tube G2b and a diode D2b, a switch tube G3b and a diode D3b, a switch tube G4b and a diode D4b, a switch tube G5b and a diode D5b, and a switch tube G6b and a diode D6b;

[0035] The switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b are connected in series in sequence, and the diode D1b, the diode D2b, the diode D3b and the diode D4b are respectively connected in anti-parallel to the switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b; the switch tube G5b and the switch tube G6b are respectively connected to the midpoint of the switch tube G1b and the switch tube G2b, and the midpoint of the switch tube G3b and the switch tube G4b, the switch tube G5b and the switch tube G6b are connected in series, the diode D5b and the diode D6b are respectively connected in anti-parallel to the switch tube G5b and the switch tube G6b, the switch tube G1b is connected to the positive terminal of the capacitor branch 7, and the switch tube G4b is connected to the negative terminal of the capacitor branch 7; the midpoint of the switch tube G2b and the switch tube G3b is connected to the other end of the output end of the main charging circuit;

[0036] It is worth noting that the present application requires pre-charging of the battery after the energy storage system is deeply discharged or the battery is depleted for a long time; in the pre-charging stage, the power bridge arm of the main topology of the main charging circuit is used to select the A / N phase as the AC input to form a unidirectional rectifier; when pre-charging, the AC sides of the main charging circuit and the supplementary power circuit are respectively connected to the AC power grid, and the DC sides of the main charging circuit and the supplementary power circuit are respectively connected to the battery cells of the energy storage system; the third AC relay 1-1 and the fourth AC relay 1-2 corresponding to the control A / N (or the external unidirectional AC power grid 9 input) are closed, and by controlling the C-phase power conversion topology 5 and the N-phase power conversion topology 6, the AC power is rectified into DC power to provide low-voltage and low-current charging for the pre-charging of the energy storage system battery pack. By sharing the supplementary power circuit, the entire energy storage system does not need to add a supplementary power device, saving the cost of the entire system.

[0037] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A power supply circuit for an energy storage system, characterized in that: It includes a main charging circuit and a supplementary power circuit, wherein the AC sides of the main charging circuit and the supplementary power circuit are respectively connected to the AC power grid, and the DC sides of the main charging circuit and the supplementary power circuit are respectively connected to the battery cells of the energy storage system; The power replenishment circuit is used to pre-charge the depleted battery of the energy storage system using low voltage and low current; The power compensation circuit is a single-phase current conversion circuit.

2. The energy storage system power supply circuit according to claim 1, characterized in that: The power compensation circuit includes a parallel A-phase power conversion topology structure, an N-phase power conversion topology structure and a capacitor branch; the connection point of the A-phase power conversion topology structure is connected to the AC-L side of the AC power grid, and the connection point of the N-phase power conversion topology structure is connected to the AC-N side of the AC power grid.

3. The energy storage system power compensation circuit according to claim 2, characterized in that: A first AC boost inductor is provided on a line connecting the connection point of the A-phase power conversion topology structure and the AC-L side of the AC power grid; A second AC boost inductor is provided on a line connecting the connection point of the N-phase power conversion topology structure and the AC-N side of the AC power grid.

4. The energy storage system power supply circuit according to claim 3, characterized in that: The energy storage system power compensation circuit also includes a control circuit, which includes a controller, a first AC relay and a second AC relay; the first AC relay is arranged between the AC-L side of the AC power grid and the first AC boost inductor, and the second AC relay is arranged between the AC-N side of the AC power grid and the second AC boost inductor.

5. The energy storage system power compensation circuit according to claim 2, characterized in that: The A-phase power conversion topology structure includes six power devices, which include a switch tube G1a and a diode D1a, a switch tube G2a and a diode D2a, a switch tube G3a and a diode D3a, a switch tube G4a and a diode D4a, a switch tube G5a and a diode D5a, and a switch tube G6a and a diode D6a. The switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a are connected in series in sequence, and the diode D1a, the diode D2a, the diode D3a and the diode D4a are respectively connected in anti-parallel to the switch tube G1a, the switch tube G2a, the switch tube G3a and the switch tube G4a; the switch tube G5a and the switch tube G6a are respectively connected to the midpoint of the switch tube G1a and the switch tube G2a, and the midpoint of the switch tube G3a and the switch tube G4a, the switch tube G5a and the switch tube G6a are connected in series, the diode D5a and the diode D6a are respectively connected in anti-parallel to the switch tube G5a and the switch tube G6a, the switch tube G1a is connected to the positive end of the capacitor branch, and the switch tube G4a is connected to the negative end of the capacitor branch; the midpoint of the switch tube G2a and the switch tube G3a is connected to one end of the output end of the main charging circuit.

6. The energy storage system power compensation circuit according to claim 2, characterized in that: The N-phase power conversion topology structure includes six power devices, which include a switch tube G1b and a diode D1b, a switch tube G2b and a diode D2b, a switch tube G3b and a diode D3b, a switch tube G4b and a diode D4b, a switch tube G5b and a diode D5b, and a switch tube G6b and a diode D6b; The switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b are connected in series in sequence, and the diode D1b, the diode D2b, the diode D3b and the diode D4b are respectively connected in anti-parallel to the switch tube G1b, the switch tube G2b, the switch tube G3b and the switch tube G4b; the switch tube G5b and the switch tube G6b are respectively connected to the midpoint of the switch tube G1b and the switch tube G2b, and the midpoint of the switch tube G3b and the switch tube G4b, the switch tube G5b and the switch tube G6b are connected in series, the diode D5b and the diode D6b are respectively connected in anti-parallel to the switch tube G5b and the switch tube G6b, the switch tube G1b is connected to the positive terminal of the capacitor branch, and the switch tube G4b is connected to the negative terminal of the capacitor branch; the midpoint of the switch tube G2b and the switch tube G3b is connected to the other end of the output end of the main charging circuit.

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