CN209982087U - Modular multi-level energy storage system - Google Patents
Modular multi-level energy storage system Download PDFInfo
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- CN209982087U CN209982087U CN201920827400.8U CN201920827400U CN209982087U CN 209982087 U CN209982087 U CN 209982087U CN 201920827400 U CN201920827400 U CN 201920827400U CN 209982087 U CN209982087 U CN 209982087U
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Abstract
The utility model discloses a many level of modularization energy storage system, including main control unit, from controller, three-phase circuit and grid-connected reactor, first phase circuit includes three level energy storage module, battery cell, high-pressure H bridge module, and each group battery cell includes first battery and second battery, and the positive pole of series connection branch road connects the positive input end of three level energy storage module, and the negative pole of series connection branch road connects the negative pole input end of three level energy storage module, and the neutral input end of three level energy storage module is connected between first battery and second battery; the output ends of the three-level energy storage modules are sequentially connected in series, the output end of the three-level energy storage module arranged at the head is connected with the positive input end of the high-voltage H-bridge module, and the output end of the three-level energy storage module arranged at the tail is connected with the negative input end of the high-voltage H-bridge module. The utility model can avoid the direct series connection of the batteries; each energy storage module can output three-level voltage, the number of the used energy storage modules and controllers thereof can be reduced by half, and the cost is reduced.
Description
Technical Field
The utility model relates to an energy storage technology field especially relates to a many level of modularization energy storage system.
Background
At present, with the wide application of new energy power generation, the position of energy storage in a power system is more and more important. The commonly used energy storage battery monomers are directly used in series and parallel connection, and the requirement on the consistency of the battery is high. The fault-tolerant capability is poor, and the problems of series voltage sharing and parallel current sharing exist, so that the efficiency is low. The modular energy storage technology is characterized in that a low-voltage battery unit controlled by a power electronic converter is used as an independent module and is connected in series to be grouped to output high voltage, the modular energy storage technology is a flexible battery grouping technology, each energy storage module can independently control the charging and discharging and SOC, a large number of batteries can be directly connected in series, batteries with different specifications and different old and new degrees can be used, the gradient utilization of waste batteries is realized, and a battery energy management system does not need to be additionally configured.
However, the existing solutions have the following drawbacks:
the main disadvantage of the above-mentioned modular energy storage technology is that the number of energy storage modules is large, and each energy storage module needs to be configured with an independent control unit, which is relatively high in cost.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model aims to provide a modular multilevel energy storage system, which can solve the technical problems that the number of energy storage modules is large and each energy storage module needs to be independently controlled in the prior art.
The utility model discloses a following technical scheme realizes:
a modular multilevel energy storage system is characterized by comprising a master controller, a plurality of slave controllers, a three-phase circuit and grid-connected reactors corresponding to the three-phase circuit one by one, the three-phase circuit comprises a first phase circuit, a second phase circuit and a third phase circuit, wherein the first phase circuit comprises a plurality of three-level energy storage modules, a plurality of groups of battery units and a high-voltage H-bridge module, the three-level energy storage modules correspond to the battery units one by one, each group of the battery units comprises a first battery and a second battery which are sequentially connected in series to form a series branch, the anode of the series branch is connected with the anode input end of the three-level energy storage module, the cathode of the series branch is connected with the cathode input end of the three-level energy storage module, the neutral input end of the three-level energy storage module is connected between the first battery and the second battery; between two adjacent three-level energy storage modules, the negative output end of the previous three-level energy storage module is connected with the positive output end of the next three-level energy storage module, the positive output end of the first three-level energy storage module is connected with the positive input end of the high-voltage H-bridge module, and the output end of the last three-level energy storage module is connected with the negative input end of the high-voltage H-bridge module; the first output end of the high-voltage H-bridge module, the first output end of the second phase circuit and the first output end of the third phase circuit are connected with an external alternating current power grid through the corresponding grid-connected reactors, and the second output end of the high-voltage H-bridge module, the second output end of the second phase circuit and the second output end of the third phase circuit are connected with a common connecting end; the three-level energy storage module and the high-voltage H-bridge module are respectively connected with corresponding slave controllers, and the slave controllers corresponding to the first-phase circuit, the second-phase circuit and the third-phase circuit are respectively connected with the master controller.
Further, the three-level energy storage module comprises a capacitor C1, a capacitor C2, a controllable switch S1, a controllable switch S2, a controllable switch S3 and a controllable switch S4, an emitter of the controllable switch S1 is connected to a collector of the controllable switch S2, an emitter of the controllable switch S2 is connected to a collector of the controllable switch S3, an emitter of the controllable switch S3 is connected to a collector of the controllable switch S4, a collector of the controllable switch S1 is connected to a positive pole of the series branch, an emitter of the controllable switch S4 is connected to a negative pole of the series branch, the neutral input is located between the emitter of the controllable switch S2 and the collector of the controllable switch S3, a positive input of the high-voltage H-bridge module is connected between the emitter of the controllable switch S1 and the collector of the controllable switch S2, and a negative input of the high-voltage H-bridge module is connected between the emitter of the controllable switch S3 and the collector of the controllable switch S4 (ii) a One end of the capacitor C1 is connected to the collector of the controllable switch S1, the other end of the capacitor C1 is connected to the emitter of the controllable switch S4 through the capacitor C2, and the base of the controllable switch S1, the base of the controllable switch S2, the base of the controllable switch S3 and the base of the controllable switch S4 are all connected to the slave controller.
Further, the high voltage H-bridge module is a full-bridge converter, and includes a capacitor C3, a high voltage switch S5, a high voltage switch S6, a high voltage switch S7, and a high voltage switch S8, a collector of the high voltage switch S5 and a collector of the high voltage switch S7 are connected as a positive input terminal of the high voltage H-bridge module, an emitter of the high voltage switch S6 and an emitter of the high voltage switch S8 are connected as a negative input terminal of the high voltage H-bridge module, an emitter of the high voltage switch S5 and a collector of the high voltage switch S6 are connected as a first output terminal of the high voltage H-bridge module, an emitter of the high voltage switch S7 and a collector of the high voltage switch S8 are connected as a second output terminal of the high voltage H-bridge module, one end of the capacitor C3 is connected to the collector of the high voltage switch S5, and the other end is connected to an emitter of, the slave controller controls the turn-on and turn-off of the high voltage switch S5, the high voltage switch S6, the high voltage switch S7, and the high voltage switch S8.
Further, the master controller comprises a communication module, a grid-connected vector control module, an SOC balance module, a PWM signal generation module and a master-slave interaction module, the communication module, the grid-connected vector control module, the SOC balance module, the PWM signal generation module and the master-slave interaction module are sequentially connected, and slave controllers corresponding to the first phase circuit, the second phase circuit and the third phase circuit respectively are all connected with the master controller.
Compared with the prior art, the beneficial effects of the utility model reside in that:
the utility model discloses each energy storage module can insert two batteries to independently control charging and discharging to the battery, avoid the direct series connection of battery; each energy storage module can output three-level voltage, the number of used energy storage modules and controllers thereof can be reduced by half, the cost is greatly reduced, the wiring is simple, only three cables are needed to be connected to the energy storage modules after two groups of batteries of each module are connected in series, and the number of the cables can be reduced by 25% compared with the number of cables adopting two-level modules.
Drawings
Fig. 1 is a block diagram of the overall module of a modular multilevel energy storage system according to the present invention;
FIG. 2 is a connection structure diagram of a three-phase circuit and a grid-connected reactor of the present invention;
fig. 3 is a circuit structure diagram of the three-level energy storage module of the present invention;
fig. 4 is a circuit structure diagram of the high-voltage H-bridge module of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that the embodiments or technical features described below can be arbitrarily combined to form a new embodiment without conflict.
As shown in fig. 1 and 2, the utility model provides a many level energy storage system of modularization, including main control unit, a plurality of from controller, three-phase circuit and with the reactor L that is incorporated into the power networks of three-phase circuit one-to-one. The three-phase circuit comprises a first phase circuit, a second phase circuit and a third phase circuit, wherein the first phase circuit comprises a plurality of three-level energy storage modules, a plurality of groups of battery units and a high-voltage H-bridge module, and the three-level energy storage modules correspond to the battery units one to one. The number of the battery units is equal to that of the three-level energy storage modules.
Specifically, each group the battery unit all includes two batteries, is marked as first battery B1 and second battery B2 in the utility model discloses, first battery B1 and second battery B2 series connection form the series branch road. The anode of the series branch is connected with the anode input end X1 of the three-level energy storage module, the cathode of the series branch is connected with the cathode input end X3 of the three-level energy storage module, the neutral input end X2 of the three-level energy storage module is connected between two adjacent three-level energy storage modules between the first battery B1 and the second battery B2, the cathode output end of the previous three-level energy storage module is connected with the anode output end of the next three-level energy storage module, the anode output end of the first three-level energy storage module is connected with the anode input end of the high-voltage H-bridge module, and the output end of the last three-level energy storage module is connected with the cathode input end of the high-voltage H-bridge module; the first output end of the high-voltage H-bridge module, the first output end of the second phase circuit and the first output end of the third phase circuit are connected with an external alternating current power grid through the corresponding grid-connected reactors L, the second output end of the high-voltage H-bridge module, the second output end of the second phase circuit and the second output end of the third phase circuit are connected with a public connecting end, the three-level energy storage module and the high-voltage H-bridge module are respectively connected with corresponding slave controllers, and the slave controllers corresponding to the first phase circuit, the second phase circuit and the third phase circuit are respectively connected with the master controller. That is, each three-level energy storage module corresponds to a different slave controller, and each three-level energy storage module and the high-voltage H-bridge module correspond to different slave controllers respectively. And the second phase circuit and the third phase circuit are also assigned corresponding slave controllers.
In fact, each three-level energy storage module has a positive output terminal X4 and a negative output terminal X5, the three-level energy storage modules are arranged in sequence, the negative output terminal X5 of the previous three-level energy storage module is connected with the positive output terminal X4 of the next adjacent three-level energy storage module, and so on, the positive output terminal X4 of the first three-level energy storage module is connected with the positive input terminal of the high-voltage H-bridge module, and the negative output terminal X5 of the last three-level energy storage module is connected with the negative input terminal of the high-voltage H-bridge membrane module. The slave controllers are connected with the three-level energy storage modules in a one-to-one correspondence mode, and the slave controllers are connected with the master controller.
Specifically, the master controller comprises a communication module, a grid-connected vector control module, an SOC balance module, a PWM signal generation module and a master-slave interaction module, the communication module, the grid-connected vector control module, the SOC balance module, the PWM signal generation module and the master-slave interaction module are sequentially connected, and the slave controller, the second phase circuit and the third phase circuit are all connected with the master-slave interaction module.
The communication module receives grid connection and Charge-discharge power instructions, the grid connection control module calculates output reference voltage uref by adopting a closed-loop control algorithm according to detected voltage, current and Charge-discharge power of a power grid, the SOC (State of Charge, also called residual electric quantity) balancing module is used for controlling SOC balance of all battery units by adopting algorithms such as sequencing or PI control, the PWM signal generation module is used for generating control signals of all three-level energy storage modules by adopting carrier phase shift PWM or carrier stacking PWM, and the master-slave interaction module is used for sending out the control signals of all three-level energy storage modules and receiving State feedback signals such as voltage, current and temperature of a slave controller. Each three-level energy storage module is provided with a slave controller, and the slave controller is used for receiving a switch signal sent by the master controller, controlling the on or off of each switch through a driving circuit, and detecting state signals of the battery such as voltage, current and temperature and feeding back the state signals to the master controller.
The specific structure of the three-level energy storage module is shown in fig. 3, and it includes a capacitor C1, a capacitor C2, a controllable switch S1, a controllable switch S2, a controllable switch S3 and a controllable switch S4, an emitter of the controllable switch S1 is connected to a collector of the controllable switch S2, an emitter of the controllable switch S2 is connected to a collector of the controllable switch S3, an emitter of the controllable switch S3 is connected to a collector of the controllable switch S4, a collector of the controllable switch S1 is connected to an anode of the series branch, that is, to an anode input terminal X1 of the three-level energy storage module, an emitter of the controllable switch S4 is connected to a cathode of the series branch, that is, to a cathode input terminal X3 of the three-level energy storage module, the neutral input terminal is located between the emitter of the controllable switch S2 and the collector of the controllable switch S3, and an anode input terminal 2 of the controllable switch S1 and the emitter of the controllable switch S2S 3 of the high-level energy storage module The negative input end of the high-voltage H-bridge module is connected between the emitter of the controllable switch S3 and the collector of the controllable switch S4; one end of the capacitor C1 is connected to the collector of the controllable switch S1, the other end of the capacitor C1 is connected to the emitter of the controllable switch S4 via the capacitor C2, and the slave controller controls the on and off of the controllable switch S2, the controllable switch S3, and the controllable switch S4 of the controllable switch S1.
The working principle of the three-level energy storage module is that the control signals of the controllable switch S1 and the controllable switch S2 are complementary, and the control signals of the controllable switch S3 and the controllable switch S4 are complementary. Assuming that the voltage of the first battery and the voltage of the second battery in a group of battery units are U1 and U2, respectively, when the controllable switch S1 and the controllable switch S3 are turned on, the first battery is turned on, the output voltage Vo is U1, the controllable switch S2 and the controllable switch S4 are turned on, the second battery is turned on, the output voltage Vo is U2, when the controllable switch S2 and the controllable switch S3 are turned on, the two batteries are not turned on, the output voltage Vo is 0, and when the controllable switch S1 and the controllable switch S4 are turned on, the two batteries are connected in series and then turned on, and the output voltage Vo is U1+ U2. Since U1 and U2 are close, the output voltage is three-level.
The controllable switch on each three-level energy storage module adopts a full-control power switch device, and power semiconductor switch sources with corresponding levels, such as IGBT or MOSFET, are selected according to different output voltage levels.
The utility model discloses a high pressure H bridge module is preferably full-bridge converter. Referring to fig. 4, a specific structure of the high voltage H-bridge module includes a capacitor C3, a high voltage switch S5, a high voltage switch S6, a high voltage switch S7, and a high voltage switch S8, wherein a collector of the high voltage switch S5 and a collector of the high voltage switch S7 are connected as a positive input terminal of the high voltage H-bridge module, an emitter of the high voltage switch S6 and an emitter of the high voltage switch S8 are connected as a negative input terminal of the high voltage H-bridge module, an emitter of the high voltage switch S5 and a collector of the high voltage switch S6 are connected as a first output terminal of the high voltage H-bridge module, an emitter of the high voltage switch S7 and a collector of the high voltage switch S8 are connected as a second output terminal of the high voltage H-bridge module, one end of the capacitor C3 is connected to the collector of the high voltage switch S5, the other end is connected to an emitter of the high voltage switch S6, and, The high voltage switch S6, the high voltage switch S7, and the high voltage switch S8.
The working principle of the high-voltage H-bridge module is as follows: the control signals of the high-voltage switch S5 and the high-voltage switch S6 are complementary, and the control signals of the high-voltage switch S7 and the high-voltage switch S8 are complementary. Assuming that the output voltage of the n three-level energy storage modules after being connected in series is Up, when the high-voltage switch S5 and the high-voltage switch S8 are turned on, the positive voltage Vo is Up, and when the high-voltage switch S6 and the high-voltage switch S7 are turned on, the negative voltage Vo is Up. By the working mode, the multi-level direct-current voltage output by the three-level energy storage modules after being connected in series is converted into the multi-level alternating-current voltage.
Similarly, the high-voltage switch also adopts a full-control power switch device, and power semiconductor switch elements with corresponding grades, such as IGBT or MOSFET, are selected according to different output voltage grades.
The working principle of the utility model is, obtain three-phase reference voltage urefa, urefb and urefc according to outside grid-connected control algorithm, when this looks reference voltage urefx (wherein x indicates three-phase serial number a, b or c) is greater than 0, the S1 and S4 of high pressure H bridge module switch on, and the output is positive, and when this looks reference voltage urefx is less than 0, the S2 and S3 of high pressure H bridge module switch on, and the output is the burden. The absolute value of the total output reference voltage urefx of the n three-level energy storage modules of each phase is always positive, and since the output voltage of each three-level energy storage module can be 0, or can be one battery voltage or two battery voltages, the number of batteries required to be connected can be calculated according to the absolute value of urefx and the size of the battery voltage in each control period. In order to equalize the SOCs (residual capacities) of all the battery cells, it is necessary to perform a sequence control of the voltages or SOCs of all the battery cells, such that the battery cell having a lower voltage or SOC is accessed first when the energy storage system is charged, and the battery cell having a higher voltage or SOC is accessed first when the energy storage system is discharged.
The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention cannot be limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are all within the protection scope of the present invention.
Claims (4)
1. A modular multilevel energy storage system is characterized by comprising a master controller, a plurality of slave controllers, a three-phase circuit and grid-connected reactors corresponding to the three-phase circuit one by one, the three-phase circuit comprises a first phase circuit, a second phase circuit and a third phase circuit, wherein the first phase circuit comprises a plurality of three-level energy storage modules, a plurality of groups of battery units and a high-voltage H-bridge module, the three-level energy storage modules correspond to the battery units one by one, each group of the battery units comprises a first battery and a second battery which are sequentially connected in series to form a series branch, the anode of the series branch is connected with the anode input end of the three-level energy storage module, the cathode of the series branch is connected with the cathode input end of the three-level energy storage module, the neutral input end of the three-level energy storage module is connected between the first battery and the second battery; between two adjacent three-level energy storage modules, the negative output end of the previous three-level energy storage module is connected with the positive output end of the next three-level energy storage module, the positive output end of the first three-level energy storage module is connected with the positive input end of the high-voltage H-bridge module, and the output end of the last three-level energy storage module is connected with the negative input end of the high-voltage H-bridge module; the first output end of the high-voltage H-bridge module, the first output end of the second phase circuit and the first output end of the third phase circuit are connected with an external alternating current power grid through the corresponding grid-connected reactors, and the second output end of the high-voltage H-bridge module, the second output end of the second phase circuit and the second output end of the third phase circuit are connected with a common connecting end; the three-level energy storage module and the high-voltage H-bridge module are respectively connected with corresponding slave controllers, and the slave controllers corresponding to the first-phase circuit, the second-phase circuit and the third-phase circuit are respectively connected with the master controller.
2. The modular multilevel energy storage system according to claim 1, wherein the three-level energy storage module comprises a capacitor C1, a capacitor C2, a controllable switch S1, a controllable switch S2, a controllable switch S3 and a controllable switch S4, an emitter of the controllable switch S1 is connected to a collector of the controllable switch S2, an emitter of the controllable switch S2 is connected to a collector of the controllable switch S3, an emitter of the controllable switch S3 is connected to a collector of the controllable switch S4, a collector of the controllable switch S1 is connected to a positive pole of the series branch, an emitter of the controllable switch S4 is connected to a negative pole of the series branch, the neutral input is located between the emitter of the controllable switch S2 and the collector of the controllable switch S3, a positive input of the high voltage H-bridge module is connected between the emitter of the controllable switch S1 and the collector of the controllable switch S2, the negative input end of the high-voltage H-bridge module is connected between the emitter of the controllable switch S3 and the collector of the controllable switch S4; one end of the capacitor C1 is connected to the collector of the controllable switch S1, the other end of the capacitor C1 is connected to the emitter of the controllable switch S4 via the capacitor C2, and the slave controller controls the on and off of the controllable switch S1, the controllable switch S2, the controllable switch S3 and the controllable switch S4.
3. The modular multilevel energy storage system of claim 2, wherein the high voltage H-bridge module is a full-bridge converter comprising a capacitor C3, a high voltage switch S5, a high voltage switch S6, a high voltage switch S7, and a high voltage switch S8, wherein a collector of the high voltage switch S5 and a collector of the high voltage switch S7 are connected as positive input terminals of the high voltage H-bridge module, an emitter of the high voltage switch S6 and an emitter of the high voltage switch S8 are connected as negative input terminals of the high voltage H-bridge module, an emitter of the high voltage switch S5 and a collector of the high voltage switch S6 are connected as first output terminals of the high voltage H-bridge module, an emitter of the high voltage switch S7 and a collector of the high voltage switch S8 are connected as second output terminals of the high voltage H-bridge module, one end of the capacitor C3 is connected to a collector of the high voltage switch S5, the other end of the high-voltage switch S6 is connected with the emitter of the high-voltage switch S6, and the slave controller controls the high-voltage switch S5, the high-voltage switch S6, the high-voltage switch S7 and the high-voltage switch S8 to be switched on and off.
4. The modular multilevel energy storage system according to claim 3, wherein the master controller comprises a communication module, a grid-connected vector control module, an SOC balance module, a PWM signal generation module and a master-slave interaction module, the communication module, the grid-connected vector control module, the SOC balance module, the PWM signal generation module and the master-slave interaction module are sequentially connected, and the slave controllers corresponding to the first phase circuit, the second phase circuit and the third phase circuit respectively are connected with the master controller.
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