Energy storage system power output control method and energy storage system

Abstract

The invention relates to an energy storage system power output control method and an energy storage system. The energy storage system comprises three single-phase input modules used for being connected with the single-phase energy storage system and a three-phase output module used for providing three-phase output. The method comprises the following steps: when all single-phase input modules have power supply input, controlling one single-phase input module through a first square wave at a first time point; and starting to output a second square wave at a second time point after the first time point and starting to output a third square wave at a third time point after the first time point so as to control the remaining two single-phase input modules through the second square wave and the third square wave respectively, the phase differences between the second square wave and the first square wave and between the third square wave and the first square wave are 120 degrees and 240 degrees respectively, and the duty ratios are the same; and controlling all the single-phase input modules and the three-phase output modules to be in one-to-one correspondence and to be simultaneously conducted, so as to provide three-phase output through the three-phase output modules. According to the invention, the portability of the single-phase energy storage system can be satisfied, and the three-phase output requirement can be satisfied at the same time.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically, to a power output control method and an energy storage system. Background Technology

[0002] Energy storage systems are widely used in home backup power, emergency power, and outdoor power supplies, converting battery energy into AC power required by the loads in these applications. Three-phase energy storage systems can power both single-phase and three-phase devices, but they are typically large, expensive, and not portable. Single-phase energy storage systems are usually small, portable, and inexpensive, but they cannot power three-phase appliances. In other words, while a single-phase energy storage system outputting single-phase AC power can handle most scenarios, it struggles to power three-phase devices. For example, some villa power supplies, three-phase charging stations, and specialized instruments use three-phase power. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a power output control method and an energy storage system for energy storage systems, addressing the aforementioned technical deficiencies of the prior art.

[0004] The technical solution adopted by this invention to solve its technical problem is: constructing a power output control method for an energy storage system, wherein the energy storage system includes: three single-phase input modules for connecting a single-phase energy storage system, and a three-phase output module for providing three-phase output; the method includes: When all the single-phase input modules have power input, a first square wave is generated at a first time point to control the power output of one of the single-phase input modules through the first square wave; A second square wave is generated at a second time point after the first time point, and a third square wave is generated at a third time point after the first time point, so as to control the power output of the remaining two single-phase input modules respectively through the second square wave and the third square wave; wherein, the duty cycle of the second square wave and the third square wave is the same as that of the first square wave, so that the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively. All the single-phase input modules are controlled to correspond one-to-one with the three-phase output modules and be turned on simultaneously, so as to provide three-phase output through the three-phase output modules.

[0005] Preferably, in one embodiment of the power output control method for an energy storage system according to the present invention, the energy storage system further includes a three-phase input module connected to the three-phase power grid input, and the method further includes: The phase voltage of any phase in the three-phase power grid is obtained, so as to obtain the first time point based on the phase voltage of the phase.

[0006] Preferably, in one embodiment of the power output control method for an energy storage system according to the present invention, the step of obtaining the phase voltage of any phase in the three-phase power grid to obtain the first time point based on the phase voltage of the phase includes: The phase voltage amplitude of the phase is monitored, and the time point corresponding to when the phase voltage amplitude of the phase is a preset value is taken as the first time point.

[0007] Preferably, in one embodiment of the power output control method for the energy storage system according to the present invention, the preset value ranges from 176 to 264V.

[0008] Preferably, in one embodiment of the power output control method for an energy storage system according to the present invention, the method further includes: Monitor the power supply status of the single-phase input modules, and when the power supply input of any single-phase input module is abnormal, control all single-phase input modules and the three-phase output modules to be turned off.

[0009] Preferably, in one embodiment of the power output control method for the energy storage system according to the present invention, the amplitudes of the first square wave, the second square wave, and the third square wave are substantially the same.

[0010] Preferably, in one embodiment of the power output control method for the energy storage system described in this invention, the duty cycles of the first square wave, the second square wave, and the third square wave are all 50%.

[0011] The present invention also provides an energy storage system, comprising: three single-phase input modules for connecting a single-phase energy storage system; a three-phase output module for providing three-phase output; and a control module, the control module being used for: When all the single-phase input modules have power input, a first square wave is generated at a first time point to control the power output of one of the single-phase input modules through the first square wave; A second square wave is generated at a second time point after the first time point, and a third square wave is generated at a third time point after the first time point, so as to control the power output of the remaining two single-phase input modules respectively through the second square wave and the third square wave; wherein, the second square wave and the third square wave have the same duty cycle as the first square wave, and the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively. All the single-phase input modules are controlled to correspond one-to-one with the three-phase output modules and be turned on simultaneously, so as to provide three-phase output through the three-phase output modules.

[0012] Preferably, in one embodiment of the energy storage system of the present invention, the energy storage system further includes a three-phase input module connected to the three-phase power grid input; the control module is further configured to: The phase voltage of any phase in the three-phase power grid is obtained, so as to obtain the first time point based on the phase voltage of the phase.

[0013] Preferably, in one embodiment of the energy storage system of the present invention, the control module is further configured to: Monitor the power supply status of the single-phase input modules, and when the power supply input of any single-phase input module is abnormal, control all single-phase input modules and the three-phase output modules to be turned off.

[0014] The energy storage system power output control method and energy storage system of the present invention have the following beneficial effects: multiple single-phase energy storage systems can be combined into a distributed three-phase energy storage system, which satisfies the portability of single-phase energy storage systems while meeting the requirements of three-phase output. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a flowchart of an embodiment of a power output control method for an energy storage system according to the present invention; Figure 2 This is a schematic diagram of an embodiment of an energy storage system; Figure 3 This is a schematic diagram of another embodiment of an energy storage system; Figure 4 This is a flowchart of another embodiment of the power output control method for an energy storage system according to the present invention; Figure 5 This is a flowchart of another embodiment of the power output control method for an energy storage system according to the present invention; Figure 6 This is a wiring diagram of an embodiment of a power output control method for an energy storage system. Detailed Implementation

[0016] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] like Figure 1 As shown, an embodiment of a power output control method for an energy storage system according to the present invention is illustrated. Figure 2 As shown, the energy storage system includes: three single-phase input modules 120 for connecting to the single-phase energy storage system, and a three-phase output module 150 for providing three-phase output. Figure 1In an embodiment of the power output control method for an energy storage system of the present invention, the method includes: S1, when all single-phase input modules 120 have power input, generating a first square wave at a first time point to control the power output of one single-phase input module 120; S2, generating a second square wave at a second time point after the first time point and a third square wave at a third time point after the first time point to control the power output of the remaining two single-phase input modules respectively; wherein the duty cycle of the second square wave, the third square wave and the first square wave are the same, and the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively; S3, controlling all single-phase input modules 120 to correspond one-to-one with the three-phase output module 150 and simultaneously turn on to provide three-phase output through the three-phase output module 150.

[0018] Based on step S1, when the energy storage system needs to connect a single phase to three phases, the power supply input of the three single-phase input modules 120 is first determined. Since the entire grid connection process relies on the power input of the three single-phase input modules 120, power output can only proceed normally when all three modules have power supply input. When it can be determined that all three modules have power supply input, one module can be selected as the first input module, and a first square wave is output at the first time point. The power output process of this first input module is controlled by the first square wave. The process of the single-phase input module 120 outputting power according to the square wave is as follows: power output begins during the high-level phase of the square wave and is turned off during the low-level phase. This ensures that the single-phase input module 120 outputs an AC output corresponding to the square wave period. Simultaneously, the process of controlling the single-phase input module 120 via the square wave can send corresponding signals to the corresponding devices through the communication circuit in the energy storage system.

[0019] Based on step S2, one of the remaining two single-phase input modules 120 is selected as the second input module. A second square wave is generated starting at the second time point after the first time point to control the power output of this second input module. The power output process can refer to the square wave control process of the single-phase input module 120 described above. The last remaining module is selected as the third input module. Starting at the third time point after the first time point, the third input module is controlled by a third square wave to output power. The power output process can refer to the square wave control process of the single-phase input module 120 described above, where the duty cycles of the first, second, and third square waves are the same, and their corresponding frequencies or high / low levels can also be the same. Simultaneously, by controlling the relationship between the first, second, and third time points, the phase difference between each pair of the first, second, and third square waves is made 120 degrees, thus approximating a three-phase power input. In one embodiment, the second time point can be set to approximately 6.67 ms after the first time point, and the third time point to approximately 13.33 ms after the first time point.

[0020] In one embodiment, the amplitudes of the first square wave, the second square wave, and the third square wave are substantially the same. That is, in order to ensure that the three-phase output power output by the three-phase output module 150 is in a stable state, the amplitudes of the first square wave, the second square wave, and the third square wave need to be set to be substantially the same.

[0021] In one embodiment, the duty cycles of the first square wave, the second square wave, and the third square wave are all 50%. Considering that the ratio of the positive half-cycle and the negative half-cycle of the AC power grid is 50% each, a square wave with a duty cycle of 50% can be specifically set, wherein the high level of the square wave, for example 3.3V, corresponds to the positive half-cycle of the power grid, and the low level of the square wave, for example 0V, corresponds to the negative half-cycle of the power grid.

[0022] Based on step S3, after obtaining the outputs of the three single-phase input modules 120, the three single-phase input modules 120 are simultaneously connected to the three phases of the three-phase output module 150 in a one-to-one correspondence. For example, the first input module is connected to phase A of the three-phase output module 150, the second input module is connected to phase B of the three-phase output module 150, the third input module is connected to phase C of the three-phase output module 150, and the negative terminals of the three single-phase input modules 120 are connected to the neutral (N) line of the three-phase output module 150. This ultimately achieves three-phase output through the three-phase output module 150. In one embodiment, a switching module 140 can be provided to switch the connection states of the three single-phase input modules 120 and the three-phase output module 150. During the specific operation of the single-phase input modules 120 and the three-phase output module 150, voltage and current monitoring can be performed as needed, and specific voltage and current control processes can be implemented.

[0023] like Figure 3 As shown, the energy storage system also includes a three-phase input module 110 connected to the three-phase power grid input, such as... Figure 4 As shown, the method of the present invention further includes: S0, acquiring the phase voltage of any phase in the three-phase power grid, so as to obtain a first time point based on the phase voltage of the phase. Specifically, in the energy storage system, a three-phase input module 110 is set up to provide power to the three-phase output module 150 as needed. At this time, in order to ensure that the output power of the three-phase output module 150 does not become abnormal when the three single-phase input modules 120 are connected to the grid, one phase of the three-phase power grid input is selected as the reference phase, and the first input module of the three single-phase input modules 120 is aligned with the phase of the reference phase, that is, the phase voltage of one phase in the three-phase power grid is monitored, and the first time point is obtained based on the phase voltage of the phase.

[0024] In one embodiment, acquiring the phase voltage of any phase in a three-phase power grid to obtain a first time point based on the phase voltage includes: monitoring the phase voltage amplitude of the phase and acquiring the time point corresponding to when the phase voltage amplitude of the phase is a preset value as the first time point. Specifically, the change in the phase voltage amplitude of a selected reference phase in the three-phase power grid can be continuously monitored, and the time point corresponding to when the phase voltage amplitude is a preset value can be taken as the first time point. In a specific embodiment, if the preset value is within a reasonable range, such as 176-264V, that is, when the phase voltage of the reference phase is within this range, the generation of a first square wave to control the first input module to generate a first square wave is initiated.

[0025] like Figure 5 In one embodiment, the power output control method of the energy storage system of the present invention further includes: S4, monitoring the power supply status of the single-phase input module 120, and controlling all single-phase input modules 120 and the three-phase output module 150 to shut down when the power supply input of any single-phase input module 120 is abnormal. Specifically, in order to ensure that the three-phase output module 150 can provide three-phase output normally, during the operation of the three-phase output module 150, the power supply status of each single-phase input module 120 is continuously monitored. When any one or more single-phase input modules 120 experience a power supply input abnormality, all single-phase input modules 120 are controlled to shut down the three-phase output module 150, so as to ultimately shut down the output of the three-phase output module 150 and avoid output imbalance leading to abnormal downstream load.

[0026] Additionally, such as Figure 2As shown, in one embodiment of an energy storage system of the present invention, three single-phase input modules 120 are used to connect a single-phase energy storage system, a three-phase output module 150 is used to provide three-phase output, and a control module 130 is used. The control module 130 is used to: generate a first square wave at a first time point when all single-phase input modules have power input, so as to control the power output of one single-phase input module through the first square wave; generate a second square wave at a second time point after the first time point and generate a third square wave at a third time point after the first time point, so as to control the power output of the remaining two single-phase input modules through the second square wave and the third square wave respectively; wherein the duty cycle of the second square wave and the third square wave is the same as that of the first square wave, and the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively; control all single-phase input modules 120 and three-phase output modules 150 to correspond one-to-one and conduct simultaneously, so as to provide three-phase output through the three-phase output module 150.

[0027] When the energy storage system is operating, if the control module 130 receives an external command confirming that the energy storage system needs to perform single-phase to three-phase connection, the control module 130 will first determine the power supply input of the three single-phase input modules 120. Because the entire grid connection process relies on the power input of the three single-phase input modules 120, the grid connection operation can only proceed normally when all three single-phase input modules 120 have power supply input. When the control module 130 can determine that all three single-phase input modules 120 have power supply input, it can select one single-phase input module 120 as the first input module and start outputting a first square wave to control that single-phase input module 120 at the first time point.

[0028] After setting one single-phase input module 120 as the first input module, the control module 130 selects one of the remaining two single-phase input modules 120 as the second input module. Starting at a second time point after the first time point, it outputs a second square wave to control this second input module. The last remaining module is used as the third input module, and a third square wave is output at a third time point after the first time point to control this third input module. The first, second, and third square waves have the same duty cycle. By controlling the relationship between the first, second, and third time points, the phase difference between each pair of the first, second, and third square waves is made 120 degrees, thus approximating a three-phase power input. In one embodiment, the second time point can be set to approximately 6.67 ms after the first time point, and the third time point can be set to approximately 13.33 ms after the first time point.

[0029] In one embodiment, the amplitudes of the first square wave, the second square wave, and the third square wave are substantially the same. That is, in order to ensure that the three-phase output power output by the three-phase output module 150 is in a stable state, the amplitudes of the first square wave, the second square wave, and the third square wave need to be set to be substantially the same.

[0030] In one embodiment, such as Figure 3 As shown, the energy storage system also includes a three-phase input module 110 connected to the three-phase power grid input; the control module 130 is further configured to: acquire the phase voltage of any phase in the three-phase power grid, so as to obtain a first time point based on the phase voltage of the phase. Specifically, in the energy storage system, when the control module 130 determines the three-phase power grid input of the three-phase input module 110 in the energy storage system, it considers that the three-phase input module 110 can provide power to the three-phase output module 150 as needed. At this time, in order to ensure that the output power of the three-phase output module 150 does not become abnormal when the three single-phase input modules 120 are connected to the grid, the control module 130 selects one phase of the three-phase power grid input as the reference phase, sets the first input module of the three single-phase input modules 120 to be phase-aligned with the reference phase, that is, monitors the phase voltage of one phase in the three-phase power grid, and obtains the first time point based on the phase voltage of that phase.

[0031] In one embodiment, the control module 130 is further configured to: monitor the power supply status of the single-phase input modules 120, and control all single-phase input modules 120 and the three-phase output module 150 to shut down when the power supply input of any single-phase input module 120 is abnormal. Specifically, in order to ensure that the three-phase output module 150 can provide normal three-phase output, during the operation of the three-phase output module 150, the control module 130 will continuously monitor the power supply status of each single-phase input module 120. When any one or more single-phase input modules 120 experience a power supply input abnormality, the control module 130 will control all single-phase input modules 120 to shut down the three-phase output module 150, thereby ultimately shutting down the output of the three-phase output module 150 and preventing output imbalance that could lead to abnormal downstream loads.

[0032] like Figure 6 As shown, in one specific embodiment, the control module 130 sets the switching module 140 according to the corresponding control command, so that the three phases of the three-phase output module 150 are connected to the positive terminals of the three single-phase input modules 120 one by one, so that the single-phase input modules 120 supply power to the three-phase output module 150, and then supply power to external devices through the single-phase output module 160. The neutral wire of the three-phase output module 150 is connected to the negative terminals of the three single-phase input modules 120.

[0033] Based on embodiments of the present invention, it is possible to combine independent single-phase energy storage systems into a distributed three-phase energy storage system. Without sacrificing portability, only three single-phase energy storage devices are needed to form a distributed three-phase energy storage system, and the cost is far lower than that of traditional three-phase energy storage systems.

[0034] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A power output control method for an energy storage system, characterized in that, in, The energy storage system includes: three single-phase input modules for connecting to the single-phase energy storage system, and a three-phase output module for providing three-phase output; the method includes: When all the single-phase input modules have power input, a first square wave is generated at a first time point to control the power output of one of the single-phase input modules through the first square wave; A second square wave is generated at a second time point after the first time point, and a third square wave is generated at a third time point after the first time point, so as to control the power output of the remaining two single-phase input modules respectively through the second square wave and the third square wave; wherein, the second square wave and the third square wave have the same duty cycle as the first square wave, and the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively. All the single-phase input modules are controlled to correspond one-to-one with the three-phase output modules and be turned on simultaneously, so as to provide three-phase output through the three-phase output modules.

2. The power output control method for an energy storage system according to claim 1, characterized in that, The energy storage system further includes a three-phase input module connected to the three-phase power grid input, and the method further includes: The phase voltage of any phase in the three-phase power grid is obtained, so as to obtain the first time point based on the phase voltage of the phase.

3. The power output control method for an energy storage system according to claim 2, characterized in that, The step of obtaining the phase voltage of any phase in the three-phase power grid, and obtaining the first time point based on the phase voltage of the phase, includes: The phase voltage amplitude of the phase is monitored, and the time point corresponding to when the phase voltage amplitude of the phase is a preset value is taken as the first time point.

4. The power output control method for an energy storage system according to claim 3, characterized in that, The preset value ranges from 176 to 264V.

5. The power output control method for an energy storage system according to claim 1, characterized in that, The method further includes: Monitor the power supply status of the single-phase input modules, and when the power supply input of any single-phase input module is abnormal, control all single-phase input modules and the three-phase output modules to be turned off.

6. The power output control method for an energy storage system according to claim 1, characterized in that, The amplitudes of the first square wave, the second square wave, and the third square wave are basically the same.

7. The power output control method for an energy storage system according to claim 1, characterized in that, The duty cycles of the first square wave, the second square wave, and the third square wave are all 50%.

8. An energy storage system, characterized in that, include: Three single-phase input modules for connecting a single-phase energy storage system, a three-phase output module for providing three-phase output; and a control module, the control module being used for: When all the single-phase input modules have power input, a first square wave is generated at a first time point to control the power output of one of the single-phase input modules through the first square wave; A second square wave is generated at a second time point after the first time point, and a third square wave is generated at a third time point after the first time point, so as to control the power output of the remaining two single-phase input modules respectively through the second square wave and the third square wave; wherein, the second square wave and the third square wave have the same duty cycle as the first square wave, and the phase difference between the second square wave and the third square wave and the first square wave is 120 degrees and 240 degrees respectively. All the single-phase input modules are controlled to correspond one-to-one with the three-phase output modules and be turned on simultaneously, so as to provide three-phase output through the three-phase output modules.

9. The energy storage system according to claim 8, characterized in that, The energy storage system also includes a three-phase input module connected to the three-phase power grid input; the control module is further used for: The phase voltage of any phase in the three-phase power grid is obtained, so as to obtain the first time point based on the phase voltage of the phase.

10. The energy storage system according to claim 8, characterized in that, The control module is also used for: Monitor the power supply status of the single-phase input modules, and when the power supply input of any single-phase input module is abnormal, control all single-phase input modules and the three-phase output modules to be turned off.

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