Control method of power supply circuit, power supply device and energy storage device

Abstract

The application provides a control method of a power supply circuit, a power supply device and an energy storage device. The power supply circuit comprises a DC / DC conversion unit, a first end of the DC / DC conversion unit is used for connecting a battery pack, a second end of the DC / DC conversion unit is used for connecting a DC bus, and the DC bus is also used for connecting an output end of a DC power generation device. The control method comprises the following steps: in each operation cycle, an actual power generation power of the DC power generation device is obtained; the actual power generation power is subjected to filtering processing to obtain a power filtering value, and a charging power limit value is determined according to the power filtering value; a given charging power of the DC / DC conversion unit is obtained; a target charging power of the DC / DC conversion unit is determined according to the charging power limit value and the given charging power; and the DC / DC conversion unit is controlled to obtain electric energy from the DC bus to charge the battery pack according to the target charging power. The control method of the power supply circuit provided by the application can maintain the charging power of the DC / DC conversion unit in a relatively stable state, and reduce the coupling influence on an inverter.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to a control method for a power supply circuit, a power supply device, and an energy storage device. Background Technology

[0002] With the increasing severity of climate change, clean energy power generation systems that can reduce carbon emissions (such as photovoltaic power generation systems, hydropower generation systems, and wind power generation systems) are attracting more and more attention. Clean energy power generation technology is a technology that converts clean energy into electrical energy to power loads. Related technologies often combine energy storage devices during power generation to achieve efficient utilization of clean energy. For example, in a photovoltaic power generation system, the battery pack can be connected to the same DC bus as the photovoltaic modules and the inverter input terminal via a power supply circuit. In this way, if the power generated by the photovoltaic modules exceeds the power supplied to the inverter-side load, the excess electrical energy can be transferred to the battery pack through the power supply circuit to charge the battery pack.

[0003] However, photovoltaic modules are easily affected by the external environment, which causes the power generation of the photovoltaic modules to fluctuate. This in turn causes the actual charging power of the power supply circuit to fluctuate, thus affecting the maximum power point tracking (MPPT) of the inverter. This further aggravates the fluctuation of the actual power generation of the photovoltaic modules, forming a vicious cycle, until the photovoltaic voltage of the photovoltaic modules fluctuates drastically, or even causes the system to be unable to charge stably and shut down. Summary of the Invention

[0004] In view of this, this application provides a control method for a power supply circuit, a power supply device, and an energy storage device, which can realize the stable operation of the power supply system when the battery pack is in a charging state.

[0005] The first aspect of this application provides a control method for a power supply circuit. The power supply circuit includes a DC / DC conversion unit, a first terminal of which is connected to a battery pack, and a second terminal of which is connected to a DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device. The control method includes: in each operating cycle, acquiring the actual power output of the DC power generation device; filtering the actual power output to obtain a power filter value, and determining a charging power limit based on the power filter value; acquiring a given charging power for the DC / DC conversion unit; determining a target charging power for the DC / DC conversion unit based on the charging power limit and the given charging power; and controlling the DC / DC conversion unit to draw power from the DC bus to charge the battery pack according to the target charging power.

[0006] In one embodiment, filtering the actual generated power to obtain a power filter value and determining a charging power limit based on the power filter value includes: performing a first filtering process on the actual generated power to obtain a first power filter value and determining a first charging power limit based on the first power filter value; performing a second filtering process on the actual generated power to obtain a second power filter value and determining a second charging power limit based on the second power filter value; the response speed of the second filtering process is slower than that of the first filtering process; correspondingly, determining the target charging power of the DC / DC conversion unit based on the charging power limit and a given charging power includes: determining the target charging power of the DC / DC conversion unit based on the first charging power limit, the second charging power limit, and the given charging power.

[0007] In one embodiment, determining the target charging power of the DC / DC conversion unit based on a first charging power limit, a second charging power limit, and a given charging power includes: determining the minimum value among the first charging power limit, the second charging power limit, and the given charging power; and using the minimum value as the target charging power.

[0008] In one embodiment, the actual power generation is subjected to a first filtering process to obtain a first power filtering value, and a first charging power limit is determined based on the first power filtering value, including: performing a first filtering process on the actual power generation to obtain a first power filtering value; and determining the difference between the first power filtering value and a first reserved power value as the first charging power limit.

[0009] In one embodiment, the actual power generation is subjected to a second filtering process to obtain a second power filtering value, and a second charging power limit is determined based on the second power filtering value. This includes: performing a second filtering process on the actual power generation to obtain a second power filtering value; determining the difference between the second power filtering value and a second reserved power value as the second charging power limit, wherein the second reserved power value is greater than the first reserved power value.

[0010] In one embodiment, when there are multiple DC / DC conversion units, obtaining the given charging power of the DC / DC conversion unit includes: determining the total target charging power based on the actual grid-connected power and the target grid-connected power; obtaining the allocation parameters corresponding to each DC / DC conversion unit; and determining the given charging power corresponding to each DC / DC conversion unit based on the total target charging power and the allocation parameters.

[0011] In one embodiment, before controlling the DC / DC conversion unit to draw power from the DC bus to charge the battery pack according to the target charging power, the method further includes: limiting the target charging power to be less than or equal to the rated maximum charging power of the DC / DC conversion unit.

[0012] A second aspect of this application provides a power supply device, which includes a power supply circuit and a controller. The power supply circuit includes a DC / DC conversion unit, a first terminal of which is used to connect to a battery pack, and a second terminal of which is used to connect to a DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device. The controller is used to execute the control method of the power supply circuit as described in any of the preceding claims.

[0013] In one embodiment, the DC / DC conversion unit includes a first DC / DC conversion unit and a second DC / DC conversion unit. A first terminal of both the first and second DC / DC conversion units is used to connect to a battery pack. A second terminal of the first DC / DC conversion unit is used to connect to a first DC bus, and a second terminal of the second DC / DC conversion unit is used to connect to a second DC bus. The first and second DC buses are configured within a power supply device. The power supply device also includes a first DC input terminal, a second DC input terminal, a first DC output terminal, and a second DC output terminal. Specifically: the first DC input terminal and the first DC output terminal are both connected to the first DC bus; the first DC input terminal is used to connect to a first DC power generation device, and the first DC output terminal is used to connect to a first input terminal of an inverter; the second DC input terminal and the second DC output terminal are both connected to the second DC bus; the second DC input terminal is used to connect to a second DC power generation device, and the second DC output terminal is used to connect to a second input terminal of an inverter.

[0014] A third aspect of this application provides an energy storage device, which includes a power supply circuit, a battery pack, and a controller. The power supply circuit includes a DC / DC conversion unit, a first terminal of which is connected to the battery pack, and a second terminal of which is connected to a corresponding DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device. The controller is used to execute the control method of the power supply circuit as described in any of the preceding claims.

[0015] The power supply circuit control method provided in this application first filters the actual power output of the DC power generation equipment to obtain a power filter value after eliminating jitter in the actual power output; then, it determines a charging power limit based on the power filter value, and determines the target charging power of the DC / DC conversion unit based on the given charging power of the DC / DC conversion unit and the charging power limit. Thus, the target charging power determined based on the power filter value after eliminating jitter can reduce the impact of actual power output jitter on the charging power of the DC / DC conversion unit, thereby reducing the coupling effect on the inverter, maintaining a stable charging operation state of the power supply system, and effectively solving the problem of easy power supply system shutdown when the actual power output of the DC power generation equipment suddenly drops. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be considered as a limitation on the scope of protection of this application. In the various drawings, similar components are numbered similarly.

[0017] Figure 1 This is a schematic diagram of a power supply system provided in an embodiment of this application.

[0018] Figure 2 This is a flowchart illustrating a control method for a power supply circuit provided in an embodiment of this application.

[0019] Figure 3 This is a flowchart illustrating the sub-steps of step S202 provided in an embodiment of this application.

[0020] Figure 4 This is a flowchart illustrating the sub-steps of step S301 provided in an embodiment of this application.

[0021] Figure 5 This is a flowchart illustrating the sub-steps of step S302 provided in an embodiment of this application.

[0022] Figure 6 This is a flowchart illustrating the sub-steps for determining the target charging power of a DC / DC conversion unit based on a first charging power limit, a second charging power limit, and a given charging power, according to an embodiment of this application.

[0023] Figure 7A This is a schematic diagram illustrating the principle of switching between the first filtering process and the second filtering process when the first filtering process is a moving average filtering process and the second filtering process is a low-pass filtering process in one embodiment of this application.

[0024] Figure 7B This is a schematic diagram showing how the power values ​​change with the fluctuation of the actual power generation when the first filtering process is a moving average filtering process and the second filtering process is a low-pass filtering process, according to one embodiment of this application.

[0025] Figure 8 A schematic diagram of a power supply system provided for another embodiment of this application.

[0026] Figure 9 This is a flowchart illustrating the sub-steps of step S203 when there are multiple DC / DC conversion units.

[0027] Figure 10 This is a structural block diagram of a power supply device provided in an embodiment of this application.

[0028] Figure 11 This is a structural block diagram of an energy storage device provided in an embodiment of this application.

[0029] Figure 12 This is a structural block diagram of a control device provided in an embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0031] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," "upper," "lower," "left," "right," "front," "back," and similar expressions used in this article are for illustrative purposes only.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0033] Some embodiments will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] With the increasing severity of climate change, clean energy power generation systems that can reduce carbon emissions (such as photovoltaic power generation systems, hydropower generation systems, and wind power generation systems) are attracting more and more attention. Clean energy power generation technology is a technology that converts clean energy into electrical energy to power loads. Related technologies often incorporate energy storage devices during power generation to achieve efficient utilization of clean energy.

[0035] For example, please see Figure 1 , Figure 1 This is a schematic diagram of a power supply system 10 provided in an embodiment of this application. The power supply system 10 includes a battery pack 110, a power supply circuit 120, a DC power generation device 130, and an inverter 140. The first terminal of the power supply circuit 120 is connected to the battery pack 110, and the second terminal of the power supply circuit 120 is connected to a DC bus (including a positive DC bus DC_BUS+ and a negative DC bus DC_BUS-). The DC bus is also used to connect the output terminal of the DC power generation device 130 and the input terminal of the inverter 140. The output terminal of the inverter 140 is connected to the power grid 20 via an AC bus (including a neutral wire N and a live wire L).

[0036] Furthermore, the battery pack 110 contains one or more cells connected in series and / or parallel. The battery pack 110 is used to store or release energy.

[0037] The power supply circuit 120 includes a DC-DC converter 121. The first terminal of the DC-DC converter 121 is connected to the battery pack 110, and the second terminal is connected to the DC bus DC_BUS+ / DC_BUS-. The DC-DC converter 121 is used to step up or down the battery voltage of the battery pack 110 and discharge it through the DC bus, or to step up or down the charging voltage provided by the DC bus and charge the battery pack 110. When operating in charging mode, the DC-DC converter 121 draws power from the DC generator 130 via the DC bus for power conversion to charge the battery pack 110. When operating in discharging mode, the DC-DC converter 121 converts the electrical energy output from the battery pack 110 into DC power to be output to the inverter 140.

[0038] Understandably, the DC / DC conversion unit 121 can be composed of a BUCK circuit, a BOOST circuit, or a BUCK-BOOST circuit. Thus, by controlling the switching logic and duty cycle of the BUCK circuit, BOOST circuit, or BUCK-BOOST circuit, the DC / DC conversion unit 121 can be controlled to operate in charging or discharging mode, and the output power of the DC / DC conversion unit 121 can be controlled. In other embodiments, the DC / DC conversion unit 121 may include a boost circuit and a DAB (Dual Active Bridge) circuit, or it may include a boost circuit and an LLC series-parallel resonant circuit. The specific circuit structures of the boost circuit, DAB circuit, and LLC circuit are not limited here.

[0039] The DC power generation device 130 can be a clean energy device for outputting DC power, such as a photovoltaic power generation device or a hydrogen power generation device. In other embodiments, the DC power generation device 130 can also be other power generation devices for outputting DC power. In this application, the DC power generation device 130 is described as a photovoltaic power generation device, such as a photovoltaic module. The photovoltaic module includes several photovoltaic panels, which convert light energy into electrical energy to output DC power to the inverter 140 and / or charge the battery pack 110 through the power supply circuit 120. Understandably, this application does not limit the connection method of the photovoltaic panels in the DC power generation device 130. For example, in some embodiments, the photovoltaic panels in the DC power generation device 130 can be connected in series, in parallel, or in series followed by parallel, etc.

[0040] Inverter 140 includes at least a Direct Current to Alternating Current (DC / AC) conversion unit to convert the DC power output from DC power generation device 130 and / or power supply circuit 120 into AC power, and output it to the AC bus to power load 30 and / or feed power to the grid 20. Understandably, this application does not limit the specific circuit structure of the DC / AC conversion unit; for example, the DC / AC conversion unit can be a full-bridge topology, a half-bridge topology, etc. In some embodiments, when DC power generation device 130 is a photovoltaic power generation device, inverter 140 may also include a Maximum Power Point Tracking (MPPT) circuit to achieve maximum power point tracking for the photovoltaic power generation device.

[0041] The power grid 20 can be, for example, a municipal power grid. Understandably, this application does not limit the type of AC power in the power grid 20; in other embodiments, the power grid 20 can be single-phase AC, three-phase AC, or other multi-phase AC, etc. The load 30 can be various electrical loads in a household.

[0042] Understandably, photovoltaic modules are easily affected by the external environment, which causes the power generation of the photovoltaic modules to fluctuate. This in turn causes the actual charging power of the power supply circuit to fluctuate, thus affecting the inverter's maximum power point tracking (MPPT), further aggravating the fluctuation of photovoltaic power, forming a vicious cycle, and eventually even causing the system to be unable to charge stably and shut down.

[0043] Therefore, this application provides a control method for a power supply circuit, which can achieve stable operation of the power supply system when the battery pack is charging. Understandably, this control method for the power supply circuit can be executed by a controller. The control method includes the following steps:

[0044] Step S201: In each operating cycle, obtain the actual power generation of the DC power generation equipment.

[0045] In step S201, the operating cycle can be set according to actual needs. For example, the operating cycle can be the operating cycle of the controller of the control device.

[0046] In some embodiments, the power output of the DC power generation device 130 can be obtained in real time by setting a sensor (e.g., a Hall sensor or other power measurement sensor) at the output of the DC power generation device and communicating with the sensor.

[0047] Step S202: Filter the actual power generation to obtain the power filter value, and determine the charging power limit based on the power filter value.

[0048] Understandably, when the DC power generation device 130 is affected by the environment, the actual power generation of the DC power generation device 130 is prone to fluctuation. For example, when the DC power generation device 130 is a photovoltaic module, when the weather changes in the environment where the photovoltaic module is located, or when the photovoltaic module is blocked by obstructions (such as clouds, leaves, etc.), the actual power generation of the photovoltaic module is prone to fluctuation. Therefore, in step S202, the actual power generation is filtered to obtain a power filter value in order to eliminate the fluctuation in the actual power generation as much as possible.

[0049] The filtering process in step S202 can be based on low-pass filtering, average filtering, median filtering, etc. This application does not limit the filtering algorithm used in step S202.

[0050] Further, the charging power limit in step S202 is used to characterize the maximum charging power of the DC / DC conversion unit 121. In some embodiments, the charging power limit can be determined based on the power filter value and the reserved power value. Understandably, in order to maintain the normal operation of the power supply system 10, it is necessary to maintain the normal operation of the inverter 140 (at least maintain the MPPT function), so a portion of the actual power generated by the DC power generation device 130 is used to power the inverter 140 at least. Thus, the reserved power value can be the minimum power consumption of the inverter 140 when maintaining normal operation. Therefore, the charging power limit can be determined based on the reserved power value and the minimum power consumption of the inverter 140.

[0051] Step S203: Obtain the given charging power of the DC / DC conversion unit.

[0052] In step S203, the given charging power of the DC / DC conversion unit 121 can be calculated based on the actual grid-connected power and the target grid-connected power.

[0053] Understandably, when the output of inverter 140 is connected to the power grid 20 via the AC bus, it is referred to as grid connection. Actual grid-connected power is used to represent the power supply relationship between inverter 140 connected to the AC bus, load 30, and the power grid 20. Furthermore, in this application, the actual grid-connected power can be positive, negative, or zero, depending on the energy flow direction between inverter 140, load 30, and the power grid 20. For example, when inverter 140 outputs 10W to grid 20 through the AC bus, the actual grid-connected power between inverter 140, load 30, and grid 20 is 10W; when grid 20 outputs 10W to the AC bus to supply power to load 30, the actual grid-connected power between inverter 140, load 30, and grid 20 is -10W; when the output power of inverter 140 just meets the power demand of load 30, that is, when inverter 140 neither outputs power to grid 20 nor grid 20 outputs power to load 30, the actual grid-connected power is 0.

[0054] The target grid-connected power is used to characterize the ideal value of the grid-connected power between the AC bus and the grid 20. Thus, when the actual grid-connected power is greater than the target grid-connected power, it indicates that the inverter 140 is outputting excess energy to the grid 20. At this time, the battery pack 110 can be charged by controlling the DC / DC conversion unit 121 to reduce the output power of the inverter 140, thereby bringing the actual grid-connected power closer to the target grid-connected power and achieving maximum self-consumption.

[0055] It is understood that the definitions of positive and negative grid-connected power in this application are merely exemplary. In other embodiments, when the actual grid-connected power is positive, it may also indicate that the grid is supplying power to the load, and when the actual grid-connected power is negative, it may indicate that the inverter 140 is selling electricity to the grid.

[0056] Thus, based on a preset closed-loop feedback algorithm, the given charging power of the DC / DC conversion unit can be calculated according to the deviation between the actual grid-connected power and the target grid-connected power.

[0057] Understandably, the closed-loop feedback algorithm can use PI (proportional-integral control), PID (proportional-integral-derivative control), or other control algorithms.

[0058] In some embodiments, a grid monitoring module (not shown in the figure) can be installed between the local microgrid system consisting of the power supply system 10 and the load 30 and the power grid 20, that is, between the common connection point of the inverter 140 output terminal and the load 30 and the power grid 20. The grid monitoring module is used to monitor the grid connection parameters between the AC bus and the power grid 20. The grid connection parameters may include grid connection current, grid connection voltage, and actual grid connection power. In this way, the controller can obtain the actual grid connection power output from the inverter 140 to the power grid 20, or from the power grid 20 to the load 30, by communicating with the grid monitoring module. In some embodiments, the grid monitoring module can be a smart meter, and the smart meter can transmit the actual grid connection power to the controller.

[0059] Step S204: Determine the target charging power of the DC / DC conversion unit based on the charging power limit and the given charging power.

[0060] Understandably, since the charging power limit characterizes the maximum charging power of the DC / DC conversion unit 121, the actual charging power of the DC / DC conversion unit 121 is always less than or equal to the charging power limit.

[0061] In other words, when the given charging power is less than or equal to the charging power limit, the given charging power can be used as the target charging power of the DC / DC conversion unit 121, so that when the DC / DC conversion unit 121 charges the battery pack 110 according to the target charging power, the actual grid-connected power is close to the target grid-connected power. When the given charging power is greater than the charging power limit, the target charging power of the DC / DC conversion unit 121 can be determined based on the given charging power and the charging power limit according to the preset charging power calculation rules, and the target charging power is less than the charging power limit. In this way, since the target charging power is obtained based on the power filter value after filtering, the impact of actual power generation fluctuations on the charging power of the DC / DC conversion unit 121 can be reduced.

[0062] Understandably, since the charging power limit characterizes the maximum charging power of the DC / DC conversion unit 121 when the inverter 140 maintains the MPPT function, the target charging power determined in step S204 ensures that the inverter 140 maintains the MPPT function.

[0063] Step S205: Control the DC / DC conversion unit to obtain power from the DC bus to charge the battery pack according to the target charging power.

[0064] In step S205, the DC / DC conversion unit 121 obtains the electrical energy output by the DC power generation device 130 from the DC bus according to the target charging power, performs power conversion, and charges the battery pack 110 through the first terminal, wherein the charging power of the first terminal is the target charging power.

[0065] Thus, the controller executes steps S201 to S205 in each cycle to update the target charging power of the DC / DC conversion unit 121 in each cycle based on the power filter value obtained after filtering. This reduces the fluctuation of the charging power of the DC / DC conversion unit 121 caused by the fluctuation of the actual power generation of the DC power generation device 130, thereby reducing the impact on the inverter 140 and enabling the power supply system 10 to maintain a stable charging operation state even when the actual power generation of the DC power generation device 130 fluctuates.

[0066] In summary, the power supply circuit control method provided in this application first filters the actual power output of the DC power generation device to obtain a power filter value after eliminating jitter in the actual power output; then, it determines the charging power limit based on the power filter value, and determines the target charging power of the DC / DC conversion unit 121 based on the given charging power of the DC / DC conversion unit and the charging power limit. In this way, the target charging power determined based on the power filter value after eliminating jitter can reduce the impact of actual power output jitter on the charging power of the DC / DC conversion unit 121, keep the charging power of the DC / DC conversion unit 121 in a relatively stable state, maintain the stable charging operation state of the power supply system 10, and effectively solve the problem that the power supply system 10 is prone to shutdown when the actual power output of the DC power generation device 130 suddenly drops.

[0067] Please continue reading. Figure 3 In some embodiments, step S202 includes the following sub-steps:

[0068] Step S301: Perform a first filtering process on the actual power generation to obtain a first power filtering value, and determine a first charging power limit based on the first power filtering value.

[0069] Step S302: Perform a second filtering process on the actual power generation to obtain a second power filtering value, and determine the second charging power limit based on the second power filtering value.

[0070] The response speed of the second filtering process is slower than that of the first filtering process. Similarly, the first charging power limit is used to characterize the maximum charging power of the DC / DC conversion unit 121 after the actual generated power is subjected to the first filtering process; the second charging power limit is used to characterize the maximum charging power of the DC / DC conversion unit 121 after the actual generated power is subjected to the second filtering process.

[0071] The slower response speed of the second filtering process compared to the first refers to the longer delay time of the filtering algorithm used in the second process compared to the first. Understandably, when the input signal undergoes a sudden change, the filter's output signal does not immediately follow the change in the input signal, but gradually approaches the change with a certain delay. Because the second filtering process has a slower response speed than the first, when the actual power generation fluctuation is large, the first power filter value can better follow the change in actual power generation; when the actual power generation fluctuation is small, the second power filter value is more stable than the first. In other words, the first and second filtering processes each have their respective advantages corresponding to different degrees of fluctuation in actual power generation.

[0072] Understandably, the first and second filtering processes can be implemented in software or hardware, and can be set according to actual needs. This application does not impose any restrictions on this.

[0073] Accordingly, the target charging power of the DC / DC conversion unit is determined based on the charging power limit and the given charging power, including:

[0074] The target charging power of the DC / DC conversion unit is determined based on the first charging power limit, the second charging power limit, and the given charging power.

[0075] In some embodiments, the target charging power of the DC / DC conversion unit 121 can be determined based on a preset charging power calculation rule, according to the first charging power limit, the second charging power limit, and the given charging power. This is to achieve the purpose of switching different filtering processes according to the degree of change in the actual power generation, thereby reducing the fluctuation of the charging power of the DC / DC conversion unit 121, thereby reducing the coupling effect on the inverter 140, and finally achieving stable operation of the inverter 140 when the battery pack 110 is in the charging state.

[0076] For example, in some embodiments, the preset charging power calculation rule may include: when the given charging power is less than a first charging power limit and less than a second charging power limit, the given charging power is taken as the target charging power of the DC / DC conversion unit 121.

[0077] In some embodiments, the preset charging power calculation rule may further include: when the given charging power is greater than the first charging power limit or the second charging power limit, the first charging power limit or the second charging power limit is determined as the target charging power of the DC / DC conversion unit 121 based on the degree of change in the actual power generation.

[0078] Specifically, when the given charging power is greater than the first charging power limit or the second charging power limit, the difference between the actual power generation of the current operating cycle and the actual power generation of the previous operating cycle can be calculated. Then, the difference is divided by the actual power generation of the previous operating cycle to obtain a ratio. When the ratio is greater than or equal to the first preset threshold, the first charging power limit is used as the target charging power of the DC / DC conversion unit 121. When the ratio is less than the first preset threshold, the second charging power limit is used as the target charging power of the DC / DC conversion unit 121.

[0079] This application does not limit the preset charging calculation rules. In other embodiments, the preset charging calculation rules may also be preset calculation formulas.

[0080] In summary, by performing a first filtering process on the actual power output of the DC power generation device 130 to obtain a first power filter value, the first power filter value, which has a small delay and fast response speed, can better reflect the changes in the actual power output while eliminating fluctuations in the actual power output. By performing a second filtering process on the actual power output to obtain a second power filter value, the second power filter value, which has a high delay and slow response speed, can eliminate fluctuations in the actual power output while obtaining a more stable second power filter value. Furthermore, a first charging power limit is determined based on the first power filter value, a second charging power limit is determined based on the second power filter value, and a target charging power for the DC / DC conversion unit 121 is determined based on the first charging power limit, the second charging power limit, and a given charging power. This allows for a smooth transition between the first and second filtering processes when fluctuations in the actual power output occur, minimizing the impact of the actual power output on the charging power of the DC / DC conversion unit 121, thereby reducing the coupling effect on the input of the inverter 140 and achieving stable operation of the power supply system when the battery pack 110 is in a charging state.

[0081] Understandably, in other embodiments, the actual power generation may be subjected to three or more filtering processes to obtain multiple charging power limits, wherein each filtering process has a different response speed. Thus, the target charging power of the DC / DC conversion unit 121 can be determined based on multiple different charging power limits and a given charging power.

[0082] Please continue reading. Figure 4 In some embodiments, step S301 includes:

[0083] Step S401: Perform a first filtering process on the actual power generation to obtain the first power filtering value.

[0084] In some embodiments, the first filtering process can be based on a moving average filtering algorithm. Understandingly, moving average filtering is also called moving window average filtering. The basic principle of the moving average filtering algorithm is to sequentially sample N input data. If there are fewer than N input data points, the average of all current input data is output; if there are more than N input data points, the output is equal to the average of the next N sampled input data points. The moving average filtering algorithm can effectively eliminate periodic interference and some irregular interference. The moving average filtering algorithm has low latency and fast response speed.

[0085] This application does not impose any restrictions on the parameters (e.g., the specific value of N) in the moving average filtering algorithm used.

[0086] Step S402: Determine the difference between the first power filter value and the first reserved power value as the first charging power limit.

[0087] The first reserved power value can be the minimum power consumption value used to maintain the MPPT function of the inverter 140, and the specific value can be set according to actual needs.

[0088] Please continue reading. Figure 5 In some embodiments, step S302 includes:

[0089] Step S501: Perform a second filtering process on the actual power generation to obtain the second power filtering value.

[0090] In some embodiments, the second filtering process can be based on a low-pass filtering algorithm. Understandably, a low-pass filtering algorithm can be used to filter out high-frequency components in actual generated power. Compared to a moving average filtering algorithm, the low-pass filtering algorithm has a higher delay and slower response speed, but better stability. The low-pass filtering algorithm can be calculated based on the following formula:

[0091] Y(n) = aX(n) + (1-a)Y(n-1)

[0092] Where 'a' is the filter coefficient, X(n) is the current sampled value, Y(n-1) is the second power filter value obtained from the low-pass filter algorithm in the previous running cycle, and Y(n) is the second power filter value obtained from the low-pass filter algorithm in the current running cycle. This application does not impose any restrictions on the filter coefficient.

[0093] Understandably, low-pass filtering can be implemented in software or hardware, depending on the specific requirements. For example, in one example, a first-order low-pass filter circuit consisting of a capacitor and a resistor can achieve the filtering function.

[0094] Step S502: The difference between the second power filter value and the second reserved power value is determined as the second charging power limit, and the second reserved power value is greater than the first reserved power value.

[0095] Understandably, since the second reserved power value is greater than the first reserved power value, the second reserved power value is also sufficient to enable the inverter 140 to maintain MPPT function.

[0096] Furthermore, although the response speeds of the first and second filtering processes differ, when the fluctuation range of the actual power generation is small, the first power filter value obtained after the first filtering process and the second power filter value obtained after the second filtering process will be relatively close. Since the second reserved power value is greater than the first reserved power value, the second charging power limit is more likely to be less than the first charging power limit. When the fluctuation range of the actual power generation is large, such as a sudden and significant drop, the response speed of the second filtering process is slower than that of the first filtering process. Therefore, the first power filter value obtained after the first filtering process is more likely to be smaller than the second power filter value. In this case, even if the second reserved power value is greater than the first reserved power value, the faster response speed of the first filtering process still makes it more likely that the first charging power limit will be less than the second charging power limit. Thus, configuring the second reserved power value to be greater than the first reserved power value in step S502 allows the relationship between the first and second charging power limits to change according to the fluctuation range of the actual power generation.

[0097] Please continue reading. Figure 6 In some embodiments, determining the target charging power of the DC / DC conversion unit based on a first charging power limit, a second charging power limit, and a given charging power includes:

[0098] Step S601: Determine the minimum value among the first charging power limit, the second charging power limit, and the given charging power.

[0099] Step S602: Use the minimum value as the target charging power.

[0100] Understandably, when the given charging power is less than the first charging power limit and less than the second charging power limit, the given charging power is taken as the target charging power. When the DC / DC conversion unit 121 charges the battery pack 110 according to the target charging power, the actual grid-connected power is close to the target grid-connected power.

[0101] When the given charging power exceeds the first charging power limit and / or the second charging power limit, the minimum of the first charging power limit and the second charging power limit is used as the target power. Thus, based on the setting that the second reserved power value is greater than the first reserved power value as described in the above embodiment, the controller can switch between the first filtering process and the second filtering process according to the fluctuation range of the actual generated power, so as to maximize the stability of the filtered power value obtained after filtering, thereby ensuring that the power flowing to the input terminal of the inverter 140 also remains stable, reducing the impact of the actual generated power fluctuation of the DC power generation device 130 on the inverter 140.

[0102] For example, please see Figure 7A , Figure 7A This is a schematic diagram illustrating the switching principle between the first and second filtering processes when the first filtering process is a moving average filtering process and the second filtering process is a low-pass filtering process. Figure 7A Curve P71 represents the change of actual power generation over time; curve P72 represents the change of the first power filter value over time; curve P73 represents the change of the second power filter value over time; curve P74 represents the change of the first charging power limit over time; curve P75 represents the change of the second charging power limit over time; and curve P76 represents the change of the target charging power over time.

[0103] from Figure 7A It can be seen that during the time period t0-t1, the DC power generation equipment is in a relatively stable state, and the low-pass filter is in effect, meaning the second charging power limit is used as the target charging power. At time t1, the actual power generation suddenly drops, the moving average filter is in effect, and the first charging power limit is less than the second charging power limit, so the first charging power limit is used as the target charging power. During the time period t1-t2, since the first charging power limit is less than the second charging power limit, the first charging power limit is used as the target charging power. At time t2, the first charging power limit and the second charging power limit are the same, and the fast and slow loops switch at this moment. During the time period t2-t3, the second charging power limit is less than the first charging power limit, so the second charging power limit is used as the target charging power. During the time period t3-t4, the system is in a stable state, and the second charging power limit continues to be used as the target charging power.

[0104] Please continue reading. Figure 7B , Figure 7BThis is a schematic diagram showing the changes in various power values ​​as the actual power generation fluctuates, when the first filtering process is a moving average filtering process and the second filtering process is a low-pass filtering process, according to one embodiment of this application. Curve P77 represents the actual power generation over time; curve P78 represents the first power filter value over time; curve P79 represents the second power filter value over time; curve P80 represents the target charging power over time; and curve P81 represents the voltage of the DC power generation device over time.

[0105] from Figure 7B As can be seen, the power supply circuit control method provided in this application can determine the target charging power of the DC / DC conversion unit 121 based on the second power filter value obtained by the second filtering process when the actual power generation fluctuates slightly, so as to keep the charging power of the DC / DC conversion unit 121 and the photovoltaic voltage of the DC power generation device 130 stable; it can also quickly switch from the second filtering process to the first filtering process when the actual power generation suddenly drops, so as to determine the target charging power of the DC / DC conversion unit 121 based on the first power filter value obtained by the first filtering process, so as to immediately reduce the charging power and effectively prevent the photovoltaic voltage from being pulled down.

[0106] In some embodiments, the DC / DC conversion unit 121 may include multiple sub-units. For example, see [link to relevant documentation]. Figure 8 In some embodiments, the DC / DC conversion unit 121 includes a first DC / DC conversion unit 1211 and a second DC / DC conversion unit 1212. Correspondingly, the inverter 140 is an inverter configured with multiple input channels. For example... Figure 8 As shown, the inverter 140 includes a first input terminal INV_IN1+ / INV_IN1- and a second input terminal INV_IN2+ / INV_IN2-. The first DC / DC conversion unit 1211 and the second DC / DC conversion unit 1212 can be connected to different DC power generation devices 130, respectively. In other embodiments, multiple single-input channel inverters can also be connected in parallel. Understandably, this application does not limit the number of DC / DC conversion units 121 in the power supply circuit 120.

[0107] Please see Figure 9 When there are multiple DC / DC conversion units, step S203 includes:

[0108] Step S901: Determine the total target charging power based on the actual grid-connected power and the target grid-connected power.

[0109] Understandably, the difference between the actual grid-connected power and the target grid-connected power can be used as the total target charging power.

[0110] Step S902: Obtain the allocation parameters corresponding to each DC / DC conversion unit.

[0111] In step S902, the allocation parameters are used to characterize the proportion of the given charging power of the corresponding DC / DC conversion unit in the total target charging power. In some embodiments, the allocation parameters are related to the circuit parameters of the corresponding DC / DC conversion unit (e.g., power loss, rated output voltage, rated output current, etc.) and the rated maximum input power of the input terminal of the corresponding connected inverter. The allocation parameters of each DC / DC conversion unit may be equal or unequal, and this application does not impose any limitation on this.

[0112] Step S903: Determine the given charging power for each DC / DC conversion unit based on the total target charging power and allocation parameters.

[0113] In some embodiments, the product of the allocation parameters of the corresponding DC / DC conversion unit and the total target charging power can be used as the given charging power of the DC / DC conversion unit.

[0114] In other embodiments, other adjustment parameters may be further incorporated to determine the given charging power of each DC / DC conversion unit based on the allocation coefficient and the total target discharge power. This application does not limit the specific calculation process for determining the first initial discharge power and the second initial discharge power.

[0115] In some embodiments, before controlling the DC / DC conversion unit to obtain electrical energy from the DC bus to charge the battery pack according to the target charging power, the control method of the power supply circuit further includes:

[0116] The target charging power is limited to be less than or equal to the rated maximum charging power of the DC / DC conversion unit.

[0117] Understandably, when the charging power of the DC / DC converter exceeds the rated maximum charging power, some of the electrons in the DC / DC converter may be damaged due to excessive power, thus posing a safety risk. Therefore, in this embodiment, by limiting the target charging power to be less than or equal to the rated maximum charging power of the DC / DC converter, the charging safety of the DC / DC converter can be ensured.

[0118] Please see Figure 10This application also provides a power supply device 100, including a power supply circuit 120 and a controller 150. The power supply circuit 120 includes a DC / DC conversion unit 121. A first terminal of the DC / DC conversion unit 121 is connected to a battery pack 110, and a second terminal of the DC / DC conversion unit 121 is connected to a DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device 130. The controller is used to execute the control method of the power supply circuit as described in any of the above embodiments.

[0119] In some embodiments, the DC / DC conversion unit 121 includes a first DC / DC conversion unit 1211 and a second DC / DC conversion unit 1212. A first terminal of both the first DC / DC conversion unit 1211 and the first terminal of the second DC / DC conversion unit 1212 are used to connect to the battery pack 110. Figure 10 (Not shown), the second terminal of the first DC / DC conversion unit 1211 is used to connect to the first DC bus BUS1+ / BUS1-, and the second terminal of the second DC / DC conversion unit 1212 is used to connect to the second DC bus BUS2+ / BUS2-. The first DC bus BUS1+ / BUS1- and the second DC bus BUS2+ / BUS2- are configured within the power supply equipment 100. The power supply equipment 100 also includes a first DC input terminal IN1+ / IN1-, a second DC input terminal IN2+ / IN2-, a first DC output terminal OUT1+ / OUT1-, and a second DC output terminal OUT2+ / OUT2-, wherein:

[0120] The first DC input terminal IN1+ / IN1- and the first DC output terminal OUT1+ / OUT1- are both connected to the first DC bus BUS1+ / BUS1-. The first DC input terminal IN1+ / IN1- is used to connect to the first DC power generation equipment, and the first DC output terminal OUT1+ / OUT1- is used to connect to the first input terminal of the inverter.

[0121] The second DC input terminal IN2+ / IN2- and the second DC output terminal OUT2+ / OUT2- are both connected to the second DC bus. The second DC input terminal IN2+ / IN2- is used to connect to the second DC power generation equipment, and the second DC output terminal OUT2+ / OUT2- is used to connect to the second input terminal of the inverter.

[0122] Understandably, in other embodiments, the first DC bus BUS1+ / BUS1- and the second DC bus BUS2+ / BUS2- may also be configured by other electronic devices connected to the power supply equipment 100, such as by an inverter.

[0123] Please see Figure 11This application also provides an energy storage device 200. The energy storage device 200 includes a power supply circuit 120, a battery pack 110, and a controller 150. The power supply circuit 120 includes a DC / DC conversion unit 121. A first terminal of the DC / DC conversion unit 121 is connected to the battery pack 110, and a second terminal of the DC / DC conversion unit 121 is connected to a corresponding DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device. The controller 150 is used to execute the control method of the power supply circuit described in any of the above embodiments.

[0124] Understandably, in some embodiments, the first DC bus BUS1+ / BUS1- and the second DC bus BUS2+ / BUS2- may also be located in the energy storage device 200. In other embodiments, the first DC bus BUS1+ / BUS1- and the second DC bus BUS2+ / BUS2- may also be configured by other electronic devices connected to the energy storage device 200, such as an inverter.

[0125] Understandably, the energy storage device 200 can be various electronic devices equipped with a battery pack 110, such as mobile energy storage devices, home energy storage devices, portable air conditioners, portable refrigerators, etc. This application does not limit the specific functions of the energy storage device 200.

[0126] Understandably, the controller 150 is equipped with an Energy Management System (EMS), which executes the control method for the power supply circuit provided in this application, thereby achieving unified control of the energy storage device. The controller 150 can be a processor independent of the battery pack 110 and the power supply circuit 120, or it can be a processor simultaneously equipped with a Battery Management System (BMS) for controlling the battery pack 110. This application does not limit the specific form of the controller.

[0127] In some embodiments, the controller 150 can communicate with the battery pack 110 via a CAN bus, and with the power supply circuit 120 via an RS-485 serial bus. In other embodiments, the controller 150 can also communicate with the battery pack 110 and the power supply circuit 120 via other wired or wireless communication methods, and this application does not limit this.

[0128] One embodiment of this application also provides a control device applied to a power supply circuit 120 or an electronic device integrating a power supply circuit 120. Figure 12 A schematic block diagram of the control device 300 provided in an embodiment of this application is shown. Figure 12 As shown, the control device 300 includes:

[0129] The first acquisition module 310 is used to acquire the actual power generation of the DC power generation equipment in each operating cycle.

[0130] The filtering module 320 is used to filter the actual power generation to obtain the power filter value, and to determine the charging power limit based on the power filter value.

[0131] The second acquisition module 330 is used to acquire the given charging power of the DC / DC conversion unit.

[0132] The determination module 340 is used to determine the target charging power of the DC / DC conversion unit based on the charging power limit and the given charging power.

[0133] The control module 350 is used to control the DC / DC conversion unit to obtain electrical energy from the DC bus to charge the battery pack according to the target charging power.

[0134] The specific details of the control method for implementing the power supply circuit by the control device 300 provided in this application embodiment have been described in detail in the corresponding embodiment of the power supply circuit control method, and will not be repeated here.

[0135] This application also provides a computer-readable medium having a computer program stored thereon, which, when executed by a processor, implements the control method for the power supply circuit as described in the above technical solutions. The computer-readable medium may be a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the program product of this invention is not limited thereto. In this document, the readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, apparatus, or device.

[0136] The above-described program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0137] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting programs for use by or in conjunction with an instruction execution system, apparatus, or device.

[0138] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0139] Program code for performing the operations of this invention can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0140] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0141] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for a power supply circuit, characterized in that, The power supply circuit includes a DC / DC conversion unit. A first terminal of the DC / DC conversion unit is connected to a battery pack, and a second terminal is connected to a DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device and the input terminal of an inverter. The control method includes: In each operating cycle, the actual power generation of the DC power generation equipment is obtained; The actual generated power is filtered to obtain a power filter value, and a charging power limit is determined based on the power filter value and the reserved power value. The reserved power value is the minimum power consumption value for maintaining the MPPT function of the inverter, and the charging power limit is used to characterize the maximum charging power of the DC / DC conversion unit. Obtain the given charging power of the DC / DC conversion unit; The target charging power of the DC / DC conversion unit is determined based on the charging power limit and the given charging power. The DC / DC conversion unit is controlled to obtain electrical energy from the DC bus to charge the battery pack according to the target charging power.

2. The method according to claim 1, characterized in that, The charging power limit includes a first charging power limit and a second charging power limit. The reserved power value includes a first reserved power value and a second reserved power value, wherein the second reserved power value is greater than the first reserved power value. The step of filtering the actual generated power to obtain a power filter value, and determining the charging power limit based on the power filter value and the reserved power value, includes: The actual power generation is subjected to a first filtering process to obtain a first power filtering value, and the first charging power limit is determined based on the first power filtering value and the first reserved power value. The actual power generation is subjected to a second filtering process to obtain a second power filtering value, and the second charging power limit is determined based on the second power filtering value and the second reserved power value; the response speed of the second filtering process is slower than that of the first filtering process. Accordingly, determining the target charging power of the DC / DC conversion unit based on the charging power limit and the given charging power includes: The target charging power of the DC / DC conversion unit is determined based on the first charging power limit, the second charging power limit, and the given charging power.

3. The method according to claim 2, characterized in that, Determining the target charging power of the DC / DC conversion unit based on the first charging power limit, the second charging power limit, and the given charging power includes: Determine the minimum value among the first charging power limit, the second charging power limit, and the given charging power; The minimum value is taken as the target charging power.

4. The method according to claim 2, characterized in that, The step of performing a first filtering process on the actual generated power to obtain a first power filtering value, and determining the first charging power limit based on the first power filtering value and the first reserved power value, includes: The actual generated power is subjected to a first filtering process to obtain a first power filter value; The difference between the first power filter value and the first reserved power value is determined as the first charging power limit.

5. The method according to claim 4, characterized in that, The step of performing a second filtering process on the actual generated power to obtain a second power filtering value, and determining the second charging power limit based on the second power filtering value and the second reserved power value, includes: The actual generated power is subjected to a second filtering process to obtain a second power filter value; The difference between the second power filter value and the second reserved power value is determined as the second charging power limit.

6. The method according to claim 1, characterized in that, When there are multiple DC / DC conversion units, obtaining the given charging power of the DC / DC conversion unit includes: The total target charging power is determined based on the actual grid-connected power and the target grid-connected power. Obtain the allocation parameters corresponding to each DC / DC conversion unit; The given charging power corresponding to each DC / DC conversion unit is determined based on the total target charging power and the allocation parameters.

7. The method according to claim 1, characterized in that, Before controlling the DC / DC conversion unit to draw power from the DC bus to charge the battery pack according to the target charging power, the method further includes: The target charging power is limited to be less than or equal to the rated maximum charging power of the DC / DC conversion unit.

8. A power supply device, characterized in that, The power supply equipment includes a power supply circuit and a controller. The power supply circuit includes a DC / DC conversion unit. A first terminal of the DC / DC conversion unit is used to connect to a battery pack, and a second terminal of the DC / DC conversion unit is used to connect to a DC bus. The DC bus is also used to connect to the output terminal of a DC power generation device and the input terminal of an inverter. The controller is used to execute the control method of the power supply circuit as described in any one of claims 1-7.

9. The power supply equipment as described in claim 8, characterized in that, The DC / DC conversion unit includes a first DC / DC conversion unit and a second DC / DC conversion unit. A first terminal of both the first and second DC / DC conversion units is used to connect to the battery pack. A second terminal of the first DC / DC conversion unit is used to connect to a first DC bus, and a second terminal of the second DC / DC conversion unit is used to connect to a second DC bus. The first and second DC buses are configured within the power supply equipment. The power supply equipment also includes a first DC input terminal, a second DC input terminal, a first DC output terminal, and a second DC output terminal. The inverter's input terminal includes a first input terminal and a second input terminal, wherein: Both the first DC input terminal and the first DC output terminal are connected to the first DC bus. The first DC input terminal is used to connect to the first DC power generation equipment, and the first DC output terminal is used to connect to the first input terminal of the inverter. Both the second DC input terminal and the second DC output terminal are connected to the second DC bus. The second DC input terminal is used to connect to the second DC power generation equipment, and the second DC output terminal is used to connect to the second input terminal of the inverter.

10. An energy storage device, characterized in that, The energy storage device includes a power supply circuit, a battery pack, and a controller. The power supply circuit includes a DC / DC conversion unit. A first end of the DC / DC conversion unit is used to connect to the battery pack, and a second end of the DC / DC conversion unit is used to connect to a corresponding DC bus. The DC bus is also used to connect to the output end of a DC power generation device and the input end of an inverter. The controller is used to execute the control method of the power supply circuit as described in any one of claims 1-7.

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