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

Abstract

The application provides a power supply circuit control method, a power supply device and an energy storage device. The power supply circuit control method comprises the following steps: acquiring an actual grid-connected power between an AC bus and a power grid; determining a target charge-discharge power of the power supply circuit according to the actual grid-connected power and a target grid-connected power; when the target charge-discharge power is a discharge power, determining a first given power of a first DC / DC conversion unit and a second given power of a second DC / DC conversion unit according to the target charge-discharge power, and the first given power is less than or equal to the second given power; and controlling the first DC / DC conversion unit and the second DC / DC conversion unit to discharge the battery pack according to the first given power and the second given power respectively, so that the actual grid-connected power is close to the target grid-connected power, wherein in the discharge mode, the first DC / DC conversion unit and the second DC / DC conversion unit obtain electric energy from the battery pack and output to the inverter. The power supply circuit control method provided by the application can improve the efficiency of the photovoltaic system.

Description

Technical Field

[0001] This application relates to the field of photovoltaic energy storage 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] Photovoltaic power generation technology is a technology that converts solar energy into electrical energy to power loads. In related technologies, in order to make full use of solar energy resources, energy storage devices are often used to store excess solar energy supplied by photovoltaic panels to the load. At the same time, the energy stored in the energy storage devices can be provided to the load when solar energy resources are insufficient.

[0003] However, when energy storage devices are connected to multiple photovoltaic panels, and the output power of each photovoltaic panel changes, or the power demand on the load side changes, how to adjust the charging and discharging power of the energy storage device to achieve more efficient self-generation and self-consumption of solar energy becomes an urgent problem to be solved. 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 more efficient self-generation and self-consumption of solar energy.

[0005] This application provides a control method for a power supply circuit applied to a photovoltaic system. The photovoltaic system includes a battery pack, a first photovoltaic module, a second photovoltaic module, an inverter, a load, and a power supply circuit. The power supply circuit includes a first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. The first terminals of both the LLC unit and the second DC / DC conversion unit are connected to the battery pack. The second terminal of the LLC unit is connected to the first terminal of the first DC / DC conversion unit. The second terminal of the first DC / DC conversion unit is used to connect the first photovoltaic module and the first input terminal of the inverter. The second terminal of the second DC / DC conversion unit is used to connect the second photovoltaic module and the second input terminal of the inverter. The output terminal of the inverter is connected to the power grid via an AC bus. The output terminal of the inverter is also connected to the load via an AC bus. The control method includes: acquiring the actual grid-connected power between the AC bus and the power grid; determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power; when the target charging and discharging power is the discharging power, determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging and discharging power, wherein the first given power is less than or equal to the second given power; controlling the first DC / DC conversion unit and the second DC / DC conversion unit to discharge the battery pack based on the first given power and the second given power, so that the actual grid-connected power is close to the target grid-connected power, wherein, in the discharge mode, the first DC / DC conversion unit and the second DC / DC conversion unit acquire electrical energy from the battery pack and output it to the inverter.

[0006] In one embodiment, determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charge / discharge power includes: determining the first given power to be zero when the target charge / discharge power is the discharge power and the discharge power is less than the first preset power; and determining the second given power to be the discharge power.

[0007] In one embodiment, determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charge / discharge power further includes: when the target charge / discharge power is the discharge power, and the discharge power is greater than or equal to the first preset power and less than the second preset power, determining the second given power as the first preset power; and determining the first given power as the difference between the discharge power and the first preset power.

[0008] In one embodiment, determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging and discharging power further includes: when the target charging and discharging power is the discharging power, and the discharging power is greater than or equal to the second preset power, determining that both the first given power and the second given power are half of the discharging power.

[0009] In one embodiment, the control method for the power supply circuit further includes: limiting a first given power to be less than the difference between the rated maximum input power of the first input terminal of the inverter and the power generation of the first photovoltaic module; and / or limiting a second given power to be less than the difference between the rated maximum input power of the second input terminal of the inverter and the power generation of the second photovoltaic module.

[0010] In one embodiment, after determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: when the target charging and discharging power is the charging power, determining an adjustment factor based on the power generation of the first photovoltaic module and the power generation of the second photovoltaic module; determining a first given power based on the charging power and the adjustment factor; and calculating the difference between the charging power and the first given power to obtain a second given power.

[0011] In one embodiment, after determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: determining a first power generation threshold based on the difference between the power generation power of the second photovoltaic module and the preset compensation power; determining a first given power of zero when the target charging and discharging power is the charging power and the charging power is less than the first power generation threshold; and determining a second given power as the charging power.

[0012] In one embodiment, after determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: determining a first power generation threshold based on the difference between the power generation power of the second photovoltaic module and the preset compensation power; when the target charging and discharging power is the charging power and the charging power is greater than the first power generation threshold, determining the first power generation threshold as a second given power; and calculating the difference between the charging power and the first power generation threshold to obtain the first given power.

[0013] A second aspect of this application also provides a power supply device, including a power supply circuit and a controller. The power supply circuit includes a first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. A first terminal of both the LLC unit and the second DC / DC conversion unit is used to connect to a battery pack. A second terminal of the LLC unit is connected to a first terminal of the first DC / DC conversion unit. A second terminal of the first DC / DC conversion unit is used to connect to a first photovoltaic module and a first input terminal of an inverter. A second terminal of the second DC / DC conversion unit is used to connect to a second photovoltaic module and a second input terminal of an inverter. The output terminal of the inverter is connected between the power grid and a load. The controller is used to execute the control method of the power supply circuit as described in any of the preceding claims.

[0014] A third aspect of this application also provides an energy storage device, including a battery pack, a power supply circuit, and a controller. The power supply circuit includes a first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. A first terminal of the LLC unit and a first terminal of the second DC / DC conversion unit are both used to connect to the battery pack. A second terminal of the LLC unit is connected to a first terminal of the first DC / DC conversion unit. A second terminal of the first DC / DC conversion unit is used to connect a first photovoltaic module and a first input terminal of an inverter. A second terminal of the second DC / DC conversion unit is used to connect a second photovoltaic module and a second input terminal of an inverter. The output terminal of the inverter is connected between the power grid and a load. 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 obtains the actual grid-connected power between the AC bus and the grid, and determines the energy that the battery pack should currently supply to the load to reduce power consumption from the grid, or the energy that the battery pack should charge to consume the excess energy generated by the photovoltaic modules, based on the difference between the actual grid-connected power and the target grid-connected power. That is, the target charging and discharging power of the power supply circuit is determined based on the grid-connected power and the target grid-connected power. Then, based on the circuit design in the power supply circuit with corresponding DC / DC conversion units for different photovoltaic modules, the charging and discharging power of each DC / DC conversion unit in the power supply circuit can be flexibly adjusted according to the target charging and discharging power, thereby reducing power loss in the power supply circuit and improving the self-consumption efficiency of the photovoltaic system. 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 circuit block diagram of a photovoltaic system containing a power supply circuit provided in one embodiment of this application.

[0018] Figure 2 A circuit block diagram of a photovoltaic system containing a power supply circuit provided in another embodiment of this application.

[0019] Figure 3 This is a circuit diagram of a power supply circuit provided in one embodiment of this application.

[0020] Figure 4 This is a flowchart illustrating a control method for a power supply circuit provided in an embodiment of this application.

[0021] Figure 5 This is a flowchart illustrating a control method after step S402, provided in an embodiment of this application.

[0022] Figure 6 This is a flowchart illustrating a control method after step S402, provided in another embodiment of this application.

[0023] Figure 7 This is a flowchart illustrating a control method after step S402, provided in another embodiment of this application.

[0024] Figure 8 This is a control block diagram of a control method for a power supply circuit provided in an embodiment of this application.

[0025] Figure 9 A circuit block diagram of a photovoltaic system containing a power supply circuit provided in another embodiment of this application.

[0026] Figure 10 This is a structural block diagram of a power supply device provided in an embodiment of this application.

[0027] Figure 11 This is a structural block diagram of an energy storage device provided in an embodiment of this application.

[0028] Figure 12 This is a structural block diagram of a control device provided in an embodiment of this application. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Photovoltaic power generation technology is a technology that converts solar energy into electrical energy to power loads. In related technologies, in order to make full use of solar energy resources, energy storage devices are often used to store excess solar energy supplied by photovoltaic panels to the load. At the same time, the energy stored in the energy storage devices can be provided to the load when solar energy resources are insufficient.

[0034] For example, please see Figure 1 , Figure 1 This is a schematic diagram of a photovoltaic system provided in one embodiment of this application. Figure 1 As shown, the photovoltaic system includes a power supply circuit 10, a battery pack 20, a first photovoltaic module 30, a second photovoltaic module 40, and an inverter 50.

[0035] Inverter 50 is an inverter configured with multiple input channels, such as... Figure 1 As shown, the inverter 50 includes a first input terminal IN1+ / IN1- and a second input terminal IN2+ / IN2-.

[0036] Please continue to refer to this. Figure 1For example, the power supply circuit 10 includes a first DC / DC conversion unit 110, an LLC unit 120, and a second DC / DC conversion unit 130. The first terminals of both the LLC unit 120 and the second DC / DC conversion unit 130 are used to connect to the battery pack 20. The second terminal of the LLC unit 120 is connected to the first terminal of the first DC / DC conversion unit 110. The second terminal of the first DC / DC conversion unit 110 is used to connect to the first input terminals (including the first positive input terminal IN1+ and the first negative input terminal IN1-) of the first photovoltaic module 30 and the inverter 50 via a first DC bus (including the first positive DC bus DC1_BUS+ and the first negative DC bus DC1_BUS-). The second terminal of the second DC / DC conversion unit 130 is used to connect to the second input terminals (including the second positive input terminal IN2+ and the second negative input terminal IN2-) of the second photovoltaic module 40 and the inverter 50 via a second DC bus (including the second positive DC bus DC2_BUS+ and the second negative DC bus DC2_BUS-). The output of inverter 50 is connected to the power grid 60. The output of inverter 50 is also connected to load 70. Load 70 is also connected to the power grid 60.

[0037] In this application, the power supply circuit 10 is used to draw power from photovoltaic modules (e.g., the first photovoltaic module 30 and the second photovoltaic module 40) to charge the battery pack 20, or to draw power from the battery pack 20 and output it to the inverter 50. Specifically, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 are used to convert the DC power output from the battery pack 20 to voltage in discharge mode before outputting it to the inverter 50, and in charging mode, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 are used to convert the DC power output from the first photovoltaic module 30 and the second photovoltaic module 40 to voltage in charge the battery pack 20, respectively. Power transfer between the photovoltaic modules, energy storage devices, and the inverter is performed via a DC bus.

[0038] Understandably, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 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 first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 can be controlled to operate in charging mode or discharging mode, and the conversion voltage of the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 can be controlled.

[0039] LLC unit 120 is used to convert the flowing DC power to obtain electrical energy from battery pack 20 and output it to the first DC / DC conversion unit 110 in discharge mode, and to charge battery pack 20 by converting the DC power output from the first DC / DC conversion unit 110 in charging mode. LLC unit 120 may include a transformer and a full-bridge circuit, or LLC unit may include a transformer and a half-bridge circuit, etc. Understandably, since LLC unit 120 includes a transformer, it can physically isolate the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130, thereby avoiding ground loop current formed between the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 due to the common ground of battery pack 20 or inverter 50, and improving the safety of power supply circuit 10.

[0040] It should be noted that in some embodiments, the positions of LLC unit 120 and the first DC / DC conversion unit 110 can be interchanged. In this case, the second terminal of LLC unit 120 is connected to the first input terminal of the first photovoltaic module 30 and the inverter 50 via the first DC bus (including the first positive DC bus DC1_BUS+ and the first negative DC bus DC1_BUS-), and the first terminal of LLC unit 120 is connected to the first terminal of the first DC / DC conversion unit 110. The second terminal of the first DC / DC conversion unit 110 is used to connect to the battery pack 20.

[0041] The battery pack 20 contains one or more cells connected in series and / or parallel, capable of storing or releasing energy. The first photovoltaic module 30 and the second photovoltaic module 40 each include a plurality of photovoltaic panels. The photovoltaic panels are used to convert solar energy into direct current. Understandably, this application does not limit the connection method of the photovoltaic panels in the first photovoltaic module 30 and the second photovoltaic module 40.

[0042] Inverter 50 is used to obtain DC power from the first photovoltaic module 30, the second photovoltaic module 40, and / or the power supply circuit 10, and convert it into AC power to supply power to load 70. When the power demand of load 70 is less than the output power of inverter 50, inverter 50 also outputs AC power to grid 60 to feed excess energy generated by the photovoltaic system into the grid. Load 70 can be various electrical loads in a household. Grid power can be, for example, the mains power grid. Understandably, this application does not limit the type of AC power in grid 60; in other embodiments, grid 60 can be single-phase AC power, bidirectional AC power, or other multi-phase AC power, etc.

[0043] Further, please refer to Figure 2In some embodiments, the inverter 50 further includes a first MPPT (Maximum Power Point Tracking) unit 510, a second MPPT unit 520, and a power conversion unit 530. The first MPPT unit 510 is connected to the first photovoltaic module 30 and the first DC / DC conversion unit 110 via a first input terminal. The second MPPT unit 520 is connected to the second photovoltaic module 40 and the second DC / DC conversion unit 130 via a second input terminal. Thus, the first MPPT unit 510 and the second MPPT unit 520 can respectively achieve maximum power tracking of the first photovoltaic module 30 and the second photovoltaic module 40, improving energy conversion efficiency. The power conversion unit 530 is used to convert the DC power output from the first MPPT unit 510 and the second MPPT unit 520 into AC power to supply power to the load 70, and to output AC power to the grid 60 when there is surplus energy.

[0044] Understandably, in other embodiments, the number of DC / DC conversion units in the power supply circuit 10 can be adjusted according to the number of photovoltaic modules. Correspondingly, an MPPT unit is also added to the inverter 50 to perform maximum power point tracking for more photovoltaic modules. To avoid ground loops in the power supply circuit 10, when adding DC / DC conversion units, LLC units or other isolating electronic components can be provided in the branches connected to the added DC / DC conversion units. That is, when the power supply circuit 10 has multiple DC / DC power conversion branches corresponding to several photovoltaic modules, only one branch has a DC / DC conversion unit, thus preventing ground loops from forming among the multiple DC / DC conversion units in the power supply circuit 10.

[0045] Please continue reading. Figure 3 , Figure 3 This is a detailed circuit diagram of the power supply circuit 10 in one embodiment of this application. The first DC / DC conversion unit 110 includes a first inductor L1, a switching transistor Q1, and a first bus capacitor C1. The first end of the first inductor L1 is connected to the first positive DC bus DC1_BUS+, and the second end of the first inductor L1 is connected to the first end of the switching transistor Q1. The first end of the switching transistor Q1 is also connected to LLC unit 120. The second end of the switching transistor Q1 is connected to the first negative DC bus DC1_BUS-. The first end of the first bus capacitor C1 is connected between the first end of the switching transistor Q1 and LLC unit 120, and the second end of the first bus capacitor C1 is connected between the second end of the switching transistor Q1 and LLC unit 120. The controlled end of the switching transistor Q1 is connected to the controller of the power supply circuit 10 (not shown in the figure). Thus, the first inductor L1, the switching transistor Q1, and the first bus capacitor C1 together form a BOOST circuit, which can initially realize DC power conversion.

[0046] LLC unit 120 includes a switch Q2, a second inductor L2, a transformer T1, a switch Q3, and a second bus capacitor C2. The first and second terminals of switch Q2 are connected to the first and second terminals of the first capacitor C1, respectively. The first terminal of switch Q2 is also connected to the first terminal of the second inductor L2. The second terminal of the second inductor L2 is also connected to the first terminal of the first winding of transformer T1. The second terminal of the first winding of transformer T1 is also connected to the second terminal of switch Q2. The first terminal of the second winding of transformer T1 is connected to the first terminal of switch Q3. The second terminal of the second winding of transformer T1 is connected to the second terminal of switch Q3. The first and second terminals of the second bus capacitor C2 are connected to the first and second terminals of switch Q3, respectively. The second terminal of the second capacitor C2 is also connected to the negative terminal BAT- of the battery pack 20. The controlled terminals of switches Q2 and Q3 are also connected to a controller.

[0047] The second DC / DC conversion unit 130 includes a third inductor L3, a switching transistor Q5, and a third bus capacitor C3. Understandably, the circuit connection of the second DC / DC conversion unit 130 is largely the same as that of the first DC / DC conversion unit 110, and will not be described again here. Furthermore, the third inductor L3, the switching transistor Q5, and the third bus capacitor C3 also form a BOOST circuit, enabling DC power conversion.

[0048] The power supply circuit 10 also includes switching transistors Q4 and Q6. The second terminal of switching transistor Q4 is connected to the first terminal of bus capacitor C2, and the first terminal of switching transistor Q4 is connected to the positive power supply terminal BAT+ of battery pack 20. The second terminal of switching transistor Q6 is connected to the first terminal of bus capacitor C3, and the first terminal of switching transistor Q6 is connected to the positive power supply terminal BAT+ of battery pack 20. The second terminal of the third capacitor C3 is connected to the negative power supply terminal BAT- of battery pack 20.

[0049] Thus, the controller of the power supply circuit 10 can control the on / off logic and duty cycle of the switching transistors Q1 to Q6 in the power supply circuit 10 to enable the power supply circuit 10 to obtain the power of the photovoltaic module to charge the battery pack 20, and to obtain the power of the battery pack 20 and output it to the inverter 50.

[0050] Understandably, this application does not limit the specific circuit structure of the first DC / DC conversion unit 110, LLC unit 120 and the second DC / DC conversion unit 130. In other embodiments, those skilled in the art can adjust the first DC / DC conversion unit 110, LLC unit 120 and the second DC / DC conversion unit 130, as long as the first DC / DC conversion unit 110, LLC unit 120 and the second DC / DC conversion unit 130 can still perform the corresponding functions described in this application.

[0051] However, as Figure 1 or Figure 2 As shown, when the battery pack 20 is connected to multiple photovoltaic panels, when the output power of each photovoltaic panel changes, that is, when the output power of each photovoltaic module changes, or when the power demand on the load side changes, how to adjust the charging and discharging power of the battery pack 20 through the power supply circuit 10 to achieve more efficient self-generation and self-consumption of solar energy becomes an urgent problem to be solved.

[0052] Therefore, this application provides a power supply circuit control method that can flexibly adjust the charging and discharging power of the battery pack 20, thereby improving the self-generation efficiency of the battery pack 20. In the following embodiments, the power supply circuit control method is applied to the power supply circuit 10 as an example to illustrate the solution of this application. In other embodiments, when the power supply circuit 10 includes three or more DC / DC conversion units, the power supply circuit control method provided in this application can also be applied.

[0053] Please continue reading. Figure 4 , Figure 4 This is a flowchart illustrating a control method for a power supply circuit provided in this application. It is understood that the control method for this power supply circuit can be executed by a controller (not shown) of the power supply circuit 10. The control method for this power supply circuit includes the following steps:

[0054] Step S401: Obtain the actual grid-connected power between the AC bus and the power grid.

[0055] The actual grid-connected power represents the power supply relationship between the inverter 50 and load 70 connected to the AC bus and the power grid 60. In this application, the actual grid-connected power can be positive, negative, or zero, depending on the energy flow direction between the inverter 50, load 70, and power grid 60. For example, when the inverter 50 outputs 10W to the power grid 60, the actual grid-connected power between the inverter 50, load 70, and power grid 60 is 10W; when the power grid 60 outputs 10W to the load 70, the actual grid-connected power between the inverter 50, load 70, and power grid 60 is -10W; when the output power of the inverter 50 exactly meets the power demand of the load 70, i.e., when the inverter 50 outputs no power to the power grid 60 and the power grid 60 outputs no power to the load 70, the actual grid-connected power is zero.

[0056] Understandably, a grid monitoring module (not shown in the figure) can be installed between the local microgrid system consisting of the photovoltaic system and the load 70 and the power grid 60, that is, between the common connection point of the inverter 50 output terminal and the load 70 and the power grid 60. The grid monitoring module is used to monitor the actual grid-connected power between the power grid 60 and the AC bus. In this way, the controller of the power supply circuit 10 can obtain the actual power output from the inverter 50 to the power grid 60, or from the power grid to the load 70, by communicating with the grid monitoring module. In some embodiments, the grid monitoring module can be a smart meter, and the smart meter can display the actual grid-connected power.

[0057] Understandably, the communication between the controller and the power grid monitoring module can be wireless communication (such as Bluetooth communication, ZigBee communication, etc.) or wired communication (such as serial communication based on RS-485 serial bus, or Controller Area Network (CAN) bus, or other parallel communication methods). This application does not limit the specific communication method.

[0058] In other embodiments, the controller can communicate with the inverter 50 and the load 70 to obtain the actual output power of the inverter 50 and the actual power consumption of the load 70, thereby calculating the actual grid-connected power based on the actual output power and the actual power consumption.

[0059] Step S402: Determine the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power.

[0060] The target grid-connected power is used to characterize the ideal value of the actual grid-connected power between the AC bus and the power grid. For example, in some embodiments, the target grid-connected power can be 0, in which case the battery pack 20, the first photovoltaic module 30, and the second photovoltaic module 40 can meet the power demand of the load 70 without drawing power from the grid 60 to supply power to the load 70. Understandably, this application does not limit the specific value of the target grid-connected power.

[0061] Understandably, when the actual grid-connected power is greater than the target grid-connected power, it means that the power output of inverter 50 to grid 60 is greater than expected. In this case, the energy output by the first photovoltaic module 30 and the second photovoltaic module 40 can be stored in the battery pack 20 by charging the battery pack 20. When the actual grid-connected power is less than the target grid-connected power, it means that the power output of inverter 50 is insufficient to meet the needs of load 70, and load 70 draws power from the grid. In this case, the output power of inverter 50 can be increased by discharging the battery pack 20, thereby reducing the power draw from grid 60.

[0062] Thus, in step S402, the target charging and discharging power of the power supply circuit 10 can be determined based on the difference between the actual grid-connected power and the target grid-connected power, thereby controlling the battery pack 20 to charge or discharge according to the target charging and discharging power.

[0063] Understandably, the target charging / discharging power of the power supply circuit 10 can be either charging power or discharging power. Specifically, when the actual grid-connected power is greater than the target grid-connected power, the target charging / discharging power is the charging power, and the controller can control the battery pack 20 to charge based on the charging power. When the actual grid-connected power is less than the target grid-connected power, the target charging / discharging power is the discharging power, and the controller can control the battery pack 20 to discharge based on the discharging power.

[0064] In some embodiments, when the actual grid-connected power is greater than the target grid-connected power, the value obtained by subtracting the target grid-connected power from the actual grid-connected power can be used as the charging power; when the actual grid-connected power is less than the target grid-connected power, the value obtained by subtracting the actual grid-connected power from the target grid-connected power can be used as the discharging power.

[0065] This application does not limit the specific calculation method of the target charging and discharging power obtained in step S402, as long as it satisfies the inventive concept of determining the target charging and discharging power based on the difference between the actual grid-connected power and the target grid-connected power. For example, in some other embodiments, the power loss in the photovoltaic system can be further combined to determine the target charging and discharging power of the power supply circuit 10 based on the difference between the actual grid-connected power and the target grid-connected power.

[0066] Step S403: When the target charge / discharge power is the discharge power, determine the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit according to the target charge / discharge power, and the first given power is less than or equal to the second given power.

[0067] Understandably, the first given power is the ideal charging / discharging power of the first DC / DC conversion unit 110, and the second given power is the ideal charging / discharging power of the second DC / DC conversion unit 130. Furthermore, in this application, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 are always charging or discharging simultaneously. Thus, when the target charging / discharging power is the discharging power, both the first and second given powers are given discharging powers; when the target charging / discharging power is the charging power, both the first and second given powers are given charging powers. The sum of the first and second given powers is the target charging / discharging power.

[0068] Understandably, since the branch containing the first DC / DC conversion unit 110 also includes the LLC unit 120, the power loss during power conversion in the branch containing the first DC / DC conversion unit 110 will be greater than that in the branch containing the second DC / DC conversion unit 130. Therefore, when the target charging / discharging power is the same as the discharging power, by setting the first given power to be less than or equal to the second given power, the power loss in the power supply circuit 10 can be reduced, and the discharge efficiency of the battery pack 20 can be improved.

[0069] Step S404: Control the first DC / DC conversion unit and the second DC / DC conversion unit to discharge the battery pack according to the first given power and the second given power, so that the actual grid-connected power is close to the target grid-connected power. In the discharge mode, the first DC / DC conversion unit and the second DC / DC conversion unit obtain electrical energy from the battery pack and output it to the inverter.

[0070] Understandably, with a first given power as the adjustment target, the first DC / DC converter 110 is then subjected to closed-loop control via a deviation controller, such as a P-controller (proportional controller), a PI-regulator (proportional-integral controller), or a PID-controller (proportional-integral-derivative controller), to make the output power of the first DC / DC converter 110 to the inverter 50 close to the first given power. Similarly, the second DC / DC converter 130 can also adopt a substantially similar approach to make the output power of the second DC / DC converter 130 to the inverter 50 close to the second given power.

[0071] Thus, by executing step S404, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 can obtain electrical energy from the battery pack 20 according to the first given power and the second given power, respectively, and output power to the inverter 50, so that the battery pack 20 supplies power to the load 70, thereby reducing the power drawn from the grid 60 and improving the self-consumption efficiency of the photovoltaic system.

[0072] Understandably, the control method of the power supply circuit 10 provided in this application first obtains the actual grid-connected power between the AC bus and the power grid 60, and determines the energy that the battery pack 20 should currently supply to the load 70 to reduce power consumption from the grid, or the energy that the battery pack 20 should charge to consume the excess energy generated by the photovoltaic modules, based on the difference between the actual grid-connected power and the target grid-connected power. That is, the target charging and discharging power of the power supply circuit 10 is determined based on the grid-connected power and the target grid-connected power. Then, based on the circuit design of the power supply circuit 10, which has corresponding DC / DC conversion units for different photovoltaic modules, the charging and discharging power of each DC / DC conversion unit in the power supply circuit 10 can be flexibly adjusted according to the target charging and discharging power, thereby reducing the power loss in the power supply circuit 10 and improving the self-consumption efficiency of the battery pack 20.

[0073] In some embodiments, step S403 includes:

[0074] When the target charge / discharge power is the discharge power and the discharge power is less than the first preset power, the first given power is determined to be zero; and the second given power is determined to be the discharge power.

[0075] The first preset power is the power threshold for simultaneously activating the branch containing the first DC / DC conversion unit 110 and the branch containing the second DC / DC conversion unit 130 to participate in power conversion. For example, the first preset power could be 800W.

[0076] Understandably, as the discharge power increases, the heat generated by the transmission lines on the electronic devices also increases; that is, as the discharge power increases, the power loss also increases. Furthermore, the power loss in the branch where the first DC / DC conversion unit 110 is located is relatively large. Therefore, the first preset power can be determined under laboratory conditions.

[0077] In some embodiments, the criterion for determining the first preset power can be: the minimum power when the load 70 is in standby low power consumption. It can be understood that when the load 70 is in standby low power consumption, its power demand is relatively small. At this time, the losses caused by different branch topologies account for a large proportion of the total power consumption. Therefore, branches with lower power losses should be prioritized.

[0078] It should be understood that the first preset power can change dynamically depending on the number of loads connected to the AC bus.

[0079] In some embodiments, when the first preset power configuration is appropriate, the power loss when power conversion is performed only through the second DC / DC conversion unit 130 when the discharge power is the first preset power is equal to the power loss when both the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 participate in power conversion simultaneously.

[0080] Thus, when the target charging and discharging power is the discharge power and the discharge power is less than the first preset power, only the second DC / DC conversion unit 130 can be activated to perform power conversion, so as to avoid the power loss generated when the branch where the first DC / DC conversion unit 110 is located participates in power conversion, thereby reducing the power loss of the power supply circuit 10.

[0081] In some embodiments, step S403 includes:

[0082] When the target charging / discharging power is the discharge power, and the discharge power is greater than or equal to the first preset power and less than the second preset power, the second given power is determined to be the first preset power; and the first given power is determined to be the difference between the discharge power and the first preset power.

[0083] The second preset power can be twice the first preset power. When the discharge power is greater than the second preset power, it can be assumed that the power required by the load 70 is larger, and the loss due to topology differences in the total power loss can be almost ignored.

[0084] Understandably, when the discharge power is greater than or equal to the first preset power, it means that the branches containing the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 can be activated simultaneously to participate in power conversion. Furthermore, since the second DC / DC conversion unit 130 must be activated first during the discharge power increase process, meaning the second given power reaches the first preset power first, it can be determined that the first given power is the difference between the discharge power and the first preset power; that is, the second given power is controlled to be greater than the first given power.

[0085] In some embodiments, step S403 includes:

[0086] When the target charge / discharge power is the discharge power, and the discharge power is greater than or equal to the second preset power, both the first given power and the second given power are determined to be half of the discharge power.

[0087] Understandably, when the discharge power is greater than or equal to the second preset power, it indicates that the power required by the load 70 is relatively large. Therefore, the power loss difference between the branch where the second DC / DC conversion unit 130 is located and the branch where the first DC / DC conversion unit 110 is located can be ignored compared to the power loss generated when the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 participate in power conversion at the same time. Thus, by directly determining that the first given power and the second given power are both half of the discharge power, the algorithm complexity can be reduced and controller resources can be saved.

[0088] Thus, by executing the above steps in step S403, when the photovoltaic system draws power from the grid, the branch where the second DC / DC conversion unit 130 is located can participate in the discharge first, thereby reducing circuit losses and improving the self-generation and self-consumption efficiency of the photovoltaic system.

[0089] Understandably, the first preset power is less than or equal to the maximum output power of the second DC / DC conversion unit 130. And when the first preset power is equal to the maximum output power of the second DC / DC conversion unit 130 and the first preset power is equal to the maximum output power of the first DC / DC conversion unit 110, it is not necessary to perform the step when the discharge power is greater than the second preset power and the second preset power is twice the first preset power, so as to ensure the safety of the power supply circuit 10.

[0090] Understandably, the specific value of the first preset power can be adjusted according to factors such as the minimum power of the load 70 and the power loss in the photovoltaic system. This application does not limit the specific value of the first preset power.

[0091] In some embodiments, the control method for the power supply circuit further includes:

[0092] Limit the first given power to be less than the difference between the rated maximum input power of the first input terminal of the inverter and the power generation of the first photovoltaic module; and / or

[0093] The second given power is limited to the difference between the rated maximum input power of the second input terminal of the grid-connected inverter and the power generation of the second photovoltaic module.

[0094] Understandably, in some embodiments, the controller can obtain the code and corresponding rated maximum input power of each input terminal of the inverter 50 by communicating with the inverter 50. In other embodiments, the code and corresponding rated maximum input power of each input terminal of the inverter 50 can be preset in the controller of the power supply circuit 10. Further, the power generation of each photovoltaic module can be obtained in real time by setting a sensor (e.g., a Hall sensor, or other power measurement sensor) at the output terminal of each photovoltaic module and communicating with the sensor. In this way, the controller can limit the given power of each DC / DC conversion unit connected to the input terminal of the inverter 50 based on the rated maximum input power of each input terminal of the inverter 50 and the power generation of the photovoltaic module connected to each input terminal.

[0095] Understandably, in the above embodiments, by limiting the first given power and / or the second given power, the sum of the output power of the first DC / DC conversion unit 110 and the power generation of the first photovoltaic module 30 is always less than the maximum input power of the first input terminal of the inverter 50; and / or the sum of the output power of the second DC / DC conversion unit 130 and the power generation of the second photovoltaic module 40 is always less than the maximum input power of the second input terminal of the inverter 50, so as to ensure that the input power of the two input terminals of the inverter 50 will not exceed the maximum power, thereby ensuring that the inverter 50 will not be damaged.

[0096] Please see Figure 5 In some embodiments, after step S402 is executed, the control method for the power supply circuit further includes:

[0097] Step S501: When the target charging and discharging power is the charging power, the adjustment factor is determined based on the power generation of the first photovoltaic module and the power generation of the second photovoltaic module.

[0098] Understandably, when the target charging and discharging power is the charging power, that is, in charging mode, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 draw power from the first photovoltaic module 30 and the second photovoltaic module 40 respectively to charge the battery pack 20.

[0099] Furthermore, since the first photovoltaic module 30 and the second photovoltaic module 40 are positioned differently, their illumination conditions at the same time may also differ, which in turn may lead to differences in their power generation at the same time. Accordingly, the input power of the first DC / DC conversion unit 110 should be less than the power generation of the first photovoltaic module 30, and the input power of the second DC / DC conversion unit 130 should be less than the power generation of the second photovoltaic module 40.

[0100] In step S501, the adjustment factor is used to characterize the proportional relationship between the first given power and the charging power. Since the target charge / discharge power determined in step S402 is the charging power, the sum of the first given power of the first DC / DC conversion unit 110 and the second given power of the second DC / DC conversion unit 130 is the charging power, and the first given power is less than the power generation of the first photovoltaic module 30, and the second given power is less than the power generation of the second photovoltaic module 40. Thus, the adjustment factor can be determined based on the proportional relationship between the power generation of the first photovoltaic module 30 and the sum of the power generation of the first photovoltaic module 30 and the power generation of the second photovoltaic module 40. For example, the adjustment factor can be calculated using the following formula:

[0101] K = P1 / (P1 + P2)

[0102] Where K is the adjustment factor, P1 is the power generation of the first photovoltaic module 30, and P2 is the power generation of the second photovoltaic module 40.

[0103] Step S502: Determine the first given power based on the charging power and adjustment factor.

[0104] In step S502, the product of the charging power and the adjustment factor is used as the first given power.

[0105] Step S503: Calculate the difference between the charging power and the first given power to obtain the second given power.

[0106] Thus, by executing steps S501 to S503, when the target charging / discharging power is the charging power, the first given power of the first DC / DC conversion unit 110 and the second given power of the second DC / DC conversion unit 130 can be determined. This allows the first DC / DC conversion unit 110 to be controlled to use the first given power as the target power, and the second DC / DC conversion unit 130 to be controlled to use the second given power as the target power to charge the battery pack 20. This ensures the safety of the power supply circuit 10 while storing the surplus energy of the photovoltaic module through the battery pack 20.

[0107] Please see Figure 6 In some embodiments, after step S402 is executed, the control method for the power supply circuit further includes:

[0108] Step S601: Determine the first power generation threshold based on the difference between the power generation of the second photovoltaic module and the preset compensation power.

[0109] The preset compensation power represents the minimum power required to maintain the operation of the second MPPT unit 520 in the inverter 50. Thus, the first power generation threshold is the maximum power that the second DC / DC conversion unit 130, connected to the second photovoltaic module 40, can obtain from the second photovoltaic module 40.

[0110] Step S602: When the target charging and discharging power is the charging power and the charging power is less than the first power generation threshold, the first given power is determined to be zero.

[0111] Step S603: Determine the second given power as the charging power.

[0112] Understandably, since the power loss on the branch where the first DC / DC conversion unit 110 is located is greater than that on the branch where the second DC / DC conversion unit 130 is located, when the target charging / discharging power is the charging power and the charging power is less than the first power generation threshold, the energy from the second photovoltaic module 40 is preferentially obtained through the second DC / DC conversion unit 130 to charge the battery pack 20, thereby reducing the power loss of the power supply circuit 10. Simultaneously, since at least a preset compensation power is reserved for output to the second input terminal, maximum power tracking of the inverter 50 to the second photovoltaic module 40 can be maintained, thus maximizing the self-consumption efficiency of the photovoltaic system while ensuring the normal operation of the inverter 50.

[0113] Please see Figure 7 In some embodiments, after step S402 is executed, the control method for the power supply circuit further includes:

[0114] Step S701: Determine the first power generation threshold based on the difference between the power generation of the second photovoltaic module and the preset compensation power.

[0115] Similarly, in step S701, the preset compensation power characterizes the minimum power required to maintain the normal operation of the second MPPT unit 520 in the inverter 50. The first power generation threshold is the maximum power that the second DC / DC conversion unit 130 connected to the second photovoltaic module 40 can obtain from the second photovoltaic module 40.

[0116] Step S702: When the target charging and discharging power is the charging power and the charging power is greater than the first power generation threshold, the first power generation threshold is determined to be the second given power.

[0117] Step S703: Calculate the difference between the charging power and the first power generation threshold to obtain the first given power.

[0118] The controller further limits the first given power to be less than a second power generation threshold. The second power generation threshold is the difference between the power generation of the first photovoltaic module 30 and the minimum power required for the first MPPT unit 510 in the inverter 50 to operate normally. This prevents the first DC / DC conversion unit 110 from malfunctioning when the first given power exceeds the power generation of the first photovoltaic module. Thus, while maintaining maximum power point tracking (MPPT) of the first MPPT unit 510 to the first photovoltaic module 30, the self-consumption efficiency of the photovoltaic system is maximized.

[0119] Thus, by executing steps S701 to S703, when the target charging / discharging power is the charging power and the charging power is greater than the first power generation threshold, energy from the second photovoltaic module 40 is preferentially obtained through the second DC / DC conversion unit 130 to charge the battery pack 20, reducing the power loss of the power supply circuit 10. Simultaneously, since the first MPPT unit 510 and the second MPPT unit 520 of the inverter 50 can maintain the minimum power required for normal operation, the inverter 50 can also maintain maximum power point tracking of the first photovoltaic module 30 and the second photovoltaic module 40, thereby maximizing the self-consumption efficiency of the photovoltaic system.

[0120] Please continue reading. Figure 8 , Figure 8 This diagram illustrates a specific control block diagram of a control method for a power supply circuit provided in an embodiment of this application, implemented using a closed-loop control algorithm. The following is based on... Figure 8 The specific control block diagram shown illustrates the detailed workflow of the power supply circuit control method:

[0121] First, the actual grid-connected power P_real between the AC bus and the power grid is obtained, and the target charging / discharging power P_tref of the power supply circuit is determined based on the actual grid-connected power P_real and the target grid-connected power P_aim. Then, the first given power P_ref1 of the first DC / DC conversion unit 110 and the second given power P_ref2 of the second DC / DC conversion unit 130 are determined by the calculation unit 81. Understandably, the calculation unit 81 is pre-set with various calculation rules based on the above embodiments, so that the calculation unit 81 can calculate the first given power P_ref1 and the second given power P_ref2 based on the obtained target charging / discharging power P_tref.

[0122] After determining the first given power P_ref1 and the second given power P_ref2, the first deviation controller 82 performs closed-loop control on the first DC / DC conversion unit 110 to make the first output power P_out1 output by the first DC / DC conversion unit 110 to the inverter 50 close to the first given power P_ref1. The second deviation controller 83 performs closed-loop control on the second DC / DC conversion unit 130 to make the second output power P_out2 output by the second DC / DC conversion unit 130 to the inverter 50 close to the second given power P_ref2. Understandably, the sign of the first output power P_out1 is used to indicate the energy direction between the first DC / DC conversion unit 110 and the inverter 50. For example, when the signs of the first output power P_out1 and the second output power P_out2 are both positive, it means that both the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 obtain the power from the battery pack 20 and output it to the DC bus; when the signs of the first output power P_out1 and the second output power P_out2 are both negative, it means that the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 respectively obtain the power from the first photovoltaic module 30 and the second photovoltaic module 40 on the DC bus and output it to the battery pack 20 to charge the battery pack 20.

[0123] Furthermore, the first DC / DC conversion unit 110 and the second DC / DC conversion unit 130 output first output power P_out1 and second output power P_out2 to the DC buses (DC1_BUS and DC2_BUS), respectively, and the total power generation P_pv of the first photovoltaic module 30 and the second photovoltaic module 40, thus determining the output power P_OUT of the inverter 50. Simultaneously, the actual grid-connected power P_real can be calculated based on the output power P_OUT of the inverter 50 and the power demand P_load of the load 70. In some embodiments, the actual grid-connected power P_real can also be measured by a smart meter.

[0124] In some embodiments, the actual grid-connected power P_real and the target grid-connected power P_aim can also be used as inputs to the third deviation controller after the difference is calculated, and the target charging and discharging power P_tref of the power supply circuit can be calculated through closed-loop control.

[0125] The first deviation controller 82, the second deviation controller 83, and the third deviation controller mentioned above can be existing controllers in related technologies, such as PI controllers (proportional integral controllers), PID controllers (proportional integral differential controllers), etc., and this application does not impose any restrictions on them.

[0126] In summary, the control method of the power supply circuit 10 provided in this application first obtains the actual grid-connected power between the AC bus and the power grid 60, and determines the energy that the battery pack 20 should currently supply to the load 70 to reduce power consumption from the grid, or the energy that the battery pack 20 should charge to consume the excess energy generated by the photovoltaic modules, based on the difference between the actual grid-connected power and the target grid-connected power. That is, the target charging and discharging power of the power supply circuit 10 is determined based on the grid-connected power and the target grid-connected power. Then, based on the circuit design of the power supply circuit 10, which has corresponding DC / DC conversion units for different photovoltaic modules, the charging and discharging power of each DC / DC conversion unit in the power supply circuit 10 can be flexibly adjusted according to the target charging and discharging power, thereby reducing the power loss in the power supply circuit 10 and improving the self-generation and self-consumption efficiency of the battery pack 20.

[0127] Please continue reading. Figure 9 Understandably, in other embodiments, the power supply circuit 10 may also connect to three or more photovoltaic modules. Accordingly, the photovoltaic modules connected in the power supply circuit 10 are also provided with a branch formed by the Nth DC / DC conversion unit 140 and the Nth LLC unit 150, so as to obtain the power output by the Nth photovoltaic module 80 to charge the battery pack 20, or obtain the power output by the battery pack 20 and output it to the corresponding input terminal of the inverter 50.

[0128] Understandably, when the power supply circuit 10 includes three or more DC / DC conversion units, the given power corresponding to each DC / DC conversion unit can still be determined according to the methods described in the above embodiments or the same inventive concept.

[0129] For example, when the target charging / discharging power is the discharge power, the second given power corresponding to the second DC / DC conversion unit 130 is always greater than or equal to the given power corresponding to other DC / DC conversion units.

[0130] When the discharge power is less than the first preset power, the second given power is determined to be the discharge power, and other given powers are zero;

[0131] When the discharge power is greater than or equal to the first preset power and less than the third preset power, the second given power is determined to be the first preset power; the given power corresponding to the DC / DC conversion unit other than the second DC / DC conversion unit 130 is determined to be the difference between the discharge power and the first preset power, divided by the number of DC / DC conversion units minus 1. The third preset power can be three times the first preset power.

[0132] When the discharge power is greater than the third preset power, the given power corresponding to each DC / DC conversion unit is determined to be the quotient obtained by dividing the discharge power by the number of DC / DC conversion units.

[0133] For example, when the target charging and discharging power is the charging power, the adjustment factor corresponding to each DC / DC conversion unit can be determined according to the proportion of the power generation of each photovoltaic module to the power generation of all photovoltaic modules; and then the given power corresponding to each DC / DC conversion unit can be determined according to the adjustment factor.

[0134] When the target charging and discharging power is the charging power, the first power generation threshold can be determined as the second given power of the second DC / DC conversion unit 130. Other DC / DC conversion units can be the difference between the charging power and the first power generation threshold, divided by the number of DC / DC conversion units minus 1.

[0135] Thus, when the power supply circuit 10 is connected to three or more photovoltaic modules, the given power of each DC / DC conversion unit in the power supply circuit 10 can still be adjusted according to the target charging and discharging power based on the basic concept of the present invention, thereby improving the self-generation and self-consumption efficiency of the photovoltaic system.

[0136] Please continue reading. Figure 10 An embodiment of this application also provides a power supply device 100, comprising at least a first DC / DC conversion unit 110, an LLC unit 120, a second DC / DC conversion unit 130, and a controller 1100. The first terminals of both the LLC unit 120 and the second DC / DC conversion unit 130 are used to connect to a battery pack 20. The second terminal of the LLC unit 120 is connected to the first terminal of the first DC / DC conversion unit 110. The second terminal of the first DC / DC conversion unit is used to connect a first photovoltaic module 30 and a first input terminal of an inverter 50, and the second terminal of the second DC / DC conversion unit 130 is used to connect a second photovoltaic module 40 and a second input terminal of the inverter 50. The output terminal of the inverter 50 is connected between the power grid 60 and a load 70. The controller 1100 is used to execute the control method of the power supply circuit as described above.

[0137] Thus, by executing the power supply circuit control method described above through the controller 1100, the charging and discharging power of each DC / DC conversion unit in the power supply equipment 100 can be flexibly adjusted according to the target charging and discharging power, thereby reducing power loss in the power supply equipment and improving the self-generation and self-consumption efficiency of the photovoltaic system.

[0138] Understandably, the power supply device 100 can be integrated into an electronic device equipped with a battery module, or it can be set up independently.

[0139] Please continue reading. Figure 11 An embodiment of this application also provides an energy storage device 200, including a battery pack 20, a controller 2100, and a power supply circuit 10 as described above. The battery pack 20 is connected to the first terminal of the LLC unit 120 of the power supply circuit 10 and the first terminal of the second DC / DC conversion unit 130.

[0140] Understandably, when the energy storage device 200 includes a power supply circuit 10, the controller of the power supply circuit 10 can be integrated with the controller in the battery pack 20 as the same controller, such as controller 2100. In this way, the controller 2100 of the energy storage device 200 can control the charging and discharging power of each DC / DC conversion unit in the power supply circuit 10 while realizing the charging and discharging management of the battery pack 20.

[0141] Understandably, the energy storage device 200 using the power supply circuit 10 can flexibly adjust the charging and discharging power of each DC / DC conversion unit of the power supply circuit 10 according to the target charging and discharging power, thereby reducing the power loss in the power supply circuit 10 and improving the self-generation and self-consumption efficiency of the photovoltaic system.

[0142] This application also provides a control device applied to a power supply circuit. 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:

[0143] The acquisition module 310 is used to acquire the actual grid-connected power between the AC bus and the power grid.

[0144] The determination module 320 is used to determine the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power.

[0145] The determining module 320 is further configured to determine the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging / discharging power when the target charging / discharging power is the discharge power, wherein the first given power is less than or equal to the second given power.

[0146] The control module 330 is used to control the first DC / DC conversion unit and the second DC / DC conversion unit to discharge the battery pack according to the first given power and the second given power, so that the actual grid-connected power is close to the target grid-connected power. In the discharge mode, the first DC / DC conversion unit and the second DC / DC conversion unit obtain electrical energy from the battery pack and output it to the inverter.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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).

[0153] 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.

[0154] 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, said power supply circuit being applied to a photovoltaic system, characterized in that, The photovoltaic system includes a battery pack, a first photovoltaic module, a second photovoltaic module, an inverter, and a power supply circuit. The power supply circuit includes a first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. The first terminal of the LLC unit and the first terminal of the second DC / DC conversion unit are both connected to the battery pack. The second terminal of the LLC unit is connected to the first terminal of the first DC / DC conversion unit. The second terminal of the first DC / DC conversion unit is used to connect the first photovoltaic module and the first input terminal of the inverter. The second terminal of the second DC / DC conversion unit is used to connect the second photovoltaic module and the second input terminal of the inverter. The output terminal of the inverter is connected to the power grid via an AC bus, and the output terminal of the inverter is also connected to a load via the AC bus. The control method includes: Obtain the actual grid-connected power between the AC bus and the power grid; The target charging and discharging power of the power supply circuit is determined based on the actual grid-connected power and the target grid-connected power. When the target charge / discharge power is the discharge power, the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit are determined according to the target charge / discharge power, and the first given power is less than or equal to the second given power; The first DC / DC conversion unit discharges the battery pack according to the first given power, and the second DC / DC conversion unit discharges the battery pack according to the second given power, so that the actual grid-connected power is close to the target grid-connected power. In the discharge mode, the first DC / DC conversion unit and the second DC / DC conversion unit obtain electrical energy from the battery pack and output it to the inverter.

2. The method according to claim 1, characterized in that, Determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging / discharging power includes: When the target charge / discharge power is the discharge power, and the discharge power is less than the first preset power, the first given power is determined to be zero; and, The second given power is determined to be the discharge power.

3. The method according to claim 1, characterized in that, The step of determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging and discharging power further includes: When the target charge / discharge power is the discharge power, and the discharge power is greater than or equal to the first preset power and less than the second preset power, the second given power is determined to be the first preset power. The first given power is determined to be the difference between the discharge power and the first preset power.

4. The method according to claim 1, characterized in that, The step of determining the first given power of the first DC / DC conversion unit and the second given power of the second DC / DC conversion unit based on the target charging and discharging power further includes: When the target charge / discharge power is the discharge power, and the discharge power is greater than or equal to the second preset power, it is determined that both the first given power and the second given power are half of the discharge power.

5. The method according to any one of claims 2-4, characterized in that, The method further includes: Limiting the first given power to be less than the difference between the rated maximum input power of the first input terminal of the inverter and the power generation of the first photovoltaic module; and / or The second given power is limited to be less than the difference between the rated maximum input power of the second input terminal of the inverter and the power generation of the second photovoltaic module.

6. The method according to claim 1, characterized in that, After determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: When the target charging and discharging power is the charging power, the adjustment factor is determined based on the power generation of the first photovoltaic module and the power generation of the second photovoltaic module; The first given power is determined based on the charging power and the adjustment factor; The difference between the charging power and the first given power is calculated to obtain the second given power.

7. The method according to claim 1, characterized in that, After determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: The first power generation threshold is determined based on the difference between the power generation of the second photovoltaic module and the preset compensation power. When the target charging / discharging power is the charging power and the charging power is less than the first power generation threshold, the first given power is determined to be zero. The second given power is determined to be the charging power.

8. The method according to claim 1, characterized in that, After determining the target charging and discharging power of the power supply circuit based on the actual grid-connected power and the target grid-connected power, the method further includes: The first power generation threshold is determined based on the difference between the power generation of the second photovoltaic module and the preset compensation power. When the target charging and discharging power is the charging power, and the charging power is greater than the first power generation threshold, the first power generation threshold is determined to be the second given power. The difference between the charging power and the first power generation threshold is calculated to obtain the first given power.

9. 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 first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. The first terminal of the LLC unit and the first terminal of the second DC / DC conversion unit are both used to connect to a battery pack. The second terminal of the LLC unit is connected to the first terminal of the first DC / DC conversion unit. The second terminal of the first DC / DC conversion unit is used to connect to a first photovoltaic module and a first input terminal of an inverter. The second terminal of the second DC / DC conversion unit is used to connect to a second photovoltaic module and a second input terminal of the inverter. The output terminal of the inverter is connected to the power grid. The output terminal of the inverter is also connected to a load via an AC bus. The controller is used to execute the control method of the power supply circuit as described in any one of claims 1-8.

10. An energy storage device, characterized in that, The energy storage device includes a battery pack, a power supply circuit, and a controller. The power supply circuit includes a first DC / DC conversion unit, a second DC / DC conversion unit, and an LLC unit. The first terminal of the LLC unit and the first terminal of the second DC / DC conversion unit are both used to connect to the battery pack. The second terminal of the LLC unit is connected to the first terminal of the first DC / DC conversion unit. The second terminal of the first DC / DC conversion unit is used to connect to a first photovoltaic module and a first input terminal of an inverter. The second terminal of the second DC / DC conversion unit is used to connect to a second photovoltaic module and a second input terminal of the inverter. The output terminal of the inverter is connected to the power grid. The output terminal of the inverter is also connected to a load via an AC bus. The controller is used to execute the control method of the power supply circuit as described in any one of claims 1-8.

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