Photovoltaic energy storage DCDC converter and control method thereof

Abstract

The invention provides a photovoltaic energy storage DCDC converter and a control method thereof. The converter comprises a photovoltaic module; an energy storage battery; the switchable step-up and step-down circuit is electrically connected with the positive electrode of the photovoltaic module and the positive electrode of the energy storage battery, and is used for switching the voltage of the photovoltaic module when the voltage of the photovoltaic module is smaller than that of the energy storage battery; when the voltage of the photovoltaic module is larger than or equal to the voltage of the energy storage battery, the charging voltage is increased on the basis of the photovoltaic module until the target voltage difference value is smaller than or equal to the preset difference value, and then the energy storage battery is charged. On the basis of the photovoltaic module, the charging voltage is reduced until the target voltage difference value is smaller than or equal to the preset difference value, the energy storage battery is charged, the target voltage difference value is the difference value between the charging voltage and the voltage of the energy storage battery, and the converter can compare the photovoltaic voltage with the voltage of the energy storage battery; therefore, whether the photovoltaic voltage is connected to the high voltage side or the low voltage side is switched and selected.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power supplies, and in particular to a photovoltaic energy storage DCDC converter and a control method for the photovoltaic energy storage DCDC converter. Background Art

[0002] In the prior art, the output voltage of the photovoltaic module is generally converted into a DC bus voltage through a DCDC converter. When charging, the DC bus voltage is converted into a battery voltage through a second DCDC converter to charge the battery. The prior art solution has undergone two DCDC conversions, which increases the conversion power loss, reduces the energy storage efficiency, and increases the equipment cost.

[0003] In the existing DCDC converter technology solution, when using the BUCK-BOOST topology, because BUCK-BOOST can only step down or step up in one direction, when the photovoltaic power source is connected to the high voltage side and the battery is connected to the low voltage side, it can only be charged when the photovoltaic voltage is higher than the battery voltage, and it cannot be charged when the photovoltaic voltage is lower than the battery voltage. Or when the photovoltaic power source is connected to the low voltage side and the battery is connected to the high voltage side, it can only be charged when the photovoltaic voltage is lower than the battery voltage, and it cannot be charged when the photovoltaic voltage is higher than the battery voltage. The above situations limit the working range of the DCDC converter. Summary of the invention

[0004] The main purpose of the present application is to provide a photovoltaic energy storage DCDC converter to at least solve the problem that the existing DCDC converter technical solution can only step down or step up in one direction, cannot adapt to different voltage values ​​of the photovoltaic voltage, and limits the working range of the DCDC converter.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a photovoltaic energy storage DCDC converter is provided, comprising: a photovoltaic component; an energy storage battery, wherein the negative electrode of the energy storage battery is electrically connected to the negative electrode of the photovoltaic component; and a switchable boost-drop circuit, wherein the switchable boost-drop circuit is electrically connected to the positive electrode of the photovoltaic component and the positive electrode of the energy storage battery, respectively. The switchable boost-drop circuit is used to charge the energy storage battery by increasing the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference when the voltage of the photovoltaic component is less than the voltage of the energy storage battery. The switchable boost-drop circuit is also used to charge the energy storage battery by reducing the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery.

[0006] Optionally, the switchable boost-drop circuit includes: a boost-drop selection unit, a first end of the boost-drop selection unit is electrically connected to the positive electrode of the photovoltaic component, a second end of the boost-drop selection unit is electrically connected to the positive electrode of the energy storage battery, the boost-drop selection unit is used to connect the photovoltaic component to the low voltage side and the energy storage battery to the high voltage side when the voltage of the photovoltaic component is less than the voltage of the energy storage battery, and the boost-drop selection unit is also used to connect the photovoltaic component to the high voltage side and the energy storage battery to the low voltage side when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery; an inductor unit, a first end of the inductor unit is electrically connected to the third end of the boost-drop selection unit; a switch unit, a first end of the switch unit is electrically connected to the second end of the inductor unit, a second end of the switch unit is electrically connected to the negative electrode of the photovoltaic component and the negative electrode of the energy storage battery respectively, and a third end of the switch unit is electrically connected to the fourth end of the boost-drop selection unit.

[0007] Optionally, the boost / drop selection unit includes: a first bidirectional switch, having a common end, a first selection end, and a second selection end, the common end of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection end of the first bidirectional switch is electrically connected to the first end of the inductor unit, and the second selection end of the first bidirectional switch is electrically connected to the third end of the switch unit; a second bidirectional switch, having a common end, a first selection end, and a second selection end, the common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductor unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively.

[0008] Optionally, the switch unit includes: a first switch device, having a control end, a first end and a second end, the control end of the first switch device is used to input a first drive signal, the first end of the first switch device is electrically connected to the second end of the inductor unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic component and the negative electrode of the energy storage battery respectively; a second switch device, having a control end, a first end and a second end, the control end of the second switch device is used to input a second drive signal, the first end of the second switch device is electrically connected to the second end of the inductor unit, and the second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit respectively.

[0009] Optionally, the switchable boost-drop circuit also includes: a first voltage detection unit, electrically connected to the photovoltaic component, and used to detect the voltage value of the photovoltaic component; a second voltage detection unit, electrically connected to the energy storage battery, and used to detect the voltage value of the energy storage battery.

[0010] According to another aspect of the present application, a control method for a photovoltaic energy storage DCDC converter is provided, and the control method is used to control any one of the photovoltaic energy storage DCDC converters, and the method includes: obtaining the voltage of a photovoltaic component as a photovoltaic voltage; obtaining the voltage of an energy storage battery as an energy storage battery voltage; comparing the photovoltaic voltage with the energy storage battery voltage to obtain a comparison result; and according to the comparison result, determining to increase the charging voltage based on the photovoltaic component until a target voltage difference is less than or equal to a preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery.

[0011] Optionally, according to the comparison result, it is determined whether to increase the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, including: when the voltage of the photovoltaic component is less than the voltage of the energy storage battery, increasing the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery; when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery, reducing the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery.

[0012] Optionally, the switchable boost-drop circuit includes an electrically connected boost-drop selection unit, an inductance unit and a switch unit, the boost-drop selection unit includes a first bidirectional switch and a second bidirectional switch, the common end of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection end of the first bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the first bidirectional switch is electrically connected to the third end of the switch unit; the common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively. The third end of the switch unit is electrically connected, the switch unit includes a first switch device and a second switch device, the control end of the first switch device is used to input a first drive signal, the first end of the first switch device is electrically connected to the second end of the inductor unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic module and the negative electrode of the energy storage battery respectively; the control end of the second switch device is used to input a second drive signal, the first end of the second switch device is electrically connected to the second end of the inductor unit, and the second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit respectively. Then, when the voltage of the photovoltaic assembly is less than the voltage of the energy storage battery, the charging voltage is increased based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery, including: when the voltage of the photovoltaic assembly is less than the voltage of the energy storage battery, the first path of the first bidirectional switch is controlled to be turned on and the second path of the first bidirectional switch is turned off, and the second path of the second bidirectional switch is controlled to be turned on and the first path of the second bidirectional switch is turned off, wherein the first path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the first selection end of the first bidirectional switch, the second path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the second selection end of the first bidirectional switch, the first path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the first selection end of the second bidirectional switch, and the second path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the second selection end of the second bidirectional switch; the first switch device is controlled to be turned on and the second switch device is turned off, so that the charging current generated by the photovoltaic assembly passes through the first path of the first bidirectional switch, the inductor unit and the first switch device in sequence, so as to increase the charging voltage in the inductor unit until the target voltage difference is less than or equal to the preset difference;When the target voltage difference is less than or equal to the preset difference, the first switch device and the second switch device are both controlled to be turned off, so that the charging voltage in the inductor unit generates the charging current and sequentially passes through the freewheeling diode in the second switch device and the second path of the second bidirectional switch to charge the energy storage battery. ;

[0013] Optionally, controlling the first switching device to turn on includes: setting a duty cycle of a first drive signal; generating the first drive signal according to the duty cycle; inputting the first drive signal to a control end of the first switching device to control the first switching device to turn on, wherein the duty cycle is proportional to the magnitude of the charging current.

[0014] Optionally, the switchable boost-drop circuit includes an electrically connected boost-drop selection unit, an inductance unit and a switch unit, the boost-drop selection unit includes a first bidirectional switch and a second bidirectional switch, the common end of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection end of the first bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the first bidirectional switch is electrically connected to the third end of the switch unit; the common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively, the switch unit includes a first switch device and a second switch device, the control end of the first switch device is used to input a first drive signal, the first end of the first switch device is electrically connected to the second end of the inductance unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic component and the negative electrode of the energy storage battery respectively; the control end of the second switch device is used to input a second drive signal, and the first end of the second switch device is electrically connected to the negative electrode of the photovoltaic component and the negative electrode of the energy storage battery respectively; one end is electrically connected to the second end of the inductor unit, and the second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit, respectively. When the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery, the charging voltage is reduced based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery, including: when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery, the second path of the first bidirectional switch is controlled to be turned on and the first path of the first bidirectional switch is turned off, and the first path of the second bidirectional switch is controlled to be turned on and the second path of the second bidirectional switch is turned off; the first switch device is controlled to be turned off and the second switch device is controlled to be turned on, so that the charging current generated by the photovoltaic component passes through the second path of the first bidirectional switch, the second switch device and the inductor unit in sequence, so as to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery.

[0015] Applying the technical solution of the present application, the above-mentioned photovoltaic energy storage DCDC converter includes: a photovoltaic module; an energy storage battery, the negative electrode of the energy storage battery is electrically connected to the negative electrode of the photovoltaic module; a switchable boost-drop circuit, the switchable boost-drop circuit is electrically connected to the positive electrode of the photovoltaic module and the positive electrode of the energy storage battery respectively, the switchable boost-drop circuit is used to increase the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is less than the voltage of the energy storage battery, and the switchable boost-drop circuit is also used to reduce the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery. The converter charges the energy storage battery by converting the voltage through only one-stage DCDC converter, which reduces the DCDC conversion power loss, improves the energy storage efficiency, and reduces the equipment cost. In addition, the converter can automatically switch between boost charging and buck charging according to the comparison between the photovoltaic voltage and the battery voltage, thereby broadening the working range of the DCDC converter and making it more convenient to charge the energy storage from photovoltaics. This solves the problem that the existing DCDC converter technical solution can only buck or boost in one direction and cannot adapt to different voltage values ​​of the photovoltaic voltage, thus limiting the working range of the DCDC converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of a photovoltaic energy storage DCDC converter provided in an embodiment of the present application is shown;

[0018] Figure 2 A schematic diagram of the structure of another photovoltaic energy storage DCDC converter provided in an embodiment of the present application is shown;

[0019] Figure 3 A schematic diagram of the structure of another photovoltaic energy storage DCDC converter provided in an embodiment of the present application is shown;

[0020] Figure 4 A schematic flow chart of a control method for a photovoltaic energy storage DCDC converter provided in an embodiment of the present application is shown;

[0021] Figure 5 A schematic flow chart of another method for controlling a photovoltaic energy storage DCDC converter provided in an embodiment of the present application is shown.

[0022] The above drawings include the following reference numerals:

[0023] 10. Photovoltaic module; 20. Energy storage battery; 30. Switchable boost-drop circuit; 31. Boost-drop selection unit; 311. First bidirectional switch; 312. Second bidirectional switch; 32. Inductor unit; 33. Switch unit; 331. First switch device; 332. Second switch device; 34. First voltage detection unit; 35. Second voltage detection unit. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] For the convenience of description, some nouns or terms involved in the embodiments of the present application are explained below:

[0028] DC-DC Converter: Direct Current-Direct Current, abbreviated as DCDC.

[0029] As introduced in the background technology, in the prior art, when the BUCK-BOOST topology is used, because the BUCK-BOOST can only step down or step up in one direction, when the photovoltaic power source is connected to the high voltage side and the battery is connected to the low voltage side, it can only be charged when the photovoltaic voltage is higher than the battery voltage, and it cannot be charged when the photovoltaic voltage is lower than the battery voltage. Or when the photovoltaic power source is connected to the low voltage side and the battery is connected to the high voltage side, it can only be charged when the photovoltaic voltage is lower than the battery voltage, and it cannot be charged when the photovoltaic voltage is higher than the battery voltage. In order to solve the problem that the existing DCDC converter technical solution can only step down or step up in one direction, cannot adapt to different voltage values ​​of the photovoltaic voltage, and limits the working range of the DCDC converter, the embodiments of the present application provide a photovoltaic energy storage DCDC converter and a control method for the photovoltaic energy storage DCDC converter.

[0030] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0031] Figure 1 1 is a flow chart of a photovoltaic energy storage DCDC converter according to an embodiment of the present application. Figure 1 As shown, the photovoltaic energy storage DCDC converter includes: a photovoltaic module 10; an energy storage battery 20, wherein the negative electrode of the energy storage battery 20 is electrically connected to the negative electrode of the photovoltaic module 10; and a switchable boost-drop circuit 30, wherein the switchable boost-drop circuit 30 is electrically connected to the positive electrode of the photovoltaic module 10 and the positive electrode of the energy storage battery 20, respectively. The switchable boost-drop circuit 30 is used to charge the energy storage battery 20 by increasing the charging voltage based on the photovoltaic module 10 until the target voltage difference is less than or equal to the preset difference when the voltage of the photovoltaic module 10 is less than the voltage of the energy storage battery 20. The switchable boost-drop circuit 30 is also used to charge the energy storage battery 20 by reducing the charging voltage based on the photovoltaic module 10 until the target voltage difference is less than or equal to the preset difference when the voltage of the photovoltaic module 10 is greater than or equal to the voltage of the energy storage battery 20, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery 20.

[0032] The photovoltaic energy storage DCDC converter of the present application comprises: a photovoltaic module; an energy storage battery, wherein the negative electrode of the energy storage battery is electrically connected to the negative electrode of the photovoltaic module; and a switchable boost-drop circuit, wherein the switchable boost-drop circuit is electrically connected to the positive electrode of the photovoltaic module and the positive electrode of the energy storage battery respectively. The switchable boost-drop circuit is used to increase the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is less than the voltage of the energy storage battery. The switchable boost-drop circuit is also used to reduce the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery. The converter charges the energy storage battery by converting the voltage through only one-stage DCDC converter, which reduces the DCDC conversion power loss, improves the energy storage efficiency, and reduces the equipment cost. In addition, the converter can automatically switch between boost charging and buck charging according to the comparison between the photovoltaic voltage and the battery voltage, thereby broadening the working range of the DCDC converter and making it more convenient to charge the energy storage from photovoltaics. This solves the problem that the existing DCDC converter technical solution can only buck or boost in one direction and cannot adapt to different voltage values ​​of the photovoltaic voltage, thus limiting the working range of the DCDC converter.

[0033] In some instances, such as Figure 2 As shown, the switchable boost-drop circuit 30 includes: a boost-drop selection unit 31, a first end of the boost-drop selection unit 31 is electrically connected to the positive electrode of the photovoltaic component 10, and a second end of the boost-drop selection unit 31 is electrically connected to the positive electrode of the energy storage battery 20. The boost-drop selection unit 31 is used to connect the photovoltaic component 10 to the low voltage side and the energy storage battery 20 to the high voltage side when the voltage of the photovoltaic component 10 is less than the voltage of the energy storage battery 20. The boost-drop selection unit 31 is also used to connect the photovoltaic component 10 to the low voltage side and the energy storage battery 20 to the high voltage side when the voltage of the photovoltaic component 10 is greater than or equal to In the case of the voltage of the energy storage battery 20, the photovoltaic module 10 is connected to the high voltage side and the energy storage battery 20 is connected to the low voltage side; the inductor unit 32, the first end of the inductor unit 32 is electrically connected to the third end of the boost and drop selection unit 31; the switch unit 33, the first end of the switch unit 33 is electrically connected to the second end of the inductor unit 32, the second end of the switch unit 33 is electrically connected to the negative electrode of the photovoltaic module 10 and the negative electrode of the energy storage battery 20 respectively, and the third end of the switch unit 33 is electrically connected to the fourth end of the boost and drop selection unit 31.

[0034] Among them, Figure 3As shown, the inductor unit includes an inductor L. The allowable current of the inductor depends on the actual maximum operating current. The allowable current of the inductor needs to be greater than the actual maximum operating current and leave a certain margin. For example: when the actual maximum operating current is 10A, an inductor with an allowable current of 13A is generally selected. The inductance of the inductor depends on the input voltage, output voltage, current flowing through, switching frequency, etc. Generally, the larger the difference between the input voltage and the output voltage, the larger the inductance; generally, the smaller the difference between the input voltage and the output voltage, the larger the inductance. The larger the switching frequency, the smaller the inductance. The general inductance is between 50uH and 15mH.

[0035] The step-up / down selection unit is used to select whether to switch the photovoltaic voltage to the high voltage side or the low voltage side according to the voltage relationship between the photovoltaic component and the energy storage battery. The inductor unit is used to store the charging voltage provided by the photovoltaic component to the energy storage battery. By controlling the conduction and disconnection of each switch device in the switch unit, the charging circuit of the photovoltaic component to charge the energy storage battery can be controlled.

[0036] In some instances, such as Figure 2 As shown, the boost-drop selection unit 31 includes: a first bidirectional switch 311, having a common terminal a1, a first selection terminal b1 and a second selection terminal c1, the common terminal a1 of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component 10, the first selection terminal b1 of the first bidirectional switch is electrically connected to the first end of the inductor unit 32, and the second selection terminal c1 of the first bidirectional switch is electrically connected to the third end of the switch unit 33; a second bidirectional switch 312, having a common terminal a2, a first selection terminal b2 and a second selection terminal c2, the common terminal a2 of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery 20, the first selection terminal b2 of the second bidirectional switch is electrically connected to the first end of the inductor unit 32, and the second selection terminal c2 of the second bidirectional switch is electrically connected to the second selection terminal c1 of the first bidirectional switch 311 and the third end of the switch unit 33 respectively.

[0037] The two terminals PV+ and PV- of the output voltage of the solar photovoltaic module are respectively connected to the two terminals of the DCDC converter, and PV+ is connected to the terminal a1 of the first bidirectional switch. PV- is connected to the P-terminal of the DCDC converter. The voltage port of the energy storage battery includes BAT+ and BAT-, wherein BAT- is connected to the P-terminal of the DCDC converter, and BAT+ of the energy storage battery is connected to the terminal a2 of the second bidirectional switch of the DCDC converter.

[0038] By controlling the connection relationship between the terminals of the first bidirectional switch and the second bidirectional switch, it is selected whether the photovoltaic power source is connected to the high voltage side or the low voltage side, and the photovoltaic power source and the energy storage battery are connected to the appropriate circuit interface.

[0039] In some instances, such as Figure 2 As shown, the switch unit 33 includes: a first switch device 331, having a control end, a first end and a second end, the control end of the first switch device 331 is used to input a first drive signal, the first end of the first switch device 331 is electrically connected to the second end of the inductor unit 32, and the second end of the first switch device 331 is electrically connected to the negative electrode of the photovoltaic component 10 and the negative electrode of the energy storage battery 20 respectively; a second switch device 332, having a control end, a first end and a second end, the control end of the second switch device 332 is used to input a second drive signal, the first end of the second switch device 332 is electrically connected to the second end of the inductor unit 32, and the second end of the second switch device 332 is electrically connected to the second selection end of the first bidirectional switch 311 in the boost-drop selection unit 31 and the second selection end of the second bidirectional switch 312 in the boost-drop selection unit 31 respectively.

[0040] The first switch device and the second switch device can be transistors or N-type MOS tubes, and the first switch device and the second switch device are both composed of a switch tube and a resistor. By controlling the operating frequency and duty cycle of the first switch device and the second switch device, the voltage, current and charging power of the energy storage battery can be controlled.

[0041] like Figure 3 As shown, the inductor L, the first switch device 331 and the second switch device 332 form a BUCK-BOOST circuit topology. P1+ is the high voltage port of this BUCK-BOOST circuit topology. P2+ is the low voltage port of this BUCK-BOOST circuit topology. The photovoltaic energy storage DCDC converter adopts the BUCK-BOOST circuit topology, which can compare the photovoltaic voltage and the battery voltage, so as to switch and select whether the photovoltaic voltage is connected to the high voltage side or the low voltage side.

[0042] In some instances, such as Figure 3 As shown, the switchable boost-drop circuit further includes: a first voltage detection unit 34, electrically connected to the photovoltaic component 10, and the first voltage detection unit 34 is used to detect the voltage value of the photovoltaic component 10; a second voltage detection unit 35, electrically connected to the energy storage battery 20, and the second voltage detection unit 35 is used to detect the voltage value of the energy storage battery 20.

[0043] By detecting the voltage of the photovoltaic module and the voltage of the energy storage battery and comparing the two, the conduction path of the first bidirectional switch and the second bidirectional switch is controlled to select whether the photovoltaic power source is connected to the high voltage side or the low voltage side, and the photovoltaic power source and the energy storage battery are connected to the appropriate circuit interface.

[0044] Figure 41 is a flow chart of a control method for a photovoltaic energy storage DCDC converter according to an embodiment of the present application. The control method is used to control any of the above-mentioned photovoltaic energy storage DCDC converters, such as Figure 4 As shown, the method comprises the following steps:

[0045] Step S101, obtaining the voltage of the photovoltaic module as the photovoltaic voltage;

[0046] Specifically, the photovoltaic component can be a solar photovoltaic cell.

[0047] Step S102, obtaining the voltage of the energy storage battery as the energy storage battery voltage;

[0048] Specifically, the energy storage battery may be a storage battery.

[0049] Step S103, comparing the photovoltaic voltage with the energy storage battery voltage to obtain a comparison result;

[0050] Specifically, the photovoltaic voltage is compared with the battery voltage, and the photovoltaic power source is selected to be connected to the high voltage side or the low voltage side. Figure 3 The first bidirectional switch and the second bidirectional switch in the photovoltaic power source and the energy storage battery are connected to a suitable circuit interface.

[0051] Step S104, based on the comparison result, determine whether to increase the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery.

[0052] Specifically, when the photovoltaic voltage is lower than the battery voltage, the photovoltaic voltage can be boosted to charge the battery, which can broaden the operating range of the DCDC converter.

[0053] In some examples, according to the comparison result, determining to increase the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery comprises the following steps:

[0054] Step S201, when the voltage of the photovoltaic module is lower than the voltage of the energy storage battery, the charging voltage is increased based on the photovoltaic module until the target voltage difference is lower than or equal to the preset difference, so as to charge the energy storage battery;

[0055] Step S202, when the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, based on the photovoltaic module, the charging voltage is reduced until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery.

[0056] Specifically, the photovoltaic energy storage DCDC converter adopts the BUCK-BOOST circuit topology, which can compare the photovoltaic voltage and the battery voltage, and thus switch to select whether the photovoltaic voltage is connected to the high voltage side or the low voltage side. The preset difference can be 5V-0V.

[0057] Among them, Figure 3 As shown, the switchable boost-drop circuit includes an electrically connected boost-drop selection unit 31, an inductance unit 32 and a switch unit 33, the boost-drop selection unit 31 includes a first bidirectional switch 311 and a second bidirectional switch 312, the common end a1 of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component 10, the first selection end b1 of the first bidirectional switch is electrically connected to the first end of the inductance unit 32, and the second selection end c1 of the first bidirectional switch is electrically connected to the third end of the switch unit 33; the common end a2 of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery 20, the first selection end b2 of the second bidirectional switch is electrically connected to the first end of the inductance unit 32, and the second selection end c2 of the second bidirectional switch is electrically connected to the second selection end b1 of the first bidirectional switch and the third end of the switch unit 33 respectively. The third end of the switching element 33 is electrically connected, the switching unit 33 includes a first switching device 331 and a second switching device 332, the control end of the first switching device 331 is used to input a first driving signal, the first end of the first switching device 331 is electrically connected to the second end of the inductor unit 32, and the second end of the first switching device 331 is electrically connected to the negative electrode of the photovoltaic component 10 and the negative electrode of the energy storage battery 20 respectively; the control end of the second switching device 332 is used to input a second driving signal, the first end of the second switching device 332 is electrically connected to the second end of the inductor unit 32, and the second end of the second switching device 332 is electrically connected to the second selection end c1 of the first bidirectional switch in the boost-drop selection unit 31 and the second selection end c2 of the second bidirectional switch in the boost-drop selection unit 31 respectively.

[0058] In the case where the voltage of the photovoltaic assembly is lower than the voltage of the energy storage battery, the charging voltage is increased based on the photovoltaic assembly until the target voltage difference is lower than or equal to the preset difference to charge the energy storage battery, comprising the following steps:

[0059] Step S2011, when the voltage of the photovoltaic module is lower than the voltage of the energy storage battery, the first path of the first bidirectional switch is controlled to be turned on and the second path of the first bidirectional switch is turned off, and the second path of the second bidirectional switch is controlled to be turned on and the first path of the second bidirectional switch is turned off, wherein the first path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the first selection end of the first bidirectional switch, the second path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the second selection end of the first bidirectional switch, the first path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the first selection end of the second bidirectional switch, and the second path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the second selection end of the second bidirectional switch;

[0060] Step S2012, controlling the first switch device to be turned on and the second switch device to be turned off, so that the charging current generated by the photovoltaic assembly passes through the first path of the first bidirectional switch, the inductor unit and the first switch device in sequence, so as to increase the charging voltage in the inductor unit until the target voltage difference is less than or equal to the preset difference;

[0061] Step S2013, when the target voltage difference is less than or equal to the preset difference, control the first switch device and the second switch device to be cut off, so that the charging voltage in the inductor unit generates the charging current and passes through the freewheeling diode in the second switch device and the second path of the second bidirectional switch in sequence to charge the energy storage battery.

[0062] Specifically, when the voltage of the above-mentioned photovoltaic component is lower than the voltage of the above-mentioned energy storage battery, the photovoltaic component is set on the low-voltage side and the energy storage battery is set on the high-voltage side to boost the voltage of the photovoltaic component, so that the photovoltaic voltage is increased to be greater than or equal to the energy storage battery to charge the energy storage battery.

[0063] In some instances, controlling the conduction of the first switching device includes: setting a duty cycle of the first drive signal; generating the first drive signal according to the duty cycle; inputting the first drive signal to the control end of the first switching device to control the conduction of the first switching device, wherein the duty cycle is proportional to the magnitude of the charging current.

[0064] Specifically, when the solar photovoltaic component charges the battery and the photovoltaic voltage is lower than the battery voltage, the first switch device, the inductor L, and the second switch device form a BOOST boost circuit to boost the photovoltaic voltage Vdc1 to the energy storage battery voltage Vdc2 to charge the battery.

[0065] The working principle of BOOST charging is as follows: the first switch device is turned on, the current of PV+ flows through the inductor L and the first switch device into P-. Since the inductor L can store electrical energy, the current passing through the inductor L gradually increases. The longer the first switch device is turned on, the greater the current passing through the inductor, and the higher the electrical energy stored in the inductor. When the first switch device is turned off, the electrical energy stored in the inductor will be charged to the energy storage battery through the freewheeling diode in the second switch device. At this time, the voltage VL across the inductor plus the photovoltaic voltage Vdc1 and the voltage VD2 on the freewheeling diode in the second switch device are equal to or higher than the battery voltage, thereby realizing the function of the current flowing into the battery for charging through the freewheeling diode in the second switch device.

[0066] By adjusting the operating frequency or duty cycle of the switch tube, the on-time of the first switch device is adjusted. For example, the larger the duty cycle, the longer the on-time of the first switch device. The longer the on-time of the first switch device, the higher the electric energy stored in the inductor. The higher the electric energy stored in the inductor, the higher the voltage VL across the inductor after the first switch device is turned off.

[0067] The voltage Vdc2 of the energy storage battery is determined by the battery itself. When VL+Vdc1+VD2 is slightly higher than Vdc2, the current flows from VL+Vdc1+VD2 to Vdc2. By adjusting the size of VL, the size of the current flowing into the battery can be adjusted. For example, if the battery voltage is 310Vdc, VL+Vdc1+VD2 is 311Vdc, and photovoltaics can charge the battery. Increasing VL, so that VL+Vdc1+VD2 rises to 312Vdc, the voltage difference becomes larger, and the charging current becomes larger. The charging current becomes larger, and the charging power increases.

[0068] In some instances, such as Figure 3As shown, the switchable boost-drop circuit includes an electrically connected boost-drop selection unit 31, an inductance unit 32 and a switch unit 33, the boost-drop selection unit 31 includes a first bidirectional switch 311 and a second bidirectional switch 312, the common end a1 of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component 10, the first selection end b1 of the first bidirectional switch is electrically connected to the first end of the inductance unit 32, and the second selection end c1 of the first bidirectional switch is electrically connected to the third end of the switch unit 33; the common end a2 of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery 20, the first selection end b2 of the second bidirectional switch is electrically connected to the first end of the inductance unit 32, and the second selection end c2 of the second bidirectional switch is electrically connected to the second selection end c1 of the first bidirectional switch and the third end of the switch unit 33 respectively. The third end of the switch unit 33 is electrically connected to the third end of the inductor unit 33, the switch unit 33 includes a first switch device 331 and a second switch device 332, the control end of the first switch device 331 is used to input a first drive signal, the first end of the first switch device 331 is electrically connected to the second end of the inductor unit 32, and the second end of the first switch device 331 is electrically connected to the negative electrode of the photovoltaic component 10 and the negative electrode of the energy storage battery 20 respectively; the control end of the second switch device 332 is used to input a second drive signal, the first end of the second switch device 332 is electrically connected to the second end of the inductor unit 32, and the second end of the second switch device 332 is electrically connected to the second selection end c1 of the first bidirectional switch in the boost-drop selection unit 31 and the second selection end c2 of the second bidirectional switch in the boost-drop selection unit 31 respectively,

[0069] In the case where the voltage of the photovoltaic assembly is greater than or equal to the voltage of the energy storage battery, the charging voltage is reduced based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery, comprising the following steps:

[0070] Step S2021, when the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, controlling the second path of the first bidirectional switch to be turned on and the first path of the first bidirectional switch to be turned off, and controlling the first path of the second bidirectional switch to be turned on and the second path of the second bidirectional switch to be turned off;

[0071] Step S2022, control the above-mentioned first switch device to be cut off and the above-mentioned second switch device to be turned on, so that the charging current generated by the above-mentioned photovoltaic component passes through the second path of the above-mentioned first bidirectional switch, the above-mentioned second switch device and the above-mentioned inductor unit in sequence, so as to reduce the above-mentioned charging voltage based on the above-mentioned photovoltaic component until the above-mentioned target voltage difference is less than or equal to the above-mentioned preset difference, so as to charge the above-mentioned energy storage battery.

[0072] Specifically, when the voltage of the photovoltaic assembly is greater than or equal to the voltage of the energy storage battery, the photovoltaic assembly is set on the high voltage side and the energy storage battery is set on the low voltage side to charge the energy storage battery.

[0073] The control method of the photovoltaic energy storage DCDC converter of the present application is used to control any one of the photovoltaic energy storage DCDC converters, and the method includes: obtaining the voltage of the photovoltaic component as the photovoltaic voltage; obtaining the voltage of the energy storage battery as the energy storage battery voltage; comparing the photovoltaic voltage with the energy storage battery voltage to obtain a comparison result; according to the comparison result, determining to increase the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery. The method charges the energy storage battery by converting the voltage through only one-stage DCDC converter, thereby reducing the DCDC conversion power loss, improving the energy storage efficiency, and reducing the equipment cost. In addition, the method can automatically switch between boost charging or buck charging according to the comparison between the photovoltaic voltage and the battery voltage, thereby broadening the working range of the DCDC converter, making photovoltaic charging of energy storage more convenient, and solving the problem that the existing DCDC converter technical solution can only buck or boost in one direction, cannot adapt to different voltage values ​​of the photovoltaic voltage, and limits the working range of the DCDC converter.

[0074] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the control method of the photovoltaic energy storage DCDC converter of the present application will be described in detail below in combination with specific embodiments.

[0075] This embodiment relates to a specific control method of a photovoltaic energy storage DCDC converter, such as Figure 3 and Figure 5 As shown, the following steps are included:

[0076] Step S1: Detecting the photovoltaic voltage Vdc1; detecting the energy storage battery voltage Vdc2;

[0077] Step S2: Compare the values ​​of Vdc1 and Vdc2;

[0078] Step S3: If Vdc1≥Vdc2, the photovoltaic is connected to the high voltage side P2+, and the battery is connected to the low voltage side P1+. The DCDC main control circuit controls a1 and c1 of the first bidirectional switch to be turned on, and controls a2 and b2 of the second bidirectional switch to be turned on. The DCDC main control circuit controls the second switch device to work, and the second switch device and the inductor L form a BUCK step-down circuit to reduce the photovoltaic voltage to the battery voltage and charge the battery. By controlling the operating frequency and duty cycle of the second switch device, the voltage, current and charging power of the battery can be controlled.

[0079] Step S4: If Vdc1<Vdc2, the photovoltaic is connected to the low voltage side P1+, and the battery is connected to the high voltage side P2+. The DCDC main control circuit controls a1 and b1 of the first bidirectional switch to be turned on, and controls a2 and c2 of the second bidirectional switch to be turned on. The DCDC main control circuit controls the operation of the first switch device, and the first switch device and the inductor L form a Boost circuit to boost the photovoltaic voltage to the battery voltage to charge the battery. By controlling the operating frequency and duty cycle of the first switch device, the voltage, current and charging power of the battery are controlled.

[0080] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0081] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0082] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0083] 1) The photovoltaic energy storage DCDC converter of the present application comprises: a photovoltaic module; an energy storage battery, the negative electrode of the energy storage battery is electrically connected to the negative electrode of the photovoltaic module; a switchable boost-drop circuit, the switchable boost-drop circuit is electrically connected to the positive electrode of the photovoltaic module and the positive electrode of the energy storage battery respectively, the switchable boost-drop circuit is used to increase the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is less than the voltage of the energy storage battery, and the switchable boost-drop circuit is also used to reduce the charging voltage based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery. The converter charges the energy storage battery by converting the voltage through only one-stage DCDC converter, which reduces the DCDC conversion power loss, improves the energy storage efficiency, and reduces the equipment cost. In addition, the converter can automatically switch between boost charging and buck charging according to the comparison between the photovoltaic voltage and the battery voltage, thereby broadening the working range of the DCDC converter and making it more convenient to charge the energy storage from photovoltaics. This solves the problem that the existing DCDC converter technical solution can only buck or boost in one direction and cannot adapt to different voltage values ​​of the photovoltaic voltage, thus limiting the working range of the DCDC converter.

[0084] 2) The control method of the photovoltaic energy storage DCDC converter of the present application is used to control any one of the photovoltaic energy storage DCDC converters mentioned above, and the method includes: obtaining the voltage of the photovoltaic component as the photovoltaic voltage; obtaining the voltage of the energy storage battery as the energy storage battery voltage; comparing the photovoltaic voltage with the energy storage battery voltage to obtain a comparison result; according to the comparison result, determining to increase the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or, based on the photovoltaic component, reducing the charging voltage until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery. The method charges the energy storage battery by converting the voltage through only one-stage DCDC converter, thereby reducing the DCDC conversion power loss, improving the energy storage efficiency, and reducing the equipment cost. In addition, the method can automatically switch between boost charging or buck charging according to the comparison between the photovoltaic voltage and the battery voltage, thereby broadening the working range of the DCDC converter, making photovoltaic charging of energy storage more convenient, and solving the problem that the existing DCDC converter technical solution can only buck or boost in one direction, cannot adapt to different voltage values ​​of the photovoltaic voltage, and limits the working range of the DCDC converter.

[0085] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A photovoltaic energy storage DCDC converter, characterized in that: include: Photovoltaic panels; An energy storage battery, wherein the negative electrode of the energy storage battery is electrically connected to the negative electrode of the photovoltaic module; A switchable boost-drop circuit, the switchable boost-drop circuit is electrically connected to the positive electrode of the photovoltaic component and the positive electrode of the energy storage battery respectively, the switchable boost-drop circuit is used to increase the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic component is less than the voltage of the energy storage battery, and the switchable boost-drop circuit is also used to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery.

2. The photovoltaic energy storage DCDC converter according to claim 1, characterized in that: The switchable boost-drop circuit comprises: A boost-drop selection unit, wherein a first end of the boost-drop selection unit is electrically connected to the positive electrode of the photovoltaic component, and a second end of the boost-drop selection unit is electrically connected to the positive electrode of the energy storage battery. The boost-drop selection unit is used to connect the photovoltaic component to the low voltage side and the energy storage battery to the high voltage side when the voltage of the photovoltaic component is less than the voltage of the energy storage battery. The boost-drop selection unit is also used to connect the photovoltaic component to the high voltage side and the energy storage battery to the low voltage side when the voltage of the photovoltaic component is greater than or equal to the voltage of the energy storage battery. an inductor unit, wherein a first end of the inductor unit is electrically connected to a third end of the boost-drop selection unit; A switch unit, wherein the first end of the switch unit is electrically connected to the second end of the inductor unit, the second end of the switch unit is electrically connected to the negative electrode of the photovoltaic module and the negative electrode of the energy storage battery respectively, and the third end of the switch unit is electrically connected to the fourth end of the boost / drop selection unit.

3. The photovoltaic energy storage DCDC converter according to claim 2, characterized in that: The boost and drop selection unit comprises: a first bidirectional switch, having a common terminal, a first selection terminal and a second selection terminal, wherein the common terminal of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection terminal of the first bidirectional switch is electrically connected to the first terminal of the inductor unit, and the second selection terminal of the first bidirectional switch is electrically connected to the third terminal of the switch unit; The second bidirectional switch has a common end, a first selection end and a second selection end. The common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductor unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively.

4. The photovoltaic energy storage DCDC converter according to claim 2, characterized in that: The switch unit comprises: a first switch device, having a control end, a first end and a second end, wherein the control end of the first switch device is used to input a first drive signal, the first end of the first switch device is electrically connected to the second end of the inductor unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic module and the negative electrode of the energy storage battery respectively; The second switch device has a control end, a first end, and a second end. The control end of the second switch device is used to input a second drive signal. The first end of the second switch device is electrically connected to the second end of the inductor unit. The second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit, respectively.

5. The photovoltaic energy storage DCDC converter according to claim 1, characterized in that: The switchable boost-drop circuit further includes: a first voltage detection unit, electrically connected to the photovoltaic assembly, and configured to detect a voltage value of the photovoltaic assembly; The second voltage detection unit is electrically connected to the energy storage battery, and the second voltage detection unit is used to detect the voltage value of the energy storage battery.

6. A control method for a photovoltaic energy storage DCDC converter, characterized in that: The control method is used to control the photovoltaic energy storage DCDC converter according to any one of claims 1 to 5, and the method comprises: The voltage of the photovoltaic module is obtained as the photovoltaic voltage; The voltage of the energy storage battery is obtained as the energy storage battery voltage; Comparing the photovoltaic voltage with the energy storage battery voltage to obtain a comparison result; According to the comparison result, it is determined whether to increase the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, wherein the target voltage difference is the difference between the charging voltage and the voltage of the energy storage battery.

7. The method according to claim 6, characterized in that According to the comparison result, determining to increase the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, or to reduce the charging voltage based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery, including: When the voltage of the photovoltaic module is lower than the voltage of the energy storage battery, the charging voltage is increased based on the photovoltaic module until the target voltage difference is lower than or equal to the preset difference, so as to charge the energy storage battery; When the voltage of the photovoltaic assembly is greater than or equal to the voltage of the energy storage battery, the charging voltage is reduced based on the photovoltaic assembly until the target voltage difference is less than or equal to the preset difference to charge the energy storage battery.

8. The method according to claim 7, characterized in that The switchable boost-drop circuit includes an electrically connected boost-drop selection unit, an inductance unit and a switch unit, the boost-drop selection unit includes a first bidirectional switch and a second bidirectional switch, the common end of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection end of the first bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the first bidirectional switch is electrically connected to the third end of the switch unit; the common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively, the switch unit includes a first switch device and a second switch device, the first switch The control end of the switch device is used to input a first driving signal, the first end of the first switch device is electrically connected to the second end of the inductor unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic module and the negative electrode of the energy storage battery respectively; the control end of the second switch device is used to input a second driving signal, the first end of the second switch device is electrically connected to the second end of the inductor unit, and the second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit respectively. When the voltage of the photovoltaic module is less than the voltage of the energy storage battery, the charging voltage is increased based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery, including: In the case where the voltage of the photovoltaic assembly is lower than the voltage of the energy storage battery, the first path of the first bidirectional switch is controlled to be turned on and the second path of the first bidirectional switch is turned off, and the second path of the second bidirectional switch is controlled to be turned on and the first path of the second bidirectional switch is turned off, wherein the first path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the first selection end of the first bidirectional switch, the second path of the first bidirectional switch is a path between the common end of the first bidirectional switch and the second selection end of the first bidirectional switch, the first path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the first selection end of the second bidirectional switch, and the second path of the second bidirectional switch is a path between the common end of the second bidirectional switch and the second selection end of the second bidirectional switch; Controlling the first switch device to be turned on and the second switch device to be turned off, so that the charging current generated by the photovoltaic assembly passes through the first path of the first bidirectional switch, the inductor unit and the first switch device in sequence, so as to increase the charging voltage in the inductor unit until the target voltage difference is less than or equal to a preset difference; When the target voltage difference is less than or equal to the preset difference, the first switching device and the second switching device are both controlled to be cut off, so that the charging voltage in the inductor unit generates the charging current and passes through the freewheeling diode in the second switching device and the second path of the second bidirectional switch in sequence to charge the energy storage battery.

9. The method according to claim 8, characterized in that Controlling the first switch device to turn on includes: Setting a duty cycle of the first driving signal; generating the first driving signal according to the duty cycle; The first driving signal is input to the control terminal of the first switching device to control the first switching device to be turned on, wherein the duty cycle is proportional to the size of the charging current.

10. The method according to claim 7, characterized in that The switchable boost-drop circuit includes an electrically connected boost-drop selection unit, an inductance unit and a switch unit, the boost-drop selection unit includes a first bidirectional switch and a second bidirectional switch, the common end of the first bidirectional switch is electrically connected to the positive electrode of the photovoltaic component, the first selection end of the first bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the first bidirectional switch is electrically connected to the third end of the switch unit; the common end of the second bidirectional switch is electrically connected to the positive electrode of the energy storage battery, the first selection end of the second bidirectional switch is electrically connected to the first end of the inductance unit, and the second selection end of the second bidirectional switch is electrically connected to the second selection end of the first bidirectional switch and the third end of the switch unit respectively, the switch unit includes a first switch device and a second switch device, the control end of the first switch device The control end of the first switch device is used to input a first driving signal, the first end of the first switch device is electrically connected to the second end of the inductor unit, and the second end of the first switch device is electrically connected to the negative electrode of the photovoltaic module and the negative electrode of the energy storage battery respectively; the control end of the second switch device is used to input a second driving signal, the first end of the second switch device is electrically connected to the second end of the inductor unit, and the second end of the second switch device is electrically connected to the second selection end of the first bidirectional switch in the boost-drop selection unit and the second selection end of the second bidirectional switch in the boost-drop selection unit respectively. When the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, the charging voltage is reduced based on the photovoltaic module until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery, including: When the voltage of the photovoltaic module is greater than or equal to the voltage of the energy storage battery, the second path of the first bidirectional switch is controlled to be turned on and the first path of the first bidirectional switch is turned off, and the first path of the second bidirectional switch is controlled to be turned on and the second path of the second bidirectional switch is turned off; The first switch device is controlled to be turned off and the second switch device is controlled to be turned on, so that the charging current generated by the photovoltaic component passes through the second path of the first bidirectional switch, the second switch device and the inductor unit in sequence, so as to reduce the charging voltage based on the photovoltaic component until the target voltage difference is less than or equal to the preset difference, so as to charge the energy storage battery.

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