Energy storage apparatus, and photovoltaic power conversion system

Abstract

Provided are an energy storage apparatus (10) and a photovoltaic power conversion system. The energy storage apparatus (10) is applied to the photovoltaic power conversion system. The photovoltaic power conversion system comprises a photovoltaic assembly (20) and a photovoltaic inverter (30). The energy storage apparatus (10) comprises a control module (11), a bidirectional buck / boost module (12) and an energy storage module (13), wherein the bidirectional buck / boost module (12) is connected to the control module (11), and the bidirectional buck / boost module (12) is used for connecting to an output end of the photovoltaic assembly (20) and an input end of the photovoltaic inverter (30); the energy storage module (13) is connected to the bidirectional buck / boost module (12); and under the control of the control module (11), the bidirectional buck / boost module (12) is used for boosting or bucking an output voltage from the photovoltaic assembly (20), and then charging the energy storage module (13), or is used for boosting or bucking a discharge voltage from the energy storage module (13) when the energy storage module (13) discharges, and then transmitting the discharge voltage to the photovoltaic inverter (30). A circuit and system of the energy storage apparatus (10) can store redundant energy from the photovoltaic assembly (20), thereby effectively preventing the waste of energy from the photovoltaic assembly (20), and when the quantity of electricity provided by the photovoltaic assembly (20) is insufficient, the energy storage apparatus (10) can also supply power to a load (40).

Description

Energy storage device and photovoltaic energy storage inverter system Technical Field

[0001] The present application relates to the field of photovoltaic energy storage technology, and in particular to an energy storage device and a photovoltaic energy storage inverter system. Background Art

[0002] The photovoltaic inverter systems currently on the market include photovoltaic modules and photovoltaic inverters. The output end of the photovoltaic module is connected to the input end of the photovoltaic inverter. The output end of the photovoltaic inverter is used to connect to the load. The photovoltaic module is used to absorb solar energy from the sun and convert the solar energy into direct current and directly output it to the photovoltaic inverter. The photovoltaic inverter is used to convert the direct current output by the photovoltaic module into alternating current and output it to the load.

[0003] However, when the output power of photovoltaic modules exceeds the power demand of the load, the excess energy of the photovoltaic modules will flow into the grid, resulting in energy waste. Therefore, how to effectively utilize the excess energy of photovoltaic modules to avoid energy waste has become an urgent problem to be solved.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide an energy storage device and a photovoltaic energy storage inverter system including the same, which can solve the problem in the related art that when the output power of the photovoltaic module is greater than the required power of the load, the excess energy of the photovoltaic module will flow to the power grid, causing energy waste.

[0006] In a first aspect, an embodiment of the present application provides an energy storage device, which is used in a photovoltaic energy storage inverter system. The photovoltaic energy storage inverter system also includes interconnected photovoltaic modules and photovoltaic inverters; the energy storage device includes a control module, a bidirectional buck-boost module and an energy storage module, the bidirectional buck-boost module is connected to the control module, the bidirectional buck-boost module is used to connect to the output end of the photovoltaic module and the input end of the photovoltaic inverter, the energy storage module is connected to the bidirectional buck-boost module, the energy storage module is used to store and release electrical energy, and the bidirectional buck-boost module is controlled by the control module to boost or buck the output voltage of the photovoltaic module and then charge the energy storage module, or to boost or buck the discharge voltage of the energy storage module when the energy storage module is discharging and then transmit it to the photovoltaic inverter.

[0007] Based on the energy storage device of the embodiment of the present application, a control module, a bidirectional buck-boost module, and an energy storage module are designed. On the one hand, the control module controls the bidirectional buck-boost module to boost or buck the output voltage of the photovoltaic module and then charges the energy storage module, so as to store a portion of the energy output by the photovoltaic module in the energy storage module, thereby increasing the power of the energy storage module so that the energy storage device can supply power to the load. On the other hand, the control module controls the bidirectional buck-boost module to boost or buck the discharge voltage of the energy storage module when the energy storage module is discharged, and then transmits it to the photovoltaic inverter, so as to release the excess energy stored in the energy storage module and converted from the photovoltaic module to the load to continue to supply the load for normal operation.

[0008] In a second aspect, an embodiment of the present application provides a photovoltaic energy storage inverter system, which includes a photovoltaic module, a photovoltaic inverter and the above-mentioned energy storage device, wherein the photovoltaic module and the energy storage device are detachably connected, and the photovoltaic inverter and the energy storage device are detachably connected.

[0009] Based on the photovoltaic energy storage inverter system in the embodiment of the present application, the photovoltaic components, energy storage device and photovoltaic inverter are independent components. Users can move and assemble the photovoltaic components, energy storage device and photovoltaic inverter accordingly according to the actual application environment to meet the user's electricity needs in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0011] FIG1 is a schematic diagram of the framework structure of an energy storage device in one embodiment of the present application;

[0012] FIG2 is a schematic diagram of the framework structure of a photovoltaic energy storage inverter system in one embodiment of the present application;

[0013] FIG3 is a schematic diagram of the framework structure of a photovoltaic energy storage inverter system in the related art;

[0014] FIG4 is a schematic diagram of the framework structure of a photovoltaic energy storage inverter system in another embodiment of the present application;

[0015] FIG5 is a schematic diagram of the circuit structure of a bidirectional buck-boost module of an energy storage device in an embodiment of the present application.

[0016] Figure numerals: 10, energy storage device; 11, control module; 12, bidirectional buck-boost module; Q1, first switching element; Q2, second switching element; Q3, third switching element; Q4, fourth switching element; L, inductor; 13, energy storage module; 14, sampling module; 15, communication module; 20, photovoltaic module; 30, photovoltaic inverter; 40, load. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0018] 1-2 , a first aspect of the present application provides an energy storage device 10 , which can store excess energy of a photovoltaic assembly 20 to effectively avoid energy waste of the photovoltaic assembly 20 .

[0019] The energy storage device 10 is used in a photovoltaic energy storage inverter system, which also includes interconnected photovoltaic modules 20 and photovoltaic inverters 30. The energy storage device 10 includes a control module 11, a bidirectional buck-boost module 12, and an energy storage module 13. The bidirectional buck-boost module 12 is connected to the control module 11 and is used to connect to the output end of the photovoltaic module 20 and the input end of the photovoltaic inverter 30. The energy storage module 13 is connected to the bidirectional buck-boost module 12 and is used to store and release electrical energy. Under the control of the control module 11, the bidirectional buck-boost module 12 is used to boost or buck the output voltage of the photovoltaic module 20 and then charge the energy storage module 13, or to boost or buck the discharge voltage of the energy storage module 13 when the energy storage module 13 is discharging and then transmit it to the photovoltaic inverter 30.

[0020] The specific circuit structure of the energy storage device 10 is described below in conjunction with FIG. 1 to FIG. 5 .

[0021] As shown in Figures 1 and 2, the energy storage device 10 is used in a photovoltaic energy storage inverter system, which also includes a photovoltaic module 20 and a photovoltaic inverter 30. The photovoltaic module 20 absorbs solar energy from the sun and converts it into direct current (DC) for output. The photovoltaic inverter 30 converts the DC power output by the photovoltaic module 20 into alternating current (AC) and outputs it to a load. Specifically, the output of the photovoltaic module 20 is connected to the input of the photovoltaic inverter 30, and the output of the photovoltaic inverter 30 can be connected to a load 40. That is, the photovoltaic module 20 converts solar energy from the sun into DC power and outputs it to the photovoltaic inverter 30. The photovoltaic inverter 30 converts the DC power into AC power and outputs it to the load 40 to power the load 40. The "load 40" can be understood as any device that consumes electrical energy during operation. For example, the load 40 can include, but is not limited to, household appliances such as refrigerators and air conditioners. It should be noted that the energy storage device 10 can be connected to a single photovoltaic module 20 or to multiple photovoltaic modules 20 simultaneously.

[0022] As shown in FIG1-FIG2 , the energy storage device 10 includes a control module 11 , a bidirectional buck-boost module 12 and an energy storage module 13 .

[0023] The control module 11 serves as the core controller of the energy storage device 10. The control module 11 can obtain the output power of the photovoltaic component 20, and the control module 11 can also obtain the required power of the load 40. Among them, "required power" can be understood as the power required for the load 40 to work normally (such as the rated power of the load 40). The specific implementation method of the control module 11 obtaining the output power of the photovoltaic component 20 and the required power of the load 40 will be introduced in detail below. It should be noted that, depending on the specific form of the load 40 connected to the output end of the photovoltaic inverter 30, the size of the required power of the load 40 obtained by the control module 11 is also different. The control module 11 includes an MCU (Microcontroller Unit).

[0024] The bidirectional buck-boost module 12 is a functional module in the energy storage device 10 for controlling the charge and discharge process of the energy storage module 13 (described below). The specific circuit structure of the bidirectional buck-boost module 12 will be described in detail below.

[0025] The bidirectional buck-boost module 12 is connected to the control module 11 , and the bidirectional buck-boost module 12 is used to connect to the output end of the photovoltaic assembly 20 and the input end of the photovoltaic inverter 30 .

[0026] The energy storage module 13 serves as the power source of the energy storage device 10. It can release energy to the photovoltaic inverter 30 to power the load 40, and can also store energy released from the photovoltaic assembly 20. The energy storage module 13 includes a battery and a battery management chip, and the battery can be a storage battery or a lithium battery.

[0027] The energy storage module 13 is connected to the bidirectional buck-boost module 12 , that is, the energy storage module 13 can be connected to the output end of the photovoltaic assembly 20 and the input end of the photovoltaic inverter 30 via the bidirectional buck-boost module 12 .

[0028] Under the control of the control module 11 , the bidirectional buck-boost module 12 is used to boost or buck the output voltage of the photovoltaic assembly 20 and then charge the energy storage module 13 . At this time, the output power of the photovoltaic assembly 20 may be greater than the power demanded by the load 40. The control module 11 controls the bidirectional buck-boost module 12 to boost or buck the output voltage of the photovoltaic assembly 20, and stores the excess output power output by the photovoltaic assembly 20 (i.e., the output power remaining after meeting the power demand of the load 40) in the energy storage module 13, so that the photovoltaic assembly 20 can simultaneously supply power to the load 40 and the energy storage module 13 (i.e., the first working mode described below). Alternatively, the output end of the photovoltaic inverter 30 may not be connected to the load 40, or the output end of the photovoltaic inverter 30 may be connected to the load 40, but the load 40 has no power demand. The control module 11 controls the bidirectional buck-boost module 12 to boost or buck the output voltage of the photovoltaic assembly 20, and stores all the output power output by the photovoltaic assembly 20 in the energy storage module 13, so that the photovoltaic assembly 20 can supply power to the energy storage module 13 alone (i.e., the second working mode described below).

[0029] Under the control of the control module 11, the bidirectional buck-boost module 12 can also be used to boost or buck the discharge voltage of the energy storage module 13 during discharge, and then transmit it to the photovoltaic inverter 30. In this case, if the output power of the photovoltaic module 20 is less than the power required by the load 40, the control module 11 controls the bidirectional buck-boost module 12 to boost or buck the discharge voltage of the energy storage module 13 during discharge, releasing the energy of the energy storage module 13 to the photovoltaic inverter 30, enabling the energy storage module 13 to independently power the load 40 (i.e., the third operating mode described below). Alternatively, if the output power of the photovoltaic module 20 is less than the power required by the load 40, the control module 11 controls the bidirectional buck-boost module 12 to boost or buck the discharge voltage of the energy storage module 13 during discharge, releasing the energy of the energy storage module 13 to the photovoltaic inverter 30, and also releasing the output power of the photovoltaic module 20 to the photovoltaic inverter 30, enabling the energy storage module 13 and the photovoltaic module 20 to jointly power the load 40 (i.e., the fourth operating mode described below).

[0030] Of course, under the control of the control module 11, the bidirectional buck-boost module 12 can also allow the photovoltaic component 20 to supply power to the load 40 alone (that is, the fifth working mode introduced below). At this time, the bidirectional buck-boost module 12 does not involve the process of boosting or lowering the output voltage of the photovoltaic component 20, nor does it involve the process of boosting or lowering the discharge voltage of the energy storage module 13.

[0031] Based on the energy storage device 10 in the embodiment of the present application, a control module 11, a bidirectional buck-boost module 12 and an energy storage module 13 are designed; on the one hand, the control module 11 controls the bidirectional buck-boost module 12 to boost or buck the output voltage of the photovoltaic component 20 and then charges the energy storage module 13, so as to store the energy output by the photovoltaic component 20 in the energy storage module 13, increase the power of the energy storage module 13 so that the energy storage device 10 can supply power to the load 40; on the other hand, the control module 11 controls the bidirectional buck-boost module 12 to boost or buck the discharge voltage of the energy storage module 13 when the energy storage module 13 is discharging, and then transmit it to the photovoltaic inverter 30, so as to release the energy stored in the energy storage module 13 converted from the photovoltaic component 20 to the load 40 for normal operation of the load 40.

[0032] It is worth mentioning that the energy storage device 10 is directly connected to the output end of the photovoltaic module 20, and the excess DC power output by the photovoltaic module 20 is directly supplied to the energy storage module 13 through the bidirectional buck-boost module 12. Compared with the connection method shown in Figure 3 (at this time, the photovoltaic inverter converts the DC power output by the photovoltaic module into AC power, and then the excess AC power needs to be converted into DC power through the AC-DC converter and stored in the energy storage device), it can effectively reduce the energy loss of the excess energy output by the photovoltaic module 20 on the AC-DC converter in Figure 3, and the overall cost is lower.

[0033] Furthermore, as shown in Figure 2, the energy storage device 10 also includes a sampling module 14, which is used to be connected to the output end of the photovoltaic component 20 to sample the current or voltage of the photovoltaic component 20; the control module 11 is connected to the sampling module 14 and obtains the output power of the photovoltaic component 20 based on the current or voltage of the photovoltaic component 20 sampled by the sampling module 14. The control module 11 can also be used to obtain the required power of the load 40 connected to the photovoltaic inverter 30.

[0034] Considering that the control module 11 can compare the output power of the photovoltaic module 20 with the required power of the load 40 and control the different operating modes of the bidirectional buck-boost module 12 based on different comparison results to meet the charging and discharging requirements of the energy storage module 13 in different application scenarios, the operating modes of the bidirectional buck-boost module 12 include the following situations.

[0035] Charging process of energy storage module 13:

[0036] When the output power of the photovoltaic assembly 20 is greater than the power demanded by the load 40, the control module 11 controls the bidirectional buck-boost module 12 to be in the first working mode. In the first working mode, the bidirectional buck-boost module 12 is used to boost or buck the output voltage of the photovoltaic assembly 20 and then charge the energy storage module 13, so that the photovoltaic assembly 20 can supply power to the load 40 and the energy storage module 13 together. It should be noted that in the first working mode, part of the output power of the photovoltaic assembly 20 is provided to the load 40 to meet the power demand of the load 40, and the other part of the output power of the photovoltaic assembly 20 is provided to the energy storage module 13 to charge the energy storage module 13. In addition, the output power of the photovoltaic assembly 20 is distributed to meet the power demand of the load 40 first, and on the basis of meeting the power demand of the load 40, the remaining output power of the photovoltaic assembly 20 is used to charge the energy storage module 13 to ensure the normal operation of the load 40.

[0037] In this design, the control module 11 controls the bidirectional buck-boost module 12 to be in the first working mode, so that the photovoltaic component 20 can simultaneously power the load 40 and the energy storage module 13, which can not only meet the power demand of the load 40, but also use the remaining output power of the photovoltaic component 20 to charge the energy storage module 13; by designing the bidirectional buck-boost module 12, the power control of the photovoltaic inverter 30 can be achieved to maximize the matching of the output power of the photovoltaic inverter 30 with the power demand of the load 40, so as to achieve self-generation and self-use, and there is no efficiency loss in the part that supplies power to the photovoltaic inverter 30.

[0038] When the power demand of the load 40 obtained by the control module 11 is zero, the control module 11 controls the bidirectional buck-boost module 12 to enter the second operating mode. In the second operating mode, the bidirectional buck-boost module 12 is used to boost or buck the output voltage of the photovoltaic module 20 to charge the energy storage module 13, thereby ensuring that the photovoltaic module 20 only supplies power to the energy storage module 13. It should be noted that "the power demand of the load 40 obtained by the control module 11 is zero" can mean that the output of the photovoltaic inverter 30 is not connected to the load 40, or it can mean that the output of the photovoltaic inverter 30 is connected to the load 40, but the load 40 has no power demand. In addition, when the bidirectional buck-boost module 12 is in the second operating mode, the output power of the photovoltaic module 20 can be any value. For example, when the output power of the photovoltaic module 20 is high, in the second operating mode, the photovoltaic module 20 can charge the energy storage module 13 at a high charging power; when the output power of the photovoltaic module 20 is low, in the second operating mode, the photovoltaic module 20 can charge the energy storage module 13 at a low charging power.

[0039] In this design, when the photovoltaic inverter 30 is not connected to the load 40, or when the load 40 connected to the photovoltaic inverter 30 has no power demand, the control module 11 controls the bidirectional buck-boost module 12 to be in the second working mode, so that the photovoltaic assembly 20 only supplies power to the energy storage module 13, increasing the power of the energy storage module 13 so that the energy storage module 13 can supply power to the load 40 in other working modes.

[0040] The discharging process of the energy storage module 13 is as follows:

[0041] When the output power of the PV module 20 is less than the power demanded by the load 40, and if the output power of the PV module 20 obtained by the control module 11 is less than or equal to a preset first power threshold, the control module 11 controls the bidirectional buck-boost module 12 to operate in a third operating mode. In the third operating mode, the bidirectional buck-boost module 12 is configured to step up or down the discharge voltage of the energy storage module 13 during discharge, and then transmit the voltage to the PV inverter 30, thereby enabling the energy storage module 13 to supply power to the load 40, and the PV module 20 stops supplying power to the load 40. It should be noted that the "first power threshold" is a power value that can only meet the power loss caused by the internal resistance of the wire. For example, when the output power of the photovoltaic module 20 obtained by the control module 11 is exactly the first power threshold, the power generation of the photovoltaic module 20 is extremely low, so that the output power of the photovoltaic module 20 is completely lost in the internal resistance of the wire. Therefore, the photovoltaic module 20 will not supply power to the load 40. For another example, when the output power of the photovoltaic module 20 obtained by the control module 11 is exactly zero, the power generation of the photovoltaic module 20 is zero. Therefore, the photovoltaic module 20 will not supply power to the load 40. The specific value of the "first power threshold" is not limited here, and designers can pre-set it according to actual needs.

[0042] In this design, when the power generation of the photovoltaic component 20 is zero or extremely low, the control module 11 controls the bidirectional buck-boost module 12 to be in the third working mode, so that the energy storage module 13 can supply power to the load 40 alone to meet the power demand of the load 40; by designing the bidirectional buck-boost module 12, the power control of the photovoltaic inverter 30 can be achieved to maximize the matching of the output power of the photovoltaic inverter 30 with the required power of the load 40, so as to achieve self-generation and self-use, and there is no efficiency loss in the part that supplies power to the photovoltaic inverter 30.

[0043] When the output power of the photovoltaic assembly 20 is less than the power required by the load 40, if the output power of the photovoltaic assembly 20 obtained by the control module 11 is greater than the first power threshold and less than or equal to the preset second power threshold, the control module 11 controls the bidirectional buck-boost module 12 to enter the fourth operating mode. In the fourth operating mode, the bidirectional buck-boost module 12 is used to boost or buck the discharge voltage of the energy storage module 13 during discharge, and then transmit it to the photovoltaic inverter 30, so that the photovoltaic assembly 20 and the energy storage module 13 jointly power the load 40. It should be noted that the "second power threshold" is a power value that is insufficient for the photovoltaic assembly 20 to independently power the load 40 to ensure that the load 40 can operate. For example, when the output power of the photovoltaic assembly 20 obtained by the control module 11 is exactly the second power threshold, the power generated by the photovoltaic assembly 20 is low and insufficient to enable the load 40 to operate. Therefore, the photovoltaic assembly 20 needs to cooperate with the energy storage module 13 to power the load 40 to meet the power demand of the load 40. There is no limitation on the specific value of the "second power threshold" here, and designers can pre-set it according to actual needs.

[0044] In this design, when the power generation of the photovoltaic component 20 is too low to allow the load 40 to operate, the control module 11 controls the bidirectional buck-boost module 12 to be in the fourth operating mode, so that the energy storage module 13 can cooperate with the photovoltaic component 20 to supply power to the load 40 to meet the power demand of the load 40.

[0045] Regarding the process in which the energy storage module 13 is neither charged nor discharged:

[0046] When the output power of PV panel 20 is less than the power demanded by load 40, and the output power of PV panel 20 obtained by control module 11 is greater than a second power threshold, control module 11 controls bidirectional buck-boost module 12 to operate in the fifth operating mode. In the fifth operating mode, bidirectional buck-boost module 12 does not operate, allowing PV panel 20 to directly power load 40.

[0047] In this design, when the power generation of the photovoltaic component 20 is low but the load 40 can still work, the control module 11 controls the bidirectional buck-boost module 12 to be in the fifth working mode, so that the photovoltaic component 20 can supply power to the load 40 alone to meet the power demand of the load 40; in the fifth working mode, the photovoltaic component 20 directly supplies power to the load 40 without passing through any other conversion module in the middle, and there is almost no power loss.

[0048] As shown in FIG4 , considering that the control module 11 is capable of obtaining the power demand of the load 40, comparing the power demand of the load 40 with the output power of the photovoltaic module 20, and controlling the bidirectional buck-boost module 12 to operate in one of the first, second, third, fourth, and fifth operating modes described above based on different comparison results, in order to enable the control module 11 to obtain the power demand of the load 40, in some embodiments, the energy storage device 10 further includes a communication module 15, which is connected to the control module 11 and is configured to obtain the power demand of the load 40 after establishing a communication connection with the load 40. The communication module 15 can be a communication interface electrically connected to the control module 11 and integrated into the energy storage device 10. In this case, the user can connect an electric meter / smart socket to the communication interface, and the control module 11 can obtain the power demand of the load 40 through the electric meter / smart socket. The communication module 15 can also be a Wi-Fi module or a Bluetooth module electrically connected to the control module 11. In this case, the control module 11 can obtain the power demand of the load 40 through, for example, cloud communication.

[0049] As shown in FIG5 , considering that in different operating modes, the bidirectional buck-boost module 12 can boost or buck the output voltage of the photovoltaic module 20 to charge the energy storage module 13, or, when the energy storage module 13 is discharging, boost or buck the discharge voltage of the energy storage module 13 to transmit it to the photovoltaic inverter 30. To enable the bidirectional buck-boost module 12 to have the corresponding functions, the bidirectional buck-boost module 12 includes a DC-DC bidirectional buck-boost circuit. Specifically, the bidirectional buck-boost circuit includes a first switching element Q1, a second switching element Q2, a third switching element Q3, a fourth switching element Q4 and an inductor L; the first connection end of the first switching element Q1 is used to connect to the output end of the photovoltaic component 20; the first connection end of the second switching element Q2 is connected to the second connection end of the first switching element Q1, and the second connection end of the second switching element Q2 is grounded; the first end of the inductor L is connected to the second connection end of the first switching element Q1; the first connection end of the third switching element Q3 is connected to the second end of the inductor L, and the second connection end of the third switching element Q3 is connected to the energy storage module 13; the first connection end of the fourth switching element Q4 is connected to the second end of the inductor L, and the second connection end of the fourth switching element Q4 is grounded; wherein, the control module 11 is connected to the first switching element Q1, the second switching element Q2, the third switching element Q3 and the fourth switching element Q4 to control the on and off states of the first switching element Q1, the second switching element Q2, the third switching element Q3 and the fourth switching element Q4.

[0050] It should be noted that the specific form of at least one of the first switch element Q1, the second switch element Q2, the third switch element Q3 and the fourth switch element Q4 can be at least one of an electrically controlled single-pole single-throw switch, a transistor or a field-effect transistor. The above-mentioned “on-off state” includes an “on state” and an “off state”. The first switch element Q1 / the second switch element Q2 / the third switch element Q3 / the fourth switch element Q4 all have an on-off state. Taking the first switch element Q1 as an example, for example, when the first switch element Q1 is specifically in the form of an electrically controlled single-pole single-throw switch, the “on state” of the electrically controlled single-pole single-throw switch is a state when the movable end of the electrically controlled single-pole single-throw switch is closed, and conversely, the “off state” of the electrically controlled single-pole single-throw switch is a state when the movable end of the electrically controlled single-pole single-throw switch is disconnected; when the first switch element Q1 is specifically in the form of a transistor, the “on state” of the transistor is a state when the collector and emitter of the transistor are connected, and conversely, the “off state” of the transistor is a state when the collector and emitter of the transistor are disconnected.

[0051] As shown in FIG5 , the specific on-off conditions of the first switch element Q1 , the second switch element Q2 , the third switch element Q3 and the fourth switch element Q4 are described below in combination with the above five working modes of the bidirectional buck-boost module 12 .

[0052] When the bidirectional buck-boost module 12 is in the first operating mode described above, if the output voltage of the photovoltaic module 20 is greater than the charging voltage of the energy storage module 13, the third switch element Q3 is turned on, the fourth switch element Q4 is turned off, and the first switch element Q1, the second switch element Q2, and the inductor L form a buck circuit; if the output voltage of the photovoltaic module 20 is less than the charging voltage of the energy storage module 13, the first switch element Q1 is turned on, the second switch element Q2 is turned off, and the third switch element Q3, the fourth switch element Q4, and the inductor L form a boost circuit.

[0053] When the bidirectional buck-boost module 12 is in the second operating mode, if the output voltage of the photovoltaic module 20 is greater than the charging voltage of the energy storage module 13, the third switch element Q3 is turned on, the fourth switch element Q4 is turned off, and the first switch element Q1, the second switch element Q2, and the inductor L form a buck circuit; if the output voltage of the photovoltaic module 20 is less than the charging voltage of the energy storage module 13, the first switch element Q1 is turned on, the second switch element Q2 is turned off, and the third switch element Q3, the fourth switch element Q4, and the inductor L form a boost circuit.

[0054] When the bidirectional buck-boost module 12 is in the third operating mode, if the input voltage of the photovoltaic inverter 30 is greater than the discharge voltage of the energy storage module 13, the third switch element Q3 is turned on, the fourth switch element Q4 is turned off, and the first switch element Q1, the second switch element Q2, and the inductor L form a boost circuit. If the input voltage of the photovoltaic inverter 30 is less than the discharge voltage of the energy storage module 13, the first switch element Q1 is turned on, the second switch element Q2 is turned off, and the third switch element Q3, the fourth switch element Q4, and the inductor L form a buck circuit.

[0055] When the bidirectional buck-boost module 12 is in the fourth operating mode, if the output voltage of the photovoltaic module 20 is greater than the discharge voltage of the energy storage module 13, the third switch element Q3 is turned on, the fourth switch element Q4 is turned off, and the first switch element Q1, the second switch element Q2, and the inductor L form a boost circuit; if the output voltage of the photovoltaic module 20 is less than the discharge voltage of the energy storage module 13, the first switch element Q1 is turned on, the second switch element Q2 is turned off, and the third switch element Q3, the fourth switch element Q4, and the inductor L form a buck circuit.

[0056] When the bidirectional buck-boost module 12 is in the fifth operating mode, the first switch element Q1 , the second switch element Q2 , the third switch element Q3 and the fourth switch element Q4 are all turned off.

[0057] The second aspect of the present application proposes a photovoltaic energy storage inverter system, which includes a photovoltaic module 20, a photovoltaic inverter 30, and the aforementioned energy storage device 10. The photovoltaic module 20 and the energy storage device 10 are detachably connected, and the photovoltaic inverter 30 and the energy storage device 10 are detachably connected. In this design, the photovoltaic energy storage inverter system with the aforementioned energy storage device 10 allows users to move and assemble the photovoltaic module 20, the energy storage device 10, and the photovoltaic inverter 30 according to the actual application environment to meet the user's electricity needs in different application scenarios.

[0058] It should be noted that in this photovoltaic energy storage inverter system, the photovoltaic assembly 20, the energy storage device 10 and the photovoltaic inverter 30 are independent components. The user can assemble the photovoltaic assembly 20, the energy storage device 10 and the photovoltaic inverter 30 accordingly according to the actual application environment. For example, in an application environment on a cloudy day, the user can only assemble the photovoltaic inverter 30 and the energy storage device 10 together to meet the power supply requirements of the energy storage device 10 to the load 40. For another example, in an application environment on a sunny day, the user can only assemble the photovoltaic assembly 20 and the energy storage device 10 together to meet the power supply requirements of the photovoltaic assembly 20 to the energy storage device 10; of course, the user can also assemble the photovoltaic assembly 20, the energy storage device 10 and the photovoltaic inverter 30 together according to actual needs to meet the power supply requirements of the photovoltaic assembly 20 and / or the energy storage device 10 to the load 40.

[0059] The energy storage device 10 can also be a portable outdoor mobile energy storage device, so that after charging the energy storage device 10 through the photovoltaic module 20, the user can take the energy storage device 10 to use outdoors, which not only efficiently utilizes the excess electrical energy converted by the photovoltaic module 20, but also makes it convenient for the user to obtain sufficient electrical energy outdoors to power the load 40.

[0060] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "upper", "lower", "left", "right", etc. indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the drawings. This is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as a limitation on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0061] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An energy storage device for a photovoltaic energy storage inverter system, wherein the photovoltaic energy storage inverter system further comprises interconnected photovoltaic modules and photovoltaic inverters; characterized in that: The energy storage device comprises: Control module; a bidirectional buck-boost module, connected to the control module and used to be connected to the output end of the photovoltaic module and the input end of the photovoltaic inverter; and An energy storage module, connected to the bidirectional buck-boost module, for storing and releasing electric energy; Among them, the bidirectional buck-boost module is used, under the control of the control module, to boost or buck the output voltage of the photovoltaic component and then charge the energy storage module, or to boost or buck the discharge voltage of the energy storage module when the energy storage module is discharging and then transmit it to the photovoltaic inverter.

2. The energy storage device according to claim 1, characterized in that The energy storage device further includes a sampling module, which is used to be connected to the output end of the photovoltaic component to sample the current or voltage of the photovoltaic component; the control module is connected to the sampling module and obtains the output power of the photovoltaic component according to the current or voltage of the photovoltaic component sampled by the sampling module, and the control module is also used to obtain the required power of the load connected to the photovoltaic inverter; Among them, when the output power of the photovoltaic component is greater than the required power of the load, the control module controls the bidirectional buck-boost module to be in the first working mode. In the first working mode, the bidirectional buck-boost module is used to boost or buck the output voltage of the photovoltaic component and then charge the energy storage module, so that the photovoltaic component can supply power to the load and the energy storage module together.

3. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a sampling module, which is used to be connected to the output end of the photovoltaic component to sample the current or voltage of the photovoltaic component; the control module is connected to the sampling module The control module is further used to obtain the required power of the load connected to the photovoltaic inverter; and Among them, when the required power of the load obtained by the control module is zero, the control module controls the bidirectional buck-boost module to be in the second working mode. In the second working mode, the bidirectional buck-boost module is used to boost or buck the output voltage of the photovoltaic component and then charge the energy storage module, so that the photovoltaic component only supplies power to the energy storage module.

4. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a sampling module, which is used to be connected to the output end of the photovoltaic assembly to sample the current or voltage of the photovoltaic assembly; the control module is connected to the sampling module and obtains the output power of the photovoltaic assembly according to the current or voltage of the photovoltaic assembly obtained by the sampling module, and the control module is also used to obtain the required power of the load connected to the photovoltaic inverter; Among them, when the output power of the photovoltaic component is less than the required power of the load, if the output power of the photovoltaic component obtained by the control module is less than or equal to the preset first power threshold, the control module controls the bidirectional buck-boost module to be in a third working mode. In the third working mode, the bidirectional buck-boost module is used to boost or buck the discharge voltage of the energy storage module when the energy storage module is discharging, and then transmit it to the photovoltaic inverter, so that the energy storage module supplies power to the load, and the photovoltaic component stops supplying power to the load.

5. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a sampling module, which is used to be connected to the output end of the photovoltaic assembly to sample the current or voltage of the photovoltaic assembly; the control module is connected to the sampling module and obtains the output power of the photovoltaic assembly according to the current or voltage of the photovoltaic assembly obtained by the sampling module, and the control module is also used to obtain the required power of the load connected to the photovoltaic inverter; Among them, when the output power of the photovoltaic component is less than the required power of the load, if the output power of the photovoltaic component obtained by the control module is greater than a preset first power threshold and less than or equal to a preset second power threshold, the control module controls the bidirectional buck-boost module to be in a fourth working mode. In the fourth working mode, the bidirectional buck-boost module is used to boost or step down the discharge voltage of the energy storage module when the energy storage module is discharging, and then transmit it to the photovoltaic inverter, so that the photovoltaic component and the energy storage module jointly power the load.

6. The energy storage device according to claim 1, characterized in that: The energy storage device further includes a sampling module, which is used to be connected to the output end of the photovoltaic assembly to sample the current or voltage of the photovoltaic assembly; the control module is connected to the sampling module and obtains the output power of the photovoltaic assembly according to the current or voltage of the photovoltaic assembly obtained by the sampling module, and the control module is also used to obtain the required power of the load connected to the photovoltaic inverter; Among them, when the output power of the photovoltaic component is less than the required power of the load, if the output power of the photovoltaic component obtained by the control module is greater than the preset second power threshold, the control module controls the bidirectional buck-boost module to be in the fifth working mode. In the fifth working mode, the bidirectional buck-boost module does not work, so that the photovoltaic component directly supplies power to the load.

7. The energy storage device according to any one of claims 2 to 6, characterized in that: The energy storage device further includes a communication module, which is connected to the control module and is used to obtain the required power of the load after establishing a communication connection with the load.

8. The energy storage device according to any one of claims 1 to 6, characterized in that: The bidirectional buck-boost module includes a DC-DC bidirectional buck-boost circuit, and the DC-DC bidirectional buck-boost circuit includes: a first switch element, wherein a first connection end of the first switch element is used to be connected to an output end of the photovoltaic component; a second switching element, wherein a first connection terminal of the second switching element is connected to a first connection terminal of the first switching element The second connection end of the second switch element is connected to the ground, and the second connection end of the second switch element is grounded; an inductor, a first end of the inductor being connected to a second connection end of the first switch element; a third switch element, wherein a first connection end of the third switch element is connected to the second end of the inductor, and a second connection end of the third switch element is connected to the energy storage module; a fourth switch element, wherein a first connection end of the fourth switch element is connected to the second end of the inductor, and a second connection end of the fourth switch element is grounded; The control module is connected to the first switch element, the second switch element, the third switch element and the fourth switch element to control the on and off states of the first switch element, the second switch element, the third switch element and the fourth switch element.

9. The energy storage device according to claim 8, characterized in that: The bidirectional buck-boost module has a first working mode, a second working mode, a third working mode, a fourth working mode and a fifth working mode; In the first working mode, if the output voltage of the photovoltaic component is greater than the charging voltage of the energy storage module, the control module controls the third switch element to be turned on and the fourth switch element to be turned off, and the first switch element, the second switch element and the inductor constitute a step-down circuit; if the output voltage of the photovoltaic component is less than the charging voltage of the energy storage module, the control module controls the first switch element to be turned on and the second switch element to be turned off, and the third switch element, the fourth switch element and the inductor constitute a step-up circuit; and / or In the second working mode, if the output voltage of the photovoltaic component is greater than the charging voltage of the energy storage module, the control module controls the third switch element to be turned on and the fourth switch element to be turned off, and the first switch element, the second switch element and the inductor constitute a step-down circuit; if the output voltage of the photovoltaic component is less than the charging voltage of the energy storage module, the control module controls the first switch element to be turned on and the second switch element to be turned off, and the third switch element, the fourth switch element and the inductor constitute a step-up circuit; and / or In the third working mode, if the input voltage of the photovoltaic inverter is greater than the discharge voltage of the energy storage module, the control module controls the third switch element to be turned on and the fourth switch element to be turned off. If the input voltage of the photovoltaic inverter is lower than the discharge voltage of the energy storage module, the control module controls the first switch element to be turned on, the second switch element to be turned off, and the third switch element, the fourth switch element and the inductor to form a step-down circuit; and / or In the fourth working mode, if the output voltage of the photovoltaic module is greater than the discharge voltage of the energy storage module, the control module controls the third switch element to be turned on and the fourth switch element to be turned off, and the first switch element, the second switch element and the inductor form a boost circuit; if the output voltage of the photovoltaic module is less than the discharge voltage of the energy storage module, the control module controls the first switch element to be turned on and the second switch element to be turned off, and the third switch element, the fourth switch element and the inductor form a step-down circuit; and / or In the fifth working mode, the control module controls the first switch element, the second switch element, the third switch element, and the fourth switch element to be turned off.

10. A photovoltaic energy storage inverter system, characterized in that: include: The energy storage device as claimed in claim 1; A photovoltaic module, detachably connected to the energy storage device; A photovoltaic inverter is detachably connected to the energy storage device.

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