Switchable circuit, inverter circuit, energy storage device and photovoltaic system

Abstract

A switchable circuit, an inverter circuit, an energy storage device and a photovoltaic system, the switchable circuit comprises a first branch and a second branch, a first end of the first branch and a first end of the second branch are used for connecting a photovoltaic module, and a second end of the first branch and a second end of the second branch are used for connecting a first end of an inverter; the second branch circuit is provided with a DC / DC converter, and the second branch circuit is used for being connected with a battery; when the switchable circuit is in a first switching state, the first branch circuit is conducted, and the photovoltaic module is configured to supply power to the inverter through the first branch circuit. According to the application, when the switchable circuit is in the first switching state, the first branch is conducted, and the photovoltaic module can directly supply power to the inverter through the first branch, so that the DC / DC converter can be prevented from influencing the direct utilization efficiency of photovoltaic power generation, and the direct utilization efficiency of photovoltaic power generation is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, more particularly to a switchable circuit, an inverter circuit, an energy storage device and a photovoltaic system. BACKGROUND

[0002] The traditional photovoltaic inverter mode is to connect multiple photovoltaic panels in series and parallel, and then convert the direct current generated by the photovoltaic panels into alternating current through an inverter to access the power grid. The micro inverter inverts each photovoltaic panel separately, which has the advantages of independent MPPT (Maximum Power Point Tracking) control for each photovoltaic component, greatly improving overall efficiency, and avoiding the problems of direct current high voltage, poor weak light effect, and barrel effect in the traditional inverter mode.

[0003] The existing technical solution proposes to connect an energy storage battery to the micro inverter system to form a micro energy storage system, which can not only realize self-generation and self-use of photovoltaic power generation, but also store excess energy in the battery system to realize peak load shifting and maximize the economic benefits of electricity use.

[0004] However, the existing technical solution adds a DC / DC converter to realize MPPT function and charge the battery based on the original micro inverter, which reduces the direct utilization efficiency of photovoltaic power generation due to the addition of a DC / DC converter. SUMMARY

[0005] To solve at least one of the above problems, the present application is proposed. According to one aspect of the present application, a switchable circuit is provided, which includes: a first branch and a second branch, a first end of the first branch and a first end of the second branch are used to connect a photovoltaic component, a second end of the first branch and a second end of the second branch are used to connect an inverter; a DC / DC converter is arranged on the second branch, and the second branch is used to connect a battery; when the switchable circuit is in a first switching state, the first branch is turned on, and the photovoltaic component is configured to supply power to the inverter through the first branch.

[0006] In one embodiment of the present application, when the switchable circuit is in a second switching state, the second branch is turned on, and when the second branch is turned on, the photovoltaic component is configured to supply power to the inverter through the second branch; and / or when the second branch is turned on, the photovoltaic component is configured to supply power to the battery through the second branch.

[0007] In one embodiment of the present application, when the switchable circuit is in the second switching state, the second branch is turned on, and the inverter is further configured to be electrically connected to the battery through the second branch, and when the second branch is turned on, the battery is configured to supply power to the inverter through the second branch.

[0008] In one embodiment of the present application, a switching device is arranged on the switchable circuit, when the switching device is in the first switching state, the switchable circuit is in the first switching state, and when the switching device is in the second switching state, the switchable circuit is in the second switching state.

[0009] In one embodiment of the present application, the switching device includes a switching switch, and the switchable circuit further includes a main circuit, the switching switch is arranged at a first end of the main circuit, a second end of the main circuit is configured to be connected to the inverter, and the switching switch includes a switching part, when the first switching state is in, the first end of the main circuit is connected to the second end of the first branch through the switching part, and when the second switching state is in, the first end of the main circuit is connected to the second end of the second branch through the switching part.

[0010] In one embodiment of the present application, the switching device includes a first switch tube and a second switch tube, the first switch tube is arranged on the first branch, and the second switch tube is arranged on the second branch, when the first switching state is in, the first switch tube is turned on and the second switch tube is turned off, and when the second switching state is in, the second switch tube is turned on and the first switch tube is turned off.

[0011] In one embodiment of the present application, the switching device includes a first switch tube and a second switch tube, the first switch tube is arranged on the first branch, and the second switch tube is arranged on the second branch, when the first switching state is in, the first switch tube is turned on and the second switch tube is turned off, and when the second switching state is in, the second switch tube is turned on and the first switch tube is turned off.

[0012] In one embodiment of the present application, when the first switch tube and the second switch tube are both turned on, the photovoltaic module is further configured to supply power to the battery through the second branch; or when the second switch tube is turned on, the photovoltaic module is configured to supply power to the battery through the second branch.

[0013] In an embodiment of the present application, the inverter is further configured to connect with the battery through the first branch and the second branch, and the battery is configured to supply power to the inverter through the second branch and the first branch when the first switch tube is turned on.

[0014] In another aspect of the present application, an inverter circuit is provided, comprising an inverter and the switchable circuit according to any one of the above.

[0015] In an embodiment of the present application, a plurality of the switchable circuits are provided, and the first end of each of the switchable circuits is configured to connect with a photovoltaic module, the second end of at least two of the switchable circuits is connected with the same inverter, and the second end of at least two of the switchable circuits is further configured to connect with the same battery.

[0016] In another aspect of the present application, an energy storage device is provided, comprising a battery and the inverter circuit according to any one of the above, and the battery is connected with the switchable circuit in the inverter circuit.

[0017] In another aspect of the present application, a photovoltaic system is provided, comprising a photovoltaic module and the energy storage device according to the above, and the photovoltaic module is connected with the switchable circuit in the inverter circuit.

[0018] According to the switchable circuit, the inverter circuit, the energy storage device and the photovoltaic system of the embodiments of the present application, when the switchable circuit is in the first switching state and the first branch is turned on, the photovoltaic module can directly supply power to the inverter through the first branch, thereby improving the direct utilization efficiency of photovoltaic power generation. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. The drawings provided herein are for illustrative purposes only and, therefore, are not to be construed as being prior art to the present application. In the drawings, like reference numerals refer to like elements or steps throughout.

[0020] Figure 1 A structural schematic diagram of a micro energy storage system in the prior art is shown.

[0021] Figure 2 A structural block diagram of a switchable circuit according to an embodiment of the present application is shown.

[0022] Figure 3 A structural schematic diagram of an energy storage device according to an embodiment of the present application is shown.

[0023] Figure 4 A current flow direction diagram of a switchable circuit in an energy storage device according to an embodiment of the present application is shown.

[0024] Figure 5 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0025] Figure 6 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0026] Figure 7 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0027] Figure 8 A structural schematic diagram of an energy storage device according to an embodiment of the application is shown.

[0028] Figure 9 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0029] Figure 10 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0030] Figure 11 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0031] Figure 12 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0032] Figure 13 A structural schematic diagram of an energy storage device according to an embodiment of the application is shown.

[0033] Figure 14 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0034] Figure 15 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0035] Figure 16 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0036] Figure 17 A current flow diagram of a switchable circuit in an energy storage device according to an embodiment of the application is shown.

[0037] Figure 18 A structural block diagram of an inverter circuit according to an embodiment of the application is shown. DETAILED DESCRIPTION

[0038] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present application. However, it will be apparent to one of skill in the art upon

[0039] It should be understood that the present application can be carried out in many different forms without necessarily departing from the spirit or scope of the application. Rather, these examples are given so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. In the drawings, the sizes and relative sizes of layers and regions can be exaggerated for clarity. Like numbers refer to like elements throughout.

[0040] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers present. It will also be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0041] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0042] In the prior art, as Figure 1The micro energy storage system shown by connecting the energy storage battery to the micro inverter system comprises a DC / DC converter, a micro inverter and a battery, wherein the DC / DC converter realizes MPPT function for the photovoltaic module to charge the battery, and the micro inverter can invert the electricity generated by the photovoltaic module and the electricity stored in the battery into alternating current for the user.

[0043] The above technical solution has at least the following disadvantages:

[0044] The direct utilization efficiency of photovoltaic power generation is reduced due to the addition of a DC / DC converter;

[0045] Since the micro inverter also has MPPT function, when the battery is disconnected from the bus due to overcharging, the DC / DC converter and the micro inverter will work in MPPT state at the same time, which will cause instability of the system.

[0046] Therefore, in view of the foregoing technical problems, the present application provides a switchable circuit, comprising: a first branch and a second branch, a first end of the first branch and a first end of the second branch are used to connect a photovoltaic module, a second end of the first branch and a second end of the second branch are used to connect an inverter; a DC / DC converter is arranged on the second branch, and the second branch is used to connect a battery; when the switchable circuit is in a first switching state, the first branch is turned on, and the photovoltaic module is configured to supply power to the inverter through the first branch.

[0047] According to the switchable circuit of the present application, when the switchable circuit is in the first switching state, the first branch is turned on, and the photovoltaic module can directly supply power to the inverter through the first branch, thereby avoiding the influence of the DC / DC converter on the direct utilization efficiency of photovoltaic power generation and improving the direct utilization efficiency of photovoltaic power generation.

[0048] Moreover, after the battery is fully charged, by making the switchable circuit in the first switching state to turn on the first branch, the problem that when the battery is disconnected from the bus due to overcharging, the DC / DC converter and the inverter work in MPPT state at the same time, which will cause instability of the system, can be avoided.

[0049] In addition, by designing the switchable circuit to comprise the first branch and the second branch, when one of the branches fails, it will not affect the normal work of the other branch, thereby improving the stability of the system.

[0050] In order to thoroughly understand the present application, detailed structures will be proposed in the following description in order to illustrate the technical solutions proposed by the present application. The preferred embodiments of the present application are described in detail as follows, however, in addition to these detailed descriptions, the present application can also have other implementation manners.

[0051] The following will be described with reference to Figures 2-17A switchable circuit 110 according to an embodiment of the present application is described. As shown in Figure 2 The switchable circuit 110 includes a first branch 111 and a second branch 112, a first end of the first branch 111 and a first end of the second branch 112 are configured to be connected to a photovoltaic module, and a second end of the first branch 111 and a second end of the second branch 112 are configured to be connected to an inverter 120. A DC / DC converter 1121 is arranged on the second branch 112, and the second branch 112 is configured to be connected to a battery. When the switchable circuit 110 is in a first switching state, the first branch 111 is turned on, and the photovoltaic module is configured to supply power to the inverter 120 through the first branch 111.

[0052] Based on this, the present application provides a switchable circuit 110 capable of improving the direct utilization efficiency of photovoltaic power generation. According to the switchable circuit 110 of the present application, when the switchable circuit 110 is in the first switching state, the first branch 111 is turned on, and the photovoltaic module can directly supply power to the inverter 120 through the first branch 111, thereby avoiding the DC / DC converter 1121 affecting the direct utilization efficiency of photovoltaic power generation and improving the direct utilization efficiency of photovoltaic power generation.

[0053] Moreover, after the battery is fully charged, by making the switchable circuit 110 in the first switching state to turn on the first branch 111, the problem that when the battery is disconnected from the bus due to overcharging, the DC / DC converter 1121 and the inverter 120 work in the MPPT state at the same time, causing the system to be unstable, can be avoided.

[0054] In addition, by designing the switchable circuit 110 to include the first branch 111 and the second branch 112, when one of the branches fails, the other branch can still work normally, thereby improving the stability of the system.

[0055] It is worth noting that the connection relationship described in the present application is generally an electrical connection.

[0056] In one example, the inverter 120 can include a DC / DC converter and a DC / AC converter.

[0057] In one example, when the switchable circuit 110 is in a second switching state, the second branch 112 is turned on.

[0058] Illustratively, when the second branch 112 is turned on, the photovoltaic module can supply power to the inverter 120 through the second branch 112. In this case, the electrical energy generated by the photovoltaic module is converted in voltage by the DC / DC converter 1121 on the second branch 112 and then provided to the inverter 120, and then the inverter 120 inverts the electrical energy into alternating current for use by the user.

[0059] For example, when the second branch 112 is turned on, the photovoltaic module can supply power to the battery through the second branch 112. In this case, the electrical energy generated by the photovoltaic module is converted in voltage by the DC / DC converter 1121 on the second branch 112 and then provided to the battery, and then the electrical energy is inverted into alternating current by the inverter 120 for use by the user.

[0060] For example, the inverter 120 can also be connected to the battery through the second branch 112, and when the second branch 112 is turned on, the battery can supply power to the inverter 120 through the second branch 112. In this case, the battery can provide the electrical energy stored in its internal to the inverter 120, and then the electrical energy is inverted into alternating current by the inverter 120 for use by the user.

[0061] It should be noted that in the above power supply mode in which the second branch 112 is turned on, each power supply mode can exist alone or multiple power supply modes can exist simultaneously, which is not limited. For example, when the battery energy storage is not full, the electrical energy emitted by the photovoltaic module can be provided to the inverter 120 and the battery through the second branch 112; when the battery energy storage is full, the electrical energy emitted by the photovoltaic module through the second branch 112 can be provided only to the inverter 120, and not to the battery.

[0062] In one example, the switchable circuit 110 is provided with a switching device, and when the switching device is in a first switching state, the switchable circuit 110 is in a first switching state, and when the switching device is in a second switching state, the switchable circuit 110 is in a second switching state.

[0063] That is, the switchable circuit 110 can be switched between the first switching state and the second switching state by the switching state of the switching device, so that the first branch 111 is turned on and / or the second branch 112 is turned on. Of course, in addition to providing a switching device on the switchable circuit 110, the present application also does not exclude other measures that can achieve switching of the switchable circuit 110 between the first switching state and the second switching state.

[0064] In one example, the switching device includes a switching switch, and the switchable circuit 110 further includes a main circuit, the switching switch is arranged at a first end of the main circuit, a second end of the main circuit is used to connect the inverter 120, the switching switch includes a switching part, in the first switching state, the first end of the main circuit is connected to the second end of the first branch 111 through the switching part, and in the second switching state, the first end of the main circuit is connected to the second end of the second branch 112 through the switching part.

[0065] For example, as shown in FIG. 1, the switchable circuit 110 includes a main circuit 1102 and a switching switch 1101, and the switching switch 1101 is arranged at a first end of the main circuit 1102. The second end of the main circuit 1102 is used to connect the inverter 120, and the switching switch 1101 includes a switching part 1103. Figure 3As shown, the first end of the switchable circuit 110 is connected to the positive pole PV1+ and the negative pole PV1- of the photovoltaic module, the second end of the switchable circuit 110 is connected to the first end of the inverter I1, and the second end of the inverter I1 is connected to the positive pole ACL (AC live wire) and the negative pole ACN (AC neutral wire) of the load; the switchable circuit 110 includes a first branch 111, a second branch 112 and a main circuit (in the figure, the first end of the first branch 111 and the first end of the second branch 112 are connected to the same node and then connected to the positive pole PV1+ of the photovoltaic module), the main circuit is provided with a switch K1, and the second branch 112 is provided with a DC / DC converter D11; the second branch 112 is connected to the battery B1, and the first end of the inverter I1 is also connected to the battery B1 through the second branch 112.

[0066] like Figure 4 As shown, when the switching portion of the switch K1 is connected to the first branch 111, the switch K1 is in the first switching state. At this time, the first branch 111 is conductive and the second branch 112 is disconnected. The photovoltaic module is electrically connected to the inverter I1 through the first branch 111. The electrical energy generated by the photovoltaic module can be directly provided to the inverter I1 through the first branch 111 and the main circuit. The inverter I1 then inverts the electrical energy into AC power for use by the load. The direction of the electrical energy flow can be shown by the arrows in the figure. This power supply mode belongs to the photovoltaic power generation direct mode, which is to supply the electrical energy generated by the photovoltaic module only to the inverter I1 and not to the battery B1. For example, it can be used in conditions such as battery B1 failure or battery B1 being fully charged.

[0067] like Figure 5 As shown, when the switching portion of switch K1 is connected to second branch 112, switch K1 is in the second switching state. At this time, second branch 112 is conductive and first branch 111 is disconnected. The photovoltaic module is electrically connected to both inverter I1 and battery B1 via second branch 112. If battery B1 is not fully charged at this time, the electrical energy generated by the photovoltaic module undergoes voltage conversion via DC / DC converter D11 on second branch 112. This energy can be supplied to inverter I1 through the main circuit, where it is converted into AC power for the load, and supplied to battery B1 to charge it. The direction of electrical energy flow can be seen as indicated by the arrows in the figure. In this power supply mode, the electricity generated by the photovoltaic module is supplied to the inverter I1 and the battery B1 at the same time. For example, it can be applicable to the working condition when the battery B1 is not fully charged and the power generated by the photovoltaic module is greater than the load power consumption. Of course, it does not rule out the working condition where the power generated by the photovoltaic module is less than the load power consumption but still supplies power to the inverter I1 and the battery B1 at the same time.

[0068] like Figure 6As shown, when the switching portion of switch K1 is connected to the second branch 112, switch K1 is in the second switching state. At this time, second branch 112 is conductive and first branch 111 is disconnected. The photovoltaic module is electrically connected to both inverter I1 and battery B1 via second branch 112. If the photovoltaic module is unable to generate electricity at this time, battery B1 can provide its internal electrical energy to inverter I1, which in turn converts the electrical energy into AC power for the load. The direction of electrical energy flow can be shown by the arrows in the figure. This power supply mode is a pure battery discharge mode, that is, the photovoltaic module is unable to generate electricity and can only supply power to inverter I1 from battery B1. For example, it can be used in conditions where there is no light at night or during the day and the load needs power, or when the photovoltaic module fails and the load needs power.

[0069] like Figure 7 As shown, when the switching portion of switch K1 is connected to second branch 112, switch K1 is in the second switching state. At this time, second branch 112 is conductive and first branch 111 is disconnected. The photovoltaic module is electrically connected to both inverter I1 and battery B1 via second branch 112. If the power generated by the photovoltaic module is less than the power consumption of the load, the power generated by the photovoltaic module is converted to voltage by DC / DC converter D11 on second branch 112 and provided to inverter I1. At the same time, battery B1 can also provide its internal power to inverter I1, which then inverts the power into AC power for the load. The direction of power flow can be seen as indicated by the arrows in the figure. In this power supply mode, the PV panels and battery B1 are required to simultaneously power the inverter I1. This mode is suitable for operating conditions with low sunlight, such as cloudy days. In this condition, battery B1 needs to supplement some power to meet the load demand. Alternatively, if the load power consumption is too high, battery B1 still needs to supplement some power even when there is sufficient sunlight.

[0070] In one example, the switching device includes a first switching tube and a second switching tube. The first switching tube is set in the first branch 111 and the second switching tube is set in the second branch 112. In the first switching state, the first switching tube is turned on and the second switching tube is turned off. In the second switching state, the second switching tube is turned on and the first switching tube is turned off.

[0071] For example, Figure 8As shown, the first end of the switchable circuit 110 is connected to the positive pole PV1+ and the negative pole PV1- of the photovoltaic module, the second end of the switchable circuit 110 is connected to the first end of the inverter I2, and the second end of the inverter I2 is connected to the positive pole ACL (AC live wire) and the negative pole ACN (AC neutral wire) of the load; the switchable circuit includes a first branch 111 and a second branch 112 (in the figure, the first end of the first branch 111 and the first end of the second branch 112 are connected to the same node and then connected to the positive pole PV1+ of the photovoltaic module), the first branch 111 is provided with a first switch tube Q11, and the second branch 112 is provided with a DC / DC converter D21 and a second switch tube Q12; the second branch 112 is connected to the battery B2, and the first end of the inverter I2 is also connected to the battery B2 through the second branch 112.

[0072] like Figure 9 As shown, when the first switch tube Q11 is on and the second switch tube Q12 is off, the switching device is in the first switching state. At this time, the first branch 111 is on and the second branch 112 is off. The photovoltaic module is electrically connected to the inverter I2 through the first branch 111. The electrical energy generated by the photovoltaic module can be directly provided to the inverter I2 through the first branch 111, and then the inverter I2 inverts the electrical energy into AC power for use by the load. The direction of the electrical energy flow can be shown by the arrows in the figure. This power supply mode belongs to the photovoltaic power generation direct mode, which is to supply the electrical energy generated by the photovoltaic module only to the inverter I2 and not to the battery B2. For example, it can be used in conditions such as battery B2 failure or battery B2 being fully charged.

[0073] like Figure 10 As shown, when the first switch Q11 is off and the second switch Q12 is on, the switching device is in the second switching state. At this time, the second branch 112 is on and the first branch 111 is off. The photovoltaic module is electrically connected to both the inverter I2 and the battery B2 via the second branch 112. If battery B2 is not fully charged at this time, the electrical energy generated by the photovoltaic module is converted to AC power by the DC / DC converter D21 on the second branch 112 and then supplied to the inverter I2, which converts the electrical energy into AC power for the load, and to the battery B2 to charge the battery. The direction of the electrical energy flow can be shown by the arrows in the figure. In this power supply mode, the electricity generated by the photovoltaic module is supplied to the inverter I2 and the battery B2 at the same time. For example, it can be applicable to the working condition when the battery B2 is not fully charged and the power generated by the photovoltaic module is greater than the load power consumption. Of course, it does not rule out the working condition where the power generated by the photovoltaic module is less than the load power consumption but still supplies power to the inverter I2 and the battery B2 at the same time.

[0074] like Figure 11As shown, when the first switch Q11 is off and the second switch Q12 is on, the switching device is in the second switching state, at this time the second branch 112 is on and the first branch 111 is off, the photovoltaic module is electrically connected to the inverter I2 through the second branch 112, and is also electrically connected to the battery B2 through the second branch 112. If the photovoltaic module cannot generate electricity at this time, the internal electrical energy of the battery B2 can be provided to the inverter I2, and then the inverter I2 inverts the electrical energy into alternating current for the load. The flow direction of the electrical energy can be referred to the arrows shown in the figure. This power supply mode belongs to a pure battery discharge mode, that is, the photovoltaic module is in a state of being unable to generate electricity, and only the battery B2 can supply power to the inverter I2, for example, it can be applied to the case that the load needs to be powered at night or in the daytime without light, or the photovoltaic module is faulty and the load needs to be powered.

[0075] As shown, Figure 12 As shown, when the first switch Q11 is off and the second switch Q12 is on, the switching device is in the second switching state, at this time the second branch 112 is on and the first branch 111 is off, the photovoltaic module is electrically connected to the inverter I2 through the second branch 112, and is also electrically connected to the battery B2 through the second branch 112. If the photovoltaic module cannot generate electricity at this time, the internal electrical energy of the battery B2 can be provided to the inverter I2, and then the inverter I2 inverts the electrical energy into alternating current for the load. The flow direction of the electrical energy can be referred to the arrows shown in the figure. This power supply mode belongs to a pure battery discharge mode, that is, the photovoltaic module is in a state of being unable to generate electricity, and only the battery B2 can supply power to the inverter I2, for example, it can be applied to the case that the load needs to be powered at night or in the daytime without light, or the photovoltaic module is faulty and the load needs to be powered.

[0076] In one example, the switching device includes a first switch and a second switch, the first switch is arranged in the first branch 111, and the controllable circuit 110 further includes a main circuit, a first end of the main circuit is used to connect the photovoltaic module, a second end of the main circuit is connected to the first end of the first branch 111 and the first end of the second branch 112 respectively, the second switch is arranged on the main circuit, and the first switch and the second switch are both on in the first switching state, and the second switch is on in the second switching state.

[0077] Exemplarily, when the first switch tube and the second switch tube are both turned on, the photovoltaic module can also supply power to the battery through the second branch 112. In this case, the electric energy generated by the photovoltaic module is converted in voltage by the DC / DC converter 1121 on the second branch 112 and then provided to the battery, and then the electric energy is inverted into alternating current by the inverter 120 for use by the user.

[0078] Exemplarily, the inverter 120 can also be connected with the battery through the first branch 111 and the second branch 112, when the first switch tube is turned on (including the case that the first switch tube is turned on and the second switch tube is turned off, and the case that the first switch tube and the second switch tube are both turned on), if the photovoltaic module cannot supply power to the inverter 120 (corresponding to the case that the first switch tube is turned on and the second switch tube is turned off) or the electric energy generated by the photovoltaic module is less than the power consumption of the load (corresponding to the case that the first switch tube and the second switch tube are both turned on) at this time, the battery can supply power to the inverter through the second branch 112 and the first branch 111 at this time.

[0079] Exemplarily, when the second switch tube is turned on (including the case that the second switch tube is turned on and the first switch tube is turned off, and the case that the second switch tube and the first switch tube are both turned on), if the first branch 111 is in an open circuit state (corresponding to the case that the second switch tube is turned on and the first switch tube is turned off), the photovoltaic module cannot supply power to the inverter 120 at this time, and the photovoltaic module can supply power to the battery through the second branch 112; or, although the first branch 111 is in a conductive state, when the electric energy generated by the photovoltaic module is greater than the power consumption of the load, the photovoltaic module can also supply power to the battery through the second branch 112.

[0080] Exemplarily, as shown in Figure 13 The first end of the switchable circuit 110 is connected with the positive pole PV1+ and the negative pole PV1- of the photovoltaic module, the second end of the switchable circuit 110 is connected with the first end of the inverter I3, and the second end of the inverter I3 is connected with the positive pole ACL (AC live wire) and the negative pole ACN (AC neutral wire) of the load; the switchable circuit includes the first branch 111, the second branch 112 and a main circuit, the first end of the main circuit is used for connecting the positive pole PV1+ and the negative pole PV1- of the photovoltaic module, the second end of the main circuit is connected with the first end of the first branch 111 and the first end of the second branch 112 respectively, the second switch tube Q22 is arranged on the main circuit, the first switch tube Q21 is arranged on the first branch 11, and the inverter D31 is arranged on the second branch 112; the second branch 112 is connected with the battery B3, and the first end of the inverter I3 can also be connected with the battery B3 through the first branch 111 and the second branch 112.

[0081] As shown in Figure 14As shown, when the second switch Q22 and the first switch Q21 are both turned on, the first branch 111 is turned on at this time, and the photovoltaic module is electrically connected to the inverter I3 through the main circuit and the first branch 111. The electrical energy generated by the photovoltaic module can be directly provided to the inverter I3 through the main circuit and the first branch 111, and then the inverter I3 inverts the electrical energy into alternating current for the load. The flow direction of the electrical energy can be referred to the arrow shown in the figure. This power supply mode belongs to the photovoltaic power generation direct mode, which is to supply the electrical energy generated by the photovoltaic module to the inverter I3 only and not to the battery B3, for example, which can be applicable to the working conditions such as the battery B3 failure or the battery B3 being fully charged.

[0082] As shown, Figure 15 As shown, when the second switch Q22 and the first switch Q21 are both turned on, the first branch 111 is turned on at this time, and the photovoltaic module is electrically connected to the inverter I3 through the main circuit and the first branch 111. Since the second branch 112 is always in the on state, in addition to the electrical energy generated by the photovoltaic module being directly provided to the inverter I3 through the main circuit and the first branch 111, the electrical energy generated by the photovoltaic module can also be provided to the battery B3 after being converted in voltage by the DC / DC converter D31 on the main circuit and the second branch 112. The flow direction of the electrical energy can be referred to the arrow shown in the figure. In this power supply mode, the electrical energy generated by the photovoltaic module is supplied to the inverter I3 and the battery B3 at the same time, for example, which can be applicable to the working conditions such as the battery B3 not being fully charged and the electrical energy generated by the photovoltaic module being greater than the load power consumption, of course, it also does not exclude the working conditions such as the electrical energy generated by the photovoltaic module being less than the load power consumption, but still supplying power to the inverter I3 and the battery B3 at the same time.

[0083] As shown, Figure 16 As shown, when the second switch Q22 is turned off and the first switch Q21 is turned on, the first branch 111, the first end of the inverter I3 can be connected to the battery B3 through the first branch 111 and the second branch 112, and the battery B3 can provide electrical energy to the inverter I3 after converting the voltage by the DC / DC converter D31, and then the inverter I3 inverts the electrical energy into alternating current for the load. The flow direction of the electrical energy can be referred to the arrow shown in the figure. This power supply mode belongs to the pure battery discharge mode, that is, the photovoltaic module is in a state of being unable to generate electricity, and only the battery B3 can supply power to the inverter I3, for example, which can be applicable to the conditions such as night or no light during the day and the load needs to be powered, or the photovoltaic module fails and the load needs to be powered. In addition, this power supply mode can limit the current when the battery B3 is discharged through the DC / DC converter D31.

[0084] As shown, Figure 17As shown, when both the second switch Q22 and the first switch Q21 are turned on, at this time the first branch 111 is turned on, and the photovoltaic module is electrically connected to the inverter I3 through the main circuit and the first branch 111. Since the first end of the inverter I3 can be connected to the battery B3 through the first branch 111 and the second branch 112, in addition to the photovoltaic module generated electrical energy being directly provided to the inverter I3 through the main circuit and the first branch 111, the electrical energy inside the battery B3 can also be converted in voltage by the DC / DC converter D31 and then provided to the inverter I3 through the first branch 111, and then the inverter I3 inverts the electrical energy into alternating current for use by the load. The flow direction of the electrical energy can be referred to the arrows shown in the figure. In this power supply mode, the photovoltaic module and the battery B3 need to supply power to the inverter I3 at the same time, for example, it can be applied to the working condition of overcast days and the like, in which the light is not strong, and the battery B3 needs to supplement a part of the electrical energy to meet the demand of the load, or the load power consumption is too large, even if the light is sufficient, the battery B3 still needs to supplement a part of the electrical energy, and the like. Similarly, in this power supply mode, the current during discharging of the battery B3 can also be limited by the DC / DC converter D31.

[0085] It should be noted that the switch device can be implemented in other suitable manners (i.e., the specific type and setting position of the switch device are not limited) in addition to the switching switch K1, the first switch Q11 and the second switch Q12, the first switch Q21 and the second switch Q22 in the above, as long as the first branch 111 is turned on when the switch device is in the first switch state, and the photovoltaic module supplies power to the inverter through the first branch 111, which should be within the protection scope of the present application.

[0086] According to another aspect of the present application, an inverter circuit is also provided. As shown in Figure 18 The inverter circuit 100 includes an inverter 120 and a switchable circuit 110.

[0087] The switchable circuit 110 can be implemented as the switchable circuit in the above-described embodiments, and reference can be made to the description in the above, which will not be repeated here.

[0088] In one example, the inverter circuit can include a plurality of switchable circuits, the first end of each switchable circuit is connected with one photovoltaic module respectively, the second end of at least two switchable circuits is connected with the same inverter, and the second end of at least two switchable circuits is also connected with the same battery.

[0089] Exemplarily, as shown in Figure 3As shown, a situation including two switchable circuits is shown, wherein the first end of one switchable circuit is connected to the positive pole PV1+ and the negative pole PV1- of a photovoltaic component, and the switchable circuit includes a first branch, a second branch and a main circuit, the main circuit is provided with a switch K1, and the second branch is provided with a DC / DC converter D11; the first end of the other switchable circuit is connected to the positive pole PV2+ and the negative pole PV2- of another photovoltaic component, and the switchable circuit includes a first branch, a second branch and the main circuit, the main circuit is provided with a switch K2, and the second branch is provided with a DC / DC converter D12; the second ends of the two switchable circuits are connected to the same inverter I1, and the two switchable circuits are also connected to the same battery B1.

[0090] For example, Figure 8 As shown, a situation including two switchable circuits is shown, wherein a first end of one switchable circuit is connected to the positive pole PV1+ and the negative pole PV1- of a photovoltaic module, and this switchable circuit includes a first branch and a second branch, the first branch is provided with a first switch tube Q11, and the second branch is provided with a DC / DC converter D21 and a second switch tube Q12; a first end of another switchable circuit is connected to the positive pole PV2+ and the negative pole PV2- of a photovoltaic module, and this switchable circuit includes a first branch and a second branch, the first branch is provided with a first switch tube Q13, and the second branch is provided with a DC / DC converter D22 and a second switch tube Q14; the second ends of the two switchable circuits are connected to the same inverter I2, and the two switchable circuits are also connected to the same battery B2.

[0091] For example, Figure 13 As shown, a situation including two switchable circuits is shown, wherein the first end of one switchable circuit is connected to the positive pole PV1+ and the negative pole PV1- of a photovoltaic module, and the switchable circuit includes a main circuit, a first branch, and a second branch. The main circuit is provided with a second switch tube Q22, the first branch is provided with a first switch tube Q21, and the second branch is provided with a DC / DC converter D31; the first end of the other switchable circuit is connected to the positive pole PV2+ and the negative pole PV2- of a photovoltaic module, and the switchable circuit includes a main circuit, a first branch, and a second branch. The main circuit is provided with a second switch tube Q24, the first branch is provided with a first switch tube Q23, and the second branch is provided with a DC / DC converter D32; the second ends of the two switchable circuits are connected to the same inverter I3, and the two switchable circuits are also connected to the same battery B3.

[0092] According to another aspect of the present application, an energy storage device is provided, which includes a battery and an inverter circuit, wherein the battery is connected to a switchable circuit in the inverter circuit.

[0093] The inverter circuit can be implemented as the inverter circuit 100 in the above embodiments, and reference can be made to the description above, which will not be repeated here.

[0094] According to another aspect of the present application, a photovoltaic system is also provided. The photovoltaic system comprises a photovoltaic assembly and an energy storage device, and the photovoltaic assembly is connected to the switchable circuit in the inverter circuit.

[0095] The energy storage device can be implemented as the energy storage device in the above embodiments, and reference can be made to the description above, which will not be repeated here.

[0096] In one example, the photovoltaic system can comprise a plurality of photovoltaic assemblies, and each of the photovoltaic assemblies is connected to a switchable circuit.

[0097] In summary, according to the switchable circuit, the inverter circuit, the energy storage device and the photovoltaic system of the embodiments of the present application, when the switchable circuit is in the first switching state, the first branch is turned on, and the photovoltaic assembly can directly supply power to the inverter through the first branch, thereby avoiding the influence of the DC / DC converter on the direct utilization efficiency of photovoltaic power generation, and improving the direct utilization efficiency of photovoltaic power generation.

[0098] Furthermore, after the battery is fully charged, by making the switchable circuit in the first switching state to turn on the first branch, the problem that when the battery is disconnected from the bus due to overcharging, the DC / DC converter and the inverter work in the MPPT state at the same time, which can cause the system to be unstable, can be avoided.

[0099] In addition, by designing the switchable circuit to comprise the first branch and the second branch, when one of the branches fails, the other branch can still work normally, thereby improving the stability of the system.

[0100] Although the example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application. Those of ordinary skill in the art can make various changes and modifications without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0101] Similarly, it is to be understood that the embodiments of the present application can be used in the exact opposite way of that described in the examples, and that the present application should not be construed as limited to only one or the other of the embodiments described in the examples. Similarly, it is to be understood that, for the avoidance of doubt, the

[0102] Further, those skilled in the art will appreciate that the features of the various embodiments described herein are not mutually exclusive, but can be combined in different ways depending upon the needs and resources available. Thus, the application is not to be construed as limited to the specific embodiments disclosed in the examples, but rather only by the claims. Furthermore, the particular features of the application are to be construed as being each independently applied to each and every aspect and embodiment of the application and as being combinable in different ways with each and every aspect and embodiment of the application.

[0103] It is noted that the foregoing examples have been provided merely for the purposes of illustration and are not intended to limit the application as claimed. Other examples of variations that may fall within the scope of the application are possible. For example, any aspect of the application claimed can be claimed as being combinable with any other aspect or aspects of the application. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The use of the words "first", "second", and "third", etc. does not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Furthermore, the use of the terms first, second, and third, etc. does not denote any order or quantity, but rather are used to distinguish one element from another.

Claims

1. A switchable circuit, characterized in that: The switchable circuit comprises: A first branch and a second branch, wherein the first end of the first branch and the first end of the second branch are used to connect to a photovoltaic module, and the second end of the first branch and the second end of the second branch are used to connect to an inverter; The second branch is provided with a DC / DC converter, and the second branch is used to connect to a battery; When the switchable circuit is in a first switching state, the first branch is turned on, and the photovoltaic assembly is configured to supply power to the inverter through the first branch; Wherein, the switchable circuit is provided with a switch device, and when the switch device is in a first switch state, the switchable circuit is in a first switch state, and when the switch device is in a second switch state, the switchable circuit is in a second switch state; The switching device includes a switch, and the switchable circuit further includes a main circuit. The switch is provided at a first end of the main circuit, and a second end of the main circuit is used to connect to the inverter. The switch includes a switching portion. In a first switching state, the first end of the main circuit is connected to the second end of the first branch via the switching portion. In a second switching state, the first end of the main circuit is connected to the second end of the second branch via the switching portion. Alternatively, the switching device includes a first switching tube and a second switching tube, the first switching tube is arranged in the first branch, and the second switching tube is arranged in the second branch, and in the first switching state, the first switching tube is turned on and the second switching tube is turned off, and in the second switching state, the second switching tube is turned on and the first switching tube is turned off; Alternatively, the switching device includes a first switching tube and a second switching tube, the first switching tube is arranged in the first branch, the switchable circuit also includes a main circuit, the first end of the main circuit is used to connect the photovoltaic component, and the second end of the main circuit is respectively connected to the first end of the first branch and the first end of the second branch, and the main circuit is provided with a second switching tube. In the first switching state, both the first switching tube and the second switching tube are turned on, and in the second switching state, only the second switching tube is turned on.

2. The switchable circuit according to claim 1, wherein: The inverter is further configured to be connected to the battery through the first branch and the second branch. When the first switch tube is turned on, the battery is configured to supply power to the inverter through the second branch and the first branch.

3. An inverter circuit, characterized in that: The invention comprises an inverter and a switchable circuit as claimed in any one of claims 1 to 2.

4. The inverter circuit according to claim 3, wherein: There are multiple switchable circuits, and the first end of each switchable circuit is used to connect to a photovoltaic component, the second ends of at least two switchable circuits are connected to the same inverter, and the second ends of at least two switchable circuits are also used to connect to the same battery.

5. An energy storage device, characterized in that: The invention comprises a battery and the inverter circuit according to any one of claims 3 or 4, wherein the battery is connected to a switchable circuit in the inverter circuit.

6. A photovoltaic system, characterized in that: The device comprises a photovoltaic component and the energy storage device according to claim 5, wherein the photovoltaic component is connected to the switchable circuit in the inverter circuit.

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