Integrated Photovoltaic Energy Storage Module

Abstract

The present invention relates to an integrated photovoltaic energy storage module, belonging to the field of solar photovoltaic power generation, aiming to solve the problems of complex structure and installation, high cost, low efficiency and high safety risk of existing photovoltaic energy storage products. The integrated photovoltaic energy storage module includes a solar panel, an AC / DC multi-directional conversion device and an energy storage battery. The AC / DC multi-directional conversion device and the energy storage battery are installed on the back surface of the solar panel and the extension height does not exceed the back side end face of the solar panel frame. The AC / DC multi-directional conversion device includes three groups of connection terminals respectively electrically connected to the solar panel, the energy storage battery and the AC power grid, a plurality of voltage converters, a plurality of switching elements and a control chip, and the control chip is configured to: in different working modes of the integrated photovoltaic energy storage module, selectively turn on at least one switching element to establish a voltage conversion path between the corresponding two groups of connection terminals by means of at least one voltage converter.

Description

Technical Field

[0001] The present invention relates to the field of solar photovoltaic power generation, and more particularly to an integrated photovoltaic energy storage module that integrates photovoltaic power generation, energy storage, and power conversion equipment (or called a current conversion device). Background Art

[0002] With the increasing global energy demand and the concern for environmental protection, solar photovoltaic power generation, as a renewable clean energy technology, has been increasingly widely developed and applied. Photovoltaic power generation technology uses photovoltaic cell modules to convert solar energy into electrical energy and supply power to the power grid or electrical loads. And to solve the intermittency and volatility problems of solar power generation, photovoltaic power generation is generally combined with photovoltaic energy storage to form a photovoltaic power generation and energy storage system.

[0003] However, current photovoltaic power generation and energy storage power stations often operate independently. That is, the direct current generated by photovoltaic cell modules or solar panels is first inverted into alternating current by an inverter and then combined with a direct current energy storage battery through a current converter, resulting in multiple conversions of electrical energy and a significant decrease in efficiency.

[0004] The string inverter equipped for each photovoltaic string is a commonly used photovoltaic inverter at present. It has maximum power point tracking (MPPT for short) at the DC end and is connected in parallel at the AC end for grid connection. However, the string inverter does not have the single-board MPPT adjustment function, has a shortcoming effect, and relatively low efficiency. In addition, the string inverter will be subjected to DC high voltage, and there is also the problem of long-distance DC high voltage transmission. After long-term use and aging, it is easy to cause DC arcs and pose a potential safety hazard of fire. Although the MPPT and the cutting off of DC high voltage after a fire can be improved by adding optimizers, disconnectors, etc., which is beneficial to eliminating the electric shock problem for firefighters during rescue, the root problem of long-distance DC high voltage still remains unsolved, the probability of fire is still very high, and it is not cost-effective after adding disconnectors and optimizers.

[0005] Compared with the string inverter, although the traditional micro-inverter (micro-inv) solves the problem that long-distance DC high voltage transmission is easy to cause DC arcs and pose a fire hazard and can achieve MPPT adjustment for a single solar panel, avoiding the shortcoming effect of string inversion, the cost per watt is high, and the installation is complex - it is necessary to install micro-invs one by one on the track first, then install solar panels, and then connect the solar panels and micro-invs, which will greatly increase the installation cost (especially in a harsh outdoor high-altitude installation environment). In addition, the combination with the energy storage system requires an additional separate configuration of current conversion equipment, resulting in a complex system, a significant increase in cost, and the same problem of low efficiency due to multiple conversions of electrical energy.

[0006] In addition, in the current form of photovoltaic power generation and energy storage products, photovoltaic modules, inverters, and energy storage batteries are each independent products. Customers can only purchase each product separately and then rely on professional installers to combine the products. This not only significantly increases the customer acquisition cost but also greatly reduces the convenience of obtaining the products. Customers can only obtain non-standard customized product combinations from qualified distributors. The products lack generality and ease of use, and the costs of sales, transportation, installation, and maintenance are all very high. There are also significant construction risks and potential safety hazards in use. Summary of the Invention

[0007] The object of the present invention is to solve at least one of the above problems and / or other defects existing in the prior art.

[0008] The present invention provides an integrated photovoltaic energy storage module, which includes a solar panel, an AC / DC multi-way conversion device, and an energy storage battery. The solar panel is equipped with a frame extending towards its back side. The AC / DC multi-way conversion device and the energy storage battery are installed on the back surface of the solar panel and the extension height does not exceed the back side end surface of the frame. The AC / DC multi-way conversion device includes three sets of connection terminals, a plurality of voltage converters, a plurality of switching elements, and a control chip. The three sets of connection terminals are respectively electrically connected to the solar panel, the energy storage battery, and the AC power grid. Each switching element is configured to electrically connect a corresponding one of the plurality of voltage converters to another converter among the plurality of voltage converters, or to a corresponding one of the three sets of connection terminals. The control chip is configured to: in different working modes of the integrated photovoltaic energy storage module, selectively turn on at least one of the plurality of switching elements to establish a voltage conversion path between corresponding two of the three sets of connection terminals by means of at least one of the plurality of voltage converters.

[0009] According to an exemplary configuration of the present invention, in the above integrated photovoltaic energy storage module, the AC / DC multi-way conversion device and the energy storage battery can be installed on the back surface of the solar panel through an integrated frame-shaped bracket fixed to the frame within the frame.

[0010] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the energy storage battery can include a battery module composed of a combination of a plurality of blade batteries, a plurality of soft-pack batteries, or a plurality of solid-state batteries.

[0011] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the integrated photovoltaic energy storage module may further include a battery management system that is integrally provided within the AC / DC multi-way conversion device or separately provided from the AC / DC multi-way conversion device.

[0012] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the plurality of voltage converters include a first DC / DC converter, a second DC / DC converter, and a bidirectional AC / DC converter. Among them, the input side of the first DC / DC converter is electrically connected to the solar panel, the input side of the second DC / DC converter is electrically connected to the energy storage battery, the AC side of the bidirectional AC / DC converter is electrically connected to the AC power grid, and the plurality of switching elements include first to third switching elements. Among them, the first switching element belongs to the first DC / DC converter, the second switching element belongs to the second DC / DC converter, and the third switching element belongs to the bidirectional AC / DC converter. Among them, the control chip is further configured to selectively turn on two corresponding switching elements among the first to third switching elements, so as to implement different working modes of the integrated photovoltaic energy storage module by means of two corresponding converters among the first DC / DC converter, the second DC / DC converter, and the bidirectional AC / DC converter.

[0013] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the working modes of the integrated photovoltaic energy storage module may include a solar power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode. Among them, the control chip may be further configured to: in the solar power supply mode, turn on the first and third switching elements and make the bidirectional AC / DC converter work in the inversion state, so as to convert the first direct current from the solar panel into the first alternating current for powering the AC power grid by means of the first DC / DC converter and the bidirectional AC / DC converter; in the DC charging mode, turn on the first and second switching elements, so as to convert the first direct current from the solar panel into the second direct current for charging the energy storage battery by means of the first DC / DC converter and the second DC / DC converter; in the AC charging mode, turn on the second and third switching elements and make the bidirectional AC / DC converter work in the rectification state, so as to convert the first alternating current from the AC power grid into the second direct current for charging the energy storage battery by means of the bidirectional AC / DC converter and the second DC / DC converter; and in the battery power supply mode, turn on the second and third switching elements and make the bidirectional AC / DC converter work in the inversion state, so as to convert the second direct current from the energy storage battery into the first alternating current for powering the AC power grid by means of the second DC / DC converter and the bidirectional AC / DC converter.

[0014] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the first and second DC / DC converters can each be implemented as any one of a Boost boost circuit, a Buck buck circuit, and a Boost-Buck buck-boost circuit.

[0015] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the Boost-Buck buck-boost circuit may include a first switching transistor provided at the input side of the corresponding DC / DC converter, a second switching transistor provided at the output side of the corresponding DC / DC converter, and a storage inductor provided between the first switching transistor and the second switching transistor. Wherein, the control chip may be configured to control the duty cycles of the first and second switching transistors based on the output voltage of the solar panel and the charging voltage of the energy storage battery, so that the corresponding DC / DC converter operates in a boost mode or a buck mode.

[0016] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the first and second DC / DC converters may each include a first capacitor module, and the first capacitor module is composed of at least one electrolytic capacitor and at least one chip capacitor.

[0017] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the capacitance of each electrolytic capacitor is 800 μF - 3000 μF, the capacitance of each chip capacitor is 1 - 10 μF, and the diameter of each electrolytic capacitor is less than 17 mm.

[0018] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the bidirectional AC / DC converter may include an inductor, an isolation transformer, a first switching circuit, and a second switching circuit. Wherein, the input side of the first switching circuit is electrically connected to the DC side of the bidirectional AC / DC converter, the inductor is provided between the secondary side of the isolation transformer and the input side of the second switching circuit, and the output side of the second switching circuit is electrically connected to the AC side of the bidirectional AC / DC converter. Wherein, the first and second switching circuits respectively adopt a full-bridge topology structure. The four bridge arms of the first switching circuit are respectively composed of a single switching transistor. The first upper bridge arm and the first lower bridge arm of the second switching circuit are respectively composed of two switching transistors connected in series in a back-to-back manner. The second upper bridge arm and the second lower bridge arm of the second switching circuit are respectively composed of a single capacitor.

[0019] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, when the isolation transformer is within the frequency range of 8 kHz to 300 kHz, the number of turns of the primary coil of the isolation transformer is set to 3 to 6 turns, the number of turns of the secondary coil is set to 9 to 18 turns, the turns ratio is set to be between 2 and 4, the primary inductance is between 50 μH and 1.5 mH, the secondary leakage inductance is between 5 μH and 200 μH, and the height of the isolation transformer is set to be less than 17 mm.

[0020] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the bidirectional AC / DC converter may further include a second capacitor module disposed between the second switching circuit and the AC power grid, and the second capacitor module is composed of 1 to 3 safety capacitors with a height less than 17 mm.

[0021] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the bidirectional AC / DC converter may include a bidirectional full-bridge converter and an LC resonator composed of four switching tubes. The DC side of the bidirectional full-bridge converter is electrically connected to the second end of the third switching element, and the LC resonator is disposed between the AC side of the bidirectional full-bridge converter and the AC power grid.

[0022] According to an exemplary configuration of the present invention, in the integrated photovoltaic energy storage module as described in any one of the above, the bidirectional AC / DC converter may further include a third capacitor module disposed between the LC resonator and the AC power grid, and the third capacitor module is composed of 1 to 3 safety capacitors with a height less than 17 mm.

[0023] The integrated photovoltaic energy storage module according to the present invention has at least the following beneficial effects:

[0024] First, the integrated photovoltaic energy storage module integrates photovoltaic power generation, energy storage, and power conversion equipment into an organic whole, achieving the integration of functions and structures. In this way, the realization of photovoltaic energy storage products is simplified. Compared with the traditional separate photovoltaic modules, inverters, and energy storage units, users do not need to separately purchase these devices, nor do they need professional qualified personnel to match and install these devices separately. The complex customized design configuration is changed into a simple selection of components, greatly reducing the purchase and use thresholds for users, bringing great convenience to transportation, installation, and maintenance, and significantly reducing the labor costs for the transportation, installation, and maintenance of photovoltaic energy storage products. The integrated integrated photovoltaic energy storage module does not increase the volume and does not change the shape on the basis of a single solar panel, which is also beneficial for the storage, transportation, and installation of photovoltaic energy storage products.

[0025] II. The single solar panel in the integrated photovoltaic energy storage module directly realizes current conversion, energy storage, and grid connection through the DC terminal. It always operates at a low voltage of less than 80V during the DC stage, completely eradicating the risk of electric arcs easily generated in the circuit during long-term operation and aging of the DC high voltage existing in string inverters and traditional energy storage power stations. This can greatly reduce the probability of fires occurring in photovoltaic energy storage power stations, and the safety far exceeds that of traditional current conversion, energy storage, and grid connection solutions.

[0026] III. The AC-DC multi-directional conversion device in the integrated photovoltaic energy storage module directly charges electrical energy into the energy storage battery through a DC converter. Compared with the traditional photovoltaic energy storage module that converts DC into AC first and then rectifies the AC into DC to charge the energy storage battery, it reduces the two conversion processes from DC to AC and then from AC to DC, and the conversion efficiency is greatly improved.

[0027] IV. The AC-DC multi-directional conversion device in the integrated photovoltaic energy storage module integrates various different power conversion functions such as DC step-up / step-down conversion and AC-DC conversion. It can automatically switch and adapt to different working modes according to the electricity consumption requirements at different times, the lighting conditions at different times, and the grid status: (1) Grid-connected power supply by photovoltaic power generation, energy storage, and power supply to loads; (2) Grid-connected power supply by stored energy and power supply to loads; (3) Charging the energy storage battery by the grid power generation device, etc. Compared with traditional solar power stations and energy storage power stations, the power dispatching and distribution switching between them require multiple authorizations from the grid and the owner, long-distance transmission, and consideration of complex over-network interest games and other factors. However, the present invention has obvious advantages in terms of dispatching efficiency, convenience, and transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The features and advantages of the present invention will be clearly understood from the following detailed description with reference to the accompanying drawings. It should be understood that the following drawings are merely schematic and not necessarily drawn to scale, and thus should not be regarded as limiting the present invention, where:

[0029] Figure 1 Shows an overall schematic diagram of the integrated photovoltaic energy storage module connected to the grid according to the present invention.

[0030] Figure 2-1 Shows a rear view of the integrated photovoltaic energy storage module according to the first exemplary embodiment of the present invention.

[0031] Figure 2-2 Shows a cross-sectional view of the integrated photovoltaic energy storage module according to the first exemplary embodiment of the present invention.

[0032] Figure 3-1 Shows a rear view of the integrated photovoltaic energy storage module according to the second exemplary embodiment of the present invention.

[0033] Figure 3-2 A cross-sectional view of an integrated photovoltaic energy storage module according to a second exemplary embodiment of the present invention is shown.

[0034] Figure 4 An internal structure diagram of an AC-DC multi-way conversion device in an integrated photovoltaic energy storage module according to an exemplary embodiment of the present invention is shown.

[0035] Figure 5-1 A circuit state diagram of the AC-DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in a solar power supply mode is shown.

[0036] Figure 5-2 A circuit state diagram of the AC-DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in a DC charging mode is shown.

[0037] Figure 5-3 A circuit state diagram of the AC-DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in an AC charging mode is shown.

[0038] Figure 5-4 A circuit state diagram of the AC-DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in a battery power supply mode is shown.

[0039] Figure 6 A schematic diagram of the output voltage waveform of the solar panel in the integrated photovoltaic energy storage module according to the present invention is shown.

[0040] Figure 7-1 An internal circuit diagram of the first or second DC / DC converter implemented as a Boost boost circuit is shown.

[0041] Figure 7-2 An internal circuit diagram of the first or second DC / DC converter implemented as a Buck buck circuit is shown.

[0042] Figure 7-3 An internal circuit diagram of the first or second DC / DC converter implemented as a Boost-Buck buck-boost circuit is shown.

[0043] Figure 8-1 A schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using an isolation transformer structure is shown.

[0044] Figure 8-2 A schematic diagram of the internal circuit structure of the bidirectional AC / DC converter using a non-isolation transformer structure is shown. Detailed implementation

[0045] Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to enable those skilled in the art to more fully understand and implement the present invention. However, it is obvious to those skilled in the art that some of these specific details may not be required for the implementation of the present invention. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, the present invention can be implemented by any combination of the features and elements described below, regardless of whether they relate to different embodiments. Therefore, the aspects, features, embodiments, and advantages below are for illustrative purposes only and should not be regarded as elements or limitations of the claims, unless expressly recited in the claims.

[0046] In the following, terms such as "first", "second", etc. are used to describe the elements of the present application. These terms are only used to distinguish the various elements and not to limit the nature, order, or number of these elements. The terms "comprising" and "having" are used to indicate an open inclusion meaning and mean that additional elements / components may exist in addition to the listed elements / components.

[0047] Figure 1 A circuit connection diagram of an integrated photovoltaic energy storage component according to the present invention is schematically shown. The integrated photovoltaic energy storage component includes a photovoltaic cell component as a basic element. In the present application, the photovoltaic cell component specifically refers to a single solar panel 1, which may have a relatively low open-circuit voltage of less than 80V. In addition, the integrated photovoltaic energy storage component further includes an AC-DC multi-directional conversion device 2 and an energy storage battery 3. As Figure 1 shown, the AC-DC multi-directional conversion device 2 connects the solar panel 1, the energy storage battery 3, and the AC power grid 4 to each other and is configured to be able to perform desired power conversions between any two of these three as needed. For example, a DC step-up / step-down conversion is performed between the solar panel 1 and the energy storage battery 3 through the AC-DC multi-directional conversion device 2, or an AC-DC conversion is performed between each of the solar panel 1 and the energy storage battery 3 and the AC power grid 4 through the AC-DC multi-directional conversion device 2. That is to say, the AC-DC multi-directional conversion device 2 is a multi-purpose power conversion unit that integrates a variety of different power conversion functions. In the present application, the AC power grid 4 includes not only ordinary large power grids but also microgrids or other electrical equipment that can receive or supply power.

[0048] The integrated photovoltaic energy storage component according to the present invention is an integrated structure that integrates the solar panel 1, the AC-DC multi-directional conversion device 2, and the energy storage battery 3 in terms of hardware. Figure 2-1 and Figure 2-2 respectively show a rear view and a cross-sectional view of a first exemplary configuration of this integrated structure, where Figure 2-2 the cross-sectional view is taken along the Figure 2-1 A-A line inFigure 2-1 and Figure 2-2 The integrated photovoltaic energy storage module shown in Figure 2-2 includes a solar panel 1, an AC / DC multi-directional conversion device 2, and an energy storage battery 3 that are installed together. More specifically, both the AC / DC multi-directional conversion device 2 and the energy storage battery 3 are installed on the back surface of a single solar panel 1. As described above, since the AC / DC multi-directional conversion device 2 is a multi-purpose power conversion unit, it is advantageously encapsulated in a single housing. The energy storage battery 3 can be a battery module composed of multiple battery cells, and battery types such as blade batteries, soft-pack batteries, or solid-state batteries can be used, for example.

[0049] The solar panel 1 is equipped with a frame 11 (such as, but not limited to, the illustrated rectangle) that extends towards its back side (i.e., the direction pointing out of the paper plane in the rear view of Figure 2-1 , or the direction towards the right side in the cross-sectional view of Figure 2-2 ) and is made of aluminum, for example. After the AC / DC multi-directional conversion device 2 and the energy storage battery 3 are installed in place on the back surface of the solar panel 1, their extended height (referring to the maximum height that any part of them can reach in the direction towards the back side of the solar panel 1) does not exceed the back side end surface of the frame 11 (shown as a rectangular frame located at the outer periphery of the solar panel 1 in Figure 2-1 ).

[0050] Except for the solar panel 1, the AC / DC multi-directional conversion device 2 and the energy storage battery 3 are the components that occupy the most space in the thickness direction (the direction perpendicular to the paper plane in Figure 2-1 , or the left-right direction in Figure 2-2 ) of the entire photovoltaic energy storage module. Moreover, their extended height on the back surface of the solar panel 1 does not exceed the back side end surface of the frame 11 of the solar panel 1. Therefore, the thickness of the entire photovoltaic energy storage module is equal to the thickness of the original solar panel 1 (including its frame 11), thus maintaining the regular shape of the single solar panel 1. In this way, it is particularly convenient to stack multiple integrated photovoltaic energy storage modules according to the present invention, which is beneficial for the warehousing, transportation, and installation of photovoltaic energy storage module products in a space-saving and cost-saving manner. In the integrated photovoltaic energy storage module according to the present invention, as will be described in more detail below, particularly by designing the structure and / or arrangement of the AC / DC multi-directional conversion device 2 and the energy storage battery 3, the thickness of the single solar panel 1 will not increase and its shape will not change even after integrating the AC / DC multi-directional conversion device 2 and the energy storage battery 3 on the conventional solar panel 1. Advantageously, the integrated photovoltaic energy storage module according to the present invention can be realized without increasing the external dimensions of the existing mainstream photovoltaic module (the overall thickness of the mainstream photovoltaic module is not greater than 36 mm; the height of the back gap is not greater than 28 mm, and the height of the back gap refers to the distance between the back surface of the solar panel in the photovoltaic module and the back side end surface of its frame).​​​​​​​​​​

[0051] As Figure 2-1 and Figure 2-2 shown, the AC / DC multi-way conversion device 2 and the energy storage battery 3 can be mounted on the back surface of the solar panel 1 through the bracket 12. The bracket 12 can be fixed to the frame 11 within the frame 11, for example, and can be formed into various suitable configurations for facilitating the installation of the AC / DC multi-way conversion device 2 and the energy storage battery 3, such as, but not limited to, the illustrated integrated grid-shaped bracket, which defines a plurality of grids, so that the AC / DC multi-way conversion device 2 and the energy storage battery 3 can be respectively assembled in different grids. In Figure 2-1 and Figure 2-2 the first embodiment shown, the AC / DC multi-way conversion device 2 is mounted at the central position of the bracket 12, and multiple battery cells (such as the illustrated blade batteries) of the energy storage battery 3 are disposed on both sides of the AC / DC multi-way conversion device 2. Compared with the AC / DC multi-way conversion device 2 and the energy storage battery 3, the bracket 12, which is much simpler in structure and function, also has a more compact size. Thus, after being fixedly positioned on the frame 11, the extended height of the bracket 12 will not exceed the back end face of the frame 11. The bracket 12 can be fixed to the frame 11 by various suitable means, such as, but not limited to, screw fixing, riveting fixing or screw block fixing methods.

[0052] To reduce the thickness dimension, the energy storage battery 3 can be a battery module formed by multiple blade batteries, multiple soft-pack batteries or multiple solid-state batteries. To minimize the thickness of the energy storage battery 3 to avoid its extended height exceeding the back end face of the frame 11 of the solar panel, multiple battery cells (such as multiple blade batteries or multiple soft-pack batteries or multiple solid-state batteries) constituting the energy storage battery 3 can be arranged in a single-layer tiled form. However, when the thickness requirement is met, at least a part of the multiple battery cells can also be arranged in a stacked manner (such as for blade batteries with relatively small battery cell thickness). Each battery cell in the energy storage battery 3 can be flexibly arranged according to the configuration of the bracket 12 and the space layout within the frame 11 into different modules. The number and arrangement position of the modules and the number and arrangement manner of the battery cells in each module can all be flexibly adjusted, so as to form energy storage batteries 3 with different capacities and thus photovoltaic energy storage component products with different specifications.

[0053] As an example, the energy storage battery 3 can also be equipped with a battery management system (BMS), which is used to monitor and manage the charging and discharging processes of each battery cell in the energy storage battery, so as to ensure the safe operation of the energy storage battery, prevent overcharging or over-discharging, and at the same time achieve the balancing control inside the battery. The battery management system can be communicatively connected to the energy storage battery 3 and its battery cells by wired or wireless means. In Figure 2-1 and Figure 2-2In the illustrated embodiment, the battery management system can be integrally disposed within the AC / DC multi-way conversion device 2, thus not occupying extra space, and the extension height of the AC / DC multi-way conversion device 2 including the battery management system on the back side of the solar panel 1 does not exceed the back side end face of the frame 11 either.

[0054] Figure 3-1 and Figure 3-2 respectively show the rear views of the integrated photovoltaic energy storage module according to the second exemplary embodiment of the present invention. Among them, Figure 3-2 The cross-sectional view is taken along the Figure 3-1 A-A line in Figure 3-1 and Figure 3-2 In the second embodiment shown in Figure 3-1 and Figure 3-2 the battery management system 31 can also be separately disposed from the AC / DC multi-way conversion device 2. As shown in Figure 2-1 and Figure 2-2 the battery management system 31 is also mounted on the back surface of the solar panel 1 through the bracket 12. For this purpose, compared with the first embodiment shown in Figure 2-1 and Figure 2-2 the integrated lattice-shaped bracket 12 is slightly adjusted in structure, and an assembly lattice is also provided for the battery management system 31. Here, the independent battery management system 31 has a smaller size than the AC / DC multi-way conversion device 2, and its extension height after being mounted on the back surface of the solar panel 1 through the bracket 12 does not exceed the back side end face of the frame 11 either.

[0055] When meeting the overall size requirements of the photovoltaic energy storage module of the present invention, various setting methods of the battery management system, including the embodiments shown in Figure 2-1 , Figure 2-2 and Figure 3-1 , Figure 3-2 are all feasible and will not affect the overall performance of the photovoltaic energy storage module.

[0056] After various components of the integrated photovoltaic energy storage module described above are installed, the extension height of components such as the AC / DC multi-way conversion module 2, the energy storage battery 3 and its battery management system, the bracket 12, and various connection wires and fixing structures on the back surface of the solar panel 1 does not exceed the back side end face of the frame 11, making the overall shape of the entire photovoltaic energy storage module identical to that of a single solar panel 1. Such an integrated photovoltaic energy storage module can also be conveniently equipped with a protective film or a protective shell to protect various components from being damaged during transportation and installation, and can also be used for waterproofing and dustproofing, etc. to resist the influence of the external use environment.

[0057] Next, the AC / DC multi-way conversion device in the integrated photovoltaic energy storage module according to an exemplary embodiment of the present invention will be described in detail, which is the core of the photovoltaic energy storage module. Figure 4The internal structure diagram of the AC-DC multi-way conversion device is shown.

[0058] As Figure 4 shown in the figure, the AC-DC multi-way conversion device includes three sets of connection terminals, multiple voltage converters, multiple switching elements, and a control chip. The three sets of connection terminals are respectively the first set of connection terminals electrically connected to the positive and negative poles PV+ and PV- of the solar panel 1, the second set of connection terminals electrically connected to the positive and negative poles BAT+ and BAT- of the energy storage battery 3, and the third set of connection terminals electrically connected to the live wire L and neutral wire N of the AC power grid.

[0059] The multiple voltage converters can include a DC step-up / step-down converter (i.e., a DC / DC module) and an AC-DC bidirectional converter (i.e., a bidirectional AC / DC module). Among them, the DC / DC module can be composed of one or more of a boost circuit Boost, a buck circuit Buck, and a boost-buck circuit Boost-Buck. The bidirectional AC / DC module can include a rectifier circuit and an inverter circuit. The rectifier circuit and the inverter circuit can be either the same hardware circuit or different hardware circuits.

[0060] Each switching element plays a key role in connecting each module inside the AC-DC multi-way conversion device. Specifically, under the control of the control chip 7, depending on the different operating modes of the integrated photovoltaic energy storage module, each switching element can electrically connect the corresponding voltage converter to another voltage converter or to the corresponding connection terminal, thereby establishing the required voltage conversion path between the corresponding two sets of connection terminals. For example, when it is necessary to transfer the electrical energy of the solar panel to the energy storage battery, by controlling the corresponding switching elements, the output side of the solar panel is connected to the DC / DC converter, and then the output of the DC / DC converter is connected to the input side of the energy storage battery through another switching element, thereby realizing the transfer of electrical energy from the solar panel to the energy storage battery.

[0061] The control chip 7 is the "brain" of the entire conversion device. It can monitor the circuit state of the conversion device in real time, selectively control the on / off states of each switching element and the operating states of each conversion module to achieve various voltage conversion functions of the AC-DC bidirectional conversion device. By controlling the switching elements and different combinations of switching tubes in the AC-DC multi-way conversion device, the AC-DC bidirectional conversion device can realize multi-way voltage conversion functions from AC to DC, from DC to AC, or from DC to DC. Further, by using the AC-DC bidirectional conversion device, at least four operating modes of the integrated photovoltaic energy storage module can be realized, including a solar power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode.

[0062] Herein, the "solar power supply mode" refers to feeding power into the AC grid or a microgrid by means of solar panels. In this mode, a DC / DC converter and a bidirectional AC / DC converter are required to convert the DC power output by the solar panels into AC power and finally transmit it to the AC grid. The "DC charging mode" refers to charging an energy storage battery by means of solar panels. In this mode, a DC / DC converter is required to step up or step down the DC power output by the solar panels and finally transmit it to the energy storage battery. The "AC charging mode" refers to charging an energy storage battery by means of a power generation device in the AC grid. In this mode, a bidirectional AC / DC converter and a DC / DC converter are required to convert the AC power in the AC grid into DC power and then perform a step-up / step-down operation, and finally transmit it to the energy storage battery. "Battery power supply" refers to feeding power to the AC grid (or microgrid) by means of an energy storage battery. In this mode, a DC / DC converter and a bidirectional AC / DC converter are required to step up / step down the DC power output by the energy storage battery and then convert it into AC power, and finally transmit it to the AC grid.

[0063] Optionally, the control chip 7 can also monitor the output current and output voltage generated by the solar panels in real time, and calculate the MPPT to achieve maximum power point tracking, so that the solar panel 1 is in the highest working efficiency state when feeding power into the grid or charging the energy storage battery. Among them, the power supply (PS) circuit of the control chip 7 can automatically match the power supply output of the solar panels or the energy storage battery.

[0064] Figures 5-1 to 5-4 Schematic diagrams showing different circuit states of the AC / DC multi-way conversion device in different working modes of the integrated photovoltaic energy storage module according to the present invention are respectively shown. The following combines Figures 5-1 to 5-4 to elaborate in detail the circuit states and working principles of the AC / DC multi-way conversion device in different working modes.

[0065] Figure 5-1 A circuit state diagram of the AC / DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in the solar power supply mode is shown. Figure 5-2 A circuit state diagram of the AC / DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in the DC charging mode is shown. Figure 5-3 A circuit state diagram of the AC / DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in the AC charging mode is shown. Figure 5-4 A circuit state diagram of the AC / DC multi-way conversion device in the integrated photovoltaic energy storage module according to the present invention in the battery power supply mode is shown.

[0066] As Figures 5-1 to 5-4As shown in the figure, the AC-DC multi-way conversion device has three sets of connection terminals, which are respectively connected to the positive and negative poles PV+ and PV- of the solar panel, the positive and negative poles BAT+ and BAT- of the energy storage battery, and the live wire L and neutral wire N of the AC power grid (or microgrid).

[0067] The core part of the AC-DC multi-way conversion device is composed of multiple voltage converters and multiple switching elements. Depending on the working mode to be achieved by the integrated photovoltaic energy storage module, by selectively turning on the corresponding switching elements with the aid of the control chip 7 and controlling the working states of the voltage converters, a corresponding voltage conversion path can be established between the corresponding two sets of connection terminals.

[0068] The AC-DC multi-way conversion device has a first DC / DC converter 8, a second DC / DC converter 9, and a bidirectional AC / DC converter 10, as well as first, second, and third switching elements S1, S2, and S3. Each switching element belongs to a corresponding switching element in the AC-DC multi-way conversion device. For example, the first switching element S1 belongs to the first DC / DC converter 8, the second switching element S2 belongs to the second DC / DC converter 9, and the third switching element S3 belongs to the bidirectional AC / DC converter 10.

[0069] In this article, the expression "belongs to" describes the specific associated configuration / assignment relationship between the switching element and the converter, that is, the switching element is assigned or designated to work in cooperation with a specific converter. This "assignment" relationship indicates that although the specific position of the switching element can be flexibly set in the circuit, its main function is to serve the voltage converter to which it "belongs", and by controlling the current flow path related to the converter, different working modes of the photovoltaic energy storage module are realized. Therefore, the expression "belongs to" in this article is not intended to limit the physical position of the switching element, but to emphasize its start control relationship with a specific voltage converter in the system control logic.

[0070] In Figures 5-1 to 5-4In the shown circuit diagram, an exemplary connection relationship between each switching element and each converter is shown. Among them, the input side of the first DC / DC converter 8 is electrically connected to the positive and negative electrodes PV+ and PV- of the solar panel, and the input side of the second DC / DC converter 9 is electrically connected to the positive and negative electrodes BAT+ and BAT- of the energy storage battery. The first switching element S1 connects the output side of the first DC / DC converter 8 to the first end of the third switching element S3, and the second switching element S2 connects the output side of the second DC / DC converter 9 to the first end of the third switching element S3. The DC side of the bidirectional AC / DC converter 10 is connected to the second end of the third switching element S3, and its AC side is connected to the AC power grid (or microgrid). The on / off states of these switching elements, the operating states of the DC / DC converters (boost or buck), and the operating states of the AC / DC converters (inversion or rectification) are overall controlled by the control chip to ultimately achieve different operating modes of the photovoltaic energy storage module.

[0071] In Figure 5-1 , the photovoltaic energy storage module operates in the solar power supply mode. The control chip 7 turns on the first and third switching elements S1 and S3, so that the first direct current generated by the solar panel is voltage-regulated (boost or buck) through the first DC / DC converter 8, and then is inverted into the first alternating current through the bidirectional AC / DC converter 10 and finally supplies power to the AC power grid. In this solar power supply mode, the switching elements S1 and S3 are closed, S2 is open, and the bidirectional AC / DC converter 10 is in the inversion state, and the electric energy of the solar panel can be used to achieve grid-connected power generation or supply power to the microgrid.

[0072] In Figure 5-2 , the photovoltaic energy storage module operates in the DC charging mode. The control chip 7 turns on the first and second switching elements S1 and S2, so that the first direct current generated by the solar panel is converted into an intermediate direct current through the first DC / DC converter 8, and then is converted into the second direct current suitable for charging the energy storage battery through the second DC / DC converter 9. At this time, the first and second DC / DC converters are in the DC boost or buck state, depending on the output voltage of the solar panel and the charging required voltage of the energy storage battery. In this DC charging mode, the switching elements S1 and S2 are closed, S3 is open, and the bidirectional AC / DC converter 10 does not work, and the efficient charging of the energy storage battery with the electric energy of the solar panel can be achieved.

[0073] In Figure 5-3In this case, the photovoltaic energy storage component operates in the AC charging mode. The control chip 7 turns on the second and third switching elements S2 and S3, and makes the bidirectional AC / DC converter 10 operate in the rectification state. At this time, the first alternating current from the AC power grid is rectified by the bidirectional AC / DC converter 10 and then converted into direct current. This direct current is then regulated in voltage by the second DC / DC converter 9 and converted into the second direct current suitable for charging the energy storage battery. In this AC charging mode, the bidirectional AC / DC converter 10 is in the rectification state, S2 and S3 are closed, and S1 is open, enabling the use of the alternating current from the AC power grid to charge the energy storage battery.

[0074] In Figure 5-4 In this case, the photovoltaic energy storage component operates in the battery power supply mode. The control chip 7 turns on the second and third switching elements S2 and S3, and makes the bidirectional AC / DC converter 10 operate in the inversion state. At this time, the direct current generated by the energy storage battery is regulated in voltage (boosted or bucked) by the second DC / DC converter 9, and then inverted by the bidirectional AC / DC converter 10 into the first alternating current, which ultimately supplies power to the AC power grid. In this battery power supply mode, the bidirectional AC / DC converter 10 is in the inversion state, S2 and S3 are closed, and S1 is open, enabling the use of the direct current from the energy storage battery to supply power to the AC power grid.

[0075] By flexibly switching between these four operating modes shown in Figures 5-1 to 5-4 the integrated photovoltaic energy storage component of the present invention can achieve the efficient utilization of the solar panel, the flexible charging and discharging of the energy storage battery, and the stable interaction with the AC power grid, and can adapt to different operating scenarios.

[0076] Although Figures 5-1 to 5-4 it is shown in that the switching elements S1 - S3 are respectively arranged between the voltage converters, this arrangement is only illustrative and not the only feasible implementation. In fact, the positions of these switching elements can be flexibly adjusted. For example, they can also be arranged on the connection end side of the AC-DC multi-way conversion device to directly control the connection and disconnection of the connection end. This arrangement can also effectively control the voltage conversion path, thereby achieving the flexible switching of the current flow path of the photovoltaic energy storage component in different operating modes. Therefore, even if the setting positions of the switching elements change, as long as they can selectively connect or disconnect the relevant conversion paths according to the instructions of the control chip 7, the expected operating mode of the photovoltaic energy storage component can be achieved.

[0077] Importantly, regardless of the position where the switching element is set, various types of switching devices can be adopted to implement it, including but not limited to metal-oxide-semiconductor field-effect transistors (abbreviated as "MOSFET"), triodes, relays, or insulated-gate bipolar transistors (abbreviated as "IGBT"), etc. Due to their different characteristics and applicable scenarios, these switching devices can be selected according to the specific requirements of the AC-DC multi-way conversion device to ensure the efficient, safe, and reliable operation of the converter. In addition, the switching elements S1-S3 can either be independently set switches or switching tubes shared with the DC / DC converter or the bidirectional AC / DC converter, and the switching tubes are, for example, selected from the group including diodes, triodes, thyristors, MOS tubes, and IGBTs.

[0078] In this AC-DC multi-way conversion device, the first and second DC / DC converters adopt a highly flexible circuit design to adapt to different voltage conversion requirements. The first and second DC / DC converters are each implemented as any one of a Boost boost circuit, a Buck buck circuit, and a Boost-Buck buck-boost circuit.

[0079] Figure 6 The schematic diagram showing the output voltage waveform of the solar panel in the integrated photovoltaic energy storage module according to the present invention is shown. As Figure 6 shown, the output voltage of the solar panel is not a stable DC voltage, but is doped with high-frequency or low-frequency noise signals. Therefore, before performing buck-boost operation on the output voltage of the solar panel, it is necessary to filter it with the aid of a filtering module, and the filtering module can be, for example, integrated inside the first DC / DC converter.

[0080] Figure 7-1 The internal circuit diagram of the first or second DC / DC converter implemented as a Boost boost circuit is shown. This Boost boost circuit is applicable to the case where the output voltage of the solar panel is lower than the charging voltage of the energy storage battery. First, in order to filter the noise signals in the output voltage of the solar panel, the Boost boost circuit includes a first capacitor module on the input side. This capacitor module is composed of electrolytic capacitors C1-C4 and chip capacitors C6-C9 connected in parallel. Among them, the diameter of the electrolytic capacitors C1-C4 is less than 17 mm, the number is 4-8, the capacitance is 800 μF-3000 μF, the number of the chip capacitors C6-C9 is 4-14, and the capacitance is 1-10 μF.

[0081] Through electrolytic capacitors C1 - C4 and chip capacitors C6 - C9, it is possible to better suppress the ripple and high - order harmonic interference in the input signal of the boost circuit. Among them, electrolytic capacitors can effectively suppress the low - frequency filtering part, and chip capacitors can make up for the deficiency of electrolytic capacitors in filtering high - frequency parts, reducing the diameter of electrolytic capacitors and extending their lifespan. In short, the design of this capacitor module ensures its compact layout in a limited space and also ensures the stability of the output voltage of the DC / DC converter.

[0082] Downstream of this capacitor module, a conventional Boost circuit is provided, which consists of a storage inductor L, two switching transistors Q1 and Q2, and a storage capacitor C5. The control terminals of switching transistors Q1 and Q2 are P1 and P2 respectively, and the control terminals P1 and P2 are each connected to a control chip 7, such that switching transistors Q1 and Q2 are alternately turned on / off under the control of the control chip 7, thereby realizing the voltage - boosting function of the circuit. Here, switching transistor Q2 can be a MOSFET or a diode. If it is a MOSFET, it can share the same switch with the switching element S1 or S2 in the AC / DC multi - way conversion device.

[0083] Figure 7-2 The internal circuit diagram of the first or second DC / DC converter implemented as a Buck buck - down circuit is shown. This Buck buck - down circuit is applicable to the situation where the output voltage of the solar panel is higher than the charging voltage of the energy storage battery. Similarly, in order to filter out the noise signal in the output voltage of the solar panel, the Buck buck - down circuit includes a capacitor module on the input side. This capacitor module is formed by connecting electrolytic capacitors C1 - C4 and chip capacitors C6 - C9 in parallel. Among them, the diameter of electrolytic capacitors C1 - C4 is less than 17 mm, the number is 4 - 8, the capacitance is 800 μF - 3000 μF, the number of chip capacitors C6 - C9 is 4 - 14, and the capacitance is 1 - 10 μF.

[0084] Through the combined filtering of electrolytic capacitors C1 - C4 and chip capacitors C6 - C9, it is possible to better suppress the ripple and high - order harmonic interference in the input signal of this buck - down circuit. Among them, electrolytic capacitors can effectively suppress the low - frequency filtering part, and chip capacitors can make up for the deficiency of electrolytic capacitors in filtering high - frequency parts, reducing the diameter of electrolytic capacitors and extending their lifespan.

[0085] Downstream of this capacitor module, a conventional Buck circuit is provided, which consists of a storage inductor L, two switching transistors Q1 and Q2, and a storage capacitor C5. The control terminals of switching transistors Q1 and Q2 are P1 and P2 respectively, and the control terminals P1 and P2 are each connected to a control chip, such that switching transistors Q1 and Q2 are alternately turned on / off under the control of the control chip, thereby realizing the voltage - bucking function of the circuit. Here, switching transistor Q2 can be a MOSFET or a diode.

[0086] Figure 7-3The internal circuit diagram of the first or second DC / DC converter implemented as a Boost-Buck buck-boost circuit is shown. This Boost-Buck buck-boost circuit is applicable to the situation where the output voltage of the solar panel is sometimes higher than the charging voltage of the energy storage battery and sometimes lower than the charging voltage of the energy storage battery. In order to filter out the noise signals in the output voltage of the solar panel, this Boost-Buck buck-boost circuit includes a capacitor module on the input side. This capacitor module is composed of electrolytic capacitors C1 - C4 and chip capacitors C6 - C9 connected in parallel. Among them, the diameter of the electrolytic capacitors C1 - C4 is less than 17 mm, the number is 4 - 8, the capacitance is 800 μF - 3000 μF, the number of chip capacitors C6 - C9 is 4 - 14, and the capacitance is 1 - 10 μF.

[0087] Through the combined filtering of the electrolytic capacitors C1 - C4 and the chip capacitors C6 - C9, the ripple and high-order harmonic interference in the input signal of this buck-boost circuit can be better suppressed. Among them, the electrolytic capacitor can effectively suppress the low-frequency filtering part, and the chip capacitor can make up for the deficiency of the electrolytic capacitor in filtering the high-frequency part, reducing the diameter of the electrolytic capacitor and extending its life.

[0088] Downstream of this capacitor module, a conventional Boost-Buck circuit is provided, which is composed of an energy storage inductor L, two switching transistors Q1 and Q2, and an energy storage capacitor C5. Among them, the switching transistor Q1 is arranged on the input side of this Boost-Buck circuit, the switching transistor Q2 is arranged on the output side of this Boost-Buck circuit, and the energy storage inductor L is arranged between the switching transistors Q1 and Q2. Among them, the switching transistor Q2 can be a MOSFET or a diode. If it is a MOSFET, it can share the same switch with the switching element S1 or S2 in the AC-DC multi-way conversion device.

[0089] The control terminals of the switching transistors Q1 and Q2 are P1 and P2 respectively, and the control terminals P1 and P2 are each connected to the control chip 7. According to the output voltage of the solar panel and the charging voltage of the energy storage battery, the control chip can dynamically adjust the duty cycles of Q1 and Q2, so as to realize the free switching of this Boost-Buck circuit between the boost mode and the buck mode. For example, when the output voltage of the solar panel is lower than the charging voltage of the energy storage battery, this Boost-Buck circuit is made to work in the boost mode; when the output voltage of the solar panel is higher than the charging voltage of the energy storage battery, this Boost-Buck circuit is made to work in the buck mode.

[0090] In this AC-DC multi-way conversion device, depending on the specific application scenario of the integrated photovoltaic energy storage module (for example, the operating voltage of the connected AC power grid), the bidirectional AC / DC converter can adopt two forms: an isolated transformer structure and a non-isolated transformer structure.

[0091] Figure 8-1 A schematic diagram showing the internal circuit structure of a bidirectional AC / DC converter adopting an isolated transformer structure is presented. In Figure 8-1 this case, the circuit design of the bidirectional AC / DC converter uses an isolated transformer to meet the requirements for electrical isolation in specific scenarios (such as in the United States). This bidirectional AC / DC converter is modified based on the dual active bridge (DAB) circuit to achieve bidirectional and efficient conversion between direct current and alternating current.

[0092] The core structure of the modified dual active bridge circuit includes an isolated transformer T, a first switch circuit, a second switch circuit, and an inductor Ls. The input side of the first switch circuit is connected to the DC side of the bidirectional AC / DC converter. The inductor Ls is arranged between the secondary side of the isolated transformer T and the input side of the second switch circuit. The output side of the second switch circuit is electrically connected to the AC side of this bidirectional AC / DC converter. Here, the leakage inductance of the secondary side of the isolated transformer T can also be used to replace the inductor Ls, thereby omitting the need to additionally set a secondary inductor.

[0093] As an optional example, on the primary side of the isolated transformer T, especially between the output side of the first switch circuit and the primary side of the isolated transformer T, one or more capacitors can be separately provided to filter out the DC component in the electrical signal received by the primary side of the isolated transformer. As another optional example, on the primary side of the isolated transformer T, another resonant circuit composed of a primary inductor and a primary capacitor can also be provided.

[0094] Both the first and second switch circuits adopt a full-bridge topology structure. Among them, the four bridge arms in the first switch circuit are respectively composed of switching transistors Q1 - Q4, and the corresponding control terminals P1 - P4 of these four switching transistors Q1 - Q4 are each connected to the control chip 7.

[0095] In the second switch circuit, the first upper bridge arm and the first lower bridge arm forming the first half-bridge are composed of two switching transistors (MOSFETs Q5, Q6 and Q7, Q8) connected in series in a back-to-back manner, and the second upper bridge arm and the second lower bridge arm forming the second half-bridge are composed of single capacitors (C1 and C2) respectively. That is to say, on the AC side of this bidirectional AC / DC converter, one terminal of the secondary side of the isolated transformer T is connected in series with two groups of parallel circuits. One group is formed by connecting the switching transistors Q5, Q6 and C1 in series, and the other group is formed by connecting the switching transistors Q7, Q8 and C2 in series. The sources of the switching transistors Q5 and Q6 are connected, and the sources of the switching transistors Q7 and Q8 are connected, and finally return to the other terminal of the secondary side of the isolated transformer T. The control terminals P1 - P8 of the switching transistors Q1 - Q8 are sequentially turned on by the control chip 7 according to requirements such as bidirectional rectification or inversion mode, and synchronization of the AC power frequency (phase).

[0096] On the secondary side of the isolated transformer T, based on Figure 8-1The topology of the second switching circuit and the inductance Ls (or the leakage inductance of the transformer) set as shown, the control chip 7 can selectively control the on / off states of the four switching transistors Q5, Q6, Q7, and Q8, so as to form a first resonance circuit via the inductance Ls and the capacitor C1, or form a second resonance circuit via the inductance Ls and the capacitor C2, and finally achieve the required voltage / current waveform on the secondary side of the transformer.

[0097] Specifically, as Figure 8-1 shown, when the bidirectional AC / DC converter operates in the rectification mode, for example, when it is necessary to charge the energy storage battery with the alternating current from the AC power grid, at this time, the AC side of the bidirectional AC / DC converter receives the AC signal L-N from the AC power grid. During the positive half-cycle of this AC signal L-N, with the help of the control chip 7, the switching transistors Q6 and Q8 in the second switching circuit are kept constantly on, and the switching transistors Q5 and Q7 alternately perform high-frequency on / off operations (that is, when Q5 is on, Q7 is off, and vice versa). On the contrary, during the negative half-cycle of L-N, with the help of the control chip 7, the switching transistors Q5 and Q7 are kept constantly on, and the switching transistors Q6 and Q8 alternately perform high-frequency on / off operations. At the same time, on the DC side of this bidirectional AC / DC converter, the switching transistors Q1, Q4 and the switching transistors Q2, Q3 in the first switching circuit are alternately turned on to cooperate with the actions of the switching transistors on the AC side (that is, when the switching transistors Q1 and Q4 are synchronously on, the switching transistors Q2 and Q3 are synchronously off, and vice versa), so as to realize the power transmission from the second switching circuit on the AC side to the first switching circuit on the DC side.

[0098] When the bidirectional AC / DC converter operates in the inversion mode, for example, when it is necessary to supply power from the solar panel or the energy storage battery to the AC power grid, on the DC side, the switching transistors Q1, Q4 and the switching transistors Q2, Q3 alternately perform high-frequency on / off operations, so as to convert the direct current received on the DC side into high-frequency alternating current. At the same time, on the AC side, the control chip 7 controls the switching transistors Q5~Q8 to make them work synchronously with the high-frequency signal on the DC side. For example, during the positive half-cycle, Q5 and Q7 are kept constantly on, and Q6 and Q8 are alternately on and off; during the negative half-cycle, Q6 and Q8 are kept constantly on, and Q5 and Q7 are alternately on and off, so as to realize the power transmission from the first switching circuit on the DC side to the second switching circuit on the AC side.

[0099] During the above conversion process, the on / off frequency of the switching transistors on the DC side is the same as that of the switching transistors performing high-frequency on / off operations on the AC side, and a phase shift angle is formed between the signals of the switching transistors performing high-frequency on / off operations on the AC side and the signals of the switching transistors on the DC side. By adjusting the magnitude of this phase shift angle, for example, making the signals of the switching transistors on the AC side lead or lag the signals of the switching transistors on the DC side, the current direction on the inductance Ls is adjusted, so that the entire converter operates in the rectification or inversion mode.

[0100] To meet the overall size requirements of the photovoltaic energy storage module, the design parameters of the isolation transformer are optimized. According to E = 4.44fNQm, where E is the electromotive force, f is the frequency, N is the number of turns, and Qm is the magnetic flux. When the thickness of the isolation transformer becomes thinner, N decreases and Qm also decreases. By increasing the frequency f, the influence caused by the decrease of N and Qm can be compensated for.

[0101] After testing, when the operating frequency is in the range of 8KHz to 300KHz, the number of turns of the primary coil of the isolation transformer is set to 3 to 6 turns, the number of turns of the secondary coil is set to 9 to 18 turns, and the turns ratio is set to be between 2 and 4. The primary inductance is between 50μH and 1.5mH, and the secondary leakage inductance is between 5μH and 200μH. When the thickness of the transformer becomes thinner, the number of turns and the magnetic flux decrease. By increasing the frequency f, the influence brought by these changes can be compensated for, while keeping the height of the isolation transformer less than 17mm.

[0102] In addition, the bidirectional AC / DC converter also includes a second capacitor module, which is arranged between the second switching circuit and the AC power grid. This capacitor module is composed of 1 to 3 safety capacitors Cx2 with a height less than 17mm and is used for AC-side filtering of the bidirectional AC / DC converter. Since high-frequency operation reduces the requirement for the height of the safety capacitor, its height is also less than 17mm. Through this isolation-type transformer structure design of the bidirectional AC / DC converter, not only the efficient conversion between DC and AC is realized, but also the compact space and high-performance requirements of the photovoltaic energy storage module are met, and at the same time, the safety requirements of electrical isolation are satisfied.

[0103] Figure 8-2 The schematic diagram of the internal circuit structure of the bidirectional AC / DC converter adopting a non-isolation transformer structure is shown. In Figure 8-2 it, the circuit design of the bidirectional AC / DC converter adopts a non-isolation transformer structure, which is applicable to scenarios where electrical isolation is not required.

[0104] Among them, the bidirectional AC / DC converter includes a bidirectional full-bridge converter composed of four switching tubes Q1 - Q4 and an LC resonator. The DC side of the bidirectional full-bridge converter is electrically connected to the second end of the third switching element S3, and the LC resonator is arranged between the AC side of the bidirectional full-bridge converter and the AC power grid.

[0105] The switching tubes Q1 - Q4 can be MOSFETs, thyristors, etc., and are controlled by the control chip 7 to work in the rectification or inversion state. Similarly, by increasing the switching frequency of the switching tubes, the quality of the output-side waveform can be improved, and the height requirement of the safety capacitor Cx2 (used for AC-side filtering) can be reduced, making its height less than 17mm, and the number of uses of this safety capacitor is 1 - 3.

[0106] As described above, the above-mentioned numerous designs of the internal circuit structure of the AC / DC multi-directional conversion device are conducive to achieving a compact size of the AC / DC multi-directional conversion device, especially reducing its size in the thickness direction of the integrated photovoltaic energy storage module, so as to ensure that the extension height of the AC / DC multi-directional conversion device on the back of the solar panel does not exceed the back end face of its frame, and further enabling the entire photovoltaic energy storage module to be realized without increasing the external dimensions of the existing mainstream photovoltaic module (the overall thickness of the mainstream photovoltaic module is not greater than 36 mm, and the height of the back gap is not greater than 28 mm).

[0107] For those skilled in the art, various modifications and variations can be made to the embodiments disclosed above without departing from the scope or spirit of the present invention. Based on the practice of the present invention disclosed in this specification, other embodiments of the present invention will be obvious to those skilled in the art. This specification and the examples disclosed therein should be considered illustrative only, and the true scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated photovoltaic energy storage module, comprising a solar panel (1), an AC / DC multi-way conversion device (2) and an energy storage battery (3). The solar panel is provided with a frame (11) extending towards its back side, and the AC / DC multi-way conversion device and the energy storage battery are mounted on the back surface of the solar panel and the extending height does not exceed the back side end surface of the frame. The AC / DC multi-way conversion device (2) includes three groups of connection terminals, a plurality of voltage converters, a plurality of switching elements and a control chip (7). The three groups of connection terminals are respectively electrically connected to the solar panel, the energy storage battery and the AC power grid. Each switching element is arranged to electrically connect a corresponding one of the plurality of voltage converters to another converter among the plurality of voltage converters, or to a corresponding one of the three groups of connection terminals. And the control chip (7) is configured to: in different working modes of the integrated photovoltaic energy storage module, selectively turn on at least one of the plurality of switching elements to establish a voltage conversion path between corresponding two of the three groups of connection terminals by means of at least one of the plurality of voltage converters. Among them, The AC / DC multi-way conversion device (2) and the energy storage battery (3) are mounted on the back surface of the solar panel (1) through an integrated frame-shaped bracket (12) fixed to the frame within the frame (11). The energy storage battery (3) is composed of a plurality of battery cells, and at least a part of the plurality of battery cells is arranged in a single-layer tiled form. Wherein, the plurality of voltage converters include a first DC / DC converter (8), a second DC / DC converter (9) and a bidirectional AC / DC converter (10). Wherein, the input side of the first DC / DC converter (8) is electrically connected to the solar panel, the input side of the second DC / DC converter (9) is electrically connected to the energy storage battery, the AC side of the bidirectional AC / DC converter (10) is electrically connected to the AC power grid. The plurality of switching elements include first to third switching elements (S1, S2, S3). Wherein, the first switching element (S1) belongs to the first DC / DC converter (8), the second switching element (S2) belongs to the second DC / DC converter (9), and the third switching element (S3) belongs to the bidirectional AC / DC converter (10). Wherein, the control chip (7) is further configured to selectively turn on corresponding two of the first to third switching elements to realize different working modes of the integrated photovoltaic energy storage module by means of corresponding two of the first DC / DC converter (8), the second DC / DC converter (9) and the bidirectional AC / DC converter (10). The bidirectional AC / DC converter includes an inductor, an isolation transformer, a first switch circuit, and a second switch circuit. Among them, the input side of the first switch circuit is electrically connected to the DC side of the bidirectional AC / DC converter. The inductor is arranged between the secondary side of the isolation transformer and the input side of the second switch circuit. The output side of the second switch circuit is electrically connected to the AC side of the bidirectional AC / DC converter. Among them, the first and second switch circuits respectively adopt a full-bridge topology. The four bridge arms of the first switch circuit are respectively composed of single switch tubes. The first upper bridge arm and the first lower bridge arm of the second switch circuit are respectively composed of two switch tubes connected in series in a back-to-back manner. The second upper bridge arm and the second lower bridge arm of the second switch circuit are respectively composed of single capacitors. When the isolation transformer is within the frequency range of 8KHz to 300KHz, the number of turns of the primary coil of the isolation transformer is set to 3 to 6 turns, the number of turns of the secondary coil is set to 9 to 18 turns, the turns ratio is set to be between 2 and 4, the primary inductance is between 50μH and 1.5mH, the secondary leakage inductance is between 5μH and 200μH, and the height of the isolation transformer is set to be less than 17mm.

2. The integrated photovoltaic energy storage component according to claim 1, characterized in that The energy storage battery (3) includes a battery module composed of a combination of multiple blade batteries, multiple soft-pack batteries, or multiple solid-state batteries.

3. The integrated photovoltaic energy storage component according to claim 1, characterized in that, The integrated photovoltaic energy storage component further includes a battery management system (31) integrally provided in the AC / DC multi-way conversion device (2) or separately provided from the AC / DC multi-way conversion device.

4. The integrated photovoltaic energy storage component according to any one of claims 1 to 3, characterized in that, The working modes of the integrated photovoltaic energy storage component include a solar power supply mode, a DC charging mode, an AC charging mode, and a battery power supply mode. Among them, the control chip (7) is further configured as follows: In the solar power supply mode, the first and third switch elements (S1, S3) are turned on and the bidirectional AC / DC converter (10) operates in an inversion state, so as to convert the first direct current from the solar panel into the first alternating current for powering the AC grid by means of the first DC / DC converter (8) and the bidirectional AC / DC converter (10); In the DC charging mode, the first and second switch elements (S1, S2) are turned on, so as to convert the first direct current from the solar panel into the second direct current for charging the energy storage battery by means of the first DC / DC converter (8) and the second DC / DC converter (9); In the AC charging mode, the second and third switch elements (S2, S3) are turned on and the bidirectional AC / DC converter (10) operates in a rectification state, so as to convert the first alternating current from the AC grid into the second direct current for charging the energy storage battery by means of the bidirectional AC / DC converter (10) and the second DC / DC converter (9); and In the battery power supply mode, the second and third switch elements (S2, S3) are turned on and the bidirectional AC / DC converter (10) operates in an inversion state, so as to convert the second direct current from the energy storage battery into the first alternating current for powering the AC grid by means of the second DC / DC converter (9) and the bidirectional AC / DC converter (10).

5. The integrated photovoltaic energy storage module according to any one of claims 1 to 3, characterized in that, The first and second DC / DC converters are each implemented as any one of a Boost boost circuit, a Buck buck circuit, and a Boost-Buck buck-boost circuit.

6. The integrated photovoltaic energy storage component according to claim 5, characterized in that, The Boost-Buck buck-boost circuit includes a first switching transistor (Q1) disposed at the input side of the corresponding DC / DC converter, a second switching transistor (Q2) disposed at the output side of the corresponding DC / DC converter, and a storage inductor (L) disposed between the first switching transistor (Q1) and the second switching transistor (Q2). Wherein, the control chip (7) is configured to control the duty cycles of the first and second switching transistors based on the output voltage of the solar panel and the charging voltage of the energy storage battery, so that the corresponding DC / DC converter operates in a boost mode or a buck mode.

7. The integrated photovoltaic energy storage module according to any one of claims 1 to 3, characterized in that The first and second DC / DC converters each include a first capacitor module, and the first capacitor module is composed of at least one electrolytic capacitor (C1-C4) and at least one chip capacitor (C6-C9).

8. The integrated photovoltaic energy storage component according to claim 7, characterized in that, The capacitance of each electrolytic capacitor is 800 μF - 3000 μF, the capacitance of each chip capacitor is 1 - 10 μF, and the diameter of each electrolytic capacitor is less than 17 mm.

9. The integrated photovoltaic energy storage component according to any one of claims 1 to 3, characterized in that, The bidirectional AC / DC converter further includes a second capacitor module disposed between the second switching circuit and the AC power grid, and the second capacitor module is composed of 1 to 3 safety capacitors (Cx2) with a height less than 17 mm.

10. The integrated photovoltaic energy storage module according to any one of claims 1 to 3, characterized in that, The bidirectional AC / DC converter includes a bidirectional full-bridge converter composed of four switching transistors and an LC resonator. The DC side of the bidirectional full-bridge converter is electrically connected to the second end of the third switching element (S3), and the LC resonator is disposed between the AC side of the bidirectional full-bridge converter and the AC power grid.

11. The integrated photovoltaic energy storage module according to claim 10, wherein, The bidirectional AC / DC converter further includes a third capacitor module disposed between the LC resonator and the AC power grid, and the third capacitor module is composed of 1 to 3 safety capacitors (Cx2) with a height less than 17 mm.

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