High-low voltage conversion device and energy system

Abstract

The utility model provides a high-low voltage conversion device and an energy system. The high-low voltage conversion device comprises a bidirectional buck-boost conversion circuit which comprises a low-voltage side and a high-voltage side; wherein the high-low voltage conversion device has a first connection mode and a second connection mode; in the first connection mode, the low-voltage side of the high-low voltage conversion device is connected to a low-voltage battery, and the high-voltage side of the high-low voltage conversion device is connected to a high-voltage battery interface of a first power conversion device; and in the second connection mode, the high-voltage side of the high-low voltage conversion device is connected to a high-voltage battery, and the low-voltage side of the high-low voltage conversion device is connected to a low-voltage battery interface of a second power conversion device. The compatibility between the energy storage inverter and batteries with different voltage levels can be improved to a certain extent by using the high-low voltage conversion device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and in particular to a high-low voltage conversion device and an energy system. BACKGROUND

[0002] With the rapid development of renewable energy, energy storage batteries play an increasingly important role in power systems. Energy storage batteries are usually connected with power conversion devices to realize energy conversion between the batteries and the power grid.

[0003] However, the current power conversion devices are usually designed only for high-voltage batteries or only for low-voltage batteries, which leads to the fact that these power conversion devices can only be used with batteries that match them, and the compatibility is poor. CONTENT OF THE UTILITY MODEL

[0004] The embodiments of the present application provide a high-low voltage conversion device and an energy system, which can improve the compatibility between the power conversion device and the batteries of different voltage levels to some extent.

[0005] The embodiments of the present application provide a high-low voltage conversion device, comprising: a bidirectional buck-boost conversion circuit having a low-voltage side and a high-voltage side; wherein the high-low voltage conversion device has a first connection mode and a second connection mode; in the first connection mode, the low-voltage side of the bidirectional buck-boost conversion circuit is connected to a low-voltage battery, and the high-voltage side of the bidirectional buck-boost conversion circuit is connected to a high-voltage battery interface of a first power conversion device; in the second connection mode, the high-voltage side of the bidirectional buck-boost conversion circuit is connected to a high-voltage battery, and the low-voltage side of the bidirectional buck-boost conversion circuit is connected to a low-voltage battery interface of a second power conversion device.

[0006] In some embodiments, the high-low voltage conversion device further comprises a control unit; in the first connection mode, the control unit is connected to a control module of the first power conversion device through a communication bus; or in the second connection mode, the control unit is connected to a control module of the second power conversion device through a communication bus.

[0007] In some embodiments, the high-low voltage conversion device further has a third connection mode; in the third connection mode, the low-voltage side of the bidirectional buck-boost conversion circuit is connected to a low-voltage battery, and the high-voltage side of the bidirectional buck-boost conversion circuit is connected to a DC bus of a third power conversion device.

[0008] In some embodiments, the high-low voltage conversion device further comprises a control unit; in the third connection mode, the control unit is connected to a control module of the third power conversion device through a communication bus.

[0009] In some embodiments, the low-voltage battery or the high-voltage battery connected with the high-low voltage conversion device is equipped with a battery management module, and the battery management module is connected to the communication bus.

[0010] In some embodiments, the bidirectional buck-boost conversion circuit includes a bidirectional dual active bridge circuit or a bidirectional CLLC circuit.

[0011] In some embodiments, the high-low voltage conversion device further includes a housing for accommodating the bidirectional buck-boost conversion circuit, the housing has a low-voltage side interface connected to the low-voltage side of the bidirectional buck-boost conversion circuit, and a high-voltage side interface connected to the high-voltage side of the bidirectional buck-boost conversion circuit, wherein the interface types of the low-voltage side interface and the high-voltage side interface are different.

[0012] The embodiments of the present application provide an energy system including the high-low voltage conversion device of any of the above embodiments, and the high-low voltage conversion device is connected with a low-voltage battery and a first power conversion device having a high-voltage battery interface based on a first connection mode.

[0013] The embodiments of the present application provide an energy system including the high-low voltage conversion device of any of the above embodiments, and the high-low voltage conversion device is connected with a high-voltage battery and a second power conversion device having a low-voltage battery interface based on a second connection mode.

[0014] The embodiments of the present application provide an energy system including the high-low voltage conversion device of any of the above embodiments, and the high-low voltage conversion device is connected with a low-voltage battery and a third power conversion device based on a third connection mode.

[0015] In the plurality of embodiments provided by the present application, the high-low voltage conversion device includes a bidirectional buck-boost conversion circuit having a low-voltage side and a high-voltage side. Moreover, the high-low voltage conversion device has a first connection mode and a second connection mode. In the first connection mode, the low-voltage side of the high-low voltage conversion device is connected to a low-voltage battery, and the high-voltage side of the high-low voltage conversion device is connected to a high-voltage battery interface of a first power conversion device. In the second connection mode, the high-voltage side of the high-low voltage conversion device is connected to a high-voltage battery, and the low-voltage side of the high-low voltage conversion device is connected to a low-voltage battery interface of a second power conversion device. Thus, when the voltage level of the battery and the voltage level supported by the power conversion device do not match, the power conversion device and the battery can be connected through the high-low voltage conversion device to achieve compatible operation of the power conversion device and the battery, and to a certain extent, improve the compatibility between the power conversion device and the battery of different voltage levels. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only need to explain the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on the provided drawings.

[0017] Figure 1a The schematic diagram of the connection relationship between the first power conversion device and the high-voltage battery in the related art for an embodiment of the present application is provided.

[0018] Figure 1b The schematic diagram of the connection relationship between the second power conversion device and the low-voltage battery in the related art for an embodiment of the present application is provided.

[0019] Figure 2 The schematic diagram of the connection relationship of the high-low voltage conversion device in the first connection mode for an embodiment of the present application is provided.

[0020] Figure 3 The schematic diagram of the connection relationship of the high-low voltage conversion device in the second connection mode for an embodiment of the present application is provided.

[0021] Figure 4 The schematic diagram of the bidirectional dual-active bridge circuit for an embodiment of the present application is provided.

[0022] Figure 5 The schematic diagram of the bidirectional CLLC circuit for an embodiment of the present application is provided.

[0023] Figure 6a The schematic diagram of the communication relationship between the first power conversion device and the high-low voltage conversion device for an embodiment of the present application is provided.

[0024] Figure 6b The schematic diagram of the communication relationship between the second power conversion device and the high-low voltage conversion device for an embodiment of the present application is provided.

[0025] Figure 7 The schematic diagram of the connection relationship of the high-low voltage conversion device in the third connection mode for an embodiment of the present application is provided.

[0026] Figure 8 The schematic diagram of the communication relationship between the third power conversion device and the high-low voltage conversion device for an embodiment of the present application is provided.

[0027] Figure 9a The schematic diagram of the communication relationship between the first power conversion device, the high-low voltage conversion device and the battery pack for an embodiment of the present application is provided.

[0028] Figure 9b A schematic diagram of a communication relationship of a second power conversion device, a high-low voltage conversion device and a battery pack provided for an embodiment of the present application.

[0029] Figure 9c A schematic diagram of a communication relationship of a third power conversion device, a high-low voltage conversion device and a battery pack provided for an embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0031] In the description of the embodiments of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0032] In the related art, the voltage ranges of high-voltage batteries and low-voltage batteries are quite different, which makes the types of components in the power conversion device adapted to high-voltage batteries and the types of components in the power conversion device adapted to low-voltage batteries quite different. Therefore, some power conversion devices in the related art only support access to high-voltage batteries or only support access to low-voltage batteries.

[0033] Please refer to Figure 1a and Figure 1b The power conversion device can be an energy storage inverter. Some energy storage inverters only have a high-voltage battery interface for accessing high-voltage batteries. Some other energy storage inverters only have a low-voltage battery interface for accessing low-voltage batteries. Among them, the battery voltage range that can be matched by the energy storage inverter supporting access to high-voltage batteries is about 100V to 800V. The battery voltage range that can be matched by the energy storage inverter supporting access to low-voltage batteries is about 40V to 60V.

[0034] If two sets of circuits supporting high-voltage batteries and supporting low-voltage batteries are integrated in the same power conversion device, it may cause redundancy of the circuit of the power conversion device, which increases the cost of the power conversion device to a certain extent. Moreover, the development cost and difficulty of the power conversion device adapted to two different voltage levels of batteries are relatively large.

[0035] To this end, the application provides a high-low voltage conversion device and an energy system. The high-low voltage conversion device includes a bidirectional buck-boost conversion circuit having a low-voltage side and a high-voltage side. When the voltage level of a battery does not match the battery voltage level supported by a power conversion device, connecting the battery and the power conversion device through the high-low voltage conversion device can enable the power conversion device to operate compatibly with the battery, thereby improving the compatibility between the power conversion device and the battery of different voltage levels to a certain extent.

[0036] Referring to Figure 2 and Figure 3 , the application provides a high-low voltage conversion device. The high-low voltage conversion device includes a bidirectional buck-boost conversion circuit. The bidirectional buck-boost conversion circuit has a low-voltage side and a high-voltage side.

[0037] The bidirectional buck-boost conversion circuit is used to implement conversion between direct current of different voltage levels and direct current. Specifically, the bidirectional buck-boost conversion circuit can boost the voltage on the low-voltage side to the high-voltage side. In addition, the bidirectional buck-boost conversion circuit can also buck the voltage on the high-voltage side to the low-voltage side.

[0038] In some embodiments, the bidirectional buck-boost conversion circuit includes a dual active bridge (DAB) circuit or a bidirectional CLLC (Capacitor-Inductor-Inductor-Capacitor) circuit.

[0039] The dual active bridge circuit is a circuit structure used to implement bidirectional conversion of high-low voltage electric energy. Referring to Figure 4 , the dual active bridge circuit can be constructed by four active switches, which can be connected in a bridge structure to achieve voltage conversion and bidirectional current flow. The dual active bridge circuit has the advantages of high efficiency, fast response, and good control accuracy, and is suitable for application scenarios where the high-low voltage conversion device needs frequent voltage conversion and bidirectional energy flow.

[0040] The bidirectional CLLC circuit is another circuit structure used to implement bidirectional conversion of high-low voltage electric energy. Referring to Figure 5 , the bidirectional CLLC circuit can be a resonant circuit composed of an inductor (L) and a capacitor (C). The bidirectional CLLC circuit has excellent electric energy conversion characteristics and resonance regulation capability, and can provide high-quality electric energy for energy storage inverters.

[0041] The high-low voltage conversion device can be used to connect a power conversion device and a battery. The power conversion device can include a first power conversion device and a second power conversion device. The battery can include a high-voltage battery and a low-voltage battery.

[0042] The first power conversion device has a high-voltage battery interface. For example, the first power conversion device can be an energy storage converter with a high-voltage battery interface.

[0043] The second power conversion device has a low-voltage battery interface. For example, the second power conversion device can be an energy storage converter with a low-voltage battery interface.

[0044] An energy storage inverter refers to a device for converting direct current power stored in an energy storage device (such as a battery) into alternating current power, or converting alternating current power into direct current power, to achieve bidirectional flow and management of electrical energy. In some embodiments, the energy storage inverter can include an inverter circuit to achieve electrical energy conversion between direct current and alternating current.

[0045] The high-low voltage conversion device, the power conversion device, and the battery have a first connection mode and a second connection mode.

[0046] Referring to Figure 2 , in the first connection mode, the low-voltage side of the bidirectional buck-boost conversion circuit of the high-low voltage conversion device is connected to the low-voltage battery, and the high-voltage side of the bidirectional buck-boost conversion circuit of the high-low voltage conversion device is connected to the high-voltage battery interface of the first power conversion device.

[0047] Specifically, through the first connection mode, the low-voltage battery can exchange energy with the high-voltage battery interface of the first power conversion device through the bidirectional buck-boost conversion circuit.

[0048] For example, in the case where the battery is a low-voltage battery and the first power conversion device is an energy storage inverter with only a high-voltage battery interface, the energy storage inverter, the high-low voltage conversion device, and the low-voltage battery can be connected through the first connection mode. That is, the high-voltage battery interface of the energy storage inverter can be connected to the high-voltage side of the bidirectional buck-boost conversion circuit of the high-low voltage conversion device, and the low-voltage side of the bidirectional buck-boost conversion circuit can be connected to the low-voltage battery.

[0049] Correspondingly, when the low-voltage battery is discharging, the voltage of the low-voltage battery can be boosted by the bidirectional buck-boost conversion circuit of the high-low voltage conversion device and provided to the energy storage inverter. When charging the low-voltage battery, the voltage provided by the high-voltage battery interface of the energy storage inverter can also be stepped down by the bidirectional buck-boost conversion circuit of the high-low voltage conversion device and provided to the low-voltage battery.

[0050] Referring to Figure 3 , in the second connection mode, the high-voltage side of the high-low voltage conversion device is connected to the high-voltage battery, and the low-voltage side of the high-low voltage conversion device is connected to the low-voltage battery interface of the second power conversion device.

[0051] Specifically, through the second connection mode, the high-voltage battery can exchange energy with the low-voltage battery interface of the second power conversion device through the bidirectional buck-boost conversion circuit.

[0052] For example, when the battery is a high-voltage battery and the second power conversion device is only provided with a low-voltage battery interface, the energy storage inverter, the high-low voltage conversion device and the high-voltage battery can be connected through the second connection mode. That is, the low-voltage battery interface of the energy storage inverter can be connected to the low-voltage side of the bidirectional buck-boost conversion circuit of the high-low voltage conversion device, and the high-voltage side of the bidirectional buck-boost conversion circuit can be connected to the high-voltage battery.

[0053] Correspondingly, when the high-voltage battery is discharging, the voltage of the high-voltage battery can be provided to the energy storage inverter through the bidirectional buck-boost conversion circuit of the high-low voltage conversion device. When charging the high-voltage battery, the voltage provided by the low-voltage battery interface of the energy storage inverter can also be provided to the high-voltage battery through the bidirectional buck-boost conversion circuit of the high-low voltage conversion device.

[0054] In summary, through the first connection mode and the second connection mode described above, the high-low voltage conversion device can realize the compatible operation of the power conversion device and the battery of different voltage levels when the battery voltage level supported by the power conversion device does not match the battery voltage level. Specifically, when a low-voltage battery needs to be used in actual application but the power conversion device is the first power conversion device, the first connection mode can be used to make the low-voltage battery work with the first power conversion device through the cooperation of the high-low voltage conversion device. When a high-voltage battery needs to be used, the second connection mode can be used to make the high-voltage battery work with the second power conversion device through the cooperation of the high-low voltage conversion device. Therefore, a single type of power conversion device can be adapted to batteries of multiple voltage levels, which significantly improves the adaptability and flexibility of the system, reduces the overall cost of the system, and simplifies the research and production process of the power conversion device.

[0055] Moreover, since the compatible operation of the power conversion device and the battery of different voltage levels is realized through the high-low voltage conversion device, when the energy storage power station newly adds a battery, it is not necessary to replace a large number of power conversion devices when purchasing a battery of different voltage levels, thereby reducing the cost of the energy storage power station.

[0056] In addition, the power conversion device in the embodiments of the present application can also be connected to a power grid. The power grid can be a single-phase power grid or a three-phase power grid. The embodiments are not specifically limited herein.

[0057] Please refer to Figure 6a In some embodiments, the high-low voltage conversion device further comprises a control unit, and in the first connection mode, the control unit is connected to the control module of the first power conversion device through a communication bus. Alternatively, please refer to Figure 6b In the second connection mode, the control unit is connected to the control module of the second power conversion device through a communication bus.

[0058] The control unit is a component for real-time monitoring and adjusting the voltage, current and operating state inside the high-low voltage conversion device. For example, the control unit can include a separate circuit board or control chip for controlling the semiconductor switches in the bidirectional buck-boost conversion circuit to adjust the operating state of the bidirectional buck-boost conversion circuit. Of course, the control unit also determines the operating state of the high-low voltage conversion device by obtaining relevant sensor information. The present application does not make specific limitations here.

[0059] The control module of the first power conversion device is a unit for coordinating and managing the overall operating state of the first power conversion device. For example, the first power conversion device is an energy storage inverter, and the control module can be used to adjust the operating state of the inverter circuit of the energy storage inverter to achieve management of the flow direction of electrical energy.

[0060] The control module of the second power conversion device is a unit for coordinating and managing the overall operating state of the second power conversion device. For example, the second power conversion device is an energy storage inverter, and the control module can be used to adjust the operating state of the inverter circuit of the energy storage inverter to achieve management of the flow direction of electrical energy.

[0061] The control module of the first power conversion device or the second power conversion device needs to maintain real-time communication with the control unit of the high-low voltage conversion device to achieve coordinated work and improve the efficiency of electrical energy conversion of the system.

[0062] The communication bus is a signal transmission channel for connecting the control unit and the control module of the energy storage inverter. For example, the communication bus can use CAN bus or RS485 bus to transmit command information, operating data and fault diagnosis information.

[0063] The control unit of the high-low voltage conversion device and the control module of the power conversion device are connected through the communication bus, which can achieve the coordinated work of the high-low voltage conversion device and the power conversion device. Specifically, through the communication bus, the control unit can receive the instructions issued by the control module of the power conversion device in real time, and adjust the operating state of the bidirectional buck-boost conversion circuit according to the needs of the power conversion device, to efficiently cooperate with the energy storage inverter to achieve energy conversion.

[0064] Please refer to Figure 7 In some embodiments, the high-low voltage conversion device also has a third connection mode; in the third connection mode, the low-voltage side of the bidirectional buck-boost conversion circuit is connected to the low-voltage battery, and the high-voltage side of the bidirectional buck-boost conversion circuit is connected to the DC bus of the third power conversion device.

[0065] The third power conversion device can be a device for realizing power conversion. The third power conversion device can be a photovoltaic inverter. The photovoltaic inverter is a device for converting direct current generated by a photovoltaic module into alternating current that can be connected to a grid or used by a load. For example, the direct current bus of the photovoltaic inverter can receive power generated by the photovoltaic module, and convert the direct current into alternating current through an inverter circuit inside the photovoltaic inverter.

[0066] However, some third power conversion devices similar to the photovoltaic inverter do not have a battery interface for connecting a battery. This results in relatively single external devices connected to some third power conversion devices. For example, when building a photovoltaic energy storage integrated system, a storage inverter for connecting a battery needs to be arranged in the photovoltaic energy storage integrated system at the same time that the photovoltaic inverter is arranged in the photovoltaic energy storage integrated system, so that the photovoltaic module and the battery can be connected to the entire system. This increases the complexity and cost of the photovoltaic integrated system to some extent. Therefore, connecting the low-voltage battery, the high-low voltage conversion device, and the photovoltaic inverter through the third connection mode can add the function of connecting the battery to the third power conversion device without changing the design of the third power conversion device, and can improve the compatibility and expandability of the third power conversion device to some extent.

[0067] Specifically, the high-voltage side of the bidirectional step-up and step-down conversion circuit of the high-low voltage conversion device can be connected to the direct current bus of the photovoltaic inverter, and the low-voltage side of the bidirectional step-up and step-down conversion circuit can be connected to the low-voltage battery. When the low-voltage battery needs to discharge to the direct current bus of the photovoltaic inverter, the high-low voltage conversion device can boost the low voltage output by the low-voltage battery to the high voltage required by the direct current bus of the photovoltaic inverter. When the photovoltaic inverter needs to charge the low-voltage battery, the high-low voltage conversion device can step down the high voltage of the direct current bus of the photovoltaic inverter to provide the low-voltage battery with low voltage. In this way, the matching operation of the low-voltage battery and the photovoltaic inverter can be realized.

[0068] Please refer to Figure 8 In some embodiments, in the third connection mode, the control unit of the high-low voltage conversion device is connected to the control module of the third power conversion device through the communication bus.

[0069] In this embodiment, the control unit of the high-low voltage conversion device can also be connected to the control module of the third power conversion device through the communication bus, to realize the cooperative work of the high-low voltage conversion device and the third power conversion device. Specifically, through the communication bus, the control unit can receive instructions issued by the control module of the third power conversion device in real time, and adjust the working state of the bidirectional step-up and step-down conversion circuit according to the requirements of the third power conversion device, to efficiently cooperate with the third power conversion device to realize power conversion.

[0070] Please refer to Figure 9a , Figure 9b andFigure 9c In some embodiments, the low-voltage battery or the high-voltage battery connected to the high-low voltage conversion device is equipped with a battery management module, and the battery management module is connected to the communication bus.

[0071] The battery management module is a component for monitoring and managing the state of the battery. The battery to which the battery management module is directed can be a high-voltage battery or a low-voltage battery. The battery management module and its corresponding low-voltage battery or high-voltage battery can form a battery pack.

[0072] The battery management module is connected to the communication bus, and after transmitting the state information of the battery to the power conversion device, the control module of the power conversion device can issue a working state adjustment instruction to the high-low voltage conversion device according to the state information of the battery, so as to coordinate the cooperation between the battery and the power conversion device. For example, the battery management module can transmit the real-time state data (such as voltage, current, temperature) of the battery to the control module of the power conversion device through the communication bus, and the control module can issue the target voltage required by the high-low voltage conversion device to the control unit of the high-low voltage conversion device according to the real-time state data of the battery. The control unit of the high-low voltage conversion device can control the output target voltage of the bidirectional buck-boost conversion circuit to meet the needs of the power conversion device.

[0073] In some embodiments, the high-low voltage conversion device further comprises: a housing for accommodating the bidirectional buck-boost conversion circuit; the housing has a low-voltage side interface connected to the low-voltage side of the bidirectional buck-boost conversion circuit, and a high-voltage side interface connected to the high-voltage side of the bidirectional buck-boost conversion circuit; wherein the interface types of the low-voltage side interface and the high-voltage side interface are different.

[0074] The housing is a shell structure for accommodating the bidirectional buck-boost conversion circuit, for protecting and supporting the bidirectional buck-boost conversion circuit inside the high-low voltage conversion device.

[0075] The low-voltage side interface and the high-voltage side interface of the housing provide interfaces for the high-low voltage conversion device to connect with the battery and the inverter.

[0076] The interface types of the low-voltage side interface and the high-voltage side interface are different. Specifically, the low-voltage side interface and the high-voltage side interface can differ in physical structure, size, connection method, etc., thereby reducing the risk of user misoperation to a certain extent during connection. For example, the low-voltage side interface can adopt a smaller size interface design to adapt to the needs of low voltage and low current. Correspondingly, the high-voltage side interface can adopt a larger size plug design to adapt to the needs of high voltage and large current. Alternatively, the low-voltage side interface and the high-voltage side interface can also be distinguished by color coding or shape identification, etc. This embodiment is not limited specifically herein.

[0077] The embodiment of the present application provides an energy system, comprising the high-low voltage conversion device in any of the above embodiments, and the high-low voltage conversion device is connected with the low-voltage battery and the first power conversion device with the high-voltage battery interface through the first connection mode.

[0078] The first power conversion device can be an energy storage inverter with the high-voltage battery interface, and the alternating current side of the energy storage inverter can be used for connecting a load or connecting a power grid. The embodiment is not limited here.

[0079] The related description of the energy system can refer to other embodiments of the present application, and the embodiment is not limited here.

[0080] The embodiment of the present application provides an energy system, comprising the high-low voltage conversion device in any of the above embodiments, and the high-low voltage conversion device is connected with the high-voltage battery and the second power conversion device with the low-voltage battery interface through the second connection mode.

[0081] The second power conversion device can be an energy storage inverter with the low-voltage battery interface, and the alternating current side of the energy storage inverter can be used for connecting a load or connecting a power grid. The embodiment is not limited here.

[0082] The related description of the energy system can refer to other embodiments of the present application, and the embodiment is not limited here.

[0083] The embodiment of the present application provides an energy system, comprising the high-low voltage conversion device in any of the above embodiments, and the high-low voltage conversion device is connected with the low-voltage battery and the third power conversion device through the third connection mode.

[0084] The third power conversion device can be a photovoltaic inverter, and the alternating current side of the photovoltaic inverter can be used for connecting a load or connecting a power grid. The embodiment is not limited here.

[0085] The related description of the energy system can refer to other embodiments of the present application, and the embodiment is not limited here.

[0086] It can be understood that, in the above embodiments, if the circuits, modules, units and the like connected with each other can have the transmission of electrical signals or data, it should be understood as "electrical connection", "communication connection" and the like.

[0087] It can be understood that the specific examples herein are only to help those skilled in the art better understand the present application, and not to limit the scope of the present application.

[0088] It can be understood that, in various embodiments in the present application, the size of the serial number of each process does not mean the execution order, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the present application.

[0089] It can be understood that the various embodiments described in the present application can be implemented independently or in combination, and the present application is not limited thereto.

[0090] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for describing particular embodiments only and is not intended to be limiting of the application. All publications, patent applications, patents, and other references mentioned in this application are incorporated by reference. As used in this application, the term "and / or" includes any and all combinations of one or more of the associated listed items. Singular articles, such as "a", "an" and "the", as used in the application and the appended claims, can also include plural articles unless the context clearly indicates otherwise.

[0091] Those skilled in the art can understand that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0092] Those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0093] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. For example, the above-described device embodiments are only schematic, and the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0094] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, i.e. they can be located in one place or distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0095] The above merely provides the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high-low voltage conversion device, characterized by, Comprising: a bidirectional buck-boost converter circuit having a low voltage side and a high voltage side; wherein the high-low voltage conversion device has a first connection mode and a second connection mode; in the first connection mode, the low voltage side of the bidirectional buck-boost converter circuit is configured to be connected to a low voltage battery, and the high voltage side of the bidirectional buck-boost converter circuit is configured to be connected to a high voltage battery interface of a first power conversion device; in the second connection mode, the high voltage side of the bidirectional buck-boost converter circuit is configured to be connected to a high voltage battery, and the low voltage side of the bidirectional buck-boost converter circuit is configured to be connected to a low voltage battery interface of a second power conversion device.

2. The high-low voltage conversion device of claim 1, wherein, The high-low voltage conversion device further comprises: a control unit; in the first connection mode, the control unit is connected to a control module of the first power conversion device through a communication bus; or, in the second connection mode, the control unit is connected to a control module of the second power conversion device through a communication bus.

3. The high-low voltage conversion device of claim 1, wherein, The high-low voltage conversion device further has a third connection mode; in the third connection mode, the low voltage side of the bidirectional buck-boost converter circuit is connected to a low voltage battery, and the high voltage side of the bidirectional buck-boost converter circuit is connected to a DC bus of a third power conversion device.

4. The high-low voltage conversion device of claim 3, wherein, The high-low voltage conversion device further comprises: a control unit; in the third connection mode, the control unit is connected to a control module of the third power conversion device through a communication bus.

5. The high-low voltage conversion device according to claim 2 or 4, wherein a low voltage battery or a high voltage battery connected to the high-low voltage conversion device is equipped with a battery management module, and the battery management module is connected to the communication bus.

6. The high-low voltage conversion device according to any one of claims 1 to 4, characterized in that, The bidirectional buck-boost converter circuit comprises a bidirectional dual active bridge circuit or a bidirectional CLLC circuit.

7. The high-low voltage conversion device according to any one of claims 1 to 4, characterized in that, The high-low voltage conversion device further comprises: a housing for accommodating the bidirectional buck-boost converter circuit; the housing has a low voltage side interface connected to the low voltage side of the bidirectional buck-boost converter circuit, and a high voltage side interface connected to the high voltage side of the bidirectional buck-boost converter circuit; wherein the interface types of the low voltage side interface and the high voltage side interface are different.

8. An energy system characterized by, Comprising: the high-low voltage conversion device according to any one of claims 1 to 7, which is connected to a low voltage battery and a first power conversion device having a high voltage battery interface based on the first connection mode.

9. An energy system characterized by, Comprising: the high-low voltage conversion device according to any one of claims 1 to 7, which is connected to a high voltage battery and a second power conversion device having a low voltage battery interface based on the second connection mode.

10. An energy system characterized by, Comprising: the high-low voltage conversion device according to any one of claims 3 to 7, which is connected to a low voltage battery and a third power conversion device based on the third connection mode.

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