New energy storage sub-module and operation method thereof, energy storage system and operation method thereof

Abstract

The invention relates to a new energy storage sub-module, an operation method of the new energy storage sub-module, an energy storage valve, an energy storage system and an operation method of the energy storage system. A new energy storage sub-module comprising a direct current bus, a power module, an energy storage module, a first converter and a new energy assembly is constructed, and the new energy assembly is connected to the energy storage system to operate in the form of the new energy storage sub-module. According to the scheme, the new energy assemblies are arranged in the new energy storage sub-modules in the distributed mode, the new energy assemblies are modularized, good flexibility is achieved, the influence of single faults of the new energy assemblies on the new energy grid-connected system can be reduced, and therefore the system availability rate of the new energy grid-connected system is effectively increased.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a new energy storage submodule and an operating method thereof, an energy storage valve, an energy storage system and an operating method thereof. Background Art

[0002] With the development of new energy technology and energy storage technology, the grid-connected operation of new energy power generation modules and energy storage systems has gradually developed. Among various types of new energy power generation modules, new energy power generation has been widely used due to its advantages such as clean and pollution-free, short construction period, long service life and low maintenance cost. The new energy grid-connected system generally converts the DC power output by the new energy components into AC power through a new energy inverter, and then boosts it to the grid voltage through a transformer and transmits it to the AC grid.

[0003] However, in the related art, when a new energy component fails, the new energy grid-connected system will be shut down, resulting in low system availability of the new energy grid-connected system. Summary of the invention

[0004] Based on this, it is necessary to provide a new energy storage submodule and its operating method, a storage valve, an energy storage system and its operating method to improve the system availability of the new energy grid-connected system.

[0005] An embodiment of the present application provides a new energy storage sub-module, including a DC bus, a power module, an energy storage module, a first converter and a new energy component, wherein the energy storage module is connected to the power module via the DC bus, the first converter is connected to the DC bus, and the new energy component is connected to the first converter.

[0006] In the above scheme, in the new energy grid-connected system, the new energy components are distributedly arranged in each submodule, and a new energy storage submodule including a DC bus, a power module, an energy storage module, a first converter and new energy components is constructed, and the new energy components are connected to the energy storage system in the form of a new energy storage submodule for operation. Through this scheme, the new energy components are distributedly arranged in each new energy storage submodule, and the new energy components are modularized, which has good flexibility and can reduce the impact of single failures of new energy components on the new energy grid-connected system. That is, when a single new energy component fails, the new energy storage submodule where the failed new energy component is located can be removed, which will not have a significant impact on the operation of other new energy components, and increase the proportion of the operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0007] In some embodiments, the new energy storage submodule further includes a second converter, which is disposed between the DC bus and the energy storage module and is connected to the DC bus and the energy storage module respectively.

[0008] In the above solution, a second converter is further provided between the DC bus and the energy storage module, and the DC voltage conversion during the charging and discharging process can be achieved through the second converter to meet the charging and discharging requirements of the energy storage module.

[0009] In some embodiments, the second converter includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

[0010] In the above solution, the second converter can be set as a bidirectional non-isolated DC converter or a bidirectional isolated DC converter, which can be selected based on the actual scenario, and has high setting flexibility.

[0011] In some embodiments, the new energy storage submodule further includes an insulating support component, and the new energy component is disposed on the insulating support component.

[0012] In the above solution, the new energy component is arranged on the insulating support component, and voltage isolation is performed through the insulating support component to improve the operating reliability of the new energy component.

[0013] In some embodiments, the first converter comprises a non-isolated DC converter.

[0014] In the above scheme, when the new energy component is voltage-isolated by the insulating support component, the first converter between the new energy component and the DC bus directly adopts a non-isolated DC converter, which can effectively reduce costs.

[0015] In some embodiments, the first converter comprises an isolated DC converter.

[0016] In the above scheme, the first converter between the new energy component and the DC bus adopts an isolated DC converter. The high-voltage isolation of the new energy component can be achieved through the isolated converter, so that the new energy component can be erected without going through an insulating support component, thereby improving the convenience of erecting the new energy storage sub-module.

[0017] In some embodiments, the new energy storage submodule further includes a third converter, which is disposed between the DC bus and the power module and is connected to the DC bus and the power module respectively.

[0018] In the above scheme, the energy storage module is connected to the third converter via a DC bus, so that the new energy component is directly connected between the third converter and the energy storage module. The electric energy generated by the new energy component can be transmitted to the energy storage module without passing through the third converter, which can effectively improve the efficiency of electric energy transmission.

[0019] In some embodiments, the new energy component comprises a photovoltaic component.

[0020] In the above scheme, the new energy components specifically adopt photovoltaic components, and the power generation and operation stability of the new energy storage sub-module.

[0021] An embodiment of the present application also provides an operating method based on the above-mentioned new energy energy storage sub-module, including: when the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; when the electric energy supply conditions are met, the electric energy output by the new energy component is converted by the first converter and the power module and then transmitted to the power grid for load power supply.

[0022] In the above scheme, the electric energy generated by the new energy components can be transmitted to the energy storage module for storage according to actual conditions, and / or transmitted to the power grid to power the load, thereby reducing the waste of electric energy generated by the new energy components and improving the electric energy utilization rate of the new energy components.

[0023] In some embodiments, the operating method also includes: obtaining the output electrical parameters of the new energy component; determining the target output voltage of the new energy component when operating at maximum power based on the output electrical parameters; and controlling the operation of the first converter based on the output electrical parameters and the target output voltage.

[0024] The above scheme can be combined with the output electrical parameters of the new energy components to maintain the new energy components running at maximum power and improve the operating efficiency of the new energy components.

[0025] In some embodiments, the output electrical parameters include an output voltage and an output current, and determining the target output voltage of the new energy component when it operates at maximum power based on the output electrical parameters includes: performing maximum power point tracking control based on the output voltage and the output current to determine the target output voltage of the new energy component when it operates at maximum power; controlling the operation of the first converter based on the output electrical parameters and the target output voltage includes: controlling the operation of the first converter based on the output voltage and the target output voltage.

[0026] The above scheme can combine the output current and output voltage of the new energy component to perform maximum power point tracking control, thereby determining the target output voltage when the new energy component is running at maximum power, and improving the control accuracy of the new energy component running at maximum power.

[0027] In some embodiments, controlling the operation of the first converter according to the output voltage and the target output voltage includes: determining an output voltage difference according to comparison between the output voltage and the target output voltage; performing proportional-integral adjustment according to the output voltage difference to determine a first target duty cycle; performing pulse width modulation according to the first target duty cycle to generate a first switching signal and send it to the first converter.

[0028] The above scheme combines the output voltage and the target output voltage to perform proportional-integral regulation, and performs pulse width modulation on the result of the proportional-integral regulation, thereby determining the first switching signal required for the operation of the first converter, and performing on-off control on the first converter, thereby realizing the operation control of the first converter with high control accuracy.

[0029] In some embodiments, the operating method further includes: obtaining a DC bus voltage reference value and a DC bus voltage; and performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage.

[0030] The above scheme can also be combined with the DC bus voltage and the DC bus voltage reference value to achieve voltage stabilization control of the DC bus, effectively improving the operating reliability of the new energy storage sub-module.

[0031] In some embodiments, the voltage stabilization control of the DC bus according to the DC bus voltage reference value and the DC bus voltage includes: determining a bus voltage difference according to a comparison between the DC bus voltage reference value and the DC bus voltage; performing proportional-integral adjustment according to the bus voltage difference to determine a second target duty cycle; performing pulse width modulation according to the second target duty cycle to generate a second switching signal and send it to a second converter.

[0032] The above scheme combines the bus voltage difference between the DC bus voltage reference value and the DC bus voltage, performs proportional-integral regulation and pulse width modulation in sequence, and finally generates a second switching signal to control the operation of the second converter, that is, the DC bus voltage stabilization control is realized through the second converter, which has the advantage of high voltage stabilization control accuracy.

[0033] The embodiment of the present application also provides an energy storage valve, including a submodule controller and the above-mentioned new energy storage submodule, each of the new energy storage submodules is cascaded, and each of the new energy storage submodules is respectively connected to the submodule controller.

[0034] An embodiment of the present application also provides an energy storage system, including a converter valve and the above-mentioned energy storage valve, wherein the first end and the second end formed by cascading each of the new energy storage submodules are respectively connected to the converter valve, and the converter valve is used to connect to an AC power grid.

[0035] In some embodiments, the converter valve comprises at least one of a voltage source converter valve, a grid commutated converter valve and a cascade converter valve.

[0036] An embodiment of the present application also provides an operating method based on the above-mentioned energy storage system, including: when the new energy component has output, obtaining the new energy output power of the new energy component and the system demand power of the AC power grid; according to the new energy output power and the system demand power, controlling the new energy component to output electric energy.

[0037] The above-mentioned operation method combines the new energy output power of the new energy components and the system demand power of the AC power grid to realize the output power control of the new energy components, smooth the power grid output, realize the high integration of new energy power generation and energy storage, and improve the grid-connected operation reliability of the energy storage system.

[0038] In some embodiments, controlling the new energy component to output electric energy according to the new energy output power and the system required power includes: when the new energy output power is greater than the system required power, controlling the new energy component to output electric energy to the AC power grid and the energy storage module; when the new energy output power is equal to the system required power, controlling the new energy component to output electric energy to the AC power grid; when the new energy output power is less than the system required power, controlling the new energy component and the energy storage module to output electric energy to the AC power grid at the same time.

[0039] The above scheme controls the transmission of new energy components and the charging and discharging of energy storage modules according to the relationship between the output power of new energy and the power required by the system, effectively improving the operating efficiency of the energy storage system.

[0040] In some embodiments, the operating method further includes: when the new energy component has no output, controlling the energy storage module to output electric energy to the AC power grid.

[0041] In the above scheme, when there is no output from the new energy component, the energy storage module is used to supply power to the AC grid to meet the load demand of the AC grid and improve the functional reliability of the energy storage system for the AC grid.

[0042] In some embodiments, the operating method further includes: when the new energy storage submodule is bypassed, disconnecting the power transmission between the new energy component and the energy storage module.

[0043] The above scheme interrupts the transmission of electric energy from the new energy component to the energy storage module when the new energy storage submodule is bypassed, thereby improving the operational safety of the energy storage module.

[0044] In some embodiments, the operating method also includes: when the energy storage module is fully charged, disconnecting the power transmission between the new energy component and the energy storage module; when the energy storage module is discharged to reach a preset power threshold, turning on the power transmission between the new energy component and the energy storage module.

[0045] The above scheme interrupts the transmission of electric energy from the new energy component to the energy storage module when the energy storage module is fully charged, thereby preventing the energy storage module from being overcharged and improving the charging safety of the energy storage module. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0047] Figure 1 This is a schematic diagram of application scenarios of new energy storage submodules in some embodiments of the present application;

[0048] Figure 2 This is a schematic diagram of the structure of the converter valve in some embodiments of the present application;

[0049] Figure 3 Schematic diagram of the converter valve structure in some other embodiments of the present application;

[0050] Figure 4 This is a schematic diagram of the structure of the new energy storage submodule in some embodiments of the present application;

[0051] Figure 5 This is a schematic diagram of the structure of the new energy storage submodule in some other embodiments of the present application;

[0052] Figure 6 This is a schematic diagram of the structure of the new energy storage submodule in some other embodiments of the present application;

[0053] Figure 7 This is a schematic diagram of the structure of the new energy storage submodule in some embodiments of the present application;

[0054] Figure 8 This is a schematic diagram of the structure of the new energy storage submodule in some other embodiments of the present application;

[0055] Fig. 9 This is a schematic diagram of the structure of the new energy storage submodule in some embodiments of the present application;

[0056] Fig.10 This is a schematic diagram of the operation method of the new energy storage submodule in some embodiments of the present application;

[0057] Fig.11 This is a schematic diagram of a first converter control process in some embodiments of the present application;

[0058] Fig.12 A schematic flow chart of the operation method of the new energy storage submodule in other embodiments of the present application;

[0059] Fig.13 This is a schematic diagram of the control flow of the second converter in some embodiments of the present application;

[0060] Fig.14 A schematic flow chart of an operating method of an energy storage system in some embodiments of the present invention is provided. DETAILED DESCRIPTION

[0061] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0063] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0064] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0065] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0066] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0067] At present, from the perspective of market development, new energy is gradually replacing traditional fossil energy and occupying an important position in the energy supply field. Among various types of new energy, new energy power generation has been widely used due to its stable and reliable operation, simple operation and maintenance, low maintenance cost, and long service life. New energy power generation is generally combined with AC power grid and energy storage system for grid connection operation. After the new energy components convert light energy into DC power, they can be directly transmitted to the energy storage system for storage, or they can be transmitted to the AC power grid through conversion and boosting of new energy inverters and transformers. The voltage level of new energy inverters is generally below 1KV (kilovolts). With the application of multi-level technology in new energy grid-connected systems, the voltage level of new energy inverters can even reach 35KV.

[0068] However, in the new energy grid-connected system where new energy components and energy storage systems are connected to the grid, it is inevitable that there will be abandoned light and unstable power quality due to the failure of new energy components. In particular, in the scenario where some new energy components are connected in series and / or in parallel to form a new energy array, the failure of a single new energy component will affect the operation of the entire new energy array, and in severe cases, it will even cause the new energy grid-connected system to shut down. The new energy grid-connected system has the defect of low system availability.

[0069] In order to alleviate the problem of low system availability of new energy grid-connected systems, research has found that centralized new energy components can be distributed in energy storage systems. Through the distributed setting of new energy components, the impact of single new energy component failures on the new energy grid-connected system can be reduced, thereby improving the system availability of the new energy grid-connected system.

[0070] Based on the above considerations, in order to realize the distributed setting of new energy components, a new energy storage submodule integrated with new energy components was designed through in-depth research. Specifically, a new energy storage submodule including a DC bus, a power module, an energy storage module, a converter and new energy components is built, and the new energy components are connected to the energy storage system in the form of a new energy storage submodule to realize the grid-connected operation of new energy power generation and energy storage system.

[0071] Through the above method, the new energy components are distributedly arranged in each new energy storage sub-module, and the new energy components are modularized with good flexibility, which can reduce the impact of single failure of new energy components on the new energy grid-connected system. That is, when a single new energy component fails, the new energy storage sub-module where the failed new energy component is located can be removed, which will not have a significant impact on the operation of other new energy components, and increase the proportion of the operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0072] The new energy storage submodule provided in the embodiment of the present application is applied to the energy storage system. After the energy storage system is connected to the AC power grid, a new energy grid-connected system can be constructed. Specifically, the energy storage system can be a DC direct-connected type energy storage system, which can be combined with reference to Figure 1 In this energy storage system, each new energy storage sub-module 11 is cascaded in sequence, and the structure formed after the cascading is connected to the sub-module controller to form an energy storage valve 10. The energy storage valve 10 is connected to the converter valve 20, and the converter valve 20 is further connected to the AC power grid 30, finally obtaining a new energy grid-connected system.

[0073] It should be noted that the type of the converter valve 20 in the above energy storage system is not limited. Any device that can realize the rectification and inversion functions can be used. The type can be set according to actual needs. For example, in one embodiment, the converter valve 20 includes a line commutated converter (LCC) converter valve, a VSC (voltage sourced converter) converter valve, etc. Furthermore, the VSC converter valve can also be two single-level converters, a three-level converter, or Figure 2 The modular multilevel converter (MMC) converter valve shown in the figure is not specifically limited. In another embodiment, the converter valve 20 can also be Figure 3 The cascade converter valve shown can be set according to actual needs.

[0074] See also Figure 4 An embodiment of the present application provides a new energy storage sub-module, including a DC bus 411, a power module 413, an energy storage module 415, a first converter 417 and a new energy component 419, the energy storage module 415 is connected to the power module 413 through the DC bus 411, the first converter 417 is connected to the DC bus 411, and the new energy component 419 is connected to the first converter 417.

[0075] Specifically, the DC bus 411 is a line for transmitting DC power between the energy storage module 415 and the power module 413. The power module 413 is a device for realizing power conversion; the energy storage module 415 is a device for storing electric energy and releasing electric energy when there is a need for discharge. The new energy component 419 is a device that can generate electric energy through new energy generation. The first converter 417 is a device that can convert the electric energy generated by the new energy component 419 into a DC power of a suitable size and transmit it to the DC bus.

[0076] It should be noted that the specific type of the new energy component 419 is not unique, and can be one or more of a photovoltaic component, a wind power generation component, a biomass power generation component, and a tidal power generation component. Correspondingly, the type of the first converter 417 will also be different. If the electric energy generated by the new energy component 419 is alternating current, the corresponding first converter 417 should use an alternating current / direct current converter (i.e., an AC / DC converter). If the electric energy generated by the new energy component 419 is direct current, the corresponding first converter 417 should use a direct current converter (i.e., a DC-DC converter).

[0077] In order to facilitate understanding of the technical solution of the present application, the following embodiments are explained by taking the new energy component 419 as a photovoltaic component to achieve photoelectric conversion, and the first converter 417 as a DC converter as an example. In this way, the power generation operation stability of the new energy storage submodule can be effectively improved.

[0078] During the normal operation of the new energy component 419, the light energy is converted into electrical energy, which is transmitted in the form of DC electrical energy. After the first converter 417 performs DC conversion, it is converted into DC electrical energy suitable for the energy storage module 415 and then transmitted to the energy storage module 415 for storage. The new energy component 419 can also be connected to a new energy inverter outside the new energy storage submodule, and the DC electrical energy generated by the new energy component 419 is transmitted to the new energy inverter for conversion to obtain AC electrical energy, which is then boosted by the subsequent transformer and then transmitted to the AC power grid for use.

[0079] In actual usage scenarios, the new energy storage submodule only needs to choose to transmit DC power to the energy storage module 415 and / or the AC power grid based on the system power demand of the AC power grid and the amount of electricity stored in the energy storage module 415, so as to minimize the occurrence of abandoned light from the new energy component 419.

[0080] It should be noted that the specific type of power module 413 is not unique, and it can be a full-bridge power module or a half-bridge power module, which can be selected in combination with actual needs. In a more detailed embodiment, a half-bridge power module is used as an example for explanation, see Figure 5The power module 413 includes a half-bridge power unit 510 and a parallel DC support capacitor C. Further, in one embodiment, please continue to refer to Figure 5 The power module 413 further includes a voltage balancing resistor R arranged in parallel with the DC support capacitor C, and / or further includes a bypass switch P arranged on a side of the half-bridge power unit away from the DC support capacitor C.

[0081] Similarly, the specific structure of the energy storage module 415 is not unique. In one embodiment, please refer to Figure 5 The energy storage module 415 includes an energy storage battery pack S and a charge and discharge circuit. One end of the energy storage battery pack S is connected to the DC bus 411 through the charge and discharge circuit, and the other end of the energy storage battery pack S is connected to the DC bus 411. The specific structure of the charge and discharge circuit is not unique. Figure 5 As shown, it may include a pre-charge resistor R1, a pre-charge switch K1 and a normal switch K2. The pre-charge resistor R1 and the pre-charge switch K1 are connected in series and then connected in parallel to both ends of the normal switch K2, thereby forming a charge and discharge circuit. The energy storage battery pack S may include multiple lithium batteries, each of which is connected in series and / or in parallel to form an energy storage battery pack S.

[0082] In a more detailed embodiment, please refer to Figure 5 The new energy storage submodule also includes an isolating switch K. The energy storage module 415 is connected to the power module 413 through the isolating switch K. By opening the isolating switch K, electrical isolation between the energy storage module 415 and the power module 413 is achieved, thereby improving the operating safety of the new energy storage submodule.

[0083] In the above scheme, in the new energy grid-connected system, the new energy component 419 is distributedly arranged in each sub-module, and a new energy storage sub-module including a DC bus 411, a power module 413, an energy storage module 415, a first converter 417 and a new energy component 419 is constructed, and the new energy component 419 is connected to the energy storage system in the form of a new energy storage sub-module for operation. Through this scheme, the new energy component 419 is distributedly arranged in each new energy storage sub-module, and the new energy component 419 is modularized, which has good flexibility and can reduce the impact of a single failure of the new energy component 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be removed, which will not have a significant impact on the operation of other new energy components 419, and the operating time proportion of the new energy grid-connected system is increased, thereby effectively improving the system availability of the new energy grid-connected system.

[0084] See also Figure 6In some embodiments, the new energy storage submodule further includes a second converter 612, which is disposed between the DC bus 411 and the energy storage module 415 and is connected to the DC bus 411 and the energy storage module 415 respectively.

[0085] Specifically, the second converter 612 is a converter that can transmit DC power bidirectionally. Specifically in the embodiment of the present application, bidirectional transmission refers to the DC power output by the new energy component 419, which can be input into the energy storage module 415 through the second converter 612 to realize charging of the energy storage module 415; and can also output the electric energy stored in the energy storage module 415 through the second converter 612 to realize discharging of the energy storage module 415.

[0086] Moreover, through the setting of the second converter 612 in the embodiment of the present application, during the operation of the new energy storage sub-module, the operation of the switching device in the second converter 612 can be controlled in combination with the change of the DC bus voltage, so as to achieve the purpose of stabilizing the DC bus 411 and effectively improve the operating stability of the new energy storage sub-module.

[0087] In the above solution, a second converter 612 is further provided between the power module 413 and the energy storage module 415 . The energy storage module 415 can realize DC voltage conversion during charging and discharging through the second converter 612 to meet the charging and discharging requirements of the energy storage module 415 .

[0088] The specific type of the second converter 612 is not limited. In some embodiments, the second converter 612 includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

[0089] Specifically, an isolated DC converter refers to a device that achieves DC voltage to DC voltage conversion through isolation elements. The isolation elements can reduce the possibility of circuit coupling between the input and output ends, and improve operational safety and stability. Isolation elements generally include transformers and optocouplers. A non-isolated DC converter is a device that directly connects to the circuit and performs DC to DC voltage conversion without using isolation elements such as transformers. A bidirectional isolated DC converter refers to an isolated DC converter that can transmit DC voltage in both directions; a bidirectional non-isolated DC converter refers to a non-isolated DC converter that can transmit DC voltage in both directions.

[0090] Depending on the actual usage scenario or requirements, in the new energy storage sub-module, the second converter 612 can be set to an isolated DC converter, that is, a bidirectional isolated DC converter; or it can be set to a non-isolated DC converter, that is, a bidirectional non-isolated DC converter, without specific limitation.

[0091] In the above solution, the second converter 612 can be configured as a bidirectional non-isolated DC converter or a bidirectional isolated DC converter, which can be selected based on the actual scenario, and has high configuration flexibility.

[0092] See also Figure 7 In some embodiments, the DC bus 411 includes a first-end DC bus and a second-end DC bus, the bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1, the first end of the first inductor L1 is connected to the first end of the first switching device Q1 and the first-end DC bus, the second end of the first inductor L1 is connected to the energy storage module 415, the second end of the first switching device Q1 is connected to the second-end DC bus and the energy storage module 415, and the third end of the first switching device Q1 is used to receive a switching signal sent by the sub-module controller.

[0093] Specifically, the first-end DC bus is the positive-end DC bus or the negative-end DC bus, and the second-end DC bus can also be the positive-end DC bus or the negative-end DC bus, as long as the polarity is opposite to that of the first-end DC bus. In the case where the DC bus 411 includes the first-end DC bus and the second-end DC bus, the two ends of the first-end DC bus are respectively connected to the power module 413 and the bidirectional non-isolated DC converter, and the two ends of the second-end DC bus are also respectively connected to the power module 413 and the bidirectional non-isolated DC converter, and the first converter 417 is respectively connected to the first-end DC bus and the second-end DC bus between the power module 413 and the second converter 612.

[0094] The solution of this embodiment is explained by taking a bidirectional non-isolated DC converter as an example. The bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1, which are constructed to form a boost converter, and the boost converter is used as the bidirectional non-isolated DC converter.

[0095] Based on the new energy storage submodule of this embodiment, in the actual operation process, the submodule controller corresponding to the new energy storage submodule will perform voltage stabilization control of the DC bus 411, which can be a submodule controller corresponding to a new energy storage submodule, or a submodule controller corresponding to multiple new energy storage submodules, or a submodule controller corresponding to all new energy storage submodules. In the process of voltage stabilization control of the DC bus 411, the submodule controller can obtain the DC bus voltage and the output voltage required by the current new energy storage submodule (which can be used as a DC bus voltage reference value), and complete the DC bus 411 voltage stabilization control with the DC bus voltage reference value and the DC bus voltage.

[0096] It can be understood that there is not only one way to obtain the DC bus voltage. In one embodiment, a voltage detector may be provided at a corresponding position of the DC bus 411, and the DC bus voltage may be collected by the voltage detector. In another embodiment, the voltage collection function may be integrated in the submodule controller, and the submodule controller may be connected to the corresponding position of the DC bus 411 through a strong current-weak current conversion board to realize DC bus voltage collection.

[0097] It should be noted that the way in which the third terminal of the first switch device Q1 receives the switch signal sent by the sub-module controller is not unique. In a more detailed embodiment, the third terminal of the first switch device Q1 may be connected to a strong current-weak current conversion board, and then connected to the sub-module controller through the strong current-weak current conversion board, thereby realizing the reception of the switch signal. In another embodiment, the sub-module controller may also have strong current operation conditions, and in this case, the sub-module controller is directly connected to the third terminal of the first switch device Q1.

[0098] In the above solution, the second converter 612 specifically adopts a bidirectional non-isolated DC converter, and the bidirectional non-isolated DC converter includes a first inductor L1 and a first switch device Q1, which has a simple structure and is easy to implement, and has the advantage of high economic efficiency.

[0099] In some embodiments, the new energy storage submodule further includes an insulating support assembly, and the new energy assembly 419 is disposed on the insulating support assembly.

[0100] Specifically, the insulating support component is a support device made of insulating material and having an insulating function. In the solution of this embodiment, the new energy storage submodule includes an insulating support component, and the new energy component 419 is set on the insulating support component, and then the insulating support component is further placed on a setting platform (such as the ground) to achieve high-voltage insulation between the new energy component 419 and the ground, thereby improving the operating safety of the new energy storage submodule.

[0101] In a more detailed embodiment, in the new energy storage sub-module, the power module 413, the energy storage module 415 and the new energy component 419 are all arranged on an insulating support component, which is set up on a placement platform through the insulating support component to improve the operating safety of the new energy storage sub-module.

[0102] It can be understood that the power module 413, the energy storage module 415 and the new energy component 419 can be distributedly installed with different insulating support components, or can be installed simultaneously in one insulating support component, without specific limitation.

[0103] It should be noted that the specific type of the insulating support assembly is not limited, and any device having an insulating support function can be used. For example, in a more detailed embodiment, the insulating support assembly includes a support insulator.

[0104] In the above solution, the new energy component 419 is arranged on the insulating support component, and voltage isolation is performed through the insulating support component to improve the operating reliability of the new energy component 419.

[0105] In some embodiments, the first converter 417 includes a non-isolated DC converter.

[0106] Specifically, the scheme of this embodiment is explained by taking the output of DC power by the new energy component 419 as an example. Corresponding to the above-mentioned new energy component 419 being arranged on the insulating support component, the high-voltage isolation problem of the new energy component 419 can be solved by the arrangement of the insulating support component. Therefore, when the new energy component 419 is connected to the DC bus 411, there is no need to perform electrical isolation again. Through the scheme of this embodiment, in the new energy grid-connected system, the grid-connection of the new energy component 419 does not require a high-voltage isolation converter, and can be achieved through a non-isolated converter, that is, the new energy component 419 is connected to the DC bus 411 through a non-isolated DC converter.

[0107] In the above solution, when the new energy component 419 is voltage-isolated by the insulating support component, the first converter 417 between the new energy component 419 and the DC bus 411 directly adopts a non-isolated first converter 417, which can effectively reduce costs.

[0108] It can be understood that in other embodiments, when the new energy component 419 is arranged in an insulating support component, in order to further improve the high-voltage isolation reliability of the new energy component 419, the first converter 417 can also be set as an isolated DC converter, which can be selected based on actual needs.

[0109] Please refer to Figure 8 In some embodiments, the DC bus 411 includes a first-end DC bus and a second-end DC bus, the non-isolated DC converter includes a first capacitor C1, a second inductor L2, and a second switch device Q2, the first end of the first capacitor C1 is connected to the new energy component 419 and the first end of the second inductor L2, the second end of the second inductor L2 is connected to the first end of the second switch device Q2 and the first-end DC bus, the second end of the first capacitor C1 is connected to the new energy component 419 and the second end of the second switch device Q2, the second end of the second switch device Q2 is also connected to the second-end DC bus, and the third end of the second switch device Q2 is used to receive a switching signal sent by the sub-module controller.

[0110] Specifically, in the solution of this embodiment, the non-isolated DC converter includes a first capacitor C1, a second inductor L2 and a second switching device Q2, that is, a boost-type converter is constructed by the first capacitor C1, the second inductor L2 and the second switching device Q2, so as to realize the DC voltage conversion and output of the new energy component 419 to the energy storage module 415.

[0111] Based on the non-isolated DC converter of the embodiment of the present application, the submodule controller corresponding to the new energy storage submodule can realize the maximum power point tracking (MPPT, Maximum Power Point Tracking) control. Specifically, an MPPT controller is provided in the submodule controller. During the operation of the new energy component 419, the output current and output voltage of the new energy component 419 are obtained through the MPPT controller, and the maximum power point tracking is performed according to the output current and output voltage to obtain the voltage parameters required by the new energy component 419 when the maximum power point is running, that is, the target output voltage. After that, the submodule controller uses the target output voltage as a reference value, and regulates it in combination with the output voltage of the new energy component 419, and controls the operation of the first converter 417 with the regulation result, specifically, controls the on and off of the second switching device Q2 in the first converter 417 to complete the maximum power point tracking.

[0112] It can be understood that in one embodiment, the new energy storage submodule can only be provided with the first converter 417, and the first converter 417 includes a first capacitor C1, a second inductor L2 and a second switch device Q2. At this time, the submodule controller only needs to implement maximum power tracking control according to the output voltage and output current of the new energy component 419. In this embodiment, due to the voltage clamping effect of the energy storage battery group S in the energy storage module 415, the voltage of the DC bus 411 will not change suddenly, and the voltage of the DC bus 411 can be clamped by the energy storage battery group S to achieve voltage stabilization of the DC bus 411.

[0113] In another embodiment, the new energy storage submodule can be provided with a first converter 417 and a second converter 612 at the same time, the first converter 417 includes a first capacitor C1, a second inductor L2 and a second switch device Q2, and the second converter 612 includes a first inductor L1 and a first switch device Q1. In the scheme of this embodiment, the submodule controller can not only realize the maximum power point tracking control according to the output voltage and output current of the new energy component 419, but also realize the voltage stabilization control of the DC bus 411 in combination with the DC bus voltage and the DC bus voltage reference value (which can be combined with the output voltage of the new energy storage submodule required to meet the system requirements when the new energy storage submodule is actually put into operation in the energy storage system).

[0114] In the above scheme, the non-isolated DC converter is constructed by the first capacitor C1, the second inductor L2 and the second switch device Q2, that is, the boost converter is used to convert the DC voltage between the new energy component 419 and the energy storage module 415, which has the advantage of high stability of the output voltage.

[0115] In some embodiments, the first converter 417 includes an isolated DC converter.

[0116] Specifically, unlike the above-mentioned new energy component 419 being arranged in the insulating support component and the first converter 417 being arranged as a non-isolated DC converter, in the solution of this embodiment, the high voltage isolation problem of the new energy component 419 is solved by arranging an isolated DC converter. Accordingly, under the solution of this embodiment, the new energy component 419 does not need to be arranged in the insulating support component, and the safe operation of the new energy storage submodule can be ensured.

[0117] In the above scheme, the first converter 417 between the new energy component 419 and the DC bus 411 adopts an isolated DC converter. The high-voltage isolation of the new energy component 419 can be achieved through the isolated converter, so that the new energy component 419 can be erected without an insulating support component, thereby improving the construction convenience of the new energy storage sub-module.

[0118] See also Fig. 9 In some embodiments, the new energy storage submodule further includes a third converter 912, which is disposed between the DC bus 411 and the power module 413 and connected to the DC bus 411 and the power module 413 respectively.

[0119] Specifically, the energy storage module 415 is connected to the third converter 912 via the DC bus 411, and the first converter 417 is connected to the DC bus, so that the first converter 417 is connected between the energy storage module 415 and the third converter 912, and the DC power converted by the first converter 417 can be directly transmitted to the energy storage module 415 for storage.

[0120] In the above scheme, the energy storage module 415 is connected to the third converter 912 via the DC bus 411, so that the new energy component 419 is directly connected between the third converter 912 and the energy storage module 415. The electric energy generated by the new energy component 419 can be transmitted to the energy storage module 415 without passing through the third converter 912, which can effectively improve the efficiency of electric energy transmission.

[0121] The embodiment of the present application also provides an operating method based on the above-mentioned new energy energy storage sub-module, including: when the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; when the electric energy supply conditions are met, the electric energy output by the new energy component is converted by the first converter and the power module and then transmitted to the power grid for load power supply.

[0122] Specifically, the structure of the new energy storage submodule is as shown in the above-mentioned embodiments and the accompanying drawings, and will not be repeated here. Meeting the electric energy storage condition means that the new energy storage submodule has the need to store the electric energy generated by the new energy component 419 through the energy storage module 415. The specific form of meeting the electric energy storage condition is not unique. In one embodiment, it may be that when the energy storage module 415 is not fully charged with electric energy, it is considered that the electric energy storage condition is met. In other embodiments, it may also be that the energy storage system is not connected to the power grid, or the load in the power grid cannot completely consume the electric energy generated by the new energy component 419, it is considered that the electric energy storage condition is met. In other embodiments, it may also be that when the new energy storage submodule receives an energy storage scheduling instruction manually sent by the user, it is considered that the electric energy storage condition is met.

[0123] Meeting the power supply condition means that the new energy storage submodule has a need to supply power to the external load through the power module 413. The specific form is also not unique. In one embodiment, it may be that the load in the power grid has a power demand. In other embodiments, it may also be that the new energy storage submodule receives a power supply scheduling instruction manually sent by the user and considers that the power supply condition is met.

[0124] It can be understood that the electric energy output by the new energy component 419 can be transmitted to the energy storage module 415 for storage, and at the same time, transmitted to the power grid for power supply through the first converter and the power module 413. That is, the electric energy storage and the electric energy supply can be realized at the same time or separately, and there is no specific limitation.

[0125] In the solution of this embodiment, the new energy storage submodule can transmit the electric energy generated by the new energy component 419 to the energy storage module 415 for storage, or transmit it to the power grid for load power supply according to manual scheduling by the user, etc., and the specific selection can be based on actual needs.

[0126] In the above scheme, the electric energy generated by the new energy component 419 can be transmitted to the energy storage module 415 for storage according to actual conditions, and / or transmitted to the power grid to power the load, thereby reducing the waste of the electric energy generated by the new energy component 419 and improving the electric energy utilization rate of the new energy component 419.

[0127] See also Fig.10 In some embodiments, the operating method further includes step 902, step 904 and step 906.

[0128] Step 902, obtaining the output electrical parameters of the new energy component.

[0129] Step 904 , determining the target output voltage of the new energy component when operating at maximum power according to the output electrical parameters.

[0130] Step 906: Control the operation of the first converter according to the output electrical parameter and the target output voltage.

[0131] Specifically, the new energy storage submodule is as shown in the above embodiment and the accompanying drawings. In the scheme of this embodiment, the new energy storage submodule also includes a controller, and the controller is connected to the first converter. The controller can be a device independently set relative to the submodule controller, and the submodule controller can be directly used as the controller, and the specific details are not repeated. For ease of understanding, the controller is explained below as the submodule controller. In the scheme of the embodiment of the present application, the new energy storage submodule is connected to the submodule controller in communication. When the new energy component 419 transmits DC power to the energy storage module 415, the submodule controller can obtain the output electrical parameters of the new energy component 419 output to the first converter 417, and then analyze based on the obtained output electrical parameters to obtain the target output voltage when the new energy component 419 in the current new energy storage submodule is running at the maximum output power. Finally, the submodule controller performs feedback adjustment with the target output voltage and output electrical parameters, so that the photovoltaic panel finally works in the state of maximum power operation, realizing the maximum power operation control of the new energy component 419.

[0132] The above solution can be combined with the output electrical parameters of the new energy component 419 to maintain the new energy component 419 running at maximum power and improve the operating efficiency of the new energy component 419.

[0133] It should be noted that the specific type of output electrical parameters is not unique. In a more detailed embodiment, the output electrical parameters include output voltage and output current, that is, the output voltage and output current of the new energy component 419. Accordingly, in some embodiments, step 904 includes: performing maximum power point tracking control according to the output voltage and output current to determine the target output voltage when the new energy component operates at maximum power; step 906 includes: controlling the operation of the first converter according to the output voltage and the target output voltage.

[0134] Specifically, the solution of this embodiment determines the target output voltage of the new energy component 419 when it is running at the maximum output power through the output voltage and output current of the new energy component 419. Specifically, the maximum power point tracking is performed according to the MPPT controller in the submodule controller, and the target output voltage that can achieve the maximum power output of the new energy component 419 at this time is found in combination with the MPPT algorithm, and is used as the reference voltage. The submodule controller then regulates the obtained reference voltage and output voltage to obtain the regulation parameters required to make the output voltage of the new energy component 419 track the target output voltage, and controls the operation of the first converter 417 with the obtained regulation parameters.

[0135] It should be noted that the submodule controller is not the only way to obtain the output current and output voltage. In one embodiment, a voltage collector and a current collector may be provided at the output end of the new energy component 419, and the output voltage and output current may be collected by the voltage collector and the current collector respectively, and transmitted to the submodule controller. The specific transmission method is not unique, and the voltage collector and the current collector may be connected to a strong current-weak current conversion board, and then the submodule controller obtains the voltage and current through the strong current-weak current conversion board.

[0136] The above scheme can be combined with the output current and output voltage of the new energy component 419 to perform maximum power point tracking control, thereby maintaining the new energy component 419 operating at the maximum power point and improving the operating efficiency of the new energy component 419.

[0137] See also Fig.11 In some embodiments, the operation of the first converter is controlled according to the output voltage and the target output voltage: including step 1002, step 1004 and step 1006.

[0138] Step 1002: Determine the output voltage difference by comparing the output voltage with the target output voltage.

[0139] Step 1004: Perform proportional-integral regulation according to the output voltage difference to determine a first target duty cycle.

[0140] Step 1006 , performing pulse width modulation according to the first target duty cycle, generating a first switching signal and sending it to the first converter.

[0141] Specifically, please refer to Figure 7 or Figure 8, the first converter 417 includes a first capacitor C1, a second inductor L2 and a second switch device Q2, and the submodule controller includes an MPPT controller, a comparator, a proportional integral (PI, ProportionalIntegral) regulator and a pulse width modulation (PWM, Pulse Width Modulation) signal generator. The MPPT controller of the submodule controller is connected to the output end of the new energy component 419 to obtain the output current I_PV of the new energy component 419, and the MPPT controller is connected to the first capacitor C1 set in parallel with the new energy component 419, and the voltage of the first capacitor C1 is used as the output voltage U_PV of the new energy component 419. After the MPPT controller performs maximum power point tracking to obtain the target output voltage, the target output voltage and the output voltage are compared in the comparator to obtain the output voltage difference U_ref. After that, the output voltage difference is transmitted to the PI regulator for PI regulation, and the first target duty cycle is output. Finally, the PWM signal generator generates a corresponding first switching signal in combination with the first target duty cycle, and sends it to the second switching device Q2, and the switching signal is used to control the on and off of the second switching device Q2 to complete the maximum power tracking control.

[0142] The above scheme combines the output voltage and the target output voltage to perform proportional-integral regulation, and performs pulse width modulation on the result of the proportional-integral regulation, thereby determining the first switching signal required for the operation of the first converter 417, and performing on-off control on the first converter 417, thereby realizing the operation control of the first converter 417 with high control accuracy.

[0143] See also Fig.12 In some embodiments, the operating method further includes step 112 and step 114.

[0144] Step 112, obtaining a DC bus voltage reference value and a DC bus voltage.

[0145] Step 114, performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage.

[0146] Specifically, the DC bus voltage reference value refers to the output voltage required by a single new energy storage submodule calculated in combination with actual power demand when the new energy storage submodule is connected to the energy storage system and the energy storage system is operated with a fixed number of new energy storage submodules. The new energy storage submodule is connected to the submodule controller in communication (a strong current-weak current conversion board can be set between the two). During the charging and discharging process of the energy storage module 415, the submodule controller can obtain the DC bus voltage reference value and the DC bus voltage, and perform voltage stabilization control to maintain the DC bus voltage stable.

[0147] Similarly, there is not only one way to obtain the DC bus voltage. A voltage detector may be set at the corresponding position of the DC bus 411 to collect the DC bus voltage; or the voltage collection function may be integrated in the sub-module controller, and the sub-module controller is connected to the high-current-low-current conversion board, and then connected to the corresponding position of the DC bus 411 through the high-current-low-current conversion board to realize DC bus voltage collection, without specific limitation.

[0148] The above scheme can also be combined with the DC bus voltage and the DC bus voltage reference value to achieve voltage stabilization control of the DC bus 411, effectively improving the operating reliability of the new energy storage sub-module.

[0149] See also Fig.13 In some embodiments, step 114 includes step 122 , step 124 , and step 126 .

[0150] Step 122: Determine the bus voltage difference by comparing the DC bus voltage reference value with the DC bus voltage.

[0151] Step 124, performing proportional-integral regulation according to the bus voltage difference to determine a second target duty cycle.

[0152] Step 126 , performing pulse width modulation according to the second target duty cycle, generating a second switching signal and sending it to the second converter.

[0153] Specifically, please refer to Figure 7 In the embodiment of the present application, the second converter 612 includes a first inductor L1 and a first switching device Q1, and the submodule controller includes a comparator, a PI regulator and a PWM signal generator. The submodule controller obtains the voltage across the DC support capacitor C in the power module 413, and uses it as the DC bus voltage. The DC bus voltage and the DC bus voltage reference value are compared in the comparator to obtain the bus voltage difference. The bus voltage difference is then transmitted to the PI regulator for PI regulation, and the second target duty cycle is output. Finally, the PWM signal generator generates a corresponding second switching signal in combination with the second target duty cycle, and sends it to the first switching device Q1, and uses the switching signal to control the on and off of the first switching device Q1 to complete the DC bus 411 voltage regulation control.

[0154] The above scheme combines the bus voltage difference between the DC bus voltage reference value and the DC bus voltage, performs proportional-integral regulation and pulse width modulation in sequence, and finally generates a second switching signal to control the operation of the second converter 612, that is, the DC bus 411 is controlled by the second converter 612, which has the advantage of high voltage control accuracy.

[0155] The embodiment of the present application also provides an energy storage valve, including a submodule controller and the above-mentioned new energy storage submodule, the new energy storage submodule is communicatively connected with the submodule controller, and each new energy storage submodule is cascaded.

[0156] Specifically, the submodule controller is used to execute the steps of any of the above-mentioned operating methods, the specific structure of the new energy storage submodule and the implementation of the operating mode, as shown in the above-mentioned embodiments and drawings, will not be repeated here. In actual scenarios, each new energy storage submodule of the energy storage valve is connected to a corresponding submodule controller, that is, each submodule controller independently controls the operation of the new energy storage submodule connected to it in communication. In another embodiment, a submodule controller can also be selected according to actual needs to control the operation of two or more new energy storage submodules at the same time, without specific limitation.

[0157] In the energy storage valve of the embodiment of the present application, in each cascaded new energy storage sub-module, the new energy component 419 is distributedly arranged in each new energy storage sub-module, and the new energy component 419 is modularized, which has good flexibility and can reduce the impact of a single failure of the new energy component 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be cut off, which will not have a significant impact on the operation of other new energy components 419, thereby increasing the proportion of the operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0158] An embodiment of the present application also provides an energy storage system, including a converter valve and the above-mentioned energy storage valve, wherein the first end and the second end formed by cascading each new energy storage submodule are respectively connected to the converter valve, and the converter valve is used to connect to an AC power grid.

[0159] Specifically, the cascaded new energy storage submodules in the energy storage valve are as shown in the above embodiments and drawings, and will not be described in detail here. In the solution of the embodiment of the present application, the converter valve can be a converter valve including at least one of a voltage source converter valve, a grid commutation converter valve and a cascade converter valve.

[0160] The type of converter valve is not limited to one, and any device that can realize the rectification and inversion functions can be used, and it can be set according to actual needs. For example, in one embodiment, the converter valve includes a grid commutation converter valve or a VSC converter valve. Furthermore, the VSC converter valve can also be two single-level converters, a three-level converter, or Figure 2 The modular multilevel converter valve shown is not specifically limited. In another embodiment, the converter valve may also be Figure 3 The cascade converter valve shown can be set according to actual needs.

[0161] Through this solution, the new energy components 419 are distributedly arranged in various new energy energy storage sub-modules, and the new energy components 419 are modularized, which has good flexibility and can reduce the impact of single-unit failures of new energy components 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be removed, which will not have a significant impact on the operation of other new energy components 419, thereby increasing the proportion of operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0162] See also Fig.14 , an embodiment of the present application also provides an operating method based on the above energy storage system, including step 132 and step 134.

[0163] Step 132, when the new energy component has output, obtain the new energy output power of the new energy component and the system required power of the AC power grid.

[0164] Step 134, controlling the new energy component to output electric energy according to the new energy output power and the system required power.

[0165] Specifically, the structure of the energy storage system is as shown in the above embodiments and the accompanying drawings, and the new energy output power is the sum of the output powers of the new energy components 419 in each new energy storage submodule with new energy output. The system demand power is the sum of the demand powers of each power-consuming device in the AC power grid, which is obtained by statistical analysis of the AC power grid and transmitted to the system controller.

[0166] In the scheme of this embodiment, the energy storage system includes the above-mentioned energy storage valve, the converter valve and the control device, and the energy storage valve and the converter valve are respectively connected to the control device. During the operation of the energy storage system, the control device obtains the output power of the new energy and the power required by the system, and combines the size relationship between the two to realize the power supply of the AC power grid. It should be pointed out that the overall logic of the operation control of the energy storage system should follow the principle of giving priority to satisfying the AC power grid, that is, when the output power of the new energy is in excess, the excess electric energy is transmitted to the energy storage module 415 for storage.

[0167] The operating method of the above energy storage system combines the new energy output power of the new energy component 419 and the system demand power of the AC power grid to realize the output power control of the new energy component 419, smooth the power grid output, realize the high integration of new energy power generation and energy storage, and improve the grid-connected operation reliability of the energy storage system.

[0168] In some embodiments, step 134 includes: when the output power of the new energy is greater than the system required power, controlling the new energy component 419 to output electric energy to the AC power grid and the energy storage module 415; when the output power of the new energy is equal to the system required power, controlling the new energy component 419 to output electric energy to the AC power grid; when the output power of the new energy is less than the system required power, controlling the new energy component 419 and the energy storage module 415 to output electric energy to the AC power grid at the same time.

[0169] Specifically, in the solution of this embodiment, if the output power of the new energy is greater than the power required by the system, after the output power of the new energy component 419 meets the needs of the AC power grid, the remaining output power will be supplied to the energy storage module 415 to charge the energy storage module 415. In this case, the control device conducts the connection between each new energy component 419 and the AC power grid (which can be achieved by turning on the new energy inverter), and the electric energy generated by the new energy component 419 is transmitted to the AC power grid. When the needs of the AC power grid are met, the control device conducts the connection between the remaining new energy components 419 and the energy storage module 415. Specifically, if only the first converter 417 is set, it is sufficient to control the first converter 417 to be turned on. If the first converter 417 and the second converter 612 are provided at the same time, it is necessary to control both the first converter 417 and the second converter 612 to be turned on and run.

[0170] It can be understood that in a more detailed embodiment, when the new energy output power is greater than the system required power, the control device can combine the power status of the energy storage modules 415 in each new energy storage sub-module, and give priority to controlling the new energy components 419 in the same new energy storage sub-module as the energy storage module 415 with higher power, and connect them to the AC power grid for operation, and the remaining new energy components 419 charge the corresponding energy storage modules 415 with lower power, thereby further improving the operating reliability of the energy storage system.

[0171] If the output power of new energy is equal to the power required by the system, the power output by the new energy component 419 is just used by the AC system. Therefore, it is only necessary to control the new energy components 419 in each new energy storage sub-module and connect them to the AC power grid for operation. At this time, the energy storage module 415 is neither charged nor discharged.

[0172] If the new energy output power is less than the system demand power, the output power of the new energy component 419 cannot meet the demand of the AC power grid, and it is necessary to control the energy storage module 415 of some or all of the new energy storage sub-modules to provide power for the AC power grid, that is, some or all of the energy storage modules 415 discharge at this time.

[0173] The above scheme controls the power transmission of the new energy component 419 and the charging and discharging of the energy storage module 415 according to the relationship between the output power of the new energy and the power required by the system, thereby effectively improving the operating efficiency of the energy storage system.

[0174] In some embodiments, the operation method of the energy storage system further includes: when the new energy component 419 does not have output, controlling the energy storage module 415 to output electric energy to the AC power grid.

[0175] Specifically, the new energy component 419 has no output, that is, in the energy storage system, all the new energy components 419 have no power output, that is, the new energy component 419 has not performed power conversion (it may be a failure, outage or night scene of the new energy component 419). At this time, in order to meet the power demand of the AC power grid, it is necessary to control the discharge of the energy storage module 415 of some or all new energy storage submodules in combination with the system demand power.

[0176] In the above solution, when the new energy component 419 has no output, the energy storage module 415 supplies power to the AC grid to meet the load demand of the AC grid and improve the functional reliability of the energy storage system for the AC grid.

[0177] In some embodiments, the operation method of the energy storage system further includes: when the new energy storage submodule is bypassed, disconnecting the power transmission between the new energy component 419 and the energy storage module 415 .

[0178] Specifically, the new energy storage submodule bypass, that is, the new energy storage submodule is cut out of the energy storage system. In order to improve the operation safety of the new energy storage submodule, it is necessary to disconnect the power transmission between the new energy component 419 and the energy storage module 415.

[0179] It should be noted that the method of disconnecting the power transmission between the new energy component 419 and the energy storage module 415 is not unique. In one embodiment, if the new energy storage submodule includes only the first converter 417, it is sufficient to disconnect the first converter 417. In another embodiment, if the new energy storage submodule includes the first converter 417 and the second converter 612, the power transmission between the new energy component 419 and the energy storage module 415 can be interrupted by disconnecting at least one of the first converter 417 and the second converter 612.

[0180] The above solution, when the new energy storage submodule is bypassed, interrupts the transmission of electric energy from the new energy component 419 to the energy storage module 415 , thereby improving the operational safety of the energy storage module 415 .

[0181] In some embodiments, the operation method of the energy storage system also includes: when the energy storage module 415 is fully charged, disconnecting the power transmission between the new energy component 419 and the energy storage module 415; when the energy storage module 415 is discharged to reach a preset power threshold, turning on the power transmission between the new energy component 419 and the energy storage module 415.

[0182] Specifically, full charge means that the power of the energy storage battery group S in the energy storage module 415 reaches the preset full charge threshold. In the solution of this embodiment, if the new energy component 419 transmits electric energy to the energy storage module 415 to charge the energy storage module 415, the control device will obtain the power of the energy storage module 415 in real time (which can be obtained through the battery management system of the energy storage battery group S) for analysis. When the power of the energy storage battery group S reaches the preset full charge threshold, the first converter 417 is controlled to stop running and the charging of the energy storage module 415 is interrupted. After that, the control device continuously monitors the power of the energy storage module 415. If it is found that the energy storage module 415 is discharged so that the power reaches the preset power threshold, the first converter 417 can be controlled to start and charge the energy storage module 415 again.

[0183] The above solution, when the energy storage module 415 is fully charged, interrupts the new energy component 419 to transmit electric energy to the energy storage module 415 to prevent the energy storage module 415 from being overcharged, thereby improving the charging safety of the energy storage module 415.

[0184] In order to facilitate understanding of the technical solution of the present application, the present application is explained below in conjunction with more detailed embodiments.

[0185] For details, please refer to Figure 1-Figure 8 The main topology of the energy storage system includes a converter valve, a DC direct-connection type energy storage valve and a control device. The DC direct-connection type energy storage valve includes cascaded new energy storage sub-modules, and each new energy storage sub-module is respectively provided with a sub-module controller, and each sub-module controller is respectively connected to the control device.

[0186] In the new energy storage submodule, the new energy component 419 is arranged on the insulating support component and is set up on the placement platform (ground) through the insulating support component. The new energy component 419 is connected to the DC bus 411 between the power module 413 and the second converter 612 through the first converter 417, and the energy storage module 415 is connected to the second converter 612. Specifically, the DC bus 411 includes a first-end DC bus and a second-end DC bus, and the bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1. The first end of the first inductor L1 is connected to the first end of the first switching device Q1 and the first end DC bus, the second end of the first inductor L1 is connected to the energy storage module 415, the second end of the first switching device Q1 is connected to the second-end DC bus and the energy storage module 415, and the third end of the first switching device Q1 is connected to the submodule controller.

[0187] The first converter 417 adopts a non-isolated DC converter, including a first capacitor C1, a second inductor L2, and a second switching device Q2. The first end of the first capacitor C1 is connected to the new energy component 419 and the first end of the second inductor L2, the second end of the second inductor L2 is connected to the first end of the second switching device Q2 and the first end DC bus, the second end of the first capacitor C1 is connected to the new energy component 419 and the second end of the second switching device Q2, the second end of the second switching device Q2 is also connected to the second end DC bus, and the third end of the second switching device Q2 is connected to the sub-module controller.

[0188] Processing logic of the control device under normal operation:

[0189] 1) The new energy output power > the system demand power, the new energy component 419 outputs power to the AC power grid and the energy storage module 415, and the energy storage module 415 is charged (in this case, the power demand of the AC power grid must be met first);

[0190] 2) New energy output power = system demand power, the new energy component 419 outputs power to the AC grid, and the energy storage module 415 neither charges nor discharges;

[0191] 3) The output power of new energy is less than the power required by the system, the new energy component 419 and the energy storage module 415 output power to the AC power grid, and the energy storage module 415 discharges;

[0192] 4) If the new energy component 419 has no output, the energy storage module 415 outputs real-time matching load demand of the AC power grid.

[0193] Processing logic of the control device in special cases:

[0194] 1) If the new energy storage submodule fails and is bypassed, the new energy power output of the module is turned off through the first converter 417;

[0195] 2) If the energy storage module 415 is fully charged, the new energy power output of the module is turned off through the first converter 417 and / or the second converter 612, and the energy storage module 415 is discharged. After the discharge reaches a certain threshold, the new energy component 419 is connected again.

[0196] In the new energy grid-connected system, it is necessary to realize maximum power point tracking control and constant DC voltage control at the same time. In the case where only the first converter 417 exists: for MPPT control, it can be realized by the boost converter (that is, the first converter 417) connected to the new energy component 419, and the specific implementation method is: the submodule controller obtains the DC bus 411 current I_PV (that is, the output current) of the new energy component 419, the voltage U_PV of the second capacitor (that is, the output voltage of the new energy component 419), and uses the MPPT algorithm to find the voltage that can achieve the maximum power output of the new energy component 419 at this time, and outputs it as the reference voltage U_ref. The output reference voltage is compared with the voltage U_PV to obtain an error, which is input into the PI regulator. The output of the PI regulator is the first target duty cycle, and the first switching signal is generated through PWM modulation to realize the voltage closed-loop control of the boost converter, thereby realizing the MPPT control of the new energy component 419. For the DC bus 411 voltage stabilization control, the DC voltage clamping can be directly realized by the voltage of the energy storage battery group S in the parallel energy storage module 415.

[0197] When both the first converter 417 and the second converter 612 exist at the same time: the MPPT control is the same as above, and is implemented by the boost converter connected to the new energy component 419. The DC bus voltage stabilization can be achieved by the boost converter (the second converter 612). The specific implementation method is: the submodule controller obtains a given DC bus voltage reference value U_dc_ref, and makes a difference with the voltage (DC bus voltage) on the DC support capacitor C obtained to obtain the bus voltage error and input it into the PI regulator. The output value of the PI regulator is the second target duty cycle of the boost converter connected to the energy storage module 415. After PWM modulation, a second switching signal is generated to realize the voltage closed-loop control of the DC support capacitor C, thereby realizing the DC bus voltage stabilization control.

[0198] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A new energy storage submodule, characterized in that: include: DC bus; Power module; An energy storage module connected to the power module via the DC bus; A first converter connected to the DC bus; The new energy component is connected to the first converter.

2. The new energy storage submodule according to claim 1, characterized in that: The system further comprises a second converter, which is arranged between the DC bus and the energy storage module and connected to the DC bus and the energy storage module respectively.

3. The new energy storage submodule according to claim 2, characterized in that: The second converter includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

4. The new energy storage submodule according to any one of claims 1 to 3, characterized in that: It also includes an insulating support component, and the new energy component is arranged on the insulating support component.

5. The new energy storage submodule according to claim 4, characterized in that: The first converter comprises a non-isolated DC converter.

6. The new energy storage submodule according to any one of claims 1 to 3, characterized in that: The first converter includes an isolated DC converter.

7. The new energy storage submodule according to claim 1, characterized in that: The system further comprises a third converter, which is arranged between the DC bus and the power module and connected to the DC bus and the power module respectively.

8. The new energy storage submodule according to any one of claims 1 to 7, characterized in that: The new energy components include photovoltaic components.

9. An operating method based on the new energy storage submodule according to any one of claims 1 to 8, characterized in that: include: When the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; When the power supply conditions are met, the power output by the new energy component is converted by the first converter and the power module, and then transmitted to the power grid to supply power to the load.

10. The operating method of the new energy storage submodule according to claim 9, characterized in that: The operation method further comprises: Obtaining output electrical parameters of the new energy component; Determining, based on the output electrical parameters, a target output voltage of the new energy component when operating at maximum power; The first converter is controlled to operate according to the output electrical parameter and the target output voltage.

11. The operating method according to claim 10, characterized in that: The output electrical parameters include output voltage and output current, and determining the target output voltage of the new energy component when operating at maximum power according to the output electrical parameters includes: Perform maximum power point tracking control according to the output voltage and the output current to determine a target output voltage of the new energy component when it is running at maximum power; Controlling the operation of the first converter according to the output electrical parameter and the target output voltage includes: controlling the operation of the first converter according to the output voltage and the target output voltage.

12. The operating method according to claim 11, characterized in that: The step of controlling the first converter to operate according to the output voltage and the target output voltage includes: Determine an output voltage difference by comparing the output voltage with the target output voltage; Performing proportional-integral regulation according to the output voltage difference to determine a first target duty cycle; Pulse width modulation is performed according to the first target duty cycle to generate a first switching signal and send it to the first converter.

13. The operating method according to any one of claims 9 to 12, characterized in that: Also includes: Obtain a DC bus voltage reference value and a DC bus voltage; The DC bus is subjected to voltage stabilization control according to the DC bus voltage reference value and the DC bus voltage.

14. The operating method according to claim 13, characterized in that: The step of performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage comprises: Determine a bus voltage difference by comparing the DC bus voltage reference value with the DC bus voltage; Perform proportional-integral regulation according to the bus voltage difference to determine a second target duty cycle; Pulse width modulation is performed according to the second target duty cycle to generate a second switching signal and send it to the second converter.

15. An energy storage valve, characterized in that: It comprises a submodule controller and the new energy storage submodule according to any one of claims 1 to 8, wherein the submodule controller is communicatively connected to the new energy storage submodule, and each of the new energy storage submodules is cascaded.

16. An energy storage system, characterized in that: It comprises a converter valve and the energy storage valve as claimed in claim 15, wherein the first end and the second end formed by cascading each of the new energy storage submodules are respectively connected to the converter valve, and the converter valve is used to connect to an AC power grid.

17. The energy storage system according to claim 16, characterized in that: The converter valve includes at least one of a voltage source converter valve, a grid-commutated converter valve and a cascade converter valve.

18. An operating method of the energy storage system according to any one of claims 16 to 17, characterized in that: include: When the new energy component has output, obtaining the new energy output power of the new energy component and the system required power of the AC power grid; According to the new energy output power and the system required power, the new energy component is controlled to output electric energy.

19. The operating method according to claim 18, characterized in that: The step of controlling the new energy component to output electric energy according to the new energy output power and the system required power includes: When the output power of the new energy source is greater than the power required by the system, controlling the new energy component to output electric energy to the AC power grid and the energy storage module; When the output power of the new energy is equal to the power required by the system, controlling the new energy component to output electric energy to the AC power grid; When the output power of the new energy source is less than the power required by the system, the new energy component and the energy storage module are controlled to output electric energy to the AC power grid at the same time.

20. The operating method according to claim 18 or 19, characterized in that: Also includes: When the new energy component has no output, the energy storage module is controlled to output electric energy to the AC power grid.

21. The operating method according to any one of claims 18 to 20, characterized in that: Also includes: When the new energy storage submodule is bypassed, the power transmission between the new energy component and the energy storage module is disconnected.

22. The operating method according to any one of claims 18 to 21, characterized in that: Also includes: When the energy storage module is fully charged, disconnecting the power transmission between the new energy component and the energy storage module; When the energy storage module is discharged to a preset power threshold, power transmission between the new energy component and the energy storage module is turned on.

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