Photovoltaic system

Abstract

The embodiment of the invention discloses a photovoltaic system. The photovoltaic system comprises a main control module, an energy storage module and a plurality of component control modules, at least one photovoltaic module is connected with one module control module, and the main control module, each module control module and the energy storage module are all connected with the direct current bus; the component control module is used for converting direct current output by the photovoltaic component into direct current in a safe voltage range, and the main control module is used for starting the specified component control module to operate according to the operation states of the energy storage module and the power grid and setting the operation parameters of the operating component control module. According to the scheme, the photovoltaic module is mounted on the direct current bus for transmitting the direct current within the safe voltage range through the module control module, the installation flexibility of the photovoltaic module is improved, the safety of the photovoltaic system is improved, direct current coupling and integration of the energy storage module are facilitated, and the manufacturing cost of the photovoltaic system is reduced.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of photovoltaic technology, and in particular to a photovoltaic system. Background Art

[0002] Currently, there are three main types of PV module-level power electronic devices: microinverters, optimizers, and rapid shutdown devices. Rapid shutdown devices only address the safety issues of PV DC high voltage and cannot provide module-level PV power generation control. Rapid shutdown devices manage power generation at the string level. Compared to optimizers, microinverters have advantages such as no DC high voltage and flexible installation. However, they have disadvantages such as high cost and difficulty integrating with energy storage (because energy storage batteries operate on DC power, while microinverters output AC power, they can only be AC-coupled, not DC-coupled). Optimizers are much cheaper and allow for cost-effective integration of energy storage. However, the strings they form have high voltages during operation and have string length requirements, which must be neither too short nor too long. Compared to microinverters, they are also less flexible. In summary, microinverters have the disadvantages of high cost, while optimizers have the disadvantages of low operational safety and limited flexibility. Summary of the Invention

[0003] The embodiment of the present invention provides a photovoltaic system to improve the safety and flexibility of photovoltaic module power generation control and reduce the cost of the photovoltaic system.

[0004] An embodiment of the present invention provides a photovoltaic system, which includes a main control module, an energy storage module, and multiple component control modules;

[0005] At least one photovoltaic module is connected to a module control module, and the main control module, each module control module and the energy storage module are all connected to a DC bus;

[0006] The component control module is used to convert the direct current output by the photovoltaic component into direct current within a safe voltage range. The main control module is used to start the operation of the specified component control module according to the operating status of the energy storage module and the power grid, and set the operating parameters of the running component control module.

[0007] Optionally, the component control module includes a voltage conversion unit and a protection unit;

[0008] At least one photovoltaic module is connected to the input end of the voltage conversion unit, the first output end of the voltage conversion unit is connected to the DC bus through the protection unit, and the second output end of the voltage conversion unit is connected to the DC bus;

[0009] The voltage conversion unit is used to convert the voltage of the direct current output by the photovoltaic module into direct current within a safe voltage range; the protection unit is used to control the conduction state of the voltage conversion unit and the DC bus connection circuit.

[0010] Optionally, the voltage conversion unit includes at least one DCDC converter;

[0011] The first and second ends of each of the DCDC converters serve as input ends of the voltage conversion unit, the third end of each of the DCDC converters is connected and serves as the first output end of the voltage conversion unit, and the fourth end of each of the DCDC converters is connected and serves as the second output end of the voltage conversion unit.

[0012] Optionally, the component control module further includes a control unit;

[0013] The voltage conversion unit and the protection unit are both connected to the control unit, and the control unit is used to control the voltage conversion unit to perform voltage conversion and control the protection unit to switch on or off the connection loop between the voltage conversion unit and the DC bus.

[0014] Optionally, the protection unit includes a transistor;

[0015] The gate of the transistor is connected to the control unit, the first electrode of the transistor is connected to the first output end of the voltage conversion unit, and the second electrode of the transistor is connected to the DC bus.

[0016] Optionally, the component control module further includes a communication unit;

[0017] The communication unit is connected to the control unit, and the control unit is used to communicate with the control unit via the communication unit.

[0018] Optionally, the photovoltaic system further includes an inverter module;

[0019] The DC bus is connected to the power grid through the inverter module. The inverter module is used to convert the DC power transmitted by the DC bus into AC power, or convert the AC power transmitted by the power grid into DC power.

[0020] Optionally, the inverter module includes at least one bidirectional inverter;

[0021] A first end of each bidirectional inverter is connected to the DC bus, and a second end of each bidirectional inverter is connected to the power grid.

[0022] Optionally, the energy storage module includes at least one energy storage battery;

[0023] Each of the energy storage batteries is connected to the DC bus.

[0024] In the photovoltaic system provided by the embodiments of the present invention, photovoltaic modules are mounted on a DC bus via a module control module, making installation of the photovoltaic modules more flexible. The module control module can convert the DC power output by the photovoltaic modules into DC power within a safe voltage range, thereby ensuring that the DC power transmitted by the DC bus is within the safe voltage range. This enhances the safety of the photovoltaic system and facilitates DC coupling with integrated energy storage modules. Furthermore, this solution, which uses a module control module to mount photovoltaic modules on a DC bus, significantly reduces the cost of the photovoltaic system compared to the prior art method of mounting photovoltaic modules on a power grid using microinverters. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic structural diagram of a photovoltaic system provided by an embodiment of the present invention;

[0027] Figure 2 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0028] Figure 3 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0029] Figure 4 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0030] Figure 5 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0031] Figure 6 A schematic diagram of the structure of a Buckboost circuit connected to a transistor according to an embodiment of the present invention;

[0032] Figure 7 A schematic diagram of another Buckboost circuit connected to a transistor according to an embodiment of the present invention;

[0033] Figure 8 A schematic diagram of another Buckboost circuit connected to a transistor according to an embodiment of the present invention;

[0034] Figure 9A schematic diagram of the structure of a Buck circuit and a transistor connected according to an embodiment of the present invention;

[0035] Figure 10 A schematic diagram of the structure of another Buck circuit connected to a transistor according to an embodiment of the present invention;

[0036] Figure 11 A schematic diagram of the structure of a Boost circuit and a transistor connected according to an embodiment of the present invention;

[0037] Figure 12 A schematic structural diagram of another Boost circuit and transistor connection provided by an embodiment of the present invention;

[0038] Figure 13 A schematic structural diagram of another Boost circuit and transistor connection provided by an embodiment of the present invention;

[0039] Figure 14 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0040] Figure 15 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention;

[0041] Figure 16 A schematic structural diagram of another photovoltaic system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] Figure 1 A schematic diagram of the structure of a photovoltaic system provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the photovoltaic system includes a main control module 110, an energy storage module 120 and a plurality of component control modules 130;

[0045] At least one photovoltaic module 01 is connected to a module control module 130 , and the main control module 110 , each module control module 130 , and the energy storage module 120 are all connected to a DC bus DC;

[0046] The component control module 130 is used to convert the direct current output by the photovoltaic component 01 into direct current within a safe voltage range. The main control module 110 is used to start the operation of the specified component control module 130 according to the operating status of the energy storage module 120 and the power grid, and set the operating parameters of the running component control module 130.

[0047] Among them, the main control module 110 is the control center of the photovoltaic system, which can communicate with the energy storage module 120, the power grid and each component control module 130 to monitor and control the energy storage module 120, the power grid and each component control module 130. The energy storage module 120 can store electrical energy or output electrical energy. The photovoltaic component 01 can convert light energy into electrical energy. The component control module 130 can convert the direct current generated by the photovoltaic component 01 into direct current below the human safety level. In the photovoltaic industry, 80V is generally considered to be the dividing line. A direct current voltage higher than 80V is likely to cause electric shock risks to people and is prone to generating direct current arcs. Therefore, the safe voltage range is less than or equal to 80V. During the operation of the photovoltaic system, the voltage of the output direct current converted by each component control module 130 is equal.

[0048] Based on the aforementioned connection relationships, the operating process of the photovoltaic system is explained below: the main control module 110 obtains the operating status of the energy storage module 120 and the power grid (e.g., the power demand of the energy storage module 120 and the power grid). Based on the operating status of the energy storage module 120 and the power grid, it selects a designated component control module 130 for activation and simultaneously sets operating parameters such as the maximum current, maximum voltage, or maximum power for the active component control module 130. After activation, the designated component control module 130 converts the voltage output by the photovoltaic module 01 into direct current (DC) within a safe voltage range, based on the operating parameters set by the main control module 110, and transmits the DC bus DC to power the energy storage module 120 and the power grid. Alternatively, it transmits the power output by the energy storage module 120 or the power grid to the DC bus DC to power the photovoltaic module 01 (e.g., if the photovoltaic module 01 is covered with snow, the photovoltaic module 01 is powered so that the heat generated by the photovoltaic module 01 can be used to clear the snow).

[0049] In the photovoltaic system provided by the embodiment of the present invention, photovoltaic modules 01 are mounted on a DC bus DC via module control module 130, making the installation of photovoltaic modules 01 more flexible. Module control module 130 can convert the DC power output by photovoltaic modules 01 into DC power within a safe voltage range, thereby ensuring that the DC power transmitted by the DC bus DC is within a safe voltage range. This enhances the safety of the photovoltaic system and facilitates DC coupling with the integrated energy storage module 120. Furthermore, this solution utilizes module control module 130 to mount photovoltaic modules 01 on the DC bus DC, significantly reducing the cost of the photovoltaic system compared to the prior art method of mounting photovoltaic modules 01 on the power grid using microinverters.

[0050] Based on the above embodiment, optionally, Figure 2 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 2 As shown, the component control module 130 includes a voltage conversion unit 131 and a protection unit 132;

[0051] At least one photovoltaic module 01 is connected to the input end of the voltage conversion unit 131, the first output end of the voltage conversion unit 131 is connected to the DC bus DC through the protection unit 132, and the second output end of the voltage conversion unit 131 is connected to the DC bus DC; the voltage conversion unit 131 is used to convert the voltage of the DC power output by the photovoltaic module 01 into DC power within a safe voltage range; the protection unit 132 is used to control the conduction state of the connection circuit between the voltage conversion unit 131 and the DC bus DC.

[0052] During on-site installation and wiring of the photovoltaic system, if the positive and negative poles of voltage conversion unit 131 are connected incorrectly to the DC bus (DC), protection unit 132 can protect voltage conversion unit 131 by disconnecting the circuit connecting voltage conversion unit 131 to the DC bus (DC). After staff verify and modify the connection between the positive and negative poles of voltage conversion unit 131 and the DC bus (DC), protection unit 132 can connect the circuit connecting voltage conversion unit 131 to the DC bus (DC). This prevents damage to voltage conversion unit 131.

[0053] If the voltage conversion unit 131 is damaged, the protection unit 132 can control the connection loop between the voltage conversion unit 131 and the DC bus DC to be disconnected, so that the voltage conversion unit 131 does not work, thereby avoiding the occurrence of safety accidents caused by the damage of the voltage conversion unit 131.

[0054] In addition, the protection unit 132 can also serve as a start or shut-down switch for the voltage conversion unit 131 , that is, the protection unit 132 controls the start or shut-down of the voltage conversion unit 131 by controlling the conduction state of the connection loop between the voltage conversion unit 131 and the DC bus DC.

[0055] Based on the above embodiment, optionally, Figure 3 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 3 As shown, the voltage conversion unit 131 includes at least one DCDC converter 1311;

[0056] The first and second ends of each DCDC converter 1311 serve as input ends of the voltage conversion unit 131, the third end of each DCDC converter 1311 is connected and serves as the first output end of the voltage conversion unit 131, and the fourth end of each DCDC converter 1311 is connected and serves as the second output end of the voltage conversion unit 131.

[0057] in, Figure 3 The circuit includes two DC-DC converters 1311. The third terminal of each DC-DC converter 1311 is a positive output terminal, which is connected to the DC bus positive terminal DC+ through the protection unit 132. The fourth terminal of each DC-DC converter 1311 is a negative output terminal, which is connected to the DC bus negative terminal DC-. Furthermore, when the third terminal of each DC-DC converter 1311 is a negative output terminal, it can be connected to the DC bus negative terminal DC- through the protection unit 132. The fourth terminal of each DC-DC converter 1311 is a positive output terminal, which is connected to the DC bus positive terminal DC+.

[0058] In addition, the voltage conversion unit 131 includes at least one DCDC converter 1311 , which has the advantage of low cost compared to the prior art using a micro inverter.

[0059] Based on the above embodiment, optionally, Figure 4 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 4 As shown, the component control module 130 further includes a control unit 133;

[0060] The voltage conversion unit 131 and the protection unit 132 are both connected to the control unit 133. The control unit 133 is used to control the voltage conversion unit 131 to perform voltage conversion and control the protection unit 132 to open or close the connection loop between the voltage conversion unit 131 and the DC bus DC.

[0061] Among them, the control module is the control center of the component control module 130, which can send control instructions to the voltage conversion unit 131 and the protection unit 132, so that the voltage conversion unit 131 performs voltage conversion and the protection unit 132 turns on or off the connection circuit between the voltage conversion unit 131 and the DC bus DC.

[0062] Based on the above embodiment, optionally, Figure 5 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 5 As shown, the protection unit 132 includes a transistor T; a gate of the transistor T is connected to the control unit 133 , a first electrode of the transistor T is connected to the first output end of the voltage conversion unit 131 , and a second electrode of the transistor T is connected to the DC bus DC.

[0063] The transistor T includes an N-type MOS transistor or a P-type MOS transistor.

[0064] If the transistor T is an N-type MOS transistor, the control module provides a high level to the gate of the N-type MOS transistor, the first and second electrodes of the N-type MOS transistor are conductive, and the voltage conversion unit 131 is conductive to the DC bus DC connection loop; the control module provides a low level to the gate of the N-type MOS transistor, the first and second electrodes of the N-type MOS transistor are disconnected, and the voltage conversion unit 131 is disconnected from the DC bus DC connection loop.

[0065] If the transistor T is a P-type MOS transistor, the control module provides a high level to the gate of the P-type MOS transistor, the first and second electrodes of the P-type MOS transistor are disconnected, and the voltage conversion unit 131 and the DC bus DC connection loop are disconnected; the control module provides a low level to the gate of the P-type MOS transistor, the first and second electrodes of the P-type MOS transistor are connected, and the voltage conversion unit 131 and the DC bus DC connection loop are connected.

[0066] If the first output terminal of the voltage conversion unit 131 is a positive output terminal, the second electrode of the transistor T is connected to the positive electrode DC+ of the DC bus; if the first output terminal of the voltage conversion unit 131 is a negative output terminal, the second electrode of the transistor T is connected to the negative electrode DC- of the DC bus.

[0067] Optionally, the DCDC converter 1311 includes a Buckboost circuit, a Buck circuit, and a Boost circuit.

[0068] Figure 6 A schematic diagram of a Buckboost circuit connected to a transistor according to an embodiment of the present invention is provided. Figure 7 A schematic diagram of another Buckboost circuit connected to a transistor according to an embodiment of the present invention is provided. Figure 8 A schematic diagram of the structure of another Buckboost circuit connected to a transistor according to an embodiment of the present invention.

[0069] Figure 6 The Buckboost circuit has a common cathode, and the positive output terminal of the Buckboost circuit is connected to the first electrode of the transistor T. Figure 7 The Buckboost circuit has a common cathode, and the negative output terminal of the Buckboost circuit is connected to the first electrode of the transistor T. Figure 8 The Buckboost circuit has a common anode, and the negative output terminal of the Buckboost circuit is connected to the first electrode of the transistor T.

[0070] contrast Figure 6-Figure 8 As you can see, transistor T can be connected to either the positive or negative output of the Buckboost circuit, regardless of whether the Buckboost circuit has a common anode or cathode. The same applies to Buck and Boost circuits, so we won't compare them here.

[0071] Figure 9 A schematic diagram of a Buck circuit and a transistor connected to each other according to an embodiment of the present invention is provided. Figure 10 A schematic diagram of the structure of another Buck circuit connected to a transistor provided by an embodiment of the present invention.

[0072] Figure 9 The Buck circuit has a common cathode, and the negative output terminal of the Buck circuit is connected to the first electrode of the transistor T. Figure 10 The Buck circuit has a common anode, and the negative output terminal of the Buck circuit is connected to the first electrode of the transistor T.

[0073] Figure 11 A schematic diagram of a structure of a Boost circuit connected to a transistor according to an embodiment of the present invention is provided. Figure 12 This is a structural diagram of another Boost circuit connected to a transistor provided by an embodiment of the present invention. Figure 13 This is a structural diagram of another Boost circuit connected to a transistor provided by an embodiment of the present invention.

[0074] Figure 11 The boost circuit has a common cathode, and the negative output terminal of the boost circuit is connected to the first electrode of the transistor T. Figure 12 The Boost circuit has a common anode, and the negative output terminal of the Boost circuit is connected to the first electrode of the transistor T. Figure 13 The two common cathode Boost circuits are connected in parallel, and the negative output terminal of the parallel Boost circuit is connected to the first electrode of the transistor T.

[0075] Based on the above embodiment, optionally, Figure 14 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 14As shown, the component control module 130 further includes a communication unit 134 ; the communication unit 134 is connected to the control unit 133 , and the control unit 133 is configured to communicate with the control unit 133 via the communication unit 134 .

[0076] The control unit 133 can communicate with the main control module 110 via the communication unit 134 , so that the control unit 133 can obtain instructions sent by the main control module 110 or send the operating status of the photovoltaic assembly 01 to the main control module 110 .

[0077] Based on the above embodiment, optionally, Figure 15 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 15 The photovoltaic system shown also includes an inverter module 140;

[0078] The DC bus DC is connected to the power grid AC through the inverter module 140 . The inverter module 140 is used to convert the DC power transmitted by the DC bus DC into AC power, or convert the AC power transmitted by the power grid AC into DC power.

[0079] Specifically, Figure 16 A schematic diagram of another photovoltaic system according to an embodiment of the present invention is shown in FIG. Figure 16 As shown, the inverter module 140 includes at least one bidirectional inverter 141 ; a first end of each bidirectional inverter 141 is connected to a DC bus DC, and a second end of each bidirectional inverter 141 is connected to a power grid AC.

[0080] Among them, providing multiple bidirectional inverters 141 can enhance the reliability of the photovoltaic system, so that when a bidirectional inverter 141 is damaged, the remaining bidirectional inverters 141 can still maintain the normal operation of the photovoltaic system.

[0081] Based on the above embodiment, the energy storage module 120 includes at least one energy storage battery; each energy storage battery is connected to the direct current bus DC.

[0082] The component control module 130 can convert the DC power output by the photovoltaic component 01 into DC power within a safe voltage range, thereby facilitating DC coupling of the integrated energy storage battery so that the energy storage battery can be connected to the DC bus DC.

[0083] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0084] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A photovoltaic system, characterized in that: Includes main control module, energy storage module and multiple component control modules; At least one photovoltaic module is connected to a module control module, and the main control module, each module control module and the energy storage module are all connected to a DC bus; The component control module is used to convert the direct current output by the photovoltaic component into direct current within a safe voltage range. The main control module is used to start the operation of the specified component control module according to the operating status of the energy storage module and the power grid, and set the operating parameters of the running component control module.

2. The photovoltaic system according to claim 1, characterized in that: The component control module includes a voltage conversion unit and a protection unit; At least one photovoltaic module is connected to the input end of the voltage conversion unit, the first output end of the voltage conversion unit is connected to the DC bus through the protection unit, and the second output end of the voltage conversion unit is connected to the DC bus; The voltage conversion unit is used to convert the voltage of the direct current output by the photovoltaic module into direct current within a safe voltage range; the protection unit is used to control the conduction state of the voltage conversion unit and the DC bus connection circuit.

3. The photovoltaic system according to claim 2, characterized in that: The voltage conversion unit includes at least one DCDC converter; The first and second ends of each of the DCDC converters serve as input ends of the voltage conversion unit, the third end of each of the DCDC converters is connected and serves as the first output end of the voltage conversion unit, and the fourth end of each of the DCDC converters is connected and serves as the second output end of the voltage conversion unit.

4. The photovoltaic system according to claim 2, characterized in that: The component control module further includes a control unit; The voltage conversion unit and the protection unit are both connected to the control unit, and the control unit is used to control the voltage conversion unit to perform voltage conversion and control the protection unit to switch on or off the connection loop between the voltage conversion unit and the DC bus.

5. The photovoltaic system according to claim 4, characterized in that: The protection unit includes a transistor; The gate of the transistor is connected to the control unit, the first electrode of the transistor is connected to the first output end of the voltage conversion unit, and the second electrode of the transistor is connected to the DC bus.

6. The photovoltaic system according to claim 4, characterized in that: The component control module also includes a communication unit; The communication unit is connected to the control unit, and the control unit is used to communicate with the control unit via the communication unit.

7. The photovoltaic system according to any one of claims 1 to 6, characterized in that: Also includes inverter module; The DC bus is connected to the power grid through the inverter module. The inverter module is used to convert the DC power transmitted by the DC bus into AC power, or convert the AC power transmitted by the power grid into DC power.

8. The photovoltaic system according to claim 7, characterized in that: The inverter module includes at least one bidirectional inverter; A first end of each bidirectional inverter is connected to the DC bus, and a second end of each bidirectional inverter is connected to the power grid.

9. The photovoltaic system according to claim 1, characterized in that: The energy storage module includes at least one energy storage battery; Each of the energy storage batteries is connected to the DC bus.

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