Photovoltaic optimizer with energy storage and photovoltaic system

Abstract

The invention provides a photovoltaic optimizer with energy storage, the photovoltaic optimizer is connected with a photovoltaic module, the output end of the photovoltaic optimizer replaces the output of the photovoltaic module, and the photovoltaic optimizer comprises an MPPT circuit used for tracking the maximum output power of the photovoltaic module; the battery pack is connected with the charging and discharging DCDC circuit and is used for storing and releasing electric energy; the charging and discharging DCDC circuit is connected to the output end of the MPPT circuit in parallel and completes charging and discharging control of the battery pack according to a signal of the main control circuit; the main control circuit is used for executing a command issued by a user and uploading data; and the communication circuit is used for forwarding a user instruction to the main control circuit or reporting data acquired by the main control circuit. The battery packs are arranged on the photovoltaic module side, and compared with centralized energy storage, chain reaction of the battery packs can be effectively avoided through scattered installation; and meanwhile, redundant electric energy is stored when power is limited, and is released when power is not limited, so that the utilization rate of light energy is effectively improved, and economic benefits are brought.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic power generation, and in particular to a photovoltaic optimizer with energy storage and a photovoltaic system. Background Art

[0002] Solar photovoltaic power stations, as an important part of the renewable energy field, have been rapidly developed and promoted around the world in recent years. However, photovoltaic power stations have the following problems that are difficult to solve:

[0003] 1. The problem of abandoned photovoltaic power and power rationing: In areas with excellent lighting conditions, photovoltaic power stations often reach peak power generation at noon. However, due to the limitations of the grid's peak-shaving capacity, especially during periods of low electricity demand, a large amount of photovoltaic power cannot be connected to the grid, and power generation is forced to be reduced, resulting in a huge waste of precious resources.

[0004] 2. The problem of unbalanced power generation: Due to the characteristics of natural radiation, the radiation is weak in the morning and evening and the power generation is small, while the radiation is strong at noon and the power generation is large, resulting in excess power generation at noon and insufficient power generation in the morning and evening. Summary of the invention

[0005] In view of the problems existing in the prior art, a photovoltaic optimizer and a photovoltaic system with energy storage are provided. By connecting energy storage batteries in parallel on the output side of the optimizer and controlling them, excess electric energy can be stored when power is limited and released when power is not limited, thereby solving the problems of electric energy waste caused by power limitation in photovoltaic power stations and insufficient power generation in the morning and evening.

[0006] The first aspect of the present invention provides a photovoltaic optimizer with energy storage, wherein the input end of the photovoltaic optimizer is connected to the output end of the photovoltaic module, and the output end of the photovoltaic optimizer replaces the output of the photovoltaic module. The photovoltaic optimizer comprises:

[0007] MPPT (maximum power point tracking) circuit, providing an input end, an output end and a control end, for tracking the maximum output power of the photovoltaic module, wherein the input end of the MPPT circuit serves as the input end of the photovoltaic optimizer, the output end of the MPPT circuit serves as the output end of the photovoltaic optimizer, and the control end of the MPPT circuit is connected to the main control circuit;

[0008] The charge and discharge DCDC circuit is connected in parallel to the output end of the MPPT circuit, connected to the main control circuit, and completes the charge and discharge control of the battery pack according to the signal of the main control circuit;

[0009] The battery pack is connected to the charge and discharge DCDC circuit to store and release electrical energy;

[0010] The main control circuit is used to execute user commands, upload data, and control the MPPT circuit, communication circuit, and charging and discharging DCDC circuit;

[0011] The communication circuit is connected to the main control circuit and is used to forward user instructions to the main control circuit or report data collected by the main control circuit.

[0012] As a preferred solution, it also includes a BMS circuit, which is connected to the battery pack and the main control circuit respectively, and completes the balancing management of the battery pack according to the signal of the main control circuit.

[0013] As a preferred solution, the communication circuit supports wired and wireless communication modes.

[0014] As a preferred solution, the photovoltaic optimizer and the photovoltaic module as a whole only provide one output terminal to the outside.

[0015] As a preferred solution, the charging and discharging DCDC circuit does not work in a default state, that is, the battery pack is neither charging nor discharging.

[0016] As a preferred solution, the working process of the photovoltaic optimizer with energy storage includes:

[0017] When the radiation is strong or the power is limited at noon, the main control circuit controls the charge and discharge DCDC circuit to start working, charging the battery pack to store electric energy;

[0018] When there is no power restriction in the morning and evening, the main control circuit controls the charge and discharge DCDC circuit to start working, and then controls the battery pack to discharge.

[0019] The second aspect of the present invention proposes a photovoltaic system, including a string inverter, multiple photovoltaic modules and multiple photovoltaic optimizers with energy storage as described in the first aspect; the output end of each photovoltaic module is respectively connected to a corresponding photovoltaic optimizer with energy storage, and the output end of each photovoltaic optimizer with energy storage provides two terminals, positive and negative poles. After the positive and negative poles of the output ends of each photovoltaic optimizer are connected in series, they are connected to the input end of the string inverter, and the string inverter converts the DC voltage generated by the photovoltaic module into an AC voltage output.

[0020] Compared with the prior art, the beneficial effects of adopting the above technical solution are:

[0021] 1. Safety: Installing energy storage batteries on photovoltaic panels improves safety compared to centralized energy storage because the battery packs are installed in a dispersed manner and there is no chain reaction.

[0022] 2. Economical and efficient: Storing excess electrical energy during power restrictions and releasing it when power is not restricted effectively improves the utilization rate of light energy and brings economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the photovoltaic optimizer with energy storage proposed in the present invention.

[0024] Figure 2 This is a schematic diagram of the connection between the photovoltaic optimizer and the photovoltaic module proposed in the present invention.

[0025] Figure 3 A schematic diagram of a photovoltaic system using a photovoltaic optimizer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar modules or modules with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be construed as limitations on the present application. On the contrary, the embodiments of the present application include all changes, modifications and equivalents that fall within the spirit and connotation of the appended claims.

[0027] In order to solve the problem of power waste and insufficient power generation in the morning and evening caused by power restriction in photovoltaic power stations, the embodiment of the present invention proposes a photovoltaic optimizer with energy storage, please refer to Figure 2 The photovoltaic optimizer is connected to the output end of the photovoltaic module, and the output end of the photovoltaic optimizer replaces the output of the photovoltaic module. When in use, the photovoltaic module and the photovoltaic optimizer can be regarded as a whole, and the output end of the photovoltaic optimizer is the output end of the whole.

[0028] For details, please refer to Figure 2 The photovoltaic optimizer with energy storage mainly includes MPPT circuit, battery pack, charging and discharging DCDC circuit, main control circuit and communication circuit.

[0029] Among them, the MPPT circuit mainly tracks the maximum output power of the photovoltaic module, and can subsequently implement corresponding control based on the final result. The MPPT circuit has an input end, an output end, and a control end. Its input end is the input end of the photovoltaic optimizer connected to the output end of the photovoltaic module, and its output end is the output end of the photovoltaic optimizer, which is used to achieve overall power output. Its control end is connected to the main control circuit to achieve tracking result interaction.

[0030] In this embodiment, a battery pack is provided in the photovoltaic optimizer, which can effectively store the excess power generated by the photovoltaic components and also provide power output when the photovoltaic power generation is insufficient. Specifically, the battery pack is connected to the charging and discharging DCDC circuit.

[0031] In order to realize the charge and discharge control of the battery pack, in this embodiment, a charge and discharge DCDC circuit is connected in parallel to the output end of the MPPT circuit. The charge and discharge DCDC circuit is connected to the main control circuit at the same time, and the charge and discharge control of the battery pack is realized according to the signal of the main control circuit, that is, the electric energy can flow in both directions. When charging, the electric energy is taken from the electric energy output end of the maximum power tracking circuit and charged into the battery. When discharging, the electric energy is taken from the battery and output from the electric energy output end of the maximum power tracking circuit. The circuit is connected to the main control circuit and controlled by the main control circuit.

[0032] The main control circuit serves as the control core of the photovoltaic optimizer. It is connected to the MPPT circuit, charging and discharging circuit, and communication circuit respectively. It is responsible for receiving and executing user commands and uploading data, as well as controlling the MPPT circuit, communication circuit, and charging and discharging DCDC circuit.

[0033] The communication circuit serves as a node for interaction between the PV optimizer and the user, and is used to forward user instructions to the main control circuit or report data collected by the main control circuit.

[0034] In practical applications, a photovoltaic system is composed of multiple photovoltaic modules, each of which is equipped with a photovoltaic optimizer with energy storage. Therefore, in this embodiment, a BMS circuit is set in the photovoltaic optimizer, which is connected to the battery pack and the main control circuit respectively, and the balancing management of the battery pack is completed according to the signal of the main control circuit.

[0035] In one embodiment, the communication circuit supports both wired and wireless communication.

[0036] This embodiment also provides a specific workflow of the optimizer:

[0037] 1. In the default state, the charge and discharge DCDC circuit does not work, the energy storage battery is neither charging nor discharging, and the maximum power tracking circuit works to track the maximum power output of the photovoltaic module in real time.

[0038] 2. When the radiation is strong or the power is limited at noon, the main control circuit controls the charge and discharge DCDC circuit to start working, charging the battery to store electrical energy.

[0039] 3. When there is no power limit in the morning and evening, the main control circuit controls the charge and discharge DCDC circuit to start working, allowing the battery to discharge and release the stored electrical energy.

[0040] Through the above work flow, the problem of power waste caused by power limitation in photovoltaic power stations and insufficient power generation in the morning and evening can be effectively solved.

[0041] For further information, please refer to Figure 3The present embodiment also provides a photovoltaic system, including a string inverter, a plurality of photovoltaic modules and a plurality of the aforementioned photovoltaic optimizers with energy storage; the output end of each photovoltaic module is respectively connected to a corresponding photovoltaic optimizer with energy storage, and the output end of each photovoltaic optimizer with energy storage provides two terminals, positive and negative poles, and each photovoltaic optimizer with energy storage is connected in series through the positive and negative poles of the output end and then connected to the input end of the string inverter, and the string inverter converts the DC voltage generated by the photovoltaic module into an AC voltage output.

[0042] In this photovoltaic system, energy storage battery packs are installed on the photovoltaic modules. Compared with centralized energy storage, the battery packs are installed in a dispersed manner and there is no chain reaction, which improves safety. At the same time, the excess electric energy is stored during power restrictions and released during non-power restrictions, which effectively improves the utilization rate of light energy and brings economic benefits.

[0043] Example 1

[0044] This embodiment provides a photovoltaic optimizer with energy storage, wherein the input end of the photovoltaic optimizer is connected to the output end of the photovoltaic module, and the output end of the photovoltaic optimizer replaces the output of the photovoltaic module. The photovoltaic optimizer includes:

[0045] MPPT (maximum power point tracking) circuit, providing an input end, an output end and a control end, for tracking the maximum output power of the photovoltaic module, wherein the input end of the MPPT circuit serves as the input end of the photovoltaic optimizer, the output end of the MPPT circuit serves as the output end of the photovoltaic optimizer, and the control end of the MPPT circuit is connected to the main control circuit;

[0046] The charge and discharge DCDC circuit is connected in parallel to the output end of the MPPT circuit, connected to the main control circuit, and completes the charge and discharge control of the battery pack according to the signal of the main control circuit;

[0047] The battery pack is connected to the charging and discharging DCDC circuit;

[0048] The main control circuit is used to execute user commands, upload data, and control the MPPT circuit, communication circuit, and charging and discharging DCDC circuit;

[0049] The communication circuit is connected to the main control circuit and is used to forward user instructions to the main control circuit or report data collected by the main control circuit.

[0050] Example 2

[0051] On the basis of Example 1, this embodiment further includes a BMS circuit, which is connected to the battery pack and the main control circuit respectively, and completes the balancing management of the battery pack according to the signal of the main control circuit.

[0052] Example 3

[0053] On the basis of Embodiment 2, in this embodiment, the communication circuit supports wired and wireless communication modes.

[0054] Example 4

[0055] On the basis of Example 3, in this embodiment, the photovoltaic optimizer and the photovoltaic module as a whole provide only one output terminal to the outside.

[0056] Example 5

[0057] On the basis of Example 4, in this embodiment, the charging and discharging DCDC circuit does not work in a default state, that is, the battery pack is neither charging nor discharging.

[0058] Example 6

[0059] Based on Example 5, in this embodiment, the working process of the photovoltaic optimizer with energy storage includes:

[0060] When the radiation is strong or the power is limited at noon, the main control circuit controls the charge and discharge DCDC circuit to start working, charging the battery pack to store electric energy;

[0061] When there is no power restriction in the morning and evening, the main control circuit controls the charge and discharge DCDC circuit to start working, and then controls the battery pack to discharge.

[0062] Example 7

[0063] This embodiment proposes a photovoltaic system, including a string inverter, multiple photovoltaic modules and multiple photovoltaic optimizers with energy storage described in Embodiment 1; the output end of each photovoltaic module is respectively connected to a corresponding photovoltaic optimizer with energy storage, and the output end of each photovoltaic optimizer with energy storage provides two terminals, positive and negative poles. After the positive and negative poles of the output ends of each photovoltaic optimizer are connected in series, they are connected to the input end of the string inverter, and the string inverter converts the DC voltage generated by the photovoltaic module into an AC voltage output.

[0064] The present invention can be better implemented through the above-mentioned embodiments 1 to 7.

[0065] It should be noted that in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "setting" and "connection" 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 direct connection, or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances; the drawings in the embodiments are used to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations.

[0066] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A photovoltaic optimizer with energy storage, characterized in that: The input end of the photovoltaic optimizer is connected to the output end of the photovoltaic module, and the output end of the photovoltaic optimizer replaces the output of the photovoltaic module. The photovoltaic optimizer includes: The MPPT circuit provides an input end, an output end and a control end, and is used to track the maximum output power of the photovoltaic module, wherein the input end of the MPPT circuit serves as the input end of the photovoltaic optimizer, the output end of the MPPT circuit serves as the output end of the photovoltaic optimizer, and the control end of the MPPT circuit is connected to the main control circuit; The charge and discharge DCDC circuit is connected in parallel to the output end of the MPPT circuit, connected to the main control circuit, and completes the charge and discharge control of the battery pack according to the signal of the main control circuit; The battery pack is connected to the charge and discharge DCDC circuit to store and release electrical energy; The main control circuit is used to execute user commands, upload data, and control the MPPT circuit, communication circuit, and charging and discharging DCDC circuit; The communication circuit is connected to the main control circuit and is used to forward user instructions to the main control circuit or report data collected by the main control circuit.

2. The photovoltaic optimizer with energy storage according to claim 1, characterized in that: It also includes a BMS circuit, which is connected to the battery pack and the main control circuit respectively, and completes the balancing management of the battery pack according to the signal of the main control circuit.

3. The photovoltaic optimizer with energy storage according to claim 2, characterized in that: The communication circuit supports wired and wireless communication.

4. The photovoltaic optimizer with energy storage according to claim 1, characterized in that: The photovoltaic optimizer and the photovoltaic module as a whole only provide one output terminal to the outside.

5. The photovoltaic optimizer with energy storage according to claim 2, characterized in that: The charging and discharging DCDC circuit does not work in a default state, that is, the battery pack is neither charging nor discharging.

6. The photovoltaic optimizer with energy storage according to claim 2, characterized in that: The working process of the photovoltaic optimizer with energy storage includes: When the radiation is strong or the power is limited at noon, the main control circuit controls the charge and discharge DCDC circuit to start working, charging the battery pack to store electric energy; When there is no power restriction in the morning and evening, the main control circuit controls the charge and discharge DCDC circuit to start working, and then controls the battery pack to discharge.

7. A photovoltaic system, characterized in that: It includes a string inverter, multiple photovoltaic modules and multiple photovoltaic optimizers with energy storage as described in any one of claims 1 to 6; the output end of each photovoltaic module is respectively connected to a corresponding photovoltaic optimizer with energy storage, and the output end of each photovoltaic optimizer with energy storage provides two positive and negative terminals. After the positive and negative poles of the output ends of each photovoltaic optimizer with energy storage are connected in series, they are connected to the input end of the string inverter, and the string inverter converts the DC voltage generated by the photovoltaic module into an AC voltage output.

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