Photovoltaic charging and discharging system and method

Abstract

The invention relates to the field of photovoltaic technology, and discloses a photovoltaic charging and discharging system and method, and the system comprises a photovoltaic module, an energy storage device electrically connected with the photovoltaic module, and a remote control platform in communication connection with the energy storage device. According to the invention, the problem that the interaction relationship among the photovoltaic module, the inverter and the power grid is difficult to coordinate in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and specifically to a photovoltaic charging and discharging system and method. Background Art

[0002] With the increasing global demand for clean energy, the development of photovoltaic power stations has become an irreversible trend. However, due to the intermittent and volatile characteristics of photovoltaic power generation (i.e., it can only generate electricity during the day), coupled with factors such as insufficient grid acceptance capacity or fluctuating power demand, some of the generated solar power cannot be effectively utilized and is forced to be abandoned. This not only wastes precious energy resources but also restricts the further development of the photovoltaic industry. To solve the above problems, Photovoltaic with Energy Storage (PV-ES) has become an important development direction in the industry. Traditionally, energy storage systems mostly adopt a centralized layout method, but this has relatively high safety risks and operation and maintenance costs. In recent years, component-level distributed energy storage has been proposed as an innovative solution. It directly installs energy storage batteries near photovoltaic modules, and one small-capacity energy storage device is equipped for every 1 to 4 photovoltaic modules, realizing the near-source storage and management of electric energy, thereby improving the efficiency and safety of the overall system. Despite many advantages, there is still a lack of effective solutions for how to achieve efficient charge and discharge control in this new energy storage mode, especially how to coordinate the interaction relationship among photovoltaic modules, inverters, and the power grid. Summary of the Invention

[0003] To overcome the deficiencies of the prior art, the present invention provides a photovoltaic charging and discharging system and method, which solves the problems in the prior art such as the difficulty in coordinating the interaction relationship among photovoltaic modules, inverters, and the power grid.

[0004] The technical solutions adopted by the present invention to solve the above problems are as follows:

[0005] A photovoltaic charging and discharging system includes a photovoltaic module, an energy storage device electrically connected to the photovoltaic module, and a remote control platform communicatively connected to the energy storage device.

[0006] As a preferred technical solution, it includes an inverter electrically connected to the energy storage device, and the inverter is used to be electrically connected to the power grid.

[0007] As a preferred technical solution, the remote control platform can send charge and discharge commands to the energy storage device by means of broadcast, multicast, or unicast.

[0008] As a preferred technical solution, the remote control platform can send the following charge and discharge commands to the energy storage device: energy storage priority charging command, grid priority charging command, discharge command, end command:

[0009] Among them, when the energy storage priority charging command is issued, the electricity generated by the photovoltaic modules is preferentially used for the energy storage device, and the remaining electricity is input into the power grid through the inverter; when the grid priority charging command is issued, the electricity generated by the photovoltaic modules is preferentially sent to the power grid through the inverter, and the remaining electricity is input into the energy storage device.

[0010] As a preferred technical solution, the energy storage device has a timeout mechanism when executing charge and discharge commands: when the energy storage device does not receive a charge and discharge command after exceeding the set time, it automatically stops charging and discharging until it receives a charge and discharge command again.

[0011] As a preferred technical solution, the energy storage device can independently output electric energy to the power grid through an inverter.

[0012] As a preferred technical solution, each energy storage device has the ability to detect abnormalities, detect its own temperature and working status, and automatically exits charge and discharge when an abnormality is detected and no longer executes the control platform instructions.

[0013] As a preferred technical solution, the energy storage device includes a battery management system, and the battery management system is used to: make the energy storage device automatically stop charging when it is fully charged and no longer execute the instructions of the control platform.

[0014] As a preferred technical solution, the battery management system is used to: make the energy storage device automatically end discharging when it is discharged and no longer execute the instructions of the control platform.

[0015] A photovoltaic charge and discharge method uses the described photovoltaic charge and discharge system to charge or discharge an energy storage device.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention can optimize the collaborative work among photovoltaic modules, inverters and energy storage devices, improve the photovoltaic power generation efficiency, reduce the phenomenon of abandoned light, and enhance the stability and reliability of the power system

[0018] (2) The present invention effectively solves the charge and discharge control problem of energy storage at the photovoltaic module level and effectively realizes the peak shaving and valley filling of electric energy generated by photovoltaic power generation. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the connection relationship between the energy storage device and the photovoltaic module;

[0020] Figure 2 It is a schematic diagram of the structure of the energy storage system based on the photovoltaic module level;

[0021] Figure 3 It is a schematic diagram of peak shaving and valley filling of electric energy with discharging in the morning and evening and charging at noon;

[0022] Figure 4 It is an example diagram for dividing charge and discharge time;

[0023] Figure 5 It is a conversion diagram of charge and discharge control states of an energy storage device. Specific implementation manners

[0024] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings, but the implementation manners of the present invention are not limited thereto.

[0025] Embodiment 1

[0026] As Figures 1 to 5 shown, a photovoltaic charge and discharge system includes a photovoltaic module, an energy storage device electrically connected to the photovoltaic module, and a remote control platform communicatively connected to the energy storage device.

[0027] As a preferred technical solution, it includes an inverter electrically connected to the energy storage device, and the inverter is used to be electrically connected to the power grid.

[0028] The present invention can optimize the collaborative work among the photovoltaic module, the inverter, and the energy storage device, realize peak shaving and valley filling of electric energy, improve the photovoltaic power generation efficiency, reduce the phenomenon of light abandonment, and enhance the stability and reliability of the power system.

[0029] As a preferred technical solution, the remote control platform can send charge and discharge commands to the energy storage device in the way of broadcast, multicast or unicast.

[0030] Its function is: to send charge and discharge commands to the energy storage device in the way of broadcast, multicast or unicast, so as to realize the charge and discharge control of each energy storage device by the remote control platform.

[0031] As a preferred technical solution, the remote control platform can send the following charge and discharge commands to the energy storage device: energy storage priority charging command, grid priority charging command, discharge command, end command:

[0032] Among them, when the energy storage priority charging command is sent, the electricity generated by the photovoltaic module is preferentially used for the energy storage device, and the remaining electricity is input into the power grid through the inverter; when the grid priority charging command is sent, the electricity generated by the photovoltaic module is preferentially sent to the power grid through the inverter, and the remaining electricity is input into the energy storage device.

[0033] The present invention effectively solves the charge and discharge control problem of photovoltaic module-level energy storage and effectively realizes peak shaving and valley filling of photovoltaic power generation.

[0034] As a preferred technical solution, the energy storage device has a timeout mechanism when executing charge and discharge commands: when the energy storage device does not receive a charge and discharge command after exceeding the set time, it automatically stops charging and discharging until it receives a charge and discharge command again.

[0035] This improves the safety of the energy storage device.

[0036] As a preferred technical solution, the energy storage device can independently output electric energy to the power grid through an inverter.

[0037] This facilitates the energy storage device to output electric energy to the power grid through the inverter at night.

[0038] As a preferred technical solution, each energy storage device has the ability to detect abnormalities, detect its own temperature and working status, and automatically exit the charge and discharge when an abnormality is detected, and no longer execute the instructions of the control platform.

[0039] Its function is: This improves the safety of the energy storage device.

[0040] As a preferred technical solution, the energy storage device includes a battery management system, and the battery management system is used to: automatically stop charging the energy storage device when it is fully charged, and no longer execute the instructions of the control platform.

[0041] As a preferred technical solution, the battery management system is used to: automatically end the discharge of the energy storage device when it is discharged, and no longer execute the instructions of the control platform.

[0042] The battery management system realizes the automatic stop function of charge and discharge, which is beneficial to saving electric energy and also improves the safety of the energy storage device.

[0043] A photovoltaic charge and discharge method uses the described photovoltaic charge and discharge system to charge or discharge photovoltaic modules.

[0044] The present invention can optimize the collaborative work among photovoltaic modules, inverters, and energy storage devices, improve the photovoltaic power generation efficiency, reduce the phenomenon of light abandonment, and enhance the stability and reliability of the power system; the present invention effectively solves the charge and discharge control problem of component-level energy storage for photovoltaic power generation and effectively realizes the peak shaving and valley filling of electric energy generated by photovoltaic power generation.

[0045] Embodiment 2

[0046] As Figures 1 to 5 shown, on the basis of Embodiment 1, this embodiment provides a more refined implementation method.

[0047] The present invention relates to an intelligent charge and discharge strategy applied to a component-level distributed energy storage photovoltaic power station, and this strategy can optimize the collaborative work among photovoltaic modules, inverters, and energy storage devices, improve the photovoltaic power generation efficiency, reduce the phenomenon of light abandonment, and enhance the stability and reliability of the power system. Figure 1 Among them, the photovoltaic module includes photovoltaic components (including photovoltaic cells, etc.) and energy storage devices.

[0048] The present invention can be used in centralized photovoltaic power stations to solve the problem of power curtailment.

[0049] The present invention relates to a photovoltaic module, an inverter, an energy storage device, a power grid, and a remote control platform.

[0050] The remote control platform can communicate with each energy storage device, and the remote control platform can send commands to the energy storage device in the form of broadcast, multicast or unicast.

[0051] The remote control platform can send commands such as energy storage priority charging command, grid priority charging command, discharging command, and ending command to the energy storage device.

[0052] During use, select the energy storage device to be controlled, and configure one or more charging time periods and one or more discharging time periods on the remote control platform every day according to the local light characteristics and the power consumption of the power grid. Repeatedly send charging commands during the charging time period, and send discharging commands during the discharging time period.

[0053] The energy storage device has a timeout mechanism when executing charging and discharging commands. It automatically stops charging and discharging after a certain period of time without receiving a command until it receives a command again.

[0054] Different energy storage devices can have different charging and discharging strategies at the same time.

[0055] Two strategies can be selected during the charging time period: grid priority power consumption or energy storage priority power consumption. When the grid priority power consumption, the electricity generated by the photovoltaic module is first transmitted to the power grid through the inverter, and the remaining electricity is used for energy storage. Energy storage priority power consumption means that the electricity generated by the photovoltaic module is first used for the energy storage device, and the remaining electric energy is input into the power grid through the inverter.

[0056] During the discharging time period, the photovoltaic module and the energy storage device simultaneously output electric energy to the power grid through the inverter. The energy storage device outputs electric energy to the power grid through the inverter to form a power transmission branch, and the photovoltaic module outputs electric energy to the power grid through the energy storage device connected to the inverter (at this time, the energy storage device is equivalent to a power transmission line) to form another parallel power transmission branch, which is convenient to increase the electric energy output to the power grid in the morning and other situations where the light conditions are insufficient and the power of the photovoltaic module is insufficient.

[0057] If the discharging time period is at night, the energy storage device can output electric energy to the power grid alone through the inverter.

[0058] Each energy storage device has an independent Battery Management System (BMS for short). It automatically stops charging when fully charged and automatically ends discharging and no longer executes the instructions of the control platform when the battery is emptied.

[0059] Each energy storage device has the ability to detect abnormalities, detect its own temperature and working status, and automatically exits charging and discharging when an abnormality is detected and no longer executes the instructions of the control platform.

[0060] The present invention has the following technical effects:

[0061] (1) The present invention can optimize the collaborative work among photovoltaic modules, inverters, and energy storage devices, improve the photovoltaic power generation efficiency, reduce the phenomenon of light abandonment, and enhance the stability and reliability of the power system;

[0062] (2) The present invention effectively solves the charge-discharge control problem of energy storage at the photovoltaic module level and effectively realizes the peak shaving and valley filling of the electric energy generated by photovoltaic power generation.

[0063] As described above, the present invention can be preferably realized.

[0064] All the features disclosed in all the embodiments in this specification, or all the steps in the methods or processes implicitly disclosed, except for the mutually exclusive features and / or steps, can be combined and / or extended and replaced in any way.

[0065] The above is only a preferred embodiment of the present invention, and does not impose any formal limitations on the present invention. Based on the technical essence of the present invention, any simple modifications, equivalent replacements, and improvements made to the above embodiments within the spirit and principles of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A photovoltaic charging and discharging system, characterized in that: It includes a photovoltaic module, an energy storage device electrically connected to the photovoltaic module, and a remote control platform communicatively connected to the energy storage device.

2. A photovoltaic charging and discharging system according to claim 1, characterized in that: It includes an inverter electrically connected to the energy storage device, and the inverter is used to be electrically connected to the power grid.

3. A photovoltaic charging and discharging system according to claim 2, characterized in that: The remote control platform can send charging and discharging commands to the energy storage device through broadcast, multicast or unicast.

4. A photovoltaic charging and discharging system according to claim 3, characterized in that: The remote control platform can send the following charging and discharging commands to the energy storage device: energy storage priority charging command, grid priority charging command, discharge command, and end command: Among them, when the energy storage priority charging command is issued, the electricity generated by the photovoltaic modules is used for energy storage equipment first, and the remaining electricity is input into the grid through the inverter; when the power grid priority charging command is issued, the electricity generated by the photovoltaic modules is first input into the grid through the inverter, and the remaining electricity is input into the energy storage device.

5. A photovoltaic charging and discharging system according to claim 3, characterized in that: The energy storage device has a timeout mechanism for executing charge and discharge commands: when the energy storage device does not receive a charge and discharge command within the set time, it automatically stops charging and discharging until it receives a charge and discharge command again.

6. A photovoltaic charging and discharging system according to claim 3, characterized in that: The energy storage device can output electrical energy to the grid through an inverter alone.

7. A photovoltaic charging and discharging system according to claim 3, characterized in that: Each energy storage device has the ability to detect abnormalities, detect its own temperature and working status, and automatically exit charging and discharging when an abnormality is detected, and no longer executes the control platform instructions.

8. A photovoltaic charging and discharging system according to any one of claims 2 to 7, characterized in that: The energy storage device includes a battery management system, which is used to automatically stop charging the energy storage device when it is fully charged and no longer execute the instructions of the control platform.

9. A photovoltaic charging and discharging system according to claim 8, characterized in that: The battery management system is used to automatically terminate the discharge of the energy storage device when it is empty and no longer execute the instructions of the control platform.

10. A photovoltaic charging and discharging method, characterized in that: A photovoltaic charging and discharging system as described in any one of claims 1 to 9 is used to charge or discharge an energy storage device.

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