A grid-connected and off-grid photovoltaic energy storage charging system and charging control method

Abstract

A grid-connected and off-grid photovoltaic energy storage and charging system comprises: an energy storage module comprising at least two energy storage devices for storing electrical energy; a photovoltaic power generation module for converting solar energy into electrical energy and transmitting it to the energy storage devices; an grid-connected and off-grid module for controlling the grid connection or off-grid connection of the energy storage module; a charging module for transmitting the electrical energy stored in the energy storage device to a powered device; and an energy storage management module for controlling the energy storage module, the photovoltaic power generation module, and the charging module. The present invention provides a grid-connected and off-grid photovoltaic energy storage and charging system and charging control method, which can stably charge powered devices, avoid interference with the main power grid, and provide good economic benefits.

Description

Technical Field

[0001] The present invention relates to the field of chargers, and in particular to an on-grid and off-grid photovoltaic energy storage charging system and a charging control method. Background Art

[0002] With increasing attention being paid to energy crises and environmental pollution, energy-saving and environmentally friendly electric vehicles have become the global automotive industry's development trend. Promoting the integration of electric vehicles into daily life requires first addressing the issue of charging. Directly connecting electric vehicles to the main power grid for charging significantly increases the load on the power system. To mitigate this impact on the main grid, a viable solution is to build independently operated, off-grid photovoltaic energy storage chargers to reduce the impact of electric vehicle charging on the main grid. Currently, mainstream integrated photovoltaic chargers on the market suffer from low energy storage battery utilization efficiency and high photovoltaic power generation costs. These chargers also significantly impact the distribution network load curve, system voltage deviation, increased network losses, system three-phase balance, substation power supply range and short-circuit capacity, and system three-phase balance. Summary of the Invention

[0003] In order to address the deficiencies in the prior art, the present invention provides an on-grid and off-grid photovoltaic energy storage charging system and a charging control method, which can stably charge the powered equipment, avoid interference with the main power grid, and have good economic benefits.

[0004] In order to achieve the above objectives, the present invention adopts a specific solution: a grid-connected and off-grid photovoltaic energy storage and charging system, comprising:

[0005] an energy storage module comprising at least two energy storage devices for storing electrical energy;

[0006] A photovoltaic power generation module, used to convert solar energy into electrical energy and transmit it to the energy storage device;

[0007] A grid-connected or off-grid module, used to control the energy storage module to be connected to or off-grid;

[0008] a charging module, used to transmit the electric energy stored in the energy storage device to the powered device;

[0009] The energy storage management module is used to control the energy storage module, the photovoltaic power generation module and the charging module.

[0010] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage and charging system: the energy storage device includes a plurality of energy storage batteries connected in series and / or in parallel.

[0011] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage and charging system: the photovoltaic power generation module includes an MTTP controller and multiple photovoltaic power generation panels, and the MTTP controller is electrically connected to the energy storage management module.

[0012] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage and charging system: the on-grid and off-grid module includes a bidirectional inverter, the energy storage is connected to the main power grid through the bidirectional inverter, and the bidirectional inverter is electrically connected to the energy storage management module.

[0013] As a further optimization of the above-mentioned off-grid photovoltaic energy storage charging system: the charging module includes a first charging unit and a second charging unit, and the charging power of the first charging unit is greater than the charging power of the second charging unit, and the first charging unit and the second unit are both electrically connected to the energy storage management module.

[0014] A method for controlling on-grid and off-grid photovoltaic energy storage charging is provided, based on the above-mentioned on-grid and off-grid photovoltaic energy storage charging system, and the method comprises the following steps:

[0015] The energy storage management module determines the power demand;

[0016] When there is a demand for electricity, the energy storage management module controls the charging module to transmit the electric energy stored in the energy storage device to the powered device. When there is no demand for electricity, the energy storage management module controls whether to replenish electric energy to the energy storage device according to the storage capacity of the energy storage device.

[0017] When the energy storage device needs to be supplemented with electric energy, the energy storage management module controls the photovoltaic power generation module or the grid-connected and off-grid module to supplement the electric energy for the energy storage device.

[0018] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage charging control method: the specific method in which the energy storage management module controls the charging module to transmit the electric energy stored in the energy storage device to the powered device includes:

[0019] The energy storage management module obtains the storage capacity of all energy storage devices;

[0020] The energy storage management module determines an energy storage device having a storage capacity exceeding a preset first threshold as a candidate energy storage device;

[0021] The energy storage management module sorts the storage capacity of all candidate energy storage devices and selects the candidate energy storage device with the largest storage capacity as the power supply energy storage device;

[0022] The energy storage management module controls the charging module to transmit the electric energy stored in the power supply energy storage device to the powered device.

[0023] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage charging control method: when the storage capacity of all the energy storage devices does not exceed a preset first threshold, the energy storage management module controls the on-grid and off-grid modules to switch the energy storage devices to the grid-connected state, and uses the main power grid to transmit electrical energy to the powered equipment.

[0024] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage charging control method: the specific method of the energy storage management module controlling the photovoltaic power generation module or the on-grid and off-grid module to replenish electric energy for the energy storage device includes:

[0025] The energy storage management module obtains the power generation status of the photovoltaic power generation module and the current electricity price of the main power grid;

[0026] When the power generation state of the photovoltaic power generation module reaches a preset second threshold and the current electricity price exceeds a preset third threshold, the energy storage management module controls the photovoltaic power generation module to replenish electric energy for the energy storage device;

[0027] When the power generation state of the photovoltaic power generation module does not reach the second threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and use the main power grid to supplement the energy storage device with electricity;

[0028] When the current electricity price does not reach the third threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and use the main grid to replenish electricity for the energy storage device.

[0029] As a further optimization of the above-mentioned on-grid and off-grid photovoltaic energy storage charging control method: when there is no electricity demand and there is no need to replenish electric energy to the energy storage device, the energy storage management module controls the on-grid and off-grid module to switch the energy storage device to the grid-connected state, and transmits the electric energy stored in the energy storage device to the main power grid.

[0030] Beneficial effects: The present invention charges the powered device through an energy storage module composed of multiple energy storage devices. The multiple energy storage devices complement each other according to the storage capacity, can stably power the powered device, and achieve the effect of immediate charging without waiting; the photovoltaic power generation module and the main power grid replenish the energy storage device according to the photovoltaic power generation status and the current electricity price. During the charging peak period, the charging pile is powered by energy storage, photovoltaic power generation and city power together to meet the peak power demand, which not only achieves peak shaving and valley filling, but also saves the cost of power distribution and capacity expansion, fully ensures that the energy storage device can supply power stably, and can also input the photovoltaic power generation module into the main power grid, increasing the absorption of new energy, making up for the lack of discontinuity of solar power generation, and achieving maximum economic benefits; it enhances the frequency regulation and peak regulation capabilities of the power grid, reduces the peak-to-valley difference in load, and improves the utilization efficiency of the energy storage device of the photovoltaic energy storage charging pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural block diagram of the charging system of the present invention;

[0032] Figure 2 It is a schematic diagram of the DC busbar of the charging system of the present invention;

[0033] Figure 3 This is a flow chart of the charging control method of the present invention in embodiment 1 when fast charging is performed;

[0034] Figure 4 This is a flow chart of the charging control method of the present invention in the second embodiment when performing slow charging. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments 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 are within the scope of protection of the present invention.

[0036] See also Figure 1 and 2 , a grid-connected and off-grid photovoltaic energy storage and charging system, including an energy storage module, a photovoltaic power generation module, a grid-connected and off-grid module, a charging module and an energy storage management module.

[0037] The energy storage module includes at least two energy storage devices for storing electrical energy.

[0038] Photovoltaic power generation modules are used to convert solar energy into electrical energy and transmit it to energy storage devices.

[0039] The on-grid and off-grid module is used to control the energy storage module to be on-grid or off-grid.

[0040] The charging module is used to transmit the electric energy stored in the energy storage device to the powered device.

[0041] The energy storage management module is used to control the energy storage module, photovoltaic power generation module and charging module.

[0042] During use of the present invention, when a powered device is connected to the system and electric energy needs to be delivered to the powered device, the energy storage management module first selects a suitable energy storage device based on the storage capacity of the energy storage devices in the energy storage module to deliver electric energy to the powered device. All energy storage devices can complement each other, and power delivery to the powered device will not be impossible due to insufficient storage capacity of a single energy storage device, thus avoiding waiting for the user. After determining the energy storage device to deliver electric energy to the powered device, the energy storage management module controls the charging module to deliver the electric energy stored in the energy storage device to the device.

[0043] When the storage capacity of the energy storage device is insufficient to supply power to the power receiving equipment, the photovoltaic power generation module can be used to supplement the energy storage device, or the grid-connected module can be used to switch the energy storage device to the grid-connected state, and the main grid can be used to supplement the energy storage device. The appropriate method of supplementing the energy storage device can be selected according to the current power generation status of the photovoltaic power generation module and the current electricity price of the main grid. Specifically, when the lighting conditions are good during the day, the power generation efficiency of the photovoltaic power generation module is good, and the current electricity price of the main grid is high, the photovoltaic power generation module can be used to supplement the energy storage device, and at night At night, when sunlight conditions are poor, the photovoltaic modules have low efficiency, and the main grid's electricity price is low, the main grid can be used to supplement energy for the energy storage device. During daytime weather conditions, when the photovoltaic modules have low efficiency, and the main grid's electricity price is high, the main grid can be used to supplement energy for the energy storage device to ensure stable overall system operation. When no other method of supplementing energy for the energy storage device can meet its energy storage needs, indicating that the current power receiving device's demand is too strong, the main grid can be used to supply power to the power receiving device.

[0044] When the demand of the power receiving equipment is low, the power generation capacity of the photovoltaic power generation module is large, and the energy storage device is in good energy storage status, the energy storage management module can also be used to control the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and transmit the excess power to the main grid, thereby achieving greater economic benefits.

[0045] The energy storage device is configured as follows: the energy storage device includes multiple energy storage batteries connected in series and / or in parallel. Specifically, each energy storage battery serves as a basic battery unit. Multiple energy storage batteries can be connected in series, in parallel, or combined to form a battery pack. Multiple battery packs are further connected in series to form a battery cluster. Multiple battery clusters are connected in parallel and connected to the same DC busbar, ultimately forming an energy storage device that can meet the required voltage and capacity. Obviously, the more energy storage batteries an energy storage device includes, the greater the total storage capacity of the energy storage device. However, this will correspondingly increase the device size and increase the difficulty of heat dissipation. The appropriate number of energy storage batteries can be selected based on actual needs.

[0046] The specific structure of the photovoltaic power generation module is as follows: the photovoltaic power generation module includes a MTTP controller and multiple photovoltaic panels. The MTTP controller is electrically connected to the energy storage management module. The selection of the MTTP controller and the selection, quantity, and installation of the photovoltaic panels are state-of-the-art technologies in the field and need to be determined based on the actual use case. I will not elaborate on this here.

[0047] Because the energy storage device only needs to switch to a grid-connected state when it needs to draw power from the main grid or transmit power to the main grid, it should remain in an off-grid state under normal conditions to avoid interference between the charging system and the main grid, especially to avoid interference with the main grid. To facilitate switching between the energy storage device's on-grid and off-grid states, the on-grid and off-grid module includes a bidirectional inverter, which connects the energy storage device to the main grid and is electrically connected to the energy storage management module.

[0048] Taking into account that different powered devices have different charging requirements, which are usually mainly reflected in the charging power, in order to meet the needs of powered devices with different charging power, the charging module includes a first charging unit and a second charging unit, and the charging power of the first charging unit is greater than the charging power of the second charging unit. The first charging unit and the second unit are both electrically connected to the energy storage management module.

[0049] A method for controlling on-grid and off-grid photovoltaic energy storage charging is provided, based on the above-mentioned on-grid and off-grid photovoltaic energy storage charging system, and the method includes S1 to S3.

[0050] S1. The energy storage management module determines power demand. Power demand primarily represents the energy demand of powered devices, such as electric vehicles. After a user connects a charging plug to a powered device, the energy storage management module communicates with the powered device using a handshake protocol to determine its power demand. The specific communication process is well-established in the art and will not be detailed here.

[0051] S2. When there is a demand for electricity, the energy storage management module controls the charging module to transfer the energy stored in the energy storage device to the powered device. When there is no demand for electricity, the energy storage management module controls whether to recharge the energy storage device based on the energy storage device's storage capacity. When there is a demand for electricity, it indicates that a powered device is already connected to the charger and needs to be charged. At this time, the energy stored in the energy storage device is transferred to the powered device. The energy stored in the energy storage device is stable, thus stably supplying power to the powered device. When there is no demand for electricity, the control of whether to recharge the energy storage device based on the energy storage device's storage capacity can maintain the energy storage device's storage capacity at a healthy level, thereby stably charging the charging device after the powered device is connected.

[0052] More specifically, the specific method in which the energy storage management module controls the charging module to transmit the electric energy stored in the energy storage device to the powered device includes S211 to S214.

[0053] S211 , the energy storage management module obtains the storage capacity of all energy storage devices.

[0054] S212: The energy storage management module determines an energy storage device with a storage capacity exceeding a preset first threshold as a candidate energy storage device.

[0055] S213 : The energy storage management module sorts the storage capacities of all candidate energy storage devices, and selects the candidate energy storage device with the largest storage capacity as the power supply energy storage device.

[0056] S214: The energy storage management module controls the charging module to transmit the electric energy stored in the power supply energy storage device to the powered device.

[0057] To ensure a more stable supply of power to the powered device, the present invention utilizes multiple energy storage devices to form an energy storage module, with all energy storage devices complementing each other. Energy storage devices with larger storage capacities are preferentially selected as power supply devices to avoid power interruptions caused by insufficient storage capacity. The first threshold can be determined based on actual conditions. In this embodiment, the first threshold is set to 30% of the total storage capacity of the energy storage devices. After the power supply device has completed supplying power to the powered device, it is again determined whether its storage capacity exceeds the first threshold. If so, the power supply device will continue to supply power when a subsequent powered device is connected. Otherwise, the second candidate energy storage device is selected from all candidate energy storage devices in order as the new power supply device. This avoids the need to repeatedly screen power supply devices each time a powered device is connected, thus shortening waiting time. After all candidate energy storage devices have served as power supply devices to the powered device, S211 is re-executed the next time a powered device is connected.

[0058] In some special cases, the storage capacity of all energy storage devices may not be enough to supply power to the powered device. In order to ensure that stable charging service can still be provided, when the storage capacity of all energy storage devices does not exceed a preset first threshold, the energy storage management module controls the grid-connected module to switch the energy storage devices to the grid-connected state and use the main power grid to transmit power to the powered device.

[0059] In addition, different powered devices have different requirements for charging power, and can be divided into two categories: fast charging and slow charging according to the size of the charging power. The corresponding first charging unit is used to achieve fast charging, and the second charging unit is used to achieve slow charging. When the powered device is fast charged using the energy storage device or the main power grid, the first charging unit directly transmits the power of the energy storage device to the powered device; when the powered device is slow charged using the energy storage device or the main power grid, the second charging unit includes a DC conversion module and an AC conversion module, which are respectively used to convert the power of the energy storage device and the power of the main power grid. The AC conversion module can use an AC / DC bidirectional converter, and the DC conversion module can use a DC / DC bidirectional converter.

[0060] S3. When the energy storage device needs to be supplemented with electric energy, the energy storage management module controls the photovoltaic power generation module or the grid-connected or off-grid module to supplement the electric energy storage device.

[0061] Specifically, the specific method of the energy storage management module controlling the photovoltaic power generation module or the grid-connected or off-grid module to supplement electric energy for the energy storage device includes S31 to S34.

[0062] S31. The energy storage management module obtains the power generation status of the photovoltaic power generation module and the current electricity price of the main power grid.

[0063] S32: When the power generation state of the photovoltaic power generation module reaches a preset second threshold and the current electricity price exceeds a preset third threshold, the energy storage management module controls the photovoltaic power generation module to replenish electric energy for the energy storage device.

[0064] S33. When the power generation state of the photovoltaic power generation module does not reach the second threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and uses the main power grid to supplement power for the energy storage device.

[0065] S34. When the current electricity price does not reach the third threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and use the main grid to replenish power for the energy storage device.

[0066] Because the power generation status of the photovoltaic power generation module changes with the weather and is not stable, it is necessary to first obtain the power generation status of the photovoltaic power generation module to determine whether the energy storage device can be replenished with electricity, so as to avoid the situation where the photovoltaic power generation module cannot be smoothly replenished with electricity to the energy storage device even if the photovoltaic power generation module is connected to the energy storage device. On the other hand, in areas with tiered electricity prices, because the demand for electricity is high during the day, the electricity price is also higher, while the demand for electricity is low at night, the electricity price is also lower. When the electricity price is low, using the main power grid to replenish electricity to the energy storage device is also a method to ensure the stable operation of the charging system. The present invention combines these two factors and preferentially uses the photovoltaic power generation module to replenish electricity to the energy storage device to achieve the lowest cost. Secondly, when the current electricity price is low, the main power grid is used to replenish electricity to the energy storage device. In the worst case, that is, when the power generation status of the photovoltaic power generation module is poor and the current electricity price is high, in order to ensure the stable operation of the charging system, the main power grid can also be used to replenish electricity to the energy storage device.

[0067] It should also be noted that when the storage capacity of all energy storage devices cannot meet the charging demand, the charging equipment needs to be powered by the main power grid. At this time, the main power grid first transmits electricity to the energy storage device, and then provides electricity to the receiving device through the energy storage device. The excess electricity is replenished to the energy storage device, and the energy storage device is replenished with electricity while charging the receiving device, achieving higher operating efficiency.

[0068] In order to achieve greater economic benefits, when there is no electricity demand and no need to replenish electricity to the energy storage device, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state and transmit the electricity stored in the energy storage device to the main power grid.

[0069] The following two specific embodiments provide a detailed explanation of the charging control method of the present invention. In both embodiments, the energy storage module includes two energy storage devices, each of which is composed of a group of energy storage batteries, described as Group A and Group B. Specifically, the first energy storage device is described as Group A, and the second energy storage device is described as Group B. The first threshold is set to 30%.

[0070] Example 1.

[0071] See also Figure 3 When the powered device is an electric vehicle and requires fast charging, after the user connects the fast charging plug, the energy storage management module detects the charging needs of the electric vehicle, and then determines whether the storage capacity of group A energy storage batteries has reached 30%. If so, group A energy storage batteries are used to charge the electric vehicle, and the electricity generated by the photovoltaic power generation module is transmitted to group B energy storage batteries for charging. Otherwise, it is determined whether the storage capacity of group B energy storage batteries has reached 30%. If so, group B energy storage batteries are used to charge the electric vehicle, and the electricity generated by the photovoltaic power generation module is transmitted to group A energy storage batteries for charging. Otherwise, the main power grid is connected to charge the electric vehicle, and the electricity generated by the photovoltaic power generation module is transmitted to group A energy storage batteries for charging. After the storage capacity of group A energy storage batteries reaches 90%, group B energy storage batteries are charged.

[0072] Example 2.

[0073] See also Figure 4 When the powered device is an electric vehicle and slow charging is required, after the user connects the slow charging plug, the energy storage management module detects the charging demand of the electric vehicle, and then determines whether the storage capacity of group A energy storage battery reaches 30%. If so, group A energy storage battery is used to charge the electric vehicle through the DC conversion module, and the electric energy generated by the photovoltaic power generation module is transmitted to group B energy storage battery for charging. Otherwise, it is determined whether the storage capacity of group B energy storage battery reaches 30%. If so, group B energy storage battery is used to charge the electric vehicle through the DC conversion module, and the electric energy generated by the photovoltaic power generation module is transmitted to group A energy storage battery for charging. Otherwise, it is connected to the main power grid to charge the electric vehicle through the AC conversion module, and the electric energy generated by the photovoltaic power generation module is transmitted to group A energy storage battery for charging. After the storage capacity of group A energy storage battery reaches 90%, group B energy storage battery is charged.

[0074] Finally, it should be noted that the present invention is applicable to any powered device that has a large demand for charging power, and is not limited to the electric vehicles described in the above embodiments. The above embodiments only use electric vehicles as examples to clearly illustrate the technical solutions of the present invention.

[0075] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling on-grid and off-grid photovoltaic energy storage charging, based on an on-grid and off-grid photovoltaic energy storage charging system, wherein the system comprises an energy storage module, including at least two energy storage devices for storing electrical energy; a photovoltaic power generation module for converting solar energy into electrical energy and transmitting the energy to the energy storage devices; An on-grid and off-grid module for controlling the energy storage module to be on-grid or off-grid; a charging module for transmitting the electric energy stored in the energy storage device to the powered device; an energy storage management module for controlling the energy storage module, the photovoltaic power generation module, and the charging module, wherein the control methods include selecting an energy storage device to transmit electric energy to the powered device based on the storage capacity of the energy storage device in the energy storage module, controlling the photovoltaic power generation module to replenish electric energy to the energy storage device, controlling the on-grid and off-grid module to switch the energy storage device to a grid-connected state to utilize the main grid to replenish electric energy to the energy storage device, controlling the on-grid and off-grid module to utilize the main grid to transmit electric energy to the powered device, and controlling the on-grid and off-grid module to switch the energy storage device to a grid-connected state to transmit electric energy to the main grid; It is characterized by: The method comprises the following steps: The energy storage management module determines the power demand; When there is a demand for electricity, the energy storage management module controls the charging module to transmit the electric energy stored in the energy storage device to the powered device. When there is no demand for electricity, the energy storage management module controls whether to replenish electric energy to the energy storage device according to the storage capacity of the energy storage device. The specific method of the energy storage management module controlling the charging module to transmit the electric energy stored in the energy storage device to the powered device includes: The energy storage management module obtains the storage capacity of all energy storage devices; The energy storage management module determines an energy storage device having a storage capacity exceeding a preset first threshold as a candidate energy storage device; The energy storage management module sorts the storage capacity of all candidate energy storage devices and selects the candidate energy storage device with the largest storage capacity as the power supply energy storage device; The energy storage management module controls the charging module to transmit the electric energy stored in the power supply energy storage device to the powered device; After the power supply energy storage device has finished supplying power to the powered device, it is determined again whether its storage capacity exceeds the first threshold. If so, the power supply energy storage device will continue to supply power when a powered device is subsequently connected. Otherwise, the second candidate energy storage device is selected from all candidate energy storage devices in order as the new power supply energy storage device. If the storage capacity of the energy storage device does not reach the first threshold, replenishing electric energy to the energy storage device until the storage capacity reaches 90%; When the energy storage device needs to be supplemented with electric energy, the energy storage management module controls the photovoltaic power generation module or the grid-connected and off-grid module to supplement the energy storage device with electric energy; When the storage capacity of all energy storage devices does not exceed the preset first threshold and cannot supply power to the powered device, the energy storage management module controls the grid-connected module to switch the energy storage device to the grid-connected state and use the main power grid to transmit power to the powered device.

2. A method for controlling charging of an on-grid and off-grid photovoltaic energy storage system according to claim 1, characterized in that: When the storage capacity of all the energy storage devices does not exceed a preset first threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to a grid-connected state, and transmits electric energy to the powered device using the main grid.

3. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: The specific method of the energy storage management module controlling the photovoltaic power generation module or the grid-connected and off-grid module to supplement the energy storage device with electric energy includes: The energy storage management module obtains the power generation status of the photovoltaic power generation module and the current electricity price of the main power grid; When the power generation state of the photovoltaic power generation module reaches a preset second threshold and the current electricity price exceeds a preset third threshold, the energy storage management module controls the photovoltaic power generation module to replenish electric energy for the energy storage device; When the power generation state of the photovoltaic power generation module does not reach the second threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and use the main power grid to supplement the energy storage device with electricity; When the current electricity price does not reach the third threshold, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state, and use the main grid to replenish electricity for the energy storage device.

4. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: When there is no electricity demand and the energy storage device does not need to be replenished with electric energy, the energy storage management module controls the grid-connected and off-grid module to switch the energy storage device to the grid-connected state and transmit the electric energy stored in the energy storage device to the main grid.

5. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: The energy storage device includes a plurality of energy storage batteries connected in series and / or in parallel.

6. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: The photovoltaic power generation module includes a MTTP controller and a plurality of photovoltaic power generation panels, and the MTTP controller is electrically connected to the energy storage management module.

7. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: The on-grid and off-grid module includes a bidirectional inverter, the energy storage device is connected to the main power grid through the bidirectional inverter, and the bidirectional inverter is electrically connected to the energy storage management module.

8. The on-grid and off-grid photovoltaic energy storage charging control method according to claim 1, characterized in that: The charging module includes a first charging unit and a second charging unit, and the charging power of the first charging unit is greater than the charging power of the second charging unit. The first charging unit and the second unit are both electrically connected to the energy storage management module.

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