A photovoltaic, energy storage, reverse current prevention energy management and control device

Abstract

The utility model discloses a kind of photovoltaic, energy storage anti-backflow energy management and control device, it is related to new energy energy management and control technical field, including local load is connected with power grid through first switch and second switch, through the intelligent electric meter and CT sampler in series in power grid connection point, the intelligent electric meter is connected with power grid through second switch, it is characterized in that;The anti-backflow energy management controller and photovoltaic energy storage station;The electric quantity monitoring module includes bidirectional intelligent electric meter and CT sampler;Intelligent electric meter: it is used to obtain grid active power ρ grid under power grid and load total power ρ load in real time;The utility model opens or closes photovoltaic inverter and energy storage converter in turn according to the size of real-time load, cooperates the instruction response of anti-backflow energy management controller, prevents photovoltaic and energy storage electric energy backflow into power grid, guarantees power grid safety and stability, improves the energy utilization of light storage system.

Description

Technical Field

[0001] This utility model relates to the field of new energy energy management and control technology, specifically a photovoltaic and energy storage anti-backflow energy management and control device. Background Technology

[0002] With the rapid development of new energy power generation technologies, especially the increasing maturity of photovoltaic power generation technology, the government has adopted an encouraging and cooperative policy attitude towards photovoltaic power generation and energy storage. However, the grid-connected operation of photovoltaic and energy storage systems can easily lead to reverse power transmission (reverse flow), resulting in grid voltage exceeding limits, protection malfunctions, and metering disputes.

[0003] Traditional anti-reverse current schemes mainly use single power limiting (such as setting a fixed threshold to force power reduction) or hard disconnection (directly disconnecting the grid-connected line through a mechanical switch). The working principle is to detect reverse current through a current transformer. When it exceeds the preset value, either the inverter is instructed to reduce the load to below 50%, or the contactor is triggered to physically cut off the circuit.

[0004] Traditional anti-backflow solutions suffer from significant drawbacks, including slow response (requiring 300ms-5 minutes due to low-speed sampling and mechanical actions), low equipment utilization (frequent start-stop cycles result in actual utilization rates of less than 60% for photovoltaic / energy storage equipment), and coarse control (unable to dynamically adjust the coordination of multiple devices). These limitations make them ill-suited for the rapid and accurate anti-backflow requirements of scenarios with high proportions of renewable energy integration. Therefore, we propose a photovoltaic and energy storage anti-backflow energy management and control device. Utility Model Content

[0005] To address the shortcomings of existing technologies, this utility model provides a photovoltaic energy storage anti-reverse current device with hierarchical start-stop control. By using a sequential control strategy to balance power generation and load, it achieves zero reverse current and optimized equipment lifespan.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a photovoltaic and energy storage anti-reverse current energy management and control device, comprising a local load connected to the power grid via a first switch and a second switch, and a smart meter and a CT sampler connected in series at the power grid connection point. The smart meter is connected to the power grid via the second switch. The device also includes an anti-reverse current energy management controller and a photovoltaic energy storage station. The power monitoring module includes a bidirectional smart meter and a CT sampler. The smart meter is used to acquire the active power ρ_grid and the total load power ρ_load in real time. The CT sampler detects the current direction on the grid side in real time to verify the reverse current status.

[0007] The local load is a collection of electrical devices connected in the power supply circuit of the photovoltaic energy storage system;

[0008] The photovoltaic energy storage station includes a photovoltaic inverter group and an energy storage converter group. The photovoltaic inverter group includes several photovoltaic inverters and several PV photovoltaic arrays. The input terminals of several photovoltaic inverters are connected to the PV photovoltaic arrays, and the output terminals of several photovoltaic inverters are connected to the AC bus through a third switch.

[0009] The communication interface connects to the photovoltaic inverter group, energy storage converter group and smart meter via RS485 bus.

[0010] The anti-reverse current energy management controller is used to monitor the amount of electricity discharged from the power grid in real time; the anti-reverse current energy management controller monitors the voltage and current values ​​and directions of the power grid connection point in real time through the communication interface, and dynamically calculates the amount of electricity discharged from the power grid.

[0011] The anti-backflow energy management controller is communicatively connected to a smart meter, a photovoltaic inverter group, and an energy storage converter group.

[0012] The energy storage converter group includes several bidirectional converters and energy storage battery packs. The DC terminals of several bidirectional converters are connected to the energy storage battery packs, and the AC terminals of several bidirectional converters are connected to an AC bus via a fourth switch.

[0013] Among them, the anti-reverse current energy management controller performs the following operations according to the change of the grid-connected power: when the grid-connected power is >0, the photovoltaic inverter (1~N) and the energy storage converter (1~N) are started.

[0014] When the grid-connected power supply is close to or equal to 0, shut down the energy storage converter (1~N) and the photovoltaic inverter (1~N).

[0015] According to the above technical solution, the anti-reverse flow energy management controller prioritizes starting the photovoltaic inverter group, and then starts the energy storage converter group; it prioritizes shutting down the energy storage converter group, and then shuts down the photovoltaic inverter group, so as to maximize the economic benefits of photovoltaic power generation.

[0016] According to the above technical solution, the startup sequence of the photovoltaic inverters (1~N) is as follows: when the grid power supply continues to increase, the inverters are started one by one in numerical order; when the grid power supply continues to decrease, the inverters are shut down one by one in reverse numerical order.

[0017] According to the above technical solution, the startup sequence of the energy storage converters (1~N) is as follows: the converters are started in numerical order only when there is still a demand for grid-connected electricity after all photovoltaic inverters have started; when the grid-connected electricity is close to 0, all converters are shut down in numerical order first.

[0018] This invention provides a photovoltaic and energy storage anti-backflow energy management and control device. It has the following beneficial effects:

[0019] 1. This utility model sequentially turns on or off the photovoltaic inverter and energy storage converter according to the real-time load size, and cooperates with the command response of the anti-backflow energy management controller to prevent photovoltaic and energy storage power from flowing back into the grid, thus ensuring the safety and stability of the grid and improving the energy utilization rate of the photovoltaic-storage system.

[0020] 2. This utility model maximizes the revenue from photovoltaic power generation by dynamically scheduling photovoltaic and energy storage resources based on economic priorities. Since the economic benefits of photovoltaic power generation are greater than those of energy storage discharge, it prioritizes the activation of photovoltaic inverters for power generation or the shutdown of energy storage converters for discharge to improve the economic benefits of the photovoltaic energy storage station. It also avoids the long-term operation of all equipment and extends the service life of the equipment. Attached Figure Description

[0021] Figure 1 A schematic diagram of the composition of a photovoltaic, energy storage, anti-backflow energy management and control device provided by this utility model. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1 One embodiment of this utility model is: a photovoltaic and energy storage anti-reverse current energy management and control device, comprising a local load connected to the power grid via a first switch and a second switch, and a smart meter and a CT sampler connected in series at the power grid connection point. The smart meter is connected to the power grid via the second switch. The device also includes an anti-reverse current energy management controller and a photovoltaic energy storage station. The power monitoring module includes a bidirectional smart meter and a CT sampler. The smart meter is used to acquire the active power ρ_grid and the total load power ρ_load in real time. The CT sampler detects the current direction on the grid side in real time to verify the reverse current status.

[0024] The local load is a collection of electrical devices connected in the power supply circuit of the photovoltaic energy storage system;

[0025] The anti-backflow energy management controller is communicatively connected to a smart meter and a photovoltaic energy storage station.

[0026] The photovoltaic energy storage power station includes a photovoltaic inverter group and an energy storage converter group. The photovoltaic inverter group includes several photovoltaic inverters and several PV photovoltaic arrays. The input terminals of several photovoltaic inverters are connected to the PV photovoltaic arrays, and the output terminals of several photovoltaic inverters are connected to the AC bus through a third switch. The energy storage converter group includes several bidirectional converters and energy storage battery packs. The DC terminals of several bidirectional converters are connected to the energy storage battery packs, and the AC terminals of several bidirectional converters are connected to the AC bus through a fourth switch.

[0027] The communication interface connects to the photovoltaic inverter group, energy storage converter group and smart meter via RS485 bus.

[0028] The anti-reverse current energy management controller is used to monitor the amount of electricity discharged from the power grid in real time; the anti-reverse current energy management controller monitors the voltage and current values ​​and directions of the power grid connection point in real time through the communication interface, and dynamically calculates the amount of electricity discharged from the power grid.

[0029] Among them, the anti-reverse current energy management controller performs the following operations according to the change of the grid-connected power: when the grid-connected power is >0, the photovoltaic inverter (1~N) and the energy storage converter (1~N) are started.

[0030] When the grid-connected power supply is close to or equal to 0, shut down the energy storage converter (1~N) and the photovoltaic inverter (1~N).

[0031] The anti-reverse flow energy management controller prioritizes starting the photovoltaic inverter group, followed by starting the energy storage converter group; it prioritizes shutting down the energy storage converter group, followed by shutting down the photovoltaic inverter group, in order to maximize the economic benefits of photovoltaic power generation.

[0032] The startup sequence of the photovoltaic inverters (1~N) is as follows: when the grid power supply continues to increase, the inverters are started one by one in numerical order; when the grid power supply continues to decrease, the inverters are shut down one by one in reverse numerical order.

[0033] The startup sequence of the energy storage converters (1~N) is as follows: the converters are started in numerical order only when there is still a demand for grid-connected electricity after all photovoltaic inverters have started; when the grid-connected electricity is close to 0, all converters are shut down in numerical order first.

[0034] In this embodiment, when a photovoltaic and energy storage anti-reverse flow energy management and control device is in operation, the local load has a power demand and draws power from the AC bus. If the PV photovoltaic array and energy storage battery pack are not started or are only partially running, the local power generation is insufficient to meet the load demand. The grid supplies power to the system through switches (first switch and second switch), resulting in the power output from the grid being > 0 (i.e., the grid sends power to the local load).

[0035] PV photovoltaic arrays convert solar energy into direct current (DC). Energy storage battery banks store excess photovoltaic energy or off-peak grid energy, and then regulate charging and discharging through chemical energy conversion into electrical energy. When sunlight conditions permit, the PV array generates DC. This DC is input to a photovoltaic inverter (e.g., inverters 1-N), which converts DC to alternating current (AC) and outputs it to the AC bus (via a third switch). When photovoltaic power generation is insufficient or for economic reasons, the energy storage battery banks (via energy storage converters (1-N)) discharge: the energy storage converters (1-N) convert the battery's DC to AC and output it to the AC bus (via a third switch). The energy storage system can also be charged during off-peak grid periods. Local loads directly draw AC power from the AC bus without additional conversion. Therefore, if the total local power generation (PV + energy storage) exceeds the load demand and is not controlled, excess power may flow back to the grid. The anti-backflow energy management controller prevents this.

[0036] The smart meter and CT sampler are connected in series at the grid connection point to monitor the voltage and current values ​​and directions at the grid connection point in real time (positive values ​​indicate grid power supply, negative values ​​indicate reverse current). These digital signals are sent to the anti-reverse current energy management controller via an RS485 communication bus. The anti-reverse current energy management controller dynamically calculates the amount of electricity discharged from the grid as a basis for decision-making.

[0037] When the off-grid power is > 0, the anti-reverse current energy management controller issues a command, and the photovoltaic energy storage station starts generating electricity (high load demand, insufficient local power generation): the anti-reverse current energy management controller first starts the photovoltaic inverter group, and starts the photovoltaic inverters one by one in the order of number (1~N); if the off-grid power is still > 0 after all photovoltaic inverters have started, the anti-reverse current energy management controller then starts the energy storage converter group, and starts the energy storage converters one by one in the order of number (1~N) to discharge.

[0038] When the off-grid electricity is close to or equal to 0 (low load demand, local power generation may be excessive), the anti-reverse flow energy management controller issues a command to stop the photovoltaic storage station from generating electricity to avoid reverse power transmission between photovoltaic and storage. The anti-reverse flow energy management controller prioritizes shutting down the energy storage converter group, shutting down the energy storage converter one by one in the order of number (1~N). If the off-grid electricity is still close to 0, the controller then shuts down the photovoltaic inverter group: shutting down the photovoltaic inverter one by one in the reverse order of number (N~1).

[0039] When local power generation equals load demand, the grid-connected power is 0, and the grid neither supplies nor receives power. When local power generation is less than load demand, the grid-connected power is greater than 0, and the grid supplements power supply. When local power generation exceeds load demand, the anti-backflow energy management controller issues an instruction to quickly reduce the operation of power generation equipment to ensure no backflow.

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic and energy storage anti-reverse current energy management and control device, comprising a local load connected to the power grid via a first switch and a second switch, and a smart meter and a CT sampler connected in series at the power grid connection point, wherein the smart meter is connected to the power grid via the second switch, characterized in that; Anti-reverse current energy management controller and photovoltaic energy storage station; power monitoring module includes bidirectional smart meter and CT sampler; smart meter: it is used to obtain the active power ρ grid and the total load power ρ load in real time; CT sampler: it detects the current direction on the grid side in real time to verify the reverse current status; The local load is a collection of electrical devices connected in the power supply circuit of the photovoltaic energy storage system; The anti-backflow energy management controller is communicatively connected to a smart meter and a photovoltaic energy storage station. The photovoltaic energy storage power station includes a photovoltaic inverter group and an energy storage converter group. The photovoltaic inverter group includes several photovoltaic inverters and several PV photovoltaic arrays. The input terminals of several photovoltaic inverters are connected to the PV photovoltaic arrays, and the output terminals of several photovoltaic inverters are connected to the AC bus through a third switch. The energy storage converter group includes several bidirectional converters and energy storage battery packs. The DC terminals of several bidirectional converters are connected to the energy storage battery packs, and the AC terminals of several bidirectional converters are connected to the AC bus through a fourth switch. The communication interface connects to the photovoltaic inverter group, energy storage converter group and smart meter via RS485 bus. The anti-reverse current energy management controller is used to monitor the amount of electricity discharged from the power grid in real time. The anti-reverse current energy management controller monitors the voltage and current values ​​and directions of the power grid connection point in real time through the communication interface, and dynamically calculates the amount of electricity discharged from the power grid.

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