WO2023130488A1

WO2023130488A1 - Self-sustained power generation method and terminal under micro electric quantity of photovoltaic energy storage off-grid system

Info

Publication number: WO2023130488A1
Application number: PCT/CN2022/071543
Authority: WO
Inventors: 石正平; 许清荣
Original assignee: 福建时代星云科技有限公司
Priority date: 2022-01-06
Filing date: 2022-01-12
Publication date: 2023-07-13
Also published as: CN114400672A

Abstract

A self-sustained power generation method and terminal under a micro electric quantity of a photovoltaic energy storage off-grid system. The method comprises the steps of: acquiring, in real time, an electric quantity value of a battery energy storage unit in a photovoltaic energy storage off-grid system (S1); and according to a threshold value range within which the electric quantity value is located, sequentially controlling the turning-on and turning-off of an external load contactor and an internal load contactor in the photovoltaic energy storage off-grid system, wherein the external load contactor is connected to an external electric load, the internal load contactor is connected to an internal electric load of the photovoltaic energy storage off-grid system, and the minimum value of the threshold value range is the electric quantity that the battery energy storage unit can support to start a photovoltaic power generation unit once (S2). In the method, by means of sequentially controlling the turning-on and turning-off of power supply of the external electric load and the internal electric load, self-sustained power generation can be cut off in a timely manner when an electric quantity value of the battery energy storage unit is consumed to the minimum value, such that the residual electric quantity is reserved for the battery energy storage unit to support the subsequent self-starting of the photovoltaic energy storage off-grid system, thereby ensuring the intelligent, safe, stable and reliable operation of the photovoltaic energy storage off-grid system.

Description

Self-protection method and terminal of a light-storage off-grid system under micro-power conditions

technical field

The invention relates to the technical field of optical storage off-grid systems, in particular to a self-protection method and terminal for the optical storage off-grid system under low power conditions.

Background technique

At present, human society is facing the problems of climate warming, shortage of non-renewable energy and environmental degradation. In response to this situation, countries around the world are committed to promoting the rapid development of new energy and energy storage.

With the rapid development and popularization of energy storage systems, the optical storage micro-grid (off-grid) system is gradually promoted on islands or areas where electricity is difficult to use. The energy storage battery outputs a stable micro-grid voltage source through the energy storage converter. , relying on the green and environmentally friendly photovoltaic energy to be incorporated into the micro-grid voltage source to supply power for the load and energy storage battery.

However, due to the instability of photovoltaic power generation in the existing design scheme of photovoltaic storage off-grid system, in extreme weather, photovoltaic power generation cannot be generated for a long time, resulting in the exhaustion of energy storage battery system, and the uninterruptible power supply (UPS) has its own battery power When there is no mains power supply or external power generation equipment (such as diesel generators, etc.), the system cannot be restarted, which seriously affects the reliability of the system, not only reduces the continuous running time of the system, but also brings extremely poor The sense of experience will lead to huge losses in manpower, material and financial resources due to after-sales maintenance.

Therefore, how to provide an intelligent identification and control system for self-protection under the low power of the optical storage off-grid system, so as to ensure that the system can be restarted quickly and conveniently, has become an urgent problem to be solved.

technical problem

The technical problem to be solved by the present invention is: to provide a self-protection power method and terminal of the off-grid optical storage system under low power, so as to ensure that the off-grid optical storage system can enter the self-protection power-off state in time under low power, so as to save power for the next time. Reserved power for self-starting.

technical solution

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A method for self-maintaining electricity in a light-storage off-grid system under micro-power conditions, comprising the steps of:

S1. Obtain the power value of the battery energy storage unit in the optical storage off-grid system in real time;

S2. According to the threshold range where the electricity value is located, control the sequential on-off of the external load contactor and the internal load contactor in the optical-storage off-grid system, the external load contactor is connected to the external electrical load, and the internal load contactor The load contactor is connected to the internal power load of the photovoltaic storage off-grid system, and the minimum value of the threshold range is the amount of electricity that the battery energy storage unit can support to start the photovoltaic power generation unit once.

In order to solve the above technical problems, another technical solution provided by the present invention is:

A self-sustaining power terminal under the micro-power of the optical storage off-grid system, the terminal is an energy management unit, and the energy management unit includes a memory, a processor, and a computer program stored on the memory and operable on the processor, When the processor executes the computer program, the following steps are implemented:

Beneficial effect

The beneficial effect of the present invention is that: the present invention provides a method and terminal for self-maintaining power under low power of the optical storage off-grid system, by obtaining the power value of the battery energy storage unit in real time, and controlling the external The on-off of the load contactor and the internal load contactor, so that when the power of the battery energy storage unit is low, it is disconnected to supply power to the external power load, and when the power value is consumed to a minimum value, it is then disconnected to supply power to the internal power load. Power supply, enter the self-maintenance shutdown state, in order to reserve the remaining power for the battery energy storage unit to support the subsequent self-start of the optical storage off-grid system, and ensure the intelligent, safe, stable and reliable operation of the optical storage off-grid system.

Description of drawings

Fig. 1 is a main flow chart of a method for self-maintaining electricity in a light-storage off-grid system in an embodiment of the present invention under a micro-power condition

Fig. 2 is a schematic block diagram of a main circuit of an optical storage off-grid system according to an embodiment of the present invention;

Fig. 3 is a communication principle block diagram of an optical storage off-grid system according to an embodiment of the present invention;

Fig. 4 is a schematic block diagram of power supply of an uninterruptible power supply in an optical storage off-grid system according to an embodiment of the present invention;

Fig. 5 is a specific flow chart of a method for self-maintaining electricity in a light-storage off-grid system in an embodiment of the present invention;

Fig. 6 is a schematic structural diagram of a self-protection power terminal of an optical-storage off-grid system in an embodiment of the present invention under a micro-power condition.

Label description:

1. A self-guaranteed power terminal for an optical storage off-grid system with low power; 2. Memory; 3. Processor.

Embodiments of the present invention

In order to describe the technical content, achieved goals and effects of the present invention in detail, the following descriptions will be made in conjunction with the embodiments and accompanying drawings.

Please refer to Figure 1 to Figure 5, a method for self-maintaining power in a light-storage off-grid system under low power conditions, including steps:

It can be seen from the above description that the beneficial effect of the present invention lies in: by acquiring the power value of the battery energy storage unit in real time, and sequentially controlling the on-off of the external load contactor and the internal load contactor according to the threshold range of the power value, so that the battery storage unit When the power of the energy unit is low, it will be disconnected to supply power to the external power load. When the power value reaches the minimum value, it will be disconnected to supply power to the internal power load, and enter the self-protection power shutdown state, so as to reserve power for the battery energy storage unit. Reserve the remaining power to support the subsequent self-start of the optical-storage off-grid system to ensure the intelligent, safe, stable and reliable operation of the optical-storage off-grid system.

Further, the external load contactor includes a main load contactor and a secondary load contactor, and the external power load is selected to be connected to the main load contactor or the secondary load contactor according to power consumption requirements;

Described step S2 specifically comprises:

S21. When the power value is greater than 30% of the storage capacity of the battery energy storage unit, control the battery energy storage unit to continue supplying power to the external electric load and the internal electric load;

S22. When the power value is 20% to 30% of the storage capacity, control the secondary load contactor to disconnect, and cut off the battery energy storage unit as the secondary load contactor. The power supply of the external electric load, only supplies power to the external electric load and the internal electric load connected to the main load contactor;

S23. When the power value is 10% to 20% of the storage capacity, control the main load contactor to disconnect, and cut off the battery energy storage unit as the external power supply connected to the main load contactor. The power supply of the electric load, only supplies power to the internal electric load;

S24. When the power value is less than 10% of the storage capacity, control the internal load contactor to disconnect, cut off the power supply of the battery energy storage unit to the internal electric load, and the optical storage off-grid system Shut down and enter the self-protection power sleep state.

From the above description, it can be seen that by classifying the external load contactors and adding the main and secondary load contactors, the external electric loads are also divided into main and secondary. With the setting of the threshold range, as the power stored in the battery energy storage unit decreases, the power supply of the external secondary power load, the external main power load and the internal power load will be disconnected sequentially, and the power supply of the external main power load and the internal power load will be disconnected in order to ensure that enough power is reserved in the end before entering the automatic power supply. While maintaining the power state, it also prolongs the duration of the system in self-consumption mode to a certain extent, improving the reliability and stability of the continuous operation of the system.

Further, before the step S1, it also includes:

S01. Control the photovoltaic power generation unit of the solar-storage off-grid system to supply power to the external power load and the internal power load in a sunny environment, and charge the battery energy storage unit;

S02. When the photovoltaic power generation unit is not working, control the inverter output of the battery energy storage unit to supply power for the external electric load and the internal electric load.

From the above description, it can be known that photovoltaic power generation is used to supply power for external loads and the internal loads of the off-grid solar storage system in sunny environments. Inverter discharge supplies power to external and internal electrical loads to ensure the normal operation of the optical-storage off-grid system and the normal power consumption of users.

Further, the optical storage off-grid system also includes an uninterruptible power supply, the uninterruptible power supply is charged by the photovoltaic power generation unit or the battery energy storage unit, and the uninterruptible power supply is the power supply of the optical storage off-grid system Power supply for back-end precision instruments and equipment.

From the above description, it can be seen that the uninterruptible power supply equipment has its own internal battery, which can be charged by the photovoltaic power generation unit or battery energy storage unit of the optical storage off-grid system, and at the same time, the reversible output stable AC voltage supplies power for the back-end precision equipment. For example, the energy management unit of the optical storage off-grid system, the battery management unit, the control coil of the load contactor and the electric energy meter, etc.

Further, after the step S2, it also includes:

S31. In a sunny environment, control the internal load contactor to be closed under the power supply of the uninterruptible power supply, and start the battery energy storage unit;

S32. The battery energy storage unit inverts and outputs the remaining power to the photovoltaic power generation unit, and starts the photovoltaic power generation unit;

S33. The photovoltaic power generation unit charges the battery energy storage unit and the uninterruptible power supply through photovoltaic power generation, supplies power for the internal electric load and the external electric load, and the optical storage off-grid system completes the automatic start up.

From the above description, it can be seen that the self-starting of the optical storage off-grid system is carried out in a sunny environment, that is, under the condition of sufficient light, and the uninterruptible power supply provides a one-button start condition. After the power supply is turned on, the coil of the internal load contactor can be controlled to pull in, so that the internal power load is turned on sequentially by the power of the battery energy storage unit, and finally enters the state of photovoltaic power generation to restore the normal operation of the system.

Please refer to Fig. 6, a kind of self-protection power terminal under the low power of the optical storage off-grid system, the terminal is an energy management unit, and the energy management unit includes a memory, a processor, and is stored on the memory and can be stored on the processor A running computer program, the processor implements the following steps when executing the computer program:

It can be seen from the above description that the beneficial effect of the present invention is that: based on the same technical concept, in conjunction with the above-mentioned method for self-protection under low power of the optical storage off-grid system, a self-protection method under low power of the optical storage off-grid system is provided. Electric terminal, by obtaining the power value of the battery energy storage unit in real time, and sequentially controlling the on-off of the external load contactor and the internal load contactor according to the threshold range of the power value, so as to disconnect when the power of the battery energy storage unit is low Supply power to external loads. When the power value reaches the minimum value, then disconnect the power supply for internal loads and enter the self-protection power shutdown state, so as to reserve the remaining power for the battery energy storage unit to support optical storage and isolation. The subsequent self-start of the grid system ensures the intelligent, safe, stable and reliable operation of the optical storage off-grid system.

Described step S2 specifically comprises:

Further, before the step S1, it also includes:

Further, after the step S2, it also includes:

The present invention is used in the scene where the off-grid optical storage system is controlled by self-protection power-off and the control system is automatically restarted after the power-off, and will be described in conjunction with specific embodiments below.

Please refer to Fig. 1 to Fig. 5, embodiment one of the present invention is:

A method for self-maintaining electricity in a light-storage off-grid system with a small amount of power. First, as shown in FIG. The power generation unit, the battery energy storage unit and the AC power distribution unit are connected to the external electric load through the same AC bus, and the external electric load can be supplied with electricity by the photovoltaic power generation unit and the battery energy storage unit. Among them, in this embodiment, the photovoltaic power generation unit is composed of a photovoltaic inverter and a photovoltaic module, and the battery energy storage unit includes an energy storage converter PCS and an energy storage battery. On the one hand, the AC power distribution unit can be used to control the photovoltaic power generation unit, The battery energy storage unit and the external electric load distribute power. On the other hand, it also includes an external load contactor connected to the external electric load, an internal load contactor connected to the internal electric load, and an external load contactor for obtaining the external electric load. The energy meter of the electric power consumption of the electric load. At the same time, the optical storage off-grid system also includes the energy management unit EMS not marked on the diagram and other internal electric equipment such as energy storage converters and photovoltaic inverters. Internal electrical loads, as shown in Figure 4, for example, the internal electrical loads can also be fans, air conditioners, firefighting equipment, and lighting equipment in the optical storage off-grid system.

Among them, the self-protection method of the optical storage off-grid system in this embodiment uses the energy management unit EMS as the core brain of the optical storage off-grid system to establish a communication connection with each device in the system, as shown in the figure 3. The energy management unit EMS can collect the operating parameters of each device and control the operation of each device, so as to realize the self-protection of the optical storage off-grid system under the micro-power, including steps:

S01. Control the photovoltaic power generation unit of the solar-storage off-grid system in a sunny environment to supply power to the external and internal power loads, and to charge the battery energy storage unit;

S02. When the photovoltaic power generation unit is not working, control the inverter output of the battery energy storage unit to supply power to the external power load and the internal power load.

That is, when the solar-storage off-grid system has sufficient sunlight during the day, the external power load and the internal power load mainly use the power generated by the photovoltaic power generation unit through photovoltaic power generation, and at the same time, the excess power generated by the photovoltaic power generation unit will be consumed by the battery energy storage unit. Nano, store the electricity in the energy storage battery, and output it when power generation is needed. At the same time, the energy management system EMS can limit the power generation of the photovoltaic inverter after the energy storage battery is fully charged, and control the sum of the power consumption of the internal and external loads to be equal to the power of photovoltaic power generation, so as to ensure that the photovoltaic storage off-grid system maintains full power. stable operating state.

On rainy days or at night, that is, when the photovoltaic power generation system fails to work and stops generating power, the power stored in the energy storage battery can be output through the energy storage converter PCS inverter to supply power to internal and external loads, ensuring that the photovoltaic power storage The normal operation of the grid system and the provision of normal power services for external power loads.

At the same time, as shown in Figure 1, the energy management unit EMS will also obtain the power value of the energy storage battery in real time, and control the timing of the system's self-maintenance through the power value. As shown in Figure 1, including steps:

Wherein, in this embodiment, the energy management unit EMS can obtain the power value of the energy storage battery in real time through communication with the battery management system BMS.

S2. According to the threshold range of the power value, control the on-off of the external load contactor and the internal load contactor in the optical storage off-grid system. The external load contactor is connected to the external electrical load, and the internal load contactor is connected to the optical storage off-grid. The system's internal power load, the minimum value of the threshold range is the power that the battery energy storage unit can support the photovoltaic power generation unit to start once.

Wherein, in this embodiment, step S2 specifically includes the following steps:

S21. When the power value is greater than 30% of the storage capacity of the battery energy storage unit, control the battery energy storage unit to continue supplying power to the external electric load and the internal electric load.

S22. When the power value is 20%~30% of the storage capacity, control the secondary load contactor to disconnect, and cut off the power supply of the battery energy storage unit to the external electric load connected to the secondary load contactor, only for the main load The external electrical load connected to the load contactor and the internal electrical load are powered.

S23. When the power value is 10%~20% of the storage capacity, control the main load contactor to disconnect, cut off the power supply of the battery energy storage unit to the external electric load connected to the main load contactor, and only supply power to the internal electric load .

S24. When the power value is less than 10% of the storage capacity, the internal load contactor is controlled to be disconnected, the battery energy storage unit is cut off to supply power to the internal load, and the off-grid optical storage system shuts down and enters a self-protection power dormancy state.

That is, as shown in Figure 5, when the battery SOC<30% (threshold can be set), the EMS controls the secondary load contactor to disconnect and cut off the secondary load power supply circuit. Electric load power supply. When the battery SOC<20% (threshold can be set), the EMS controls the main load contactor to disconnect and cut off the main load power supply circuit. At this time, the optical storage off-grid system only provides power for the operation of the internal power load equipment, and reserves energy storage The battery has sufficient power remaining to ensure that the system can support the power generation of the next photovoltaic power generation unit in the self-consumption mode. When the battery SOC < 10% (threshold can be set) and the battery charging current < 0A, EMS controls the shutdown of the photovoltaic inverter, controls the shutdown of the energy storage converter, controls the high voltage of the energy storage battery, and the equipment in the off-grid system of the solar storage power off, the system enters the self-protection state.

That is, in this embodiment, by obtaining the power value of the battery energy storage unit in real time, and separating the primary and secondary external electrical loads, and connecting the primary and secondary load contactors, according to the battery energy storage unit The threshold block of the stored power value controls the sequential on-off of the external main power load, the external secondary power load and the internal power load. While ensuring that enough power is reserved in the end before entering the self-maintenance state, it also To a certain extent, the duration of the system's self-consumption mode is extended, and the reliability and stability of the continuous operation of the system are improved. In other equivalent embodiments, the threshold interval of the power value can be set according to the actual power consumption situation or the specifications of each power consumption device.

Please refer to Fig. 3 to Fig. 5, embodiment 2 of the present invention is:

A method for self-maintaining electricity under low power conditions of the optical storage off-grid system. On the basis of the first embodiment above, in this embodiment, as shown in FIG. 3, the optical storage off-grid system also includes an uninterruptible power supply UPS, wherein The energy management unit EMS is communicatively connected with the uninterruptible power supply UPS. In this embodiment, as shown in Figure 4, the uninterruptible power supply UPS is connected to the AC bus in the optical storage off-grid system, and the uninterruptible power supply UPS has a built-in battery. When the AC bus terminal has a voltage input, the photovoltaic power generation unit or battery The energy storage unit charges it; when there is no voltage input at the AC bus terminal, the built-in battery of the uninterruptible power supply UPS can supply power for the back-end precision instruments and equipment of the optical storage off-grid system, such as the control coil of the external and internal load contactors , battery management system BMS, energy management unit EMS and electric energy meter, etc., until the power of the built-in battery is exhausted. In this embodiment, the energy management unit EMS can issue a shutdown command to the uninterruptible power supply UPS to cut off all power consumption and allow the energy storage The power of the system battery and UPS built-in battery is sufficient to last until the next system restart.

Wherein, in the present embodiment, steps are also included after step S2:

S31. In a sunny environment, the internal load contactor is controlled to be closed under the power supply of the uninterruptible power supply, and the battery energy storage unit is started.

S32. The battery energy storage unit inverts and outputs the remaining power to the photovoltaic power generation unit, and starts the photovoltaic power generation unit.

S33. The photovoltaic power generation unit charges the battery energy storage unit and the uninterruptible power supply through photovoltaic power generation, and supplies power for internal and external electric loads, and the off-grid photovoltaic storage system completes self-starting.

That is, as shown in Figure 5, when the off-grid optical storage system enters the self-protection shutdown state, if it is necessary to restart the off-grid optical storage system to restore normal operation, it can be done in a sunny environment, that is, under sufficient light conditions, such as From 9:00 am to 12:00 am on the same day, if the weather is determined to be good and there is no rain for at least two hours, automatically set the uninterruptible power supply to start or manually (professional trained after-sales staff) to start the uninterruptible power supply UPS, The uninterruptible power supply UPS relies on the inverter output of the built-in battery to supply power to the energy management unit EMS. After the energy management unit EMS is started and initialized, it enters the control interface. First, it judges whether the battery energy storage unit is normal. The control coil of the internal DC high-voltage relay connected to the battery energy storage unit pulls in, and the energy storage battery outputs DC power. At this time, the energy management unit EMS establishes communication with the energy storage converter PCS, and controls the energy storage converter PCS to invert the DC power. After the output is stable AC, it is sent to the photovoltaic power generation unit. After the photovoltaic inverter detects that the power supply at the AC bus terminal is normal, it starts to run automatically, and the power generated by the photovoltaic module is incorporated into the AC bus. The off-grid optical storage system starts successfully.

After the system is restored, the photovoltaic power generation unit will first charge the energy storage battery and supply power for the internal electrical loads in the photovoltaic storage off-grid system. At the same time, in this embodiment, the uninterruptible power supply UPS can also be supplemented by the photovoltaic power generation unit at this stage. The power of its built-in battery, and the back-end precision instruments and equipment that are powered by the uninterruptible power supply UPS can also be switched to be powered by photovoltaic power generation units. When the SOC of the energy storage battery reaches 30%, the energy management unit EMS controls the control coil of the main load contactor to pull in, and the solar storage off-grid system gives priority to supplying power to the external main load; when the SOC of the energy storage battery continues to rise to 40%, the energy management unit EMS controls the secondary load contactor to pull in, and the solar storage off-grid system supplies power to the external main load and the external secondary load at the same time. The energy management unit EMS constantly regulates the movement of each device and device according to the power generation and power consumption of each device and the remaining power of the energy storage battery, so as to realize the intelligent, safe, stable and reliable operation of the optical storage off-grid system.

Please refer to Fig. 6, embodiment three of the present invention is:

A self-protection electric terminal 1 under the micro-power of the optical storage off-grid system, including a memory 2, a processor 3, and a computer program stored in the memory 2 and operable on the processor 3, when the processor 3 executes the computer program Realize the steps in a method for self-maintaining power in a light power storage off-grid system as in Embodiment 1 or Embodiment 2 above.

To sum up, the present invention provides a self-protection method and terminal for optical storage off-grid system with low power, which has the following beneficial effects:

1. Increase the main and secondary load contactors. According to the reduction range of the energy storage battery power value, the power supply to the external main power load and the secondary power load is successively disconnected, that is, when the power of the energy storage battery is low, the power supply to the external power load is avoided. External load power supply prolongs the duration of the system in self-consumption mode and improves the reliability and stability of the continuous operation of the system.

2. On the basis of the communication between the energy management unit EMS and the uninterruptible power supply UPS, add a shutdown command to the UPS, and cut off all power consumption when the battery is low, so that the power of the energy storage system battery and the built-in battery of the UPS is sufficient to maintain until next time the system reboots.

3. For areas without mains electricity, customers do not need to add diesel generators, which can save investment costs.

4. Save maintenance costs, the system restart operation is simple, greatly reduce the frequency of on-site maintenance, and save labor costs, travel expenses, food and accommodation expenses caused by the maintenance process.

The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent transformations made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in related technical fields, are all included in the same principle. Within the scope of patent protection of the present invention.

Claims

A method for self-maintaining electricity in a light-storage off-grid system under micro-power conditions, characterized in that it includes the steps of:

S1. Obtain the power value of the battery energy storage unit in the optical storage off-grid system in real time;

S2. According to the threshold range where the electricity value is located, control the sequential on-off of the external load contactor and the internal load contactor in the optical-storage off-grid system, the external load contactor is connected to the external electrical load, and the internal load contactor The load contactor is connected to the internal power load of the photovoltaic storage off-grid system, and the minimum value of the threshold range is the amount of electricity that the battery energy storage unit can support to start the photovoltaic power generation unit once.
According to claim 1, a method for self-maintaining electricity in a light-storage off-grid system with a small amount of power, wherein the external load contactor includes a main load contactor and a secondary load contactor, and the external power supply The load chooses to connect the main load contactor or the secondary load contactor according to the power consumption requirements;

Described step S2 specifically comprises:

S21. When the power value is greater than 30% of the storage capacity of the battery energy storage unit, control the battery energy storage unit to continue supplying power to the external electric load and the internal electric load;

S22. When the power value is 20% to 30% of the storage capacity, control the secondary load contactor to disconnect, and cut off the battery energy storage unit as the secondary load contactor. The power supply of the external electric load, only supplies power to the external electric load and the internal electric load connected to the main load contactor;

S23. When the power value is 10% to 20% of the storage capacity, control the main load contactor to disconnect, and cut off the battery energy storage unit as the external power supply connected to the main load contactor. The power supply of the electric load, only supplies power to the internal electric load;

S24. When the power value is less than 10% of the storage capacity, control the internal load contactor to disconnect, cut off the power supply of the battery energy storage unit to the internal electric load, and the optical storage off-grid system Shut down and enter the self-protection power sleep state.
The self-protection method of an optical storage off-grid system with a small amount of power according to claim 1, characterized in that, before the step S1, it also includes:

S01. Control the photovoltaic power generation unit of the solar-storage off-grid system to supply power to the external power load and the internal power load in a sunny environment, and charge the battery energy storage unit;

S02. When the photovoltaic power generation unit is not working, control the inverter output of the battery energy storage unit to supply power for the external electric load and the internal electric load.
According to claim 3, a method for self-maintaining electricity under low power of the optical storage off-grid system, characterized in that, the optical storage off-grid system also includes an uninterruptible power supply, and the uninterruptible power supply is generated by the photovoltaic The unit or the battery energy storage unit is charged, and the uninterruptible power supply supplies power for the back-end precision instruments and equipment of the optical storage off-grid system.
A method for self-maintaining electricity in a light-storage off-grid system according to claim 4, characterized in that, after the step S2, it also includes:

S31. In a sunny environment, control the internal load contactor to be closed under the power supply of the uninterruptible power supply, and start the battery energy storage unit;

S32. The battery energy storage unit inverts and outputs the remaining power to the photovoltaic power generation unit, and starts the photovoltaic power generation unit;

S33. The photovoltaic power generation unit charges the battery energy storage unit and the uninterruptible power supply through photovoltaic power generation, supplies power for the internal electric load and the external electric load, and the optical storage off-grid system completes the automatic start up.
A self-guaranteed power terminal for light-storage off-grid systems with low power consumption, characterized in that the terminal is an energy management unit, and the energy management unit includes a memory, a processor, and stored in the memory and can run on the processor A computer program, the processor implements the following steps when executing the computer program:

S1. Obtain the power value of the battery energy storage unit in the optical storage off-grid system in real time;

S2. According to the threshold range where the electricity value is located, control the sequential on-off of the external load contactor and the internal load contactor in the optical-storage off-grid system, the external load contactor is connected to the external electrical load, and the internal load contactor The load contactor is connected to the internal power load of the photovoltaic storage off-grid system, and the minimum value of the threshold range is the amount of electricity that the battery energy storage unit can support to start the photovoltaic power generation unit once.
According to claim 6, a kind of self-protection power terminal of the off-grid optical storage system under micro-power, characterized in that, the external load contactor includes a main load contactor and a secondary load contactor, and the external power supply The load chooses to connect the main load contactor or the secondary load contactor according to the power consumption requirements;

Described step S2 specifically comprises:

S21. When the power value is greater than 30% of the storage capacity of the battery energy storage unit, control the battery energy storage unit to continue supplying power to the external electric load and the internal electric load;

S22. When the power value is 20% to 30% of the storage capacity, control the secondary load contactor to disconnect, and cut off the battery energy storage unit as the secondary load contactor. The power supply of the external electric load, only supplies power to the external electric load and the internal electric load connected to the main load contactor;

S23. When the power value is 10% to 20% of the storage capacity, control the main load contactor to disconnect, and cut off the battery energy storage unit as the external power supply connected to the main load contactor. The power supply of the electric load, only supplies power to the internal electric load;

S24. When the power value is less than 10% of the storage capacity, control the internal load contactor to disconnect, cut off the power supply of the battery energy storage unit to the internal electric load, and the optical storage off-grid system Shut down and enter the self-protection power sleep state.
According to claim 6, a kind of self-protection power terminal of the optical storage off-grid system under micro-power, characterized in that, before the step S1, it also includes:

S01. Control the photovoltaic power generation unit of the solar-storage off-grid system to supply power to the external power load and the internal power load in a sunny environment, and charge the battery energy storage unit;

S02. When the photovoltaic power generation unit is not working, control the inverter output of the battery energy storage unit to supply power for the external electric load and the internal electric load.
According to claim 8, a self-guaranteed power terminal of a light-storage off-grid system under micro-power conditions, wherein the light-storage off-grid system also includes an uninterruptible power supply, and the uninterruptible power supply is generated by the photovoltaic The unit or the battery energy storage unit is charged, and the uninterruptible power supply supplies power for the back-end precision instruments and equipment of the optical storage off-grid system.
According to claim 9, a self-protection power terminal of an optical storage off-grid system under micro-power, characterized in that, after the step S2, it also includes:

S31. In a sunny environment, control the internal load contactor to be closed under the power supply of the uninterruptible power supply, and start the battery energy storage unit;

S32. The battery energy storage unit inverts and outputs the remaining power to the photovoltaic power generation unit, and starts the photovoltaic power generation unit;

S33. The photovoltaic power generation unit charges the battery energy storage unit and the uninterruptible power supply through photovoltaic power generation, supplies power for the internal electric load and the external electric load, and the optical storage off-grid system completes the automatic start up.