Light storage integrated system and energy control method

Abstract

The invention provides a light storage integrated system and an energy control method. The light storage integrated system comprises a light storage module, a light stacking module and an alternating current-to-direct current module which are connected in parallel to a direct current bus, the light storage module comprises at least one group of light storage units, a first photovoltaic panel in each light storage unit is connected with a first end of a first photovoltaic controller, a second end of the first photovoltaic controller is connected to a DC bus through a bidirectional DC-DC module, and an energy storage battery is connected with a second end of the first photovoltaic controller; the installed capacity of the optical storage module is more than 0.8 time of the load power; the light stacking module converts light energy into electric energy and provides the electric energy to the direct-current bus; the installed capacity of the stacked light module is 0.8-1.2 times of the load power; the AC-to-DC module converts AC provided by the power grid into DC and provides the DC to the DC bus. According to the invention, the fluctuation of bus voltage is effectively reduced, the photovoltaic light abandoning phenomenon is avoided, and the utilization rate of photovoltaic power generation, power generation benefits and system reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy, and in particular to a photovoltaic-storage integrated system and an energy control method. Background Art

[0002] Green energy, also known as clean energy or renewable energy, refers to energy types that have less impact on the environment and low pollution emissions during the production process. These energy sources mainly include solar energy, wind energy, water energy (hydropower), biomass energy, geothermal energy, etc. Green energy has the characteristics of being renewable, environmentally friendly, and low-carbon. It is an important energy choice for responding to global climate change and achieving sustainable development.

[0003] As a major energy consumer, the communications industry faces tremendous pressure to save energy and reduce emissions. Traditional AC stacked optical systems have many conversion levels, low power generation efficiency, and a long investment payback period. Against this background, the integrated photovoltaic storage technology for communication base stations came into being. This technology achieves energy self-sufficiency and green power supply for communication base stations by integrating photovoltaic power generation and energy storage systems. Photovoltaic power generation systems use solar energy, a clean and renewable energy source, to convert light energy into electrical energy, providing a continuous power supply for communication base stations. At the same time, the energy storage system reduces electricity costs by shaving peaks and filling valleys, and absorbs more solar energy.

[0004] Although many base stations have installed energy storage systems or photovoltaic systems, they only use energy storage for peak-valley arbitrage or use photovoltaics for DC photovoltaic stacking. In addition, when using photovoltaics for DC photovoltaic stacking, if the photovoltaic installed capacity is greater than the load, it will cause large fluctuations in bus voltage; therefore, when installing photovoltaics at base stations, considering the safety of the base station power supply system, the photovoltaic installed capacity of most base stations will be less than the load power, which causes most base stations to waste photovoltaic resources and reduce the yield of photovoltaics.

[0005] How to propose an efficient, reliable and green communication base station energy solution has become one of the urgent problems to be solved by technical personnel in this field.

[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an integrated photovoltaic and energy storage system and an energy control method, so as to solve the problems of low efficiency and low reliability of the integrated photovoltaic and energy storage system in the prior art.

[0008] In order to achieve the above-mentioned object and other related objects, the present invention provides a photovoltaic storage integrated system, the photovoltaic storage integrated system comprising:

[0009] The optical storage module, the stacked optical module and the AC-DC converter module are connected in parallel to the DC bus;

[0010] The photovoltaic storage module includes at least one group of photovoltaic storage units, each photovoltaic storage unit includes a first photovoltaic panel, a first photovoltaic controller, an energy storage battery and a bidirectional DC-DC module, wherein the first photovoltaic panel is connected to the first end of the first photovoltaic controller, the second end of the first photovoltaic controller is connected to the DC bus via the bidirectional DC-DC module, and the energy storage battery is connected to the second end of the first photovoltaic controller; the installed capacity of the photovoltaic storage module is n times the load power, where n is a number greater than or equal to 0.8;

[0011] The stacked light module converts light energy into electrical energy and provides it to the DC bus; the installed capacity of the stacked light module is 0.8 to 1.2 times the load power;

[0012] The AC-DC module converts AC power provided by the power grid into DC power, and provides the DC power to the DC bus.

[0013] Optionally, the stacked light module includes at least one group of stacked light units, each stacked light unit includes a second photovoltaic panel and a second photovoltaic controller, and the second photovoltaic panel is connected to the DC bus via the second photovoltaic controller.

[0014] In order to achieve the above-mentioned purpose and other related purposes, the present invention further provides an energy control method, which is implemented based on the above-mentioned photovoltaic storage integrated system, and the energy control method at least includes:

[0015] In the first power demand period, the power grid supplies power to the load on the DC bus, and based on the bidirectional DC conversion module, the power on the power grid is stored in the energy storage battery, and the charging amount of the energy storage battery is determined by the power generated in the previous photovoltaic power generation cycle;

[0016] In the second power demand period, the stacked light module and the light storage module supply power to the load, the photovoltaic multi-generation energy in the light storage module is stored in the energy storage battery, and the working state of the energy storage battery is dynamically adjusted according to the photovoltaic power generation based on the bidirectional DC conversion module, and the priority of the stacked light module is higher than that of the light storage module;

[0017] In the third power demand period, the stacked optical module, the optical storage module and the power grid supply power to the load, and the priorities of the stacked optical module, the optical storage module and the power grid decrease in sequence;

[0018] Among them, the first power demand period, the second power demand period and the third power demand period are arranged in a cycle in sequence; the first power demand period is a trough period, the second power demand period is a flat period, and the third power demand period is a peak period and / or a spike period.

[0019] Optionally, during the first power demand period, a predicted SOC of the energy storage battery is obtained based on the photovoltaic power generation and load power consumption in the previous photovoltaic power generation cycle, and charging is stopped when the energy storage battery is charged to the predicted SOC.

[0020] More optionally, the predicted SOC is the ratio of the difference between the battery nominal capacity and the amount of electricity provided to the energy storage battery by photovoltaic power generation in the previous photovoltaic power generation cycle to the battery nominal capacity.

[0021] Optionally, in the starting period of the second power demand period, the energy storage battery is controlled to discharge based on the bidirectional DC conversion module;

[0022] In the middle period of the second power demand period, judging whether the energy storage battery is discharged according to the relationship between the average photovoltaic power generation power and the load power of the day;

[0023] At the end of the second power demand period, the energy storage battery is controlled to be fully charged based on the bidirectional DC conversion module.

[0024] Optionally, when a third power demand period is provided between the first power demand period and the second power demand period,

[0025] In the starting period and the middle period of the second power demand period, judging whether the energy storage battery is discharged according to the relationship between the average photovoltaic power generation power and the load power of the day;

[0026] At the end of the second power demand period, the energy storage battery is controlled to be fully charged based on the bidirectional DC conversion module.

[0027] More optionally, the start time period is set to 1 hour to 4 hours, and the end time period is set to 1 hour to 4 hours.

[0028] More optionally, in the starting period and the middle period of the second power demand period, the method for determining whether the energy storage battery is discharged comprises: if P PVaver ≥K1*P Load , the energy storage battery discharges; otherwise, the energy storage battery does not discharge;

[0029] Among them, P PVaver is the average photovoltaic power generation of the day; K1 is the discharge judgment coefficient, K1∈[0.5,2]; P Loadis the load power of the day.

[0030] More optionally, when the middle period of the second power demand period is embedded in the first power demand period, during the first power demand period embedded in the second power demand period, the working status of the energy storage battery is judged based on the relationship between the average photovoltaic power generation power and the load power on that day.

[0031] More optionally, within the first power demand period embedded in the second power demand period, if P PVaver ≥K1*P Load , then the energy storage battery is controlled to discharge based on the bidirectional DC conversion module; if P PVaver <K2*P Load , the energy storage battery is charged based on the bidirectional DC conversion module; otherwise, the bidirectional DC conversion module does not work;

[0032] Among them, P PVaver is the average photovoltaic power generation power of the day; P Load is the load power of the day; K1 is the discharge judgment coefficient, K1∈[0.5,2]; K2 is the charge judgment coefficient, K2∈(0,0.5].

[0033] More optionally, when a second power demand period is set between the third power demand period and the first power demand period, the energy storage battery is discharged to a set SOC during the second power demand period between the third power demand period and the first power demand period, and the set SOC is not greater than 30%.

[0034] More optionally, when charging the energy storage battery, the bidirectional DC-to-DC module controls the voltage of the energy storage battery, and the maximum limit value of the voltage loop output is set to positive, and the minimum limit value is set to negative; when discharging the energy storage battery, the bidirectional DC-to-DC module controls the DC bus voltage, and the control voltage target value is greater than the output voltage value of the AC-to-DC module, the maximum limit value of the voltage loop output is set to negative, and the minimum limit value is set to negative.

[0035] As described above, the integrated photovoltaic and energy storage system and energy control method of the present invention have the following beneficial effects:

[0036] 1. The photovoltaic output power of the present invention can reach 2 to 4 times of the load power, which can realize direct photovoltaic generation and direct use, and multiple generation and storage. It can ensure that every ray of sunlight can be converted into clean electricity to the maximum extent, and in principle there is no reverse flow of the power grid, which sets a new benchmark for the application of green energy.

[0037] 2. The present invention proposes a highly efficient, modular DC microgrid power supply system, which innovates the system topology and simplifies the energy conversion process. When the sun is sufficient, the electricity generated by the photovoltaic panel is directly input into the DC bus through the MPPT controller, and the excess electricity can also be directly stored in the energy storage battery; when the photovoltaic power is insufficient or the electricity price is at peak time, it automatically switches to the energy storage battery for power supply; if the energy storage power is also insufficient, it is seamlessly connected to the mains. The system efficiency is improved while also ensuring the stability of the DC bus voltage. This innovative architecture lays a solid foundation for building a greener, smarter and more sustainable energy ecosystem.

[0038] 3. The present invention realizes seamless intelligent switching among photovoltaic, energy storage and city electricity through a comprehensive energy management and scheduling algorithm, forming a power supply system with three complementary sources, ensuring the power generation performance of the system, and globally optimizing energy production, storage, distribution and consumption to achieve maximum utilization and optimal configuration of energy. It can not only realize intelligent management of peak-shifting energy storage and peak-filling, but also ensure continuous and stable power supply without fear of any weather and time challenges, truly realizing the integration of "source, grid, load and storage". BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Shown is a schematic structural diagram of the integrated optical-storage system of the present invention.

[0040] Figure 2 Shown is a schematic structural diagram of the bidirectional DC-DC module of the present invention.

[0041] Figure 3 Shown is a schematic diagram of the communication architecture of the integrated optical-storage system of the present invention.

[0042] Figure 4 The first example of the energy control method of the present invention is shown.

[0043] Figure 5 The second example of the energy control method of the present invention is shown.

[0044] Figure 6 A third example of the energy control method of the present invention is shown.

[0045] Figure 7 A fourth example of the energy control method of the present invention is shown.

[0046] Component number description

[0047] 1. Optical-storage integrated system

[0048] 11 Optical storage module

[0049] 11a The first photo storage unit

[0050] 11b Second photo storage unit

[0051] 111 First Photovoltaic Panel

[0052] 112 First Photovoltaic Controller

[0053] 113 Bidirectional DC to DC Module

[0054] 113a Voltage loop

[0055] 113b Current loop

[0056] 12 stacked light modules

[0057] 12a First stack light unit

[0058] 12b Second stacking light unit

[0059] 121 Second photovoltaic panel

[0060] 122 Second photovoltaic controller

[0061] 13 AC to DC Module

[0062] 14 Remote monitoring module

[0063] 15 Display

[0064] 16 Central Controller DETAILED DESCRIPTION

[0065] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0066] See also Figure 1 to Figure 7 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0067] like Figure 1 As shown, the present invention provides a photovoltaic storage integrated system 1, which includes: a photovoltaic storage module 11, a stacked optical module 12 and an AC to DC module 13 connected in parallel to a DC bus BUS; and is used to supply power to a DC load.

[0068] like Figure 1As shown, the photovoltaic storage module 11 includes at least one group of photovoltaic storage units, and each group of photovoltaic storage units is connected in parallel to the DC bus BUS.

[0069] Specifically, in this embodiment, the photo-storage module 11 includes two groups of photo-storage units, which are recorded as the first photo-storage unit 11a and the second photo-storage unit 11b. The structures of the photo-storage units are the same. Taking the first photo-storage unit 11a as an example, it includes a first photovoltaic panel 111, a first photovoltaic controller 112 (MPPT controller), an energy storage battery C1 and a bidirectional DC-to-DC module 113. Among them, the first photovoltaic panel 111 converts solar energy into electrical energy. The first end of the first photovoltaic controller 112 is connected to the first photovoltaic panel 111 to control the first photovoltaic panel 111 to output at maximum power. The energy storage battery C1 is connected to the second end of the first photovoltaic controller 112 for storing energy. One end of the bidirectional DC-to-DC module 113 is connected to the second end of the first photovoltaic controller 112, and the second end is connected to the DC bus BUS, which is used to realize bidirectional energy conversion between the energy storage battery C1 and the DC bus BUS.

[0070] More specifically, if Figure 2 As shown, in this embodiment, the bidirectional DC-DC converter module 113 includes a voltage loop 113a and a current loop 113b. The voltage loop 113a controls the voltage feedback signal U fbk With the reference voltage U given by the system ref The difference between the current and the reference current is obtained by limiting the current (limiting the maximum current). ref , voltage feedback signal U fbk The sampled value of the battery voltage or bus voltage is obtained through the switch; the current loop 113b is connected to the output end of the voltage loop 113a, based on the current feedback signal I CS With the current reference value I ref The difference between the feedback value and the current value is calculated to obtain the control voltage D of the switch (the switch control signal before correction); wherein, the voltage loop 113a and the current loop 113b both include a difference operator and a proportional integral (PI) controller, the difference operator subtracts the feedback value from the given value (voltage reference value or current reference value) to obtain the difference, and the proportional integral controller performs a proportional integral operation on the difference to realize the voltage loop or current loop control to obtain the corrected control quantity D. As an example, a correction unit (not shown in the figure) may also be provided at the output end of the current loop, and the correction unit is implemented by an adder. In actual use, it may also be implemented by an operator including but not limited to a subtractor, and may be provided as required; the correction unit may also be removed, and is not limited to this embodiment.

[0071] In this example, when charging the energy storage battery C1, the bidirectional DC-DC converter 113 controls the voltage of the energy storage battery C1, and the voltage loop output (ie, the current reference value I ref )The maximum limit value is set to positive and the minimum limit value is set to negative.

[0072] In this example, when the energy storage battery C1 is discharged, the bidirectional DC-to-DC module 113 controls the DC bus voltage Vbus, and the control voltage target value is greater than the output voltage value of the AC-to-DC module 13, and the voltage loop output maximum limit value is set to negative, and the minimum limit value is set to negative.

[0073] It should be noted that in actual use, the number of photovoltaic storage units is configured according to actual needs, so that the installed capacity of the photovoltaic storage module 11 is n times the load power, n is a number greater than or equal to 0.8, including but not limited to 1, 1.2, 1.5, 2, 3, 5; the load power can be set remotely, or the average load power can be calculated by sampling. In addition, each energy storage battery C1 can be configured as a single battery, or as a series connection, parallel connection, or series-parallel connection of two or more batteries.

[0074] like Figure 1 As shown, the stacked light module 12 converts light energy into electrical energy and provides it to the DC bus BUS.

[0075] Specifically, the stacked light module 12 includes at least one group of stacked light units, and each stacked light unit is connected in parallel to the DC bus BUS. In this embodiment, the stacked light module 12 includes two groups of stacked light units, which are recorded as the first stacked light unit 12a and the second stacked light unit 12b. The structure of each stacked light unit is the same. Taking the first stacked light unit 12a as an example, it includes a second photovoltaic panel 121 and a second photovoltaic controller 122 (MPPT controller). Among them, the second photovoltaic panel 121 converts solar energy into electrical energy. The first end of the second photovoltaic controller 122 is connected to the second photovoltaic panel 121 to control the second photovoltaic panel 121 to output at maximum power; the second end of the second photovoltaic controller 122 is connected to the DC bus BUS.

[0076] It should be noted that in actual use, the number of stacked light units is configured according to actual needs, and the installed capacity of the stacked light module 12 is configured to be 0.8 to 1.2 times the load power, including but not limited to 0.9 times, 1 times, and 1.1 times. The photovoltaic power generation of each stacked light unit can directly power the load, and the photoelectric conversion efficiency is optimal.

[0077] When the total photovoltaic power generation of the system is greater than the load power, the excess energy of the photovoltaic power generation of the photovoltaic storage unit is first directly stored in the energy storage battery, and the other part of the photovoltaic power generation of the photovoltaic storage unit is used to supply power to the load together with the photovoltaic power generation energy of the stacked light unit through the bidirectional DC-DC module. When the photovoltaic power generation power is less than the load power, and during the first power or second power demand period, the energy stored in the energy storage battery is released through the bidirectional DC-DC module to supply power to the load. It can be seen that the conversion of photovoltaic energy of the photovoltaic storage unit does not have to go through the bidirectional DC-DC module to charge and discharge the battery like traditional control, and the efficiency is also optimal.

[0078] Furthermore, since the photovoltaic capacity configuration of the stacked light unit is similar to the load power, under good light conditions, the photovoltaic power generation of the stacked light unit can just meet the load consumption, and at this time the photovoltaic power generation of the photovoltaic storage unit is all used to charge the energy storage battery. When the energy storage battery is full, the photovoltaic controller of the photovoltaic storage unit will operate at limited power; and when the light suddenly deteriorates, the photovoltaic power generation of the stacked light unit is far from meeting the load consumption, and the photovoltaic storage unit can supply power to the load together with the stacked light unit through a bidirectional DC-DC module, and the bidirectional DC-DC module controls the bus voltage through a voltage loop at this time. It can be seen that the bus voltage will not fluctuate greatly due to drastic changes in light, and the photovoltaic fluctuations are mainly absorbed by the energy storage battery of the energy storage unit, which greatly improves the stability and reliability of the system.

[0079] The communication architecture of the integrated optical storage system 1 of the present invention is as follows: Figure 3 As shown, the remote monitoring module 14 is connected to the display screen 15, and controls the photovoltaic storage integrated equipment (photovoltaic controller, bidirectional DC-to-DC module) in the communication base station through the central controller 16, and remotely sets the peak and valley charging and discharging time of the energy storage battery, the equalizing charging voltage, the floating charging voltage and other parameters of the energy storage battery.

[0080] The integrated photovoltaic and storage system of the present invention is highly intelligent, collects operating data in real time, and adaptively adjusts the operating mode according to the operating status without manual intervention, thus reducing operation and maintenance costs; the system has a high degree of integration and adopts an integrated design to reduce product energy consumption costs and achieve significant economic benefits; the system has high safety, and each electrical equipment and system has multiple protections. The operating data is monitored in real time through a big data cloud platform, providing safe, clean, reliable and cheap electricity for the stable operation of the system.

[0081] The present invention also provides an energy control method, which aims to formulate a reasonable charging and discharging plan based on the actual situation of the power market, the power demand of the communication base station and the technical characteristics of the photovoltaic storage system, so as to achieve the goals of full utilization of photovoltaic energy, peak-shifting energy storage, and energy conservation and emission reduction. The energy control method of the present invention is implemented based on the photovoltaic storage system 1, and includes:

[0082] In the first power demand period, the power grid supplies power to the load on the DC bus BUS, and stores the power on the grid into the energy storage battery based on the bidirectional DC conversion module. The charging amount of the energy storage battery is determined by the power generated in the previous photovoltaic power generation cycle;

[0083] In the second power demand period, the stacked photoelectric module and the photoelectric storage module supply power to the load, the photovoltaic multi-generation energy in the photoelectric storage module is stored in the energy storage battery, and the working state of the energy storage battery is dynamically adjusted according to the photovoltaic power generation based on the bidirectional DC conversion module, and the priority of the stacked photoelectric module is higher than that of the photoelectric storage module;

[0084] In the third power demand period, the stacked optical module, the optical storage module and the power grid supply power to the load, and the priorities of the stacked optical module, the optical storage module and the power grid decrease in sequence;

[0085] Among them, the first power demand period, the second power demand period and the third power demand period are set in sequence in a cycle; the first power demand period is a trough period, the second power demand period is a flat period, and the third power demand period is a peak period and / or a spike period.

[0086] As a first example, Figure 4 As shown, the 24 hours of a day are divided into three power demand periods, wherein the first power demand period (trough) starts from 24:00 and ends at 9:00, the second power demand period (flat) starts from 9:00 and ends at 16:00, and the third power demand period (peak / spike) starts from 16:00 and ends at 24:00. The start and end nodes of each period can be determined based on the actual power consumption in each region, and are not limited to this embodiment.

[0087] The first power demand period is generally set to the period of relatively low power consumption at night and in the morning. During the first power demand period, the photovoltaic panels basically do not generate electricity, the power consumption of the load is greatly reduced, and the electricity price is relatively low; at this time, the load is powered by the power grid, and the energy storage battery C1 in the photovoltaic storage module 11 is charged through the power grid.

[0088] Specifically, as an example, in this charging stage, the predicted SOC of the energy storage battery is obtained based on the photovoltaic power generation and load power consumption in the previous photovoltaic power generation cycle T1. When the energy storage battery C1 is charged to the predicted SOC, charging is stopped to limit the charging amount, thereby ensuring that the solar energy of the next photovoltaic power generation cycle is fully utilized and stored; wherein the photovoltaic power generation cycle is the period of time during the day when photovoltaics convert solar energy into electrical energy (for example, from 9:00 to 17:00 every day). Further, in this embodiment, the predicted SOC is the ratio of the difference between the battery nominal capacity and the power provided by photovoltaics to the energy storage battery in the previous photovoltaic power generation cycle to the battery nominal capacity, satisfying:

[0089] SOC est =1-(W PV(T1) -W load(T1) ) / W bat (1);

[0090] Among them, SOC est To predict SOC, W PV(T1) -W load(T1) The amount of electricity charged to the energy storage battery by photovoltaic power generation in the last photovoltaic power generation cycle, W batIt is the nominal energy of the energy storage battery (i.e., the kWh number of the battery). In actual use, any method that can predict the battery SOC to reserve energy storage space for the next photovoltaic power generation cycle is applicable to the present invention, and is not limited to this embodiment.

[0091] Specifically, as an example, in this charging stage, the bidirectional DC-DC conversion module 113 controls the energy storage battery C1, and the energy storage battery C1 is charged in an equalization charging mode, satisfying:

[0092] I bat =K4·(1-SOC actu )·B Ah / (T end -T now ) (2);

[0093] U ref =U Cref (3);

[0094] Among them, I bat is the charging current of the energy storage battery; K4 is the charging coefficient of the energy storage battery, K4∈(1,1.5), including but not limited to 1.2, 1.3, 1.4; SOC actu is the actual SOC of the energy storage battery (a number between 0 and 1); B Ah is the rated capacity of the energy storage battery (i.e. the number of Ah of the battery), T end is the end time of the first power demand period, T now is the current time, U ref is the reference voltage given by the system, U Cref is the equalizing charging voltage given by the system.

[0095] The second power demand period is set as a period during the day when power consumption is relatively low. During the second power demand period, when there is sufficient sunlight, the photovoltaic panels convert solar energy into electrical energy. Compared with the first power demand period, the amount of electricity consumed by the load increases and the electricity price increases. At this time, the electric energy generated by the stacked photoelectric module 12 is used to power the load first. When the electric energy provided by the stacked photoelectric module 12 is insufficient, it is supplemented by the photovoltaic storage module 11. The excess photovoltaic energy in the photovoltaic storage module 11 is stored in the energy storage battery C1, and the working state of the energy storage battery C1 is dynamically adjusted according to the photovoltaic power generation.

[0096] Specifically, in this embodiment, the second power demand period is divided into three periods, which are respectively recorded as the starting period, the middle period and the ending period. The duration of the starting period and the ending period is set as an empirical value, and different empirical values ​​can be given according to different regions, for example, it is set to 1 hour-4 hours. As an example, the starting period is set to 2, 2.3, 2.5, 3, 3.2, 3.5 or 3.8 hours, and the ending period is set to 2, 2.5, 2.7, 3, 3.3, 3.5 or 3.7 hours; the period between the starting period and the ending period is the middle period. In this example, the starting stage starts from 9:00 and ends at 11:00, the middle period starts from 11:00 and ends at 14:00, and the ending period starts from 14:00 and ends at 16:00.

[0097] More specifically, in the starting period, the bidirectional DC conversion module 113 controls the energy storage battery C1 to discharge, so as to ensure that the energy storage battery C1 has sufficient capacity to absorb the excess photovoltaic power generation and has the function of peak shaving and valley filling.

[0098] More specifically, in the middle period, the relationship between the average power of photovoltaic power generation and the load power of the day is used to determine whether the energy storage battery C1 is discharged; the average power of photovoltaic power generation on the day is the average power of photovoltaic power generation from the beginning of photovoltaic power generation to the current time. Assuming that photovoltaic power generation starts at 6:00 and the current time is 11:00, the average power of photovoltaic power generation on the day is the average power from 6:00 to 11:00 (5 hours); similarly, the load power on the day is the load power from the beginning of electricity consumption on the day to the current time. As an example, the method for determining whether the energy storage battery is discharged includes: if P PVaver ≥K1*P Load , then the energy storage battery C1 is controlled to discharge, otherwise the energy storage battery C1 is controlled not to discharge. PVaver is the average power of photovoltaic power generation on that day; K1 is the discharge judgment coefficient, K1∈[0.5,2], including but not limited to 0.6, 0.8, 1, 1.3, 1.5, 1.7, 1.9; P Load is the load power of the day.

[0099] More specifically, during the end period, the bidirectional DC conversion module 113 controls the energy storage battery C1 to be fully charged to prepare for peak discharge.

[0100] The third power demand period is set as the period of relatively high power consumption in the evening and at night. In the third power demand period, the photovoltaic panel may only generate electricity in the initial stage, and no electricity is generated in the rest of the period, the load power consumption is greatly increased, and the electricity price is high; at this time, the power generated by the stacked light module 12 is preferentially used to power the load, and then the power stored in the light storage module 11 is used, and the insufficient part is supplemented by the power grid. In this process, the energy storage battery C1 in the light storage module 11 is in a discharging state.

[0101] As a second example, a third power demand period is further provided between the first power demand period and the second power demand period. Figure 5 As shown, 24 hours a day is divided into four power demand periods, wherein the first power demand period (trough) starts from 23:00 and ends at 8:00, the first third power demand period (peak / spike) starts from 8:00 and ends at 11:00, the second power demand period (flat) starts from 11:00 and ends at 16:00, and the second third power demand period (peak / spike) starts from 16:00 and ends at 23:00. The start and end nodes of each period can be determined according to the actual power consumption in each region, and are not limited to this embodiment.

[0102] Specifically, the working principles of the first power demand period and each third power demand period are the same as those of the first example, and are not described in detail here.

[0103] Specifically, in the first third power demand period, the stacked photoelectric module 12, the photoelectric storage module 11, and the power grid supply power to the load in descending order of priority, and the energy storage battery C1 is controlled by the bidirectional DC conversion module 113 to discharge. At this time, since the energy storage battery C1 has been discharged before the second power demand period and storage space is reserved, there is no need to perform a discharge operation at the beginning of the second power demand period. The beginning and middle periods of the second power demand period are based on the relationship between the average power of photovoltaic power generation and the load power of the day to determine whether the energy storage battery C1 is discharged; at the end of the second power demand period, the bidirectional DC conversion module 113 controls the energy storage battery C1 to be fully charged. The specific method is described above and will not be repeated here.

[0104] As a third example, based on the first example or the second example, a first power demand period is further provided in the middle period of the second power demand period. In this example, taking the first example as an example, the first power demand period is provided in the middle period of the second power demand period. Figure 6 As shown, 24 hours a day is divided into five power demand periods, wherein the first power demand period (trough) starts from 24:00 and ends at 6:00, the second power demand period (flat) starts from 6:00 to 12:00, and then from 14:00 to 16:00, the second first power demand period (trough) starts from 12:00 to 14:00, and the third power demand period (peak / spike) starts from 16:00 to 24:00. The start and end nodes of each period can be determined according to the actual power consumption in each region, and are not limited to this embodiment.

[0105] Specifically, the working principles of the first first power demand period and the third power demand period are the same as those in the first example; the second first power demand period is embedded in the middle period of the second power demand period, and the second power demand period is divided into an initial stage, an intermediate stage and an ending stage; the specific working principles are the same as those in the first example and will not be elaborated here.

[0106] Specifically, in the second first power demand period, when the photovoltaic power generation is relatively large, the energy storage battery C1 performs a charging operation; when the photovoltaic power generation is relatively low, the energy storage battery C1 performs a discharging operation. In this example, the photovoltaic power generation is judged based on the relationship between the average photovoltaic power generation and the load power of the day, and then the working state of the energy storage battery C1 is determined. More specifically, if P PVaver ≥K1*P Load , then the bidirectional DC conversion module 113 controls the energy storage battery C1 to discharge. PVaver <K2*P Load , the bidirectional DC conversion module 113 controls the energy storage battery C1 to charge; further, in this example, the bidirectional DC module 113 controls the energy storage battery C1 to charge in an equalizing charging mode, satisfying the above-mentioned relationship equations (2)-(3).

[0107] As a fourth example, based on the first example, the second example or the third example, a second power demand period is further provided between the third power demand period and the first power demand period. In this example, taking the second example as an example, the second power demand period is provided based on the second example. Figure 7 As shown, 24 hours a day is divided into five power demand periods, wherein the first power demand period (trough) starts from 23:00 and ends at 8:00, the first third power demand period (peak) starts from 8:00 and ends at 11:00, the first second power demand period (flat) starts from 11:00 and ends at 16:00, the second third power demand period (peak / spike) starts from 16:00 and ends at 21:00, and the second second power demand period (flat) starts from 21:00 and ends at 23:00. The start and end nodes of each period can be determined according to the actual power consumption in each region, and are not limited to this embodiment.

[0108] Specifically, the working principles of the first power demand period, the first second power demand period, and each third power demand period are the same as those in the second example, and are not described one by one here. In the second second power demand period, the bidirectional DC-DC module 113 controls the energy storage battery C1 to continue discharging until the energy storage battery C1 is discharged to the set SOC; the set SOC can be set according to actual needs. As an example, the set SOC is not greater than 30%, including but not limited to 25%, 20%, 15%, and 10%. When the power provided by the energy storage battery C1 is insufficient, it is supplemented by the power grid to ensure normal power supply to the load.

[0109] In the present invention, in the first power demand period, the bidirectional DC-DC converter module 113 controls the voltage of the energy storage battery C1. In other periods, including but not limited to the second and third power demand periods, the bidirectional DC-DC converter module 113 controls the voltage on the DC bus BUS or the voltage of the energy storage battery C1. This is not described in detail.

[0110] It should be noted that the setting of trough, flat and peak periods is determined by the power department based on the electricity consumption in each region.

[0111] In summary, the present invention provides an integrated photovoltaic and storage system and an energy control method, wherein the integrated photovoltaic and storage system comprises: a photovoltaic and storage module, a stacked photovoltaic module and an AC-to-DC module connected in parallel on a DC bus; the photovoltaic and storage module comprises at least one group of photovoltaic and storage units, each photovoltaic and storage unit comprises a first photovoltaic panel, a first photovoltaic controller, an energy storage battery and a bidirectional DC-to-DC module, wherein the first photovoltaic panel is connected to a first end of the first photovoltaic controller, the second end of the first photovoltaic controller is connected to the DC bus via the bidirectional DC-to-DC module, and the energy storage battery is connected to the second end of the first photovoltaic controller; the installed capacity of the photovoltaic and storage module is n times the load power, where n is a natural number greater than or equal to 0.8; the stacked photovoltaic module converts light energy into electrical energy and provides it to the DC bus; the installed capacity of the stacked photovoltaic module is 0.8 to 1.2 times the load power; the AC-to-DC module converts AC power provided by the power grid into DC power and provides it to the DC bus. The present invention limits the capacity of the battery in advance by predicting the SOC, and then discharges the battery multiple times, while satisfying the peak shaving and valley filling function, and further adjusts the battery capacity by using the photovoltaic prediction function, to ensure that photovoltaic power generation is fully utilized, greatly reduce the occurrence of abandoned light, and improve the utilization rate of photovoltaic power generation. By combining DC photovoltaic with energy storage, the excess electrical energy generated by photovoltaics is stored in energy storage batteries and utilized, so as to reduce bus voltage fluctuations, avoid photovoltaic abandoned light, and improve photovoltaic power generation efficiency and system reliability. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0112] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A photovoltaic storage system, characterized in that: The integrated optical storage system comprises: The optical storage module, the stacked optical module and the AC-DC converter module are connected in parallel to the DC bus; The photovoltaic storage module includes at least one group of photovoltaic storage units, each photovoltaic storage unit includes a first photovoltaic panel, a first photovoltaic controller, an energy storage battery and a bidirectional DC-DC module, wherein the first photovoltaic panel is connected to the first end of the first photovoltaic controller, the second end of the first photovoltaic controller is connected to the DC bus via the bidirectional DC-DC module, and the energy storage battery is connected to the second end of the first photovoltaic controller; the installed capacity of the photovoltaic storage module is n times the load power, where n is a number greater than or equal to 0.8; The stacked light module converts light energy into electrical energy and provides it to the DC bus; the installed capacity of the stacked light module is 0.8 to 1.2 times the load power; The AC-DC module converts AC power provided by the power grid into DC power, and provides the DC power to the DC bus.

2. The integrated photovoltaic and storage system according to claim 1, characterized in that: The stacked light module includes at least one group of stacked light units, each of which includes a second photovoltaic panel and a second photovoltaic controller, and the second photovoltaic panel is connected to the DC bus via the second photovoltaic controller.

3. An energy control method, implemented based on the photovoltaic energy storage system according to any one of claims 1-2, characterized in that: The energy control method at least comprises: In the first power demand period, the power grid supplies power to the load on the DC bus, and based on the bidirectional DC conversion module, the power on the power grid is stored in the energy storage battery, and the charging amount of the energy storage battery is determined by the power generated in the previous photovoltaic power generation cycle; In the second power demand period, the stacked light module and the light storage module supply power to the load, the photovoltaic multi-generation energy in the light storage module is stored in the energy storage battery, and the working state of the energy storage battery is dynamically adjusted according to the photovoltaic power generation based on the bidirectional DC conversion module, and the priority of the stacked light module is higher than that of the light storage module; In the third power demand period, the stacked optical module, the optical storage module and the power grid supply power to the load, and the priorities of the stacked optical module, the optical storage module and the power grid decrease in sequence; Among them, the first power demand period, the second power demand period and the third power demand period are arranged in a cycle in sequence; the first power demand period is a trough period, the second power demand period is a flat period, and the third power demand period is a peak period and / or a spike period.

4. The energy control method according to claim 3, characterized in that: In the first power demand period, a predicted SOC of the energy storage battery is obtained based on the photovoltaic power generation and load power consumption in the previous photovoltaic power generation cycle, and charging of the energy storage battery is stopped when the energy storage battery is charged to the predicted SOC.

5. The energy control method according to claim 4, characterized in that: The predicted SOC is the ratio of the difference between the battery nominal capacity and the amount of electricity provided to the energy storage battery by photovoltaic power generation in the previous photovoltaic power generation cycle to the battery nominal capacity.

6. The energy control method according to claim 3, characterized in that: In the starting period of the second power demand period, controlling the energy storage battery to discharge based on the bidirectional DC conversion module; In the middle period of the second power demand period, judging whether the energy storage battery is discharged according to the relationship between the average photovoltaic power generation power and the load power of the day; At the end of the second power demand period, the energy storage battery is controlled to be fully charged based on the bidirectional DC conversion module.

7. The energy control method according to claim 3, characterized in that: When a third power demand period is provided between the first power demand period and the second power demand period, In the starting period and the middle period of the second power demand period, judging whether the energy storage battery is discharged according to the relationship between the average photovoltaic power generation power and the load power of the day; At the end of the second power demand period, the energy storage battery is controlled to be fully charged based on the bidirectional DC conversion module.

8. The energy control method according to claim 6 or 7, characterized in that: The start time period is set to 1 hour to 4 hours, and the end time period is set to 1 hour to 4 hours.

9. The energy control method according to claim 6 or 7, characterized in that: In the starting period and the middle period of the second power demand period, the method for determining whether the energy storage battery is discharged includes: if P PVaver ≥K1*P Load , the energy storage battery discharges; otherwise, the energy storage battery does not discharge; Among them, P PVaver is the average photovoltaic power generation of the day; K1 is the discharge judgment coefficient, K1∈[0.5,2]; P Load is the load power of the day.

10. The energy control method according to claim 6 or 7, characterized in that: When the middle period of the second power demand period is embedded in the first power demand period, during the first power demand period embedded in the second power demand period, the working state of the energy storage battery is judged according to the relationship between the average photovoltaic power generation power and the load power of the day.

11. The energy control method according to claim 10, characterized in that: In the first power demand period embedded in the second power demand period, if P PVaver ≥K1*P Load , then the energy storage battery is controlled to discharge based on the bidirectional DC conversion module; if P PVaver <K2*P Load , then controlling the charging of the energy storage battery based on the bidirectional DC conversion module; Otherwise, the bidirectional DC conversion module does not work; Among them, P PVaver is the average photovoltaic power generation power of the day; P Load is the load power of the day; K1 is the discharge judgment coefficient, K1∈[0.5,2]; K2 is the charge judgment coefficient, K2∈(0,0.5].

12. The energy control method according to claim 6 or 7, characterized in that: When a second power demand period is provided between the third power demand period and the first power demand period, the energy storage battery is discharged to a set SOC in the second power demand period between the third power demand period and the first power demand period, and the set SOC is not greater than 30%.

13. The energy control method according to any one of claims 3 to 7, characterized in that: When charging the energy storage battery, the bidirectional DC-to-DC module controls the voltage of the energy storage battery, and the maximum limit value of the voltage loop output is set to positive, and the minimum limit value is set to negative; when discharging the energy storage battery, the bidirectional DC-to-DC module controls the DC bus voltage, and the control voltage target value is greater than the output voltage value of the AC-to-DC module, the maximum limit value of the voltage loop output is set to negative, and the minimum limit value is set to negative.

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