Output Smoothing System and Method for Photovoltaic Energy Storage System

Abstract

The present invention provides an output smoothing system and method for a photovoltaic energy storage system, wherein the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system. The method includes: determining, by a coarse adjustment module, a coarse adjustment power value of the energy storage system according to a set coarse adjustment value calculation method, so as to improve the response speed of the energy storage system for smoothing the total output power of the photovoltaic energy storage system; and determining, by a fine adjustment module, a fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, using a fine adjustment value control algorithm, so as to improve the accuracy of the energy storage system for smoothing the total output power of the photovoltaic energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical fields of smart grid and energy storage and conversion, and particularly relates to a system and method for smoothing the output of a photovoltaic energy storage system. Background Art

[0002] Due to the characteristics of uncertainty and instability of photovoltaic power generation, etc., the instantaneous rise or fall of the power generated by photovoltaic power generation will cause the output power to be unstable, making the grid-connected power of photovoltaic power generation fluctuate continuously. Moreover, as the proportion of photovoltaic power generation in the power grid increases continuously, the smooth control of the output power of solar power generation has received increasing attention.

[0003] With the continuous development of battery and its integration technology, it has gradually become a feasible solution to use a battery energy storage power station to smooth the output of solar power generation. By reasonably controlling the converter connected to the energy storage device and efficiently realizing the charge and discharge of the energy storage system, the problem of unstable output power of photovoltaic power generation caused by the randomness, intermittency and volatility of photovoltaic power generation, etc., can be solved to a great extent, so as to meet the requirement of smooth output of solar power generation and effectively solve the problems of power quality, etc. caused by the fluctuation of photovoltaic power generation to the power grid frequency fluctuation. The photovoltaic energy storage combined power generation system is essentially a multi-energy system. How to coordinate the work of each power supply system is a key problem in the research and development of multi-energy hybrid power generation systems. In addition, during the smoothing process, it is not easy to achieve fast and accurate compensation. Summary of the Invention

[0004] The purpose of the present invention is to provide a system and method for smoothing the output of a photovoltaic energy storage system, so as to solve the problem that the existing photovoltaic energy storage system cannot compensate both quickly and accurately during the smoothing process.

[0005] The purpose of the present invention is also to provide a system and method for smoothing the output of a photovoltaic energy storage system, so as to solve the problem of how to coordinate the work of each power supply system in the photovoltaic energy storage system.

[0006] To solve the above technical problems, the present invention provides a method for smoothing the output of a photovoltaic energy storage system,

[0007] wherein the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system, and the method includes:

[0008] The coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the set coarse adjustment value calculation method, so as to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system;

[0009] The fine adjustment module determines the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, and uses the fine adjustment value control algorithm, so as to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

[0010] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, the coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the set coarse adjustment value calculation method, including:

[0011] Determining a set value of the coarse adjustment fluctuation control range according to the maximum allowable fluctuation ratio in each application scenario; and

[0012] Determining the coarse adjustment power value of the energy storage system, where the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and the set value of the coarse adjustment fluctuation control range.

[0013] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, the fine adjustment module calculates according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, including:

[0014] Determining the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; and

[0015] Processing the difference through a first-order filtering algorithm to obtain the fine adjustment power value.

[0016] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: the total output power of the photovoltaic energy storage system is obtained through the following formula:

[0017]

[0018] Where:

[0019] P bess_real Is the output power of the energy storage system;

[0020] P ne_pre Is the predicted power of the photovoltaic power generation system;

[0021] P ne_real Is the real-time power of the photovoltaic power generation system;

[0022] P out_real Is the total output power of the photovoltaic energy storage system;

[0023] k set Is the set value of the coarse adjustment fluctuation control range;

[0024] T is the time constant. The larger the value of T, the smaller the differential power result and the better the smoothing effect.

[0025] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes:

[0026] The real-time acquisition system acquires the current state and the current state of charge of the energy storage system. The current state includes the normal state, the abnormal state, and the fault state; and

[0027] The real-time acquisition system acquires the real-time power of the photovoltaic power generation system.

[0028] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: processing according to the current state of the energy storage system acquired by the real-time acquisition system, and performing it in real-time loop;

[0029] If the current state is the normal state, enter the allowable smoothing compensation mode;

[0030] If the current state is the abnormal state, enter the pause and repair mode;

[0031] If the current state is the fault state, enter the prohibited smoothing compensation mode.

[0032] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: The prohibited smoothing compensation mode includes:

[0033] The energy storage system does not output power, and the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation;

[0034] The fault state includes battery system faults of the energy storage system, PCS faults of the energy storage converter, serious faults of the energy storage environmental control system, fire protection system faults, etc. These faults will cause the energy storage system to be unable to work or affect the safe and stable operation of the energy storage system.

[0035] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: The allowable smoothing compensation mode includes:

[0036] The photovoltaic power prediction platform outputs the predicted power of the photovoltaic power generation within the current time period;

[0037] The real-time acquisition system outputs the real-time power of the photovoltaic power generation;

[0038] The coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the predicted power to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system;

[0039] The fine adjustment module determines the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, using the fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system;

[0040] Based on the coarse adjustment power value and the fine adjustment power value, calculate the output power of the energy storage system in real-time. If the calculated output power is positive, the energy storage system discharges; if the calculated output power is negative, charge the energy storage system.

[0041] Optionally, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: judging whether the energy storage system has charging conditions or discharging conditions according to the calculated output power and the current state of charge collected by the real-time acquisition system, where:

[0042] If the output power is positive and the current state of charge is less than the low threshold, there is no discharging condition;

[0043] If the output power is negative and the current state of charge is greater than the high threshold, there is no charging condition;

[0044] Otherwise, the energy storage system has charging conditions and discharging conditions, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system constitute the total output power at the grid connection point;

[0045] When the energy storage system does not have charging conditions or discharging conditions, the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation;

[0046] Under the condition that the current state of charge is greater than the third threshold, the energy storage system discharges according to the value of the current state of charge.

[0047] The present invention also provides a system for smoothing the output of a photovoltaic energy storage system. The photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system, and includes:

[0048] A coarse adjustment module configured to determine the coarse adjustment power value of the energy storage system according to a set coarse adjustment value calculation method to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system;

[0049] A fine adjustment module configured to determine the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, and use a fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

[0050] The inventor of the present invention has found through research that in the prior art, there are methods for determining the optimal configuration of the energy storage system capacity through clear smoothing methods, with the focus on optimizing the configuration of the energy storage capacity; and using historical power generation data of photovoltaic power generation to fit an ideal smooth output curve, and then using the magnitude relationship between the actual output of photovoltaic power generation and the ideal smooth output to determine the output of the energy storage, with the focus on determining the output calculation of the energy storage; and proposing a method for smoothing the output of the energy storage system for the purpose of smoothing photovoltaic power generation, where the state of charge of the energy storage system is maintained at an appropriate level, improving the continuous charge and discharge capacity of the energy storage system, and realizing the coordinated optimization of the smoothing ability and performance indicators of the energy storage system, with the focus on the control of the energy storage system. None of the above prior arts have paid attention to the overall control process of the photovoltaic system and the relationship between the energy storage system and the ultra-short-term power generation prediction data of the photovoltaic system.

[0051] In the output smoothing system and method of the photovoltaic energy storage system provided by the present invention, the support power (which can be positive or negative) required for the energy storage system to smooth the real-time power of the photovoltaic power generation system is calculated as the coarse adjustment power value; the difference between the predicted value of the power output of the photovoltaic power generation system and the actual output power of the photovoltaic power generation system is introduced into a control algorithm (fine adjustment value control algorithm) for fine adjustment, and the calculation result is used as the fine adjustment power value. By combining the "coarse adjustment" and "fine adjustment" methods, it is possible to meet the requirements of faster response and more precise control for photovoltaic energy storage smoothing control.

[0052] Based on the ultra-short-term photovoltaic power generation prediction data, under the premise of taking the current state and the current state of charge of the energy storage system as constraints, the present invention processes the current state of the energy storage system collected by the real-time acquisition system, and determines whether the energy storage system has the conditions for charging or discharging, thus realizing the coordinated control between parts of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the structure of the output smoothing system of the photovoltaic energy storage system and the relationship between various parameters in an embodiment of the present invention;

[0054] Figure 2 It is a schematic diagram of the flow of the output smoothing method of the photovoltaic energy storage system in an embodiment of the present invention;

[0055] Figure 3 It is a schematic diagram of the control block diagram for calculating the total output power in the output smoothing method of the photovoltaic energy storage system in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The present invention will be further described below in conjunction with the detailed description with reference to the drawings.

[0057] It should be noted that the components in the drawings may be exaggerated for illustration purposes and are not necessarily to scale. In each drawing, the same or functionally identical components are provided with the same reference numerals.

[0058] In the present invention, unless otherwise specified, "arranged on...", "arranged above...", and "arranged on top of..." do not exclude the existence of intermediate objects between the two. In addition, "arranged on or above..." only represents the relative position relationship between two components, and in certain cases, such as when the product direction is reversed, it can also be converted to "arranged under or below...", and vice versa.

[0059] In the present invention, each embodiment is only intended to illustrate the solution of the present invention and should not be construed as restrictive.

[0060] In the present invention, unless otherwise specified, the quantifiers "a" and "one" do not exclude the scenario of multiple elements.

[0061] It should also be noted here that in the embodiments of the present invention, for the sake of clarity and simplicity, only a part of the components or assemblies may be shown. However, those of ordinary skill in the art can understand that, under the teaching of the present invention, the required components or assemblies can be added according to the specific scenario requirements. Additionally, unless otherwise stated, the features in different embodiments of the present invention can be combined with each other. For example, a certain feature in the second embodiment can be used to replace the corresponding or functionally identical or similar feature in the first embodiment, and the resulting embodiment also falls within the scope of disclosure or the scope of recording of this application.

[0062] It should also be noted here that within the scope of the present invention, the terms "identical", "equal", "equal to", etc. do not mean that the two values are absolutely equal, but allow a certain reasonable error. That is to say, these terms also cover "substantially identical", "substantially equal", "substantially equal to". By analogy, in the present invention, the directional terms "perpendicular to", "parallel to", etc. also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0063] In addition, the numbering of the steps of the various methods of the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps can be executed in different orders.

[0064] The following further elaborates in detail on the output smoothing system and method of the photovoltaic energy storage system proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description and the claims, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention.

[0065] The purpose of the present invention is to provide an output smoothing system and method for a photovoltaic energy storage system to solve the problem that the existing photovoltaic energy storage system cannot compensate quickly and accurately during the smoothing process.

[0066] The purpose of the present invention is also to provide an output smoothing system and method for a photovoltaic energy storage system to solve the problem of how the photovoltaic energy storage system coordinates the work of each power supply system.

[0067] To achieve the above object, the present invention provides a system and method for smoothing the output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system. The method includes: a coarse adjustment module determines a coarse adjustment power value of the energy storage system according to a set coarse adjustment value calculation method to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system; a fine adjustment module determines a fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system by using a fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

[0068] An embodiment of the present invention provides a method for smoothing the output of a photovoltaic energy storage system, as Figure 1 shown, the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system 30. The method includes: a coarse adjustment module 10 determines a coarse adjustment power value of the energy storage system 30 according to a set coarse adjustment value calculation method to improve the response speed of the energy storage system 30 to smooth the total output power of the photovoltaic energy storage system; a fine adjustment module 20 determines a fine adjustment power value of the energy storage system 30 according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system by using a fine adjustment value control algorithm to improve the accuracy of the energy storage system 30 to smooth the total output power of the photovoltaic energy storage system.

[0069] In an embodiment of the present invention, as Figure 1 、 3 shown, in the method for smoothing the output of the photovoltaic energy storage system, the coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the set coarse adjustment value calculation method, including: the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and the set value of the coarse adjustment fluctuation control range; the value of the coarse adjustment fluctuation control range is based on the maximum fluctuation ratio allowed in each application scenario (set by local power companies).

[0070] In an embodiment of the present invention, as Figure 1 、 3 shown, in the method for smoothing the output of the photovoltaic energy storage system, the fine adjustment module determines the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system by using a fine adjustment value control algorithm, including: determining the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; performing a first-order filtering algorithm on the difference to obtain the fine adjustment power value.

[0071] In an embodiment of the present invention, the coarse adjustment obtains the coarse adjustment value according to the smoothing fluctuation control within a certain range, calculates the fine adjustment value by using a first-order filter, and after passing the battery SOC verification, combines the photovoltaic power generation output and then outputs. As Figure 3As shown, in the output power smoothing method of the photovoltaic energy storage system, it further includes: the total output power of the photovoltaic energy storage system is obtained through the following formula:

[0072]

[0073] Where:

[0074] P bess_real is the output power of the energy storage system;

[0075] P ne_pre is the predicted power of the photovoltaic power generation system;

[0076] P ne_real is the real-time power of the photovoltaic power generation system;

[0077] P out_real is the total output power of the photovoltaic energy storage system;

[0078] k set is the set value of the coarse adjustment fluctuation control range;

[0079] T is the time constant. The larger the value of T, the smaller the differential power result and the better the smoothing effect.

[0080] As Figure 2 shown, in the output power smoothing method of the photovoltaic energy storage system, it further includes: the real-time acquisition system acquires the current state and the current state of charge of the energy storage system, and the current state includes the normal state, the abnormal state, and the fault state; and the real-time acquisition system acquires the real-time power of the photovoltaic power generation system.

[0081] In an embodiment of the present invention, in the output power smoothing method of the photovoltaic energy storage system, it further includes: processing according to the current state of the energy storage system acquired by the real-time acquisition system (such as Figure 2 the step of judging whether the energy storage system is normal shown), and performing it in real-time loop; if the current state is the normal state (yes), then enter the allowable smoothing compensation mode; if the current state is the abnormal state, then enter the pause and repair mode; if the current state is the fault state (no), then enter the prohibited smoothing compensation mode.

[0082] In an embodiment of the present invention, in the output power smoothing method of the photovoltaic energy storage system, it further includes: the prohibited smoothing compensation mode includes: the energy storage system does not output power, and the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation (jumping to the end step as Figure 2 shown); the fault state includes battery system failure of the energy storage system, PCS failure of the energy storage converter, serious failure of the energy storage environmental control system, fire protection system failure, etc., and these failures will cause the energy storage system to fail to work or affect the safe and stable operation of the energy storage system.

[0083] In one embodiment of the present invention, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: The allowable smoothing compensation mode includes: As Figure 2 shown, the photovoltaic power generation prediction platform outputs the predicted power of the photovoltaic power generation within the current period (such as the step of obtaining ultra-short-term prediction data of the optical power as Figure 2 shown); The real-time power of the photovoltaic power generation output by the real-time acquisition system is collected (such as the step of sampling to obtain the actual output of the photovoltaic as Figure 2 shown); As Figure 1 、 3 shown, the coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the predicted power to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system (such as the step of calculating the coarse adjustment value of the energy storage output as Figure 2 shown); As Figure 1 、 3 shown, the fine adjustment module uses the fine adjustment value control algorithm to determine the fine adjustment power value of the energy storage system according to the difference between the real-time power and the predicted power of the photovoltaic power generation system to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system (such as the step of calculating the fine adjustment value of the energy storage output as Figure 2 shown); As Figures 1 - 3 shown, based on the coarse adjustment power value and the fine adjustment power value, the output power of the energy storage system is calculated in real time (such as the step of calculating the output value of the energy storage system as Figure 2 shown). If the calculated output power is positive, the energy storage system discharges; if the calculated output power is negative, the energy storage system is charged.

[0084] From the perspective of the battery, excessive charging and excessive discharging will both affect the battery life. Therefore, it is necessary to monitor the state of charge (SOC) of the battery and control the state of charge of the battery within a certain range. Moreover, in the photovoltaic and energy storage combined power generation system, if there is no reasonable and effective control strategy to monitor the remaining state of charge of the energy storage battery, it will increase unnecessary battery capacity and usage costs.

[0085] Based on the above insights, in one embodiment of the present invention, in the method for smoothing the output of the photovoltaic energy storage system, it further includes: According to the calculated output power and the current state of charge collected by the real-time acquisition system, it is judged whether the energy storage system has the charging condition or the discharging condition (such as the step of judging whether the energy storage SOC is satisfied as Figure 2 shown), where: If the output power is positive and the current state of charge is less than the low threshold, the discharging condition is not available; if the output power is negative and the current state of charge is greater than the high threshold, the charging condition is not available; otherwise, the energy storage system has the charging condition and the discharging condition, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system constitute the total output power at the grid connection point (such as Figure 2The steps of calculating the combined output value of photovoltaic and energy storage are shown); when the energy storage system does not have the charging condition or the discharging condition, the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation (jump to as Figure 2 shown in the end steps); under the condition that the current state of charge is greater than the third threshold, the energy storage system discharges according to the value of the current state of charge.

[0086] The present invention also provides a system for smoothing the output of a photovoltaic energy storage system, as Figure 1 shown, the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system 30, including: a coarse adjustment module 10, configured to determine the coarse adjustment power value of the energy storage system 30 according to a set coarse adjustment value calculation method, so as to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system; a fine adjustment module 20, configured to determine the fine adjustment power value of the energy storage system 30 according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, using a fine adjustment value control algorithm, so as to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

[0087] The present invention not only focuses on the overall control process of the photovoltaic system, but also controls according to the relationship between the energy storage system and the ultra-short-term power generation prediction data of the photovoltaic system.

[0088] In the system and method for smoothing the output of a photovoltaic energy storage system provided by the present invention, the support power (which can be positive or negative) required for the energy storage system to smooth the real-time power of the photovoltaic power generation system is calculated as the coarse adjustment power value; the difference between the predicted value of the power output of the photovoltaic power generation system and the actual output power of the photovoltaic power generation system is introduced into a control algorithm (fine adjustment value control algorithm) for fine adjustment, and the calculation result is used as the fine adjustment power value, realizing a method of combining "coarse adjustment" and "fine adjustment", which can meet the requirements of faster response and more accurate control for photovoltaic energy storage smoothing control.

[0089] The present invention, based on the ultra-short-term power generation prediction data of the photovoltaic system, under the premise of taking the current state and the current state of charge of the energy storage system as constraints, processes according to the current state of the energy storage system collected by the real-time acquisition system, and judges whether the energy storage system has the charging condition or the discharging condition, realizing the collaborative output smoothing among the parts of the whole system.

[0090] A method for smoothing the output of a photovoltaic energy storage based on ultra-short-term photovoltaic power prediction data, the core of which includes using a method of combining "coarse adjustment" and "fine adjustment". Under the condition that the smoothing target is determined, the preliminary adjustment output value is quickly determined by "coarse adjustment", and then according to the difference between the real-time output of the photovoltaic power generation system and the ultra-short-term prediction data, it is "fine-adjusted" and corrected through a control algorithm (first-order filtering, PID, etc.), thereby ensuring the control accuracy.

[0091] Based on the ultra-short-term photovoltaic power prediction data, the present invention can calculate the rough adjustment value of the energy storage output in advance, with a fast rough adjustment speed, thus shortening the overall response time; the difference between the actual output power and the predicted value of photovoltaic power generation is used as the fine adjustment value, and a control algorithm is introduced for fine adjustment, thereby improving the overall adjustment accuracy; the method of combining rough adjustment and fine adjustment is used to make the energy storage system for smoothing the photovoltaic power output have a faster response speed and higher accuracy.

[0092] In summary, the above embodiments have described in detail the different configurations of the output smoothing system and method of the photovoltaic energy storage system. Of course, the present invention includes but is not limited to the configurations listed in the above embodiments. Any content transformed on the basis of the configurations provided in the above embodiments belongs to the scope protected by the present invention. Those skilled in the art can draw inferences from one instance to another based on the content of the above embodiments.

[0093] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. For the system disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part.

[0094] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure belong to the scope protected by the claims.

Claims

1. A method for smoothing the output of a photovoltaic energy storage system, wherein the photovoltaic energy storage system includes a photovoltaic power generation system and an energy storage system, characterized in that, the method includes: The coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the set coarse adjustment value calculation method to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system. Wherein, the coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the set coarse adjustment value calculation method, including: Determining the set value of the coarse adjustment fluctuation control range according to the maximum allowable fluctuation ratio in each application scenario; and Determining the coarse adjustment power value of the energy storage system, where the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and the set value of the coarse adjustment fluctuation control range; and The fine adjustment module determines the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, using the fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

2. The method for smoothing the output of a photovoltaic energy storage system according to claim 1, characterized in that, The fine adjustment module determines the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, including: Determining the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system; and Processing the difference through a first-order filtering algorithm to obtain the fine adjustment power value.

3. The method for smoothing the output of a photovoltaic energy storage system according to claim 1, characterized in that, further includes: The total output power of the photovoltaic energy storage system is obtained through the following formula: Where: is the output power of the energy storage system; is the predicted power of the photovoltaic power generation system; is the real-time power of the photovoltaic power generation system; is the total output power of the photovoltaic energy storage system; Set value for rough adjustment fluctuation control range; is the time constant. The larger the value of T, the smaller the differential power result and the better the smoothing effect.

4. The method for smoothing the output of a photovoltaic energy storage system according to claim 1, characterized in that, further includes: The real-time acquisition system collects the current state and the current state of charge of the energy storage system. The current state includes the normal state, the abnormal state and the fault state; and The real-time acquisition system collects the real-time power of the photovoltaic power generation system.

5. The method for smoothing the output of a photovoltaic energy storage system according to claim 4, characterized in that, further includes: Processing according to the current state of the energy storage system collected by the real-time acquisition system, and performing it in real-time loop; If the current state is the normal state, enter the allowable smoothing compensation mode; If the current state is the abnormal state, enter the pause and repair mode; If the current state is the fault state, enter the prohibited smoothing compensation mode.

6. The method for smoothing the output of a photovoltaic energy storage system according to claim 5, characterized in that, further includes: The prohibited smoothing compensation mode includes: The energy storage system does not output power, and the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation; The fault state includes battery system fault of the energy storage system, PCS fault of the energy storage converter, serious fault of the energy storage environmental control system, and fire protection system fault.

7. The method for smoothing the output of a photovoltaic energy storage system according to claim 5, characterized in that, further includes: The allowable smoothing compensation mode includes: The photovoltaic power prediction platform outputs the predicted power of the photovoltaic power generation within the current time period; The real-time acquisition system outputs the real-time power of the photovoltaic power generation; The coarse adjustment module determines the coarse adjustment power value of the energy storage system according to the predicted power, so as to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system; The fine adjustment module determines the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, and uses the fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system; Based on the coarse adjustment power value and the fine adjustment power value, the output power of the energy storage system is calculated in real time. If the calculated output power is positive, the energy storage system discharges; if the calculated output power is negative, the energy storage system is charged.

8. The method for smoothing the output of a photovoltaic energy storage system according to claim 7, characterized in that, further comprising: judging whether the energy storage system has the charging condition or the discharging condition according to the calculated output power and the current state of charge collected by the real-time acquisition system, wherein: if the output power is positive and the current state of charge is less than the low threshold, the discharging condition is not met; if the output power is negative and the current state of charge is greater than the high threshold, the charging condition is not met; otherwise, the energy storage system has the charging condition and the discharging condition, and the real-time power of the photovoltaic power generation system and the output power of the energy storage system constitute the total output power at the grid connection point; when the energy storage system does not have the charging condition or the discharging condition, the grid connection point of the photovoltaic power generation system directly outputs the real-time power of the photovoltaic power generation.

9. An output smoothing system for a photovoltaic energy storage system, the photovoltaic energy storage system comprising a photovoltaic power generation system and an energy storage system, characterized in that, comprising: a coarse adjustment module configured to determine the coarse adjustment power value of the energy storage system according to a set coarse adjustment value calculation method, so as to improve the response speed of the energy storage system to smooth the total output power of the photovoltaic energy storage system, wherein determining the coarse adjustment power value of the energy storage system by the coarse adjustment module according to the set coarse adjustment value calculation method includes: determining a coarse adjustment fluctuation control range setting value according to the maximum allowable fluctuation ratio in each application scenario; and determining the coarse adjustment power value of the energy storage system, wherein the coarse adjustment power value of the energy storage system is equal to the product of the predicted power of the photovoltaic power generation system and the coarse adjustment fluctuation control range setting value; and a fine adjustment module configured to determine the fine adjustment power value of the energy storage system according to the difference between the real-time power of the photovoltaic power generation system and the predicted power of the photovoltaic power generation system, and use the fine adjustment value control algorithm to improve the accuracy of the energy storage system to smooth the total output power of the photovoltaic energy storage system.

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