A method and system for operating a photovoltaic-battery system

Abstract

The application discloses a photovoltaic-battery system operation control method and system, comprising: real-time monitoring of user load power, battery real-time power and photovoltaic total power generation power data; taking the difference between the sum of the user load power and the battery real-time power and the photovoltaic total power generation power as a real-time power difference; when the system is normally operated, when the real-time power difference is greater than or equal to a set value M, the battery is controlled to be discharged; when the real-time power difference is less than or equal to a set value N, the battery is controlled to be charged; when the real-time power difference is between the set values M and N, the battery is neither charged nor discharged. The application does not need photovoltaic and load prediction data, and the patent can dynamically adjust photovoltaic power generation power, battery charging / discharging power in real time according to photovoltaic operation data, user load data and battery operation data.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic power generation technology, and particularly relates to a photovoltaic-battery system operation control method and system. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] A new power system mainly based on new energy is gradually established, and locations such as roofs and carports have become places for arranging distributed photovoltaic power generation, and parks have become the main application scenarios of distributed photovoltaic power stations.

[0004] Distributed photovoltaic grid connection has access permission, and when a distributed photovoltaic system is connected to the grid at a voltage level of 380V, the cost of grid-related equipment can be almost negligible; when the photovoltaic installed capacity is large (such as an installed capacity of about 2-3MW), many parks have been unable to connect to the grid at a voltage level of 380V (the original transformer capacity and quantity cannot accommodate the photovoltaic capacity), and need to be connected to the grid at 10KV; at this time, relevant grid-related equipment needs to be installed according to relevant specifications and requirements, and the grid-related equipment required for photovoltaic installed capacity of about 2-3MW is the same as that required for installed capacity of about 5-6MW, but the cost of the latter can be distributed to a larger photovoltaic capacity, making the cost of the photovoltaic power station per unit of power lower, and relatively, the cost of the former is higher, and the investment income cannot meet the requirements of project construction.

[0005] Therefore, considering the economy, a distributed photovoltaic system of about 2-3MW needs to be set up with reverse power protection equipment at the grid connection point on the premise of containing necessary energy storage, and the photovoltaic system must be immediately turned off in case of reverse power grid connection, and the photovoltaic system restarts power generation when power consumption is greater than photovoltaic power generation. This frequent start-stop operation mode avoids the occurrence of reverse power grid connection, but reduces the power generation time of the photovoltaic system and also adversely affects the service life of the equipment.

[0006] At present, energy management equipment can realize the fluctuation of photovoltaic maximum power generation with load and avoid the occurrence of reverse power grid connection by real-time monitoring of photovoltaic and load data, but the equipment does not consider the operation of the battery equipment in the photovoltaic system.

[0007] In addition, although the operation of the photovoltaic system can be controlled by optimizing scheduling, the optimization scheduling of the photovoltaic-battery needs the prediction results of photovoltaic and load, and the prediction accuracy of photovoltaic and load is gradually improved with the accumulation of operation data, and it is difficult to put into operation in the early stage of project operation. SUMMARY

[0008] In order to solve the above problems, the application provides a photovoltaic-battery system operation control method and system, based on the operation principle of "surplus electricity not on the network", in the case of lacking prediction data, based on user load data, realizing efficient operation of photovoltaic and battery, avoiding frequent start and stop of photovoltaic system.

[0009] In some embodiments, the following technical solutions are adopted:

[0010] A photovoltaic-battery system operation control method, comprising:

[0011] Real-time monitoring of user load power, real-time battery power and total photovoltaic power generation power data;

[0012] The difference between the sum of user load power and real-time battery power and total photovoltaic power generation power is taken as real-time power difference;

[0013] When the real-time power difference is greater than or equal to the set value M, the battery is discharged; when the real-time power difference is less than or equal to the set value N, the battery is charged; when the real-time power difference is between the set values M and N, the battery is neither charged nor discharged.

[0014] As a further scheme, the battery charging power adopts step change, specifically:

[0015] q6=μ3*(Q-q)+4*

[0016] Wherein, q6 is the battery charging power, μ3 is the charging process battery capacity influence factor, μ4 is the charging process power difference influence factor, Q is the rated capacity of the battery, q is the current capacity of the battery, and c is the charging power difference coefficient of the battery;

[0017] The value of c changes in steps, and the value of c is specifically:

[0018] When ,

[0019] When ,

[0020] When ,

[0021] When ,

[0022] When ,

[0023] Wherein, a is the safety margin, q1 is the total photovoltaic power generation, q2 is the user load power, and q3 is the real-time power monitoring value of the battery.

[0024] As a further place, the battery discharge power adopts a step change, specifically:

[0025] q5 = μ1 * q + μ2 * d

[0026] Wherein, μ1 is the battery capacity influence factor in the discharge process, μ2 is the power difference influence factor in the discharge process, q is the current capacity of the battery, and d is the discharge power difference coefficient;

[0027] The value of d is a step change, and the value of d is specifically:

[0028] When ,

[0029] When ,

[0030] When ,

[0031] When ,

[0032] When , d = (N-a);

[0033] Wherein, a is the safety margin, q1 is the total photovoltaic power generation, q2 is the user load power, and q3 is the real-time power monitoring value of the battery.

[0034] As a further place, when the real-time power difference is less than the safety margin a, the battery is charged at the maximum power.

[0035] As a further place, the method further comprises:

[0036] When the photovoltaic reverse power protection is triggered, the battery discharge or charge state is stopped; the current power load C1 and the normal operation photovoltaic quantity H1 are obtained;

[0037] Determine whether the current power load C1 satisfies C1≥a, if so, restart the photovoltaic system, and set the single photovoltaic power upper limit as: (C1-a) / H1;

[0038] After the photovoltaic system reaches the expected power, the photovoltaic system and the battery enter the normal operation state.

[0039] As a further place, the method further comprises:

[0040] When a high-power device is shut down, assuming that the device electrical load is R, if R >= a, stop the battery discharge or charging state; obtain the current power consumption load C2 and the normal operation of the photovoltaic quantity H2;

[0041] The upper limit of the single photovoltaic power is set as (C2-a) / H2, and after the photovoltaic system reaches the expected power, the photovoltaic system and the battery enter the normal operation state.

[0042] As a further place, the photovoltaic total power is charged to the battery, and the reduced photovoltaic power is used as the upper limit of the photovoltaic power, and the upper limit of the photovoltaic power fluctuates with the power consumption load.

[0043] In some other embodiments, the following technical solutions are adopted:

[0044] A photovoltaic-battery system operation control system comprises:

[0045] A data acquisition module is used to monitor the user load power, the real-time power of the battery and the total photovoltaic power generation data in real time; the difference between the sum of the user load power and the real-time power of the battery and the total photovoltaic power generation is used as the real-time power difference.

[0046] A battery charge and discharge control module is used to control the battery to discharge when the real-time power difference is greater than or equal to a set value M when the system is in normal operation; control the battery to charge when the real-time power difference is less than or equal to a set value N; and the battery is neither charged nor discharged when the real-time power difference is between the set values M and N.

[0047] In some other embodiments, the following technical solutions are adopted:

[0048] A terminal device comprises a processor and a memory, the processor is used to implement instructions; the memory is used to store a plurality of instructions, the instructions are suitable for being loaded and executed by the processor to implement the photovoltaic-battery system operation control method.

[0049] In some other embodiments, the following technical solutions are adopted:

[0050] A computer readable storage medium, wherein a plurality of instructions are stored, the instructions are suitable for being loaded and executed by the processor of the terminal device to implement the photovoltaic-battery system operation control method.

[0051] Compared with the prior art, the beneficial effects of the present application are:

[0052] (1) The present application does not require photovoltaic and load prediction data, and the patent can dynamically adjust the photovoltaic power generation, the battery charge / discharge power in real time according to the photovoltaic operation data, the user load data and the battery operation data.

[0053] (2) The charging and discharging power of the battery in this invention adopts a stepped change to avoid frequent changes in battery power. The charging power of the battery is established as a function relationship with two dependent variables, namely the remaining capacity of the battery and the real-time power difference, so as to realize the dynamic adjustment of the charging power; the discharging power is established as a function relationship with two dependent variables, namely the remaining capacity of the battery and the real-time power difference, so as to realize the dynamic adjustment of the discharging power.

[0054] Other features and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0055] Figure 1 This is a flowchart of the photovoltaic-battery system operation control method in an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the reverse power protection process in an embodiment of the present invention;

[0057] Figure 3 This is a schematic diagram of the equipment shutdown control process in an embodiment of the present invention. Detailed Implementation

[0058] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0059] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0060] Example 1

[0061] In one or more embodiments, a photovoltaic-battery system operation control method is disclosed. Based on the photovoltaic power station equipment operation data, battery operation data, and power load data, the photovoltaic power station power generation and battery charging / discharging power are dynamically adjusted in real time. Under the premise of avoiding reverse power grid connection, the battery capacity is fully utilized to release the photovoltaic system power generation capacity and realize the efficient, continuous and stable operation of the photovoltaic power station.

[0062] Reference Figure 1 The method in this embodiment specifically includes the following processes:

[0063] (1)Real-time monitoring of user load power, battery real-time power and photovoltaic total power generation data; wherein the battery real-time power is the real-time discharge power or the real-time charging power.

[0064] (2)The difference between the sum of the user load power and the battery real-time power and the photovoltaic total power generation power is taken as the real-time power difference; specifically: real-time power difference = user load power q2 + battery real-time power q3 - photovoltaic total power generation power q1.

[0065] (3)When the system is normally running, when the real-time power difference is greater than or equal to the set value M, the battery is discharged; when the real-time power difference is less than or equal to the set value N, the battery is charged; when the real-time power difference is between the set values M and N, the battery is neither charged nor discharged.

[0066] In this embodiment, when the real-time power difference is greater than M, the battery is discharged; the greater the real-time power difference, the greater the battery discharge power; the battery retains a certain amount of power as a reserve.

[0067] When the battery reserve reaches k%, and is in a discharging state, if the battery discharge power at this time is Y, the battery discharge power is reduced from Y to 0. (k% is considered as a safety capacity, and no further discharge is allowed); the maximum power during discharging does not exceed the rated power.

[0068] During discharging, the photovoltaic cancels the maximum output power constraint.

[0069] In this embodiment, the battery discharge power adopts a step change, a function relationship between the discharge power and the available battery capacity, the real-time power difference is established, the battery discharge power is dynamically adjusted in real time, and the limitation on the photovoltaic power generation power is reduced.

[0070] The battery discharge power is specifically:

[0071] q5 = μ1 * q + μ2 * d

[0072] Wherein, q5 is the battery discharge power, q5 ≤ battery rated power q rated; μ1 is the discharge process battery capacity influence factor, μ1 = f(q); the influence factor is a function related to the current capacity of the battery.

[0073] μ2 is the discharge process power difference value influence factor, μ2 is a constant value; q is the current capacity of the battery, and d is the discharge battery power difference coefficient; at this time, the photovoltaic power generation capacity is not limited, and the upper limit value of the photovoltaic total power generation power is infinite.

[0074] d is the value of the step change, and the value of d is specifically:

[0075] When ,

[0076] When ,

[0077] When ,

[0078] When ,

[0079] When , d = (N-a);

[0080] Wherein, a is the safety margin, q1 is the total photovoltaic power generation, q2 is the user load power, q3 is the real-time power monitoring value of the battery.

[0081] The calculated battery power is set and issued to the battery device.

[0082] When the real-time power difference is less than N, the battery is charged; the smaller the real-time power difference, the greater the battery power; and the maximum charging capacity of the battery is the rated charging capacity.

[0083] In the above charging process, if the battery capacity reaches e% of the rated value, the battery charging power is X at this time. The photovoltaic power gradually decreases by X, and the reduced power is used as the upper limit of the photovoltaic power to avoid the phenomenon of photovoltaic power generation and grid connection. When the photovoltaic power reaches the set value, the battery charging power is reduced to 0, and the state of not charging and not discharging is maintained until a new discharge instruction is received. After the battery maintains the state of not charging and not discharging, the upper limit value of the photovoltaic power fluctuates with the power load, and the upper limit value = (power load-safety margin a).

[0084] When the real-time power difference is less than a, the battery is charged at the maximum power. The maximum power in the charging process does not exceed the rated power.

[0085] When M> real-time power difference > N, the battery is not charged and not discharged.

[0086] In this embodiment, the battery charging power adopts a step change, a function relationship between the charging power and the available capacity of the battery, the real-time power difference is established, the battery charging power is dynamically adjusted in real time, and the limitation on the photovoltaic power generation is reduced.

[0087] The battery charging power is specifically:

[0088] q6 = μ3 * (Q-q) + μ4 * c

[0089] Wherein, q6 is the battery charging power, q6 ≤ battery rated power q 额定; μ3 is the battery capacity influence factor during charging process, μ3 = k(q), the influence factor is a function related to the current capacity of the battery. μ4 is the power difference influence factor during charging process, μ4 is a constant value; Q is the rated capacity of the battery, q is the current capacity of the battery, and c is the power difference coefficient of the battery during charging;

[0090] c is a stepped value, and the value of c is specifically:

[0091] When ,

[0092] When ,

[0093] When ,

[0094] When ,

[0095] When ,

[0096] Wherein, a is a safety margin, q1 is the total photovoltaic power generation, q2 is the user load power, and q3 is the real-time power monitoring value of the battery.

[0097] At this time, the upper limit of the total photovoltaic power generation q4 = user load power q2 + real-time battery power q3 - safety margin a.

[0098] In combination Figure 2 , when the uncontrollable working condition leads to reverse power start, after all photovoltaic is cut off, the battery should be closed to the charging / discharging process, according to the real-time power load, the control platform sends the starting instruction with addressing function to the photovoltaic, and selects to start the photovoltaic power station. During the starting process, reverse power should not occur, and the specific starting process is as follows:

[0099] When the photovoltaic reverse power protection is triggered, the battery discharging or charging state is stopped; the current power load C1 and the number of normal operation photovoltaic H1 are obtained;

[0100] Determine whether the current power load C1 satisfies C1≥a, if yes, restart the photovoltaic system, set the upper limit of single photovoltaic power as: (C1-a) / H1; by setting the maximum power number, the real-time power of single photovoltaic can be limited.

[0101] After t time, when the photovoltaic system reaches the expected power, the photovoltaic system and the battery enter the normal operation state.

[0102] In combination Figure 3When the power load of the closed device is R, if R >= a, the management and control platform executes the "high-power device shutdown" instruction. The management and control platform stops the battery charging / discharging process, counts the power load C2, counts the number of photovoltaic operation H2, and the upper limit of the power of a single photovoltaic power generation is (C2-a) / H2. After t time, the photovoltaic and battery devices enter the normal operation state.

[0103] After the above load change is input to the management and control platform, the photovoltaic power station executes the action for a period of time, and the management and control platform executes the instruction to shut down the device.

[0104] The controller of the photovoltaic is an inverter, and a photovoltaic system is usually composed of multiple inverters, and one inverter can usually manage multiple photovoltaic panels. When the management and control platform adjusts the power of the photovoltaic power station by G, the number of currently operating photovoltaic panels H3 is counted, and the change of each photovoltaic panel is G / H3. That is, when the power of the photovoltaic system decreases, each inverter changes, rather than a certain inverter changes.

[0105] In addition, the power of a single device cannot change sharply, and the power should change at a certain change rate. That is, the power change rate of a single photovoltaic power generation cannot be greater than f kw / s (f is a safety operation setting value), and the power change rate of a single battery cannot be greater than g kw / s (g is a safety operation setting value).

[0106] The embodiment adopts a stepwise power change to reduce frequent power adjustment. A function of power and battery capacity, real-time power difference is established to realize fast charging / discharging of the battery and improve the charging / discharging frequency of the battery.

[0107] Embodiment two

[0108] In one or more embodiments, a photovoltaic-battery system operation control system is disclosed, which comprises:

[0109] A data acquisition module is configured to monitor user load power, real-time battery power, and total photovoltaic power generation data in real time; and a real-time power difference is obtained by subtracting the sum of the user load power and the real-time battery power from the total photovoltaic power generation.

[0110] A battery charging / discharging control module is configured to control the battery to discharge when the real-time power difference is greater than or equal to a set value M, control the battery to charge when the real-time power difference is less than or equal to a set value N, and control the battery to neither charge nor discharge when the real-time power difference is between the set values M and N.

[0111] It should be noted that the specific implementation of each module has been described in Embodiment One, which will not be described in detail here.

[0112] Embodiment three

[0113] In one or more embodiments, a terminal device is disclosed, comprising a server, the server comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, the processor implementing the photovoltaic-battery system operation control method in Embodiment One when executing the program. For brevity, no further elaboration is made herein.

[0114] It should be understood that, in the embodiments, the processor can be a central processing unit (CPU), and the processor can also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), ready programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0115] The memory can include read-only memory and random access memory, and provide instructions and data to the processor, and a portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0116] In the implementation process, each step of the above method can be completed by integrated logic circuits of hardware in the processor or instructions in the form of software.

[0117] Embodiment Four

[0118] In one or more embodiments, a computer readable storage medium is disclosed, wherein a plurality of instructions are stored, the instructions being adapted to be loaded and executed by a processor of a terminal device to implement the photovoltaic-battery system operation control method described in Embodiment One.

[0119] The above describes the specific embodiments of the application in conjunction with the accompanying drawings, but is not a limitation on the scope of protection of the application. Those skilled in the art should understand that various modifications or variations made by those skilled in the art on the basis of the technical solutions of the application without inventive labor are still within the scope of protection of the application.

Claims

1. A photovoltaic-battery system operation control method, characterized in that, Comprising: Real-time monitoring of user load power, battery real-time power and total photovoltaic power generation data; The difference between the sum of the user load power and the battery real-time power and the total photovoltaic power generation is the real-time power difference; When the system is running normally, when the real-time power difference is greater than or equal to the set value M, control the battery to discharge; when the real-time power difference is less than or equal to the set value N, control the battery to charge; when the real-time power difference is between the set values M and N, the battery is not charged or discharged; the battery charging power adopts a step change, specifically: wherein, is the battery charging power, is the battery capacity influence factor for the charging process, is the power difference influence factor for the charging process, is the battery nominal capacity, is the battery current capacity, is the battery power difference coefficient at charging. is a value that changes in steps, the value of the step change is specifically: Wherein, a is a safety margin, is the total photovoltaic power generation, is the user load power, is the real-time battery power monitoring value.

2. The photovoltaic-battery system operation control method of claim 1, wherein, The battery discharge power adopts a step change, specifically: wherein, is a battery capacity influence factor for the discharge process, is a power difference influence factor for the discharge process, is a current battery capacity, is a battery power difference coefficient at discharge. is a value that changes in steps, the value of the step change is specifically: Wherein, a is a safety margin, is the total photovoltaic power generation, is the user load power, is the real-time power monitoring value of the battery.

3. The photovoltaic-battery system operation control method of claim 1, wherein, When the real-time power difference is less than the safety margin a, the battery charges at the maximum power.

4. The photovoltaic-battery system operation control method of claim 1, wherein, Also comprising: After triggering the photovoltaic reverse power protection, stop the battery discharge or charge state; obtain the current power load C1 and the normal operation photovoltaic number H1; Determine whether the current power load C1 satisfies C1≥a, if yes, restart the photovoltaic system, and set the single photovoltaic power upper limit as: (C1-a) / H1; After the photovoltaic system reaches the expected power, the photovoltaic system and the battery enter the normal operation state.

5. The photovoltaic-battery system operation control method of claim 1, wherein, Also comprising: When there is a high-power equipment shutdown, assuming that the power load of the stopped equipment is R, if R≥a, stop the battery discharge or charge state; obtain the current power load C2 and the normal operation photovoltaic number H2; Set the single photovoltaic power upper limit as: (C2-a) / H2, and after the photovoltaic system reaches the expected power, the photovoltaic system and the battery enter the normal operation state.

6. The photovoltaic-battery system operation control method of claim 1, wherein, The total photovoltaic power generation power is used to charge the battery, and the reduced photovoltaic power generation power is used as the photovoltaic power generation power upper limit, which fluctuates with the power load.

7. A photovoltaic-battery system operation control system, characterized in that, Comprising: A data acquisition module for real-time monitoring of user load power, battery real-time power and total photovoltaic power generation data; the difference between the sum of the user load power and the battery real-time power and the total photovoltaic power generation is the real-time power difference; A battery charging and discharging control module for controlling the battery to discharge when the real-time power difference is greater than or equal to the set value M when the system is running normally; control the battery to charge when the real-time power difference is less than or equal to the set value N; when the real-time power difference is between the set values M and N, the battery is not charged or discharged; the battery charging power adopts a step change, specifically: wherein, is the battery charging power, is the battery capacity influence factor for the charging process, is the power difference influence factor for the charging process, is the battery nominal capacity, is the battery current capacity, is the battery power difference coefficient at charging. is a stepped value, the value of the step is specifically: Wherein, a is a safety margin, is the total photovoltaic power generation, is the user load power, is the real-time battery power monitoring value.

8. A terminal device comprising a processor and a memory, the processor being configured to implement instructions; the memory being configured to store a plurality of instructions, wherein the terminal device is configured to perform the method according to any one of claims 1-7. The instructions are adapted to be loaded and executed by the processor to perform the photovoltaic-battery system operation control method of any one of claims 1-6.

9. A computer-readable storage medium having stored therein a plurality of instructions, wherein the instructions, when executed by a processor, cause the processor to perform operations comprising: The instructions are adapted to be loaded and executed by the processor of the terminal device to perform the photovoltaic-battery system operation control method of any one of claims 1-6.

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