A distributed photovoltaic and energy storage control system and method

Abstract

The application discloses a kind of distributed photovoltaic and energy storage control system and method, control system includes multiple photovoltaic energy storage modules, multiple fusion terminals and a cloud host station, each described photovoltaic energy storage module is connected with a fusion terminal communication, the communication connection between the fusion terminal and each fusion terminal is connected with cloud host station communication;Each described photovoltaic energy storage module includes multiple distributed photovoltaic and multiple energy storage devices, the output end of each described distributed photovoltaic is connected with inverter, the output end of each described inverter is connected to energy storage device, each described distributed photovoltaic and energy storage device are connected with corresponding fusion terminal communication;The application is accessed by being connected with cloud host station to distributed photovoltaic and energy storage device, with unified flexible access capability, centralized control scheduling capability and end-to-end delay control capability, guarantee the normal operation of power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of distributed photovoltaic and energy storage control system and method, belong to electric power control technical field. BACKGROUND

[0002] Energy production accelerates clean, energy consumption is highly electrified, energy allocation is increasingly platformized, and energy utilization is increasingly efficient. The profound adjustment of energy pattern will bring profound changes to the power system.

[0003] A large number of distributed new power sources, energy storage and adjustable loads and other flexible resources have the characteristics of small capacity, many types, different parameters, and many points, which cause insufficient controllability and regulation capacity of the power grid, and bring great challenges to the stable operation and efficient management of the power grid. SUMMARY

[0004] The present application aims to overcome the deficiencies in the prior art, and provides a kind of distributed photovoltaic and energy storage control system and method, solve the controllability and regulation capacity of the existing distributed new power sources, energy storage technical problems.

[0005] To achieve the above object, the technical scheme adopted by the present application is as follows:

[0006] In a first aspect, the present application provides a kind of distributed photovoltaic and energy storage control system, including multiple photovoltaic energy storage modules, multiple fusion terminals and a cloud host station, each photovoltaic energy storage module is communicated with a fusion terminal connection, the fusion terminal is communicated with and each fusion terminal is communicated with cloud host station connection;Each photovoltaic energy storage module includes multiple distributed photovoltaic and multiple energy storage devices, the output end of each distributed photovoltaic is connected with inverter, the output end of each inverter is connected to energy storage device, each distributed photovoltaic and energy storage device are communicated with corresponding fusion terminal.

[0007] Optionally, the distributed photovoltaic, energy storage device and fusion terminal are communicated by HPLC or LORA connection, the fusion terminal and cloud host station are communicated by 4G, 5G, optical fiber or MQTT connection.

[0008] Optionally, the fusion terminal includes photovoltaic controller and energy storage controller, the fusion terminal includes photovoltaic controller and energy storage controller, the photovoltaic controller and energy storage controller are configured by JSON configuration file, and the photovoltaic controller and energy storage controller are respectively communicated with distributed photovoltaic and energy storage device by MODBUS protocol, DLT645 protocol, DLT698 protocol and IEC104 protocol.

[0009] Optionally, the photovoltaic energy storage module can control multiple distributed photovoltaic and multiple energy storage devices uniformly, and can also control a single distributed photovoltaic and a single energy storage device; the fusion terminal can control multiple fusion terminals with access to distributed photovoltaic and energy storage devices, and realize unified control and management of all distributed photovoltaic and energy storage.

[0010] Optionally, the fusion terminals are connected through fiber optical communication.

[0011] In a second aspect, the present application provides a smooth control method for distributed photovoltaic and energy storage, comprising:

[0012] Obtaining the installed capacity P of the distributed photovoltaic t , and calculating the allowed power time change rate k of the distributed photovoltaic in the sampling period T:

[0013]

[0014] In the formula, δ c is the preset fluctuation rate threshold in the time period T;

[0015] Obtaining the original power p pv (t-Δt) of the distributed photovoltaic at time t-Δt bess (t-Δt), calculating the smoothed power P hybrid (t-Δt) of the distributed photovoltaic at time t-Δt:

[0016] P hybrid (t-Δt)=p pv (t-Δt)+P bess (t-Δt)

[0017] In the formula, Δt is the sampling interval, and t is the sampling time;

[0018] Obtaining the original power p pv (t) of the distributed photovoltaic at time t hybrid , and calculating the pre-smoothing power time change rate r p (t) combining the smoothed power P p (t-Δt):

[0019]

[0020] According to the allowed power time change rate k of the distributed photovoltaic and the pre-smoothing power time change rate r p (t) of the distributed photovoltaic at time t bess , obtaining the charge and discharge power P bess (t) of the energy storage device at time t.

[0021] Optionally, the charge and discharge power P bess(t) comprises:

[0022] When r p (t) > k, the energy storage device takes k as the expected value of r1(t), and its charging and discharging power is:

[0023] P pess (t) = Δt(k - r p (t))

[0024] When r p (t) < -k, the energy storage device takes -k as the expected value of r1(t), and its charging and discharging power is:

[0025] P pess (t) = Δt(-k - r p (t))

[0026] When -k ≤ r p (t) ≤ k, the energy storage device does not output, and its charging and discharging power is:

[0027] P pess (t) = 0

[0028] Wherein,

[0029]

[0030] P hybrid (t) = p pv (t) + P bess (t).

[0031] In a third aspect, the application provides a distributed photovoltaic and energy storage control method, comprising:

[0032] Obtaining bus voltage output by each distributed photovoltaic;

[0033] When the bus voltage exceeds the maximum voltage that can be borne by the load, adjusting the reactive output of each inverter;

[0034] If the bus voltage is equal to the rated voltage of the load after adjusting the reactive output of each inverter, the adjustment is terminated;

[0035] If the bus voltage is not equal to the rated voltage of the load after adjusting the reactive output of each inverter, adjusting the reactive output of each energy storage device until the bus voltage is equal to the rated voltage of the load.

[0036] Compared with the prior art, the application has the beneficial effects:

[0037] This invention provides a distributed photovoltaic and energy storage control system and method. The control system connects the distributed photovoltaic and energy storage devices to a cloud master station, possessing unified and flexible access capabilities, centralized control and scheduling capabilities, and end-to-end time delay control capabilities. The control method solves the problem of bus voltage exceeding limits by adjusting the reactive power functions of the inverters of the distributed photovoltaic and the energy storage devices respectively, thereby ensuring the normal operation of the power grid. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a distributed photovoltaic and energy storage control system provided in Embodiment 1 of the present invention;

[0039] Figure 2 This is a flowchart of a distributed photovoltaic and energy storage control method provided in Embodiment 2 of the present invention;

[0040] Figure 3 This is a schematic diagram illustrating the working principle of the photovoltaic energy storage module provided in Embodiment 3 of the present invention. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0042] Example 1:

[0043] like Figure 1 As shown, the present invention provides a distributed photovoltaic and energy storage control system, including multiple photovoltaic energy storage modules, multiple fusion terminals, and a cloud master station. Each photovoltaic energy storage module is communicatively connected to a fusion terminal, the fusion terminals are communicatively connected to each other, and each fusion terminal is communicatively connected to the cloud master station. Each photovoltaic energy storage module includes multiple distributed photovoltaics and multiple energy storage devices. The output terminal of each distributed photovoltaic is connected to an inverter, the output terminal of each inverter is connected to an energy storage device, and each distributed photovoltaic and energy storage device is communicatively connected to a corresponding fusion terminal.

[0044] In this embodiment, the distributed photovoltaic and energy storage devices are connected to the fusion terminal via HPLC or LoRa communication. The fusion terminal is connected to the cloud master station via 4G, 5G, fiber optic, or MQTT communication. The fusion terminals are connected to each other via fiber optic communication.

[0045] In this embodiment, the fusion terminal includes a photovoltaic controller and an energy storage controller. The photovoltaic controller and the energy storage controller are configured through a JSON configuration file, and the photovoltaic controller and the energy storage controller interact with the distributed photovoltaic and energy storage devices through the MODBUS protocol, DLT645 protocol, DLT698 protocol and IEC104 protocol, respectively.

[0046] Energy storage devices can smooth the output of photovoltaic power. Distributed photovoltaic power output, from DC to AC, generates harmonics and power fluctuations after being converted by an inverter. Energy storage devices can reduce these power fluctuations and harmonic generation. (The question then abruptly shifts to a different topic: obtaining the installed capacity P of distributed photovoltaic power.) t And calculate the allowable power time variation rate k of distributed photovoltaic within the sampling period T:

[0047]

[0048] In the formula, δ c The preset volatility threshold for the time period T;

[0049] Obtain the raw power p of the distributed photovoltaic system at time t-Δt pv (t-Δt) and the charging and discharging power P of the energy storage device bess (t-Δt), calculate the smoothed power P of the distributed photovoltaic system at time t-Δt. hybrid (t-Δt):

[0050] P hybrid (t-Δt)=p pv (t-Δt)+P bess (t-Δt)

[0051] In the formula, Δt is the sampling interval, and t is the sampling time;

[0052] Obtain the raw power p of the distributed photovoltaic system at time t pv (t), and combined with the smoothed power P hybrid (t-Δt) Calculate the power time change rate r before smoothing. p (t):

[0053]

[0054] Based on the allowable power time variation rate k of distributed photovoltaic (PV) and the unsmoothed power time variation rate r of distributed PV at time t. p (t), to obtain the charging and discharging power P of the energy storage device at time t. bess (t);

[0055] Wherein, the charging and discharging power P of the energy storage device at time t is obtained. bess (t) includes:

[0056] When r p When r1(t) > k, the energy storage device takes k as the expected value of r1(t), and its charging and discharging power is:

[0057] P pess (t)=Δt(kr p (t))

[0058] When rp When r1(t) < -k, the energy storage device takes -k as the expected value of r1(t), and its charging and discharging power is:

[0059] P pess (t)=Δt(-kr p (t))

[0060] When -k≤r p When (t)≤k, the energy storage device does not generate power, and its charging and discharging power is:

[0061] P pess (t)=0

[0062] in,

[0063]

[0064] P hybrid (t)=p pv (t)+P bess (t).

[0065] Example 2:

[0066] like Figure 2 As shown, this invention provides a distributed photovoltaic and energy storage control method, employing the distributed photovoltaic and energy storage control system described above. The control method includes:

[0067] Obtain the bus voltage output from each distributed photovoltaic system;

[0068] When the bus voltage exceeds the maximum voltage that its load can withstand, adjust the reactive power output of each inverter.

[0069] If, after adjusting the reactive power output of each inverter, the bus voltage equals the rated voltage of its load, then the adjustment is terminated.

[0070] If the bus voltage is not equal to the rated voltage of its load after adjusting the reactive power output of each inverter, then adjust the reactive power output of each energy storage device until the bus voltage equals the rated voltage of its load.

[0071] Example 3:

[0072] like Figure 3 As shown, the photovoltaic energy storage module is connected to the grid (switch S1 is closed):

[0073] 1) When the output power of distributed photovoltaic is equal to the power required by the total load (both load and interruptible load), the DC power output by distributed photovoltaic is converted into AC power after inversion and is used entirely for the total load. There is almost no energy flow in the energy storage device. At this time, S2, S4, and S5 are closed and S3 is open.

[0074] 2) Distributed photovoltaic output power can meet the total load power demand, and a part of the power can be stored in the energy storage device. In the charging process, if the energy storage device energy has reached the maximum, the remaining power is sent to the grid side, at this time S2, S3, S4, S5 are closed, and the energy storage is in the charging state.

[0075] 3) Distributed photovoltaic output power cannot meet the total load power demand, and the energy storage device releases the stored power to supply the total load with distributed photovoltaic and energy storage device. If the energy storage device has reached the minimum energy state, the energy storage device stops power output. At this time, the total load is supplied through the grid side, at this time S2, S3, S4, S5 are closed, and the energy storage is in the discharging state, if the energy storage reaches the minimum capacity, S3 is turned off.

[0076] When the system is in off-grid (S1 is disconnected):

[0077] 1) Distributed photovoltaic output power is equal to the load power demand, the distributed photovoltaic output DC power becomes AC power after inversion and is all used for load, the interruptible load is disconnected, and there is almost no energy flow in the energy storage device, at this time S2, S4 are closed, and S3, S5 are disconnected.

[0078] 2) Distributed photovoltaic output power can meet the load power demand, and a part of the power can be stored in the energy storage device. In the charging process, if the energy storage device energy has reached the maximum, the remaining power is used for the interruptible load, at this time S2, S3, S4 are closed, and the energy storage is in the charging state, when the energy storage charging is completed, S5 is closed.

[0079] 3) Distributed photovoltaic output power cannot meet the load power demand, and the energy storage device releases the stored power to supply the load with distributed photovoltaic and energy storage device. At this time S2, S3, S4 are closed, and the energy storage is in the discharging state, S5 is disconnected, and the interruptible load is no longer supplied with power.

[0080] Those skilled in the art will understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer usable program code.

[0081] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0082] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0083] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0084] The above only is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the technical principles of the present application, can also make a number of improvements and variations, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. A distributed photovoltaic and energy storage control system, characterized in that, The application relates to a photovoltaic energy storage module, a fusion terminal and a cloud host station, wherein each photovoltaic energy storage module is in communication connection with a fusion terminal, the fusion terminals are in communication connection with each other, and each fusion terminal is in communication connection with the cloud host station; each photovoltaic energy storage module comprises a plurality of distributed photovoltaics and a plurality of energy storage devices, the output end of each distributed photovoltaic is connected with an inverter, the output end of each inverter is connected to an energy storage device, and each distributed photovoltaic and energy storage device is in communication connection with a corresponding fusion terminal; the photovoltaic energy storage module can uniformly control a plurality of distributed photovoltaics and a plurality of energy storage devices, and can also control a single distributed photovoltaic and a single energy storage device; the fusion terminal can control a plurality of photovoltaic energy storage modules with access to distributed photovoltaics and energy storage devices, thereby realizing unified control and management of all distributed photovoltaics and energy storage devices. The control method of the energy storage control system comprises the following steps: acquiring the bus voltage output by each distributed photovoltaic; adjusting the reactive output of each inverter when the bus voltage exceeds the maximum voltage that can be borne by the load; terminating the adjustment when the bus voltage is equal to the rated voltage of the load after adjusting the reactive output of each inverter; adjusting the reactive output of each energy storage device until the bus voltage is equal to the rated voltage of the load when the bus voltage is not equal to the rated voltage of the load after adjusting the reactive output of each inverter.

2. The distributed photovoltaic and energy storage control system of claim 1, wherein, The distributed photovoltaics, energy storage devices and fusion terminals are in communication connection through HPLC or LORA, and the fusion terminals and the cloud host station are in communication connection through 4G, 5G, optical fiber or MQTT.

3. The distributed photovoltaic and energy storage control system of claim 1, wherein, The fusion terminal comprises a photovoltaic controller and an energy storage controller, the photovoltaic controller and the energy storage controller are configured through a JSON configuration file, and the photovoltaic controller and the energy storage controller respectively exchange information with the distributed photovoltaics and the energy storage devices through MODBUS protocol, DLT645 protocol, DLT698 protocol and IEC104 protocol.

4. The distributed photovoltaic and energy storage control system of claim 1, wherein, The fusion terminals are in communication connection through optical fiber.

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