KR20190100800A - a Photovoltaic system - Google Patents

Abstract

Disclosed is a photovoltaic power generation device outputting electric energy to a system. According to an embodiment of the present invention, the photovoltaic power generation device comprises: a battery energy storage system storing or outputting electric energy; a charging control unit controlling the battery energy storage system; a system control unit obtaining weather forecast information from a weather information providing organization, predicting a photovoltaic power generation amount during a first period in accordance with the weather forecast information, calculating an electric energy amount to be compensated by the battery energy storage system during the first period based on the predicted photovoltaic power generation amount and an electric energy amount output to a system, and scheduling operation of the charging control unit; and a weather forecast device obtaining weather observation information.

Description

PV system {a Photovoltaic system}

The present invention relates to a grid-tied photovoltaic power generation system. Specifically, the present invention relates to a grid-tied photovoltaic power generation system that performs electrical energy output compensation in real time in consideration of weather observation information.

Due to depletion of fossil energy such as petroleum and environmental pollution, interest in alternative energy is increasing. Among them, photovoltaic power generation, which is a power generating large-scale electricity using solar energy by spreading solar panels attached on a large scale, is in the spotlight. Photovoltaic power generation has the advantage of no fuel cost and no air pollution or waste because it uses unlimited and no pollution solar energy.

There are two types of solar energy generation methods, standalone and grid-connected. The grid-connected method connects photovoltaic devices to existing power grids. When electricity is generated from the photovoltaic system during the day, it is transmitted and electricity is supplied from the system at night or in rainy weather. In order to use the grid-connected photovoltaic system efficiently, the idle power is stored in the Battery Energy Storage System (BESS) at light loads, and the battery energy storage system as well as the solar power is discharged when overloaded. A photovoltaic power generation system was introduced that supplies electricity to the grid.

An energy storage system (ESS) is a device that stores power supplied from a power system or supplies stored power to a power system. Accordingly, the energy storage device is operated to output the constant power to the power system by adding the stored power of the battery to the amount of power generated by the power generation device.

A photovoltaic device according to an embodiment of the present invention aims to propose a photovoltaic device that can respond to weather conditions that change in real time to stabilize the amount of electrical energy output to the system.

The solar cell apparatus according to an embodiment of the present invention, a battery energy storage system for storing or outputting electrical energy, a charging control unit for controlling the operation of the battery energy storage system, obtains weather forecast information from a weather information provider Predicting the amount of photovoltaic power generation during the first period according to the weather forecast information, and the amount of electrical energy to be compensated in the battery energy storage system during the first period based on the predicted amount of photovoltaic power generation and the amount of electrical energy output to the grid. It includes a system control unit for scheduling the charge control unit operation by calculating the and a weather observation device for obtaining weather observation information.

Photovoltaic device according to an embodiment of the present invention is carried out 24 hours a day through the weather forecast information to establish the operation plan of the power source of the power system and through the celestial observer and real-time weather information measuring instrument Extremely short-term predictions can be made. This minimizes the error of the operation plan in the power system and can ensure the stability of the power system through real-time correction. When the solar capacity is small, the energy storage device can be connected in series to completely control the output. If the output is controlled by using an electrical signal in the energy storage device, the output can be compensated at a very high speed.

1 illustrates a concept of output stabilization of solar power and energy storage devices.
2 is a graph showing the problems of the prior art.
3 is a block diagram of a grid-tied photovoltaic device according to an embodiment of the present invention.
4 is a conceptual diagram illustrating a method of predicting a solar power correction amount according to information obtained from a celestial observer and a real-time weather information collector.
5 is a flowchart illustrating an operation process of a photovoltaic device according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

1 illustrates a concept of output stabilization of solar power and energy storage devices.

As described above, the operation of photovoltaic power generation and energy storage devices is complementary to each other. In other words, when the amount of photovoltaic power generation is large, the amount of energy output from the energy storage device decreases. On the contrary, when the amount of photovoltaic power generation is low, the amount of energy output from the energy storage device increases and the amount of energy that is totally output and input into the system is reduced. It is kept constant.

As shown in FIG. 1, when the amount of renewable energy (RE) production including solar power is increased, energy output from the energy storage device may be reduced correspondingly. On the contrary, when the output of renewable energy decreases, correspondingly, the energy output from the energy storage device increases.

Specifically, the control system of the energy storage device stabilizes the power supplied to the system by measuring the output of the renewable energy source, calculating the rate of change, and transmitting the output control command to the energy storage device in a direction of decreasing the rate of change. .

2 is a graph showing the problems of the prior art.

The solid line in FIG. 2 represents the amount of renewable power generation during the day predicted according to the existing prediction technique, and the broken line represents the output amount output from the actual renewable power generation apparatus.

As shown in FIG. 2, the amount of power generated during the day predicted by the prediction technique is only a prediction, and thus can be predicted relatively roughly. Based on the predicted amount, the controller of the energy storage device may schedule the total amount of energy output during the day.

However, as shown in FIG. 2, it can be seen that the output of renewable energy actually changes rapidly with time. For example, in the case of photovoltaic power generation, the amount of power generation is drastically reduced when sunlight is blocked by clouds. When the clouds pass, the power generation recovers again. However, as shown in the dashed line in FIG. In addition, rapid generation of power generation results in deterioration of the stabilization of the total output.

Conventionally, in order to stabilize the output to the system, the system control unit first measured the output of photovoltaic power generation, and then calculated the change rate. When the rate of change is calculated, the system controller determines the output of the energy storage device. However, in this case, after the system control unit measures the output of the renewable energy, determining the output of the energy storage device may have a limit in the stabilization of the output originally intended to compensate after the entire output is changed. There is nothing else.

In other words, it is difficult to stabilize the output for a period from when there is a change in output of the renewable energy to when the energy is output from the energy storage device by detecting the output change of the renewable energy and then controlling the output of the energy storage device. there is a problem.

In order to overcome the above-mentioned problems, a method of minimizing the time required for output stabilization may be used by setting the data acquisition cycle and the control cycle for the renewable energy generation amount as short as possible. There is no difference in that it is after the change.

In addition, there is a method of installing an additional sensor that can predict the amount of power generation, such as a solar radiation sensor in the power generation module of renewable energy, and accordingly there is a method for controlling the output of the energy storage device according to the estimated amount of power generation. However, this method has a limit of information that can be expressed by the solar radiation sensor, so it may be difficult to accurately predict the amount of power generation. In addition, there is a problem that the solar radiation sensor should be installed in a relatively large area because the factors affecting the generation amount such as clouds cannot be approached in a direction. Also, as the amount of the solar radiation sensor increases, the installation cost of the communication module also increases. There is a growing problem.

3 is a block diagram of a grid-tied photovoltaic device according to an embodiment of the present invention.

Grid-connected photovoltaic device 100 according to an embodiment of the present invention is a solar cell array 101, inverter 103, AC filter 105, AC / AC converter 107, grid 109, The charging control unit 111, the battery energy storage system 113, and the system control unit 115 are included.

The solar cell array 101 combines a plurality of solar cell modules. A solar cell module is a device that generates a predetermined voltage and current by converting solar energy into electrical energy by connecting a plurality of solar cells in series or in parallel. Therefore, the solar cell array 101 absorbs solar energy and converts it into electrical energy.

The inverter 103 inverts DC power into AC power. DC power supplied by the solar cell array 101 or DC power discharged by the battery energy storage system 113 is supplied through the charging control unit 111 to invert to AC power.

The AC filter 105 filters the noise of power inverted into AC power.

The AC / AC converter 107 converts the magnitude of the voltage of the AC power from which noise is filtered to supply AC power to the system, and supplies power to the system 109.

The system 109 is a system in which many power plants, substations, transmission and distribution lines, and loads are integrated to generate and use electric power.

The charging control unit 111 controls the charging and discharging of the battery energy storage system 113. When the system is overloaded, the charging control unit 111 receives power from the battery energy storage system 113 and delivers power to the system. When the system is lightly loaded, the charging control unit 111 receives power from the solar cell array 101 and transfers the power to the battery energy storage system 113.

The battery energy storage system 113 receives and charges electric energy from the solar cell array 101 and discharges the charged electric energy according to the power supply and demand situation of the system 109. Specifically, when the system 109 is lightly loaded, the battery energy storage system 113 receives idle power from the solar cell array 101 to charge it. When the system 109 is overloaded, the battery energy storage system 113 discharges the charged power to supply power to the system 109. The electricity supply and demand situation of the system varies greatly from time to time. Therefore, it is inefficient for the grid-connected photovoltaic device 100 to uniformly supply the power supplied by the solar cell array 101 without considering the power supply situation of the grid 109. Therefore, the grid-tied photovoltaic device 100 adjusts the amount of power supply according to the power supply and demand situation of the system 109 using the battery energy storage system 113. Through this, the grid-tied photovoltaic device 100 may efficiently supply power to the grid 109.

The system controller 115 controls the operations of the charging controller 111, the inverter 103, the AC filter 105, and the AC / AC converter 107.

The photovoltaic device according to an embodiment of the present invention may further include a weather observation device 118 for observing the weather based on the location where the photovoltaic device is installed. Here, the weather observing device 118 may include at least one of the observatory 116 and the real-time weather meter 117.

It may further include at least one of the celestial observer 116 or the real-time weather meter 116. The system controller 115 may obtain weather information from the celestial observer 116, the real-time weather meter 117 (AWS), or a weather information provider and operate the solar cell apparatus based on the weather information.

The celestial observer 116 is a observing device including a convex lens and is a device capable of real-time photographing of the current weather conditions at 360 degrees. The celestial observer 116 may collect the celestial image information in real time according to a value set by the user, and collect the image information obtained by 2D modeling in a specific file format. The celestial observer 116 may obtain image information regarding the position of the sun or the position and distribution of clouds based on where the photovoltaic device is currently located.

The real time weather information collector 117 collects measurement information regarding the current wind direction or wind speed where the photovoltaic device is located. In more detail, the real-time weather information collector 117 may include a wind vane and an anemometer, and may further include solar radiation or a temperature sensor.

The angle of incidence of sunlight and the incident solar energy are determined based on the position of the sun and the position of the cloud based on the point where the photovoltaic device as the observation point exists. Accordingly, the system controller 115 adds the wind direction and wind speed information obtained from the real-time weather information collector 117 to the sun position and the cloud position obtained from the celestial observer 116 to predict the cloud movement path according to time, and Predict solar energy accordingly.

In addition, the solar cell apparatus according to the exemplary embodiment may further include a storage unit (not shown), where the storage unit may mean a storage medium or a database. The storage may store historical data about solar power. For example, the storage unit may database and store the amount of photovoltaic power generation under specific conditions, such as the amount of photovoltaic power generation at each time, the amount of photovoltaic power generated by solar radiation, or the amount of photovoltaic power generated according to solar incident angle.

According to an embodiment, the system controller 115 may estimate the amount of photovoltaic power corresponding to the weather forecast information by comparing the acquired weather forecast information with photovoltaic power generation data stored in the storage. In addition, the system controller may predict the amount of photovoltaic power generation according to the incident angle of sunlight based on the photovoltaic power generation data of the storage unit. In addition, the system control unit may predict the amount of photovoltaic power generation that changes according to the degree to which the sunlight is covered by the cloud based on the photovoltaic power generation data of the storage unit.

4 is a conceptual diagram illustrating a method of predicting a solar output compensation amount according to information obtained from a celestial observer and a real-time weather information collector.

As shown in FIG. 4, the system controller 115 obtains information for determining a sun position and a cloud position from the celestial observer 116 on the basis of the photovoltaic device 100.

For example, referring to FIG. 4, the system controller 115 may know the position t0 of the cloud of the first time and the position w0 of the sun. The system controller 115 predicts a cloud moving path and a moving speed according to wind direction and speed information obtained from the real-time meteorological government collector 117. The path of the sun is fixed, and the system controller 115 can know the position of the sun over time without any additional information.

Therefore, the system controller 115 may expect that the cloud is at the t1 position and the sun is at w1 at the second time (after a certain time has passed from the first time), and as a result, the photovoltaic device at this time The position of the sun and the amount of sunlight incident can be calculated from In addition, the system control unit 115 may also expect that the cloud is at position t2 and the sun is at position w2 at the third time (after a certain period of time from the second time), and similarly the amount of sunlight incident is calculated. Can be.

As a result, the system control unit 115 can predict the change in the amount of photovoltaic power generation in advance by predicting the position of the sun and the position of the cloud in advance, and accordingly control the output of the energy storage device to suppress the sudden change in the total output amount. It can be suppressed.

5 is a flowchart illustrating an operation process of a photovoltaic device according to an embodiment of the present invention.

The system control unit of the photovoltaic device obtains weather prediction information from a weather information provider (S101). In this case, the weather information provider may be, for example, the Meteorological Agency, and the weather forecast information may be information such as tomorrow's weather, temperature, wind direction, wind speed, sunrise / sunset time, and the like.

The system controller predicts the amount of photovoltaic generation on the next day based on the acquired weather prediction information (S103). Here, the period of one day is one example, and the system controller may predict the amount of photovoltaic generation in a longer period or a shorter period than one day.

The amount of photovoltaic power generation generally shows a constant pattern, which can be predicted from weather information including predicted temperature and sunrise / sunset time information. Therefore, the system control unit predicts the amount of photovoltaic generation on the next day based on the weather information, and accordingly schedules the charging control unit control command of the energy storage system to compensate for the photovoltaic generation.

In general, the photovoltaic prediction system calculates the monthly generation amount (E _M ) according to Equation 1 below.

Where E _Y is total annual power generation, I _Y is total annual solar radiation, and I _M is average monthly solar radiation. The system controller collects solar radiation or cloud information in units of 1 hour per day based on the obtained weather information and combines it with a power generation model to predict the weather for the next day. The weather information thus predicted may be used to predict the amount of photovoltaic generation on the next day and to schedule the photovoltaic device.

The system controller obtains observation information from the celestial observer and the real-time weather information collector (S105). The daily generation amount predicted in step S103 is information for rough scheduling, and does not correspond to a weather situation changing in real time. Therefore, the system controller obtains the observation information from the celestial observer and the real-time weather information collector in order to predict the weather situation having a great influence on the photovoltaic power generation that changes in real time. The information obtained here may be information about the position of the sun, the position and distribution of the cloud, the wind speed, and the wind direction based on the position of the photovoltaic device.

The system controller calculates a real-time compensation energy amount based on the observation information (S107). The system controller can estimate the position of the sun and the position of the cloud based on the observation information, and consequently the sunlight for a considerably shorter period than one day considering the angle of incidence by the position of the sun and the amount of incidence by the position of the cloud. It is possible to predict the change in power generation amount and to calculate the real-time output correction amount accordingly.

For example, 100 kw of energy should be output to the grid after 30 minutes, and according to the daily solar power generation based on weather information, it is assumed that 70 kw of energy is scheduled for 30 minutes. In this case, the remaining energy storage device only needs to output 30 kw of energy after 30 minutes. However, when it is predicted that the amount of photovoltaic power generation changes to 20 kw after 30 minutes according to the observation information, the system controller may preschedule to change the output compensation amount in the energy storage device from 30 kw to 80 kw.

The system controller controls the charging controller according to the calculated amount of compensation energy (S109). As described above, the amount of output correction for a predetermined period is predicted in advance, and thus the energy storage device may be rescheduled. The system controller controls the amount of compensation energy from the battery energy storage system according to the rescheduling schedule. In a specific embodiment, the system control unit may transmit the changed control command to the charging control unit.

Photovoltaic device according to an embodiment of the present invention is carried out 24 hours a day through the weather forecast information to establish the operation plan of the power source of the power system and through the celestial observer and real-time weather information measuring instrument Extremely short-term predictions can be made. This minimizes the error of the operation plan in the power system and can ensure the stability of the power system through real-time correction. When the solar capacity is small, the energy storage device can be connected in series to completely control the output. If the output is controlled by using an electrical signal in the energy storage device, the output can be compensated at a very high speed.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the present invention.

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

Claims (6)

In the photovoltaic device,
A battery energy storage system for storing or outputting electrical energy;
A charging control unit controlling an operation of the battery energy storage system;
Obtaining weather forecast information from a meteorological information providing agency, predicting the amount of photovoltaic power generation during the first period according to the weather forecast information, and performing the first period based on the predicted amount of photovoltaic power generation and the amount of electrical energy output to the grid. A system controller which calculates an amount of electrical energy to be compensated for in the battery energy storage system and schedules a charging controller operation; And
It includes a weather observation device for obtaining weather observation information,
The system controller calculates the amount of compensation electrical energy in the second period shorter than the first period based on the weather observation information to reschedule the charging control operation in the second period.
Solar power device. The method of claim 1,
The meteorological observation device includes at least one of a celestial sphere observer for observing celestial spheres based on the photovoltaic power generation device or a real-time meteorology measuring device for measuring weather information by an implementation of a place where the photovoltaic power generation device is installed.
Solar power device. The method of claim 2,
The celestial observator observes the position of the sun and the position of the cloud in the celestial sphere based on the photovoltaic device, to image the observation result,
The real-time weather meter measures the wind direction and wind speed information,
The system control unit predicts the solar power generation and the cloud movement by combining the sun position and cloud position information obtained from the celestial observer and the wind direction and wind speed information obtained from the real-time weather measuring device to predict the amount of solar power generation to change. And rescheduling the charging control operation of the second period by calculating the amount of compensated electric energy in the second period based on the predicted amount of photovoltaic power generation.
Solar power device. The method of claim 2,
The celestial observer collects real-time image information of the celestial sphere based on the photovoltaic device, 2D models the collected image information, collects the 2D modeled image information in a specific file format, and transmits the image information to the system controller.
Solar power device. The method of claim 2,
The real time weather information collector includes a wind vane and anemometer
Solar power device. The method of claim 1,
The storage unit for storing a database of the amount of generation of photovoltaic power generation according to at least one of the generation time, solar radiation or the solar light incident angle further comprises
Solar power device.

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