KR20220157842A - Method of smoothing photovoltaic output and device performing method - Google Patents

Abstract

In accordance with one embodiment of the present invention, a method for smoothing photovoltaic power generation output includes the following steps of: calculating smoothing target output by using an unscented Kalman filter based on the first output of a photovoltaic power generator inputted at a first time point and the second output of a second photovoltaic power generator inputted at a second time point after the first time point; determining an energy charging or discharging amount of an energy storage system (ESS) based on a first difference between the calculated smoothing target output and the second output; and based on the determined energy charging or discharging amount, controlling the energy storage system so as to perform charging or discharging. Therefore, the present invention is capable of reducing costs for smoothing photovoltaic power generation output.

Description

Photovoltaic power output smoothing method and device {METHOD OF SMOOTHING PHOTOVOLTAIC OUTPUT AND DEVICE PERFORMING METHOD}

The present invention relates to a solar power generation output smoothing method and a solar power generation output smoothing device performing the method.

In general, photovoltaic power generation used in a microgrid system includes a configuration of receiving sunlight to generate power and supplying the generated power to grid loads in the microgrid system.

Since the output of the photovoltaic device does not always have a constant value over time, the larger the ramp rate of the output of the photovoltaic device, the higher the voltage and frequency fluctuations of the microgrid, causing damage and damage to power system equipment. It may cause malfunction of the protection relay.

Accordingly, in the prior art, a simple moving average method and an exponential smoothing method are methods of smoothing the output using an energy storage system (ESS) in order to mitigate the ramp rate change of the solar power generation output and reduce the power system problem. this exists Among the conventional smoothing methods of photovoltaic power generation output, the simple moving average method uses relatively large data, and thus has a disadvantage in that a memory effect phenomenon may occur. In addition, the exponential smoothing method among conventional photovoltaic output smoothing methods may generate an output higher than a target output value, resulting in an increase in the capacity of the energy storage system, which is problematic.

The problem to be solved by the present invention is to provide a method and apparatus for smoothing solar power generation output.

However, the problem to be solved by the present invention is not limited to those mentioned above, and another problem to be solved that is not mentioned can be clearly understood by those skilled in the art from the description below. will be.

A photovoltaic power generation output smoothing method according to an embodiment of the present invention relates to a first output of a photovoltaic device received at a first time point and a photovoltaic device input at a predetermined second time point after the first time point. calculating a smoothing target output using an unscented Kalman filter based on the second output; determining an energy charging or discharging amount of an energy storage system (ESS) based on a first difference between the calculated smoothing target output and the second output; and controlling the energy storage system to perform charging or discharging based on the determined amount of energy charging or discharging.

The step of calculating the smoothing target output may include calculating a ramp rate of the photovoltaic power generation output; calculating a measurement error coefficient using a fuzzy logic control method based on the calculated ramp rate; and determining the smoothing target by inputting the calculated measurement error coefficient to the unscented Kalman filter, wherein the ramp rate is a value obtained by subtracting the first output from the second output at the second point in time and It may be a value divided by the time difference of the first point in time.

In the fuzzy logic control method, the steps of classifying the output of the input membership function into 5 sets, generating functions by classifying the output of the output membership function into 3 sets, and calculating the measurement error coefficient include: The step of inputting the ramp rate to the input membership function and determining the measurement error coefficient as a result of the output membership function.

The calculating of the measurement error coefficient may include determining a measurement error coefficient to have a larger value as the calculated ramp rate increases.

The photovoltaic power output smoothing method may further include providing the smoothed target output to the microgrid by the energy storage system and the photovoltaic device as a result of the control.

The step of determining the energy charging or discharging amount may include, when a difference between the calculated smoothing target output and the second output of the photovoltaic device is negative (-), the difference as an energy discharging amount of the energy storage system. and when the difference between the calculated smoothed target output and the photovoltaic power output is positive (+), the difference is determined as an energy charge amount of the energy storage system, and the smoothed output is provided to the microgrid In the step, when the difference is determined as the energy discharge amount, the energy discharge amount and the second output are provided to the microgrid, and when the difference is determined as the energy charge amount, the output obtained by subtracting the energy charge amount from the second output can be provided to this microgrid.

In another embodiment of the present invention, a photovoltaic power generation output smoothing method performed by a photovoltaic power generation output smoothing system including a photovoltaic power generation output smoothing device, a photovoltaic power generation device, and an energy storage system includes the solar power output smoothing method received at a first point in time. Calculating a target smoothing output using an undirected Kalman filter based on a first output of the photovoltaic device and a second output of the photovoltaic device received at a predetermined second point in time after the first point in time; determining an energy charging or discharging amount of the energy storage system based on a first difference between the calculated smoothing target output and the second output; and providing the smoothed target output to the microgrid by the energy storage system and the photovoltaic device by charging or discharging the energy storage system based on the determined amount of energy charging or discharging. .

A photovoltaic power generation output smoothing device according to an aspect of the present invention includes a first output of a photovoltaic device received at a first time point and a second output of the photovoltaic device received at a predetermined second time point after the first time point. 2 Transmitting and receiving unit for receiving output; and a processor controlling the transceiver, wherein the processor calculates a smoothing target output using an undirected Kalman filter based on the first output and the second output, and calculates a ratio between the calculated smoothing target output and the second output. An energy charging or discharging amount of the energy storage system may be determined based on the difference, and the energy storage system may be controlled to charge or discharge based on the determined energy charging or discharging amount.

A solar power generation output smoothing system according to another aspect of the present invention includes a solar power generation device outputting energy produced from sunlight; an energy storage system for charging some or all of the output energy of the photovoltaic device or discharging some or all of the stored energy; and smoothing using an undirected Kalman filter based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point. A target output is calculated, an energy charging or discharging amount of the energy storage system is determined based on a first difference between the calculated smoothing target output and the second output, and the energy storage system is determined based on the determined energy charging or discharging amount. A photovoltaic power generation output smoothing device for controlling the system to charge or discharge, wherein the energy storage system and the photovoltaic device transmit the smoothed target output to a microgrid according to the control of the photovoltaic power generation output smoothing device. can provide

According to an embodiment of the present invention, by using an unscented Kalman filter and a smoothing method based on fuzzy logic control, it is possible to limit the smoothing and ramp rate of photovoltaic power generation output, and to reduce the voltage and frequency variability of the microgrid to improve system quality and stability. can be improved, and the capacity of the energy storage system can be reduced. In addition, since the capacity of the energy storage system is reduced, the effect of reducing the cost of smoothing the output of the photovoltaic power generation can be achieved.

1 is a block diagram illustrating a photovoltaic power output smoothing device according to an embodiment of the present invention.
2 is a graph showing an input membership function and an output membership function of fuzzy logic control according to an embodiment of the present invention.
3 is a graph showing a comparison between a method for smoothing a photovoltaic power generation output according to an embodiment of the present invention and a photovoltaic power generation output according to another smoothing method.
4 is a graph showing a comparison between a photovoltaic power generation output smoothing method and a photovoltaic power generation output and a ramp rate according to another smoothing method according to an embodiment of the present invention.
5 is a graph showing required capacity of an energy storage system according to a photovoltaic output smoothing method and another smoothing method according to an embodiment of the present invention.
6 is a graph showing variability of frequency and voltage of a microgrid system according to an embodiment of the present invention.
7 is a block diagram for explaining the photovoltaic power generation output smoothing device according to an embodiment of the present invention in terms of hardware.
8 is a flowchart of a photovoltaic output smoothing method according to another embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to completely inform the person who has the scope of the invention, and the present invention is only defined by the scope of the claims.

In describing the embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted. In addition, terms to be described later are terms defined in consideration of functions in the embodiment of the present invention, which may vary according to the intention or custom of a user or operator. Therefore, the definition should be made based on the contents throughout this specification.

1 is a block diagram illustrating a photovoltaic power output smoothing device according to an embodiment of the present invention.

Referring to FIG. 1 , a photovoltaic power generation output smoothing system 10 may include a photovoltaic power generation output smoothing device 100, a photovoltaic power generation device 200, and an energy storage system (ESS) 300. have.

In this specification, for convenience of description, the photovoltaic power generation output smoothing device 100 is described as a device that is distinguished from the photovoltaic device 200 and the energy storage system 300, but is not limited thereto. That is, according to embodiments, the photovoltaic power generation device 200 and the energy storage system 300 may be included in the photovoltaic power generation output smoothing device 100 .

The photovoltaic power generation output smoothing device 100 receives energy output from the photovoltaic device 200 and uses the received output energy as an input of an unscented Kalman filter to charge the energy storage system 300 Alternatively, discharge can be controlled.

More specifically, when the output of the photovoltaic device 200 is excessive, the photovoltaic power generation output smoothing device 100 controls to store a part of the output of the photovoltaic device 200 in the energy storage system 300. When it is determined that the output of the photovoltaic device 200 is low, the energy stored in the energy storage system 300 may be controlled to be discharged.

Therefore, the photovoltaic power generation output smoothing device 100 controls the charging or discharging of the energy storage system 300 to provide smoothed energy to the microgrid, thereby improving system quality and stability. The required storage capacity of the energy storage system 300 can be reduced by using fuzzy logic control.

The photovoltaic device 200 can generate electric power by converting sunlight energy into DC electricity, and can use a solar panel to which several solar cells are attached. Since the output of the photovoltaic device 200 may not be constant over time, the photovoltaic power generation output smoothing device 100 uses the output of the photovoltaic device 200 as an input to generate smoothed energy to the microgrid. can provide.

The energy storage system 300 may store energy to charge or discharge energy. Also, according to embodiments, the energy storage system 300 may be a battery-based energy storage system (BESS), but is not limited thereto.

The solar power generation output smoothing device 100 can reduce the storage capacity of the energy storage system 300 required to provide smoothed energy to the microgrid, thereby reducing costs.

The photovoltaic power generation output smoothing device 100 includes a photovoltaic power generation output transceiver 110, a target smoothing energy calculation unit 120, a ramp rate calculation unit 130, a measurement error coefficient calculation unit 140, and an ESS charge/discharge energy calculation unit 150. ) may be included.

The photovoltaic power generation output transceiver 110 may receive the output of the photovoltaic device 200 from the photovoltaic device 200 . Here, the output of the photovoltaic device 200 is power, and corresponds to the power obtained by the photovoltaic device 200 produced from sunlight.

In addition, the photovoltaic power generation output transceiver 110 receives the output of the photovoltaic device 200 as an input and calculates the amount of charge or discharge energy of the energy storage system 300 calculated from the ESS charge/discharge energy calculator 150 may be transmitted to the energy storage system 300 or charge or discharge of the energy storage system 300 may be controlled.

The smoothing target energy calculation unit 120 receives the photovoltaic power generation output obtained from the photovoltaic power generation output transceiver 110 and the ramp rate value calculated from the ramp rate calculation unit 130 as inputs of an undirected Kalman filter to obtain smoothing target energy can be computed. In addition, the target smoothing energy calculator 120 may calculate the target smoothing energy by using the measurement error coefficient calculated by the measurement error coefficient calculator 140 using the fuzzy logic control method for an undirected Kalman filter.

As shown in Equation 1, the ramp rate calculator 130 may calculate a ramp rate RR representing the variability of the photovoltaic power output obtained from the photovoltaic power transmission/reception unit 110 over time.

)에서 수신된 태양광 발전 장치(200)의 제 2 출력(P_PV,i)의 차이를 제 1 시점과 제 2 시점의 차이로 나눈 값을 제 2 시점의 램프율(RR_i)로 연산할 수 있다. 연산된 램프율은 평활화 목표 에너지 연산부(120)의 무향 칼만 필터, 측정 오류 계수 연산부(140)의 퍼지 논리 제어의 입력으로 이용될 수 있다. 예를 들어, 램프율 연산부(130)는 t_i와 t_i-1사이의 시간 차이를 1분으로 설정하여, 매 1분 마다 RR_i 를 연산할 수 있다.As shown in Equation 1 above, the ramp rate calculator 130 calculates the first output P _PV,i-1 of the photovoltaic device 200 received at the first predetermined time point t _i-1 and the first A second predetermined point in time after the point in time (

A value obtained by dividing the difference between the second output (P _PV,i ) of the photovoltaic device 200 received at ) by the difference between the first time and the second time is calculated as the ramp rate (RR _i ) at the second time. can The calculated ramp rate may be used as an input for an unscented Kalman filter of the smoothing target energy calculator 120 and a fuzzy logic control of the measurement error coefficient calculator 140 . For example, the ramp rate calculation unit 130 may set the time difference between t _i and t _i−1 to 1 minute and calculate RR _i every minute.

The measurement error coefficient calculation unit 140 may calculate a measurement error coefficient by using the ratio of the reference ramp rate to the current ramp rate calculated by the current ramp rate calculation unit 130 as an input and using the input membership function and the output membership function. . Subsequently, the measurement error coefficient calculated by the measurement error coefficient calculator 140 may be used as a noise covariance coefficient of an unscented Kalman filter of the smoothing target energy calculator 120 to obtain a target smoothing value.

The fuzzy logic control of the measurement error coefficient calculation unit 140 determines the measurement error coefficient to be a larger value as the ramp rate increases, so that the measurement noise covariance of the unscented Kalman filter of the smoothing target energy calculation unit 120 increases, thereby lowering the Kalman gain. function can be set.

2 is a graph showing an input membership function (a) and an output membership function (b) of fuzzy logic control according to an embodiment of the present invention.

Referring further to (a) of FIG. 2 , the measurement error coefficient calculator 140 inputs a value expressed as a percentage of the ratio of the ramp rate calculated by the current ramp rate calculator 130 to the reference ramp rate, and obtains NB (negative big) , NM (negative medium), SS (small), PM (positive medium), and PB (positive big) input membership functions of five groups. That is, the measurement error coefficient calculation unit 140 inputs a value expressed as a percentage of the ramp rate as an input membership function of fuzzy logic control (x-axis), and calculates the degree (y-axis) of the input membership function according to each function. can decide

For example, if the percentage of the ratio of the input ramp rate is +60, the measurement error coefficient calculator 140 may output the degree of the input membership function as 0.5 by the SS function.

Referring further to (b) of FIG. 2 , the measurement error coefficient calculation unit 140 takes the degree of the input membership function as an input value and calculates three groups of S (small), M (medium), and L (large). With the output membership function, the output value, the measurement error coefficient, can be calculated. That is, the measurement error coefficient calculation unit 140 may calculate the measurement error coefficient (y-axis) according to each function by taking the degree of the input membership function as an input (y-axis) as an output membership function of fuzzy logic control.

Here, the measurement error coefficient value of the fuzzy logic control may have a value of 0 or more and 1 or less.

For example, if the degree of the input membership function is 0.5, the measurement error coefficient calculation unit 140 may output 0.7 as the measurement error coefficient according to the S function. Subsequently, the measurement error coefficient calculated by the measurement error coefficient calculation unit 140 may be used as a measurement error coefficient of the smoothing target energy calculation unit 120 for calculating the target smoothing energy.

The unscented Kalman filter is a method of estimating the average value for each time of the input by selecting a sigma point around the average value through an unscented transform as an evolution of the Kalman filter for the nonlinear model. Since the output of the photovoltaic device 200 may vary over time, the smoothing target energy calculation unit 120 calculates the smoothing target energy by using an undirected Kalman filter to reduce the variability of the output of the photovoltaic device 200. can do.

The smoothing target energy calculation unit 120 may calculate the smoothing target energy as an output by taking the current output of the photovoltaic device 200 and the output of the photovoltaic device 200 at a previous point in time as inputs to the undirected Kalman filter. .

는 k 단계에서 무향 칼만 필터의 출력을 나타내고, w_k는 노이즈 오차를 나타내나, w_k는 매우 낮은 값을 가지므로 실시예에 따라 무시할 수 있다. 또한,

는 평활화를 위한 기준 램프율이며 단순 이동 평균법을 이용하여 값을 얻을 수 있다. 무향 칼만 필터의 출력인 행렬

는 k 번째 단계에서 평활화된 출력(P_SM,k)과 평활화된 램프율(RR_SM,k)을 포함한다. 평활화 목표 에너지 연산부(120)는 k단계의 시간에 연산된 상기 값들을 기반으로 k+1 단계의 시간에서의 출력

를 연산할 수 있다.Equation 2 represents the state space equation for the unscented Kalman filter's unbiased measurement to obtain the smoothing target value. Here, matrix

denotes the output of the unscented Kalman filter at step k, w _k denotes a noise error, but w _k has a very low value and can be ignored depending on the embodiment. In addition,

is a reference ramp rate for smoothing and can be obtained using a simple moving average method. Matrix that is the output of an unscented Kalman filter

includes the smoothed output (P _SM,k ) and the smoothed ramp rate (RR _SM,k ) in the kth step. The smoothing target energy calculator 120 outputs an output at the time of step k+1 based on the values calculated at the time of step k.

can be computed.

Equation 3 represents the state space equation for observation measurements in an unscented Kalman filter. Here, P _PV,k denotes the output of the photovoltaic device 200 measured at step k, and RR _k denotes a ramp rate calculated from the ramp rate calculator 130 at step k. v _k represents a noise error, but since v _k has a very low value, it can be ignored depending on the embodiment.

The smoothing target energy calculator 120 calculates the input and output matrices of Equations 2 and 3 with an unscented Kalman filter algorithm at every k-th stage, and outputs the smoothing target output (P _SM ) as an output value at the k-th stage. can be computed. In this case, the smoothing target energy calculation unit 120 may apply the measurement error covariance of the unscented Kalman filter to the measurement error coefficient calculated by the measurement error coefficient calculation unit 140 to the algorithm. For example, the initial value of the measurement noise covariance may be set to 25.

The ESS charge/discharge energy calculation unit 150 compares the smoothing target output (P _SM ) calculated by the smoothing target energy calculation unit 120 with the output (P _PV ) of the photovoltaic device 200, and the energy storage system 300 ) may determine whether some or all of the output of the photovoltaic device 200 should be charged, or some or all of the energy stored in the energy storage system 300 should be discharged. In addition, the ESS charge/discharge energy calculation unit 150 may calculate an energy charging or discharging amount of the energy storage system 300 .

For example, when the difference between the calculated smoothing target output and the output of the photovoltaic device 200 is a negative (-) value, the ESS charge/discharge energy calculation unit 150 should discharge the energy storage system 300 by the difference. It can be calculated as the amount of energy to be calculated, and when the difference between the calculated smoothing target output and the output of the photovoltaic device 200 is a positive (+) value, the energy storage system 300 operates as much as the difference between the photovoltaic device 200 ) can be calculated as the amount of energy to be charged from the output of

3 to 6 are simulation data verified through DIgSILENT PowerFactory software in the IEEE 6 Bus Microgrid Test Feeder in order to confirm the effect difference between the embodiment of the present invention and other smoothing methods. As a limiting condition, the total load of the system is 410 kW, the solar power generation capacity is connected to 250 kW, which is 60% of the total load, and the ramp rate is limited to ± 25 kW/min.

Figure 3 (a) is a graph showing the PV output and the smoothing method according to the simple moving average method (SMA) compared with time, Figure 3 (b) is the solar power output and exponential smoothing (ESM) is a graph showing a comparison over time, and FIG. 3 (c) is a graph showing a comparison over time of a smoothing method (KF) using a solar power generation output and a Kalman filter, and FIG. 4 (d) is a graph of the present invention. It is a graph showing the comparison of the photovoltaic output and the smoothing method (UKF) using the unscented Kalman filter and the fuzzy logic control technique over time according to the embodiment of

Referring to FIG. 3 , it can be seen that in all smoothing methods, the variability of power compared to the actual solar power generation output for each time period is reduced and smoothed.

4 is a graph showing a comparison between a photovoltaic power generation output smoothing method according to an embodiment of the present invention and a photovoltaic power generation output and a ramp rate according to another smoothing method.

Referring to FIGS. 1 and 4(a) , smooth graphs of the smoothed output versus the photovoltaic power output in all methods from 600 minutes to 675 minutes show that smoothing has been achieved. Here, since the smoothing method (UKF) according to the embodiment of the present invention shows a value closer to the photovoltaic power output, the difference between the actual output and the smoothed output is smaller than other methods, so that the required energy storage system 300 It can be seen that the capacity decreases.

Referring to (b) of FIG. 4 , it can be seen that the ramp rate satisfies the limiting condition of ± 25 kW/min in all methods during the corresponding time.

5 is a graph showing required capacity of an energy storage system according to a photovoltaic output smoothing method and another smoothing method according to an embodiment of the present invention.

1 and 5, the solar power generation output smoothing device 100 sets the initial power of the energy storage system (BESS, 300) to 0, and when charging occurs, the power (BESS) of the energy storage system 300 Energy) has a positive value and when a discharge occurs, the power of the energy storage system 300 can have a negative value. The capacity of the energy storage system 300 required for output smoothing may be a value obtained by subtracting the maximum discharged power from the maximum power stored in the energy storage system 300 .

When referring to the graph, the capacity of the energy storage system 300 required for output smoothing requires the largest capacity by keeping the largest fluctuation range when using the simple moving average method (SMA), and the unscented Kalman filter according to the embodiment and In the case of the smoothing method using fuzzy logic control (UKF), it can be confirmed that the smallest capacity is required due to the smallest fluctuation range.

The required capacity of the energy storage system 300 is 52.20 kWh according to the simple moving average method, 31.58 kWh according to the exponential smoothing method, and 29.18 kWh according to the Kalman filter, whereas the unscented Kalman filter and fuzzy logic Since it is 18.51 kWh when the control method is used, according to the embodiment, the required capacity of the energy storage system 300 required for smoothing can be reduced.

6(a) is a frequency of a microgrid system according to an embodiment of the present invention, and FIG. 6(b) is a graph showing voltage variability according to an embodiment of the present invention.

Referring to (a) of FIGS. 1 and 6, when the smoothing is performed using an unscented Kalman filter and a fuzzy logic control method (UKF Method), the frequency variability of the microgrid system is higher than when the output smoothing is not performed (Actual PV). It can be seen that the frequency variability is reduced.

Referring to (b) of FIG. 6, when smoothing using an unscented Kalman filter and a fuzzy logic control method (UKF Method), the RMS voltage variability of the microgrid system is lower than when output smoothing is not performed (actual PV) can confirm.

Accordingly, the photovoltaic power generation output smoothing device 100 can improve system quality and stability of the microgrid.

7 is a block diagram for explaining the photovoltaic power generation output smoothing device according to an embodiment of the present invention in terms of hardware.

1 and 7, the photovoltaic power output smoothing device 100 includes a storage device 171 for storing at least one command, and a processor 172 for executing at least one command of the storage device 171. and a transceiver 173.

The storage device 171 may include at least one of a memory or a volatile storage medium and a non-volatile storage medium. For example, the storage device 171 may include at least one of a read only memory (ROM) and a random access memory (RAM).

The storage device 171 may further include at least one command to be executed by the processor 172 to be described later, and may store an initial setting value for output smoothing.

The processor 172 may include a central processing unit (CPU), a graphics processing unit (GPU), a micro controller unit (MCU), or a dedicated processor on which methods according to embodiments of the present invention are performed. can mean

As described above, the processor 172 operates the smoothing target energy calculation unit 120, the ramp rate calculation unit 130, the measurement error coefficient calculation unit 140, and the ESS charge/discharge according to at least one program command stored in the storage device 171. It can perform the function of the energy calculation unit 150, and each of them can be stored in a memory in the form of at least one module and executed by a processor.

The transmitting/receiving device 173 may receive or transmit data from an internal device or an external device connected through communication, and may perform the function of the photovoltaic output transmitting/receiving unit 110 . For example, the transceiver 173 may receive the output power of the photovoltaic device 200 obtained from the photovoltaic device 200 and transmit the amount of energy to charge or discharge the energy storage system 300. can do.

In the above, the photovoltaic power output smoothing device 100 according to an embodiment of the present invention has been described. Hereinafter, a photovoltaic power generation output smoothing method executed by a processor operation in the photovoltaic power generation output smoothing device according to another embodiment of the present invention will be described.

8 is a flowchart of a photovoltaic output smoothing method according to another embodiment of the present invention.

Referring to FIGS. 7 and 8 , first, the transceiver 173 inputs a first photovoltaic power generation output at a predetermined first time point and a second photovoltaic power generation output at a second time point from the photovoltaic device 200. It can be received (S100).

Subsequently, the processor 172 may calculate a ramp rate based on the first and second outputs of the photovoltaic device 200 received (S200).

The processor 172 may calculate a measurement error coefficient using a fuzzy logic control function by taking the calculated ramp rate as an input (S300).

In addition, the processor 172 may multiply the calculated measurement error coefficient by the noise covariance of the undirected Kalman filter and determine a target smoothing output by using the first output and the second output as input values (S400).

Subsequently, the processor 172 may determine an energy charging or discharging amount of the energy storage system 300 at a second time point based on the determined smoothing target output and the second output (S500).

The transceiver 173 transmits the energy charge or discharge amount of the energy storage system 300 to the energy storage system 300 or controls the energy storage system 300 to charge or discharge the smoothed output to the system of the microgrid system. It can be delivered to the load (S600)

Thus, the apparatus and method according to the embodiment of the present invention can smooth the output of photovoltaic power generation within a limited ramp rate, and also obtain the effect of cost reduction by reducing the required capacity of the energy storage system 300 .

Combinations of each block of the block diagram and each step of the flowchart accompanying the present invention may be performed by computer program instructions. Since these computer program instructions may be loaded into an encoding processor of a general-purpose computer, special-purpose computer, or other programmable data processing equipment, the instructions executed by the encoding processor of the computer or other programmable data processing equipment are each block or block diagram of the block diagram. Each step in the flow chart creates means for performing the functions described. These computer program instructions may also be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular way, such that the computer usable or computer readable memory It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the function described in each block of the block diagram or each step of the flow chart. The computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to generate computer or other programmable data processing equipment. It is also possible that the instructions performing the processing equipment provide steps for executing the functions described in each block of the block diagram and each step of the flowchart.

Additionally, each block or each step may represent a module, segment or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative embodiments, it is possible for the functions recited in blocks or steps to occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order depending on their function.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential qualities of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

10: Solar power output smoothing system
100: solar power output smoothing device
110: solar power output transceiver
120: smoothing target energy calculation unit
130: ramp rate calculation unit
140: measurement error coefficient calculation unit
150: ESS charge/discharge energy calculation unit
171: storage device
172: processor
173: transmitting and receiving device
200: solar power generation device
300: energy storage system

Claims (11)

In the photovoltaic power generation output smoothing method performed by the photovoltaic power generation output smoothing device,
An unscented Kalman filter is formed based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point. calculating a smoothing target output using;
determining an energy charging or discharging amount of an energy storage system (ESS) based on a first difference between the calculated smoothing target output and the second output; and
Based on the determined energy charging or discharging amount, controlling the energy storage system to charge or discharge.
A method for smoothing solar power output.
According to claim 1,
Calculating the smoothing target output comprises:
calculating a ramp rate of the photovoltaic output;
calculating a measurement error coefficient using a fuzzy logic control method based on the calculated ramp rate; and
Further comprising determining the smoothing target by inputting the calculated measurement error coefficient to the unscented Kalman filter,
The ramp rate is
A value obtained by subtracting the first output from the second output by the time difference between the second time point and the first time point
A method for smoothing solar power output. According to claim 2,
The fuzzy logic control method,
Classify the output of the input membership function into 5 sets, classify the output of the output membership function into 3 sets, and create a function, respectively;
Calculating the measurement error coefficient,
And inputting the input ramp rate into the input membership function, and determining the measurement error coefficient as a result of an output membership function.
A method for smoothing solar power output. According to claim 2,
Calculating the measurement error coefficient,
Determining a measurement error coefficient as a larger value as the calculated ramp rate increases,
A method for smoothing solar power output. According to claim 1,
The solar power generation output smoothing method,
As a result of the control, further comprising providing the smoothed target output to the microgrid by the energy storage system and the photovoltaic device.
A method for smoothing solar power output. According to claim 5,
The step of determining the amount of energy charging or discharging,
When the difference between the calculated smoothing target output and the second output of the photovoltaic device is negative (-), the difference is determined as an energy discharge amount of the energy storage system, and the calculated smoothing target output and the solar power generation device are negative. When the difference in photovoltaic output is positive (+), the difference is determined as an energy charge amount of the energy storage system;
The step of providing the smoothed output to the microgrid,
When the difference is determined as the energy discharge amount, the energy discharge amount and the second output are provided to the microgrid, and when the difference is determined as the energy charge amount, the output obtained by subtracting the energy charge amount from the second output is provided to the microgrid. provided in,
A method for smoothing solar power output. A solar power generation output smoothing method performed by a solar power generation output smoothing system including a solar power generation output smoothing device, a solar power generation device, and an energy storage system,
A smoothing target using an undirected Kalman filter based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point computing the output;
determining an energy charging or discharging amount of the energy storage system based on a first difference between the calculated smoothing target output and the second output; and
Providing the energy storage system and the photovoltaic device with the smoothed target output to a microgrid by performing charging or discharging by the energy storage system based on the determined energy charging or discharging amount.
A method for smoothing solar power output. a transceiver for receiving a first output of the photovoltaic device received at a first time point and a second output of the photovoltaic device received at a predetermined second time point after the first time point;
Including a processor for controlling the transceiver,
The processor
A smoothing target output is calculated using an undirected Kalman filter based on the first output and the second output, and an energy charging or discharging amount of the energy storage system is calculated based on a difference between the calculated smoothing target output and the second output. and controlling the energy storage system to perform charging or discharging based on the determined energy charging or discharging amount.
Solar power output smoothing device. a photovoltaic device that outputs energy produced from sunlight;
an energy storage system for charging some or all of the output energy of the photovoltaic device or discharging some or all of the stored energy; and
A smoothing target using an undirected Kalman filter based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point An output is calculated, an energy charging or discharging amount of the energy storage system is determined based on a first difference between the calculated smoothing target output and the second output, and the energy storage system is determined based on the determined energy charging or discharging amount. Including a photovoltaic power generation output smoothing device that controls to perform this charge or discharge,
The energy storage system and the photovoltaic device provide the smoothed target output to the microgrid under the control of the photovoltaic power generation output smoothing device.
Solar power output smoothing system. As a computer program stored in a computer readable recording medium,
The computer program,
Including instructions for causing a processor to perform a photovoltaic power generation output smoothing method performed by a photovoltaic power generation output smoothing device;
The method,
An unscented Kalman filter is formed based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point. calculating a smoothing target output using;
determining an energy charging or discharging amount of an energy storage system (ESS) based on a first difference between the calculated smoothing target output and the second output; and
Based on the determined energy charging or discharging amount, controlling the energy storage system to charge or discharge.
computer program. A computer-readable recording medium storing a computer program,
The computer program,
Includes instructions for causing a processor to perform a photovoltaic power generation output smoothing method performed using an energy storage system (ESS),
The method,
An unscented Kalman filter is formed based on the first output of the photovoltaic device received at a first time point and the second output of the photovoltaic device received at a predetermined second time point after the first time point. calculating a smoothing target output using;
determining an energy charging or discharging amount of an energy storage system (ESS) based on a first difference between the calculated smoothing target output and the second output; and
Based on the determined energy charging or discharging amount, controlling the energy storage system to charge or discharge.
A computer-readable recording medium.

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