JP6097601B2 - Solar cell control device - Google Patents

Description

  The present invention relates to a control device for a solar cell.

  A solar cell has a characteristic that output power with respect to an operating voltage or an operating current varies depending on changes in the amount of solar radiation and temperature. Therefore, when controlling the solar cell, it is important to set the output voltage of the solar cell at an operating point where the maximum power can be extracted (hereinafter, the maximum power point). Control for automatically tracking the maximum power operating point and improving the power generation efficiency of the solar cell is called maximum power point tracking control.

  Many methods have been proposed for maximum power point tracking control. Among them, a hill-climbing method with relatively good tracking performance and a simple sequence is widely used, and Patent Document 1 describes the sequence. In the hill-climbing method, if the change amount ΔP of the power P when the superimposed voltage ΔV is added during operation with the output voltage V0 is positive, the output voltage V0 is determined to be smaller than the maximum power point voltage Vmax, If V0 + ΔV is a new operating point and the change ΔP is negative, it is determined that the output voltage V0 is larger than the maximum power point voltage Vmax, and V0−ΔV is a new operating point, and this operation is repeated. Thus, the output of the solar cell is brought close to the maximum power point for a while.

  Patent Document 2 discloses a control method for causing a maximum power point to follow at high speed. When the operating voltage changes in either the increasing direction or the decreasing direction for the set number of times, the operating voltage is controlled so that the change width of the operating voltage becomes relatively large. When the change is repeated, high-speed tracking is realized by controlling the change width of the operating voltage to be relatively small.

JP 61-97721 A JP-A-8-44445

  In the maximum power point tracking control disclosed in Patent Document 1, it is possible to track the vicinity of the maximum power point for characteristics with small amounts of solar radiation and temperature changes. However, if the solar radiation changes suddenly, the power is greatly lost because the mountain climbs again after having deviated greatly from the maximum power point. For this reason, it is considered that hill climbing is performed at a high speed to shorten the arrival time to the maximum power point and reduce power loss. However, the speed-up effect of the hill-climbing method is effective only for a certain rate of change in solar radiation. When the amount of solar radiation changes at a speed slower than this speed, the voltage commanded by the maximum power point tracking control is the true maximum. Deviation from the power point voltage causes a new power loss.

  When the maximum power point tracking control disclosed in Patent Document 2 is used, the variation range of the operating voltage is expanded when the variation range of the solar radiation amount is increased, and thus the maximum power point can be tracked at high speed. However, the above superimposed signal needs to be applied until the actual voltage follows the change in the voltage command value. This time may be relatively long depending on the characteristics of the load device. Furthermore, when taking in voltage and current values, the average value is periodically sampled for calculation, and the sequence processing from the average value acquisition is performed at a constant cycle of 0.1 to 1 second. A single follow-up process requires a certain amount of time and cannot follow changes in operating points due to solar radiation fluctuations or load fluctuations during this time.

  In view of the above, an object of the present invention is to examine the above-described problems of the prior art and to provide a solar cell control device that can cope with a more rapid change in solar radiation.

  A typical example of means for solving the problems according to the present invention is a solar cell control device, which is a power measurement unit that measures the power value of the solar cell, and a voltage that determines the operating voltage of the solar cell. A control unit, an averaging unit that integrates the power values and calculates an average value of the power values, a threshold value calculated from deviation information of the power values and the number of integrations, and the power value measured by the power measurement unit and the average A maximum power point tracking control unit that compares the absolute value of the difference value of the values and generates a voltage command value that determines the operating voltage when the absolute value of the difference value is greater than the threshold value and stops the integration. It is characterized by that.

  If the present invention is used by the above means, it is possible to provide a more efficient control device for a photovoltaic power generation system.

It is a block diagram which shows the structure of the solar energy power generation system which concerns on the Example of this invention. It is a block diagram of the electric power averaging part which concerns on the Example of this invention. It is a block block diagram of AVR control according to an embodiment of the present invention. It is a flowchart of the maximum electric power point tracking control which concerns on Example 1 of this invention. It is a flowchart of the movement voltage width setting which concerns on Example 1 of this invention. It is a timing chart at the time of mounting the conventional hill-climbing method. It is a timing chart which shows the effect of the invention which concerns on Example 1 of this invention. It is a timing chart which shows the effect of the modification of Example 1 of this invention. It is a flowchart which shows the operation | movement which resets from the continuous operation at the time of the system disturbance which concerns on Example 2 of this invention. It is a flowchart of the movement voltage width setting which concerns on Example 2 of this invention. It is a timing chart which shows the effect of Example 2 of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a photovoltaic power generation system that employs a power conditioner 7. The power conditioner 7 converts the DC power generated by the solar cell array 1 into AC synchronized with the AC power system line 6 of the system. Reference numeral 6 denotes a general power system line, for example, a line having an AC voltage of 200 V or 400 V and a frequency of 50 or 60 Hz. This is a line to which loads of general consumers are connected. The power conditioner 7 includes a DC / AC inverter 2, a power measuring unit 31, a voltage measuring unit 32, a power averaging unit 3, an AVR control unit (Automatic Voltage Regulator) 4, and a maximum power point tracking control unit 5. . The inverter 2 converts the DC power generated by the solar cell array 1 into AC power (commercial power) synchronized with the system voltage. A PWM signal is supplied from the AVR control unit 4 (Automatic Voltage Regulator) to the inverter 2 so as to control the operating voltage of the solar cell array 1.

  The generated power from the solar cell array 1 is supplied to the inverter 2 and, as information for controlling the output of the solar cell array 1, the power is measured in the form of DC power and voltage from the power measuring unit 31 and the voltage measuring unit 32. It is taken into the conditioner 7. The power information taken into the power conditioner 7 is averaged by performing a plurality of periodic samplings in the power averaging unit 3. The power averaging unit 3 transmits two pieces of information, that is, power information in which measurement uncertainty is suppressed and power information captured from the solar cell array 1 to the maximum power point tracking control unit 5. In the maximum power point tracking control unit 5, a set voltage for the next search is determined according to the logic described later, and a voltage command value is sent to the AVR control unit 4.

FIG. 2 is a block diagram illustrating the function of the power averaging unit. Currently, the value of the captured DC power is P [n], and the DC power sampled immediately before is expressed as P [n-1], similarly P [n-2],..., P [0]. m is a sampling number, and z ^-1 is a symbol for outputting the input delayed by one sample time. The current value and the one delayed by one sample are added together, and the value is 1 / m and averaged. That is, as the number of times of sampling increases, the uncertainty Uc of measurement data increases by (√m) times. This averaging by sampling is hereinafter referred to as an averaging process.

  FIG. 3 is a block diagram showing functions of the AVR control unit 4. PI control is performed using the voltage command value transmitted from the maximum power point tracking control unit 5 and the voltage taken into the power conditioner 7 from the solar cell array 1, and the comparator 9 performs comparison with the triangular wave. Thus, it is converted into a PWM signal having a conduction ratio corresponding to the voltage command value. A transfer function indicating the PI control is expressed as K2 × {K1 + (1 / (τ · s))} (K1 and K2 are predetermined constants). Here, the time until the actual voltage converges to the voltage command value is set to about 5τ. This waiting until convergence is hereinafter referred to as AVR waiting.

  FIG. 4A shows a flowchart according to the present invention. First, in step S1, DC power P [m] and DC voltage V * are captured from the solar cell array 1, and Pave [m-1] is captured from the power averaging unit. Pave [m−1] is the average power of DC power P [0], P [1],..., P [m−1]. Next, in step S2, a measurement uncertainty Uc is calculated. The measurement uncertainty Uc up to m−1 times is obtained by calculating the standard deviation of P [0], P [1],..., P [m−1]. In general, it is known that the standard deviation is suppressed to 1 / (√n) when the sampling number n increases. Assuming that the amount of solar radiation does not change here, the mth measurement value P [m] is basically the average value of P [0], P [1], ..., P [m-1] Located at Pave [m-1] ± standard deviation Uc. That is, as shown in step S3, when the m-th measurement value P [m] is located within the average value Pave [m-1] ± standard deviation Uc, the change in the amount of solar radiation is In step S4, the sampling count is incremented (m ++) and Pave [m-1] is substituted for power power. This increment operation is performed until the set sampling number n is reached (step S5). On the other hand, if the m-th measurement value P [m] is not within the average value Pave [m-1] ± standard deviation Uc, it is considered that the amount of solar radiation has changed suddenly, The latest power P [m] after the change of solar radiation is taken in (step S6).

  In either case, when the averaging process for the sampling number n is completed or the acquisition of the latest power P [m] is completed, the acquired power is used, and the extreme value is monitored and the extreme value at S7 and S8. It is determined whether or not there is an operating point in the vicinity. Examples of the extreme value determination method include the methods described below.

  In extreme values,

が成り立つので、変形すると、以下の関係が成り立つ。

Therefore, the following relationship holds when it is deformed.

今回の最大電力点制御時の電圧指令値をV2、取り込んだ電力値powerをP2、前回の最大電力点制御時の電圧指令値をV1、取り込んだ電力値power をP1とし、電流値をそれぞれI1＝P1/V1, I2＝P2/V2と計算すると、ΔI=（I2-I1），ΔV=（V2-V1），I2，V2の関係から動作点が極値付近にあるか否かの判断は可能である。ステップS8において、極値付近にいると判断されれば、ステップS10に移動し、山登り法のような通常の最大電力点追従制御を適用する。極値付近にいないと判断されれば、ステップS9に移動し、後述する論理に従い、移動電圧幅を設定する。

The voltage command value at this maximum power point control is V2, the captured power value power is P2, the voltage command value at the previous maximum power point control is V1, the captured power value power is P1, and the current value is I1 = P1 / V1, I2 = P2 / V2, and the determination of whether the operating point is near the extreme value from the relationship of ΔI = (I2-I1), ΔV = (V2-V1), I2, V2 Is possible. If it is determined in step S8 that it is in the vicinity of the extreme value, the process moves to step S10, and normal maximum power point tracking control such as a hill-climbing method is applied. If it is determined that it is not near the extreme value, the process moves to step S9, and the moving voltage width is set according to the logic described later.

  When step S9 and step S10 are completed, the voltage command value is set in step S11. Here, if the difference between the previous voltage command value and the current voltage command value is small, the AVR standby time is set to about 2τ with respect to the time constant τ in FIG. 3, and the previous voltage command value and the current voltage are set. If the difference between the command values is large, standby time control such as setting to about 5τ is performed. Thereafter, the voltage command value is transmitted to the AVR control unit 4 (step S11), and the response time set in step S13 is waited. Lastly, when the sampling frequency variable m is initialized to 0 and the sampling frequency n is transmitted to the power averaging unit 3 (step S14), one sequence of the maximum power tracking control is completed and fed back to step S1. .

  Details of the method of calculating the moving voltage width are described below. The characteristic formula of the solar cell is represented by formula (3).

ここで、Iは太陽電池の出力電流、Vは太陽電池の出力電圧、Iscは短絡電流、pは日射量、Isは太陽電池セルの逆方向飽和電流、nfはダイオード接合定数、kはボルツマン定数、Tは絶対温度、Ncellはセル数、qは素荷量、Rsは太陽電池セル同士を接続する配線などの直列抵抗値、Rshは太陽電池セルのシャントを表す。簡単のため、Rs≒0、Rsh≒∞として電圧の式として変換すると式（４）になる。

Where I is the output current of the solar cell, V is the output voltage of the solar cell, Isc is the short circuit current, p is the amount of solar radiation, Is is the reverse saturation current of the solar cell, nf is the diode junction constant, and k is the Boltzmann constant , T is the absolute temperature, Ncell is the number of cells, q is the amount of load, Rs is the series resistance value of the wiring connecting the solar cells, Rsh is the shunt of the solar cells. For simplicity, when converted as a voltage equation with Rs≈0 and Rsh≈∞, Expression (4) is obtained.

日射量変化前ｐ１における極値付近で動作する電流値をIm1と、日射変化後ｐ２における電流値をI1とすると、変化前後における電圧値は同じであるため、式（４）を以下のように展開することができる。

If the current value operating near the extreme value at p1 before the change in solar radiation is Im1, and the current value at p2 after the change in solar radiation is I1, the voltage value before and after the change is the same, so equation (4) is expressed as follows: Can be deployed.

対数内は、1となるので、以下の関係が成り立つ。

Since the logarithm is 1, the following relationship holds.

同様に、日射量変化前ｐ１における極値付近で動作する電流値Im1、日射変化後ｐ２における電流値Im２として、変化前後における移動すべき電圧幅ΔVを求めると、

Similarly, the voltage width ΔV to be moved before and after the change is obtained as a current value Im1 operating near the extreme value at p1 before the change in solar radiation and a current value Im2 at p2 after the change in solar radiation.

となる。一般に、太陽電池特性について、日射量が異なる場合における短絡電流と最大動作電流の関係は、式（８）のような関係になると知られており、式（８）を式（７）に代入すると、式（９）の関係が成り立つ。

It becomes. In general, regarding solar cell characteristics, it is known that the relationship between the short-circuit current and the maximum operating current when the amount of solar radiation is different becomes a relationship such as Equation (8), and substituting Equation (8) into Equation (7) The relationship of equation (9) holds.

ここで、式（６）を変形し、式（８）を用いて、以下のように変換する。

Here, equation (6) is transformed and converted as follows using equation (8).

ｊはおよそ0.9の値を取ることが一般的であるが、簡単のため、ｊ＝1.0と設定すると、式（１０）を用いて、式（９）は、

Generally, j takes a value of about 0.9. For simplicity, when j = 1.0 is set, using equation (10), equation (9) becomes

で表すことが出来る。ここで、Im1とI1の動作電圧は同じなので、電流値を電力値として置き換えることも可能である。

It can be expressed as Here, since the operating voltages of Im1 and I1 are the same, the current value can be replaced with the power value.

  In the flow of FIG. 4 (a), if the power value power captured at the time of the previous maximum power point control is P1, and this time the captured power value power is P2, P2 has uncertainty Uc, so P2 ± Uc There is a true value in the range. Here, when the expression of uncertainty is considered as% notation Uc ′, it becomes P2 × (1 ± Uc ′), and therefore Expression (11) can be expressed by Expression (12) or Expression (13).

図4（ｂ）に、図４（ａ）中のステップS9の移動電圧幅設定の詳細なフローチャートを示す。まず、ステップS15にて、電力の比と大小関係の比較を行うための閾値Pthを設定する。この閾値は変動幅を決めるための条件分岐で使用する。閾値決定後、P2とP1から電圧の移動方向を決める信号Signを１または−１で設定する(ステップS16)。Sign=1の時は、電力が増加した場合であり、不確かさUcはプラス方向にシフトする。Sign=-1の場合は電力が減少した場合であり、不確かさUcはマイナス方向にシフトする。次に、ステップS17において、不確かさの表現を％に変換し、最後に、電力の比を式（１２）の対数内のような形で算出する（ステップS18）。

FIG. 4B shows a detailed flowchart for setting the moving voltage width in step S9 in FIG. First, in step S15, a threshold value Pth for comparing the power ratio and the magnitude relationship is set. This threshold value is used in a conditional branch for determining the fluctuation range. After the threshold is determined, a signal Sign for determining the voltage movement direction is set to 1 or -1 from P2 and P1 (step S16). When Sign = 1, the power is increased, and the uncertainty Uc shifts in the positive direction. When Sign = −1, the power is decreased, and the uncertainty Uc shifts in the negative direction. Next, in step S17, the expression of uncertainty is converted into%, and finally the power ratio is calculated in a form that is within the logarithm of equation (12) (step S18).

  After setting the above parameters, the power ratio is compared with the threshold value Pth. If the power ratio is larger than the threshold value, the threshold value Pth is raised to a power and a new comparison is made with the power ratio. The voltage shift width is determined by multiplying the reference width of the fluctuation width by an integer according to the number of power multipliers that satisfy the condition (steps S19 to S24).

  FIG. 5 (a) is a timing chart when the conventional hill-climbing method is implemented, and FIG. 5 (b) is a timing chart when the present invention is implemented. In FIG. 5A, both the averaging process and the AVR standby time are set at a fixed time. When the amount of solar radiation changes abruptly at t0 in the figure, in FIG. 5A, the voltage command value is updated at t1 while waiting for the averaging process to end with the voltage command value before the sudden change in solar radiation amount. The maximum power point is followed by the hill-climbing method. In this case, even if the follow-up control for five cycles is performed from t1, the theoretical value of the maximum power point after the sudden change in solar radiation is not reached. On the other hand, in FIG. 5B, the averaging process is terminated simultaneously with the sudden change in the amount of solar radiation, and the voltage command value is updated at t0. The moving voltage width ΔV is a shift amount determined from the equation (13), and even in the case where the value of the sampling uncertainty of the averaging process has not converged due to an insufficient number of samplings, the moving voltage width ΔV can reach the maximum power point without a problem. Has reached.

FIG. 5C is a timing chart when the modified example of the invention according to the present embodiment is implemented, and is an example in which the AVR standby time is varied in accordance with the moving voltage width ΔV. In FIG. 5B, for example, if the AVR standby time is set to 5τ at which convergence is 99% or more, in FIG. It is set. When the moving voltage width by the maximum power point tracking control is small, even if the AVR standby time is set to 1 × τ and 2 × τ with respect to τ in FIG. On the other hand, when the amount of solar radiation increases at t2 in the figure, P [m] exceeds the value of Pave [m-1] + standard deviation Uc at t3, so power = P [m] And the moving voltage width ΔV ₁ is determined from the equation (13). Here, since the moving voltage width ΔV ₁ is large, the AVR standby time is set to 5τ at which convergence is completed by 99% or more, and is brought close to the maximum power point. Similarly, when the amount of solar radiation decreases at t4 in the figure, P [m] falls below the value of Pave [m-1] -standard deviation Uc at t5, so power = P [m]. From the equation (13), the moving voltage width ΔV ₂ is determined. Here, since the moving voltage width ΔV ₂ has a certain size, the AVR standby time is set to about 3τ.

  Thus, the solar cell control device 7 according to the present embodiment integrates the power value with the power measurement unit 31 that measures the power value of the solar cell, the voltage control unit 4 that determines the operating voltage of the solar cell, and the like. An averaging unit 3 that calculates an average value of the power value, a threshold value that is calculated from deviation information of the power value and the number of times of integration, an absolute value of a difference value between the power value measured by the power measurement unit and the average value, And a maximum power point tracking control unit 5 that generates a voltage command value for determining an operating voltage when the absolute value of the difference value is larger than a threshold value. With such a configuration, the solar cell control device according to the present embodiment can sufficiently respond the solar cell to the variation in solar radiation of the sequence processing time of the maximum power point tracking control once, and the use efficiency of the solar cell can be improved. Can be improved.

  FIG. 6A is a timing chart in the case where the present invention is implemented in an operation for returning from continuous operation at the time of system disturbance. Concerning photovoltaic power generation facilities, if a simultaneous disconnection occurs due to a wide range of instantaneous voltage drop due to a grid transmission line accident, etc., the entire system may be greatly affected. Through) is required, and when returning from continuous operation when this system is disturbed, a high-speed return operation is required up to an output of 80% or more before the voltage drops. To cope with this high-speed operation, when the return operation starts in step S25, first, in step S26, the DC power P [0], the average value Po of DC power immediately before the continuous operation, and the voltage command immediately before the continuous operation The value V is taken in, and then the process proceeds to step S27, where the moving voltage width is set according to the logic described later.

  Thereafter, as in the first embodiment, the determined voltage command value and the AVR standby time are transmitted to the AVR control unit 4, the variable m of the number of samplings is initialized to 0, and the sequence proceeds to the maximum power tracking control sequence. To do.

  FIG. 6B is a flowchart for explaining in detail the setting of the moving voltage width. Since the DC power P [0] is a value obtained by averaging processing once, the DC power P [0] includes a measurement uncertainty Uc derived from a measuring instrument error or the like. This uncertainty Uc is set in step S34. Next, the set voltage 1 necessary for recovery to 80% of the output is determined in steps S35 and S36 using equation (14).

次に、継続運転直前の直流電力の平均値Poと直流電力P[0]-Ucの電力の比をステップS37で求め、式（１５）を用いて、ステップS38にて、設定電圧２を決定する。

Next, the ratio of the average value Po of DC power immediately before continuous operation and the power of DC power P [0] -Uc is obtained in step S37, and the set voltage 2 is determined in step S38 using equation (15). To do.

P[0]から不確かさUcを引くのは、ワーストケースを仮定した計算を行い、なるべく移動電圧幅を大きめに設定するためである。ここで、電圧指令値について、系統擾乱時の継続運転前の値を保持させておくと、図３に示したAVR制御部の入力は、電圧指令値Vと設定電圧２である。この状態において、出力の80％まで回復させるには、AVR制御部の入力が、電圧指令値が設定電圧１で取り込み電圧が設定電圧２であれば良いので、ステップS39において、電圧比を（V‐設定電圧２）/（設定電圧１‐設定電圧２）として、この電圧比に合わせたAVR待機時間を設定する。例えば、電圧比が0.63未満であれば、待機時間を図３中のτに対して、1×τの設定にすれば十分であり、同様に、電圧比が0.86未満であれば2×τ、電圧比が0.95未満であれば3×τと設定すれば待機時間としては十分である。（ステップS40〜S42）
図７は、本発明を実装した場合のタイミングチャートであり、系統擾乱時の継続運転から復帰したタイミングにて、AVR待機時間を可変させた場合のタイミングチャートである。ここでは、通常のAVR待機時間を5×τと設定している。図中t6において、系統擾乱時の継続運転から復帰した場合、サンプリング回数をインクリメントせず1回で終了し、抑制されていない標準偏差Ucの値を鑑みながら、現在の電圧（残留電圧）を式（１４）（１５）から推定し、出力８０％回復するためのAVR待機時間を3τ程度に設定する。

The reason why the uncertainty Uc is subtracted from P [0] is to perform the calculation assuming the worst case and to set the moving voltage width as large as possible. Here, regarding the voltage command value, if the value before the continuous operation at the time of the system disturbance is held, the inputs of the AVR control unit shown in FIG. 3 are the voltage command value V and the set voltage 2. In this state, in order to recover up to 80% of the output, the input of the AVR control unit only needs to have the voltage command value set voltage 1 and the input voltage set voltage 2, so in step S39, the voltage ratio is set to (V -Set AVR standby time according to this voltage ratio as (set voltage 2) / (set voltage 1-set voltage 2). For example, if the voltage ratio is less than 0.63, it is sufficient to set the standby time to 1 × τ with respect to τ in FIG. 3. Similarly, if the voltage ratio is less than 0.86, 2 × τ, If the voltage ratio is less than 0.95, setting 3 × τ is sufficient for the standby time. (Steps S40 to S42)
FIG. 7 is a timing chart when the present invention is implemented, and is a timing chart when the AVR standby time is varied at the timing of returning from the continuous operation at the time of system disturbance. Here, the normal AVR standby time is set to 5 × τ. At t6 in the figure, when returning from continuous operation at the time of system disturbance, sampling is not incremented and the process ends in one time, and the current voltage (residual voltage) is calculated while taking into account the unsuppressed standard deviation Uc value. (14) Estimate from (15), and set the AVR standby time for recovery of 80% output to about 3τ.

  As described above, the maximum power point tracking control unit changes the standby time until the operating voltage converges according to the difference between the voltage value measured by the voltage measurement unit and the voltage command value, so that when the system disturbance occurs As for the return response from the continuous operation, it is possible to return at high speed and to shift to the maximum power follow-up operation without needless time, so that the utilization efficiency of the solar cell is improved.

DESCRIPTION OF SYMBOLS 1 ... Solar cell array 2 ... DC / AC inverter 3 ... Current averaging part 4 ... AVR control part 5 ... Maximum point tracking control part 6 ... System 7 ... Power conditioner 8 ... PWM waveform generation circuit 31 ... Electric power measurement part 32 ... Voltage measurement unit.

Claims (3)

A power measurement unit for measuring the power value of the solar cell;
A voltage control unit for determining an operating voltage of the solar cell;
An averaging unit that integrates the power values and calculates an average value of the power values;
Based on the standard deviation of the power value and the average value calculated by the averaging unit, it is determined whether the power value measured by the power measurement unit is within the standard deviation of the average value, If not within the standard deviation, the averaging unit is instructed to stop the integration of the power value, a power command value for determining the operating voltage is generated, and the power command value is sent to the voltage control unit. a maximum power point tracking unit for transmitting, to possess,
The voltage control unit determines an operating voltage of the solar cell based on the voltage based on the power value measured by the power measurement unit and the transmitted power command value. apparatus. In claim 1,
Said voltage command value is determined from the deviation information when the ratio of the second power obtained at the characteristic variations of the first power and the solar cell obtained by the power measurement unit, a second power obtained A control device for a solar cell. In claim 1,
The maximum power point tracking control unit sets a standby time of the voltage control unit until the operating voltage converges according to a difference between the voltage value measured by the voltage measurement unit and the voltage command value. A solar cell control device.

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