KR101614224B1 - Pv simulator applying hysteresis control and con - Google Patents

Abstract

Disclosed is a photovoltaic (PV) simulation device simulating an output of a PV array composed of a PV cell according to a preset I-V characteristic curve of the PV cell and outputting the simulated result. The PV simulation device comprises: a DC power source; a voltage converting unit converting a voltage of the DC power source and providing the converted voltage to a load; a control mode determining unit determining a control mode according to magnitudes of an output voltage and an output current of the voltage converting unit and an increase or decrease in an output voltage from the voltage converting unit; a PV modeling unit generating a reference voltage or a reference current using a preset PV modeling method according to the control mode determined by the control mode determining unit; and a main controller controlling the output voltage or the output current from the voltage converting unit by comparing the output voltage or the output current from the voltage converting unit with a reference voltage or a reference current provided from the PV modeling unit. According to the PV simulation device, a stable output and excellent dynamic characteristics can be secured in every operational section of the PV array.

Description

PV SIMULATOR APPLICATION HYSTERESIS CONTROL AND CON "

The present invention relates to a PV simulation apparatus and a control method thereof, and more particularly, to a PV simulation apparatus and a control method thereof, and more particularly, to a hysteresis control system To an applied PV simulation apparatus and a control method thereof.

Generally, solar power plants consist of PV (PhotoVoltaic) array and Power Conditioning System (PCS). The PV array functions as a solar cell array, a solar panel, a solar module, and the like (hereinafter referred to as a PV array). In addition, the power conditioning system converts the DC power output from the PV array into an AC form and supplies it to the system.

In order to install a PV array for solar power generation, a total open space of about 2 m ² per 1 kW of production power is normally required. Also, since the output of the PV array is affected by the climatic environment of the installation location, the performance of the power conditioning system can not be tested freely for the desired weather conditions.

To overcome these limitations, a PV simulation device was introduced.

The PV simulation device is a device for simulating the output of a PV array, which can occupy a small space of less than 0.1 m ² per 1 kW of production power and can freely test the operating performance of a power conditioning system according to climate conditions. In addition, long-length DC cables are not required for connection to the PV array, allowing for performance testing of power conditioning circuits with long term climatic conditions with high reliability without voltage drop or power loss in the cable. In addition, by adopting a switching power conversion circuit, a performance test can be performed with high efficiency. Due to the advantages of such a PV simulation device, IEC EN50530, which is a standard of PV efficiency standard, requires that a PV simulation device be used to evaluate the performance of a PV power conditioning system.

Such a PV simulation apparatus should implement the power characteristics of a PV array having a combination of a voltage source and a current source so that the output characteristics of the PV array can be the same as the output characteristics of the PV array. That is, the PV simulation device should operate in the form of a current source near the short circuit operating point (I _SC ) of the PV array and in the form of a voltage source near the open circuit operating point (V _OC ) of the PV array. Also, the PV simulation device should have intermediate operating characteristics near the maximum power operating point (MPP) of the PV array, not current source or voltage source.

Accordingly, there is a difficulty in controlling the output of the PV simulation apparatus in the intermediate operation region near the maximum power operating point (MPP), which must simultaneously implement the two power source characteristics of the current source and the voltage source.

Therefore, the present invention can stably provide the output in the entire operation region between the short circuit operation point and the open circuit operation point, and more particularly, to the PV simulation apparatus which can control the output stably in the intermediate operation region And a control method thereof.

According to an aspect of the present invention,

A PV simulation apparatus for outputting and outputting an output of a PV array made up of the PV cell according to a predetermined I-V characteristic curve of the PV cell,

DC power supply;

A voltage converting unit for converting the power of the DC power source into a voltage and providing the voltage as a load;

A control scheme determining unit determining a control scheme according to an increase or decrease in the magnitude of an output voltage and an output current of the voltage converter and an output voltage of the voltage converter;

A PV modeling unit for generating a reference voltage or a reference current by using a predetermined PV modeling technique according to the control method determined by the control method determining unit; And

A main controller for controlling an output voltage or an output current of the voltage converter by comparing the reference voltage or the reference current provided by the PV modeler with the output voltage or the output current of the voltage converter,

And a hysteresis control unit.

In one embodiment of the present invention, the control method determined by the control method determination unit is one in which the PV modeling unit generates the reference voltage by the predetermined PV modeling technique, and the main control unit performs the voltage conversion A voltage control method of controlling the voltage conversion unit so that a negative output voltage becomes substantially the same; And a current control method in which the PV modeling unit generates the reference current by the predetermined PV modeling technique and the main control unit controls the voltage converting unit so that the reference current and the output current of the voltage converting unit become substantially equal to each other .

In one embodiment of the present invention, the control scheme determining unit compares the output current of the voltage converter with a predetermined maximum power operation current according to the IV characteristic curve to perform one of the voltage control scheme and the current control scheme Time control method.

In one embodiment of the present invention, when the output current of the voltage conversion unit has a value smaller than the maximum power operation current, the control method determination unit determines the control method at the start-up operation as the voltage control method, The control method at the start-up operation can be determined to be the voltage control method when the output current of the negative output current is smaller than the maximum power operation current.

In one embodiment of the present invention, the control method determination unit determines whether or not a predetermined first set voltage having a value smaller than the maximum power operation voltage by the IV characteristic curve and a predetermined second set voltage having a value larger than the maximum power operation voltage The control method during operation can be determined according to the change of the voltage supplied to the load based on the set voltage.

In one embodiment of the present invention, when the output voltage of the voltage converting unit is decreased and becomes less than the first set voltage during the operation of the voltage control scheme, the control scheme determining unit switches the control scheme by the current control scheme, When the output voltage of the voltage converter increases during the operation of the current control method and exceeds the second set voltage, the control method can be switched by the voltage control method.

According to another aspect of the present invention,

And a voltage conversion unit for converting the power of the direct current power source and the direct current power source into a load to provide the load as a load. The control unit of the PV simulation apparatus for outputting the output of the PV array composed of the PV cells according to a predetermined IV characteristic curve of the PV cell, In the method,

Comparing a predetermined maximum power operation current with an output current of the voltage conversion unit and the I-V characteristic curve at the start of the PV simulation apparatus;

Determining and operating a control method at startup of the PV simulation apparatus according to a result of the comparing step; And

A predetermined first set voltage having a value smaller than the maximum power operation voltage by the IV characteristic curve and a preset second set voltage having a value larger than the maximum power operation voltage The step of switching the control method during operation

And a control method of the PV simulation apparatus.

In one embodiment of the present invention, the control method includes: a voltage control method of generating a reference voltage by a predetermined PV modeling technique and controlling the voltage conversion unit so that the reference voltage and the output voltage of the voltage conversion unit become substantially the same; ; And a current control method of generating a reference current by the predetermined PV modeling technique and controlling the voltage converting unit so that the reference current and the output current of the voltage converting unit become substantially equal to each other.

In one embodiment of the present invention, the operating step may include comparing one of the voltage control method and the current control method with the output current of the voltage converting part by a predetermined maximum power operating current according to the IV characteristic curve, It can be determined as a control method when the simulation apparatus is started.

In one embodiment of the present invention, the operating step determines the control method at the start of the PV simulation apparatus by the voltage control method when the output current of the voltage converting unit has a value smaller than the maximum power operation current, When the output current of the voltage conversion unit has a value smaller than the maximum power operation current, the control method at the start of the PV simulation apparatus can be determined by the voltage control method.

In one embodiment of the present invention, the switching may include: comparing an output voltage of the voltage converter with the first set voltage and the second set voltage; Switching the control method of the PV simulation apparatus to the current control method when the output voltage of the voltage conversion unit decreases and becomes less than the first set voltage during the operation of the voltage control method; And switching the control scheme of the PV simulation apparatus to the voltage control scheme when the output voltage of the voltage converter increases and exceeds the second set voltage during the operation of the current control scheme.

According to the present invention, it is possible to secure stable output characteristics and excellent dynamic characteristics in the entire operation period of the PV simulation apparatus. In particular, according to the present invention, when the output voltage of the PV simulation apparatus is between a first set voltage which is a lower limit voltage and a second set voltage which is an upper limit voltage (V _{MP_L} <V _PV <V _{MP_H} ) (V _PV <V _{MP_L} or V _PV > V _{MP_H} ) is deviated from the first set voltage which is the lower limit voltage or the second set voltage which is the boundary voltage by changing the output voltage of the PV simulation apparatus, The control method that provides a stable output or the control method that provides excellent dynamic characteristics in the corresponding section can ensure stable output characteristics and excellent dynamic characteristics.

1 is a configuration diagram illustrating a PV simulation apparatus to which hysteresis control is applied according to an embodiment of the present invention.
2 is a diagram for explaining a voltage control method applied to a control method of a conventional PV simulation apparatus.
3 is a diagram for explaining a current control method applied to a control method of a conventional PV simulation apparatus.
4A and 4B are output IV characteristic curves of the PV simulation apparatus according to the voltage control method and the current control method shown in FIGS. 2 and 3, respectively.
5 (a) and 5 (b) are dynamic characteristic results of the PV simulation apparatus using the voltage control method and the current control method shown in Figs. 2 and 3, respectively.
FIG. 6 is a diagram illustrating a concept of a control technique based on a hysteresis control period applied to an embodiment of the present invention.
7 is a flowchart showing a control method of a PV simulation apparatus according to an embodiment of the present invention.
8 is an IV and PV characteristic curve obtained through experiments on a PV simulation apparatus and a control method thereof according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In addition, in describing the present invention, the defined terms are defined in consideration of the functions of the present invention, and they may be changed depending on the intention or custom of the technician working in the field, so that the technical components of the present invention are limited It will not be understood as meaning.

1 is a configuration diagram illustrating a PV simulation apparatus to which hysteresis control is applied according to an embodiment of the present invention.

1, a PV simulation apparatus to which hysteresis control according to an embodiment of the present invention is applied includes a DC power source 11, a voltage converting unit 12, a control method determining unit 13, a PV modeling unit 14, And a main control unit 15.

The direct current power source 11 is a power source device for outputting a direct current voltage and current, and a normal battery can be employed.

The voltage converting unit 12 is a DC-DC converter that appropriately converts the voltage of the DC power supplied from the DC power supply 11 and outputs the converted voltage. The output voltage and the output current of the voltage converter 12 can be controlled to have a value corresponding to the I-V curve of the predetermined PV cell. To this end, a control method determination unit 13, a PV modeling unit 14, and a main control unit 15, which will be described later, are provided.

1 includes a DC link implemented by a capacitor C _dc connected in parallel to a DC power source 11, a Buck converter of a two-leg-interleaved structure connected to a DC link, and a buck converter And a direct current (DC) filter that converts the DC voltage to a DC voltage. The output of the buck converter is controlled by PWM switching control to simulate the output of the PV array.

The buck converter shown in Fig. 1 operates in an interleaved form using a standard H bridge stack, so that the development is simple and the size of the filter inductor can be reduced. In the example of FIG. 1, the buck converter of the voltage converter is a parallel connection of three buck converters of two leg-interleaved structure, and can simulate the operation of the PV array having multiple maximum power points. The Buck converter has better efficiency than the linear converter. However, since the switching ripple component is contained in the voltage and current of the DC output side, a high performance smoothing DC filter is required to ensure the current and voltage accuracy according to the EN50530 specification.

Particularly, since the input stage of the power conditioning system applied to the load 21 of the PV simulation apparatus has a very large capacity smoothing capacitor, it is preferable to implement the output stage of the buck converter in the voltage converter 12 with an LC filter structure It is preferable to implement the LCL filter (L _f1 , L _f2 -C _f -L _g ). Since the filter capacitor of the LC filter and the input stage smoothing capacitor of the PCS are connected and operated in parallel, the dynamic characteristics of the PV simulation apparatus are influenced by the connection of the power conditioning system. In the initial operation, This is because a problem of inrush current may occur. It is therefore desirable to provide an inductor for decoupling to separate the filter capacitor of the LC filter and the input stage smoothing capacitor of the PCS.

The control system determination unit 13 determines the control method of the PV simulation apparatus according to the increase and decrease of the output voltage and the output current of the voltage converter 12 and the output voltage of the voltage converter 12.

The control system determined by the control system determination unit 13 includes a voltage control system that controls the output voltage of the voltage converter 12 to match the reference voltage determined by the PV array characteristics, And a current control scheme for controlling the output current to match the reference current determined by the PV array characteristics. A more detailed description of the voltage control method and the current control method will be described later.

The PV modeling unit 14 may generate the reference voltage or the reference current using a predetermined PV modeling technique according to the control method determined by the control method determining unit 13. [ For example, when the control method determined by the control method determination unit 13 is a voltage control method, the PV modeling unit 14 generates and outputs a reference voltage. The technique of generating the reference voltage by the PV modeling unit 14 can be applied to a reference voltage generation algorithm known in the art. When the control method determined by the control method determining unit 13 is a current control method, the PV modeling unit 14 generates and outputs a reference current. The technique of generating the reference current by the PV modeling unit 14 can be applied to a reference current generation algorithm known in the art. A more detailed description of the reference voltage and reference current generation algorithm applied to the PV modeling unit 14 will be described later.

The main control unit 15 receives the reference voltage or the reference current inputted from the PV modeling unit 14 and receives the output voltage or the output current of the voltage converting unit 12 and compares the values with each other, And outputs a control signal capable of controlling the voltage conversion section 12 so that the output current becomes substantially equal to the reference voltage or outputs a control signal capable of controlling the voltage conversion section 12 such that the output current becomes substantially equal to the reference current. can do. For example, the main controller 15 may be implemented as a PI controller that performs a subtracter for calculating a difference between an output voltage and a reference voltage or a difference between an output current and a reference current, and a subtracter for eliminating the difference .

The control signal output from the main control unit 15 is input to the PWM driving unit 16 and the PWM driving unit 16 can PWM drive the switch provided in the voltage conversion unit 12 according to the control signal.

The PV simulation apparatus and method using the hysteresis control according to the embodiment of the present invention can calculate the magnitude of the voltage and current (the output voltage and the output current of the voltage converting unit 12) output to the power conditioning system as the load 21 And the control method determination unit 13 determines whether or not the voltage control method according to the result of comparison between the preset first set voltage and the second set voltage based on the maximum power operation current and the IV characteristic curve by the IV characteristic curve of the predetermined PV cell And a current control method to control the PV simulation apparatus.

FIG. 2 is a diagram for explaining a voltage control method applied to a control method of a PV simulation apparatus according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating a method of controlling a PV simulation apparatus according to an embodiment of the present invention Current control method.

2, in an embodiment of the present invention in a voltage control method, a load side output current I _PV is detected and a reference voltage V _ref based on an IV characteristic curve of a predetermined PV cell is set as a control target And controls the voltage across the capacitor (C _f ) (V _PV ). A capacitor (C _f), the both-end voltage (V _PV) correspond to the output voltage of the voltage converting part 12 is output to the load.

Also, reference to Figure 3, one embodiment of the present invention in the current control method has a capacitor (C _f) a reference current (I _ref) based detects the both-end voltage (V _PV) in the IV characteristic curve of the preset PV cells To control the output current I _PV . The current detected in the current control method shown in FIG. 3, that is, the current whose magnitude is controlled can be the current I _L of the filter inductor L _f1 or L _F2 . This filter capacitor (C _f) roneun therefore flows only the ripple current of the AC component through the control of the DC component current of the filter inductor (L _f1 or L _F2) it is possible to effectively control the output current (I _PV), at the same time the filter inductor This is because the resonance generated in the LC filter can be suppressed by using the current (I _L ) for the active damping control. Since the filter inductor current I _L has a linear relationship with the output current of the voltage converting unit 12, the inductor current I _L may correspond to the output current of the voltage converting unit 12.

In the PV simulation apparatus shown in FIGS. 2 and 3, the PV modeling unit 14 can output the reference voltage and the reference current, respectively, using the voltage equations and the current equations, which are mathematical expressions of the PV array. For example, voltage equations and current equations of a single diode equivalent circuit model of a PV cell of Wagner are known [C. Bendel and A. Wagner, "Photovoltaic measurement relevant to the energy yield" in Proc. WCPEC-3 World Conference on Photovoltaic Energy Conversion, Osaka, Japan, 11-18 May 2003, Pr. No. 7P-B3-09, pp 1-4].

The voltage and current equations of a single diode equivalent circuit model of this Wagner PV cell are obtained as follows.

[Formula 1]

(With k ₁ = -5.411, k ₂ = 6.450, k ₃ = 3.417, k ₄ = -4.422)

[Formula 2]

[Formula 3]

[Formula 4]

Here, the reference voltage V _ref and the reference current I _ref are determined as follows.

[Formula 5]

[Formula 6]

Where I _sc is the current at the short-circuit operating point, I ₀ is the diode saturation current, R _pv is the photovoltaic resistance of Wagner and V _t is the thermal voltage of Wagner.

The inventor of the present invention conducted an experiment on a PV simulation apparatus by applying a voltage control method and a current control method based on FIG. 2, FIG. 3, and Equations 1 to 6.

Table 1 below shows the specifications of PV array constructed by applying the parameters of the thin film type PV cell given in IEC EN50530, which is the standard of PV efficiency standard. To simulate the PV array corresponding to this specification, the PV simulation device is implemented, And the current control method are the same as those shown in FIG. 4 and FIG.

Item value Maximum power (P _MPP ) 614.09 [W] The maximum power point voltage (V _MPP ) 239.88 [V] Maximum power point current (I _MPP ) 2.56 [A] The short circuit current (I _sc ) 2.79 [A] Open circuit voltage (V _oc ) 300 [V]

4A and 4B are output I-V characteristic curves of the PV simulation apparatus according to the voltage control method and the current control method shown in FIG. 2 and FIG. 3, respectively. Particularly, FIG. 4 shows the results of experiments on the steady state operation characteristics of the PV simulation apparatus corresponding to the I-V characteristic curve of the PV array by applying an electronic load to the PV simulation apparatus of the two control methods. 4 (a) and 4 (b) show the I-V characteristic curves of the PV simulation apparatus using the waveforms of the experimental results using the voltage control method and the current control method, respectively.

As shown in FIG. 4 (b), when the current control method is applied, the I-V characteristic curve of the PV simulation device follows the characteristic curve of the PV array model relatively well in the entire operation region.

However, as shown in FIG. 4 (a), when the voltage control method is applied, the characteristic curve of the PV array model from the open circuit operation point (V _OC ) to the maximum power operation point (V _MP ) The characteristics are unstable from the maximum power operation point (V _MP ) to the short circuit operation point (I _SC ) portion.

This result is analyzed because the output voltage reference value given in the I-V curve of the PV array model is greatly changed with respect to the small ripple component error of the output stage detection current when the voltage control method is applied.

5 (a) and 5 (b) are dynamic characteristic results of the PV simulation apparatus using the voltage control method and the current control method shown in Figs. 2 and 3, respectively. In particular, the lower curve in FIG. 5 shows the output current waveform of the PV simulation device, and the upper curve shows the output voltage waveform of the PV simulation device. 5 (a) and 5 (b) show the waveforms of the dynamic characteristics of the PV simulation apparatus when the voltage control method and the current control method are applied, respectively. In both graphs, the time axis is the same. 5, when the voltage control method is applied, the output voltage and the output current of the PV simulation device are rapidly changed step by step, whereas the output voltage and the output current of the PV simulation device are relatively It can be confirmed that it responds slowly.

In conclusion, when the voltage control method is applied, the PV simulation device has good dynamic characteristics, while the stable operation period is limited from the open circuit operation point (V _OC ) to the maximum power operation point (V _MP ) It can be confirmed that the PV simulation device is relatively stable in the entire operation period although the dynamic characteristics are relatively low.

In view of the output characteristics of the voltage control method and the current control method, an embodiment of the present invention can satisfy the operating characteristics of the PV simulation apparatus proposed by EN50530 of IEC by applying only the advantages of the voltage control method and the current control method A PV simulation apparatus and a control method thereof using hysteresis control are proposed. In the embodiment of the present invention, stable operation is ensured in the entire operation section, and operation with high dynamic characteristics is possible in the section between the open circuit operation point (V _OC ) and the maximum power operation point (V _MP ).

FIG. 6 is a diagram illustrating a concept of a control technique based on a hysteresis control period applied to an embodiment of the present invention. In Fig. 5, solid line arrows indicate the sections that are operated by the voltage control method, and dotted arrows indicate the sections that are operated by the current control method. The output current and voltage of the PV simulator are operated at a point on the I-V curve indicated by the bold solid line in Fig.

6, in one embodiment of the present invention, a predetermined first set voltage V _{MP_L} having a value smaller than the maximum power voltage V _MP in the predetermined IV curve of the PV cell and the predetermined first set voltage V _{MP -} A preset second set voltage V _{MP_H} having a value larger than the maximum power operation voltage is determined and the output voltage of the voltage converter 12 input to the load is detected to determine the voltage control method and / You can control the PV simulation device by selecting the current control method.

The operation and effect of the PV simulation apparatus and the control method thereof according to an embodiment of the present invention will be described in more detail with reference to the accompanying drawings. A detailed description of a control method of a PV simulation apparatus according to an embodiment of the present invention can be made through the following actions and effects.

 7 is a flowchart showing a control method of a PV simulation apparatus according to an embodiment of the present invention.

7, when the operation of the PV simulation apparatus to which the hysteresis control is applied according to the embodiment of the present invention is started, the control method determination unit 13 compares the output current I _PV of the voltage conversion unit 12 with the maximum The power operation current I _MP is compared (S11). In step S11, when the output current I _PV of the voltage converting unit 12 has a value smaller than the maximum power operating current I _MP , the control system determining unit 13 determines the control system at the start- (S12). When the output current of the voltage converter 12 has a value larger than the maximum power operation current (I _MP ), the control method can be determined as the current control method at the start-up operation (S 12).

The output current I _PV of the voltage converting unit 12 in step S11 does not mean only the current directly input to the load 21 but also the amount of current It should be understood that it means all possible currents.

2, the PV modeling unit 14 generates a reference voltage V _ref by a predetermined PV modeling technique and outputs the reference voltage V _ref to the main The control unit 15 can control the voltage converting unit 12 such that the reference voltage V _ref and the output voltage of the voltage converting unit 12 become substantially equal to each other.

During the operation of the voltage control method (S12), the control system determination unit 13 compares the output voltage V _PV of the voltage conversion unit 12 with the preset first set voltage V _{MP_L} (S13 , The control method is switched to the current control method when the resistance value of the load gradually decreases and the output voltage V _PV of the voltage converter 12 becomes less than the preset first set voltage V _{MP_L} (S14) . That is, when the resistance value of the load applied to the output terminal of the voltage converter 12 of the PV simulation apparatus decreases, the output current I _PV rises and the output voltage V _PV rises on the IV characteristic curve. The output current I _PV and the output voltage V _PV further move to the left on the IV characteristic curve to reach the maximum power operation point V _MP when the resistance value of the load applied to the output terminal of the voltage converter 12 continuously decreases. And reaches the first set voltage V _{MP_L} which is the lower limit voltage of the hysteresis control period. When the output voltage of the voltage converter 12 becomes smaller than the first set voltage (V _PV < V _{MP_L} ), the control scheme determiner 13 _{switches the} control scheme to the current control scheme S14.

3, the PV modeling unit 14 generates the reference current I _ref by a predetermined PV modeling technique, and _{outputs the} reference current I _ref to the main The control unit 15 can control the voltage conversion unit 12 such that the reference current I _ref and the output current of the voltage conversion unit 12 become substantially equal.

During the operation of the current control method (S14), the control system determination unit 13 compares the output voltage V _PV of the voltage conversion unit 12 with the preset second set voltage V _{MP_L} (S15 ), When the resistance value of the load gradually increases due to some cause and the output voltage V _PV of the voltage converter 12 exceeds the predetermined second set voltage V _{MP_H} , (S12).

That is, when the resistance value of the load applied to the output terminal of the voltage conversion section 12 increases for some reason during the operation in the current control method (S14), the output current I _PV falls on the IV characteristic curve and the output voltage V _PV ) is increased. The output current I _PV and the output voltage V _PV further move to the right on the IV characteristic curve to reach the maximum power operation point V _MP when the resistance value of the load applied to the output terminal of the voltage converter 12 continuously increases. And reaches the second set voltage V _{MP_H} which is the upper boundary voltage of the hysteresis control period. When the output terminal voltage of the voltage converter 12 exceeds the second set voltage (V _PV > V _{MP_H} ), the control scheme determiner 13 switches the control scheme to the voltage control scheme S12.

8 is an I-V and P-V characteristic curve obtained through experiments on a PV simulation apparatus and a control method thereof according to an embodiment of the present invention.

8, according to the PV simulation apparatus and the control method thereof according to the embodiment of the present invention, the output current and the output voltage can be stably outputted, and the predetermined IV characteristic curve of the PV array can be generally well- You can see that you follow.

As described above, in the embodiment of the present invention, when the output voltage of the PV simulation apparatus (the output voltage of the voltage converting unit 12) is between the first set voltage which is the lower limit voltage and the second set voltage which is the upper limit voltage V _{MP_L} <V _PV <V _{MP_H),} it does not switch the control method, when the output voltage of the voltage converter 12 changes beyond the first predetermined voltage or a second predetermined voltage, (V _PV <V _{MP_L} or V _PV > V _{MP_H} ) control method is switched to ensure stable output characteristics. That is, when the output voltage of the voltage converting unit 12 is low, a stable output can be provided by selecting the current control method. When the output of the voltage converting unit 12 is high, . Further, if the lower boundary voltage of the first setting voltage is set to (V _{MP_L)} and the upper bound of the second voltage setting voltage (V _{MP_H)} each V _MP -10% and + 10% _MP V V as specified in the IEC EN50530 _In the operation period of _MP ± 10%, the output of the stable IV characteristic can be obtained without changing the control method of the PV simulation device.

Although the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present invention should not be limited to the embodiments described, but should be determined by the scope of the following claims and equivalents thereof.

11: DC power supply 12: Voltage conversion section
13: Control method determination unit 14: PV modeling unit
15: main control unit 16: PWM driving unit

Claims (11)

A PV simulation apparatus for outputting and outputting an output of a PV array made up of the PV cell according to a predetermined IV characteristic curve of the PV cell,
DC power supply;
A voltage converting unit for converting the power of the DC power source into a voltage and providing the voltage as a load;
A control scheme determining unit determining a control scheme according to an increase or decrease in the magnitude of an output voltage and an output current of the voltage converter and an output voltage of the voltage converter;
A PV modeling unit for generating a reference voltage or a reference current by using a predetermined PV modeling technique according to the control method determined by the control method determining unit; And
And a main controller for controlling an output voltage or an output current of the voltage converter by comparing the reference voltage or the reference current provided by the PV modeler with the output voltage or the output current of the voltage converter,
Wherein the control method determining unit determines the control method based on the predetermined first set voltage having a value smaller than the maximum power operating voltage by the IV characteristic curve and a preset second set voltage having a value larger than the maximum power operating voltage, A PV simulation device applying hysteresis control that determines the control method during operation according to the change of supplied voltage. The method according to claim 1,
Wherein the control method determined by the control method determination unit comprises:
A voltage control method in which the PV modeling unit generates the reference voltage by the predetermined PV modeling technique and the main control unit controls the voltage converting unit so that the reference voltage and the output voltage of the voltage converting unit become substantially equal to each other; And a current control method in which the PV modeling unit generates the reference current by the predetermined PV modeling technique and the main control unit controls the voltage converting unit so that the reference current and the output current of the voltage converting unit become substantially equal to each other Wherein the hysteresis control is applied to the PV simulation apparatus. 3. The method of claim 2,
Wherein the control method determining unit compares the output current of the voltage converting unit with a predetermined maximum power operating current according to the IV characteristic curve and determines one of the voltage control method and the current control method as a control method at the start- A PV simulation device to which hysteresis control is applied. The method of claim 3,
Wherein the control method determining unit determines the control method at the start-up operation as the voltage control method when the output current of the voltage converting unit has a value smaller than the maximum power operating current, The control method is determined as the current control method when the operation is started. delete The method according to claim 1,
Wherein the control mode determination unit switches the control mode according to the current control mode when the output voltage of the voltage conversion unit decreases and becomes less than the first set voltage during the operation of the voltage control mode, And when the output voltage of the converter increases to exceed the second set voltage, the control method is switched by the voltage control method. And a voltage conversion unit for converting the power of the direct current power source and the direct current power source into a load to provide the load as a load. The control unit of the PV simulation apparatus for outputting the output of the PV array composed of the PV cells according to a predetermined IV characteristic curve of the PV cell, In the method,
Comparing an output current of the voltage conversion unit with a predetermined maximum power operation current by the IV characteristic curve when the PV simulation apparatus is started;
Determining and operating a control method at startup of the PV simulation apparatus according to a result of the comparing step; And
A predetermined first set voltage having a value smaller than the maximum power operation voltage by the IV characteristic curve and a preset second set voltage having a value larger than the maximum power operation voltage The step of switching the control method during operation
And a control unit for controlling the PV simulation apparatus. 8. The method of claim 7,
The control method includes: a voltage control method of generating a reference voltage by a predetermined PV modeling technique and controlling the voltage converting unit so that the reference voltage and the output voltage of the voltage converting unit become substantially equal; And a current control method of generating a reference current by the predetermined PV modeling technique and controlling the voltage converter so that the reference current and the output current of the voltage converter become substantially equal to each other Control method. 9. The method of claim 8,
Wherein the operating step compares the output current of the voltage conversion unit with a predetermined maximum power operation current according to the IV characteristic curve to control one of the voltage control method and the current control method when the PV simulation apparatus is started Wherein the control unit is configured to determine whether the PV is in a predetermined state or not. 10. The method of claim 9,
Wherein when the output current of the voltage conversion unit has a value smaller than the maximum power operation current, the control unit determines the control method for starting the PV simulation apparatus by the voltage control method, Wherein the control method for the start of the PV simulation apparatus is determined to be the current control method when the PV simulation apparatus has a value larger than the maximum power operation current. 9. The method of claim 8,
Comparing the output voltage of the voltage converter with the first set voltage and the second set voltage;
Switching the control method of the PV simulation apparatus to the current control method when the output voltage of the voltage conversion unit decreases and becomes less than the first set voltage during the operation of the voltage control method; And
And converting the control method of the PV simulation apparatus into the voltage control method when the output voltage of the voltage conversion unit increases and exceeds the second set voltage during operation of the current control system / RTI &gt;

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