KR101750224B1 - Apparatus and method for controlling transfer of inverter - Google Patents

Apparatus and method for controlling transfer of inverter Download PDF

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KR101750224B1
KR101750224B1 KR1020160032795A KR20160032795A KR101750224B1 KR 101750224 B1 KR101750224 B1 KR 101750224B1 KR 1020160032795 A KR1020160032795 A KR 1020160032795A KR 20160032795 A KR20160032795 A KR 20160032795A KR 101750224 B1 KR101750224 B1 KR 101750224B1
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South Korea
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grid
control
signal
inverter
integral controller
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KR1020160032795A
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Korean (ko)
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김윤성
박재광
이병국
안정훈
안효민
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주식회사 동아일렉콤
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02J2003/388—
    • H02M2001/0003—

Abstract

The present invention sets the control region in consideration of the power range required for the system and the voltage range in which the divergence is suppressed, and limits the output of the inverter within this control region, thereby preventing divergence which may have a negative influence on the switching process. The present invention relates to an inverter switching control apparatus capable of improving the efficiency of the inverter. In a system-connected inverter operated in a grid-connected mode connected to a grid or in a single-operated mode in which a connection with the grid is disconnected, an apparatus for controlling switching between a grid-connected mode and a single- The control range is set to be narrower than the voltage range that is wider than the power range required for the system in the grid-connected mode and in which the divergence does not occur in the single-operation mode Can be set.

Figure R1020160032795

Description

[0001] APPARATUS AND METHOD FOR CONTROLLING TRANSFER OF INVERTER [0002]

More particularly, the present invention relates to a switching control apparatus for a three-phase grid-link inverter and a control method thereof. More particularly, the present invention relates to a switching control apparatus for setting a control region in consideration of a power range required for a system and a voltage range in which divergence is suppressed, The present invention relates to an inverter switching control apparatus and a control method thereof, which can prevent a divergence which may be adversely affected in a switching process by limiting the switching operation of the inverter to a region, and improve the stability of the system.

Conventional grid-connected inverters block and protect the system through anti-islanding operation in order to secure the safety of the grid system in case of a system accident.

Recently, the use of grid-connected inverters for various applications (ESS, smart grid, etc.) has been expanded to a complex structure in which emergency load (critical load) devices are connected rather than simple grid connection conditions.

1 shows a general structure of a grid-connected inverter according to the present invention. In order to cope with the emergency load system, the inverter simultaneously supplies power to the grid connection operation and the emergency load side in the normal operation period. In the event of a system fault, the system is normally disconnected from the line, and the emergency load side is continuously supplied with power.

At this time, the normal wiring interconnection of the system is performed primarily by the external recloser opening of the grid interconnection system, and the inverter is completely disconnected from the system through the STS open included in the grid interconnection inverter device. This STS prevents transient problems such as transient currents due to the phase difference (voltage difference) between the grid voltage and the single operation output voltage because the system is instantaneously restored in a situation where the inverter operates alone to supply the emergency load.

On the other hand, the emergency load composed of the STS and the inverter side is supplied with power through the output of the inverter.

That is, the inverter operates as a current control type inverter in the normal mode, and after the system phase information disappears due to a system fault, it should be switched to the voltage control type inverter operation with the set output range.

The inverter uses a DC power source such as a battery as input. In the grid-connected normal operation mode, the phase information of the system is measured and the current control is performed to control the output power as much as possible. The current control is used to adjust the power of the system whenever possible.

On the other hand, when a system accident occurs, it is stably blocked with the system through the external recloser and internal STS to prevent the transient problem due to the system back-up. In order to continuously supply power to the emergency load, Continuously. At this time, since the system that holds the voltage of the emergency load is shut off due to the problem, the inverter essentially uses the voltage control with the voltage range within the range required for the emergency load.

In this connection, Fig. 2 schematically shows a mode in which the grid-connected inverter operates according to the state of the system.

Referring to FIG. 2, as in mode 1, the Recloser and the STS are ON at the system normal, and the inverter control is proceeded by the current control method in the normal grid-connected state.

Next, when a grid fault mode occurs in which the AC-Grid is faulty as in mode 2, the external recloser is turned OFF (open), and the STS is still in an unstable state. At this time, the system is required to be in a stand-alone state but the inverter still operates in the current control state. In this interval, the transient condition is entered in which the current control is changed to the voltage control.

Next, the mode 3 is a period in which the control switching of the inverter is completed in the state of the mode 2, and operates under voltage control suitable for the single operation state.

Next, mode 4 is a condition in which the system accident state of mode 3 is resolved or changed and changed to the normal system mode. AC-Grid is a normal grid connection state. The external Recloser is ON and ready to be connected to the inverter. However, the internal STS remains OFF because it can not grasp the system steady state yet. The control method also maintains the voltage control method and enters the transient condition by the voltage control to the current control.

Mode 1 indicates a state in which the control change-over process is completed in mode 4 and the normal current control and the grid connection are returned.

That is, in the case of a grid-connected inverter using such an emergency load, a control switching period in which the current control and the voltage control are changed as in the mode 2 and the mode 4 is essentially required. In this case, the inverter output is in an unstable state .

In order to solve this transient switching control, conventionally, operating parameters required for the switching period are obtained through a separate measuring circuit. The measured voltage information was measured at the filter located between the grid and the inside of the inverter.

However, according to this conventional technique, an additional measuring circuit is required, and the structure of the filter circuit must be optimized in order to improve the performance of the transfer algorithm, not the performance of the filter itself, so that the design flexibility is lowered and the system side inductor and inverter side The inductor ratio must be maintained at a certain level, and the filter design has a limitation.

Korean Patent Publication No. 10-1178393 Korean Patent Publication No. 10-2004-0099202

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a control method and a control method of an inverter, The present invention has been made to provide a switching control apparatus and control method for an inverter that can prevent a divergence that may adversely affect the system and enhance the stability of the system.

Specifically, the present invention provides a switching control device of an inverter, which can sufficiently improve a transient problem by setting the boundary of the control area sufficiently wide to achieve a control target in the grid-connected mode and at the same time sufficiently small to prevent divergence, To provide it to the public.

It is another object of the present invention to provide a switching control device of an inverter which can ensure stable operation in a switching section without additional measuring circuit and which is more economical and less restrictive in terms of system design.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. It can be understood.

The present invention relates to an apparatus for controlling switching between a grid connection mode and a single operation mode in a grid connection inverter operated in a grid connection mode connected to a grid or in a single operation mode in which connection with the grid is disconnected, Wherein the switching control device sets a predetermined control area and limits the output of the grid-connected inverter to the set control area, and the control area controls the grid-connected inverter in the grid- May be set to be narrower than a voltage range that is wider than the power range required for the system and does not cause divergence in the single operation mode.

A forward compensator for setting a target electric signal to be output from the grid-connected inverter; And a proportional integral controller for compensating an actual electrical signal and an error of the target electrical signal.

The proportional-plus-integral controller may further include an inverse proportional-integral controller for receiving the Q-axis component of the actual electric signal, performing proportional control and integral control, and outputting the result; And a D-axis component of the measured electrical signal and a D-axis component of the target electrical signal, performing proportional control and integral control on the D-axis component of the input actual-side electrical signal and the D- And an error-proportional integral controller for outputting the resultant value.

The inverse proportional integral controller further includes an invertor for inverting a Q-axis component of the input actual electric signal, wherein the error proportional integral controller calculates a difference between a D axis component of the input actual electric signal and a D And a signal subtraction unit for generating a difference signal of the axis component.

A first limiter for limiting a magnitude of a Q-axis component (V q, FF ) of a signal output from the deflector to a predetermined range; And a second limiter for limiting the magnitude of the D-axis component (V d, FF ) of the signal output from the deflector to a preset predetermined range.

A third limiter for limiting the magnitude of the signal output from the error-proportional-plus-integral controller to a predetermined range; And a fourth limiter for limiting the magnitude of the signal output from the inverse proportional integral controller to a predetermined range.

A first signal summation unit for summing the signal output from the second limiter and the signal output from the third limiter to generate an inverter-side D-axis target voltage (V d, ref, inv ); And a second signal summation unit for generating an inverter Q-axis target voltage ( Vq, ref, inv ) by summing the signal output from the first limiter and the signal output from the fourth limiter.

A DQ inverse transformer for receiving and DQ-inverting the inverter-side D-axis target voltage generated in the first signal summation unit and the inverter-side D-axis target voltage generated in the second signal summation unit; And a PWM generator for receiving the inversely converted signal from the DQ inverse transformer and generating a PWM signal for generating an AC signal.

Also, it can be set using the forward compensator region determined by the forward compensator and the proportional integral controller region determined by the proportional integral controller.

Also, the control area may be defined as a combination of the deflection compensator area and the area generated by superimposing the proportional integral controller area on all parts of the deflection compensator area.

According to another aspect of the present invention, there is provided a method of controlling switching between the grid-connected mode and the single-operation mode in a grid-connected inverter connected to a grid or a single-run mode in which connection with the grid is disconnected, According to an aspect of the present invention, there is provided a switching control method including: a first step of setting a predetermined control area of the switching control device; And a second step of limiting the output of the grid-connected inverter to the set control area, wherein the control area set in the first step is wider than the power range required for the system in the grid- Is narrower than the voltage range in which divergence does not occur in the operation mode.

Further, the first step may include: setting a target electric signal to be output from the grid-connected inverter by the deflector; And the proportional integral controller may compensate for the error of the actual electrical signal and the target electrical signal.

The proportional plus integral controller may further include an inverse proportional integral controller for receiving the Q-axis component of the actual electric signal, performing proportional control and integral control, and outputting a result of the proportional control and integral control, An error component proportional integral controller for receiving the D axis component of the electric signal and performing proportional control and integral control on the D axis component of the input actual electric signal and the D axis component of the target electric signal, Lt; / RTI >

The present invention sets the control region in consideration of the power range required for the system and the voltage range in which the divergence is suppressed, and limits the output of the inverter within this control region, thereby preventing divergence which may have a negative influence on the switching process. It is possible to provide the user with the switching control device of the inverter and the control method thereof which can be improved.

Specifically, the present invention provides a switching control device of an inverter, which can sufficiently improve a transient problem by setting the boundary of the control area sufficiently wide to achieve a control target in the grid-connected mode and at the same time sufficiently small to prevent divergence, .

Also, according to the present invention, it is possible to guarantee a stable operation in a switching section without an additional measuring circuit, and to provide a switching control device of an inverter which is more economical and less restrictive in terms of system design.

It should be understood, however, that the effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned may be clearly understood by those skilled in the art to which the present invention belongs It will be possible.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, It should not be construed as limited.
1 shows a general structure of a grid-connected inverter according to the present invention.
FIG. 2 schematically shows a mode in which the grid-connected inverter operates according to the state of the system.
3 is a block diagram of an inverter switching control device that can be implemented according to the present invention.
4A to 4C show a control locus for explaining the setting of the control area according to the present invention.
Figures 5A and 5B schematically illustrate control areas that may be applied to the present invention.
Figure 6 shows an embodiment of a control area set in accordance with Figure 5a.
7 shows a simulation result waveform for the ablation control apparatus of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. In addition, the embodiment described below does not unduly limit the content of the present invention described in the claims, and the entire structure described in this embodiment is not necessarily essential as the solution means of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is directly connected to the other part, do. Also, to include an element does not exclude other elements unless specifically stated otherwise, but may also include other elements.

In general, the grid-connected inverter operates as a current controller in grid-connected mode and as a voltage controller in stand-alone mode. In case of switching between grid-connected mode and single-operation mode due to a system accident, the grid-connected inverter can not recognize it immediately, so that a very large transient state may occur in the load voltage depending on the output power and the load condition.

Conventionally, indirect current control is a typical method for controlling such a transfer. Indirect current control indirectly controls the magnitude and direction of the output current of the inverter indirectly by controlling the magnitude and phase of the capacitor voltage of the LCL filter according to the direction and magnitude of the current.

In the case of indirect current control, since the constant capacitor voltage is controlled, even if a system fault occurs, there is no transient state according to the switching state of the load voltage.

However, since the indirect current control algorithm uses the capacitor voltage value of the LCL filter, there is a limitation that the LCL filter must be used. In addition, the optimized filter for the intrinsic purpose of the LCL filter to minimize THD and current ripple must be designed to have a larger inverter side inductor (L i ) than the system side inductor (L g ) are to be designed such optimized filter as opposed to the grid-side inductor (L g) is larger than the inverter-side inductor (L i). These limitations must be designed so that the sum of the total inductance of the ESS using the indirect current control method is larger to satisfy the same THD specification. That is, it can cause a larger filter size and weight. In addition, additional devices and resources are required, including the addition of three voltage sensors and three ADC ports. Furthermore, the indirect current control algorithm can not be applied to the modular ESS because the parallel operation in the single operation is not considered at all.

This indirect current control algorithm is difficult to select and optimize the filter type, and it is difficult to extend it to parallel algorithms while requiring additional devices. Therefore, it is possible to relax the restriction on the use of the filter, And the development of a grid-connected inverter structure is required.

Hereinafter, an inverter switching control apparatus and its control method to be proposed by the present invention will be described in detail with reference to the drawings.

3 is a block diagram of an inverter switching control device that can be implemented according to the present invention. 3, the switching control apparatus 100 according to the present invention includes a forward directional compensator 10, a proportional integral controller 20, a limiter 40, 42, 44 and 46, a DQ inverse converter 50, (52) and the like. However, the components shown in Fig. 3 are not essential, so that the changeover control apparatus 100 having more or fewer components than those shown in Fig. 3 may be implemented.

An actual electric signal and a target electric signal are input to the input terminal of the grid-connected inverter (100). The input terminal of the grid-connected inverter 100 may be modeled as the input switch section 2, 4, 6.

The first input switch 2 is connected to the D-axis component I d, real of the measured current, and the second input switch 4 is connected to the D axis of the target current component is connected to the (I d, ref), the third input switch 6 may be modeled as being connected to the Q-axis component of the measured current (I q, real). The first input switch 2 is connected to the D axis component (V d, real ) of the actual voltage and the second input switch 4 is connected to the D axis component (V d, real ) of the target voltage in the single operation mode. V d, ref ), and the third input switch 6 is connected to the Q-axis component (V q, real ) of the actual voltage.

The deflection compensator 10 serves to set a target electric signal of the grid-connected inverter 100. Here, the target electric signal may be the D-axis component (V d, ref ) of the target voltage to be received at the system side, that is, the D-axis target voltage at the system side. The output V q, FF of the forward compensator 10 is input to the first limiter 40 and the output of V d, FF is input to the second limiter 42.

The proportional integral controller (PI controller) 20 corrects the error (sensing error, electrical constant change) of the deflector 10 value.

The proportional-plus-integral controller 20 multiplies the input signal by a specific gain value (P gain) to perform proportional control. The proportional-integral controller 20 multiplies the specific gain value I gain and performs an integral operation The result of performing the integral control can be outputted. Here, the gain values (P, I gain) may be preset and adjusted for control performance. Various proportional integral controllers 20 known in the art to which the present invention belongs may be applied as needed.

In the present invention, the proportional-plus-integral controller 20 comprises an error-proportional-integral controller 22 and an inverse proportional-integral controller 24, as shown in FIG.

The error-proportional-integral controller 22 receives the D-axis component of the actual electrical signal and the D-axis component of the target electrical signal and performs proportional control and integral control. The signal subtraction unit 30 is connected to the error proportional integral controller 22. The signal subtraction unit 30 subtracts the difference between the D axis component of the actual electric signal inputted to the error partial proportional integral controller 22 and the target electric signal And generates a difference signal of the D-axis component.

The inverse proportional integral controller 24 receives the D axis component of the actual electric signal and the D axis component of the target electric signal, and performs proportional control and integral control. An inverter 32 is connected to the inverse proportional integral controller 24 and the inverter 32 inverts the Q axis component of the actual electric signal input to the inverse proportional integral controller 24. [

The limiters 40, 42, 44, and 46 receive the output signals of the deflection compensator 10 and the proportional integral controller 20, and limit the magnitude of the signal to a preset predetermined range.

Specifically, the first limiter 40 limits the magnitude of the Q-axis component (V q, FF ) of the signal output from the deflector 10 to a preset predetermined range, and the second limiter 42 limits the magnitude of the Q- Axis component (V d, FF ) of the signal output from the compensator 10 to a preset predetermined range. The third limiter 44 limits the magnitude of the signal output from the error-proportional-plus-integral controller 22 to a preset predetermined range, and the fourth limiter 46 limits the magnitude of the signal output from the inverse proportional- To a predetermined range set in advance.

The signal outputted from the second limiter 42 and the signal outputted from the third limiter 44 are summed by the first signal summing unit 34 and the inverter side D axis target voltages V d, . The signal output from the first limiter 40 and the signal output from the fourth limiter 46 are summed by the second signal summing unit 36 and the inverter Q-axis target voltages V q, ref, inv ) Is generated.

DQ inverse converter 50 receives the inverter-side D-axis target voltage generated by the first signal summation unit 34 and the inverter-side D-axis target voltage generated by the second signal summation unit 36, and performs inverse DQ conversion .

The PWM generator 52 receives the inversely converted signal from the DQ inverse transformer 50 and generates a PWM signal for generating an AC signal. Here, the PWM generator 52 can generate a PWM signal (on-off signal) for switching operation of the AC signal generating circuit by using the DQ inverted three-phase signal. For example, the PWM generator 52 may compare the input three-phase signal with a signal having a reference waveform such as a sawtooth wave or a triangle wave to generate a PWM signal for determining on / off of the switch. The grid-connected inverter 100 can generate an alternating current signal by operating the switch circuit using the PWM signal generated by the PWM generator 52. In order to generate an AC signal by operating the switching circuit using the PWM signal, various well-known switching circuits for generating AC signals can be used.

4A to 4C show a control locus for explaining the setting of the control area according to the present invention.

4A corresponds to the control trajectory in the grid linking mode. At this time, V pole, inverter = X L x i G + V G , and current control is performed. Where X L is the reactance between the inverter and the grid, i G is the grid current, and V G is the grid voltage.

The output voltage of the inductor must have a phase difference of 90 degrees from the system voltage in order to control the current which is in phase with the grid voltage. Therefore, the output voltage of the inverter should be located on the red arrow according to the current command value.

4B corresponds to the control trajectory in the single operation mode. At this time, V pole, inverter = X L x i G + R LOAD x i G , and voltage control is performed.

In order to control the output voltage, the slope of the output voltage of the inverter and the output voltage of the load side is determined by the ratio of X L and R LOAD , and the output voltage of the inverter should be located in the red arrow according to the voltage command value.

FIG. 4c shows a condition in which a transient problem may not occur when a systematic accident occurs even when the transfer algorithm does not exist.

The present invention can set the control area as shown in FIG. 5 based on FIGS. 4A to 4C, and FIGS. 5A and 5B schematically show control areas that can be applied to the present invention.

5A shows an embodiment for explaining the principle that the output voltage is diverted in various operation situations in which a system fault occurs in the grid connection mode and is switched to a single operation.

5A, the control trajectory is displayed as 62, and the states at A, B, C, and D are shown in Table 1 below. In the case of operating in the single operation mode, the control trajectory is displayed as 64, and the states at A ', B, C', and D 'are as shown in Table 2 below.

inverter Load system A Supply 10 kW Consumption of 7 kW 3 kW supply B 7 kW supply Consumption of 7 kW - C 4 kW supply Consumption of 7 kW 3 kW supply D 10 kW supply Consumption of 7 kW 17 kW supply

Output phase voltage Peak Phase A ' 444 V peak (overvoltage) normal B 311 V peak (normal) normal C ' 177 V peak (undervoltage) normal D ' 444 V peak (overvoltage) reversal

Referring to FIG. 5A and Tables 1 and 2, except for the case where the load power and the inverter power are the same, an overvoltage or a low voltage phenomenon occurs in a grid accident situation. In a section where the inverter receives energy from the system, And is inverted.

The present invention limits the control trajectory set by the limiters of the deflection compensator 10 and the proportional integral controller 20 to select the boundary of the control area 60 and adjusts the control trajectory of the entire grid- Only the area required for actual control among the control trajectory is taken. That is, the inverter 100 of the present invention satisfies the control of the power range (in the example, -10 kW to +10 kW) to be covered in the grid connection mode, and at the same time, The boundary of the control region 60 is selected so as to be operable only at 380 Vac ± standard%).

Referring to FIG. 5B, according to the switching control method of the present invention, the system 100 is controlled at the boundary of the control area 60 in a situation where a systematic accident occurs and the inverter 100 can not recognize the accident. Then, when the system fault is recognized, the voltage control is passed. At this time, since the copper wire moving to the optimum operating point (point B) for control is very short, a transient problem hardly occurs.

Figure 6 shows an embodiment of a control area set in accordance with Figure 5a. The shaded area 60a in FIG. 6 is a range of the output value of the deflector 10 and the area 60b indicated by a circle existing around a certain point in the shaded area 60a is a proportional integral controller 20). The overall control area 60 appears with the proportional integral controller area 60b added to the deflector compensator area 60a. This region is wider than the area required for current control in the grid-connected mode, and can be prevented from selecting the output voltage narrower than the allowable grid voltage range in single operation mode.

The output voltage control region of the deflector compensator region 60a is a mathematical region obtained by taking into account the variation of the system voltage and the variation of L. [ In this regard, in the grid connection mode, it is derived by the following equations (1) and (2).

Figure 112016026302015-pat00001

Figure 112016026302015-pat00002

In the single operation mode, it is derived by the following equation.

Figure 112016026302015-pat00003

Figure 112016026302015-pat00004

Here, V q, FF = 0, and? FF = 0. Here, the impedance? R can be the impedance of the filter at the system frequency (the total impedance value of the filter formed at the system frequency).

The proportional integral controller region 60b represents the output voltage control region of the proportional integral controller 20. [ This control region serves to correct an error (sensing error, change in electrical constant, etc.) of the value of the deflector 10. At this time, the inverter module operates as a current controller by receiving a current command in a grid connection situation, and operates as a voltage controller by receiving a voltage command in a single operation state. Here, the third limiter 44 and the fourth limiter 46 can be set such that the upper control region is smaller than the operation limit range of the inverter during stand-alone operation.

On the other hand, Fig. 7 shows a simulation result waveform for the ablation control apparatus of the present invention.

Referring to FIG. 7, it can be confirmed that stable voltage and current are normally supplied to the load even if a system fault occurs in the normal grid connection mode M1 (M2, M3).

In particular, it can be seen that the inverter 100 is switched without a transient problem even in the situation M2 in which the inverter 100 is not aware of the system fault. Inverter 100 recognizes the system fault and is converted into the voltage control mode in the current control mode It can be confirmed that the situation (M3) is transferred without a transient problem. It can be confirmed that the phase shifts to the normal control mode (M1) without any transient problem after the phase synchronization in the power-down situation (M4).

The present invention can also be embodied as computer-readable codes on a computer-readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission via the Internet) . The computer readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers of the technical field to which the present invention belongs.

In addition, the above-described method and apparatus using the same may be applied to a case where the configuration and method of the embodiments described above are not limitedly applied. As shown in FIG.

Claims (13)

1. An apparatus for controlling switching between a grid connection mode and a single operation mode in a grid connection inverter operated in a grid connection mode connected to a grid or in a single operation mode in which connection with the grid is disconnected,
A forward compensator for setting a target electric signal to be output from the grid-connected inverter; And
And a proportional integral controller for compensating an actual electrical signal and an error of the target electrical signal,
Wherein the proportional integral controller comprises:
An inverse proportional integral controller for receiving a Q-axis component of the actual electric signal, performing proportional control and integral control, and outputting the result; And
A D-axis component of the actual electric signal and a D-axis component of the target electric signal, performing proportional control and integral control on the D-axis component of the input actual electric signal and the D- Further comprising an error-proportional integral controller for outputting a result value,
The switching control device sets a predetermined control region, limits the output of the grid-connected inverter to the set control region,
Wherein the control region is set to be narrower than a voltage range that is wider than a power range required for the system in the grid connection mode and does not cause divergence in the single operation mode. delete delete The method according to claim 1,
Wherein the inverse proportional integral controller further comprises a reverser for inverting the Q-axis component of the input actual electric signal,
Wherein the error proportional plus integral controller further comprises a signal subtracter for generating a difference signal between a D axis component of the input actual electric signal and a D axis component of the target electric signal. The method according to claim 1,
A first limiter for limiting a magnitude of a Q-axis component (V q, FF ) of a signal output from the beam former to a predetermined range; And
Further comprising a second limiter for limiting the magnitude of the D-axis component (V d, FF ) of the signal output from the deflection compensator to a preset predetermined range. 6. The method of claim 5,
A third limiter for limiting the magnitude of the signal output from the error-proportional-plus-integral controller to a predetermined range; And
Further comprising a fourth limiter for limiting the magnitude of the signal output from the inverse proportional integral controller to a predetermined range. The method according to claim 6,
A first signal summation unit for summing the signal output from the second limiter and the signal output from the third limiter to generate an inverter-side D-axis target voltage (V d, ref, inv ); And
Further comprising a second signal summation unit for generating an inverter Q-axis target voltage ( Vq, ref, inv ) by summing the signal output from the first limiter and the signal output from the fourth limiter controller. 8. The method of claim 7,
A DQ inverse transformer for receiving and DQ-inverting the inverter-side D-axis target voltage generated by the first signal summation unit and the inverter-side Q-axis target voltage generated by the second signal summation unit; And
Further comprising a PWM generator for receiving a signal reverse-converted by the DQ inverse transformer and generating a PWM signal for generating an AC signal. The method according to claim 1,
Wherein the control region comprises:
And a proportional integral controller region determined by the proportional integral controller is set using the forward compensator region determined by the forward compensator and the proportional integral controller region determined by the proportional integral controller. 10. The method of claim 9,
Wherein the control area is defined by a combination of a first area and a second area, wherein the first area is configured by the deflector compensator area, and the second area is defined by the proportional integral controller area including all parts in the first area Wherein the transfer control device is an area generated by overlapping. A method of controlling switching between a grid-connected mode and a single-operation mode in a grid-connected inverter operated in a grid-connected mode connected to a grid or in a single-operated mode in which connection with the grid is disconnected,
A first step of the transfer control device setting a predetermined control area; And
And a second step in which an output of the grid-connected inverter is limited within the set control area,
In the first step,
Setting a target electric signal to be output from the grid-connected inverter; And
Wherein the proportional integral controller further comprises compensating an error of the actual electrical signal and the target electrical signal,
The proportional plus integral controller includes an inverse proportional integral controller for receiving a Q-axis component of the actual electric signal, performing proportional control and integral control, and outputting a result of the proportional control and integral control, And an error component proportional integral controller for performing proportional control and integral control on the D axis component of the input actual electric signal and the D axis component of the target electric signal to output the resultant value ,
Wherein the control region set in the first step is narrower than a voltage range that is wider than a power range required for the system in the grid-connected mode and does not diverge in the single-operation mode. delete delete
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Citations (1)

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Publication number Priority date Publication date Assignee Title
KR101375812B1 (en) * 2012-09-24 2014-03-20 한국전력공사 Apparatus and method for controlling distributed resource in micro-grid

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101375812B1 (en) * 2012-09-24 2014-03-20 한국전력공사 Apparatus and method for controlling distributed resource in micro-grid

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