JP2014121133A - System interlocked inverter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system interlocked inverter device in which, when one system voltage is sound, a power generation performance of a distributed power source can be sufficiently presented.SOLUTION: A system interlocked inverter device 10 connecting a distributed power source 2 to a single-phase three-wire type commercial system power source 3 comprises: a single-phase three-wire type inverter circuit 40 for converting DC power generated by the distributed power source 2 into AC power; a current command generator 6 for generating a current command value iaccording to a power generation capability of the distributed power source 2; and an inter-phase effective power regulator 90 which generates an U-phase effective current command value iand a W-phase effective current command value ifor controlling U-phase output and W-phase output of the inverter circuit 40 on the basis of results of comparing an U-phase system voltage vand a W-phase system voltage vof the commercial system power source 3 with a regulation start threshold value (first threshold value), respectively, and the current command value igenerated by the current command generator 6.

Description

  The present invention relates to a grid-connected inverter device that connects a distributed power source to a commercial grid power source.

  A grid-connected inverter device that converts DC voltage output from a small-scale distributed power source such as a photovoltaic power generation system or a fuel cell power generation system into a sinusoidal AC voltage and performs grid-connected operation with the distribution system is known. (For example, refer to Patent Document 1).

  When a distributed power source is connected to a distribution system by a grid-connected inverter device, the voltage of each part of the distribution line may increase due to the reverse power flow from the distributed power source to the distribution system, and may deviate from the appropriate voltage of the distribution system. is there. In this case, the installer of the distributed power source needs to take measures to maintain the receiving point voltage within an appropriate voltage. For this reason, it is common to provide a voltage rise suppression function (automatic voltage adjustment function) as standard in a grid-connected inverter device that connects a distributed power source and a distribution system.

  One of the voltage rise suppression functions is an output control function. The output control function is a function of maintaining the power receiving point voltage within an appropriate range by suppressing the generated power and reducing the reverse flow rate. By installing the output control function, it is possible to effectively maintain the power receiving point voltage within an appropriate range.

As shown in FIG. 10, a conventional grid-connected inverter device 1 is connected between a distributed power source 2 such as a solar cell that generates DC power and a commercial power source 3 composed of a single-phase three-wire distribution line. Is done. A conventional grid-connected inverter device 1 includes a single-phase two-wire inverter circuit 4 that converts DC power generated by a distributed power source 2 into AC power by turning on and off a power element (not shown), and an output side of the inverter circuit 4. is connected, a filter circuit 5 that outputs to a commercial system power supply 3 to smooth the output current waveform of the inverter circuit 4, a current command generator 6 for generating a current command value i _L ^*, based on the current command value i _L ^* A conversion controller 7 that controls the inverter circuit 4 and an output suppression control determiner 8 that instructs the current command generator 6 to suppress the output.

The current command generator 6 is a current command according to the power generation capability of the distributed power source 2 by MPPT control (Maximum Power Point Tracking) based on the output voltage or output current I of the distributed power source 2. and the generated current command generator 61 to generate the value i _L ^*, suppressing suppression current command generating a current command value i _L ^* generated by the generating current command generator 61 based on an instruction from the output suppression control determiner 8 And a switch 63 for switching the output of the generated current command generator 61 and the suppressed current command generator 62 based on an instruction from the output suppression control determiner 8.
The conversion controller 7 generates and outputs a v _iuw control signal for causing the inverter circuit 4 to output an output voltage v _iuw for making the current command value i _L ^* and the output current i _L coincide with each other.
Output suppression control determination unit 8 monitors the system voltage _{v suo} and system voltage _{v sow,} when it reaches the suppression start threshold even either one of the system voltage _{v suo} and the system voltage _{v sow,} suppression current command switch 63 While switching to the generator 62 side, it instructs the suppression current command generator 62 to suppress the current command value i _L ^* .

FIG. 11A shows a current command value suppression operation when the system voltage v _suo reaches the suppression start threshold. At time t ₁₀ begins to rise system voltage v _suo, upon reaching suppression start threshold at time t _11, the output suppression control determiner 8, switches the switch 63 to inhibit the current command generator 62 side, suppression current command generation The controller 62 is instructed to suppress the current command value i _L ^* . As a result, the current command value i _L ^* is suppressed from the power generation possible current value according to the power generation capability of the distributed power source 2 so that the system voltage v _suo does not exceed the suppression start threshold.
FIG. 11B shows a current command value suppression operation when the system voltage v _sow reaches the suppression start threshold. When the system voltage v _sow starts to increase at time t ₂₀ and reaches the suppression start threshold at time t ₂₁ , the output suppression control determination unit 8 switches the switch 63 to the suppression current command generator 62 side and generates the suppression current command. The controller 62 is instructed to suppress the current command value i _L ^* . Thus, the current command value i _L ^* is suppressed from the power generation possible current value according to the power generation capability of the distributed power source 2 so that the system voltage v _sow does not exceed the suppression start threshold.
FIG. 11C illustrates a current command value suppression operation when the system voltage v _suo and the system voltage v _sow reach the suppression start threshold. Time _{t 30} in starting to rise system voltage _{v suo} and system voltage _{v sow,} and reaches the suppression start threshold at time _{t 31,} the output suppression control determiner 8, switches the switch 63 to inhibit the current command generator 62 side Instruct the suppression current command generator 62 to suppress the current command value i _L ^* . Thus, the current command value i _L ^* is suppressed from the power generation possible current value according to the power generation capability of the distributed power source 2 so that the system voltage v _suo and the system voltage v _sow do not exceed the suppression start threshold. Become.

JP 2003-9399 A

However, in the related art, when either one of the system voltage v _suo and the system voltage v _sow reaches the suppression start threshold, the current command value i _L ^* is suppressed and the output current i _L is reduced. That is, although either the system voltage v _suo or the system voltage v _sow is healthy, the output control function may operate, and the power generation performance of the distributed power source 2 may not be fully exhibited. There was a problem. In particular, when the reverse power flow increases due to the widespread use of the distributed power supply 2 and the centralized interconnection, the system voltage becomes close to the upper voltage limit and the output control function is easy to operate. There are many cases where this is not fully demonstrated.

  The object of the present invention is to solve the above-mentioned problems of the prior art in view of the above-mentioned problems, and when one system voltage is healthy, the grid interconnection that can sufficiently exhibit the power generation performance of the distributed power supply It is to provide an inverter device.

The grid-connected inverter device of the present invention is a grid-connected inverter device that connects a distributed power source to a single-phase three-wire commercial grid power source, and converts the DC power generated by the distributed power source into AC power. A single-phase three-wire inverter circuit, a current command generator for generating a current command value according to the power generation capability of the distributed power source, a system voltage of U phase and W phase of the commercial power source, and an adjustment start threshold value; The U-phase and W-phase effective current command values for controlling the U-phase output and the W-phase output of the inverter circuit, respectively, based on the respective comparison results and the current command value generated by the current command generator Are provided, respectively.
Further, in the grid-connected inverter device according to the present invention, the interphase active power regulator is configured such that when only one of the U-phase system voltage and the W-phase system voltage is equal to or greater than the adjustment start threshold. An effective current phase adjustment operation may be performed in which the effective current command value of a phase whose voltage is equal to or higher than the adjustment start threshold is decreased and the decrease is increased by the effective current command value of another phase.
Furthermore, in the grid-connected inverter device of the present invention, the current command generator is such that either the U-phase system voltage or the W-phase system voltage is greater than or equal to the suppression start threshold value higher than the adjustment start threshold value. In this case, a current command value suppression operation for suppressing a current command value according to the power generation capability of the distributed power source may be executed.

  According to the present invention, when one system voltage is healthy, an increase in the other system voltage can be suppressed without executing the output limiting function, so that the power generation performance of the distributed power source is sufficiently improved. There is an effect that it can be exhibited.

It is a circuit block diagram which shows the circuit structure of 1st Embodiment of the grid connection inverter apparatus which concerns on this invention. It is a circuit block diagram which shows the circuit structure of the inverter circuit shown in FIG. It is explanatory drawing explaining the flag management in the interphase active power regulator shown in FIG. It is a flowchart for demonstrating adjustment operation between active current phases in 1st Embodiment of the grid connection inverter apparatus which concerns on this invention. It is explanatory drawing explaining the flag management in the output suppression control determination device shown in FIG. It is a wave form diagram for demonstrating adjustment operation between active current phases in 1st Embodiment of the grid connection inverter apparatus which concerns on this invention. It is a wave form diagram for demonstrating the electric current command value suppression operation | movement in 1st Embodiment of the grid connection inverter apparatus which concerns on this invention. It is a circuit block diagram which shows the circuit structure of 2nd Embodiment of the grid connection inverter apparatus which concerns on this invention. It is a circuit block diagram which shows the circuit structure of the converter circuit shown in FIG. It is a circuit block diagram which shows the circuit structure of the conventional grid connection inverter apparatus. It is a wave form diagram for demonstrating the electric current command value suppression operation | movement in the conventional grid connection inverter apparatus.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
(First embodiment)
Referring to FIG. 1, a grid-connected inverter device 10 according to the first embodiment includes a distributed power source 2 such as a solar cell that generates DC power, and a commercial power source 3 including a single-phase three-wire distribution line. Connected between. The grid-connected inverter device 10 is connected to a single-phase three-wire inverter circuit 40 that converts DC power generated by the distributed power source 2 into AC power by turning on and off a power element (not shown), and an output side of the inverter circuit 40. , a filter circuit 50 to be output to the commercial system power supply 3 to smooth the output current waveform of the inverter circuit 40, a current command generator 6 for generating a current command value i L *, on the basis of the current command value i L * U phase and W-phase of each phase of the active current command value i Lu *, the phase active power regulator 90 for generating the i Lw *, and controls the inverter circuit 40 based on the active current command value i Lu *, i Lw * A conversion controller 70 and an output suppression control determination unit 80 that instructs the current command generator 6 to suppress output are provided.

  For example, as shown in FIG. 2, the single-phase three-wire inverter circuit 40 includes capacitors C1 and C2 and switch elements Q1 to Q4 that are power elements. The filter circuit 50 includes reactors L1 and L2 and capacitors C3 and C4.

  A capacitor C1 and a capacitor C2 are connected in series between a positive bus 41 and a negative bus 42 connected to the distributed power source 2. Further, between the positive bus 41 and the negative bus 42, the switch element Q1 and the switch element Q2 are connected as the first arm 43, and the switch element Q3 and the switch element Q4 are connected as the second arm 44. Has been. The midpoint of the first arm 43, that is, the connection point between the switch element Q1 and the switch element Q2 is a U-phase output, and is connected to the U-phase voltage output terminal U of the commercial power supply 3 via the reactor L1 of the filter circuit 50. Has been. The middle point of the second arm 44, that is, the connection point between the switch element Q3 and the switch element Q4 is a W-phase output, and is connected to the W-phase voltage output terminal W of the commercial power supply 3 through the reactor L2 of the filter circuit 50. Has been. Furthermore, the connection point between the capacitor C1 and the capacitor C2 is connected to the neutral line O of the commercial power supply 3. Further, a capacitor C3 is connected between the U-phase voltage output terminal U and the neutral wire O, and a capacitor C4 is connected between the neutral wire O and the W-phase voltage output terminal W.

The current command generator 6 is a current command according to the power generation capability of the distributed power source 2 by MPPT control (Maximum Power Point Tracking) based on the output voltage or output current I of the distributed power source 2. and the generated current command generator 61 to generate the value i _L ^*, suppressing suppression current command generating a current command value i _L ^* generated by the generating current command generator 61 based on an instruction from the output suppression control determiner 80 And a switch 63 for switching the output of the generated current command generator 61 and the suppressed current command generator 62 based on an instruction from the output suppression control determiner 80.

Phase active power regulator 90 monitors the system voltage _{v suo} and system voltage _{v sow,} a comparison result between the system voltage _{v suo} and system voltage _{v sow} the adjustment start threshold (first threshold), the current command generator Based on the current command value i _L ^* output from 6, a U-phase effective current command value i _Lu ^* and a W-phase active current command value i _Lw ^* are generated.

The conversion controller 70 generates a v _iuo control signal for making the effective current command value i _Lu ^* and the output current i _Lu coincide with each other, and makes the effective current command value i _Lw ^* and the output current i _Lw coincide with each other. A v _iow control signal is generated, and the generated v _iou control signal and v _iow control signal are output to the inverter circuit 40.

Output suppression control determination unit 80, when monitoring the system voltage _{v suo} and system voltage _{v sow,} reaches the system voltage _{v suo} and the system voltage _v either one even suppression start threshold of _sow (a second threshold), The switch 63 is switched to the suppression current command generator 62 side, and the suppression current command generator 62 is instructed to suppress the current command value i _L ^* . The suppression start threshold (second threshold) is set to a value higher than the adjustment start threshold (first threshold) used in the interphase active power adjuster 90.

Next, the active current phase adjustment operation in the interphase active power regulator 90 will be described with reference to FIGS. 3 and 4.
The interphase active power adjuster 90 manages the comparison result between the system voltage v _suo and the system voltage v _sow and the adjustment start threshold (first threshold) using the adjustment start flags “Flg-u” and “Flg-w”. doing. As shown in FIG. 3, "Flg-u" is "0" if the system voltage _{v suo} is less than the adjusted start threshold (first threshold), the system voltage _{v suo} adjustment start threshold (first Is set to “1”. Further, "Flg-w" is "0" if it is less than the system voltage _{v sow} adjustment start threshold (first threshold), the system voltage _{v sow} adjustment start threshold (first threshold) or more Then, it is set to “1”.

Referring to FIG. 4, interphase active power adjuster 90 first determines first-order lag response gain command value Kp ^* . The interphase active power adjuster 90 determines whether or not the current command value i _L ^* output from the current command generator 6 is within a predetermined range set in advance. Specifically, it is determined whether or not the current command value i _L ^* output from the current command generator 6 is less than or equal to the lower limit (step A1) and whether or not it is greater than or equal to the upper limit (step A2). . If the answer is Yes in step A1 or step A2, that is, if the current command value i _L ^* is not within the predetermined range set in advance, the interphase active power adjuster 90 generates the first-order lag response gain command value Kp. ^* Is determined to be “0” (step A3).

In the case of No in Step A1 and Step A2, that is, when the current command value i _L ^* is within a predetermined range set in advance, the interphase active power adjuster 90 performs “Flg-u” and “Flg− It is determined whether or not both “w” and “w” are set to “1” (step A4). In the case of Yes in Step A4, that is, both the system voltage v _suo and the system voltage v _sow are equal to or higher than the settling threshold (first threshold), and both “Flg-u” and “Flg-w” are “1”. If it is set, the interphase active power adjuster 90 determines the first-order lag response gain command value Kp ^* to “0” (step A3).

In the case of No in step A4, that is, when both “Flg-u” and “Flg-w” are not set to “1”, the interphase active power adjuster 90 indicates that “Flg-u” is “ It is determined whether or not “1” is set (step A5). In the case of Yes in step A5, that is, when only the system voltage v _suo is equal to or higher than the adjustment start threshold (first threshold) and only “Flg-u” is set to “1”, the interphase active power regulator 90 determines the first-order lag response gain command value Kp ^* to “−1.0” (step A6).

In the case of No in step A5, that is, when “Flg-u” is not set to “1”, the interphase active power adjuster 90 determines whether “Flg-w” is set to “1”. Is determined (step A7). In the case of Yes in step A7, that is, when only the system voltage v _sow is not less than the adjustment start threshold (first threshold) and only “Flg-w” is set to “1”, the interphase active power regulator In 90, the first-order lag response gain command value Kp ^* is determined to be “1.0” (step A8). In the case of No in step A7, that is, both the system voltage v _suo and the system voltage v _sow are less than the settling threshold (first threshold), and both “Flg-u” and “Flg-w” are “0”. If it is, the interphase active power adjuster 90 determines the primary delay response gain command value Kp ^* to “0” (step A9).

In the operations of Steps A1 to A9, the first-order lag response gain command value Kp ^* is determined to be “0”, “1.0”, or “−1.0”. Next, the interphase active power adjuster 90 calculates a first-order lag response gain Kp {Kp = 1 / (1 + sTc) * Kp ^* } based on the first-order lag response gain command value Kp ^* (step A10). The above equation is a general first-order lag response equation in the complex frequency region, and Tc means a self-constant.

Next, the interphase active power adjuster 90 is based on the first-order lag response gain Kp calculated in Step A10 and the current command value i _L ^* output from the current command generator 6, and the active current command value i _Lu ^{*. _{{i Lu * = i L *}} * (1 + Kp)} as well as calculating the (step A11), and calculates the active current command value ^{_{i Lw * {i Lw * =}} i L * * (1-Kp)} ( step A12 ), The effective current phase adjustment operation is terminated.

Next, the current command value suppression operation in the output suppression control determiner 80 will be described with reference to FIG.
The output suppression control determination unit 80 performs flag management of the comparison result between the system voltage v _suo and the system voltage v _sow and the suppression start threshold (second threshold) using a suppression start flag “Flg-sup”. As shown in FIG. 5, “Flg-sup” is set to “1” when both or one of the system voltage v _suo and the system voltage v _sow is equal to or higher than the suppression start threshold (second threshold). The When “Flg-sup” is set to “1”, the output suppression control determination unit 80 switches the switch 63 to the suppression current command generator 62 side, and also sends a current command value i to the suppression current command generator 62. Instructs suppression of _L ^* .

FIG. _6A shows the adjustment operation between active current phases when the system voltage v _suo reaches the adjustment start threshold (first threshold).
When neither the system voltage v _suo nor the system voltage v _sow has reached the adjustment start threshold (first threshold), both “Flg-u” and “Flg-w” are “0”. It becomes. Accordingly, the interphase active power adjuster 90 determines the first-order lag response gain command value Kp ^* to “0” in step A9 shown in FIG. Thus, in step A11, A12, active current command value _{i Lu} ^* and the active current command value _{i Lw} ^*, a current command value _i ^{L *} output from the current command generator 6 together.

At time _{t 40} begins to rise system voltage _{v suo,} upon reaching adjustment start threshold at time _{t 41,} only the "Flg-u" becomes "1". Therefore, the interphase active power adjuster 90 determines the primary delay response gain command value Kp ^* to “−1.0” in step A6 shown in FIG. 4, and the active current command value _iLu ^* is decreased in step A11. In step A12, the active current command value i _Lw ^* is increased. Thus, without suppressing the current command value i _L ^*, it is possible to suppress an increase in beyond the adjustment start threshold of the system voltage v _suo, it is possible to prevent the deterioration of power generation performance. Incidentally, the decrease of the active current command value i _Lu ^*, and the active current command value i _Lw ^* is increase, with the same value, the current command value i _L ^* output from the current command generator 6 at step A10 A value obtained by multiplying the calculated first-order lag response gain Kp. Therefore, always equal to the active current command value _{i Lu} ^* and the active current command value _{i Lw} ^* current command value 1/2 of the sum is outputted from the current command generator 6 and _i ^{L *.}

FIG. 6B shows the adjustment operation between effective current phases when the system voltage v _sow reaches the adjustment start threshold (first threshold).
When the system voltage v _sow starts to increase at time t ₅₀ and reaches the adjustment start threshold value at time t ₅₁ , only “Flg-w” becomes “1”. Therefore, the interphase active power regulator 90 determines the primary delay response gain command value Kp ^* to “1.0” in step A8 shown in FIG. 4, and the active current command value i _Lu ^* is increased in step A11. In step A12, the active current command value i _Lw ^* is decreased. Thereby, it is possible to suppress the increase of the system voltage v _sow beyond the adjustment start threshold without suppressing the current command value i _L ^*, and it is possible to prevent the deterioration of the power generation performance. Incidentally, active current command value i _Lu ^* and increase in, the active current command value i _Lw ^* is decrement, the same value, the current command value i _L ^* output from the current command generator 6 at step A10 A value obtained by multiplying the calculated first-order lag response gain Kp. Therefore, always equal to the active current command value _{i Lu} ^* and the active current command value _{i Lw} ^* current command value 1/2 of the sum is outputted from the current command generator 6 and _i ^{L *.}

FIG. 7A shows the current command value suppression operation when the system voltage v _suo reaches the adjustment start threshold (first threshold) and then further reaches the suppression start threshold (second threshold). ing.
System voltage _{v suo} at time _{t 42} begins further increased from the adjustment start threshold reaches the suppression start threshold at time _{t 43,} "Flg-sup" becomes "1". Accordingly, the output suppression control determination unit 80 switches the switch 63 to the suppression current command generator 62 side, and instructs the suppression current command generator 62 to suppress the current command value i _L ^* . As a result, the current command value i _L ^* is suppressed from the power generation possible current value according to the power generation capability of the distributed power source 2 so that the system voltage v _suo does not exceed the suppression start threshold, and the current command value i _L ^* With the decrease, the effective current command value _iLu ^* and the effective current command value _iLw ^* are also decreased. In addition, the current command value suppression operation by the output suppression control determination unit 80 and the active current phase adjustment operation by the interphase active power adjuster 90 operate independently. Therefore, in the example shown in FIG. 7A, the current command value i _L ^* is suppressed, and the effective current command value i _Lu ^* and the effective current command value i _Lw ^* are also adjusted. Also in this case, always equal to the active current command value i _Lu ^* and the active current command value i _Lw ^* current command value 1/2 of the sum is outputted from the current command generator 6 and i _L ^*.

FIG. 7B shows the current command value suppression operation when the system voltage v _sow reaches the suppression start threshold (second threshold) after reaching the adjustment start threshold (first threshold). ing.
System voltage _{v sow} at time _{t 52} begins further increased from the adjustment start threshold reaches the suppression start threshold at time _{t 53,} "Flg-sup" becomes "1". Accordingly, the output suppression control determination unit 80 switches the switch 63 to the suppression current command generator 62 side, and instructs the suppression current command generator 62 to suppress the current command value i _L ^* . Thereby, the current command value i _L ^* is suppressed from the power generation possible current value according to the power generation capability of the distributed power source 2 so that the system voltage v _sow does not exceed the suppression start threshold, and the current command value i _L ^* With the decrease, the effective current command value _iLu ^* and the effective current command value _iLw ^* are also decreased. In addition, the current command value suppression operation by the output suppression control determination unit 80 and the active current phase adjustment operation by the interphase active power adjuster 90 operate independently. Therefore, in the example shown in FIG. 7B, the current command value i _L ^* is suppressed, and the effective current command value i _Lu ^* and the effective current command value i _Lw ^* are also adjusted. Also in this case, always equal to the active current command value i _Lu ^* and the active current command value i _Lw ^* current command value 1/2 of the sum is outputted from the current command generator 6 and i _L ^*.

(Second Embodiment)
Referring to FIG. 8, the grid interconnection inverter device 11 of the second embodiment performs DC / DC conversion between the inverter circuit 40 and the distributed power source 2 in addition to the configuration of the first embodiment. A converter circuit 100 is connected. As a result, the output from the current command generator 6 is used as a current command value i _dc ^* for controlling the input current of the converter circuit 100, and the conversion controller 71 is used by the conversion controller 70 of the first embodiment. In addition to the function, a v _idc control signal for matching the current command value i _dc ^* and the input current i _dc is generated, and the generated v _idc control signal is output to the converter circuit 100. For example, as shown in FIG. 9, the converter circuit 100 includes a boost chopper circuit including a reactor L3, a switch element Q5 that is a power element, and a diode D1.

Further, the current command value i _L ^* to the inverter circuit 40 is generated by the converter / inverter power adjustment controller 110 so that the input power of the converter circuit 100 and the output power of the inverter circuit 40 are equal. Other configurations and operations are the same as those in the first embodiment.

As described above, according to the present embodiment, the grid-connected inverter device 10 that connects the distributed power supply 2 to the single-phase three-wire commercial power supply 3, and the direct current generated by the distributed power supply 2 is used. A single-phase three-wire inverter circuit 40 that converts electric power into AC power, a current command generator 6 that generates a current command value i _L ^* according to the power generation capability of the distributed power source 2, and the U of the commercial power source 3 Based on the comparison results between the phase system voltage v _suo and the W phase system voltage v _sow and the adjustment start threshold (first threshold) and the current command value i _L ^* generated by the current command generator 6 And an interphase active power regulator 90 for generating a U-phase active current command value _iLu ^* and a W-phase active current command value _iLw ^* for controlling the U-phase output and the W-phase output of the inverter circuit 40, respectively. I have.

Furthermore, according to the present embodiment, the interphase active power adjuster 90 is configured such that when only the U-phase system voltage v _suo is equal to or greater than the adjustment start threshold (first threshold), the U-phase active current command value i _{When Lu} ^* is decreased and the decrease is increased by the W-phase active current command value i _Lw ^* , and only the W-phase system voltage v _sow is equal to or higher than the adjustment start threshold (first threshold), W An effective current phase adjustment operation is executed to decrease the effective current command value i _Lw ^* of the phase and increase the decrease by the effective current command value i _Lu ^* of the U phase.

Further, according to the present embodiment, the current command generator 6 starts suppression, in which either the U-phase system voltage v _{suo or the} W-phase system voltage v _sow is higher than the adjustment start threshold (first threshold). When it is equal to or greater than the threshold value (second threshold value), a current command value suppression operation for suppressing the current command value i _L ^* according to the power generation capability of the distributed power source 2 is executed.

With this configuration, in the present embodiment, only the U-phase system voltage v _suo is equal to or higher than the adjustment start threshold (first threshold) and the W-phase system voltage v _sow is healthy. Since the current command value i _Lu ^* is reduced, it is possible to suppress an increase in the U-phase system voltage v _suo without executing the output limiting function. Even when only the W-phase system voltage v _sow is equal to or greater than the adjustment start threshold (first threshold) and the U-phase system voltage v _suo is healthy, the W-phase effective current command value i _Lw ^* is Therefore, the increase in the W-phase system voltage v _sow can be suppressed without executing the output limiting function. Accordingly, it is possible to prevent the U-phase system voltage v _suo and the W-phase system voltage v _sow from reaching the suppression start threshold (second threshold) at which the output limiting function is executed. The power generation performance can be fully exhibited.

  Although the present invention has been described above with specific embodiments, it is needless to say that the above embodiments are merely examples and can be implemented without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1, 10, 11 System interconnection inverter apparatus 2 Distributed type power supply 3 Commercial system power supply 4, 40 Inverter circuit 5, 50 Filter circuit 6 Current command generator 90 Interphase active power regulator 7, 70, 71 Conversion controller 8, 80 Output suppression control determiner C1 to C4 Capacitors Q1 to Q4 Switch elements L1 and L2 Reactor 41 Positive bus 42 Negative bus 43 First arm 44 Second arm 61 Generation current command generator 62 Suppression current command generator 100 Converter circuit 110 Converter / Inverter power adjustment controller

Claims (3)

A grid-connected inverter device for connecting a distributed power source to a single-phase three-wire commercial power source,
A single-phase three-wire inverter circuit that converts the DC power generated by the distributed power source into AC power;
A current command generator for generating a current command value according to the power generation capacity of the distributed power source;
The U-phase output of the inverter circuit based on the comparison result between the U-phase and W-phase system voltages of the commercial system power supply and the adjustment start threshold value and the current command value generated by the current command generator And an interphase active power regulator for generating U-phase and W-phase active current command values for controlling W-phase output and W-phase output, respectively.   The inter-phase active power regulator is configured to enable the effective phase of the phase having a system voltage equal to or higher than the adjustment start threshold when only one of the system voltage of the U phase and the system voltage of the W phase is equal to or higher than the adjustment start threshold. 2. The grid-connected inverter device according to claim 1, wherein an effective current phase adjustment operation is performed to decrease the current command value and increase the decrease by the effective current command value of another phase.   The current command generator follows the power generation capability of the distributed power source when either the U-phase system voltage or the W-phase system voltage is equal to or higher than a suppression start threshold value higher than the adjustment start threshold value. 3. The grid interconnection inverter device according to claim 1, wherein a current command value suppression operation for suppressing the current command value is executed.

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