JP2003088141A - Power converter for grid connection - Google Patents

Abstract

(57) [Problem] To provide a power interconnection device for system interconnection that does not have a risk of deteriorating control accuracy even when the interconnected power system has imbalance. SOLUTION: An unbalance correction circuit 6 is provided in a system interconnection power conversion device 1 in which an AC side of a power conversion unit by a switching main circuit 36 operates in connection with a distribution system 34. The phase data θd by the phase control system 2 is corrected in accordance with the unbalanced state of the three-phase voltages, and the voltage commands Eu, Ev, Ew by the voltage command system 5 are corrected. [Effect] It is possible to reduce the imbalance of the power supply current and the power supply current distortion caused by the voltage imbalance of the power supply, and obtain effects such as not stopping the overcurrent of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter operating in cooperation with an AC power system, and more particularly to a sine wave converter capable of controlling an AC current flowing from the power system in a sine wave shape. Called a power converter.

[0002]

2. Description of the Related Art In recent years, direct current power generated by solar cells, fuel cells, etc. is converted into alternating current and is connected to a power system to flow to a distribution system, or AC power is taken from the distribution system and converted to direct current. Then, by charging the storage battery,
Power conversion devices for grid interconnection, which enable effective use of electric power, are attracting attention.

By the way, in such a power converter,
It is necessary that the current flowing in the power system can be controlled to an accurate sinusoidal current.Therefore, the phase of the AC power supply is detected, phase data synchronized with the AC power supply is created, and the main circuit of the power converter ( It is designed to control the switching main circuit).

Therefore, the phase command system for creating this phase data will be described with reference to FIG.
In the phase command system 2 shown in, the equations (1) to (5) in FIG.
8 shows a phase command system 2 of a method of creating phase data by using the α-β conversion shown in FIG. 8 and the dq conversion calculation shown in (Expression 6) to (Expression 10) in FIG. First, set the power supply frequency of 50Hz or 60Hz to the reference frequency ω0_S.
Then, the phase data θ1 is created by integrating the addition result of this and the frequency correction amount Δ_ω.

Then, (+) π / 2 is added to the phase data θ1.
Is added to generate the phase data θd, whereby the SIN / COS table 11A is searched and the data sin θd and cos θd are derived. And
These data sin θd and cos θd are α-β together with the power supply voltage data VR_DT, VS_DT, and VT_DT.
The d-axis feedback voltage Vd_F is calculated by being supplied to the conversion / dq conversion block unit 8 where the α-β calculation and the dq calculation according to (Equation 1) to (Equation 10) are used.

Therefore, this d-axis feedback voltage Vd
The magnitude of _F changes depending on the phase difference between the phase data θ1 and the reference phase θR of the actual power supply voltage, and indicates sine data according to the phase difference. For example, when the phase difference is 0, Vd_F
Is 0. When a phase difference occurs, θ1 becomes θR
On the other hand, when the phase is delayed, it is (+), and when it is advanced, it is (-). For example, if the delay is 90 degrees, the positive value is the same as the peak value of the voltage.

Therefore, this d-axis feedback voltage Vd
_F is compared with the reference value Vd (= 0) so that it is always 0, and the deviation is compensated by the proportional-integrator 17 to obtain the frequency correction amount Δ_ω, which is, as described above,
A feedback loop is formed by adding it to the reference frequency ω0_S, and as a result, the phase data θ1 is as shown in FIG.
It starts from the 180 degree point of θR and converges on the phase data that synchronizes at the next 180 degree point. At this time, the synchronization state of the phase θd is also as shown in FIG.

Then, the control circuit in the prior art of the power conversion device for grid interconnection provided with this phase command system 2 will be described with reference to FIG. 10. Here, first, the effective power current command system 3 will be described. By comparing the voltage VP_DATA of the DC power source and its command value VP_S and adjusting the deviation between them with the proportional / integrator 24 and the output limiter 25, the effective power current command Iq_s is output. Supply to ACR system 4.

In the DC ACR system 4, the AC output current data IR_DT and IT_DT output from the first-order delay soft filter 15 and the SIN / COS table 11 are provided.
The data sin θd and cos θd output from C are also input.

At this time, from the viewpoint of convenience in actual operation, the correction data generating unit 13 is provided and SIN / COS
In the phase data θd used for searching the table 11C,
A minute phase based on the current control system phase correction data THTA_IF is added so that a filter delay at the time of voltage detection and current detection of the power supply and a delay of the output current of the power conversion device by the main circuit filter may be added as necessary. It can be corrected.

Therefore, the DC ACR system 4 is operated by α-β conversion /
The data sin θd and cos θd output from the SIN / COS table C by the dq conversion block unit 9,
Based on the AC output current data IR_DT and IT_DT supplied from the first-order lag soft filter 15, this is also the α-β conversion calculation and dq similarly to the above-described phase data creation.
A conversion operation is performed, and the active component feedback current Iq_F and the reactive component feedback current Id_F, which are the AC output currents of this converter device.
Is converted to a DC amount of.

The active power feedback current Iq_F is the active power current command Iq input to the DC ACR system 4.
_s, on the other hand, the reactive feedback current Id_F is compared with the reference value Id_s (= 0), and these deviations are proportional to each other.
After the adjustment by the integrator 21 and the output limiter 22, the current control system non-interference compensation data 23 is added or subtracted, so that the DC ACR system 4 performs a current control process called a so-called DC ACR system, and the effective voltage command Vq_s.
And the reactive voltage command Vd_s are output.

Here, the current control system non-interference compensation data 23
Is the data corresponding to the inductance value (ωL) by the power-source cooperative AC reactor 37. The active voltage command Vq_s and the reactive voltage command Vd_s, which are the output results of this current control, are the reverse values in the voltage command system 5. It is input to the dq conversion two-phase / 3-phase conversion unit 10.

The effective voltage command Vq_s and the reactive voltage command Vd_s are stored in the SIN / COS table 11B.
Data sin θd and cos θd are supplied to the inverse dq conversion two-phase / three-phase conversion unit 10, where:
On the one hand, the inverse dq conversion processing is performed by the operations of the expressions (Equation 11) to (Equation 13) shown in FIG. 11, and on the other hand, the expression shown in FIG.
As a result of the two-phase / three-phase conversion processing by the calculation of (Equation 14) to (Equation 19), output voltage commands Vu, V of the power conversion device
v and Vw are obtained.

Therefore, the output voltage commands Vu, Vv, V
w is a power converter such as a converter (not shown)
To the PWM data corresponding to the carrier frequency.
As a result of creating the data and driving the main switching elements of the power conversion device by switching, a power conversion device that operates in cooperation with the power system is obtained.

Here, the automatic modulation rate calculation circuit 16 is configured to, when the converter is started, generate the data VR__ according to the magnitude of the DC voltage.
It generates SO and automatically modulates the voltage command.

[0017]

In the above-mentioned conventional technique, it cannot be said that the existence of the unbalanced voltage is taken into consideration, and there is a problem in that the control accuracy is lowered.

That is, the prior art has the advantages of high response and good followability to frequency fluctuations of the power system and less risk of malfunction due to noise, but on the other hand, when there is an imbalance in the voltage of the power system. , The value of the d-axis feedback voltage Vd_F does not converge to 0, becomes a value with a bias, and has a ripple component of the second harmonic.

Therefore, in the prior art, the phase data θd
Accuracy is deteriorated, which affects the dq conversion of the current control and the inverse dq conversion of the voltage command creation, which causes the problem of deterioration of the output voltage accuracy of the converter device.

Further, in the prior art, when the direct current ACR method is adopted for the current control as described above, the unbalanced state of each phase current due to the power source voltage imbalance cannot be grasped as a change for each phase. It is difficult to compensate the current for each phase, the output current imbalance and the distortion rate are increased, and problems such as overcurrent stoppage are also caused.

Further, in the prior art, the inverse dq conversion theory and the two-phase / three-phase conversion theory adopted for preparing the output voltage command can obtain accuracy only under the three-phase equilibrium condition. Therefore, also in this point, a large unbalance and distortion occur in the current due to the unbalanced state of the power supply voltage, and a problem such as overcurrent occurs.

Here, FIG. 13 shows an example of a current waveform that is unbalanced due to an unbalanced state in the prior art. As described above, in the conventional technique, when there is an unbalanced power supply voltage. Causes deterioration of accuracy in the phase data θd, and it is difficult to compensate the current for each phase due to the control principle (using the direct current ACR method as the current control method), so that the above-mentioned various problems occur.

An object of the present invention is to provide a system interconnection power conversion device that does not have a risk of deteriorating control accuracy even if there is an imbalance in the interconnected power system.

[0024]

The above object is to provide a power converter installed between an AC power supply and a DC power supply via an AC reactor for power supply coordination, and to create phase data synchronized with the phase of the AC power supply. In the power conversion device for grid interconnection, which controls the power conversion unit to perform mutual conversion between AC power and DC power, means for creating a reference amplitude value representing an unbalanced portion of the AC power supply, and the reference amplitude. Means for creating an amplitude ratio of each phase with respect to a value, and correcting the phase data by the amplitude ratio of each phase.

At this time, a means for creating an active power component current command from the voltage of the DC power supply and a command value of the DC power supply to the power conversion unit, and an AC output current of the power conversion unit as an active component feedback current and an invalid component. Means for converting the effective power component current command into the effective component feedback current and the reactive component feedback current to zero so that the reactive component feedback current converges to zero. A means for inversely converting and calculating the three-phase voltage command of the power conversion unit from the divided voltage command and the reactive voltage command, and means for multiplying and correcting the amplitude ratio by the three-phase voltage command are provided. However, the above-mentioned object can be achieved.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The power conversion device for grid interconnection according to the present invention will be described in detail below with reference to the embodiments shown in the drawings.

First, referring to FIG. 1, the present invention is applied to a PWM type power converter to operate an inverter, and a solar cell 44 is used.
Power distribution system 3 by converting the DC power generated by a into AC power
In one embodiment in which the power flow is set to 4, the whole power converter including the control system is represented by 1, and the main circuit portion of the power converter is represented by the switching main circuit 39. .

In the power converter 1 shown in FIG. 1, the DC power generated by the solar cell 44a is input to the smoothing capacitor 40 and converted into AC by the switching main circuit 39 which constitutes the main circuit section of the power converter. After being
Power cooperation AC reactor 37, high frequency ripple removal filter 36, insulation transformer 35, and relay (contact) 46
The power is supplied to the power distribution system 34 via the.

At this time, the control of the power converter 1 is performed by the PT
(Insulation transformer for power supply voltage detection) 14, DC voltage detector 41, and CT (insulation transformer for current detection) 38.
The isolation transformer 35 is not essential and may be omitted.

At this time, as shown in FIG. 2, a storage battery 44b is provided instead of the solar cell 44a, and the storage battery 44b is provided.
In addition to the inverter operation for flowing electric power from the power distribution system 34 to the power distribution system 34, the power distribution system 34 may also operate as a converter for charging the storage battery 44b from the power distribution system 34. Therefore, FIG. 2 is a second embodiment of the present invention. The embodiment of FIG. 1 corresponds to the first embodiment.

Next, FIG. 3 shows a third embodiment of the present invention. In FIG.
In an embodiment in which the induction motor 45 is driven by combining c, in this case, the smoothing capacitor 40 is
At the start of operation, the initial charging current suppressing resistor 47, the insulation transformer 3
5, the high frequency ripple removal filter 36, the power-source cooperative AC reactor 37, the current detector 38, and the free wheel diode connected in parallel to each switching element of the switching main circuit 39 to be charged first.

After the voltage is established by this charging, the relay 46 is turned on and the switching control of the switching main circuit 39 is started, whereby DC power is supplied to the inverter device 44c. The electric motor 45 can be operated by the inverter device 44c, and the switching main circuit 3 is operated during the regenerative operation.
9 operates as an inverter.

Also at this time, the control of the power converter 1 is controlled by P
Although it is performed based on T14, the DC voltage detector 41, and the information detected by CT38, the insulating transformer 35 is not essential here either and may be omitted.

Next, the operation of these embodiments will be described. Here, in any of the first to third embodiments described above, the control method is basically the same, and at this time, the polarity of the active current command depends on the direction of power, that is, whether it is the inverter operation or the converter operation. Since the difference is positive or negative, the control of each embodiment will be commonly described below.

Here, in the case of the above-mentioned embodiment, the control system has the same configuration, and is basically divided into the following four system blocks.

The first block is composed of a phase command system 2 which creates phase data θ1 and θd synchronized with the power supply from the input of the power supply voltage, and the second block is a DC voltage. The effective power current command system 3 compares the command values and proportionally / integrally adjusts the deviation for output.

The third block uses the AC output current of the converter device as the effective feedback current Iq_F and the reactive feedback current Iq.
d_F is converted into a DC amount, and these are supplied from the second block as the effective power current command Iq_s and the reference command I.
DC ACR system 4 that controls the current by comparing with d_s (= 0)
It is composed of.

Further, the fourth block has an effective voltage command Vq_S and a reactive voltage command Vd_S output from the third block.
The DC amount of S is converted into a three-phase voltage command, and the voltage command Eu,
It is composed of a voltage command system 5 for outputting Ev and Ew.

Here, first, the conversion processing in each of the conversion units 8 (FIG. 6), 9 and 10 in these blocks is the same as in the prior art.

Therefore, the difference between these embodiments and the prior art is that they are different from the prior art.
As is clear from the figure, the point that the unbalance correction circuit 6 is added before the phase command system 2 forming the first block, and the voltage command system 5 forming the fourth block. In addition, the unbalance correction compensating circuit 7 is added.

Further, again, from the viewpoint of convenience in actual operation, the correction data generating unit 12 is provided, and the SIN / C
Phase data θd used for searching the OS table 11B
Further, the voltage control system phase correction data THTA_PWM can be added, whereby the phase can be finely adjusted, and the filter delay in the power supply voltage detection and the control cycle delay of the PWM data can be corrected as necessary.

By the way, in any of the embodiments shown in FIGS. 1 to 3, the carrier wave generating circuit 42 and the PWM pulse signal generating circuit 43 are provided, and the voltage commands Eu, Ev, Ew output from the voltage command system 5 are supplied. PWM pulse signal generation circuit 4
3, the PWM signal is generated by modulating the sawtooth wave signal supplied from the carrier wave generation circuit 42. Then, the switching main circuit 39 is switching-controlled by this PWM signal, and the required operation is performed as an inverter or a converter.

Next, the unbalance correction circuit 6 and the unbalance correction compensation circuit 7 in these embodiments will be described with reference to FIGS.
Will be explained. Here, FIG. 4 is a diagram showing details of the unbalance correction circuit 6 and the unbalance correction compensation circuit 7, and FIG.
FIG. 6 is a diagram showing details of the unbalance correction processing circuit 26.

4 and 5, the power supply voltage of each phase of the power system is first lowered by PT14, and then digitally converted by A / D converter 31 to become data VR_AD, VS_AD, VT_AD. The data is captured by the A / D conversion data capture circuit 32. And after this,
The first order delay is made by the soft filter 33, processed into respective data VR_DATA, VS_DATA, VT_DATA, and supplied to the unbalance correction circuit 6.

These data input to the unbalance correction circuit 6 are directly supplied to the unbalance correction processing circuit 26 on the one hand, but are also supplied to the maximum value selection circuit 27 on the other hand. Then, the maximum value selection circuit 27 detects the absolute peak value data S_VOLU, S_VOLV, S_VOLW for each phase for each control cycle, and then the peak value detection circuit 28 detects the amplitude data HC_VOLU, HC_VOLV, HC for each phase.
_VOLW is detected as a peak value for each cycle of the power supply, and then is also supplied to the unbalance correction processing circuit 26.

In the unbalance correction processing circuit 26, the amplitude data HC_VOL of each phase, as shown in detail in FIG.
U, HC_VOLV, HC_VOLW are added as they are,
It is ⅓ and processed into the amplitude data V_AV serving as a reference. In parallel with this, the operator 29A is multiplied for each phase. Then, this multiplication result is divided by the amplitude data V_AV, and data KR, K representing the amplitude ratio of each phase is obtained.
Process into S and KT.

Therefore, the unbalance correction processing circuit 2 at this time
The relational expression of the arithmetic processing by 6 is the following (Equation 20), (Equation 2)
It becomes as shown in 1) and (Equation 22).

VR_DT = VR_DATA / KR (Equation 20) VS_DT = VS_DATA / KS (Equation 21) VT_DT = VT_DATA / KT (Equation 22) These amplitude ratios KR, KS, On the other hand, KT is output from the unbalance correction processing circuit 26 as it is, and is supplied to the unbalance correction compensation circuit 7 in the voltage command system 5 as the amplitude ratio data 30 (FIG. 4) of each phase.

In the unbalance correction processing circuit 26,
The data VR_DATA, VS_DATA, VT_DATA input directly from the first-order lag soft filter 33 is multiplied by the operator 29B, and then the value for each phase is divided by the amplitude ratios KR, KS, KT of each phase to obtain the corrected data VR.
_DT, VS_DT, VT_DT are processed.

Therefore, these correction data are sent to the phase command system 2
To the power supply voltage data VR_DT, VS_DT, VT_D input to the phase command system 2 even if there is an imbalance in the power supply voltage.
T is always balanced corrected data, that is, corrected data VR_DT, VS_DT, VT_DT. As a result, for example, even if the power supply voltage has an imbalance of 10%,
There is no risk of synchronization deviation or blurring of the phase data, and the accuracy of the phase data θ1 and θd can be increased.

Returning to FIG. 4, in the unbalance correction compensating circuit 7 in the voltage command system 5, the effective voltage command Vq_S and the reactive voltage command Vd_S, which are the output results of the DC ACR command system 4, are subjected to inverse dq conversion. The voltage commands Vu, Vv, Vw obtained by processing in the 2-phase / 3-phase converter 10 are input.

Therefore, in the unbalance correction compensation circuit 7,
First, the amplitude ratios KR, KS, and KT of these phases are multiplied by the voltage commands Vu, Vv, and Vw, then the operator 29C is divided, and then the product is inverted by multiplying by -1 to obtain the voltage commands Eu,
Process into Ev and Ew.

As a result, if there is an imbalance in the power supply voltage, the voltage command E for each phase is determined according to the amplitude ratio of the voltage due to this imbalance.
u, Ev, and Ew will also be in an unbalanced state.

Here, the reason why -1 is multiplied and inverted is that the phase data θ1 is handled with a difference of 180 degrees with respect to the reference phase θR.

Therefore, the unbalance correction compensation circuit 7 at this time
The basic relational expression of the arithmetic processing by is the following (Equation 23), (Equation 2)
4), as shown in (Equation 25).

Eu = Vu * KR (Equation 23) Ev = Vv * KS (Equation 24) Ew = Vw * KT (Equation 25) Then, the voltage command for each phase Eu, Ev, Ew PW
If it is supplied to the M pulse signal generation circuit 43, the difference voltage appearing in the impedance between the power supply voltage and the output of the power converter can be made equal between the phases, and as a result, there is an imbalance in the power supply voltage. Also, the current is prevented from becoming unbalanced, and the distortion rate can be improved.

Therefore, according to the above embodiment, even if there is an imbalance of 10% in the power supply voltage, for example, there is no possibility that the phase data will be out of synchronization or shake, so that the accuracy of the phase data can be improved. Moreover, even if there is an imbalance in the power supply voltage, the current is prevented from becoming unbalanced, so the distortion rate can be improved, and as a result, control accuracy is improved even if there is an imbalance in the interconnected power system. It is possible to easily obtain a power conversion device for grid interconnection that is not likely to deteriorate.

[0058]

According to the present invention, it is possible to reduce the imbalance of the power supply current caused by the voltage imbalance of the commercial power supply, the power supply current distortion, and the effect of not stopping the device for the overcurrent. .

Further, according to the present invention, the direct current component current due to the imbalance can be suppressed, so that the effect that there is no possibility of causing the magnetic bias phenomenon in the power transformer can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a power conversion device for grid interconnection according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of a power conversion device for grid interconnection according to the present invention.

FIG. 3 is a third power conversion device for grid interconnection according to the present invention.
It is a block diagram showing an embodiment of.

FIG. 4 is a block diagram showing an example of a control system including an unbalance correction circuit according to an embodiment of the present invention.

FIG. 5 is a block diagram showing details of an unbalance correction circuit according to the embodiment of the present invention.

FIG. 6 is a block diagram showing an example of a phase command system in the power conversion device.

FIG. 7 is an explanatory diagram of an α-β conversion formula in the power conversion device.

FIG. 8 is an explanatory diagram of a dq conversion formula in the power conversion device.

FIG. 9 is a waveform diagram showing an example of a phase data synchronization state in the power conversion device.

FIG. 10 is a block diagram showing an example of a control circuit in a power conversion device for grid interconnection according to a conventional technique.

FIG. 11 is an explanatory diagram of an inverse dq conversion formula in the power conversion device.

FIG. 12 is an explanatory diagram of a two-phase / three-phase conversion formula in the power conversion device.

FIG. 13 is a waveform diagram showing an example of the output current when the power supply voltage is unbalanced in the conventional power conversion device.

[Explanation of symbols]

1 power converter (whole control block) 2 phase command system 3 active power current command system 4 DC ACR system 5 voltage command system 6 unbalance correction circuit 7 unbalance correction compensation circuit 8 α-β conversion / dq Conversion block unit 9 α-β conversion / dq conversion block unit 10 Inverse dq conversion Two-phase / 3-phase conversion unit 11A, 11B, 11C SIN / COS table 12 Voltage command system Phase correction data generation unit 13 Current control system Phase correction data generator 14 PT (insulation transformer for power supply voltage detection) 15 Converter output current detector 1st order delay soft filter 16 Automatic modulation rate calculation circuit at converter startup 17, 21, 24 Proportional / integrator 18, 22, 25 Proportional -Integrator, output limiter 19 Reference frequency 20 Frequency shift adjustment data 23 Current control system non-interference compensation data (power inductor AC inductor 37 inductor Value ωL) 26 unbalance correction processing circuit 27 maximum value selection circuit 28 peak value detection circuits 29A, 29B, 29C operator (operator representing decimal number 100: D'100) 30 amplitude ratio of each phase of power supply voltage waveform 31 A / D converter 32 A / D conversion data acquisition circuit 33 Power supply voltage detection unit Primary delay soft filter 34 Distribution system (distribution system power supply) 35 Isolation transformer 36 High frequency ripple removal filter 37 Power supply cooperative AC reactor 38 CT (current) (Insulation transformer for detection: current transformer) 39 Switching main circuit 40 Smoothing capacitor 41 DC voltage detection circuit 42 Carrier wave generation circuit 43 PWM pulse signal generation circuit 44a Solar cell 44b Storage battery device 44c Inverter device 45 Motor 46 Relay 47 Initial charging current suppression Resistance VR, VS, VT Power supply voltage VU, VV, VW of power distribution system Output of power converter Voltage IU_F U-phase current of power converter IW_F W-phase current of power converter IR_DATA U-phase current data of power converter IT_DATA W-phase current data of power converter VP_DATA DC voltage data of power converter VP_DC voltage command PWM PWM Pulse signal θd, θ1 Command data Vd-F d-axis voltage feedback Vq-F q-axis voltage feedback VR_S Reference voltage command Vu Before correction U-phase voltage command Vv Before correction V-phase voltage command Vw Before correction W-phase voltage command Eu After correction U Phase voltage command Ev Corrected V phase voltage command Ew Corrected W phase voltage command THTA_PWM Voltage command system phase compensation data THTA_IF DC ACR (current control system) phase compensation data Iq_S Effective power current command Id_S Reactive effective power current command Iq_F Effective power feedback Current Id_F Reactive power feedback current Vq_S q axis valid Pressure command Vd_S d-axis reactive voltage directive

Continued front page    (72) Inventor Satoshi Ibori             Chiba Prefecture Narashino City Higashi Narashino 7-1-1             Hitachi Drive Systems Co., Ltd. (72) Inventor Hiroyuki Kazusa             Chiba Prefecture Narashino City Higashi Narashino 7-1-1             Within Hitachi KEE Systems Inc. F-term (reference) 5G066 GC02                 5H007 AA07 AA17 BB07 CA01 CB05                       CC07 CC32 DA03 DA06 DB01                       DC05 EA15

Claims (2)

[Claims] 1. A power converter provided between an AC power supply and a DC power supply via an AC reactor for power supply cooperation, and creates phase data synchronized with the phase of the AC power supply to control the power converter. However, in the power conversion device for grid interconnection that performs mutual conversion between AC power and DC power, means for creating a reference amplitude value representing an unbalanced portion of the AC power supply, and an amplitude ratio of each phase with respect to the reference amplitude value. A power conversion device for grid interconnection, which is provided with a means for creating and corrects the phase data according to an amplitude ratio of each phase. 2. The invention according to claim 1, wherein a means for creating an effective power component current command from the voltage of the DC power supply and a command value of the DC power supply to the power converter, and an AC output of the power converter. Means for converting a current into an active feedback current and a reactive feedback current; and current control means for compensating the active power current command so that the active power feedback current converges to the active feedback current and the reactive feedback current converges to zero. A means for inversely converting and calculating a three-phase voltage command of the power conversion unit based on an effective component voltage command and a reactive component voltage command by the current control means; and means for multiplying and correcting the amplitude ratio by the three-phase voltage command. And a power conversion device for grid interconnection.