JPH0625948B2 - Reactive power compensator - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a reactive power compensator, and an effective reactive power compensation system in a system for supplying power from an AC power supply system to an AC power bus to a load with a large fluctuation of reactive power. The present invention relates to a reactive power compensator for performing power compensation.

[Technical background of the invention and its problems]

In recent years, large-capacity arc furnace equipment has been connected to an AC power supply system and operated. As is well known, the arc furnace generates reactive power on the power supply side that fluctuates abruptly depending on the state of the melt in the furnace. This abruptly changing reactive power distorts the voltage waveform due to the interaction with the power supply system impedance and causes flicker of the lighting equipment, and also causes a reduction in the utilization rate of the power supply equipment. Therefore, when installing a large-capacity arc furnace, etc., a reactive power compensator is installed in parallel with the arc furnace to compensate for the rapidly fluctuating reactive power generated by the arc furnace and to fluctuate the reactive power of the AC power system. Is suppressed.

For such a reactive power compensator, see [Reference] Technical Report of The Institute of Electrical Engineers of Japan (Part II), April 1979, 76th edition.
Nos. P26 to P31, "Power Conversion Technology for Reactive Power / Harmonic Countermeasures", edited by the Special Committee for Permanent Rectifiers, the configuration is a power supply system as shown in FIG.

That is, in the figure, 10 is the load of the arc furnace,
Iron or the like is put into the furnace 12, and an electric current is caused to flow through the electrode 11 by electric discharge to heat and melt the iron inside. 9 is a transformer for the furnace.

Reference numeral 100 is a reactive power compensator, which is a reactor unit 300.
And a phase advancing capacitor section 200 that also serves as a harmonic filter. Reactor section 300 is reactor 302U-302W
And anti-parallel thyristors 301U to 301W connected in series with it
The load current detectors 81R, 81S, 81T, the voltage detecting transformer 70, and the control circuit 350 thereof detect the reactive power of the arc furnace 10, and the conduction angles of the thyristors 301U to 301W are detected according to the detected value. Adjusted and the reactor current is controlled. That is, in the reactive power compensator 100, the reactor is coupled with the action of the phase advance capacitor 200.
The electric current of 302U to 302W is controlled, and the amount of lead reactive power equal to the generated reactive power (delay) of the arc furnace 10 is applied to the lines 51R, 5R.
It is controlled to occur in 1S and 51T, and the reactive power disappears at the point of the three-phase bus 4 and only the active power of the load flows. Therefore, the voltage distortion of the bus bar 4 is reduced, and the utilization factor of the power supply equipment is improved. Reference numeral 3 is a system impedance existing in a three-phase AC power supply system, and 1 is a power supply source such as a three-phase AC power supply system or a transmission and distribution bus.

In the reactive power compensator (100) having the above configuration, the control circuit 3
According to 50, how accurately the reactive power generated by the load (10) is detected is the key to the device performance. An example of this reactive power detection circuit is shown in FIG.

That is, FIG. 9 is a circuit disclosed in FIG. 2 of Japanese Patent Laid-Open No. 59-139416. First, when a product q of a 90 ° delayed waveform e _{90 of a} bus voltage e and a load current i _L is created, q has a form in which a direct current component (reactive power component) and an alternating current component that oscillates at twice the fundamental frequency are included. This signal is passed through a low-pass filter, and the direct current component q _VAR (amount of reactive power)
Is detected, and the current of the reactor part 300 is controlled based on this.

Besides, various reactive power detection methods have been proposed, but the gist thereof can be reduced to the principle disclosed in Japanese Patent Laid-Open No. 59-139416.

The above is the description of the conventional reactive power compensator, but this device has the following drawbacks. That is, when the fluctuating power (including active power and reactive power) generated by an arc furnace is analyzed, the component of the DC amount that does not fluctuate (that is, the positive phase power due to the positive phase voltage and the positive phase current) ) And a fluctuating component (that is, the negative phase power caused by the positive phase voltage and the negative phase current), the conventional reactive power detection method clearly separates these positive phase power and negative phase power. There is no concept, therefore, the electric power is regarded only as a fluctuation component in which the positive-phase electric power and the negative-phase electric power are mixed together, and the reactor current is controlled based on the fluctuation. Therefore, what is to be compensated in the conventional reactive power compensator, that is, whether the positive-phase reactive power (component that does not fluctuate) is controlled or the negative-phase reactive power (component that fluctuates) is controlled. In principle, it was not possible to discriminate between, and it was impossible to develop into more advanced control.

In recent years, there has been a strong demand for improving the quality of power in the AC power system,
In order to meet this demand, there is a strong demand for more advanced control of reactive power compensators for flicker countermeasures in arc furnaces, etc., and reactive power compensators for AC power system stabilization measures, and this requirement is satisfied. Therefore, the emergence of a reactive power compensator equipped with a highly accurate power detection method (including active and reactive components) based on a new control concept is desired.

[Object of the Invention]

The present invention has been made in view of the above-mentioned problems of the prior art,
The purpose is to separate and detect the positive-phase component and the negative-phase component in the load current in a device that compensates the reactive power generated by the load of an arc furnace, etc. Another object of the present invention is to provide a reactive power compensator capable of performing highly accurate compensation control.

[Outline of Invention]

In order to achieve the above object, the present invention relates to a reactive power compensator for compensating reactive power generated by a load connected to an AC power system, and a two-phase current signal obtained by converting a detected load current into two phases, A unit two-phase voltage signal synchronized with the AC bus voltage to which the load is connected and a unit two-phase voltage signal having a frequency twice the frequency of the AC bus voltage are used, and the positive phase invalid in the load current is calculated through the calculation of these signals. The component and the anti-phase component are separately detected, a current command for the reactive power compensator is created based on this detection signal, and the reactive power compensator is controlled based on this current command value.

Example of Invention

The power supply system including the reactive power compensator of the present invention is the same as that of FIG. 8, and the description of the elements mentioned in the description of the conventional example is omitted here.

In FIG. 8, 81R, 81S, and 81T are current detectors, which detect the currents (i _RL , i _SL , i _TL ) of the arc furnace 10 and guide them to the control circuit 350. Reference numeral 70 denotes a voltage detector that detects the voltage (e _RS , e _ST , e _TR ) of the busbar to which the arc furnace 10 (including the furnace transformer 9) is connected and guides it to the control circuit 350.
Reference numeral 300 denotes a reactor portion, which is usually delta-connected, and the magnitude of the current is adjusted by adjusting the firing angle of the thyristors 301U to 301W. The reactor current usually has a distorted waveform including harmonics in addition to the fundamental wave.

Reference numeral 400 is an arithmetic circuit incorporating the present invention.
_RL , i _SL , i _TL and the voltage signals e _RS , e _ST , e _TR are input, various calculations are performed, and the current command I _U ^* of the direct current value for instructing the fundamental wave current that the reactor unit 300 should flow, I _V ^* , I
Output _W ^* .

Reference numeral 500 denotes an ignition controller, which is a current command value I _U ^* , I _V ^* , I
It operates by receiving _W ^* and controls the firing of thyristors 301U, 301V, 301W so that reactors 302U, 302V, 302W flow the current (fundamental wave component) indicated by I _U ^* , _IV ^* , I _W ^*. .

A combination of the arithmetic circuit 400 and the ignition controller 500 is called a control circuit 350, and the details of this circuit are shown in FIG.

Next, the main part of the present invention will be described with reference to FIGS.
In the present invention, the following description will be given by taking as an example the case where the reactor portion 300 of FIG. 8 is delta-connected. The same symbols in FIGS. 1 and 8 represent the same elements and the same signals.

In FIG. 1, reference numeral 402 denotes a line / phase converter, and the load current signals i _RL , i _SL , and i _TL detected as the line currents in FIG. 8 are calculated by the equation (1), and the phase current i _UL of the delta connection, i _VL , i
Convert to _WL (Conversion of formula (1) is performed by reactor part 3 in Fig. 8)
00 is a necessary conversion when the delta connection is used, and this conversion is not necessary when the star connection is used).

_{Reference numeral} 403 denotes a two-phase converter which converts the current signals i _UL , i _VL , i _WL into two-phase current signals i _1dL , i _1qL by the calculation of the equation (2).

405 inputs the AC bus voltage signals e _RS , e _ST, and e _TR shown in FIG. 8, and based on this, the phase lock loop circuit (PLL
A two-phase signal generator obtained by constructing a circuit), and as its output, the first phase is the R phase and the second phase is the S phase in FIG.
If the phase and the third phase are the T phase, the unit sine wave signal ▲ e ^* _1d1 ▼ synchronized with the line voltage e _RS of the first and second phases, and
The unit sine wave signal ▲ e ^* _1q1 ▼ delayed by 90 ° and its phase signal ▲ θ ^* _1d1 ▼ are output, and ▲ e ^* _1d1 ▼ and ▲ e ^* _1q1 ▼ are _expressed by
(3) (Note that when the reactor part 300 in FIG. 8 is star connected, ▲ e ^* _1d1 ▼, ▲ e ^* _1q1 ▼ are synchronized with the phase voltage of the first phase).

_{Reference numeral} 404 denotes an arithmetic unit, which outputs signals i _1dL , i _1q1 and ▲ e ^* _1d1.
Input ▼, ▲ e ^* _1q1 ▼, and use the formula (4) to input signals Q _1P and P _1P
Is calculated.

When the load currents i _RL , i _SL , and i _TL include a positive phase component / a negative phase component, Q _1P and P _1P become a pulsating flow that includes a direct current component and an alternating current component that oscillates at twice the frequency of the fundamental wave. .

Reference numeral 407 denotes a separator, which is composed of direct current detection filters 408 and 409 and adders 410 and 411, receives the signals Q _1P and P _1P, and outputs direct current detection filters 408 and 409.
Detects the DC components of Q _1P and P _1P and outputs them as signals Q _1PD and P _1PD . At the adders 410 and 411, the DC components, that is, Q _1PD and P _1PD, are output from the signals Q _1P and P _1P. It is removed and only the AC component is output as the signals Q _1PA and P _1PA . The DC amount signals Q _1PD and P _1PD obtained here represent the positive phase reactive current (Q _1PD ) and the positive phase active current (P _1PD ) included in the load currents i _RL , i _SL , and i _TL .

_{Reference numeral} 415A denotes a distributor, which receives signals Q _1PD , Q _1PA , P _1PA and a phase angle signal ▲ θ ^* _1d1 ▼ to perform an operation, and a current command value I for instructing a current flowing by the reactor unit 300 in FIG. _U ^* , _IV ^* , and _IW ^* are output. The details of the distributor 415A are shown in FIG.

Reference numeral 500 denotes an ignition controller, which is a current command value I _U ^* , I _V ^* , I _W ^*.
The thyristors 301U, 301V, 301W are ignited and controlled so that the reactor unit 300 causes the current (fundamental wave component) designated by I _U ^* , I _V ^* , I _W ^* to flow.

Next, the distributor 415A will be described with reference to FIG. Signals having the same symbols in FIGS. 1 and 2 are connected according to the symbols.
In FIG. 2, reference numeral 416A is a two-phase generator, which operates by receiving the phase angle signal ▲ θ ^* _1d1 ▼ and has a frequency of 2 of the AC bus voltage.
Two-phase voltage signal of formula (5) with double frequency ▲ e ^* _1d2 ▼, ▲
e ^* _1q2 ▼, ▲ e ^* _2d2 ▼, ▲ e ^* _2q2 ▼, ▲ e ^* _3d2 ▼, ▲ e
^* _{Generates 3q2} ▼.

Reference numeral 417A is an arithmetic unit, which outputs signals Q _1PA , P _1PA and ▲ e.
^{_{* 1d2 ▼, ▲ e * 1q2}} ▼ input expression (6) by a signal Q _1ND, P
Calculate _1ND . Similarly, the 418A and 419A are also arithmetic units, and the signals Q _1PA and P _1PA and ▲ e ^* _2d2 ▼ and ▲ e, respectively.
^* _2q2 ▼, Q _1PA , P _1PA and ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼ are input and the signals Q _2ND , P _2ND , and Q _3ND , P _3ND are calculated by equations (7) and (8). .

The signals P _1ND and Q _1ND thus obtained include the negative phase current included in the first phase current i _UL of the equation (1) as the in-phase component (P _1ND ) in the line voltage of the first and second phases and 90 ° phase difference component (Q _1ND )
The currents of the respective components when decomposed into are represented as follows. Here, P _{1ND is referred} to as a first-phase in-phase reverse-phase current signal, and Q _1ND is referred to as a first-phase 90 ° reverse-phase current signal. Similarly, P _2ND ,
Q _2ND is the negative phase current included in the second phase current i _{VL in} equation (1)
In-phase component current (P _2ND : second phase) when it is decomposed into the in-phase component and the 90 ° phase difference component in the line voltage of the third phase
Phase in-phase current) and 90 ° phase difference current components (Q _2ND : second phase 90 ° anti-phase current). Similarly, P _3ND and Q _3ND are components of the same phase in the line voltage of the third phase and the first phase and a component different in 90 ° phase from the reverse phase current included in the third phase current i _WL of the equation (1). 2 _shows the in-phase component current (P _3ND : third-phase in-phase reverse-phase current) and the 90 ° _-phase different current component (Q _3ND : third-phase 90-degree reverse-phase current). These signals P _1ND , Q _1ND , P _2ND , Q _2ND ,
P _3ND and Q _3ND are DC signals.

The signals Q _1PD , Q _1ND , P _1ND , Q _2ND and P thus obtained
_2ND , Q _3ND and P _3ND are input to the next distributor 440A.

Next, reference numeral 447 is a setting device, which is the reactor unit 30 shown in FIG.
0 outputs a reactive current setting signal Q _1MAX for instructing the maximum value of the reactive current (delay) that should be generated.

440A is a distributor, in which the positive phase reactive current signal Q _1PD detected from the load current of the arc furnace, the first phase,
Second-phase and third-phase 90 ° reverse-phase current signals Q _1ND , Q _2ND , Q _3ND
Input the in-phase and out-of-phase current signals P _1ND , P _2ND , P _3ND and the reactive current setting signal Q _1MAX , and formula based on these signals.
The calculation of (9) is performed, and the reactor unit 30 of FIG.
0 for the first phase reactor 302U to indicate the current to be generated by the first phase current command I _U ^* , and similarly for the reactor 302V second phase current command I _V ^* , and for the reactor 302W. To output a third-phase current command I _W ^* for Here, the following elements are included in the distributor 440A. That is, 441A, 442A, 443A are coefficient multipliers, Double and output. 444A, 445A and 446A are adders which add the outputs of the coefficient units 441A, 442A and 443A with the polarities shown. The outputs of the adders 444A, 445A, and 446A correspond to the calculation of the third term of Expression (9). 448A is an adder, which is used for setting signal Q _1MAX and signal Q
Calculate _1PD with the _indicated polarity. That is, the output of the adder 448A corresponds to the calculation of the first term of the equation (9). 449A, 450A, 451
A is an adder, and signals Q _1ND , Q _2ND , Q _3ND and adder 4
The output signal of 48A and the output signals of the adders 444A, 445A and 446A are added with the polarities shown.

The signals I _U ^* , I _V ^* , and I _W ^* obtained by the above calculation are DC amount signals, and this signal contains all the information about the positive-phase current and the information about the negative-phase current. Therefore,
When the reactor 300 shown in FIG. 8 is controlled based on these I _U ^* , I _V ^* , and I _W ^* so that the load current of the arc furnace or the like contains a large amount of the negative phase component in addition to the positive phase component. However, the current at point 4 in FIG. 8 can be freely balanced.

The above is a typical configuration of the present invention.

Next, the operation of the present invention will be described.

First, in FIG. 8, the electric current of the arc furnace is the signal i _RL ,
Although detected as i _SL and i _TL , this current is usually an unbalanced current including a positive phase component and a negative phase component. On the other hand, the signals e _RS , e _ST , e
_It is detected as _TR and introduced into the control circuit of the reactive power compensator 100. Next, in FIG. 1, the two-phase generator 405 receives the signals e _RS , e _ST , and e _TR, and outputs the two-phase signal ▲ based on the equation (3)
e ^* _1d1 ▼, ▲ e ^* _1q1 ▼ and its phase angle signal ▲ θ ^* _1d1 ▼ are output.

On the other hand, the signals i _RL , i _SL , and i _TL detected as the line currents are converted by the equation (1) in the line / phase converter 402,
As a result, the phase currents i _UL , i _VL , and i _WL of the delta connection (that is, for example, the reactor section 30 in the delta connection of FIG. 8).
If 0 is taken as an example, it is converted into a current flowing through the reactors 302U, 302V, 302W). This signal i _UL , i _VL , i
_{The WL} is converted by the equation (2) in the two-phase converter 403, and two-phase signals i _1dL and i _qL are obtained. Next, arithmetic unit 40
4 to obtain the signals Q _1P and P _1P , and pass them through the separator 407 to obtain the DC component signals Q _1PD and P _1PD.
And AC component signals Q _1PA and P _1PA . The signal Q _1PD thus obtained is the load current signals i _RL , i _SL , i
_It represents the positive-phase reactive current contained in _TL (or may be paraphrased as i _UL , i _VL , and i _{WL in} Expression (1)).

The signals Q _1PD , Q _1PA , Q _1NA and the phase angle signal ▲ θ ^* _1d1 ▼ are introduced to the next distributor 415A.

In the distributor 415A of FIG. 2, the two-phase generator 416A receives the phase angle signal ▲ θ ^* _1d1 ▼ and outputs the unit two-phase voltage signal of the formula (5) having a frequency twice that of the AC bus voltage. Occur. Further, in the arithmetic units 417A, 418A, and 419A, equations (6), (7),
The calculation of (8) is performed, and the in-phase reverse-phase current signals P _1ND , P _2ND , P _3ND of the first phase, the second phase, and the third phase, and the first phase, the second phase
The 90 ° negative phase current signals Q _1ND , Q _2ND and Q _{3ND of} the first and third phases are obtained.

The signal Q _1PD obtained as described above is the load current i _RL ,
i _SL , i _TL is a signal related only to the positive-phase component current, and further, if the positive-phase component current can be decomposed into an active current and a reactive current, it is only related to the reactive current. I.e., a signal related only to the positive-phase reactive current. In the calculation of various quantities related to the positive phase of the current, for example, the conversion of Q _1P or the like in Expression (4), the same quantity is calculated regardless of which phase the calculation is performed. Therefore, the calculation for the positive phase component may be performed for one phase.

Also, the signals P _1ND , Q _1ND and P _2ND , Q _2ND and P _3ND ,
Focusing on Q _3ND , these signals can be applied to i of load current equation (1).
_UL , i _VL , and i _WL (or i _RL , i _SL , and i _TL may be paraphrased) are signals related only to the negative-phase component current, and further, P _1ND and Q _1ND are currents. i _UL 's reverse phase component only, P _2ND , Q _2ND only i _VL 's reverse phase _component P _3ND , Q
_3ND is a signal related only to the reverse phase _component of the current i _WL . More specifically, taking P _1ND and Q _1ND as an example, P _1ND has the same phase as the line voltage in the reverse phase component of the current i _UL . It is a current component, and Q _1ND is a signal related only to the current component that is 90 ° out of phase with the voltage.

As described above, all the information of the load currents i _RL , i _SL , and i _TL are DC signals Q _1PD , P _1ND , P _2ND , P _3ND , Q _1ND , Q _2ND , Q.
It will be clear that they are separately detected in the form of _3ND .

The signal thus obtained is expressed in the distributor 440A shown in FIG.
Distributing current commands I _U ^* , I _V ^* , and I _W ^* are made along (9). Based on these current commands I _U ^* , I _V ^* , and I _W ^* , the current of the reactor part in FIG. 8 is calculated. When controlled, the anti-phase current is controlled so that the phase of the anti-phase component current of the current generated by the arc furnace and the phase of the anti-phase component current of the compensation current generated by the reactor unit 300 are exactly opposite to each other. Therefore, regarding the anti-phase component, these are combined at points 51R, 51S, 51T and cancel each other, so that the anti-phase current does not flow to the power source 1 and the current of the power source 1 is balanced. . Next, regarding the positive-phase reactive current, the output signal of the adder 448A of FIG. 2 acts, and as a result, the positive-phase reactive component (delay) of the current generated by the load and the reactor unit 3 of FIG.
00 is controlled so that the sum of the compensation current generated by 00 and the positive-phase reactive component (delay) is exactly equal to the reactive current setting signal Q _1MAX (delay) shown in FIG. The reactive current and the advance reactive current of the phase advancing capacitor 200 shown in FIG. 8 cancel each other out. As a result, the reactive current stops flowing to the AC power supply 1 shown in FIG. 8 and a load is generated in the AC power supply. Only the positive-phase active current will flow.

From the above description, when the reactive power compensating device of the present invention operates, even if the load of the arc furnace or the like generates an unbalanced current including a positive phase component and a negative phase component, the reactive current is compensated and the reverse current is compensated. Since the phase current is compensated, only the positive-phase active current flows through the AC power supply, and therefore the voltage fluctuation (that is, flicker).
It can be seen that the power consumption can be improved (that is, reactive power does not have to be handled) and the power consumption can be suppressed.

The above is a typical embodiment of the present invention.

Next, a second embodiment of the present invention will be described with reference to FIG. That is, FIG. 3 is a modification of the distributor 415A of FIG. 2 of the above-mentioned invention, and FIG. 3 is inserted and used in the distributor 415A of FIG. Therefore, this modified example has many parts that overlap with the invention described above, and the description of the overlapping parts will be omitted. The same symbols in FIGS. 3 and 1 are connected according to the symbols.

In FIG. 3, reference numeral 416A denotes a two-phase generator, which receives the phase angle signal ▲ θ ^* _1d1 ▼ like the invention of FIG. 2 and receives the unit two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ shown in the equation (5). e ^* _1q2 ▼, ▲ e ^* _2d2
▼, ▲ e ^* _2q2 ▼, ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼ are generated.

417B is a calculator, the signal Q _1PA, P _1PA and _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ signals by input (10) and Q
Calculate _1ND (90 ° reverse-phase current signal of the first phase). This Q
_1ND is the same as the signal Q _1ND obtained by the equation (6) described above. Reference numerals 418B and 419B are also arithmetic units, and the signals Q _1PA , P _1PA , ▲ e ^* _2d2 ▼, ▲ e ^* _2q2 ▼ and the signal Q, respectively.
_{Input 1PA} , P _1PA , ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼, and enter the formula (1
Signals Q _2ND , Q _3ND (second phase, third phase 90
Calculate the negative-phase current signal). Also here, Q _2ND and Q _3ND are the same as the signals Q _2ND and Q _3ND obtained by the above-mentioned equations (7) and (8).

^{_{Q 1ND = ▲ e * 1d2 ▼}} · Q 1PA + ▲ e * 1q2 ▼ · P 1PA ... (1
0) Q _2ND = ▲ e ^* _2d2 ▼ ・ Q _1PA + ▲ e ^* _2q2 ▼ ・ P _1PA … (1
1) Q _3ND = ▲ e ^* _3d2 ▼ ・ Q _1PA ＋ ▲ e ^* _3q2 ▼ ・ P _1PA … (1
2) 447 is a setter which outputs a reactive current setting signal Q _1MAX . 440B is a distributor, which is a positive-phase reactive current signal Q _1PD , a 90 ° negative-phase current signal Q of the first phase, the second phase, and the third phase.
_1ND , Q _2ND , Q _3ND and reactive current setting signal Q _1MAX are input, and the calculation of formula (13) is performed based on these signals, and the first
The current commands I _U ^* , I _V ^* , and I _W ^* of the phase, the second phase, and the third phase are output. Here, the coefficient units of 453B, 454B, and 455B also double the input signal and output it. Also, 448A, 449B, 450B, 451B
Is an adder that adds the signals shown in the drawing with the polarities shown.

The current commands I _U ^* , I _V ^* , and I _W ^* are exactly the same as the current command values obtained by the above-mentioned equation (9), and therefore I _U ^* ,
When the current of the reactor part 300 of FIG. 8 is controlled on the basis of I _V ^* and I _W ^* , the same compensation effect as that of the invention according to FIGS. 1 and 2 described above can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 417B, 418B, 419B in FIG. 3 can be simplified and the cost can be reduced as compared with the arithmetic units 417A, 418A, 419A of the invention shown in FIG.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a modification of the distributor 415A of FIG. 2 of the above invention, which is inserted into the distributor 415A of FIG. The same signal points in FIGS. 4 and 1 are connected according to the symbols.

In FIG. 4, 416A is a two-phase generator, which receives the phase angle signal ▲ θ ^* _1d1 ▼ like the invention of FIG. 2 and receives the unit two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ shown in the equation (5). e ^* _1q2 ▼, ▲ e ^* _2d2
▼, ▲ e ^* _2q2 ▼, ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼ are generated.
417C, 418C, 419C are arithmetic units, and the signals Q _1PA , P
_1PA and _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ and _{^{▲ e * 2d2 ▼, ▲ e}} *
_{Input 2q2} ▼ and ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼ and formula (14) (15)
According to (16), the signal P _1ND (first-phase in-phase reverse-phase current signal),
P _2ND (second-phase in-phase reverse-phase current signal) and P _3ND (third-phase in-phase reverse-phase current signal) are calculated. These obtained signals P
_1ND , P _2ND , and P _3ND are the same as P _1ND , P _2ND , and P _3ND obtained by the equations (6), (7), and (8) described above.

^{_{P 1ND = ▲ e * 1d2 ▼}} · P 1PA - ▲ e * 1q2 ▼ · Q 1PA ... (1
4) P _2ND = ▲ e ^* _2d2 ▼ ・ P _1PA − ▲ e ^* _2q2 ▼ ・ Q _1PA … (1
5) P _3ND = ▲ e ^* _3d2 ▼ ・ P _1PA − ▲ e ^* _3q2 ▼ ・ Q _1PA … (1
6) 447 is a setter which outputs the reactive current setting signal Q _1MAX . 440C is a distributor, which is a positive-phase reactive current signal Q _1PD , a first-phase, a second-phase, and a third-phase in-phase reverse-phase current signal P
_1ND , P _2ND , P _3ND and reactive current setting signal Q _1MAX are input, and the calculation of formula (17) is performed based on these signals, and the first
The current commands I _U ^* , I _V ^* , and I _W ^* of the phase, the second phase, and the third phase are output. Here, 441A, 442A, 443A are coefficient multipliers, Double and output. Further, 453B, 454B and 455B are also coefficient units, which double the input signal and output it. And 444A, 445A, 44
6A, 448A, 449B, 450B and 451B are adders, which add the signals shown in the drawing with the polarities shown.

The current commands I _U ^* , I _V ^* , and I _W ^* are exactly the same as the current command values obtained by the above-mentioned equation (9). Therefore, I _U ^* , I _W ^*
_When the current of the reactor part 300 of FIG. 1 is controlled on the basis of _V ^* and I _W ^* , exactly the same compensation effect as that of the invention shown in FIGS. 1 and 2 can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 417C, 418C and 419C in FIG. 4 can be simplified and the cost can be reduced as compared with the arithmetic units 417A, 418A and 419A in FIG.

Further examples of the present invention are as follows. That is, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 shows a modified example of the distributor 415A of FIG. 2 of the invention, which is inserted and used in the distributor 415A of FIG. The same symbols in FIGS. 5 and 1 are connected according to the symbols.

In FIG. 5, 422E is a two-phase generator, which receives the phase angle signal ▲ θ ^* _1d1 ▼ like the invention of FIG. 2 and receives the unit two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ shown in the equation (18). e ^* _1q2 ▼ is generated. Signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ is the signal obtained by the equation (5) Description ▲ e ^* _1d2 ▼, is the same as the _▲ e ^* 1q2 ▼. 423E is a calculator, the signal Q _1PA, P _1PA and _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ enter a, calculated by the signal P _1ND (phase negative sequence current signal of the first phase of the formula (19) ), Q _1ND (first-phase 90 ° reverse-phase current signal) is output. Signal P _1ND , Q
_1ND is the same as the signals P _1ND and Q _1ND obtained by the equation (6) described above.

Next, 424E and 425E are arithmetic units, which input the signals P _1ND and Q _1ND and perform the arithmetic operations of the equations (20) and (21) respectively to output the signals Q _2ND and P
_{Outputs 2ND} , Q _3ND and P _3ND .

Here, P _2ND is the second-phase in-phase and reverse-phase current signal, and Q _2ND is the second
90 ° anti-phase current signal of the phase, P _3ND is the in-phase anti-phase current signal of the third phase, Q _3ND is the 90 ° anti-phase current signal of the third phase, and these signals are expressed by the equation (7) ( The signal P _2ND obtained in 8),
It is the same as Q _2ND , P _3ND , and Q _3ND .

A setter 447 outputs a reactive current setting signal Q _1MAX . Reference numeral 440A denotes a distributor, which has a positive-phase reactive current signal Q _1PD and first-phase, second-phase, and third-phase in-phase negative-phase current signals P _1ND , P _2ND , P _3ND , and a 90 ° negative-phase current signal Q. _1ND ,
_Input Q _2ND , Q _3ND , and reactive current setting signal Q _1MAX ,
Based on these signals, the calculation of the equation (9) described above is performed, and the first-phase, second-phase, and third-phase current commands I _U ^* , I _V ^* , I
Output _W ^* . Here, the distributor 440A of FIG.
Has the same configuration as that of the distributor 440A shown in FIG.

The current command value _{^{I U *, I V *,}} I W * the second current command value obtained in Figure I _U described above explained ^*, I _V ^*, are of exactly the same as I _W ^*, thus the I _U ^If the current of the reactor part 300 shown in FIG. 8 is controlled based on ^* , I _V ^* , and I _W ^* ,
The exactly same compensation effect as the invention according to FIGS. 1, 2 and 3 can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 424E and 425E shown in FIG. 5 can be simplified as compared with the arithmetic units 418A and 419A shown in FIG. 2, and the cost can be reduced accordingly.

Further examples of the present invention are as follows. That is, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows a modified example of the distributor 415A of FIG. 2 of the above invention, which is inserted and used in the distributor 415A of FIG. 6 and FIG. 1 are connected according to the same symbols.

In FIG. 6, 422E is a two-phase generator, which receives the phase angle signal ▲ θ ^* _1d1 ▼ like the invention of FIG. 2 and receives the unit two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ shown in the equation (18). e ^* _1q2 ▼ is generated. Signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ is the signal obtained by the equation (5) Description ▲ e ^* _1d2 ▼, is the same as the _▲ e ^* 1q2 ▼. 423E is a calculator, the signal Q _1PA, P _1PA and _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ enter a, calculated by the signal P _1ND (phase negative sequence current signal of the first phase of the formula (19) ), Q _1ND (first-phase 90 ° reverse-phase current signal) is output. Signal P _1ND , Q
_1ND is the same as the signals P _1ND and Q _1ND obtained by the equation (6) described above.

Next, 424F and 425F are arithmetic units, which receive the signals P _1ND and Q _1ND , respectively, perform the calculations of the equations (22) and (23), and output the signals Q _2ND and Q _3ND .

Here, Q _2ND is the second-phase 90 ° negative-phase current signal, and Q _3ND is the third-phase 90 ° negative-phase current signal. These signals are obtained by the equations (7) and (8) described above. The signals Q _2ND and Q _3ND are the same.

A setter 447 outputs a reactive current setting signal Q _1MAX . 440B is a distributor, which is a positive-phase reactive current signal Q _1PD , and 90 ° negative-phase current signals Q _1ND , Q _2ND , Q _{3ND of} the first phase, the second phase, and the third phase, and a reactive current setting signal Q. _1MAX is input, the above-mentioned equation (13) is calculated based on these signals, and the first-phase, second-phase, and third-phase current commands I _U ^* , I
Outputs _V ^* and _IW ^* . Here, the distributor 440B of FIG. 6 of the present modification has the same configuration as the distributor 440B of FIG. 3 described above, and therefore the description of the elements is omitted.

The current command value _{^{I U *, I V *,}} I W * the second current command value obtained in Figure I _U described above explained ^*, I _V ^*, are of exactly the same as I _W ^*, thus the I _U ^If the current of the reactor part 300 shown in FIG. 8 is controlled based on ^* , I _V ^* , and I _W ^* ,
The same compensation effect as the invention according to FIGS. 2 and 3 can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 424F and 425F shown in FIG. 6 can be simplified as compared with the arithmetic units 418A and 419A shown in FIG.

Further examples of the present invention are as follows. That is, the sixth embodiment of the present invention will be described with reference to FIG. FIG. 7 shows a modified example of the distributor 415A of FIG. 2 of the above invention, which is inserted and used in the distributor 415A of FIG. 7 and FIG. 1 are connected in accordance with the same symbols.

In FIG. 7, 422E is a two-phase generator, which receives the phase angle signal ▲ θ ^* _1d1 ▼ like the invention of FIG. 2 and receives the unit two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ shown in the equation (18). e ^* _1q2 ▼ is generated. Signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ is the signal obtained by the equation (5) Description ▲ e ^* _1d2 ▼, is the same as the _▲ e ^* 1q2 ▼. 423E is a calculator, the signal Q _1PA, P _1PA and _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ enter a, calculated by the signal P _1ND (phase negative sequence current signal of the first phase of the formula (19) ), Q _1ND (first-phase 90 ° reverse-phase current signal) is output. Signal P _1ND , Q
_1ND is the same as the signals P _1ND and Q _1ND obtained by the equation (6) described above.

Next, 424G and 425G are arithmetic units, which input the signals P _1ND and Q _1ND , perform the arithmetic operations of the equations (24) and (25), respectively, and output the signals P _2ND and P _3ND .

Here, P _2ND is a second-phase in-phase reverse-phase current signal, P _3ND is a third-phase in-phase reverse-phase current signal, and these signals are signals obtained by the above-described equations (7) and (8). It is the same as P _2ND and P _3ND .

A setter 447 outputs a reactive current setting signal Q _1MAX . 440C is a sorting device, the positive-phase reactive current signal Q _1PD, and the first phase, second phase, third phase of the in-phase reverse-phase current signals _{P 1ND, P 2ND, P 3ND} , and reactive current setting signal Q _1MAX
Is input, and the calculation of the above-described equation (17) is performed based on these signals, and the first-phase, second-phase, and third-phase current commands I _U ^* ,
I _V ^* and I _W ^* are output. Here, since the distributor 440C of FIG. 7 of the present modification has the same configuration as the distributor 440C of FIG. 4 described above, the description of the elements is omitted.

The current command value _{^{I U *, I V *,}} I W * the second current command value obtained in Figure I _U described above explained ^*, I _V ^*, are of exactly the same as I _W ^*, thus the I _U ^If the current of the reactor part 300 shown in FIG. 8 is controlled based on ^* , I _V ^* , and I _W ^* ,
The same compensation effect as the invention according to FIGS. 2 and 3 can be obtained.

As described above, in this embodiment, the arithmetic operations of the arithmetic units 424G and 425G shown in FIG. 7 can be simplified as compared with the arithmetic units 418A and 419A shown in FIG.
Therefore, the cost can be reduced.

〔The invention's effect〕

As is clear from the above description, the reactive power compensator of the present invention has the following effects. That is, (1) the current generated by a fluctuating load such as an arc furnace is an unbalanced current containing a large amount of positive phase components and a large amount of negative phase components, but in the present invention, these positive phase components and negative phase components are clearly defined. Since it can be detected separately, the target to be compensated by the reactive power compensator becomes clear, that is, the control focusing only on the positive phase reactive power, the control focusing only on the negative phase current, or the current balancing control (reverse control). Phase current compensation) is prioritized, and positive phase reactive power compensation is performed only when there is extra capacity in the device (priority control), etc. can be freely configured, and more advanced compensation control than the conventional one can be performed. Easy to achieve.

(2) Even if the load current fluctuates, the positive phase component and the negative phase component can be continuously detected in the form of a DC signal regardless of the lead power factor / lag power factor. Since it does not enter, stable compensation control can be realized.

(3) In the control circuit, when detecting the positive-phase component and the negative-phase component of the load current, simple elements such as a coefficient unit, an adder, and a multiplier are used as signal processing means to perform a simple calculation. It is possible to obtain an accurate and high-accuracy signal (regarding the positive phase component and the negative phase component) without any ambiguity in the detection signal, only by obtaining the required signal. In addition, the cost is low because the circuit is simple.

(4) Therefore, in the reactive power compensator according to the present invention, since the information regarding the positive-phase current and the negative-phase current is accurately separated and detected, therefore, even if the load fluctuates rapidly like an arc furnace, Since it is possible to perform control by clarifying the target of compensation (that is, whether to control the positive-phase reactive current, the negative-phase current, etc.), stable and highly accurate reactive power compensation can be performed.

As described above, the reactive power compensator of the present invention incorporates a completely new control concept that "the positive phase component and the negative phase component are separately detected and the compensation control is performed based on that" which is not in the conventional control. Therefore, it is possible to sufficiently meet the demand for the reactive power compensation control which will be complicated and sophisticated in the future.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 to 7 are block diagrams showing different embodiments of the present invention, and FIG. 8 is a reactive power to which the present invention is applied. FIG. 9 is a main circuit diagram of the compensator, and FIG. 9 is a block diagram of a reactive power detection circuit conventionally used in a conventional reactive power compensator. 1 ... AC power supply system, 3 ... system impedance, 9,
10 ... Arc furnace equipment, 100 ... Reactive power compensation device,
200 ... Phase advancing capacitor, 300 ... Reactor section,
350 ... control circuit, 400 ... arithmetic circuit, 500 ...
Firing control circuit, 402 ... Line / phase converter, 403 ... 2
Phase converter, 404 ... Calculator, 405 ... 2-phase generator,
408,409 …… DC detection filter, 410,411 …… Adder, 4
15A ... Distributor, 500 ... Ignition controller, 416A, 422E
...... 2-phase generator, 417A to 419A, 471B to 419B, 417C to 419C, 4
23E, 424E, 425E, 424F, 425F, 424G, 425G ... Calculator, 441A
〜443A 、 453B〜455B …… Coefficient multiplier, 444A〜446A 、 448A〜45
1A, 449B to 451B ... Adder, 447 ... Setting device.

Claims (7)

[Claims] 1. A reactive power compensator for compensating unbalanced power and reactive power generated by a load connected to a multi-phase AC power supply system, wherein a phase is synchronized with a first phase voltage of an N-phase poly-phase AC power supply. Unit sine wave signal ▲ e ^* whose angle changes as ▲ θ ^* _1d1 ▼
_1d1 ▼ and, means for obtaining a unit sine wave signal _▲ e ^* 1q1 ▼ varying delays from 90 ° phase it, N-phase multi-phase load current i _1L, detects the i _2L ... i _NL, the first phase Two-phase current signal i
_{1 dL,} means for obtaining i _1QL, the signal _{^{▲ e * 1d1 ▼, ▲ e}} * 1q1 ▼ and i _{1 dL,} P _1P using _{^{i 1qL = ▲ e * 1d1 ▼}} · i 1dL + ▲ e * 1q1 ▼ · i _1qL Q _1P = ▲ e ^* _1d1 ▼ ・ i _1qL − ▲ e ^* _1q1 ▼ ・ i _1dL to obtain the signals P _1P and Q _1p , and the AC component of the signals P _1p and Q _{1p 1PA} ,
A means for extracting the DC components of Q _1PA and Q _1p to obtain a signal Q _1PD , and a calculation of N-phase / multi-phase AC using the signals ▲ θ ^* _1d1 ▼, Q _1PD , P _1PA , Q _1PA as input signals. A reactive power compensator comprising: means for generating current commands for the first phase, second phase to Nth phase, and controlling the reactive power compensator based on the current command obtained by the means. 2. A means for creating the current command, means for setting a reactive current setting signal Q _1MAX for instructing the maximum value of the reactive power to be compensated by the reactive power compensator, and the phase angle signal ▲ theta ^* _1d1 operates based on ▼, phase angle 2 ▲ theta ^* _1d1 unit sine wave signal varies ▼ ▲ e ^* _1d2 ▼ the unit sine wave signal delayed from the 90 ° phase it _▲ e ^* 1q2 ▼,
And the two-phase unit sine wave signals ▲ e ^* _2d2 ▼, ▲ e ^* _2q2 ▼, and similarly the phase changes by (2 ▲ θ ^* _1d1 ▼ + 2 / 3π) and (2 ▲ θ ^* _1d1 ▼). -2 / 3π) changes 2
Unit sine wave signal phase _{^{▲ e * 3d2 ▼, ▲ e}} * 3q2 ▼ to obtain means and the signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼, ▲ e * 2d2 ▼, ▲ e *
_2q2 ▼, ▲ e ^* _3d2 ▼, ▲ e ^* _3q2 ▼ and signals P _1PA , Q _{1PA
^{P 1ND = ▲ e * 1d2 ▼}} · P 1PA based on the _{^{- ▲ e * 1q2 ▼ · Q}} 1PA Q 1ND = ▲ e * 1d2 ▼ · Q 1PA + ▲ e * 1q2 ▼ · P 1PA P 2ND = ▲ e * 2d2 ▼ ・ P _1PA − ▲ e ^* _2q2 ▼ ・ Q _1PA Q _2ND = ▲ e ^* _2d2 ▼ ・ Q _1PA + ▲ e ^* _2q2 ▼ ・ P _1PA P _3ND = ▲ e ^* _3d2 ▼ ・ P _1PA − ▲ e ^* _3q2 ▼・ Q _1PA Q _3ND = ▲ e ^* _3d2 ▼ ・ Q _1PA + ▲ e ^* _3q2 ▼ ・ P _1PA is calculated and signals P _1ND , Q _1ND , P _2ND , Q _2ND ,
_Means for obtaining P _3ND , Q _3ND , said signals Q _1MAX , Q _1PD , Q _1ND , Q _2ND , Q _3ND ,
Based on P _1ND , P _2ND , P _3ND The means for calculating the current command signals I _U ^* , I _V ^* , and I _W ^*, and the reactive power compensator according to claim 1. 3. A means for generating the current command, means for setting a reactive current setting signal Q _1MAX for instructing the maximum value of the reactive power to be compensated by the reactive power compensator, and the phase angle signal ▲ theta ^* _1d1 operates based on ▼, phase angle 2 ▲ theta ^* _1d1 unit sine wave signal varies ▼ ▲ e ^* _1d2 ▼ the unit sine wave signal delayed from the 90 ° phase it _▲ e ^* 1q2 ▼,
Similarly, the two-phase unit sine wave signals ▲ e ^* _2d2 ▼, ▲ e ^* _2q2 ▼, which similarly change the phase by (2 ▲ θ ^* _1d1 ▼ + 2 / 3π), and the phase (2 ▲ θ ^* _1d1 ▼ -2 / _3π) unit sine wave signals of two phases which changes in _{^{▲ e * 3d2 ▼, ▲ e}} * 3q2 ▼ means for obtaining the signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼, ▲ e * _2d2 ▼, ▲ e ^{*
_{2q2 ▼, ▲ e * 3d2 ▼}} , ▲ e * 3q2 ▼ and P _1PA, Q based on the _{^{Q 1PA 1ND = ▲ e * 1d2}} ▼ · Q 1PA + ▲ e * 1q2 ▼ · P 1PA Q 2ND = ▲ e * 2d2 ▼ ・ Q _1PA + ▲ e ^* _2q2 ▼ ・ P _1PA Q _3ND = ▲ e ^* _3d2 ▼ ・ Q _1PA + ▲ e ^* _3q2 ▼ ・ P _1PA The means to obtain the signals Q _1ND , Q _2ND and Q _3ND the signal _{Q 1MAX, Q 1PD, Q 1ND} , Q 2ND, I based on the _{^{Q 3ND * U = -Q 1MAX +}} Q 1PD -2Q 1ND I * V = -Q 1MAX + Q 1PD -2Q 2ND I * W = -Q The reactive power compensator according to claim 1, further comprising means for calculating _1MAX + Q _1PD -2Q 3ND and _creating current command signals I _U ^* , _IV ^* , and I _W ^*. . 4. A means for generating the current command, a means for setting a reactive current setting signal Q _1MAX for instructing a maximum value of reactive power to be compensated by the reactive power compensator, and the phase angle signal ▲ theta ^* _1d1 operates based on ▼, phase angle 2 ▲ theta ^* _1d1 unit sine wave signal varies ▼ ▲ e ^* _1d2 ▼ the unit sine wave signal delayed from the 90 ° phase it _▲ e ^* 1q2 ▼,
Also, a two-phase unit sine wave signal ▲ e ^* _2d2 ▼, ▲ e ^* _2q2 ▼, which similarly changes in phase by (2 ▲ θ ^* _1d1 ▼ + 2 / 3π), and similarly, phase (2 ▲ θ ^* _1d1 ▼) -2 / 3π) changes 2
Unit sine wave signal phase _{^{▲ e * 3d2 ▼, ▲ e}} * 3q2 ▼ means for obtaining the signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼, ▲ e * 2d2 ▼, ▲ e *
_{^{2q2 ▼, ▲ e * 3d2 ▼}} , ▲ e * 3q2 ▼ and P _1PA, P based on the _{^{Q 1PA 1ND = ▲ e * 1d2}} ▼ · P 1PA - ▲ e * 1q2 ▼ · Q 1PA P 2ND = ▲ e * 2d2 ▼ ・ P _1PA − ▲ e ^* _2q2 ▼ ・ Q _1PA P _3ND = ▲ e ^* _3d2 ▼ ・ P _1PA − ▲ e ^* _3q2 ▼ ・ Q _1PA means to obtain the signals P _1ND , P _2ND , P _3ND And based on the signals Q _1MAX , Q _1PD , P _1ND , P _2ND and P _3ND And a means for producing the current command signals I _U ^* , I _V ^* , I _W ^* , the reactive power compensator according to claim 1. 5. A means for creating the current command, means for setting a reactive current setting signal Q _1MAX for instructing a maximum value of reactive power to be compensated by the reactive power compensator, and the phase signal ▲ θ ^*. _Operates based on _1d1 ▼ and phase angle is 2 ▲
theta ^* _1d1 ▼ and unit sine wave signal _▲ e ^* 1q2 obtain ▼ means unit sine wave signal ▲ e ^* _1d2 ▼ and it than 90 ° phase change is delayed in the signal _{^{▲ e * 1d2 ▼, ▲ e}} * _1q2 ▼ and P _1PA, P based on the _{^{Q 1PA 1ND = ▲ e * 1d2}} ▼ · P 1PA - ▲ e * 1q2 ▼ · Q 1PA Q 1ND = ▲ e * 1d2 ▼ · Q 1PA + ▲ e * 1q2 ▼ · P signal P _1ND performs an operation of _1PA, means for obtaining the Q _1ND, the signal P _1ND, based on the Q _1ND To obtain the signals P _2ND , Q _2ND , P _3ND , Q _3ND , and the signals Q _1MAX , Q _1PD , Q _1ND , Q _2ND , Q _3ND ,
Based on P _1ND , P _2ND , P _3ND The means for calculating the current command signals I _U ^* , I _V ^* , I _W ^*, and the reactive power compensator according to claim 1. 6. A means for creating the current command, means for setting a reactive current setting signal Q _1MAX for instructing the maximum value of the reactive power to be compensated by the reactive power compensator, and the phase signal ▲ θ ^*. _Operates based on _1d1 ▼ and phase angle is 2 ▲
theta ^* _1d1 ▼ and unit sine wave signal _▲ e ^* 1q2 obtain ▼ means unit sine wave signal ▲ e ^* _1d2 ▼ and it than 90 ° phase change is delayed in the signal _{^{▲ e * 1d2 ▼, ▲ e}} * _1q2 ▼ and P _1PA, P based on the _{^{Q 1PA 1ND = ▲ e * 1d2}} ▼ · P 1PA - ▲ e * 1q2 ▼ · Q 1PA Q 1ND = ▲ e * 1d2 ▼ · Q 1PA + ▲ e * 1q2 ▼ · P signal P _1ND performs an operation of _1PA, means for obtaining the Q _1ND, the signal P _1ND, based on the Q _1ND Signal Q _2ND performs an operation of, the means for obtaining the Q _3ND, the signal _{Q 1MAX, Q 1PD, Q 1ND} , Q 2ND, based on the _{^{Q 3ND I * U = -Q 1MAX}} + Q 1PD -2Q 1ND I * V = -Q _1MAX + Q _1PD -2Q _2ND I ^* _W = -Q _1MAX + Q _1PD -2Q _3ND and means for generating current command signals I _U ^* , _IV ^* , I _W ^*. The reactive power compensator according to claim 1. 7. A means for creating the current command, means for setting a reactive current setting signal Q _1MAX for instructing a maximum value of reactive power to be compensated by the reactive power compensator, and the phase signal ▲ θ ^*. _Operates based on _1d1 ▼ and phase angle is 2 ▲
theta ^* _1d1 ▼ and unit sine wave signal _▲ e ^* 1q2 obtain ▼ means unit sine wave signal ▲ e ^* _1d2 ▼ and it than 90 ° phase change is delayed in the signal _{^{▲ e * 1d2 ▼, ▲ e}} * _1q2 ▼ and P _1PA, P based on the _{^{Q 1PA 1ND = ▲ e * 1d2}} ▼ · P 1PA - ▲ e * 1q2 ▼ · Q 1PA Q 1ND = ▲ e * 1d2 ▼ · Q 1PA + ▲ e * 1q2 ▼ · P signal P _1ND performs an operation of _1PA, means for obtaining the Q _1ND, the signal P _1ND, based on the Q _1ND Based on the signals Q _1MAX , Q _1PD , P _1ND , P _2ND , P _3ND , and means for obtaining the signals P _2ND , P _3ND The means for calculating the current command signals I _U ^* , I _V ^* , I _W ^*, and the reactive power compensator according to claim 1.