JPH0789715B2 - Reactive power compensator - Google Patents

Description

The present invention relates to a reactive power compensator, and more particularly to a power supply system that suppresses voltage fluctuations in an AC power supply system and suppresses voltage imbalance. The present invention relates to an effective reactive power compensator for stabilizing electric power.

(Prior Art) In recent years, loads such as AC trains that take single-phase power have come to be connected to a power supply system, and an unbalanced current and an impedance of the power supply system cause an unbalanced voltage in the power supply system. This is a problem that arises, and the fluctuation of the voltage due to the change of the reactive power of the power supply system has become a problem. Therefore, a reactive power compensator is installed in the power supply system to compensate the reactive power of the power supply system and suppress voltage fluctuations, and to compensate the unbalanced current of the power supply system and remove the unbalanced component of the voltage. Attempts are being made.

As for the power supply system equipped with such a reactive power compensator, for example, a paper “A system using SVC using a digital controller” presented at the Institute of Electrical Engineers and Power Technology Study Group in July 1985. The simulator test for stabilization "is described in detail, and the basic configuration is as shown in FIG.

That is, in the figure, 10 and 11 are power supply buses of branch lines to loads such as AC trains, 100 is a reactive power compensator, and is composed of a reactor unit 300 and a phase advance capacitor 200. Reactor unit 300 is composed of reactors 302U to 302W, anti-parallel thyristors 301U to 301W connected in series thereto, voltage detection transistor 70, and its control circuit 350, detects the voltage of power supply bus bar 6 and responds to the detected value. Thyristor
The conduction angle of 301U to 301W is adjusted to control the reactor current. 3 is an impedance existing in the three-phase AC power supply system, and 1 is a main line three-phase AC power supply system. Here, the power capacity (lag capacity) of the reactor 300 of the reactive power compensator 100
Is usually the power capacity of the phase advancing capacitor 200 (phase advancing capacity)
Therefore, as shown in FIG. 6, by changing the reactor current I _R from zero to the maximum, the power Q generated as the reactive power compensator 100 is changed from the advanced phase to the delayed phase. It can change smoothly.

In the power supply system having the above configuration, when the reactive current (or reactive power) of the bus 6 changes, the voltage of the bus 6 changes due to the action of the impedance and the impedance 3, and the unbalanced current generated by a single-phase load such as an electric train. Flowing into the bus bar 6, an imbalance occurs in the voltage of the bus bar 6 due to the action of the impedance 3.
A reactive power compensator is used to suppress and compensate such voltage fluctuations and voltage imbalances, but the performance of the device depends on how to detect voltage fluctuations and how to detect voltage imbalances. . An example of this control circuit is shown in FIG.

That is, FIG. 7 shows the gist of the description in the above-mentioned document. First, the bus voltage is detected individually for each phase (e _RS ,
e _ST , e _TR ), rectify it through an absolute value circuit (ABS),
It is passed through a filter circuit FIL to obtain DC signals e _DR , e _DS , e _DT . e _{DR to} e _DT are proportional to the voltage value between each line of the bus voltage. On the other hand, ▲ V ^* _R ▼ is a signal indicating the voltage value to be maintained by the AC bus, and this signal and signals e _DR , e _DS , and e _DT are compared with comparators CR and C
S, CT are compared individually, and the deviation is amplified by an amplifier AMP to make reactor current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼.
When the current of the reactor circuit 300 of FIG. 5 is controlled based on ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼, when the reactive power of the AC bus changes and the bus voltage changes, it becomes invalid. The power compensator 100 compensates for it and keeps the voltage constant, and
When an unbalanced current flows through the AC bus and an imbalance occurs in the voltage, the reactive power compensating device 100 compensates for it and operates in a direction to correct the voltage imbalance.

In addition, a reactive power compensator having various voltage detection methods has been proposed, but the gist thereof can be reduced to the method described in the above-mentioned document.

(Problems to be Solved by the Invention) The above is the description of the conventional reactive power compensating device, but this device has the following drawbacks. That is, the voltage fluctuation of the AC bus is caused by the change of the positive phase current (the positive phase voltage fluctuation).
, And an unbalanced component of voltage (negative phase voltage fluctuation) caused by negative phase current, but the conventional voltage detection method has no concept of clearly separating positive phase voltage fluctuation / negative phase voltage fluctuation. , Therefore, the voltage of the bus bar is regarded as a mere fluctuation component in which the positive and negative phase voltage fluctuations are mixed together.
The reactive power compensator is controlled based on it. Therefore, in the conventional reactive power compensator, what is to be compensated, that is, whether positive phase voltage fluctuation (particularly fluctuation due to positive phase reactive current) is controlled, or negative phase voltage fluctuation,
That is, it is impossible in principle to discriminate whether or not the unbalanced component of the voltage is controlled, and it has been impossible to develop a more advanced control.

In recent years, there has been a strong demand for improvement in the power quality of the AC power system, and the emergence of a power system capable of more advanced control, stabilization measures, and reactive power compensators has been sought. There is an urgent need to develop a reactive power compensator equipped with a highly accurate voltage detection method (positive-phase voltage fluctuation detection method, negative-phase voltage fluctuation detection method) based on various control concepts.

The present invention has been made in view of the above-mentioned problems of the prior art,
The purpose is to detect the voltage fluctuations of the power supply system separately in the positive phase component and the negative phase component in the device that compensates the voltage fluctuations of the AC power supply system and the unbalanced voltage, and clarify the compensation target. An object of the present invention is to provide a reactive power compensator capable of performing highly accurate voltage compensation control by performing control.

[Structure of the Invention] (Means for Solving Problems) The outline of the present invention will be described with reference to FIGS. 1 and 2. The system voltage is detected and led to elements 403 and 406 in FIG. In 406, a unit two-phase voltage signal synchronized with the system voltage is generated.
Then, a unit two-phase voltage signal having a frequency twice the system voltage is created. On the other hand, in 403, the three-phase voltage signal is converted into a two-phase signal. The signals of 403 and 406 are led to the element 404, and the instantaneous power signal is calculated. The element 409 separates the output signal of 404 into a direct current component (first-phase negative-phase voltage signals P _1ND , Q _1ND ) and an alternating current component (P _1NA , Q _1NA ). In 408, by the signal of 407 and the AC component signal of 409,
Calculate the positive phase fundamental wave voltage signal ( _P1PD ). The contents of element 420A are shown in FIG. 412A of FIG. 2, 424A in the signal P _1ND, Q
_{Using 1ND} , the reverse phase voltage signals (P _2ND ,
_Calculate Q _2ND ), (P _3ND , Q _3ND ). 437 sets the voltage value of the power supply system to be held. Signal P _1PD , P for 430A
_The voltage deviation signals ΔE _U , ΔE _V , and ΔE _W are calculated using _1ND , Q _1ND , P _2ND , Q _2ND , P _3ND , and Q _3ND . Amplifier 451U, 451V, 451W,
When the signals ΔE _U , ΔE _V , and ΔE _W are amplified, the reactor current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼ are obtained, and the reactive power compensator is controlled based on these.

( _Operation ) When the above control circuit is used, the system voltage information is for positive phase (P _1PD ) and negative phase (P _1ND , Q _1ND , P _2ND , Q _2ND , P _3ND , Q _3ND )
Are clearly separated and detected. Therefore, by controlling the reactive power compensator by these signals, the object of compensation can be clarified and a highly accurate device can be realized.

(Embodiment of the Invention) A power supply system equipped with a reactive power compensator of the present invention (for convenience of the following description, a three-phase system will be described) is the same as that shown in FIG. The description of the elements referred to in 1 is omitted here.

In FIG. 5, a voltage detector 70 detects the line voltage (e _RS , e _ST , e _TR ) of the AC bus 6 to be compensated and guides it to the control circuit 350. 300 is a reactor part, 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.

400 is an arithmetic circuit incorporating the present invention, the voltage signal e _RS, e
Input _ST and e _TR , perform various calculations, and set the direct current value command ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼ for instructing the fundamental current that the reactor unit 300 should flow. Output.

500 is an ignition controller, which is a current command value ▲ I ^* _U ▼, ▲ I ^* _V
Operates in response to ▼, ▲ I ^* _W ▼, ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲
The current (fundamental wave component) indicated by I ^* _W ▼
The thyristors 301U, 301V, 301W are controlled so that 2U, 302V, 302W will flow.

The control circuit is a combination of the arithmetic circuit 400 and the ignition controller 500.
Referred to as 350, 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 FIG. 1, the AC bus voltage signals e _RS , e _ST , e of FIG.
_TR is input to the two-phase converter 403 and the two-phase signal generator 406. In the two-phase converter 403, the voltage signals e _RS , e _ST , e _TR are converted into two-phase voltage signals e _1ds , e _1qs by the calculation of the equation (1). The two-phase signal generator 406 is composed of a phase lock loop circuit, receives the voltage signals e _RS , e _ST , e _TR, and outputs the first phase of FIG. 5 as the R phase and the second phase. S phase,
If the third phase is the T phase, the line voltage e _{RS of} the first phase and the second phase
The unit sine wave signal ▲ e ^* _1d1 ▼ synchronized with, the unit sine wave signal ▲ e ^* _1q1 ▼ advanced by 90 °, and its phase signal ▲ θ ^* _1d1 ▼ are output to ▲ e ^* _1d1 ▼, ▲ e ^* _1q1 ▼ can be expressed by equation (2).

407 is also a two-phase generator, operates in response to the phase angle signal ▲ θ ^* _1d1 ▼, and has a frequency twice that of the AC bus voltage frequency. The two-phase voltage signal ▲ e ^* _1d2 ▼, ▲ e ^* _{Generates 1q2} ▼.

_{Reference numeral} 404 is a computing unit, which includes signals e _1ds , e _1qs and ▲ e ^* _1d1 ▼, ▲ e
^* _1q1 ▼ is input and the signals Q _1N and P _1N are calculated by the equation (4).

If the system voltages e _RS , e _ST , e _TR include positive / negative phase components, P _1N , Q _1N becomes a pulsating flow that includes a DC component and an AC component that oscillates at twice the fundamental wave. .

The signals e _1ds and e _1d1 ^* are signals that change in almost the same phase, and the signals e _1qs and e _1q1 ^* are signals that change in opposite phases. Therefore, P _1N and Q _1N calculated by equation (4)
, The component relating to the positive-phase fundamental wave appears as an amount that changes by twice the fundamental wave, and the component relating to the negative-phase component appears as a DC amount. In the present invention, in order to detect the anti-phase component as the amount of direct current, the signal _source e _1q1 ^* having a phase almost opposite to that of e _1qs is used.

409 is a separator, 410, 411 DC detection filter and 412,
It is composed of 413 adder, inputs signals P _1N and Q _1N ,
The DC components of P _1N and Q _1N are detected by the DC detector filters 410 and 411 and are output as signals P _1ND and Q _1ND , and the adders 412 and 4
At the position of 13, the DC component, that is, P _1ND , Q _1ND is removed from the signals P _1N , Q _1N , and only the AC component is output as the signals P _1NA , Q _1NA . In P _1ND and Q _1ND thus obtained, the negative-phase voltage component contained in the first-phase and second-phase line voltage e _RS is in-phase with the positive-phase fundamental wave voltage of the first-phase and second-phase line voltage. Ingredient (P _1ND ) and
It shows the voltage of each component when it is decomposed into 90 ° phase difference components (Q _1ND ), where P _1ND is the first phase in-phase and opposite phase voltage signal, and Q _1ND is the first phase 90 ° opposite phase. We will call it the voltage signal.

408 is a computing element signal P _1NA, Q _1NA and ▲ e ^* _1d2 ▼, ▲ e
^* _1q2 ▼ is input and the signal P _1PD is calculated from the equation (5).

^{_{P 1PD = ▲ e * 1d2 ▼}} · P 1NA + ▲ e * 1q2 ▼ · Q 1NA ... (5) signal P _1PD becomes a DC signal, the P _1PD is the system voltage e _RS, e
_ST, represents the positive phase fundamental voltages including the e _TR.

Reference numeral 420A denotes a distributor, which receives signals P _1PD , P _1ND , Q _1ND to perform calculation, and current command values ▲ I ^* _U ▼, ▲ I ^* _V for instructing the current flowing through the reactor unit 300 shown in FIG. Output ▼ and ▲ I ^* _W ▼. The details of the distributor 420A are shown in FIG.

500 is an ignition controller, which is a current command value ▲ I ^* _U ▼, ▲ I ^* _V
Operates in response to ▼, ▲ I ^* _W ▼, ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲
The current (fundamental wave component) indicated by I ^* _W ▼
Ignition control of thyristors 301U, 301V, 301W so that 300 flows.

Next, the distributor 420A will be described with reference to FIG. Figure 1 and 2
Signals with the same symbols in the figure are connected according to the signals. Second
In the figure, 421A and 424A are arithmetic units, which input the 90 ° anti-phase voltage signal Q _1ND of the first phase and the in-phase anti-phase voltage signal P _1ND of the first phase, respectively, and use the equations (6) and (7) respectively. Second through calculation
90 ° out-of-phase voltage signal Q _2ND of phase, in-phase out-of-phase voltage signal of second phase
It outputs P _2ND, the third-phase 90 ° negative-phase voltage signal Q _3ND , and the third-phase in-phase negative-phase voltage signal P _3ND .

Here, P _2ND and Q _2ND are the in-phase components of the line voltage e _ST of the second phase and the third phase, and the in-phase component of the positive phase fundamental wave component of the line voltage of the second and third phases, respectively. It shows the in-phase component voltage (P _2ND ) when decomposed into 90 ° phase different components, and the 90 ° different phase voltage component (Q _2ND ).

Similarly, P _3ND and Q _3ND are the in-phase _components of the third-phase and first-phase line voltage e _{TR and} the in-phase component of the positive-phase fundamental wave component of the third-phase and first-phase line voltage, respectively. It _shows the in-phase component voltage (P _3ND ) when decomposed into 90 ° phase different components, and the 90 ° different phase voltage component (Q _3ND ).

A setter 437 outputs a voltage setting signal ▲ E ^* _REF ▼ for instructing the voltage to be maintained on the AC bus 6 in FIG.

430A is a distributor, in which the positive phase fundamental wave voltage signal P _1PD detected from the AC bus voltage, the first phase, the second phase, the third phase
_Input the 90 ° reverse phase voltage signal Q _1ND , Q _2ND , Q _3ND of the phase and the reverse phase voltage signal P _1ND , P _2ND , P _{3ND of the} same phase and the voltage setting signal ▲ E ^* _REF ▼, and formula based on these signals. The calculation of (8) is performed and the voltage deviation signals ΔE _U , ΔE _V , and ΔE _W are output.

451U, 451V, and 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , and ΔE _W and output the result as a signal ▲ I ^* _U
Output as ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼. The signals ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼ obtained here are respectively used to indicate the current to be generated by the reactor 302U of the first phase of the reactor unit 300 shown in FIG. One-phase current command ▲ I ^* _U ▼,
And second phase current command for reactor 302V as well
I _V ^* , and 3rd phase current command for reactor 302W ▲
I ^* _W ▼.

Here, the following elements are included in the distributor 430A. That is, 431A, 432A, 433A are coefficient multipliers, And output. 434A, 435A, 436A are adders and coefficient units 43
Add the outputs of 1A, 432A, and 433A with the polarities shown. Adder 43
The outputs of 4A, 435A, and 436A correspond to the calculation of the third term of Expression (8). 438A is an adder, which is a setting signal ▲ E ^* _REF ▼ and signal P _1PD
Is calculated with the polarity shown. That is, the output of the adder 438A corresponds to the calculation of the first term of Expression (8). Reference numerals 439A, 440A and 441A denote adders that add the signals P _1ND , P _2ND and P _3ND and the output signal of the adder 438A and the output signals of the coefficient multipliers 434A, 435A and 436A with the polarities shown.

Signals obtained by the above calculation ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W
The black triangle represents a DC amount signal, and this signal includes all the information about the positive phase voltage and the information about the negative phase voltage. Therefore, by controlling the reactor unit 300 of FIG. 5 based on these ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼,
The voltage fluctuation of the bus bar 6 caused by the positive-phase reactive current and the bus line impedance 3 generated by the branch line power supply systems 10 and 11 and the anti-phase current and the bus line impedance 3 generated by the power supply systems 10 and 11 in FIG. It is possible to freely stabilize and balance the imbalance of the voltage of the bus bar 6 caused by the.

The above is a typical configuration of the present invention.

First, in FIG. 5, the voltage of the AC bus is the signal e _RS , e _ST , e.
_Although detected as _TR , this voltage is usually an unbalanced voltage including a positive phase component and a negative phase component. This voltage is first introduced into the two-phase generator 406 and the two-phase signals ▲ e ^* _1d1 ▼, ▲ e ^* _1q1 ▼ and its phase angle signal ▲ θ ^* _1d1 ▼ based on the equation (2).
Is output. Here, the two-phase generator 406 outputs the voltage signals e _RS , e
It is adjusted to _respond only to the positive-phase fundamental wave components of _ST and e _TR , and therefore two-phase signals ▲ e ^* _1d1 ▼, ▲ e ^* _1q1 ▼ and ▲ θ ^*
_1d1 ▼ contains only information about the positive-phase fundamental of the voltage. Then the two-phase generator 407 2-phase signals based on the equation (3) receives the phase angle signal ^{_{▲ θ * 1d1 ▼ ▲ e *}} 1d2 ▼, ▲ e * 1q2
Generate ▼.

On the other hand, the voltage signals e _RS , e _ST , e _TR are introduced into the two-phase converter 403, converted by the equation (1), and the two-phase signals e _1ds , e _1qs
Is obtained.

Next, the arithmetic operation of the equation (4) is performed in the arithmetic unit 404 and the signals P _1N , P _1N
Of the DC component Q _1ND ,
Separated into P _1ND and AC component signals Q _1NA and P _1NA .

In the signals P _1ND and Q _1ND thus obtained, the negative-phase voltage component contained in the first-phase / second-phase line voltage e _RS is regarded as the positive-phase fundamental wave component of the first-phase / second-phase line voltage. The voltage of each component when decomposed into an in-phase component and a component that is 90 ° out of phase with it, that is, the in-phase reverse-phase voltage component (P _1ND ) of the first phase and the 90-phase of the first phase.
Represents the negative phase voltage component (Q _1ND ).

On the other hand, the arithmetic unit 408 the signal _{^{▲ e * 1d2 ▼, ▲ e}} * 1q2 ▼ and Q
_1NA, although P _1PD of calculation is performed DC signal of Equation (5) is obtained by the P _1NA, this signal represents the positive phase fundamental voltages included in the system voltage e _RS, e _ST, e _TR ing.

Next, in the distributor 420A of FIG. 2, the calculation of the equations (6) and (7) is performed in the calculators 421A and 424A, and the second-phase in-phase reverse-phase voltage P _2ND and 90 ° reverse-phase voltage Q _2ND , In-phase and out-of-phase voltage P of the 3rd phase
_3ND , 90 ° reverse phase voltage Q _3NM is obtained.

The signal P _1ND obtained as described above is the system voltage e _RS , e _ST ,
It is a signal related only to the positive-phase fundamental wave voltage contained in _eTR , and more specifically, a signal related to only the component in phase with the positive-phase fundamental wave voltage. In the calculation of various quantities related to the positive phase of the voltage, for example, the conversion of the expression (5), 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, focusing on the signals P _1ND , Q _1ND and P _2ND , Q _2ND and P _3ND , Q _3ND , these signals are related only to the negative phase component voltage contained in the system voltages e _RS , e _ST , e _TR. In addition, P _1ND , Q _1ND is a signal for P _2ND , Q _2ND only in the opposite phase of voltage e _RS.
Only the negative-phase-sequence component of e _ST, P _3ND, Q _3ND to a signal related only to the negative-phase-sequence component of the voltage e _TR, more particularly P _1ND, Q
_{Taking 1ND} as an example, P _1ND is the voltage component in phase with the positive-phase fundamental wave component of the line voltage in the negative-phase component of the voltage e _RS , and Q _1ND is 90 ° out of phase with the positive-phase fundamental wave voltage. It is a signal related only to the voltage component.

As mentioned above, all the information of the system voltages e _RS , e _ST , e _TR are separately detected in the form of DC signals P _1PD , P _1ND , P _2ND , P _3ND , Q _1ND , Q _2ND , Q _3ND . It will be clear.

The signal thus obtained is calculated along the equation (8) in the distributor 430A of FIG. 2 to generate the voltage deviation signals ΔE _U , ΔE _V , ΔE _W , which are amplified to obtain the current command ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲
I ^* _W ▼ is obtained.

If the reactor current of FIG. 5 is controlled based on the current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼, the reactive power compensator
The 100 works as follows.

For example, when a reverse-phase current flows in the system and voltage imbalance occurs, it is detected by the control circuit (P _1ND , Q _1ND ,
P _2ND , Q _2ND , P _3ND , Q _3ND ), based on which the reactor part 3
00 generates a compensating anti-phase current (which is generated so that the phase is exactly opposite to the anti-phase current injected from the load to the system) so as to cancel this, and therefore the impedance 3 of FIG. The reverse-phase current apparently does not flow there, and the voltage imbalance due to the reverse-phase current is eliminated. This compensation effect is
Amplifiers 451U and 451 in which the control circuit of FIG. 2 is composed of a proportional integrator
Since V, 451W is included, it is executed until the reverse phase voltage of the system becomes completely zero.

Next, when the reactive current flows through the system and the voltage of the system changes, it is detected by the control circuit (signal of FIG. 2).
P _1PD ), and the current of the reactor unit 300 is adjusted based on the result of comparison between it and the voltage setting value ▲ E ^* _REF ▼. For example, when the voltage of the system drops, the reactor current becomes small. Therefore, as can be seen from the explanation of FIG. 6, the current generated by the reactive current compensating device 100 becomes a phase advance and the voltage of the system 6 is raised ( The voltage rises when a phase-advancing current is passed through the inductance). When the voltage is about to rise, the reactive power compensator 100 acts to generate a delay current and lower the system voltage, so that the system voltage is maintained at the set value.

As is apparent from the above description, in the power supply system including the reactive power compensating device of the present invention, even if the voltage fluctuation caused by the fluctuation of the reactive power of the load is about to occur, it is also caused by the negative phase current. Even if voltage imbalances are generated, they are compensated by the reactive power compensator, so that it is possible to supply high-quality power with a small voltage fluctuation and balanced voltage.

The above is a typical embodiment of the present invention.

Next, another embodiment of the present invention will be described with reference to FIG. That is, FIG. 3 is a modification of the distributor 420A of FIG. 2 of the above-described invention, and FIG. 3 is inserted and used in the distributor 420A 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, 421B and 424B are arithmetic units, which input the above-mentioned first-phase 90 ° negative-phase voltage signal Q _1ND and the first-phase in-phase negative-phase current signal P _1ND , respectively, and respectively use equations (9), Through the operation of (10), the in-phase and in-phase voltage signal P _{2ND of} the second phase and the in-phase and anti-phase voltage signal P _3ND of the third phase are output. The P _2ND and P _3ND are the same as the signals P _2ND and P _3ND obtained by the equations (6) and (7) described above.

Reference numeral 437 denotes a setting device that outputs a voltage setting signal ▲ E ^* _REF ▼. 430B is a distributor, which is a positive-phase fundamental wave voltage signal P _1PD , first-phase, second-phase, and third-phase in-phase negative-phase voltages P _1ND , P _2ND , P _3ND, and a voltage setting signal ▲ E ^* _REF ▼ Is input and the equation (11) is calculated based on these signals, and the voltage deviation signals ΔE _U , ΔE _V ,
Output ΔE _W.

451U, 451V, 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , ΔE _W, and the current commands ▲ I ^* _U ▼ of the first phase, the second phase, and the third phase. , ▲ I ^* _V ▼, ▲ I ^* _W ▼ are output. Here, 446B, 447B and 448B are coefficient multipliers that double the input signal and output it. Further, reference numerals 438A, 439B, 440B, and 441B are adders, which add the illustrated signals with the illustrated polarities.

The current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼ are shown in FIG.
It is exactly the same as the current command value obtained in step 1. Therefore, if the current of the reactor part 300 in FIG. 5 is controlled based on these ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼, Done first
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 421B and 424B in FIG. 3 can be simplified as compared with the arithmetic units 421A and 424A in FIG.

Next, another embodiment of the present invention will be described with reference to FIG. This embodiment also relates to the modification of the above-mentioned invention shown in FIG. 2, and FIG. 4 is used by being inserted into the distributor 420A shown in FIG. Therefore, the description of the same parts as those of the above-mentioned invention will be omitted.

In FIG. 4, 421C and 424C are arithmetic units, which input the above-mentioned first-phase 90 ° negative-phase voltage signal Q _1ND and the first-phase in-phase negative-phase voltage signal P _1ND , respectively, and respectively use equations (12), Through the operation of (13), the 90 ° negative phase voltage signal Q _{2ND of} the second phase and the 90 ° negative phase voltage signal Q _3ND of the third phase are output. The Q _2ND and Q _3ND are the same as the signals Q _2ND and Q _3ND obtained by the equations (6) and (7) described above.

Reference numeral 437 denotes a setting device that outputs a voltage setting signal ▲ E ^* _REF ▼. 430C is a distributor, which is a positive-phase fundamental wave voltage signal P _1PD , first-phase, second-phase, and third-phase 90 ° negative-phase voltage signals Q _1ND , Q _2ND , Q
_{Input 3ND} and voltage setting signal ▲ E ^* _REF ▼, calculate formula (14) based on these signals, and calculate voltage deviation signal Δ
Outputs E _U , ΔE _V , and ΔE _W.

451U, 451V, 451W are amplifiers composed of a proportional / integrator, etc., which amplify the deviations ΔE _U , ΔE _V , ΔE _W, and current commands ▲ I ^* _U ▼ for the first phase, the second phase, and the third phase. , ▲ I ^* _V ▼, ▲ I ^* _W ▼ are output. Here, 431A, 432A, 433A are coefficient multipliers, And output. The 446B, 447B, and 448B are also coefficient units, which double the input signal and output it. Also, 438A, 439B, 440B, 441B, 434
A, 435A, and 436A are adders, which add the illustrated signals with the illustrated polarities.

The current commands ▲ I ^* _U ▼, ▲ I ^* _V ▼, ▲ I ^* _W ▼ are exactly the same as the current command values obtained in FIG.
When the current of the reactor unit 300 of FIG. 1 is controlled based on I ^* _U ▼, ▲ I ^* _V ▼, and ▲ I ^* _W ▼, the above-described FIGS.
The same compensation effect as the invention according to the figure can be obtained.

As described above, in the present embodiment, the arithmetic operations of the arithmetic units 421C and 424C in FIG. 4 can be simplified as compared with the arithmetic units 421A and 424A in FIG.

[Effects of the Invention] As is clear from the above description, the reactive power compensator of the present invention has the following effects.

That is, (1) When a fluctuating load or an unbalanced load is connected to the AC power supply system, voltage fluctuations and voltage imbalances on the AC bus become problems, but in the present invention, these fluctuations are due to the positive phase component. Since it can be clearly separated and detected whether it is due to the reverse phase component,
Clarify what the reactive power compensator will cover,
Therefore, control focusing only on the voltage fluctuation of the system (voltage fluctuation suppressing control), control focusing only on the unbalanced voltage of the system (voltage balancing control), control focusing on both of them, etc. can be freely configured. It is possible to easily realize more sophisticated voltage compensation control than the conventional one.

(2) The positive and negative phase components of the system voltage can be continuously detected in the form of a DC signal, and therefore discontinuity does not enter into the control, so that stable control can be realized.

(3) In the control circuit, when the positive phase component and the negative phase component of the voltage are detected, simple elements such as a coefficient multiplier, an adder, and a multiplier are used as signal processing means to perform simple calculation. Therefore, it is possible to obtain an accurate and highly accurate signal (regarding the positive phase component and the negative phase component) without any ambiguity in the detection signal. Also, because the circuit is simple,
The cost will be lower.

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 them" which is not in the conventional control. Therefore, it is possible to sufficiently meet the demands for the reactive power compensation control which will become more 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 4 are block diagrams showing different embodiments of the present invention, and FIG. 5 is a reactive power compensation to which the present invention is applied. FIG. 6 is a main circuit diagram of the device, FIG. 6 is an operation explanatory diagram of the reactive power compensating device, and FIG. 7 is a block diagram of a voltage control circuit adopted in a conventional reactive power compensating device. 1 ... Main line AC power supply system, 3 ... System impedance, 10, 11 ... Branch AC power supply system, 100 ... Reactive power compensator, 200 ... Advancing capacitor, 300 ... Reactor section, 350 ... Control circuit, 400 ... Operation circuit, 500 ... Firing control circuit, 403 ... Two-phase converter, 404, 408 ... Operation unit, 40
6,407 …… 2-phase generator, 409 …… Separator, 410,411 …… DC detection filter, 412,413 …… Adder, 420A …… Distributor, 500 …… Ignition controller, 421A, 424A, 421B, 424B, 421C , 42
4C ... Calculator, 430A, 430B, 430C ... Distributor, 431A-433
A, 446B to 448B …… Coefficient unit, 437 …… Setting unit, 434A to 436A,
438A ~ 441A, 439B ~ 441B ... Adder, 451U, 451V, 451W ...
…amplifier.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 6260012 (JP, A) JP 6260013 (JP, A) JP 6260014 (JP, A) JP 62- 60015 (JP, A)

Claims (4)

[Claims] 1. A reactive power compensator for compensating for unbalanced voltage and voltage fluctuation in an N-phase multi-phase AC power supply system, wherein the phase is θ _1d1 ^* in synchronization with the voltage of the first phase of the N-phase AC power supply ^.
In the change unit sine wave signal e _1Q1 which ^* means for obtaining it from unit sine wave signal changes progressed 90 degree phase e _1Q1 ^*, N-phase AC power supply line voltages e _1S of, e _2S ... e _NS detects the d-axis taking it from the 90-degree direction in which the phase is delayed in accordance with the voltage e _1S of the first phase takes q-axis, the line voltage e _1S of the respective,
Signals e _1ds are obtained by projecting and combining e _2S ... e _NS on the d-axis, and projecting and combining the respective line voltages e _1S , e _2S ... e _NS on the q-axis to obtain a signal e _1qs . In the case of the means, that is, the case where the N-phase AC power supply has three phases, the line voltages e _1S , e _2S , e _3S are detected and the detected signals are used. _Means for obtaining the calculated values e _1ds , e _1qs of P _1N = e _1d1 ^*・ e _1ds + e _1q1 ^*・ e _1qs Q _1N = e by using the signals e _1d1 ^* , e _1q1 ^* and e _1ds , e _{1qs 1d1} ^*・ e _1ds −e _1q1 ^*・ e _1qs means for obtaining the calculated values P _1N , Q _1N , and detecting the AC components of the signals P _1N , Q _1N to obtain the signals P _1NA , Q _1NA , and , P _1N , Q _1N , that is, the negative phase voltage included in the first-phase line voltage e _1S of the N-phase AC power supply is in phase with the positive-phase fundamental wave component of the first-phase line voltage e _1S. Signal P decomposed into
Signal Q decomposed into _1ND and its 90 ° phase difference component
Means for obtaining _1ND , and operating based on the phase angle signal θ _1d1 ^* , and having a phase angle of 2
theta _1d1 ^* units varies with a sinusoidal signal e _1d2 ^* therewith than 90
Means for obtaining a degree phase delayed unit sine wave signal _e 1q2 ^*, the signal _{e 1d2} ^*, e 1q2 ^* and P _1NA, P based on the ^{_{Q 1NA 1PD = e 1d2 * ·}} P 1NA + e 1q2 * · Q 1NA The line voltage of each of the N-phase multi-phase AC power supplies e _1S , e
_2S … e _NS means for obtaining a signal P _1PD representing the positive phase fundamental wave voltage, means for setting a voltage setting signal E _REF ^* for indicating the voltage value of the power supply system to be maintained, and E _REF ^* , P _1PD ,
P _1ND , Q _1ND are used as input signals to perform a calculation to create a voltage deviation signal, and means for amplifying the signal to create an N-phase current command, based on the current command obtained by the means. The reactive power compensator is characterized by controlling the reactive compensator. 2. A means for generating the current command, means for setting a system voltage setting signal E _REF ^* for indicating a voltage value of a power supply system to be maintained by the action of the reactive power compensator, and the signal P. Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
And a signal Q _2ND reverse phase voltage decomposed into different components of the positive phase fundamental wave component and the signal decomposed into components in-phase P _2ND and therewith 90 degree phase of the second phase line voltage e _2S, including the _2S, said A signal P _{3ND obtained} by decomposing the negative phase voltage included in the third-phase line voltage e _3S of the N-phase AC power supply into a component in phase with the positive-phase fundamental wave component of the third-phase line voltage e _3S , and 90 ° with it _Means for obtaining a signal Q _3ND decomposed into components having different phases, and the signals E _REF ^* , P _1PD , P _1ND , Q _2ND , Q _3ND , P _1ND , P _2ND , P _3ND
On the basis of And the signal ΔE _U which is the deviation between the voltage setting signal E _REF ^* and the first-phase line voltage e _1S of the N-phase AC power supply, the voltage setting signal E _REF ^* and the N-phase AC a signal Delta] E _V is the difference between the line voltage e _2S of the second phase of the power supply, the voltage setting signal E _REF ^* and the deviation in a signal of the line voltage e _3S of the third phase of the N-phase AC power supply Means for creating ΔE _W, and a current that amplifies the signals ΔE _U , ΔE _V , and ΔE _W and indicates a current to be generated by the power unit of the reactive power compensator corresponding to the first phase of the N-phase AC power supply. The command signal I _U ^* , the current command signal I _V ^* for instructing the current to be generated by the power section of the reactive power compensator corresponding to the second phase of the N-phase AC power supply, and the third phase of the N-phase AC power supply A means for producing a current command signal I _W ^* for instructing a current to be generated by the power section of the corresponding reactive power compensator. 2. A reactive power compensator according to claim 1. 3. A means for generating the current command, means for setting a system voltage setting signal E _REF ^* for indicating the voltage value of the power system to be maintained by the action of the reactive power compensator, and the signal P Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
A signal P _2ND of the reverse-phase voltage is decomposed into positive phase fundamental wave component and a phase component of the line voltage e _2S of the second phase containing the _2S, line voltage of the third phase of the N-phase AC power source e _{3S Means} for obtaining a signal P _3ND by decomposing the negative-phase voltage included in the signal into a component in phase with the positive-phase fundamental wave component of the line voltage e _3S of the third phase, and the signal E _REF ^* , P _1PD , P _1ND , P Based on _2ND and P _3ND , ΔE _U = -E _REF ^* + P _1PD + 2P _1ND ΔE _V = -E _REF ^* + P _1PD + 2P _2ND ΔE _W = -E _REF ^* + P _1PD + 2P _3ND , and the voltage setting signal E _REF ^* and the signal Delta] E _U is a deviation between the line voltage e _1S N-phase alternating current first phase of the power supply, the voltage setting signal E _REF ^* and the line voltage of the N-phase AC second phase of the power source e Means for generating a signal ΔE _V which is a deviation from _2S, and a signal ΔE _W which is a deviation between the voltage setting signal E _REF ^* and the line voltage e _3S of the third phase of the N-phase AC power supply; Amplifies the signals ΔE _U , ΔE _V , ΔE _W , A current command signal I _U ^* instructing a current to be generated by the power section of the reactive power compensator corresponding to the first phase of the N-phase AC power supply, and a reactive power compensator corresponding to the second phase of the N-phase AC power supply Current command signal I _V ^* for instructing the current to be generated by the power section of the power supply and the current command signal I _W for instructing the current to be generated by the power section of the reactive power compensator corresponding to the third phase of the N-phase AC power supply The reactive power compensator according to claim 1, further comprising means for creating ^* . 4. A means for generating the current command, a means for setting a system voltage setting signal E _REF ^* for instructing a voltage value of a power system to be maintained by the action of the reactive power compensator, and the signal P. Based on _1ND , Q _1ND And the line voltage e of the second phase of the N-phase AC power supply is calculated.
Signal Q obtained by decomposing the inverse phase voltages including the _2S to different components of the positive phase fundamental wave component and a 90-degree phase of the line voltage e _2S of the second phase
_2ND, and a negative phase voltage included in the third-phase line voltage e _3S of the N-phase AC power supply is decomposed into a positive phase fundamental wave component of the third phase line voltage e _{3S and} a component having a phase difference of 90 degrees. _Means for obtaining a signal Q _3ND , based on said signals E _REF ^* , P _1PD , Q _1ND , Q _2ND , Q _3ND And the signal ΔE _U which is the deviation between the voltage setting signal E _REF ^* and the first-phase line voltage e _1S of the N-phase AC power supply, the voltage setting signal E _REF ^* and the N-phase AC a signal Delta] E _V is the difference between the line voltage e _2S of the second phase of the power supply, the voltage setting signal E _REF ^* and the deviation in a signal of the line voltage e _3S of the third phase of the N-phase AC power supply Means for creating ΔE _W, and a current that amplifies the signals ΔE _U , ΔE _V , and ΔE _W and indicates a current to be generated by the power unit of the reactive power compensator corresponding to the first phase of the N-phase AC power supply. The command signal I _U ^* , the current command signal I _V ^* for instructing the current to be generated by the power section of the reactive power compensator corresponding to the second phase of the N-phase AC power supply, and the third phase of the N-phase AC power supply A means for producing a current command signal I _W ^* for instructing a current to be generated by the power section of the corresponding reactive power compensator. 2. A reactive power compensator according to claim 1.