JPS59213234A - Effective and reactive power control system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to an active and reactive power control system for two voltage type inverters that are connected to a power system and perform parallel operation (system series operation). .

That is, it is effective to use an inverter system consisting of two groups of inverters as a system that takes as input a power source such as a fuel cell or storage battery whose voltage cannot be adjusted, and performs effective, uncontrolled power control of its output. This is done by borrowing two groups of inverters that do not have the ability to adjust the output voltage P1 on their own, and by controlling each inverter in phase 4+' (phase control), the voltage M
Double adjustment device? This is because by adjusting the magnitude and phase of the I11 voltage without using t, it is possible to control the effective output and relaxation box force.

[7, η next technology and 1 point between them] e:”;, 'r l>+ is a
A block diagram showing the general structure of the invert system used in the XR11'8 or Figure 2 is a block diagram based on Figure 1. FIG. 3A is a vector diagram showing the voltage and current vectors of each part, and FIG. 3A is a vector)/L-diagram similar to FIG. 3, showing the system voltage as an 11·8Q1 axis. In Figure 6311, 1 is a constant voltage power source 2 is a reactor, 3 is a smoothing capacitor, and 4 is an A
5 is an 8-group inverter, 6 is an output transformer, 7 is a series reactor, and 8 is a power system. In addition, in Fig. 2, ll is the A group inverter model, 12 is the 8
The group inverter model, 13 is the power system model, and v
s is the system voltage, VA is the A group impark voltage, VB is the 8 group inverter voltage, and ■i is the inverter composite output voltage.

As is clear from FIG. 1, the output voltage of the current power supply 1 is applied to two voltage type self-excited inverters 4 and 5 via DC smoothing circuits 2 and 3. These inverters 4.5 are each phase-controlled and produce an output voltage whose phase is determined by the kneading and whose magnitude corresponds to the input DC voltage. Then, these output 11° C. pressures are vectorially combined by the output transformer 6, and this can be supplied to the power system via the series reactor 7. It should be noted that if this -f member per system is expressed as a block model, then tδ2112j
Like <7. The relationship between the nail, the rod pressure in that case, and the current vector is ri's 3! ”:l:l: Taha Pa 3 A Figure (7) <6゜Output active and reactive power control in an inverter system consisting of two voltage-type self-excited inverters whose phase is controlled in this way has conventionally been performed as follows: The central phase ψ0 of the output voltages of the two inverters (see Figure 3 or Figure 3A) is made to correspond to the active power P, and the opening angle Δψ is made to correspond to the reactive power Q, and a feedback loop is created based on this. Note that this is equivalent to the control method of an inverter system that controls the reactive power Q by the chopper's conduction rate and the active power P by the inverter phase in a system that combines a chopper and an inverter. , Jugo its effective power.

The reactive power control loop is not a non-interfering control system, but forms a control system in which Q interferes with each other and settles to the 5th value. Therefore, it is not possible to control P and Q individually, and as a result, when the set value of P is changed, the output active power changes and Q also temporarily moves back significantly. This is because as the capacity of inverters operated in grid-connected mode increases,
It also became a prisoner of disturbances to the power system. Further, in a system where P and Q interfere with each other and vibrate in this way, there is a problem in that the response rate of the control system cannot be increased very much from the standpoint of keeping the system stable.

Here, the reason why active power P and reactive power Q cannot be divided independently is explained below based on grid voltage VS.
The voltages of FIG. 3A are shown in a complex coordinate system where .

1) Detailed explanation will be given with reference to the first flow vector diagram.

As is clear from FIG. 3A, the system voltage VS % can be expressed as follows. Note that the mark (・) indicates that it is a vector quantity.〇■8-vS
・・・・・・ (1) VH= Vd+
jV9 song... (2) 1 = Ict + J Iq ・- Song (3) - Same, the system flow actance drop is, when the series reactor resistance actance is X, jXI = VH-Vs ・=-
It is expressed as (4). Therefore, (1) above?
From equations (2) and (4), I=(VIVs)/jX.

By the way, the effective power P supplied from the inverter to J[
1 Ineffective Tortoise Force Q is P=VBId ・-・・・・
(8) Q'''Vs (Iq) (However, the companion is positive.

)...(9) can be expressed as (8) # (9) and the above (6).

(Substituting the formula 7, we get is obtained.

- Twine inverter composite voltage Uj force voltage V7t'i, Ill h voltage Vp-p Vn of the two inverters is the atmospheric pressure obtained by vector synthesis using an output transformer. Therefore, it is assumed that the phases of inverters A and H are respectively ψA,
If ψB and input device flow regulation voltage are different from Ed, then these voltages VΔ, V (( can be expressed as in the following formula 0 VA = KIEd (cos #pA + j sin ψA)
-------・(+21Vn-Kx sd
(CO3'l'B+jsin9'B)
=-・ (131 5 Therefore, its composite force, pressure Vi, is
+cosψB )+j(sinψA-)sinψn)1 ψA-ψB ψA+ψB -2aKIEdcos , -, -, ------(cos
2-, -=Kg(IcosΔψ(part ψ0+jsin
ψ0)・・・−・(14) In addition, in formulas 04-04), Kl is a constant,
As shown in A121, they correspond to the central angle and 1jii angle of VA, v, , respectively. Also, since the above equation (14) is equal to the equation (2), Vd-
1gfldcO3Δ9'CO59'G
−−−−−−(15!Vq = K
JNdcos Δψsinψo・・・・・・(I (expressed as 1゛1. Therefore, 0, (lfi1 formula E
Substituting into the equation (1(1), 01), S )””,・KEdcosΔψ5in(P.

], and 4(su, Δψ, ψ0 and P, (2) are combined.

From this formula, the outputs of inverters A and B are '11'j, IJ
:, VA.

Both the center phase ψ0 and the sharpening angle Δψ of VIS are B'J d of P and Q, and therefore ψ0. which represents the phase of the output voltage. Δψ, which represents the magnitude of the output voltage, is simply P.

(It can be seen that even if it is controlled by making l to 1 + t, P and Q are not a non-interfering system.

[Purpose of the invention]

This invention was made by focusing on two points, and the control of active power and reactive power is performed by influencing each other.
: t, by not matching, that is, by non-interference, the effective and reactive power it+:,l with excellent transient response.
The purpose is to provide an E+ system.

[Key points of the invention]

The main point of this invention is that two
Effectiveness of an inverter system consisting of a type white-excited inverter,
Is there a system that corresponds one-to-one to each of active power, L, and reactive power to the platform that controls reactive power? Xit'hk (
c, osΔψ・sinψ0. CLISΔψ”CJ)Jo
o), calculate the firing phase ψA, ψB of each inverter by vector calculation of El and If control St, and control the phase of the inverter using the firing phase ψA t 9'B to calculate the active power. ii[effect'/2. The point is that power can be divided by 1 without interference.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.The fourth figure is a block diagram showing five practical examples of the present invention.

In the figure, 21 is a DC voltage detector, 22 is a transformer, 23 is a current transformer, 24 is an active/reactive power detector, 25 is a 3-phase/2-phase converter, 26.38 is a vector calculator, 31
is an active power setting device, 32 is a reactive decoy, a force setting device, 33 is an acceleration/deceleration calculator, 34 is an active power t/74 node, 35 is a reactive power detector, 36 is a current regulator, 37 is a t&qJ ii
39 is an arc cosine calculator, 40 is a pulse generator, and 1 to 8 are the same as in FIG.

Based on the respective ffQ constant values of active power P and pyroelectric power set in the setters 31 and 32, a predetermined calculation is performed in an acceleration/deceleration calculator 33 having a so-called soft start function, and the target value P* is determined.

Ql is derived. These target values 17. Q* is the grid voltage 98 detected via the transformer 22 and the current transformer 23
From the inverter output current detected via detector 2
After being compared with each detected value (actual value) of P and Q detected at step 4, active power regulator 34. The output current is input to the reactive power regulator 35, and the output current is the dill.

Respective scale values Id* and Iq* of the q-axis component are obtained. Note 1
This calculation is clearly explained by referring to equations (8) and (9) above. Under the condition that the grid voltage Vs is constant, P and Q are proportional to d and I, respectively (linear relationship(
This shows that it has validity.

On the other hand, each (AC D
ir', fl) are supplied via a 3-phase/2-phase converter 25 to a known vector computing unit 26 consisting of a mechanical amplifier (operational amplifier), a multiplier, a divider, etc. It is converted into DC iId, Iq and output as detection Wi. These detection values Id, Iq4; 'current target value 1d*・■q which is each output value of J active power regulator 34 and reactive power regulator 35 * and is given to the current cylinder r4fj unit 36, but as is clear from the previous equations (6) and <7), ■d and ■9 and I9 and Vd are in a proportional (linear) relationship, respectively. Therefore, ■d, Vq can be obtained from the output of the current regulator 36. Then, ■0) Vd,
Vq HaQ5) p uQ formula shows h le, i':
) Ni, V (1 = KE, 1 cosΔψcosψOV
q = KEdcosΔII) sin ψ0, so the divider 37 divides Vd r Vq obtained as described above.
When divided by KEd, the outputs are cosΔrp cos tp6, respectively.
・--Q! I) will be introduced. Furthermore, these signals (CO3Δψ・CO39)O, CO3Δψ・sl
[lψ0) is given to a known vector calculator 38, where it is separated into COSΔψ and ωSψ0, and then arc c
Δψ and ψ0 are determined by the os (cos) calculator 39. Since Δψ and ψ0 are, by adding and subtracting them, the firing phase ψAgψB of the inverters A and B is obtained, which is converted into a firing pulse by the pulse generator 40. The ignition pulses obtained in this way are respectively applied to inverter A (4
), are supplied to inverter B (5), and a control system in which P and Q do not interfere with each other is constructed.

other FIG. 5 is a partial configuration diagram showing an embodiment of the present invention.

In the explanation above, it has been assumed that the system voltage Vs does not fluctuate, but when vS fluctuates, the following procedure is performed. In other words, the relationship between P, Q and Vs is as shown above (
8) From equation (9), P=Vsfd
-・・−・(8)(9-\'s(Iq)
...... Since it is expressed as (9), the active power regulator 34. The output of the reactive power regulator 35 should not be treated as \Id*, ■, *, but should be divided by Vs before calculating these values. Example 6] 1 is shown in the same figure (A). That is, in this example, the active and reactive power regulators 34.35
By providing a divider 37 for dividing the output of Vs by Vs, it is possible to avoid being affected by fluctuations in Vs.

On the contrary, if the change in the DC voltage Ed is minute or slow over time, the divider 37 in FIG. 4 is omitted and the structure is configured as shown in FIG. 5(B). and keep the output of the current regulator 36 as it is 1CO3Δψ・sinψo,
It may be handled as CO5ΔψCOSψ0.

Furthermore, as a simplified configuration, the current regulator is also omitted as shown in FIG. 5(C), and the active and reactive power regulators 34, 35
The output of \ωSΔψ・sin! 'opCO3Δψ
- It may be used as COSψ0. The size was
In this case, it may be necessary to provide a current limiter.

〔Effect of the invention〕

As described above, according to the present invention, fil (cosΔ
After calculating ψ・5in91IO, coS71ψ・ωS9'o) and separating it into Δψ and ψ0 using a vector calculator and a cos calculator, add and subtract these to obtain the firing phases ψA and ψB of inverters A and B. By obtaining P
-Q Since we are trying to realize a non-interference system, there is no need to give unnecessary disturbances to the system, which brings the advantage of realizing a stable system with quick response.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the general configuration of an inverter system consisting of two groups of inverters, Fig. 2 is a block diagram showing a modular version of Fig. Figure 3A is a vector diagram showing the voltage and current at each part in the figure. Figure 3A is a vector diagram similar to Figure 3, showing the system voltage as the reference axis. Figure 4 is a configuration diagram showing an embodiment of this generator. FIG. 5 is a partial configuration diagram showing another embodiment of the present invention. Symbol explanation■・・・DC power supply, 2・・・Smoothing reactor, 3・・・Smoothing capacitor, 4,5・・・・・・
・Inverter, 6゜22...Transformer, 7...
...Series reactor, 8...Power system, 11
...A group inverter model, 12...
8 group inverter model, 13...Power system model, 21...DC voltage detector, :23...
... Change 1) 1 position) Soup, 24 ...... If effect, reactive power detection domain, 25 ...... 3-phase / 2-phase change device, 26
．． 38...Vector performance 1> vessel 13...
・Active power regulator, 32... Power effect 117
．． Power setting device, 33... Acceleration/deceleration calculator, 34...
...Active power J,) 1 clause silent, 35...Reactive power regulator, 36...Bending current adjustment, 37.37...
...Divider, 39...,'+rc cos group Cα calculator, 40...Pulse generator agent Patent attorney Akira Namiki Ooyo + II (Patent attorney Kiyoshi Matsu) Figure 1 Figure 2 Figure f Figure 3

Claims (1)

[Claims] A system that controls the active and reactive power of an inverter system consisting of two voltage-type self-excited inverters connected to a power grid, and the deviation between each target value of active power and reactive power and its field value. From this, calculate the current (or voltage) component of the inverter output current (or voltage) that is in phase with the system πf1 pressure and the current (or voltage) component that is 90 degrees out of phase with this, and calculate one pair with each of the active and reactive power. 1, and firing angle calculation means that calculates the firing phase angle of each inverter from each control jump. An effective and reactive power control system characterized by performing phase control.