JPH01186166A - Power distribution control device - Google Patents

Abstract

PURPOSE:To control loaded power constantly at all times, by comparing the affective power command value of an FC (standstill type frequency conversion) device with the effective power value and by adding the deviation to the phase of a reference frequency of the FC device obtained from the output voltage of an M-G (rotation type frequency conversion) device. CONSTITUTION:Through a three-phase line 2, an M-G device 3 and an FC device 4 are connected in parallel to a three-phase power source 1, while a load terminal is connected to an output terminal 4 of the FC device 4 through a switch 5 and the other load terminal is connected to the output terminal 4 of the FC device 4 through an AC reactor 6 to supply the current to a load 7. A control circuit is composed of power detectors 11-12, an effective power setter 14, shorting switches 15-16 at the input and output terminals of above setters 13-14, control compensation circuits 17-18, a PLL circuit 19, etc. The reactive power command value of the FC device 4 is thereby compared with the reactive power value and the deviation is added to the voltagecommand value of the FC device 4, which is then given as a crest value command of the output voltage of the FC device 4.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a rotary frequency converter f (hereinafter referred to as MG device) and a static frequency converter (hereinafter referred to as FC device). (abbreviated)) is operated in parallel to supply power to the load, and in particular, depending on the power consumed by the load, the FC
The present invention relates to a power distribution control device that distributes active and reactive power to be borne by devices.

(Prior art) Conventionally, when increasing the capacity of an M-G device, an M-G device of the same capacity is used.
A G device was added and parallel operation was performed.

However, in recent years, when increasing the capacity of M-G equipment,
There is a technique to do this by running the G device and the FC device in parallel. For example, Japanese Patent Application Laid-Open No. 62-28815 discloses a technique regarding the parallel operation of the MG device and the current-controlled FC device. ing.

This technology operates an FC device that operates under current control in parallel with an MG device, with the MG device supplying only active power and the FC device supplying power including reactive power required by the load. This is a logical way to improve the operating efficiency of the MG device and improve the response to load fluctuations.

(Problems to be Solved by the Invention) However, the above conventional technology has the following points of inquiry.

■ It is difficult to operate independently with FC @ installation.

■ It is difficult to arbitrarily allocate the active power and reactive power of the load.

Therefore, an object of the present invention is to arbitrarily allocate the active power and reactive power of the load to the FC device, and to arbitrarily divide the load power between the M-G device and the FC device so that the load can be operated independently by the FC device.
Provided is a power distribution control device that can allocate power to C devices.

[Structure of the invention]

(Means for Solving the Problem) Therefore, in order to achieve the above object, the present invention provides F.
Power distribution control comprising active power control means for controlling the active power by controlling the phase of the output voltage of the C device, and reactive power control means for controlling the reactive power by controlling the peak value of the output voltage. Provide equipment.

(Function) In the device configured in this way, the active power command value of the FC device obtained from the active power value of the load is compared with the active power value of the FC device, and the deviation is calculated as the output voltage of the MG device. By adding it to the phase of the reference frequency of the FC device obtained from the above, the active power borne by the FC device is controlled. F
Control the reactive power borne by the C device. Through these active power control and reactive power control, the power borne by the MG device and the FC device is always controlled to be constant, regardless of the magnitude of the load power.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, an M-G device 3 and an FC device 4 are connected in parallel to a three-phase power supply 1 via a three-phase electric line 2, and a load terminal of the M-G device 3 is connected via a switch 5. Connected to the output terminal.

The other end is connected to the output terminal 4 of the FC device 4 via the AC reactor 6, and supplies frequency-converted AC power to the load 7.

Note that as the FC device 4, a circulating current type cycloconverter capable of controlling input reactive power is used.

As a control circuit, the active current PL and reactive current Q of the load 7
power detector 11 for detecting L; power detector 12 for detecting active power Pc and reactive power Qc of FC device M4; load 7;
an active power setting device 13 that receives as input the active power pL of the load IO; a reactive power setting device 14 that receives the reactive power QL of the load IO as the input;
A switch 15.16 that shorts the input and output terminals of the active and reactive power setting device 13.14, and a control compensation circuit 17.1g, PL.
L circuit 19, multiplier 20, FC@equipment voltage command circuit 2
1, comparators 22 and 23, and an adder 24.

Next, the control operation will be explained.

In this case, switch 5 is closed and switches 15, 16 are opened for parallel operation.

The active power value PL detected by the power detector 11 of the load 7 is input to the active power setting device 13, and the setting device 13 is an FC device! Command value Pc' of active power Pc shared by i4
Output. Command value Pc't±compared with active power detection value Pc of FC device 4 by comparator 22, and its deviation ε.

is input to the control compensation circuit 17.

In that case, the control compensation circuit 17 is simply an amplifier, and if the gain is K, the output value is Δθ=K·ε.

and is input to the PLL circuit 19. This PLL circuit 1
Reference numeral 9 outputs a three-phase unit sine wave e0υ, ecv, ecv.
(Patent Registration No. 13)
14945).

ecυ= sin (ωt+Δθ) ■51
eV = sin (ωt-2π/3+Δθ) ■
ecy=sin(ωt+2π/3+Δθ) ■This three-phase unit sine wave ecυe a 6 V te CI#
is input to the multiplier 2o.

On the other hand, the reactive power value QL detected by the power detector 11
is input to the reactive power setter 14, and outputs a command value QC14 of the reactive power Qc shared by the FC device 4. Command value Qc
X is FCV&! by comparator 23. ! 4 reactive power detection value Q
c, and in the adder 24 via the control compensation circuit 18,
It is added to the voltage command value VL)II. The added value is FC
It is input to the multiplier 20 as the voltage peak value command Vc of the device 4.

The multiplier 20 generates a three-phase unit sine wave e0υe6eV*6ev
and the peak value command Vc', and output the voltage command VeU'*VeV'*6em' for the FC device 4.

Vcu'=Vc 5in(ωt+Δθ) (
to) ecv = Vc ain (ωt-2π/3+Δθ)
■ec-=Vc 5in(ωt+'2c/3+Δθ
) 0 Thus, the output voltage Vc of the FC device 4 is controlled.

Next, an example of a specific configuration of the FC device 4 is shown in FIG. 2.

The FC device 4 shown in Fig. 2 is a voltage-controlled circulating current type cycloconverter, which can make the output frequency higher than the input frequency, and can control the input reactive power by providing a phase advance capacitor at the receiving end. ing.

In FIG. 2, 30 is a three-phase electric line, 31 is a phase advancing capacitor, 32 is one phase of a cycloconverter, and 33 is a load (one phase).

The main circuit of the cycloconverter 32 for one phase consists of a power transformer 34, a positive group converter 35, a negative group converter 36, a DC reactor 37.39, and a converter 35.3.
6 is insulated by a power transformer 34.

The other two phases have similar configurations.

In the load voltage control of the cycloconverter 32, depending on the deviation between the voltage command value vcu' and the actual load voltage VCυ,
Positive group voltage VP of positive group converter 35 and negative group converter 3
Negative group converter 3
The phase signal to 6 is inverted and given.

As a result, the average voltage becomes the load voltage and is controlled regardless of the circulating current factor 0.

Further, the circulating current control controls the difference between the positive group voltage Vp of the positive group converter 35 and the negative group voltage VN of the negative group converter 36 without changing their average voltage.

That is, a phase signal is given so that VP is increased according to the deviation between the circulating current command Io' and the actual circulating current Io obtained by calculation, and at the same time, VN is decreased by the same amount.

Furthermore, in reactive power control, a current detector 39 and a voltage detector 40 are provided at the receiving end, and a reactive power calculation circuit 41 detects input reactive power Q, and compares it with a set reactive power command value t)I. , a circulating current command knee is given according to the deviation E1.

Furthermore, the control compensation circuit 42 includes an integral element to suppress the occurrence of steady-state deviation.

Therefore, when the reactive power command Q% is set to zero, the leading reactive power of the phase leading capacitor 31 and the cycloconverter 32
The circulating current I
o is controlled, and the input fundamental wave power factor at the receiving end becomes 1.

Next, the operation of the embodiment shown in FIG. 1 will be explained in more detail using FIGS. 3 and 4.

FIG. 3 shows the voltage and current of each part when the MC device 50 and the FC device 51 are operated in parallel, and the load 52 is given by Re + SLe.

Further, as a parallel operation condition, it is assumed that the output voltage VL (=VG) of the MC device 50 is controlled to be constant by generator field current control.

When parallel operation is performed under the above conditions, the following relationship holds true between voltage and current.

Ve= (Re+5-Le)It ■
vx=S-Lc・1cc ■Vc
=VL+Vx (9)IL=I
OC+IQ (10) where v
L: Load voltage Vc: Output voltage of the FC device Io: Output current of the MC device Icc=IcR+I (Hx: Output current I of the FC device
Blind 4: Load current Figure 4 (A), (B), and (C) are the above ■~(1
0) is an example of a vector diagram of voltage and current in each city based on formula.

FIG. 4(A) is a vector diagram of voltage and current when the MC device and the FC device bear the active power P and reactive power Q of the load equally.

The load current I+4 is the sum of the output current of the MC device and the output current ICI of the FC device, and has a phase delay θ□ with respect to the load voltage V.

In this case, active current Icp = IGP, reactive current I(:
Q = I (Ilil, the total is Ip = I
cp + Iap and IQ = Ice + Iae.

On the other hand, the output voltage Vc of the FC device is 90% lower than the output current ICL.
It is the sum of the phase lead and the voltage Vx of the accelerator Lc, and Vc has a phase lead by θ2 from V.

(B) is determined by the active power setting device 13 shown in FIG.
FIG. 7 is a voltage and current vector diagram in a steady state when only the active power borne by the FC device is increased.

The phase θ2 of the output voltage Vc of the FC device further advances (A
), the effective current Icp increases and the effective current IGP of the M-G device decreases.

As a result, the load current IL is the sum of ICL and IOL,
The size and phase remain unchanged.

In this case, in order to keep the reactive current xco constant, the reactive power control circuit works to increase the output voltage Vc, and the I
CQ'' IGQ. (C) is a voltage-current vector diagram in a steady state when only the reactive voltage borne by the FCM device is increased by the reactive power setter 14 shown in FIG.

The peak value of the output voltage Vc becomes larger (compared to A),
Reactive current ICQ increases and IOQ decreases.

As a result, the load current II, is IC! , and IGL, and as in CB), 1. . The magnitude and phase of are unchanged.

In this case, in order to keep the active current ICP of the FC device constant, the active power control circuit operates to reduce phase 02, resulting in ICr'''IOP.

As mentioned above, the magnitude of the output voltage of the FC device and the phase 02
By controlling the above, load power can be arbitrarily distributed to the MG device and the FC device.

Next, independent operation will be explained.

In FIG. 1, the FC device 4 can be operated independently by opening the switch 6 and closing the switches 15 and 16 of the control circuit.

In this case, the deviation εC and (Q become zero, and the load voltage vL is set to
given from.

〔Effect of the invention〕

As explained above, the present invention provides the following effects.

ωFC1i! Since the magnitude and phase of the output voltage of i[ can be controlled, it is easy to arbitrarily share the active power and reactive power of the load.

■ Even when the MG device is stopped for maintenance inspection, power can be supplied to the load by operating the FC device independently.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing one embodiment of the present invention, Fig. 2 is a circuit configuration diagram of the FC device used in Fig. 1, and Fig. 3 is a main circuit block diagram for explaining the present invention in detail. , FIG. 4 is a voltage-current vector diagram for explaining the present invention in detail. 3.50...Rotary frequency converter (MG device) 4
．． 32.51...Static frequency converter (FC device)
? , 33.52... Load 11, 12... Power detector 13... Active power setting device 14... Reactive power setting device 15.16... Sui, Tsuchi 17.1
8...Control compensation circuit 19...PLL circuit 2
0... Multiplier 21... Voltage command circuit 22.2
3... Comparator 24... Adder Agent Patent attorney Rule Ken Chika Yudo Ken Daishimaru Figure 3

Claims (1)

[Claims] In a power supply system that supplies power at a predetermined frequency to a load by operating a rotary frequency converter and a stationary frequency converter individually or in parallel, the static frequency is adjusted according to the active power and reactive power of the load. comprising active power control means for controlling the active power by controlling the phase of the output voltage of the conversion device; and reactive power control means for controlling the reactive power by controlling the peak value of the output voltage; A power distribution control device that arbitrarily controls the distribution of active power and reactive power of the load.