JPS6279513A - Control method and device for electric power converter - Google Patents

Abstract

PURPOSE:To prevent the rush of a direct current output voltage by supplying to plural AC to DC converters so that the size relation of respective control delay angles supplied to plural AC to DC converters can not be reversed. CONSTITUTION:A valid invalid electric power control circuit 12 calculates and outputs control delaying angles alpha1 and alpha2 of AC to DC converters 4 and 5 with a valid electric power command value Pr and an invalid electric power command value Qr supplied from the high-order system control device as control inputs. The control delaying angles alpha1 and alpha2 are used as control inputs, syn chronized with an alternating current voltage Va obtained through an alternating current voltage detecting circuit 9, and an ignition pulse g1 to operate the AC to DC converter 4 by the control delaying angle alpha1 is generated and an ignition pulse g2 to operate the AC to DC converter 5 by the control delaying angle alpha2 is generated by a phase control circuit 13, respectively. Through a gate circuit 14, ignition pulses g1 and g2 are respectively supplied to the AC to DC converters 4 and 5 to be controlled.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control method and device for a power conversion device, and in particular, a method for independently and asymmetrically controlling each control delay angle of a plurality of AC/DC converters connected in series. The present invention relates to a control method and device for a power conversion device suitable for controlling a power conversion device.

[Background of the invention]

Connecting multiple AC/DC converters in series can reduce reactive power consumption, and by independently and appropriately controlling the control delay angle of each AC/DC converter connected in series, active power and reactive power can be reduced. It is known that power can be controlled simultaneously.

Regarding this kind of simultaneous control of active and reactive power,
In the Proceedings of the 7th National Conference of the Institute of Electrical Engineers of Japan, Mr. Ise et al. discusses a method for simultaneous active and reactive power control of superconducting energy storage devices. As a document, the patent application 1983
There is No.-11839.

To control active power and reactive power simultaneously, the control delay angles of multiple AC/DC converters are controlled separately.

That is, the plurality of AC/DC converters are not controlled with the same control delay angle, but are controlled asymmetrically with each control delay angle being made independent.

In other words, when controlling active and reactive power at the same time, the control delay angle is calculated and determined so that the actual active power and reactive power become the command values according to each command value of active and reactive power, respectively. supply to the AC/DC converter.

At this time, if the command value of active power or reactive power changes in a sinusoidal manner, especially if the command value of active power changes from positive to negative or from negative to positive, the calculated control delay angle α is its lower limit. Value α□. and the upper limit value αm□, and the output voltage of each AC/DC converter also changes accordingly.

In particular, when the active power command value changes from positive to negative or from negative to positive, the control delay angle α changes to the rectifier operating region (α<90
°) to the inverse converter operating region (α)90') or vice versa.

When the rectifier operating region changes to the inverter operating region due to a change in the control delay angle α, the output voltage of the AC/DC converter shifts from a positive voltage to a negative voltage along the transformer power supply voltage waveform. do.

On the other hand, when changing from the inverter operating region to the rectifier operating region, the output voltage abruptly changes from a negative voltage to a positive voltage depending on the control delay angle.

Therefore, for example, the magnitude of the control delay angle of two AC/DC converters connected in series changes from the rectifier operating region to the inverter operating region for one, and from the inverter operating region to the rectifier operating region for the other. In other words, when the magnitude relationship of each control delay angle is reversed, the output voltage of each AC/DC converter shifts from a positive voltage to a negative voltage or from a negative voltage to a positive voltage at the time of the change. However, as mentioned above, there is a time difference.

Therefore, there is a problem in that the DC output voltage of two AC/DC converters connected in series causes a steep voltage jump at the time of change.

Although the case where two AC/DC converters are connected in series has been described above, a similar phenomenon occurs when a plurality of AC/DC converters are connected in series, resulting in a problem.

[Purpose of the invention]

An object of the present invention is to reduce the time difference between the output voltage waveforms of each AC/DC converter even when the control delay angles for a plurality of AC/DC converters connected in series change greatly and the magnitude relationship of the control delay angles is reversed. An object of the present invention is to provide a control method and device for a power conversion device that prevents a jump in DC output voltage from occurring.

[Summary of the invention]

The present invention provides a method for controlling active power and reactive power using individual control delay angles by connecting a plurality of AC/DC converters in series, that is, when controlling the active power and reactive power asymmetrically. control delay angles of the plurality of AC/DC converters, which are calculated based on the deviation from the DC voltage and the no-load DC voltage and the DC load current, are supplied to the plurality of AC/DC converters according to the magnitude relationship of their values. The feature is that the DC output voltage is prevented from rising by supplying it to the plurality of AC/DC converters so that the magnitude relationship of each control delay angle is not reversed.

[Embodiments of the invention]

An embodiment in which the present invention is applied to an energy storage device using a coil connected in series with two AC/DC converters will be described. In this embodiment, each AC/DC converter is controlled asymmetrically.

FIG. 1 shows the overall configuration of an energy storage device using coils. The main circuit includes an AC/DC converter 4゜5 connected to the AC system 1 via converter transformers 2 and 3, and an AC/DC converter 4.
．． The energy storage superconducting coil 6 serving as a load of 5 is connected in a loop.

The control circuit includes an electric quadrature transducer 11, an active/reactive power control circuit 129, a phase control circuit 13, a gate circuit 14, and the like.

The voltage and current of the AC system 1 are detected by an AC voltage detection circuit 7 and an AC current detection circuit 8, respectively, and taken into the electric card 2 transducer 11. The electric quadrature transducer 11 calculates active power P and reactive power Q flowing into the device based on the detected voltage and current of the AC system 1.

The active power P and reactive power Q1, the DC current Id detected by the DC current detector 10, and the no-load DC voltage b0 per AC/DC converter proportional to the amplitude of the AC voltage (no-load DC voltage detection circuit 15) ) is taken into the active/reactive power control circuit 12.

In the active/reactive power control circuit 12, the active power command value Pr and the reactive power command value Q given from the upper system control device are
Control delay angle α of AC/DC converter 4°5 with r as control input
8. α, is calculated and output.

This control delay angle α1. ignition pulse g which uses α as a control input and operates the AC/DC converter 4 at a control delay angle α1 in synchronization with the AC voltage Va obtained via the AC voltage detection circuit 9.
1, and the ignition pulse g! that operates the AC/DC converter 5 with a control delay angle α! is generated by the phase control circuit 13.

Then, via the gate circuit 14, the ignition pulse gl
+g! are supplied to AC/DC converters 4.5 to control them.

In FIG. 1, the commutation reactance of converter transformers 2 and 3 is taken as the no-load DC voltage of AC/DC converters 4 and 5, respectively. Expressed as follows, the relationship between the phase angle θ1 of the fundamental wave component of the alternating current flowing through the converter transformer 2 and the control delay angle α1 of the AC/DC converter 4 is as follows.

Similarly, the phase angle θ of the fundamental wave component of the alternating current flowing through the converter transformer 3 and the control delay angle α of the AC/DC converter 50! The relationship with is as follows.

Using the phase angle θ sound defined above, the active power PI+reactive power Q1 flowing into the AC/DC converter 4 can be expressed by the following equations (3) and (4).

Pl = Id-Ed(1cosθ1...
・・・・・・・・・(3) Q, = Id−Ed6
slnθ1 (4) Similarly, active power Pt + reactive power Q flowing into the AC/DC converter 5
, can be expressed by the following equations (5) and (6).

P goose = Id-Ed6 eos 02 ・・・・・・
・・・・・・・・・(5)Q! = Id-Ed6s
inθ2 ・・・・・・・・・・・・・・・(6)(3
), (4), (5), and (6), the first
The active power P and reactive power Q flowing into the energy storage device shown in the figure are expressed by the following equations (7) and (8).

P ”' p, 10P@” Id ”Ed6 (e08θ
Soup coa o@) ・= −(7)Q ” Q++Qt
= Id−Edo(sinθ1+sinθt) −−(
8) The following equation is obtained from equations (1), (2), (7), and (8).

cowθ1+cosθ,=□・・・・・・・・・・・・
・(9)Id-Ed.

Xc-Id (11=0011-' (QO8θI+)
-・Town---(u)πEd.

Ed.

Therefore, the active power command value Pr, the reactive power command value Q
When r is given, by setting P=Pr and Q=Qr, from the above equation (9) 1 (10), coalll,
Come wealth is found. Nine, this eelθ1. coa
By substituting ll into equations (11) and (12), the control delay angle α1. α, can be found. Nika＼
If instead, each linear converter is fixedly supplied and controlled, the control delay angle α1 . When the magnitude relationship of α is reversed, a problem arises when the DC output voltage jumps at the time of reversal of the 1-fit control delay angle as described above.

Focusing on this point, in this embodiment, the active/reactive power control circuit 12 is configured as shown in FIG. 2.

In FIG. 2, 121 is a constant active/constant reactive power control circuit section, 122 is a control delay angle calculation section, and 123 is each calculated control delay angle α. ,α,. This is a comparison output circuit unit that compares the magnitudes of , determines the output light based on the order of magnitude, and outputs the control delay angles αI, α, to the phase control circuit 13.

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. In FIG. 3, (&) is the DC output voltage, (b) is the AC/DC converter output voltage, and (C) is a time chart of the control delay angle.

Active power command value Pr from the upper system control device.

The constant active/constant reactive power control circuit unit 121 uses the reactive power command value Qr as a control input and uses the deviation of the active power P and reactive power Q that actually flow into the device from the control input.
Then, the internal setting value P is set so that the active power P1 and the reactive power Q match the command values Pr and Qr of active power and reactive power, respectively. Determine t Q6.

Next, this internal setting value P. Based on rQ(1, control delay angle signals α, ., α, . are calculated in the control delay angle calculation unit 122 using the no-load DC voltage Ed0 and the DC current Id, and output to the comparison output circuit unit 123. do.

The comparison output unit 123 compares the control delay angle signal αto + α, 00 from the control delay angle calculation unit 122,
Always use the larger value tilll 111 delay angle α11,
The smaller value is defined as α, and the phase control circuit 13 is given a control delay angle α1. Output as α2.

That is, the control delay angle signal is α1o≧α. If α1=
Define α1゜, α2-α2゜, and conversely α,. <In the case of α2o, α1=αtQ +α2=α. and change the control delay angle signal.

In the phase control circuit 13, the AC/DC converter 4 is controlled at a control delay angle α.
A firing pulse g1 that operates the AC/DC converter 5 is generated at a control delay angle α, and a firing pulse g*'Jk that operates the AC/DC converter 5.

FIG. 5 shows a block diagram of a specific configuration example of the comparison output section 123. In this example, the control delay angle calculation unit 122 calculates,
In Fig. 5, which shows the case where the control delay angle signals α1°, α, 0 to be output are analog quantities and there are two AC/DC converters, the same symbols are given to those having the same functions as in Fig. 2. It is.

Also, 60-63 are arithmetic multipliers, 64-69°72-
78.81 is resistance, ? 0,71,79.80 are diodes.

An operational circuit consisting of an operational amplifier 60.61, resistors 64 to 69.72, and a diode 70.71 is an operational amplifier 60.61.
Control delay angle signal α1°, α, which is an input of 0.61. This circuit outputs the larger of the nine values to the phase control circuit 131 as the control delay angle α1.

That is, among the two control delay angle signals, α1° is α. Assuming that the output of the operational amplifier 60 is higher than the output of the operational amplifier 61, the diode 71 connected to the output of the operational amplifier 6e becomes reverse biased and is cut off. Ru.

As a result, the output of the operational amplifier 60 is output via the diode 70 as the control delay angle α1.

In addition, the operational circuit consisting of the operational amplifier 62.63, the resistors 73 to 78°81, and the diode 79.80 receives the control delay angle signal α101α at the input of the operational amplifier 62.63.
, 0 is output to the phase control circuit 132 as the control delay angle α.

As mentioned above, the 9th one of the two control delay angle signals, α1°, is α. Assuming that the operational amplifier 6 is larger than
Since the output of No. 2 has a higher level than that of the operational amplifier 63, by appropriately setting the voltage Vcc, the diode 79 connected to the output of the operational amplifier 62 becomes reverse biased and is cut off. It can be done.

As a result, the output of the operator 63 is outputted as the control delay angle α via the diode 80.

As a result, the phase control circuit 131 generates a firing pulse g1 that operates the AC/DC converter 4 with a control delay angle α1, and on the other hand, a firing pulse g! that operates the AC/DC converter 5 with a control delay angle α! is generated by the phase control circuit 132 and supplied to each AC/DC converter 4.5 via the gate circuit 14 (FIG. 1).

With the configuration as shown in FIG. 5, it is possible to change and define the output light depending on the magnitude of the control delay angle, and it is possible to obtain the control delay angle control according to the present invention described above.

FIG. 3 shows waveforms of various parts when controlled by the present invention. Third
As shown in Figure (C), the control delay angle α1 is always a larger value than α, and these ? [Since the AC/DC converter 4.5 is controlled by the delay angle of Ilj,
), no voltage jump occurs in the DC output voltage waveform.

For comparison, FIG. 4 shows, for example, a control delay angle signal α, without implementing the present invention. to the AC/DC converter 4, and the control delay angle signal α,. is the waveform of each part when the control delay angle signal obtained by the control delay angle calculation unit 122 is fixedly supplied to each AC/DC converter for control, regardless of the magnitude relationship, such as to the AC/DC converter 5. show. The waveforms in the same figure (,) ~ (
C) correspond to the waveforms (,) to (,) in FIG. 3, respectively.

As shown in FIG. 4(c), the control delay angle α1. At the timing when the magnitude relationship of α is reversed, a rising portion occurs in the DC voltage waveform as shown in FIG. 4(a).

FIG. 6 shows another embodiment of the invention. Figure 6 shows active/reactive power control circuit 1 when n AC/DC converters are connected in series.
The configuration of No. 2 is shown below. In Figure $6, the same functions as Figure 2
Components that operate are given the same reference numerals.

FIG. 5 differs from FIG. 2 in the following points.

First of all, the control delay angle calculation unit 122 calculates the control delay angle signal αIQ lα! for n units. . ,α,. ,・・・・・・
shaft.

is calculated and output to the comparison output section 123.

Second, the comparison output section 123 outputs these control delay angle signals α101α. ,α,. ,...,α. . Compare the values of α1≧α, ≧α, ≧・・・・・・・・・≧α.

The Mayuki control delay angle signal α, so that.・・・・・・
shaft.

are exchanged and output to the phase control circuit 13. The phase control circuit 13 generates a firing pulse gt+g! that operates each AC/DC converter. +gj+...+gn is generated and supplied to each AC/DC converter.

As can be seen from the above description, according to the present invention, the command value of active power or reactive power changes in a sinusoidal manner, and in particular, the command value of active power changes from positive to negative (that is, the current in the coil 6 decreases). , or if the magnitude relationship of the control delay angles output to each AC/DC converter is reversed when the current changes from negative to positive (that is, the current in the coil 6 increases), the magnitude of each control delay angle Based on the magnitude relationship, it is possible to uniquely identify an AC/DC converter that is always supplied with a large control delay angle and an AC/DC converter that is always controlled with a small control delay angle. And by setting it fixedly, it is possible to prevent the output voltage waveform from changing significantly due to the reversal of the control delay angle of each AC/DC converter. This has the effect of preventing any surge from occurring in the DC output voltage of the AC/DC converter.

FIG. 7 shows an arithmetic processing flow when the present invention is implemented by digital control.

In process 82, data necessary for controlling active power and reactive power, namely Pr, Qr, P, Q, Id
, Ed6 are taken in, and in process 83, control calculations are performed to realize the constant active/constant reactive power control circuit section 121 shown in FIG.

Next, in process 84, arithmetic processing is performed to realize the control delay angle calculating section 122, and a control delay angle signal α10°α is obtained. Calculate.

The determining unit 85 determines the control delay angle signals α1° and α.

Compare the size of α,. ≧α goose. If so, process 86
So α1=α1゜, α2=α,. After that, in step 88, the control delay angle α1. Output α.

On the other hand, α1゜〈α,. In this case, in process 87 α1=α,
. , α=α1°, and after exchanging the large value and the small value, the control delay angle α1. Output α.

〔Effect of the invention〕

According to the present invention, when a plurality of AC/DC converters connected in series are asymmetrically controlled not with the same control delay angle but with their own control delay angles, each of the plurality of control delay angle signals that are the control calculation results is The sizes are compared and arranged in the order of magnitude, and the control delay angles are always supplied to the plurality of AC/DC converters so that the magnitude relationship of each control delay angle supplied to the plurality of AC/DC converters is not reversed. AC/DC converters that are controlled with a large control delay angle and AC/DC converters that are always controlled with a small control delay angle can be uniquely and fixedly set, so several 4i units can be connected in series. The DC output voltage of the AC/DC converter is
This has the effect of preventing voltage jumps from occurring due to changes in the output voltage waveforms of individual AC/DC converters.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the overall configuration of an energy storage device using a coil, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a time chart showing waveforms of various parts for explaining the present invention in detail. , FIG. 4 is a time chart showing waveforms of various parts to explain the operation of the conventional example, FIG. 5 is a block diagram showing a specific example of the comparison output section of FIG. 4, and FIG. The block diagram of the embodiment, FIG. 7, is a flowchart of arithmetic processing when implemented by digital control according to the present invention. DESCRIPTION OF SYMBOLS 12... Active/reactive power control circuit, 121... Leg active/constant reactive power control circuit section, 122... Control delay angle calculation section, 123... Comparison output section, 13... Phase control circuit Representative Patent Attorney Michihito Hiraki ρ → σ Figure 3 Figure 5 Figure 7 60 stitches

Claims (4)

[Claims] (1) Power conversion in which a power conversion device consisting of a plurality of AC/DC converters connected in series and a load are connected in a loop, and the control delay angles of the plurality of AC/DC converters are independently and asymmetrically controlled. In the device control method, each control delay angle of the plurality of AC/DC converters is calculated, and each obtained control delay angle is supplied to the plurality of AC/DC converters according to the magnitude relationship of the values. A method for controlling a power conversion device, characterized in that the control delay angles are supplied to the plurality of AC/DC converters so that the magnitude relationship of each control delay angle is not reversed. (2) Each control delay angle is calculated based on the deviation of the actual measured value of active and reactive power from each command value, and the no-load DC voltage and current. A method of controlling a power conversion device. (3) Power conversion in which a power conversion device consisting of a plurality of AC/DC converters connected in series and a load are connected in a loop, and each control delay angle of the plurality of AC/DC converters is independently and asymmetrically controlled. In the equipment control device, based on the deviation of the actual measured active and reactive power values from each command value, as well as the no-load DC voltage and DC load current,
means for calculating each control delay angle of the plurality of AC/DC converters; means for rearranging the obtained control delay angles according to the magnitude relationship of their values; and each control delay angle rearranged as described above. and means for supplying the angles to the plurality of AC/DC converters in a fixed relationship so that the magnitude relationship of each control delay angle supplied to the plurality of AC/DC converters is not reversed. Control device for power conversion equipment. (4) The control device for a power conversion device according to claim 3, wherein the load is a superconducting coil.