JPH1023763A - Controller for externally excited reverse inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously stably operate an inverter system at a high speed by surely preventing the occurrence of a communication failure even when the fluctuation, waveform distortion, and asymmetry of an AC voltage transiently increase, by providing a tolerance angle controlling the reference value changing means which increases or decreases a tolerance angle control reference value. SOLUTION: An tolerance angle control reference value change circuit 81 inputs a tolerance angle control reference value γ0 and, when the variation of a reverse voltage period γ is transiently large, increase the reference value γ0. A minimum value selection circuit 91 selects a constant tolerance angle control signal from a constant tolerance angle control circuit 73, and inputs the selected control signal to a phase control circuit 92. Therefore, the occurrence of a communication failure can be prevented, because the control circuit 92 performs phase control based on the constant tolerance angle control signal inputted from the selection circuit 91. In addition, an inverter system can be operated continuously stably at a high speed by maintaining the power factor and efficiently of the inverter in a steady state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to an AC / DC conversion system including a DC power transmission device and a frequency conversion device in cooperation with a forward converter and an inverse converter, and performs a constant margin angle control operation to perform DC operation. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a separately-excited inverter that converts electric power into AC power, and more particularly to a control device for a separately-excited inverter that enables continuous high-speed and stable operation of an AC / DC conversion system.

[0002]

2. Description of the Related Art FIG. 8 is a system diagram showing a configuration example of an AC / DC conversion system such as a DC power transmission device and a frequency conversion device. In FIG. 8, a converter 30 configured by a thyristor bridge is connected to an AC system 10 via a converter transformer 20.

A converter 31 is connected to the DC side of the converter 30 via a DC reactor 40, DC lines 50 and 51, and a DC reactor 41. further,
The AC system 11 is connected to the AC side of the converter 31 via the converter transformer 21.

In order to operate the converters 30 and 31,
A DC current is detected by a DC current detector (not shown), and a DC voltage is detected by a DC voltage detector (not shown), and is supplied to the control devices 60 and 61.

Here, the converters 30, 31 are
Performs forward conversion, and the converter 31 performs reverse conversion. In the following description, the converter 30 is referred to as a forward converter,
The converter 31 is called an inverse converter.

In the AC / DC conversion system, the forward converter 30 performs a constant current control operation, and the inverse converter 31 performs a constant voltage control operation or a constant margin angle control operation, so that power is exchanged.

FIG. 9 is a block diagram showing a configuration example of a conventional converter control device, and shows a configuration example of the control device 61 in FIG. 9, the constant current control circuit (ACR) 71 receives the difference between the direct current I _d and the DC current reference value I _dp, and outputs a constant current control signal.

Further, the constant voltage control circuit (AVR) 72
A DC voltage V _d inputs the difference between the DC voltage reference value V _dp, and outputs a constant voltage control signal. Further, the constant margin angle control circuit (AγR) 73 outputs a reverse voltage period γ applied to the inverter 31.
And a margin angle control reference value γ _O , and outputs a constant margin angle control signal.

On the other hand, the minimum value selection circuit (MIN) 91
Each control signal from the constant current control circuit 71, the constant voltage control circuit 72, and the constant margin angle control circuit 73 is input, and a minimum value control signal among them is output.

The phase control circuit 92 receives an output signal from the minimum value selection circuit 91 and outputs a firing signal synchronized with the system voltage of the AC system 11 to the inverter 31. By the way, in the control device for such a converter, in the constant margin angle control circuit 73, as shown in FIG. 9, a fixed value is set as the margin angle control reference value γ _O.

FIG. 10 is a characteristic diagram showing a breakdown of the margin angle control reference value γ _O of the constant margin angle control circuit 73. As shown in FIG. 10, the margin angle control reference value γ _O is set in view of a margin for a control error and AC voltage distortion in a steady state in the turn-off time γ _F of the thyristor element constituting the inverter 31. I have.

When the waveform distortion and asymmetry of the AC voltage are larger than the amount in the assumed state, the fluctuation Δ
is larger than in the steady state, and the margin angle control reference value γ
_The margin assumed when setting _O is insufficient.

That is, when the phase-shifting equipment is turned on and off, and an AC system fault occurs, the waveform distortion and asymmetry of the AC voltage transiently increase from the amount assumed in the steady state, so that the reverse voltage period is increased. If the margin angle control reference value γ _O remains fixed, as in the prior art, the probability that the actual reverse voltage period γ will be shorter than the turn-off time γ _{F of the} thyristor element will increase, and the margin angle Commutation may fail due to shortage.

On the other hand, if the margin angle control reference value γ _O is set large so that commutation does not fail even in such a transient state,
In the steady state, since the control angle of the inverter 31 advances in the direction of 90 degrees, there is a problem that the power factor changes or the loss of the inverter 31 increases. That is, the margin angle control reference value γ _O cannot always be set large in terms of the power factor and the efficiency of the inverter 31 in the steady state.

[0015]

As described above, in the inverter control apparatus applied to the conventional AC / DC conversion system, when the waveform distortion and the asymmetry of the AC voltage transiently increase, the margin angle becomes insufficient. However, there is a problem that commutation failure and increasing the margin angle control reference value are not preferable from the viewpoint of the power factor and efficiency of the inverter in a steady state.

SUMMARY OF THE INVENTION It is an object of the present invention to reliably prevent the occurrence of commutation failure even when the AC voltage fluctuation, waveform distortion, and asymmetry transiently increase, and to achieve a steady state inverter power factor,
It is an object of the present invention to provide a control device for a separately-excited inverter that can maintain high efficiency and continuously perform high-speed and stable operation of the AC / DC conversion system.

[0017]

In order to achieve the above object, the present invention is applied to an AC / DC conversion system including a DC power transmission device and a frequency conversion device, and is based on a reverse voltage period applied to the converter and a margin angle control reference value. In a control device of a separately-excited inverter for converting a DC power into an AC power by performing a constant margin angle control operation, in the invention corresponding to claim 1, a margin angle control reference value varying means for increasing or decreasing a margin angle control reference value. It comprises.

Here, in particular, the margin angle control reference value changing means increases the margin angle control reference value when the fluctuation in the reverse voltage period is transiently large, as described in claim 7. Is preferable.

Therefore, in the control apparatus of the separately excited inverter according to the first and seventh aspects of the present invention, the margin angle control reference value is increased when the fluctuation of the reverse voltage period is transiently large. Thereby, even if the AC voltage fluctuation and the asymmetry are larger than expected, the control phase is advanced,
Commutation failure can be reliably prevented from occurring.

In the invention corresponding to claim 2, a margin angle control reference value varying means for increasing or decreasing the margin angle control reference value,
Waveform distortion detecting means for detecting the amount of distortion of the AC voltage waveform of the AC system connected to the separately-excited inverter, and outputting the rate of increase or decrease of the margin angle control reference value to the margin angle control reference value varying means; The margin angle control reference value is increased or decreased according to the amount of waveform distortion of the AC voltage.

Therefore, in the control device for the separately excited inverter according to the second aspect of the present invention, the margin angle control reference value is increased or decreased in accordance with the amount of waveform distortion of the AC voltage, so that the AC voltage waveform of the AC system is increased. Even if distortion occurs, the control phase can be advanced to reliably prevent the occurrence of commutation failure.

Further, in the invention corresponding to claim 3, a margin angle control reference value varying means for increasing / decreasing a margin angle control reference value, a commutation failure is detected, and a commutation failure detection signal is supplied to the margin angle control reference value variable. And a commutation failure detection means for outputting a commutation failure detection signal to the control means.

Therefore, in the control device of the separately-excited inverter according to the third aspect of the present invention, the commutation failure is detected by increasing or decreasing the margin angle control reference value by the commutation failure detection signal. By advancing the control phase, the recovery from the commutation failure can be accelerated, and the commutation failure can be reliably prevented from continuing.

On the other hand, in the invention corresponding to claim 4, a margin angle control reference value varying means for increasing or decreasing the margin angle control reference value,
External device input signal receiving means for receiving an input signal of the external device to the AC system and outputting the received signal to the margin angle control reference value varying means, and comprising a margin angle according to the received signal of the external device input signal. The control reference value is increased or decreased.

Therefore, in the control device for the separately excited inverter according to the fourth aspect of the present invention, the margin angle control reference value is increased or decreased by the reception signal of the external device input signal,
Even when an external device is input to the AC system, the control phase can be advanced to reliably prevent the occurrence of commutation failure due to the input of the external device.

In the invention corresponding to claim 5, a margin angle control reference value varying means for increasing or decreasing the margin angle control reference value,
Waveform distortion detecting means for detecting an AC voltage value of an AC system connected to the separately-excited inverter and outputting a rate of increase or decrease of the margin angle control reference value to the margin angle control reference value varying means. The margin angle control reference value is increased or decreased according to the amount of decrease in the AC voltage.

Therefore, in the control device of the separately excited inverter according to the fifth aspect of the present invention, the reference value of the margin angle control is increased or decreased according to the amount of decrease in the AC voltage, so that the AC voltage value of the AC system is reduced. Even if it decreases, advance the control phase,
Commutation failure can be reliably prevented from occurring.

Further, in the invention corresponding to claim 6, the increasing speed and the decreasing speed are configured to be different from each other, and a margin angle control reference value varying means for increasing / decreasing the margin angle control reference value; A margin angle control reference value variable control means for detecting occurrence or attenuation and outputting an increase / decrease command to the margin angle control reference value variable means, and increasing / decreasing the margin angle control reference value by the increase / decrease command. ing.

Therefore, in the control device for the separately excited inverter according to the sixth aspect of the present invention, when the occurrence of a transient phenomenon is detected, the margin angle control reference value is rapidly increased. By slowing down the angle control reference value, the recovery from commutation failure can be accelerated in the event of a transient, and the fluctuation in the reverse voltage period will be large if the transient is attenuated. Even if this happens, the occurrence of commutation failure due to excessive return of the control phase can be reliably prevented.

As described above, by increasing or decreasing the margin angle control reference value, the fluctuation of the AC voltage, the waveform distortion and the asymmetry become larger than the amount assumed in the steady state, and the fluctuation in the reverse voltage period becomes smaller. Even when the commutation failure may occur due to the increase, the control phase can be advanced by increasing the margin angle control reference value, so that the occurrence of commutation failure can be reliably prevented.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a configuration example of a control device of a separately-excited inverse converter according to the present embodiment. The same parts as those in FIG. And
Here, only different parts will be described.

That is, as shown in FIG. 1, the control device for the separately-excited inverse converter of this embodiment includes a margin angle control reference value variable circuit 8 at the input stage of the constant margin angle control circuit 73 in FIG.
1 is provided.

Here, the margin angle control reference value variable circuit 81
Is for inputting the margin angle control reference value γ _O and increasing or decreasing the magnitude. Particularly, in this embodiment, when the fluctuation of the reverse voltage period γ is transiently large, the margin angle control reference value γ _O is increased.

Next, the operation of the control device for the separately-excited inverse converter according to this embodiment configured as described above will be described. In FIG. 1, when the fluctuation of the reverse voltage period γ is transiently large, the margin angle control reference value γ _O is increased by the margin angle control reference value variable circuit 81.

On the other hand, in the constant margin angle control circuit 73, the control calculation shown in the following equation is performed. Therefore, by increasing the margin angle control reference value γ _O , the constant margin angle control circuit 73 outputs the constant margin angle control circuit 73. The margin angle control signal becomes smaller.

Output of constant margin angle control circuit 73 = cos
^{_{-1 [(X t · I d}} ) / V ac -cosγ O] Here, X _t: In AC voltage as a result, the minimum value selection circuit (MIN) 91: commutation reactance I _d: direct current value V _ac The constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, the ignition signal synchronized with the system voltage of the AC system 11 is output from the phase control circuit 92 to the converter 31 based on the constant margin angle control signal output signal from the minimum value selection circuit 91. The control phase is advanced to prevent the occurrence of commutation failure.

That is, when the AC voltage fluctuation or the asymmetry is larger than the expected amount, the fluctuation of the reverse voltage period γ becomes larger than that in the steady state, and the variation in the margin angle control reference value γ _O in the steady operation becomes smaller. There is a risk of flow failure.

Therefore, in this case, the margin angle control reference value γ _O
Is increased, the control phase advances, and as a result, the reverse voltage period γ increases, and even if the amount of change Δγ in the reverse voltage period γ increases, the turn-off time γ _F of the thyristor element constituting the inverter 31 increases. It is no longer short, and the occurrence of commutation failure can be reliably prevented.

As described above, the control device for the separately-excited inverse converter according to the present embodiment inputs the margin angle control reference value γ _O ,
A margin angle control reference value variable circuit 81 for increasing or decreasing the magnitude is provided, and when the fluctuation of the reverse voltage period γ is transiently large,
This is to increase the margin angle control reference value γ _O.

Therefore, when the fluctuation of the reverse voltage period γ is transiently large, the margin angle control reference value γ _O is increased, so that when the AC voltage fluctuation or the asymmetry is larger than the expected amount. However, it is possible to advance the control phase to reliably prevent the occurrence of commutation failure.

In order to prevent commutation failure even in a transient state, it is not necessary to always increase the margin angle control reference value γ _O , unlike the above-mentioned conventional case, so that the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated.

As described above, the high-speed and stable operation of the AC / DC conversion system can be continuously performed. (Second Embodiment) FIG. 2 is a block diagram showing a configuration example of a control device of a separately-excited inverse converter according to the present embodiment. The same parts as those in FIG. And
Here, only different parts will be described.

That is, as shown in FIG. 2, the control device of the separately-excited inverse converter of the present embodiment has a configuration in which a waveform distortion detection circuit 82 is provided in addition to FIG. Here, the waveform distortion detection circuit 82 detects the amount of distortion of the AC voltage waveform of the AC system 11 connected to the inverter 31 and determines the rate of increase or decrease of the margin angle control reference value γ _O as the margin angle control reference value. Variable circuit 8
The margin angle control reference value γ _O is increased or decreased according to the amount of waveform distortion of the AC voltage.

Next, the operation of the control device for the separately-excited inverter of the present embodiment configured as described above will be described. In FIG. 2, the waveform distortion detection circuit 82 detects the amount of distortion of the AC voltage waveform of the AC system 11 connected to the inverter 31, and determines the rate of increase or decrease of the margin angle control reference value γ _{O by} the margin angle control reference value. Output to the variable circuit 81.

Here, when the waveform distortion amount of the AC voltage is large, the margin angle control reference value variable circuit 81 increases the margin angle control reference value γ _O in accordance with the waveform distortion amount of the AC voltage.

On the other hand, in the constant margin angle control circuit 73, since the control calculation shown in the above equation is performed, the constant margin angle control circuit 7 is increased by increasing the margin angle control reference value γ _O.
3 decreases the constant margin angle control signal.

As a result, the minimum value selection circuit (MIN) 91
Then, the constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, the ignition signal synchronized with the system voltage of the AC system 11 is output from the phase control circuit 92 to the converter 31 based on the constant margin angle control signal output signal from the minimum value selection circuit 91. The control phase is advanced to prevent the occurrence of commutation failure.

That is, if the waveform of the AC voltage is distorted, the intersection with the zero point of the AC voltage is temporally advanced as compared with the steady state, and the reverse voltage period γ is reduced, which may cause a commutation failure. .

Therefore, in this case, since the margin angle control reference value γ _O can be varied in accordance with the amount of waveform distortion of the AC voltage, the waveform of the AC voltage is more distorted than expected and the reverse voltage period γ becomes longer. If it becomes smaller, the margin angle control reference value γ
By increasing _O , the control phase advances, and as a result, the reverse voltage period γ increases, and the occurrence of commutation failure can be reliably prevented.

As described above, in the control device for the separately-excited inverse converter according to the present embodiment, the margin angle control reference value γ _O is input,
Margin angle control reference value variable circuit 81 for increasing or decreasing the size
And the amount of distortion of the AC voltage waveform of the AC system 11 connected to the inverter 31 and outputs the rate of increase or decrease of the margin angle control reference value γ _O to the margin angle control reference value variable circuit 81. A waveform distortion detection circuit 82 is provided to increase or decrease the margin angle control reference value γ _O in accordance with the amount of waveform distortion of the AC voltage.

Therefore, since the margin angle control reference value γ _O is increased or decreased according to the amount of waveform distortion of the AC voltage, the control phase is advanced even if the AC voltage waveform of the AC system 11 is distorted. In addition, the occurrence of commutation failure can be reliably prevented.

In order to prevent commutation failure even in a transient state, it is not necessary to always increase the margin angle control reference value γ _O , unlike the above-described conventional case, so that the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated.

As described above, high-speed and stable operation of the AC / DC conversion system can be continuously performed. (Third Embodiment) FIG. 3 is a block diagram showing a configuration example of a control device for a separately-excited inverse converter according to the present embodiment. The same reference numerals are given to the same parts as in FIG. 1 and the description is omitted. And
Here, only different parts will be described.

That is, as shown in FIG. 3, the control device of the separately-excited inverter of this embodiment has a configuration in which a commutation failure detection circuit 83 is provided in addition to FIG. Here, the commutation failure detection circuit 83 detects a commutation failure and outputs a commutation failure detection signal to the margin angle control reference value variable circuit 81. The reference value γ _O is increased or decreased.

Next, the operation of the control device for the separately-excited inverse converter constructed as described above according to this embodiment will be described. 3, a commutation failure is detected by a commutation failure detection circuit 83, and a commutation failure detection signal is output to a margin angle control reference value variable circuit 81.

Thus, the margin angle control reference value variable circuit 8
By 1, the margin angle control reference value γ _O is increased. On the other hand, in the constant margin angle control circuit 73, since the control calculation shown in the above equation is performed, by increasing the margin angle control reference value γ _O , the constant margin angle control circuit 73 outputs the constant margin angle The angle control signal becomes smaller.

As a result, the minimum value selection circuit (MIN) 91
Then, the constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, based on the constant margin angle control signal output signal from the minimum value selection circuit 91, the phase control circuit 92 outputs an ignition signal synchronized with the system voltage of the AC system 11 to the converter 31. , The control phase is advanced and the commutation failure can be prevented from continuing.

That is, when a commutation failure occurs, it is necessary to promptly advance the control phase to increase the reverse voltage period γ to recover from the commutation failure. Therefore, in this case, the control phase can be advanced more quickly by detecting the commutation failure and increasing the margin angle control reference value γ _O , so that the recovery from the commutation failure becomes faster, and as a result, It is possible to reliably prevent the flow failure from continuing.

As described above, in the control device for the separately-excited inverse converter according to the present embodiment, the margin angle control reference value γ _O is input, and
Margin angle control reference value variable circuit 81 for increasing or decreasing the size
And a commutation failure detection circuit 83 which detects a commutation failure and outputs a commutation failure detection signal to the margin angle control reference value variable circuit 81. γ _O is increased or decreased.

Therefore, since the margin angle control reference value γ _O is increased or decreased by the commutation failure detection signal, even if a commutation failure occurs, the control phase is advanced to quickly recover from the commutation failure. Thus, it is possible to reliably prevent the commutation failure from continuing.

In order to prevent commutation failure even in a transient state, it is not necessary to always increase the margin angle control reference value γ _O , unlike the above-mentioned conventional case, so that the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated.

As described above, high-speed and stable operation of the AC / DC conversion system can be continuously performed. (Fourth Embodiment) FIG. 4 is a block diagram showing a configuration example of a control device of a separately-excited inverse converter according to the present embodiment. The same parts as those in FIG. And
Here, only different parts will be described.

That is, as shown in FIG. 4, the control device of the separately-excited inverse converter of this embodiment has a configuration in which an external device input signal receiving circuit 84 is provided in addition to FIG. Here, the external device input signal receiving circuit 84 receives an external device input signal to the AC system 11 and outputs the received signal to the margin angle control reference value variable circuit 81. The margin angle control reference value γ _O is increased or decreased according to the received signal.

Next, the operation of the control device for the separately-excited inverse converter according to this embodiment configured as described above will be described. In FIG. 4, the external device input signal receiving circuit 84
The input of the external device is detected, and the external device input reception signal is output to the margin angle control reference value variable circuit 81.

Thus, the margin angle control reference value variable circuit 8
By 1, the margin angle control reference value γ _O is increased. On the other hand, in the constant margin angle control circuit 73, since the control calculation shown in the above equation is performed, by increasing the margin angle control reference value γ _O , the constant margin angle control circuit 73 outputs the constant margin angle The angle control signal becomes smaller.

As a result, the minimum value selection circuit (MIN) 91
Then, the constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, based on the constant margin angle control signal output signal from the minimum value selection circuit 91, the phase control circuit 92 outputs an ignition signal synchronized with the system voltage of the AC system 11 to the converter 31. The control phase is advanced to prevent the occurrence of commutation failure.

That is, when an external device is supplied to the AC system 11, the AC voltage fluctuates and distorts, and the reverse voltage period γ becomes smaller than in a steady state, which may cause a commutation failure.

In this case, since the timing at which the external device is actually turned on is usually later than the timing at which the external device is turned on, the turning-on of the external device is detected and the margin angle control reference value γ _O is increased. By doing so, the control phase can be advanced in advance, so that the occurrence of commutation failure due to the input of external equipment can be reliably prevented.

As described above, in the control device for the separately-excited inverse converter according to the present embodiment, the margin angle control reference value γ _O is input,
Margin angle control reference value variable circuit 81 for increasing or decreasing the size
And an external device input signal receiving circuit 84 that receives an external device input signal to the AC system 11 and outputs the received signal to the margin angle control reference value variable circuit 81. The margin angle control reference value γ _O is increased or decreased by a signal.

Accordingly, since the margin angle control reference value γ _O is increased or decreased by the received signal of the external device input signal, even if the external device is input to the AC system 11, the control phase is advanced and the external device is advanced. It is possible to reliably prevent the occurrence of commutation failure due to charging.

In order to prevent commutation failure even in a transient state, it is not necessary to always increase the margin angle control reference value γ _O , unlike the above-mentioned conventional case, so that the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated.

As described above, high-speed and stable operation of the AC / DC conversion system can be continuously performed. (Fifth Embodiment) FIG. 5 is a block diagram showing a configuration example of a control device of a separately-excited inverse converter according to the present embodiment. The same parts as those in FIG. And
Here, only different parts will be described.

That is, as shown in FIG. 5, the control device of the separately-excited inverter of the present embodiment has an AC voltage value detection circuit 85 in addition to FIG. Here, the AC voltage value detection circuit 85 detects the AC voltage value of the AC system 11 connected to the inverter 31 and outputs the margin angle control reference value γ.
The rate of increase or decrease of _O is output to the margin angle control reference value variable circuit 81, and the margin angle control reference value γ _O is increased or decreased according to the amount of decrease in the AC voltage.

Next, the operation of the control device for a separately-excited inverter of the present embodiment configured as described above will be described. In FIG. 5, an AC voltage value detection circuit 85 detects an AC voltage value of the AC system 11 connected to the inverter 31 and determines a rate of increase or decrease of the margin angle control reference value γ _{O by} a margin angle control reference value variable circuit 81. Is output to

Here, when the AC voltage value decreases,
The margin angle control reference value variable circuit 81 increases the margin angle control reference value γ _O in accordance with the amount of decrease in the AC voltage. On the other hand, in the constant margin angle control circuit 73, since the control calculation shown in the above equation is performed, by increasing the margin angle control reference value γ _O , the constant margin angle control circuit 73 outputs the constant margin angle The angle control signal becomes smaller.

As a result, the minimum value selection circuit (MIN) 91
Then, the constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, based on the constant margin angle control signal output signal from minimum value selection circuit 91, phase control circuit 92 outputs an ignition signal synchronized with system voltage of AC system 11 to converter 31. The control phase is advanced to prevent the occurrence of commutation failure.

That is, when the AC voltage value decreases,
Correspondingly, the reverse voltage period γ becomes smaller, which may cause a commutation failure. Therefore, in this case, since the margin angle control reference value γ _O can be varied according to the decrease in the AC voltage value, when the AC voltage value decreases and the reverse voltage period γ decreases, the margin angle By increasing the control reference value γ _O , the control phase advances, and as a result, the reverse voltage period γ
Can always be made longer than the turn-off time γ _F of the thyristor element constituting the inverter 31, and the occurrence of commutation failure can be reliably prevented.

As described above, the control device of the separately-excited inverse converter according to the present embodiment receives the margin angle control reference value γ _O ,
Margin angle control reference value variable circuit 81 for increasing or decreasing the size
AC voltage value detection for detecting the AC voltage value of the AC system 11 connected to the inverter 31 and outputting the rate of increase or decrease of the margin angle control reference value γ _O to the margin angle control reference value variable circuit 81. A circuit 85 is provided to increase or decrease the margin angle control reference value γ _O in accordance with the amount of decrease in the AC voltage.

Therefore, since the margin angle control reference value γ _O is increased or decreased in accordance with the amount of decrease in the AC voltage, even if the AC voltage value of the AC system 11 decreases, the control phase is advanced and commutation is performed. Failure can be reliably prevented from occurring.

In order to prevent commutation failure even in a transient state, it is not necessary to always increase the margin angle control reference value γ _O , unlike the above-mentioned conventional case, so that the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated.

As described above, high-speed and stable operation of the AC / DC conversion system can be continuously performed. (Sixth Embodiment) FIG. 6 is a block diagram showing a configuration example of a control device of a separately-excited inverse converter according to the present embodiment, and the same parts as those in FIG. And
Here, only different parts will be described.

That is, in the control device of the separately-excited inverter of the present embodiment, as shown in FIG. 6, the margin angle control reference value variable circuit 81 in FIG. 1 is omitted. In the input stage of the angle control circuit 73, a margin angle control reference value variable circuit 86 and a margin angle control reference value variable control circuit 87 are provided.

Here, the margin angle control reference value variable circuit 86
Is configured such that the increasing speed and the decreasing speed are different from each other, and the margin angle control reference value γ _O is input to increase or decrease the magnitude.

The margin angle control reference value variable control circuit 87
Detects the occurrence or decay of a transient phenomenon and outputs an increase / decrease command to the margin angle control reference value variable circuit 86, and increases / decreases the margin angle control reference value γ _O by the increase / decrease instruction. .

The margin angle control reference value variable control circuit 87 can be, for example, an AC system fault detection circuit, a commutation failure detection circuit, an AC voltage waveform distortion detection circuit, or the like.

Next, the operation of the control device for the separately-excited inverse converter constructed as described above according to this embodiment will be described. In FIG. 6, when the occurrence of a transient phenomenon is detected by the margin angle control reference value variable control circuit 87, the margin angle control reference value γ _O is increased at a high speed by the margin angle control reference value variable circuit 86. You.

The margin angle control reference value variable control circuit 87
When the transient phenomenon attenuation is detected, the margin angle control reference value variable circuit 86 reduces the margin angle control reference value γ _O at a low speed.

As a result, the minimum value selection circuit (MIN) 91
Then, the constant margin angle control signal from the constant margin angle control circuit 73 is selected, and the constant margin angle control signal is input to the phase control circuit 92.

Thus, based on the constant margin angle control signal output signal from minimum value selection circuit 91, phase control circuit 92 outputs an ignition signal synchronized with system voltage of AC system 11 to converter 31. You.

That is, when the occurrence of a transient phenomenon is detected, the control phase is advanced at a high speed by the minimum value selecting circuit 91. When the attenuation of the transient phenomenon is detected, the minimum value selecting circuit 91 is used. Due to 91, the control phase is returned at a slow speed.

FIG. 7 is a time chart showing the state of each signal of the present control device at the time of an AC system accident. That is, in FIG. 7, it is assumed that an accident has occurred in the AC system 11 at time t ₁ and the AC system 11 has recovered at time t ₂ .

When an accident occurs at time t ₁ , the accident is detected by the margin angle control reference value variable control circuit 87, and the margin angle control reference value γ is output by the margin angle control reference value variable circuit 86.
_O is increased at a high speed, and the control phase is advanced quickly by the constant margin angle control circuit 73.

Next, when the accident is recovered at time t ₂ , the value of the AC voltage of the AC system 11 returns, and the reverse voltage period γ sharply increases. However, in this case, the margin angle control reference value γ _O
Is reduced at a low speed by the margin angle control reference value variable circuit 86, so that the control phase returns little, and the control phase returns slowly as the margin angle control reference value γ _O gradually decreases.

As described above, when a transient phenomenon occurs, the margin voltage control reference value γ _O is increased quickly to advance the control phase more quickly, so that the reverse voltage period γ increases more quickly and recovery from commutation failure occurs. Can be faster.

Further, when the transient phenomenon is attenuated, the margin angle control reference value γ _O is slowly reduced and the control phase is returned slowly. Commutation failure due to excessive return can be reliably prevented.

As described above, the control device of the separately-excited inverter of this embodiment is configured so that the increasing speed and the decreasing speed are different from each other, and the margin angle control reference value γ
_O is input, a margin angle control reference value variable circuit 86 for increasing or decreasing the magnitude, and the occurrence or attenuation of a transient phenomenon is detected,
A margin angle control reference value variable control circuit 87 that outputs an increase / decrease command to the margin angle control reference value variable circuit 86;
The margin angle control reference value γ _O is increased or decreased by an increase / decrease command.

Therefore, when the occurrence of a transient phenomenon is detected, the margin angle control reference value γ _O is rapidly increased, and when the decay of the transient phenomenon is detected, the margin angle control reference value γ _O is decreased slowly. If a phenomenon occurs, recovery from commutation failure can be accelerated, and if the transient phenomenon attenuates, even if the reverse voltage period fluctuates significantly, the control phase will return due to excessive return of the control phase. It is possible to reliably prevent the occurrence of flow failure.

Further, since it is not necessary to always increase the margin angle control reference value γ _O as in the above-described conventional method so that commutation does not fail even in a transient state, the power factor of the inverter 31 varies. Or an increase in the loss of the inverter 31 can be eliminated. As described above, high-speed and stable operation of the AC / DC conversion system can be continuously performed.

[0104]

As described above, the present invention is applied to the AC / DC conversion system including the DC power transmission device and the frequency conversion device, and performs the constant margin angle control operation based on the reverse voltage period applied to the converter and the margin angle control reference value. According to the invention corresponding to claim 1 and claim 7, a margin angle control reference value varying means for increasing / decreasing a margin angle control reference value is provided. When the fluctuation of the reverse voltage period is transiently large, the margin angle control reference value is increased, so that the AC voltage fluctuation, waveform distortion,
Even if the asymmetry increases transiently, the control phase is advanced to reliably prevent the occurrence of commutation failure, and to maintain the inverter power factor and efficiency in the steady state to achieve the high speed and high speed of the AC / DC conversion system. It is possible to provide a control device for a separately-excited inverter capable of continuously performing a stable operation.

According to the second aspect of the present invention,
A margin angle control reference value varying means for increasing or decreasing the margin angle control reference value, and detecting the amount of distortion of the AC voltage waveform of the AC system connected to the separately-excited inverter, and determining the rate of increase or decrease of the margin angle control reference value. A waveform distortion detecting means for outputting to the margin angle control reference value varying means to increase or decrease the margin angle control reference value in accordance with the amount of waveform distortion of the AC voltage. Even if distortion occurs, advance the control phase to reliably prevent the occurrence of commutation failure, and maintain the inverter power factor and efficiency in the steady state to operate the AC / DC conversion system at high speed and stable operation. A control device for a separately-excited inverter that can be continuously performed can be provided.

Further, according to the invention corresponding to claim 3, a margin angle control reference value varying means for increasing / decreasing the margin angle control reference value, a commutation failure is detected, and the commutation failure detection signal is supplied to the margin angle control reference value. A commutation failure detection means for outputting to the value variable means, and the margin angle control reference value is increased or decreased by a commutation failure detection signal, so that even if a commutation failure occurs, the control phase is advanced. To speed up recovery from commutation failure,
Separately-excited type that can reliably prevent continuous commutation failure and maintain the inverter's power factor and efficiency in a steady state, and continue high-speed and stable operation of the AC / DC conversion system A control device for the inverter can be provided.

On the other hand, according to the invention corresponding to claim 4,
A margin angle control reference value varying means for increasing / decreasing a margin angle control reference value, and an external equipment input signal receiving means for receiving an input signal of an external device to the AC system and outputting a received signal to the margin angle control reference value varying means. Means to increase or decrease the margin angle control reference value according to the reception signal of the external device input signal, so that even when the external device is input to the AC system, the control phase is advanced and commutation due to external device input is performed. A separately-excited inverter that can reliably prevent the occurrence of failures and maintain the inverter's power factor and efficiency in a steady state and can continue high-speed and stable operation of the AC / DC conversion system A control device can be provided.

According to the invention corresponding to claim 5,
A margin angle control reference value varying means for increasing and decreasing the margin angle control reference value, and detecting an AC voltage value of an AC system connected to the separately-excited inverter, and determining a rate of increase or decrease of the margin angle control reference value. A waveform distortion detecting means for outputting to the value varying means is provided, so that the margin angle control reference value is increased or decreased according to the amount of decrease in the AC voltage, so that even when the AC voltage value of the AC system decreases, Advances the control phase to reliably prevent the occurrence of commutation failure, and maintains the inverter power factor and efficiency in the steady state, enabling continuous high-speed and stable operation of the AC / DC conversion system. A control device for a separately-excited inverter can be provided.

Further, according to the invention corresponding to claim 6, the increasing speed and the decreasing speed are configured to be different from each other, and a margin angle control reference value varying means for increasing / decreasing the margin angle control reference value; A margin angle control reference value variable control means for detecting the occurrence or attenuation of the phenomenon and outputting an increase / decrease command to the margin angle control reference value variable means, and increasing / decreasing the margin angle control reference value by the increase / decrease command. Therefore, when a transient phenomenon occurs, the recovery from the commutation failure can be accelerated, and when the transient phenomenon is attenuated, even if the fluctuation of the reverse voltage period increases, the control phase In addition to being able to reliably prevent the occurrence of commutation failure due to excessive return, maintain the inverter power factor and efficiency in a steady state, and continue high-speed and stable operation of the AC / DC conversion system. Excitation type inverter control Apparatus can be provided.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a control device for a separately-excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 2 shows a second embodiment of the control device of the separately excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 3 shows a third embodiment of the control device for the separately excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 4 shows a fourth embodiment of the control device for the separately excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 5 shows a fifth embodiment of the control device for the separately excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 6 shows a sixth embodiment of the control device of the separately excited inverter according to the present invention.
FIG. 2 is a block diagram showing an embodiment.

FIG. 7 is a time chart for explaining the operation of the control device for the separately-excited inverter in the sixth embodiment.

FIG. 8 is a system diagram showing a configuration example of an AC / DC conversion system such as a DC power transmission device and a frequency conversion device.

FIG. 9 is a block diagram showing a configuration example of a conventional converter control device.

FIG. 10 is a characteristic diagram showing a breakdown of a margin angle control reference value γ _O of the constant margin angle control circuit in FIG. 9;

[Explanation of symbols]

10, 11: AC system, 20, 21: Transformer transformer, 30: Forward converter, 31: Inverter, 40, 41: DC reactor, 50, 51: DC line, 60, 61: Control device, 71 ... constant current control circuit (ACR), 72 ... constant voltage control circuit (AVR), 73 ... constant margin angle control circuit (AγR), 81 ... margin angle control reference value variable circuit, 82 ... waveform distortion detection circuit, 83 ... Flow failure detection circuit, 84: external device input signal receiving circuit, 85: AC voltage value detection circuit, 86: margin angle control reference value variable circuit, 87: margin angle control reference value variable control circuit, 91: minimum value selection circuit ( MIN), 92 ... phase control circuit, I _d ... DC current, I _dp ... DC current reference value, V _d ... DC voltage, V _dp ... DC voltage reference value, gamma ... reverse voltage period, gamma _O ... margin angle control criteria value.

Claims (7)

[Claims] The present invention is applied to an AC / DC conversion system including a DC power transmission device and a frequency conversion device, and performs a constant margin angle control operation based on a reverse voltage period applied to the converter and a margin angle control reference value to convert DC power into AC power. A control device for a separately-excited inverter, comprising: a margin-angle control reference value variable unit that increases / decreases the margin-angle control reference value. 2. An AC / DC conversion system including a DC power transmission device and a frequency conversion device, wherein a constant margin angle control operation is performed based on a reverse voltage period applied to the converter and a margin angle control reference value to convert DC power into AC power. In the control device of the separately-excited inverter, which converts the margin-angle control reference value into and out, a margin-angle control reference value variable unit that increases or decreases the margin-angle control reference value; Waveform distortion detecting means for detecting an amount of the marginal angle control reference value and outputting the rate of increase or decrease to the margin angle control reference value varying means, and the margin according to the waveform distortion amount of the AC voltage. A control device for a separately-excited inverter, wherein an angle control reference value is increased or decreased. 3. An AC-DC conversion system including a DC power transmission device and a frequency conversion device, wherein a constant margin angle control operation is performed based on a reverse voltage period applied to the converter and a margin angle control reference value to convert DC power into AC power. In the control device of the separately-excited inverse converter for converting into a margin angle control reference value varying means for increasing or decreasing the margin angle control reference value, detecting a commutation failure, and outputting a commutation failure detection signal to the margin angle control reference value A commutation failure detecting means for outputting to the variable means, wherein the marginal angle control reference value is increased or decreased by the commutation failure detection signal. . 4. An AC / DC conversion system including a DC power transmission device and a frequency conversion device, and performs a constant margin angle control operation based on a reverse voltage period applied to the converter and a margin angle control reference value to convert DC power into AC power. In the control device of the separately-excited inverse converter for converting into a margin angle control reference value varying means for increasing or decreasing the margin angle control reference value, receiving a signal of inputting an external device to the AC system, and converting the received signal into the margin External device input signal receiving means for outputting to the angle control reference value varying means, wherein the margin angle control reference value is increased or decreased by a reception signal of the external device input signal. Control device for inverting inverter. 5. An AC / DC conversion system including a DC power transmission device and a frequency conversion device, wherein a constant margin angle control operation based on a reverse voltage period applied to the converter and a margin angle control reference value is performed to convert DC power into AC power. In the control device of the separately-excited inverter, which converts the margin angle control reference value into and out, and detects an AC voltage value of an AC system connected to the separately-excited inverse converter. And a waveform distortion detecting means for outputting a rate of increase or decrease of the margin angle control reference value to the margin angle control reference value varying means, wherein the margin angle control reference value is changed in accordance with the decrease amount of the AC voltage. A control device for a separately-excited inverter, wherein the control device is configured to increase or decrease. 6. Applied to an AC / DC conversion system including a DC power transmission device and a frequency conversion device, and performs a constant margin angle control operation based on a reverse voltage period applied to the converter and a margin angle control reference value to convert DC power into AC power. In the control device of the separately-excited inverter, the speed of increase and the speed of decrease are configured to be different from each other, and a margin angle control reference value variable means for increasing or decreasing the margin angle control reference value; A margin angle control reference value variable control means for detecting occurrence or attenuation and outputting an increase / decrease command to the margin angle control reference value variable means, and increasing / decreasing the margin angle control reference value by the increase / decrease command. A control device for a separately-excited inverse converter, characterized in that: 7. The margin angle control reference value varying means increases the margin angle control reference value when the fluctuation of the reverse voltage period is transiently large. The control device of the separately-excited inverter described in the above.