JP2783765B2 - Control device for power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a power converter for detecting an AC system accident and preventing commutation failure of the power converter.

[0002]

2. Description of the Related Art FIG. 17 is a block diagram showing a conventional control device for a power converter. In the figure, reference numeral 1 denotes an AC system, 2 denotes a transformer, and 3 denotes a transformer connected to an AC system 1 via a transformer 2. , Power converters for converting AC power to DC power, 4a, 4b,
4c is an AC voltage detector (commutation voltage detecting means) for detecting a phase voltage of the AC system 1, and 5a, 5b and 5c are AC system detectors.
Is a subtractor (commutation voltage detecting means) for calculating the commutation voltage (line voltage) of each switching element constituting the power converter 3 from the phase voltage of (1).

[0003] Also, 6a, 6b, 6c are subtracters 5a-5.
filters for removing harmonic components from the commutation voltage calculated by c; 7a, 7b and 7c mean commutation voltage detection for calculating the average value of the amplitude of the commutation voltage from which the harmonic components have been removed by the filters 6a to 6c 8a, 8b, 8c are accident detectors for judging that an accident has occurred in the AC system 1 when the average value of the commutation voltages calculated by the average commutation voltage detectors 7a to 7c deviates from the allowable voltage range. 9 is an accident detector 8a-
When any of 8c detects an accident in the AC system 1, an OR circuit 10 that outputs an accident detection signal is a controller that controls the control angle of the power converter 3.

Next, the operation will be described. First, the AC voltage detectors 4a to 4c detect the instantaneous value of the phase voltage of the AC system 1, and the subtractors 5a to 5c output the power converter 3
The commutation voltage of each switching element that constitutes the above is obtained. However, since the commutation voltage contains a harmonic component in addition to the fundamental wave component, the average commutation voltage detectors 7a to 7c at the subsequent stages detect the amplitude of the commutation voltage if the commutation voltage remains unchanged. Therefore, the filters 6a to 6c receive the commutation voltage and remove harmonic components contained in the commutation voltage.

When the harmonic components are removed by the filters 6a to 6c, the average commutation voltage detectors 7a to 7c detect the amplitude of the commutation voltage and calculate the average value of the amplitude of each phase. However, filters 6a to 6c for removing harmonic components
Have phase characteristics, the average commutation voltage detectors 7a to 7
c has to wait for the conversion of the commutation voltage by the amount of the phase characteristic, and takes several tens of milliseconds until the average value of the amplitude of the commutation voltage is obtained.
It takes time. The average commutation voltage detectors 7a to 7a
7c is, for example, "Response Characteristics and Stabilization Control of DC System to AC System Unbalance Failure" Transactions of the Institute of Electrical Engineers of Japan, Vol.
No. pages 27 to 35 disclosed in 1992.

When the average value of the commutation voltage is obtained in this way, the fault detectors 8a to 8c monitor the average value of the commutation voltage, and the average value deviates from the allowable voltage range. Then, it is determined that an accident has occurred in the AC system 1.
When any of the fault detectors 8a to 8c detects a fault in the AC system 1, the OR circuit 9 outputs a fault detection signal to the controller 10, and when the controller 10 receives the fault detection signal, the power conversion is performed. The power converter 3 is stopped to prevent the commutation failure of the power converter 3 due to the accident of the AC system 1.

[0007]

Since the conventional power converter control device is configured as described above, it is necessary to detect the amplitude of the commutation voltage and calculate the average value of the amplitude. 3 is controlled, since it is necessary to remove the higher harmonic components included in the commutation voltage by the filters 6a to 6c having phase characteristics in order to detect the amplitude of the commutation voltage. 6c (several tens of msec), the average value of the amplitude of the commutation voltage cannot be calculated. As a result, even if the commutation voltage fluctuates due to an accident or the like, the power converter 3 cannot be operated immediately. Therefore, there is a problem that the control margin angle cannot be secured, commutation failure occurs, power cannot be transmitted, and the AC system 1 is disturbed.

[0008] The present invention has been made to solve the above problems, and even if an accident occurs in the AC system,
An object of the present invention is to provide a control device for a power converter that can reliably prevent a commutation failure of each switching element included in the power converter.

[0009]

According to a first aspect of the present invention, there is provided a control device for a power converter, wherein when a ratio of a sine wave component and a cosine wave component detected by a ratio detecting means deviates from an allowable value, an accident occurs in an AC system. Is determined to have occurred, and the power converter is stopped.

The control device for a power converter according to a second aspect of the present invention determines that an accident has occurred in the AC system when the sine wave component calculated by the sine wave component calculation means deviates from an allowable value. This is to stop the vessel.

A control device for a power converter according to a third aspect of the present invention determines that an accident has occurred in the AC system when the cosine wave component calculated by the cosine wave component calculation means deviates from an allowable value. This is to stop the vessel.

The control device for a power converter according to the present invention determines that an accident has occurred in the AC system when both the sine wave component and the cosine wave component deviate from the allowable values, and stops the power converter. It is intended to be.

The control device for a power converter according to the present invention determines that an accident has occurred in the AC system when the ratio between the sine wave component and the cosine wave component detected by the ratio detecting means deviates from an allowable value. Then, the control angle of each phase in the power converter is reduced.

According to a sixth aspect of the present invention, there is provided a power converter control device, comprising:
Control angle selection means for obtaining the control angle of each phase necessary to prevent commutation failure and selecting the control angle having the smallest value among the control angles of each phase is provided, and each phase in the power converter is provided. Is made to coincide with the control angle selected by the control angle selecting means.

According to a seventh aspect of the present invention, there is provided a power converter control device, comprising:
Control angle determining means for determining the control angle of each phase necessary to prevent commutation failure is provided, and the control angle of each phase in the power converter matches the control angle determined by the control angle determining means. It is intended to be.

The control device for a power converter according to the present invention determines that an accident has occurred in the AC system when the sine wave component calculated by the sine wave component calculation means deviates from an allowable value. The control angle of each phase in the vessel is reduced.

According to a ninth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing a commutation failure based on a sine wave component calculated by a sine wave component calculation means. A control angle selecting means for selecting the control angle having the smallest value among the control angles of the respective phases is provided, and the control angle of each phase in the power converter is set to the control angle selected by the control angle selecting means. It is made to match.

According to a tenth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing commutation failure based on a sine wave component calculated by a sine wave component calculation means. Control angle determining means for determining each of the control angles is provided, and the control angle of each phase in the power converter is matched with the control angle determined by the control angle determining means.

The control device for the power converter according to the present invention determines that an accident has occurred in the AC system when the cosine wave component calculated by the cosine wave component calculation means deviates from the allowable value. The control angle of each phase in the vessel is reduced.

According to a twelfth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing commutation failure based on a cosine wave component calculated by cosine wave component calculation means. A control angle selecting means for selecting the control angle having the smallest value among the control angles of the respective phases is provided, and the control angle of each phase in the power converter is set to the control angle selected by the control angle selecting means. It is made to match.

According to a thirteenth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing commutation failure based on a cosine wave component calculated by cosine wave component calculation means. Control angle determining means for determining each of the control angles is provided, and the control angle of each phase in the power converter is matched with the control angle determined by the control angle determining means.

According to a fourteenth aspect of the present invention, the control device for a power converter determines that an accident has occurred in the AC system when both the sine wave component and the cosine wave component deviate from the allowable values. The control angle of the phase is reduced.

According to a fifteenth aspect of the present invention, a control device for a power converter obtains a control angle of each phase necessary for preventing a commutation failure based on a sine wave component and a cosine wave component. A control angle selecting means for selecting a control angle having the smallest value among the control angles of each phase is provided, and the control angle of each phase in the power converter is made to match the control angle selected by the control angle selecting means. Things.

According to a sixteenth aspect of the present invention, there is provided a power converter control device which determines a control angle of each phase required to prevent a commutation failure based on a sine wave component and a cosine wave component. A determination means is provided so that the control angle of each phase in the power converter is matched with the control angle determined by the control angle determination means.

[0025]

The control device of the power converter according to the first aspect of the present invention determines that an accident has occurred in the AC system when the ratio between the sine wave component and the cosine wave component detected by the ratio detecting means deviates from an allowable value. By providing the control means for stopping the power converter, the power converter can be stopped without a time delay with respect to the fluctuation of the commutation voltage.

The control device for the power converter according to the second aspect of the present invention determines that an accident has occurred in the AC system when the sine wave component calculated by the sine wave component calculation means deviates from the allowable value. Is provided, the power converter can be stopped without a time delay with respect to the variation of the commutation voltage.

The control device for the power converter according to the third aspect of the present invention determines that an accident has occurred in the AC system when the cosine wave component calculated by the cosine wave component calculation means deviates from the allowable value. Is provided, the power converter can be stopped without a time delay with respect to the variation of the commutation voltage.

The control device for a power converter according to the present invention determines that an accident has occurred in the AC system when both the sine wave component and the cosine wave component deviate from the allowable values, and stops the power converter. The provision of the control means makes it possible to stop the power converter without a time delay with respect to the change of the commutation voltage.

The control device for the power converter according to the present invention determines that an accident has occurred in the AC system when the ratio between the sine wave component and the cosine wave component detected by the ratio detecting means deviates from the allowable value. By providing the control means for reducing the control angle of each phase in the power converter, it is possible to reduce the control angle of each phase in the power converter without time delay with respect to the variation of the commutation voltage. Become.

According to a sixth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing a commutation failure based on the ratio detected by the ratio detection means. A control angle selecting means for selecting a control angle having the smallest value among the control angles of each phase is provided, and the control angle of each phase in the power converter is made to match the control angle selected by the control angle selecting means. Therefore, even if the control angle is reduced to prevent commutation failure,
The transmission power can be prevented from decreasing more than necessary.

According to a seventh aspect of the present invention, the control device for a power converter determines a control angle of each phase necessary for preventing a commutation failure based on the ratio detected by the ratio detecting means. By providing a determining means, the control angle of each phase in the power converter to match the control angle determined by the control angle determining means,
As a result, the control angle can be reduced only for the phase where the accident has occurred. As a result, the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

The control device for the power converter according to the present invention determines that an accident has occurred in the AC system when the sine wave component calculated by the sine wave component calculation means deviates from the allowable value. Is provided, the control angle of each phase in the power converter can be reduced without time delay with respect to the change of the commutation voltage.

According to a ninth aspect of the present invention, the control apparatus for a power converter sets a control angle of each phase necessary for preventing a commutation failure based on the sine wave component calculated by the sine wave component calculation means. Control angle selecting means for selecting the control angle having the smallest value among the control angles of the respective phases, so that the control angle of each phase in the power converter matches the control angle selected by the control angle selecting means. By doing so, even if the control angle is reduced in order to prevent commutation failure, it is possible to suppress the transmission power from decreasing more than necessary.

According to a tenth aspect of the present invention, the control device for a power converter sets a control angle of each phase necessary for preventing a commutation failure based on the sine wave component calculated by the sine wave component calculation means. By providing control angle determining means for determining, and by making the control angle of each phase in the power converter coincide with the control angle determined by the control angle determining means, the control angle is determined only for the phase where the accident has occurred. As a result, the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

According to the eleventh aspect of the present invention, the power converter controller determines that an accident has occurred in the AC system when the cosine wave component calculated by the cosine wave component calculation means deviates from the allowable value. Is provided, the control angle of each phase in the power converter can be reduced without time delay with respect to the change of the commutation voltage.

According to a twelfth aspect of the present invention, the control device for a power converter determines a control angle of each phase necessary for preventing commutation failure based on the cosine wave component calculated by the cosine wave component calculation means. Control angle selecting means for selecting the control angle having the smallest value among the control angles of the respective phases, so that the control angle of each phase in the power converter matches the control angle selected by the control angle selecting means. By doing so, even if the control angle is reduced in order to prevent commutation failure, it is possible to suppress the transmission power from decreasing more than necessary.

According to a thirteenth aspect of the present invention, the control device for a power converter sets a control angle of each phase necessary for preventing commutation failure based on the cosine wave component calculated by the cosine wave component calculation means. By providing control angle determining means for determining, and by making the control angle of each phase in the power converter coincide with the control angle determined by the control angle determining means, the control angle is determined only for the phase where the accident has occurred. As a result, the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

According to a fourteenth aspect of the present invention, the control device for a power converter determines that an accident has occurred in the AC system when both the sine wave component and the cosine wave component deviate from the allowable values. Is provided, the control angle of each phase in the power converter can be reduced without time delay with respect to the change of the commutation voltage.

According to a fifteenth aspect of the present invention, the control device for a power converter determines a control angle of each phase necessary for preventing a commutation failure based on a sine wave component and a cosine wave component, and calculates each of the control angles. Control angle selecting means for selecting a control angle having the smallest value among the control angles of the phases is provided, and the control angle of each phase in the power converter is made to match the control angle selected by the control angle selecting means. Accordingly, even if the control angle is reduced in order to prevent commutation failure, it is possible to suppress the transmission power from decreasing more than necessary.

According to a sixteenth aspect of the present invention, a control device for a power converter determines a control angle of each phase necessary for preventing a commutation failure based on a sine wave component and a cosine wave component. Means, and the control angle of each phase in the power converter is made to coincide with the control angle determined by the control angle determining means, so that the control angle can be reduced only for the phase in which an accident has occurred. As a result, the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

[0041]

【Example】

Embodiment 1 FIG. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a control device for a power converter according to a first embodiment of the present invention. 11a, 11b and 11c are sine wave component calculators (sine wave component calculation means) for calculating sine wave components of the commutation voltages detected by the subtractors 5a to 5c, 12a, 12b and 12
c is a cosine wave component calculator (cosine wave component calculation means) for calculating the cosine wave component of the commutation voltage detected by the subtractors 5a to 5c.

Reference numerals 13a, 13b and 13c denote ratio detectors for detecting the ratio between the sine wave components calculated by the sine wave component calculators 11a to 11c and the cosine wave components calculated by the cosine wave component calculators 12a to 12c. (Ratio detection means),
Reference numerals 14a, 14b, and 14c denote accident detectors which determine that an accident has occurred in the AC system 1 when the ratio detected by the ratio detectors 13a to 13c deviates from an allowable value, and is ORed with the accident detectors 14a to 14c. The control means is constituted by the circuit 9 and the controller 10.

Next, the operation will be described. First, in a steady state where no accident occurs in the AC system 1, the reference axis (cosωt, sin
ωt) and the phase of the commutation voltage coincide, and the phase of the commutation voltage hardly deviates from the reference axis, so that the ratio of the sine wave component to the cosine wave component of the commutation voltage becomes substantially constant. However, an accident occurred in the AC system 1 and the AC system 1
Abruptly changes the phase voltage of the commutation voltage from the reference axis specified by the frequency of the AC system 1, so that the ratio of the sine wave component to the cosine wave component of the commutation voltage changes. Become.

Therefore, in the first embodiment, a change in the ratio of the sine wave component to the cosine wave component of the commutation voltage is monitored to detect an accident in the AC system 1. Specifically, similarly to the conventional example, when the subtracters 5a to 5c detect the commutation voltage, the detection results are converted to the sine wave component calculator 11a.
To 11c and cosine wave component calculators 12a to 12c, respectively, and calculate a sine wave component a and a cosine wave component b of the commutation voltage V as described below. a = V · sinωt + (dV / dt) / ω · cosωt (1) b = V · cosωt− (dV / dt) / ω · sinωt (2) where ω is the angle of the AC system 1 Frequency dV / dt is the time derivative of commutation voltage V

When the sine wave component a and the cosine wave component b of the commutation voltage V are calculated in this way, the ratio detectors 13a to 13a
13c is the ratio (a / b) between the sine wave component a and the cosine wave component b
Is detected. Then, the accident detectors 14a to 14c constantly monitor whether the ratio between the sine wave component a and the cosine wave component b detected by the ratio detectors 13a to 13c does not deviate from a predetermined allowable value. Then, the accident detectors 14a to 14
If any one of c detects a deviation from the allowable value, it is determined that an accident has occurred in the phase of the AC system 1 that has deviated, and OR
The circuit 9 outputs an accident detection signal.

When the fault detection signal is output from the OR circuit 9 in this way, the controller 10 stops the operation of the power converter 3 to prevent the commutation failure of the power converter 3, and a series of operations are performed. The process ends.

As described above, according to the first embodiment, the sine wave component a detected by the ratio detectors 13a to 13c
AC system 1 when the ratio of
It is determined that an accident has occurred. Therefore, unlike the conventional example, there is no influence of the time delay due to the phase characteristics of the filters 6a to 6c, and there is no time delay with respect to the variation of the commutation voltage V. In addition, the power converter 3 can be stopped, and there is an effect that the commutation failure of the power converter 3 can be reliably prevented.

Embodiment 2 FIG. In the first embodiment, the ratio detectors 13a to 13c detect the ratio between the sine wave component a and the cosine wave component b, and the accident detectors 14a to 14c monitor the change in the ratio to detect an accident in the AC system 1. However, when an accident occurs in the AC system 1, not only the ratio of the sine wave component a and the cosine wave component b but also the sine wave component a changes, so that as shown in FIG. accident detector (control means) 15a for determining whether a has deviated from the allowable value
By providing ~ 15c, an accident of the AC system 1 may be detected.

According to the second embodiment, the cosine wave component calculators 12a to 12c and the ratio detector 13a in the first embodiment are used.
Since it is possible to detect an accident in the AC system 1 without providing the power converters 13c to 13c, it is possible to construct a power converter control device with a simpler configuration than in the first embodiment.

Embodiment 3 FIG. In the first embodiment, the ratio detectors 13a to 13c detect the ratio between the sine wave component a and the cosine wave component b, and the accident detectors 14a to 14c monitor the change in the ratio to detect an accident in the AC system 1. However, when an accident occurs in the AC system 1, not only the ratio of the sine wave component a to the cosine wave component b but also the cosine wave component b changes, so that as shown in FIG. accident detector (control means) 16a for determining whether or not b has deviated from an allowable value
By providing ~ 16c, an accident of the AC system 1 may be detected. However, when the reference axis is a sine wave, the cosine wave component b of the commutation voltage becomes 0 unless the AC system 1 has an accident, so that the cosine wave component b is no longer 0. Thus, it can be determined that an accident has occurred in the AC system 1.

According to the third embodiment, the sine wave component calculators 11a to 11c and the ratio detector 13a in the first embodiment are used.
Since it is possible to detect an accident in the AC system 1 without providing the power converters 13c to 13c, it is possible to construct a power converter control device with a simpler configuration than in the first embodiment.

Embodiment 4 FIG. In the second and third embodiments, the detection of an accident in the AC system 1 based on a change in either the sine wave component a or the cosine wave component b has been described. However, as shown in FIG. Accident detectors 18a to 18c (control means) for judging that an accident has occurred in AC system 1 when both a and cosine wave component b deviate from the allowable values may be provided. By the way, 17a, 17b, 17c
Is an AND circuit (control means).

According to the fourth embodiment, since changes in both the sine wave component a and the cosine wave component b are monitored, an accident of the AC system 1 can be detected more reliably than in the second and third embodiments. be able to.

Embodiment 5 FIG. In the first to fourth embodiments, the case where the power converter 3 is stopped when an accident of the AC system 1 is detected has been described. However, once the power converter 3 is stopped, the operation of the power converter 3 is restarted. Since it takes a certain amount of time before power transmission starts again, FIGS.
As shown in (1), the control angle required to prevent the commutation failure of the power converter 3 when an accident occurs in the AC system 1 is set in advance by the setting unit 19 (control means) and the OR circuit 9. A switch 20 for switching the input of the power converter 3 from the controller 10 to the setting unit 19 when the accident detection signal is output
(Control means) may be provided to reduce the control angle of each phase in the power converter 3 when an accident occurs in the AC system 1.

More specifically, the setting unit 19
The control angle necessary to prevent the commutation failure of the power converter 3 when an accident occurs in the AC system 1 (from the control angle of the power (Small control angle) is set, and when an accident detection signal is output from the OR circuit 9, the changeover switch 20 switches the input of the power converter 3 from the controller 10 to the setting device 19. Occurs, the power converter 3
Is smaller than in the steady state, and commutation failure of the power converter 3 is prevented.

Therefore, according to the fifth embodiment, when an accident occurs in the AC system 1, not only the commutation failure of the power converter 3 is prevented, but also the power transmission need not be stopped, and Since the power converter 3 is not stopped, there is an effect that the power transmitted before the occurrence of the accident can be immediately transmitted when the accident that occurred in the AC system 1 is restored.

Embodiment 6 FIG. In the fifth embodiment, the AC system 1
In the case where an accident occurs, the control angle of the power converter 3 is made to coincide with the control angle preset in the setting unit 19, but as shown in FIGS. 9 to 12, the sine wave component a and the cosine A control angle determiner (control angle selector) that determines a control angle of each phase necessary to prevent a commutation failure based on the ratio of the wave component b or at least one of the sine wave component a and the cosine wave component b. Means) 21a to 21c and a control angle selector 22 (control angle selecting means) for selecting a control angle having the smallest value among the control angles of each phase determined by the control angle determiners 21a to 21c, When an accident occurs in the AC system 1, the control angle of each phase in the power converter 3 may be matched with the control angle selected by the control angle selector 22.

More specifically, the control angle determiners 21a to 21c determine commutation at the time of the occurrence of an accident according to the ratio of the sine wave component a to the cosine wave component b and the sine wave component a or the cosine wave component b. Since there is a table in which a control angle that can prevent failure is set, when a ratio or the like of the sine wave component a and the cosine wave component b is input, a control angle corresponding to the ratio or the like is extracted from the table. Output.

When the control angle of each phase is output from the control angle determiners 21a to 21c, the control angle selector 22 selects the control angle having the smallest value among the control angles of each phase. The reason for selecting the control angle with the smallest value is that if all phases are controlled together with other control angles, the control angle of the phase in which the accident actually occurred will be sufficiently controlled to prevent commutation failure. This is because commutation failure occurs without being reduced to the corner. In other words, if the control angle with the smallest value is selected, the control angle of the phase in which the accident has not actually occurred is smaller than necessary, but the control angle of the phase in which the accident has actually occurred will cause the commutation failure. This is because the control angle is reduced to a control angle sufficient to prevent the occurrence.

When an accident detection signal is output from the OR circuit 9, the changeover switch 20 switches the input of the power converter 3 from the controller 10 to the control angle selector 22, so that if an accident occurs in the AC system 1, In addition, the control angle of the power converter 3 becomes smaller than that in the steady state, and the commutation failure of the power converter 3 is prevented.

As described above, according to the sixth embodiment, since the control angle is determined according to the ratio of the sine wave component a to the cosine wave component b, the control angle suitable for the state of the AC system 1 is determined. As a result, as in the fifth embodiment,
As compared with the case where the control angle of the power converter 3 is always made equal to the same control angle, there is an effect that the commutation failure can be prevented without reducing the transmission power. That is, in the case of the fifth embodiment,
Since it is necessary to set the control angle at the time of an accident in anticipation of the worst case, the control angle is made smaller than necessary at a relatively small accident, resulting in an extremely large reduction in the transmission power. On the other hand, in the case of the sixth embodiment, since the control angle suitable for the state of the AC system 1 is determined, the reduction of the transmission power does not become larger than necessary.

Embodiment 7 FIG. In the sixth embodiment, the control angle having the smallest value is selected from the control angles of the respective phases determined by the control angle determiners 21a to 21c, and the control angle of the power converter 3 matches the selected control angle. 13 to 16, when the accident detection signal is output from the OR circuit 9, the input of the power converter 3 is switched from the controller 10 to the control angle determiners 21a to 21c, as shown in FIGS. The switches 23a to 23c (control means) are provided so that when an accident occurs in the AC system 1, the control angles of the respective phases in the power converter 3 match the control angles determined by the control angle determiners 21a to 21c, respectively. It may be. In addition,
In the seventh embodiment, the control angle determiners 21a to 21c constitute control angle determining means.

More specifically, in the case of the seventh embodiment, instead of performing the collective control for each phase as in the sixth embodiment, a control angle different for each phase is controlled. That is, when an accident detection signal is output from the OR circuit 9, the changeover switches 23a to 23c switch the input of the power converter 3 from the controller 10 to the control angle determiners 21a to 21c. Then, the control angles determined by the control angle determiners 21a to 21c are input to the power converter 3, and the phases of the power converter 3 match the control angles determined by the control angle determiners 21a to 21c, respectively. Is controlled as follows.

As described above, according to the seventh embodiment, only the control angle of the phase in which an accident actually occurs can be reduced, so that the control angle of the phase in which an accident does not actually occur need not be reduced. Therefore, the transmission power at the time of an accident can be increased more than the sixth embodiment. However, since each phase is individually controlled, the amount of harmonics is larger than in the sixth embodiment.

[0065]

As described above, according to the first aspect of the present invention, if the ratio between the sine wave component and the cosine wave component detected by the ratio detecting means deviates from the allowable value, an accident occurs in the AC system. Judgment is made so that the power converter is stopped, so that the power converter can be stopped without time delay with respect to the fluctuation of the commutation voltage, and the commutation failure of the power converter can be surely prevented. There is an effect that can be prevented.

According to the second aspect of the invention, when the sine wave component calculated by the sine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and the power converter is stopped. With this configuration, the power converter can be stopped without a time delay with respect to the change of the commutation voltage, and there is an effect that the commutation failure of the power converter can be reliably prevented. In addition, since the cosine wave component calculating means and the ratio detecting means are not required, there is an effect that a control device of the power converter can be constructed with a simpler configuration than the invention of claim 1.

According to the third aspect of the invention, when the cosine wave component calculated by the cosine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and the power converter is stopped. With this configuration, the power converter can be stopped without a time delay with respect to the change of the commutation voltage, and there is an effect that the commutation failure of the power converter can be reliably prevented. Further, since the sine wave component calculating means and the ratio detecting means are not required, there is an effect that a control device of the power converter can be constructed with a simpler configuration than the invention of claim 1.

According to the present invention, when both the sine wave component and the cosine wave component deviate from the allowable values, it is determined that an accident has occurred in the AC system, and the power converter is stopped. , The power converter can be stopped without time delay with respect to the fluctuation of the commutation voltage,
There is an effect that the commutation failure of the power converter can be more reliably prevented than the inventions of claims 2 and 3.

According to the fifth aspect of the present invention, when the ratio of the sine wave component to the cosine wave component detected by the ratio detecting means deviates from the allowable value, it is determined that an accident has occurred in the AC system.
Since the control angle of each phase in the power converter is configured to be small, it is possible to reduce the control angle of each phase in the power converter without time delay with respect to the change of the commutation voltage. In addition to preventing commutation failure at the time of occurrence, there is an effect that power transmission can be continued without stopping.

According to the invention of claim 6, based on the ratio detected by the ratio detecting means, the control angle of each phase required to prevent the commutation failure is obtained, and the control angle of each phase is determined. The control angle selecting means for selecting the control angle having the smallest value among the control angles is provided, and the control angle of each phase in the power converter is configured to match the control angle selected by the control angle selecting means. There is an effect that the transmission power can be prevented from being reduced more than necessary while ensuring prevention of failure.

According to the seventh aspect of the present invention, there is provided control angle determining means for determining a control angle of each phase necessary for preventing a commutation failure based on the ratio detected by the ratio detecting means. Since the control angle of each phase in the power converter is configured to match the control angle determined by the control angle determining means, the control angle can be reduced only for the phase in which an accident has occurred. There is an effect that the transmission power can be increased as compared with the case where the control angle is controlled collectively.

According to the present invention, when the sine wave component calculated by the sine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and the control of each phase in the power converter is performed. Because it was configured to make the corner smaller,
The control angle of each phase in the power converter can be reduced without time delay with respect to the fluctuation of the commutation voltage, which not only prevents commutation failure in the event of an accident, but also stops power transmission. Has the effect of being able to continue without In addition, since the cosine wave component calculating means and the ratio detecting means are not required, there is an effect that a control device for the power converter can be constructed with a simpler configuration than the invention of claim 5.

According to the ninth aspect of the invention, based on the sine wave component calculated by the sine wave component calculation means, the control angle of each phase necessary to prevent the commutation failure is determined, and the control angle of each phase is determined. A control angle selecting means for selecting a control angle having the smallest value among the control angles of the phases is provided, and the control angle of each phase in the power converter is made to coincide with the control angle selected by the control angle selecting means. Therefore, there is an effect that the transmission power can be prevented from being reduced more than necessary while ensuring the prevention of the commutation failure.

According to the tenth aspect of the present invention, a control angle determination for determining a control angle of each phase necessary for preventing commutation failure based on the sine wave component calculated by the sine wave component calculation means. Means is provided so that the control angle of each phase in the power converter is made to match the control angle determined by the control angle determining means, so that the control angle can be reduced only for the phase in which an accident has occurred. As a result, there is an effect that the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

According to the eleventh aspect, when the cosine wave component calculated by the cosine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and control of each phase in the power converter is performed. Since the angle is reduced, the control angle of each phase in the power converter can be reduced with no time delay to fluctuations in the commutation voltage, preventing commutation failure in the event of an accident. not only,
There is an effect that power transmission can be continued without stopping. Also,
Since the sine wave component calculating means and the ratio detecting means become unnecessary,
There is also an effect that a control device for a power converter can be constructed with a simpler configuration than the invention of claim 5.

According to the twelfth aspect of the present invention, based on the cosine wave component calculated by the cosine wave component calculation means, the control angle of each phase necessary for preventing the commutation failure is determined, and each of the control angles is determined. A control angle selecting means for selecting a control angle having the smallest value among the control angles of the phases is provided, and the control angle of each phase in the power converter is made to coincide with the control angle selected by the control angle selecting means. Therefore, there is an effect that the transmission power can be prevented from being reduced more than necessary while ensuring the prevention of the commutation failure.

According to the thirteenth aspect of the present invention, the control angle determination for determining the control angle of each phase necessary for preventing the commutation failure based on the cosine wave component calculated by the cosine wave component calculation means. Means is provided so that the control angle of each phase in the power converter is made to match the control angle determined by the control angle determining means, so that the control angle can be reduced only for the phase in which an accident has occurred. As a result, there is an effect that the transmission power can be increased as compared with the case where the control angle is controlled collectively for each phase.

According to the fourteenth aspect, when both the sine wave component and the cosine wave component deviate from the allowable values, it is determined that an accident has occurred in the AC system, and the control angle of each phase in the power converter is reduced. As a result, the control angle of each phase in the power converter can be reduced without time delay with respect to the change of the commutation voltage, and not only prevention of commutation failure at the occurrence of an accident but also This has the effect that power transmission can be continued without stopping.

According to the fifteenth aspect, based on the sine wave component and the cosine wave component, the control angle of each phase required to prevent the commutation failure is determined, and the control angle of each phase is calculated. The control angle selecting means for selecting the control angle having the smallest value is provided, and the control angle of each phase in the power converter is configured to match the control angle selected by the control angle selecting means. It is possible to prevent the transmission power from decreasing more than necessary while ensuring the prevention of the transmission.

According to the sixteenth aspect of the present invention, there is provided control angle determining means for determining a control angle of each phase necessary for preventing a commutation failure based on a sine wave component and a cosine wave component. Since the control angle of each phase in the converter is made to coincide with the control angle determined by the control angle determining means, the control angle can be reduced only for the phase in which an accident has occurred. Thus, there is an effect that the transmission power can be increased as compared with the case where the control angle is controlled by the control.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a control device of a power converter according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram illustrating a control device of a power converter according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a control device of a power converter according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a control device of a power converter according to Embodiment 4 of the present invention.

FIG. 5 is a configuration diagram showing a control device of a power converter according to Embodiment 5 of the present invention.

FIG. 6 is a configuration diagram illustrating a control device of a power converter according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram showing a control device of a power converter according to Embodiment 5 of the present invention.

FIG. 8 is a configuration diagram showing a control device of a power converter according to Embodiment 5 of the present invention.

FIG. 9 is a configuration diagram showing a control device of a power converter according to Embodiment 6 of the present invention.

FIG. 10 is a configuration diagram illustrating a control device for a power converter according to a sixth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a control device of a power converter according to Embodiment 6 of the present invention.

FIG. 12 is a configuration diagram illustrating a control device of a power converter according to a sixth embodiment of the present invention.

FIG. 13 is a configuration diagram showing a control device of a power converter according to Embodiment 7 of the present invention.

FIG. 14 is a configuration diagram showing a control device of a power converter according to Embodiment 7 of the present invention.

FIG. 15 is a configuration diagram illustrating a control device of a power converter according to a seventh embodiment of the present invention.

FIG. 16 is a configuration diagram illustrating a control device of a power converter according to a seventh embodiment of the present invention.

FIG. 17 is a configuration diagram showing a conventional control device for a power converter.

[Description of Signs] 3 power converters, 4a, 4b, 4c AC voltage detectors (commutation voltage detection means), 5a, 5b, 5c subtractors (commutation voltage detection means), 9 OR circuits (control means), 10
Controller (control means), 11a, 11b, 11c Sine wave component calculator (sine wave component calculation means), 12a, 12b,
12c cosine wave component calculator (cosine wave component calculation means), 1
3a, 13b, 13c ratio detector (ratio detecting means),
14a, 14b, 14c, 15a, 15b, 15c, 1
6a, 16b, 16c, 18a, 18b, 18c Accident detector (control means), 17a, 17b, 17c AND
Circuit (control means), 19 setting device (control means), 20,
23a, 23b, 23c switch (control means),
21a, 21b, 21c Control angle determiner (control angle selecting means, control angle determining means), 22 control angle selector (control angle selecting means).

Claims (16)

(57) [Claims] 1. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting a power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculation means, a cosine wave component calculation means for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means, a sine wave component calculated by the sine wave component calculation means, and the cosine wave component A ratio detecting means for detecting a ratio of the cosine wave component calculated by the calculating means; and determining that an accident has occurred in the AC system when the ratio detected by the ratio detecting means deviates from an allowable value, and Control device for controlling the power converter, the control device comprising: 2. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting the power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculating means, and a control means for determining that an accident has occurred in the AC system when the sine wave component calculated by the sine wave component calculating means deviates from the allowable value, and controlling the power converter to stop. Converter control device. 3. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting the power converter, and a cosine wave for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculating means, and a control means for determining that an accident has occurred in the AC system when the cosine wave component calculated by the cosine wave component calculating means deviates from the allowable value, and stopping the power converter. Converter control device. 4. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting the power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculation means, a cosine wave component calculation means for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means, a sine wave component and the cosine wave component calculated by the sine wave component calculation means A control device for a power converter, comprising: control means for determining that an accident has occurred in an AC system when both of the cosine wave components calculated by the calculation means deviate from an allowable value and stopping the power converter. 5. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting a power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculation means, a cosine wave component calculation means for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means, a sine wave component calculated by the sine wave component calculation means, and the cosine wave component A ratio detecting means for detecting a ratio of the cosine wave component calculated by the calculating means; and determining that an accident has occurred in the AC system when the ratio detected by the ratio detecting means deviates from an allowable value, and A control device for reducing the control angle of each phase in the power converter. 6. A control angle of each phase necessary for preventing a commutation failure is determined based on the ratio detected by the ratio detection means, and the control angle of each phase is the smallest. 6. A control angle selecting means for selecting a control angle, wherein the control means makes a control angle of each phase in the power converter coincide with a control angle selected by the control angle selecting means. A control device for the power converter according to claim 1. 7. A control angle determining means for determining a control angle of each phase necessary for preventing a commutation failure based on the ratio detected by the ratio detecting means, wherein the control means comprises: 6. The control device for a power converter according to claim 5, wherein the control angle of each phase in the power converter is made to coincide with the control angle determined by the control angle determining means. 8. A commutation voltage detection means for detecting a commutation voltage of each switching element constituting the power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. When the sine wave component calculated by the component calculation means and the sine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and control for reducing the control angle of each phase in the power converter is performed. Control device for a power converter, comprising: 9. A control angle of each phase necessary for preventing a commutation failure is determined based on the sine wave component calculated by the sine wave component calculation means, and a control angle of each phase is calculated. Control angle selecting means for selecting a control angle having the smallest value is provided, wherein the control means matches a control angle of each phase in the power converter with a control angle selected by the control angle selecting means. The control device for a power converter according to claim 8. 10. A control angle determining means for determining a control angle of each phase necessary for preventing a commutation failure based on the sine wave component calculated by the sine wave component calculating means, 9. The control device for a power converter according to claim 8, wherein the means matches the control angle of each phase in the power converter with the control angle determined by the control angle determining means. 11. A commutation voltage detecting means for detecting a commutation voltage of each switching element constituting the power converter, and a cosine wave for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means. If the cosine wave component calculated by the component calculation means and the cosine wave component calculation means deviates from the allowable value, it is determined that an accident has occurred in the AC system, and control is performed to reduce the control angle of each phase in the power converter. Control device for a power converter, comprising: 12. Based on the cosine wave component calculated by the cosine wave component calculation means, a control angle of each phase necessary for preventing a commutation failure is determined, and among the control angles of each phase, Control angle selecting means for selecting a control angle having the smallest value is provided, wherein the control means matches a control angle of each phase in the power converter with a control angle selected by the control angle selecting means. The control device for a power converter according to claim 11, wherein 13. A control angle determining means for determining a control angle of each phase necessary for preventing a commutation failure based on the cosine wave component calculated by the cosine wave component calculating means, 12. The control device for a power converter according to claim 11, wherein the means matches the control angle of each phase in the power converter with the control angle determined by the control angle determining means. 14. A commutation voltage detecting means for detecting a commutation voltage of each switching element constituting the power converter, and a sine wave for calculating a sine wave component of the commutation voltage detected by the commutation voltage detection means. A component calculation means, a cosine wave component calculation means for calculating a cosine wave component of the commutation voltage detected by the commutation voltage detection means, a sine wave component and the cosine wave component calculated by the sine wave component calculation means When both of the cosine wave components calculated by the calculating means deviate from the allowable values, it is determined that an accident has occurred in the AC system, and control means for reducing the control angle of each phase in the power converter is provided. Control device. 15. Control of each phase necessary for preventing commutation failure based on the sine wave component calculated by the sine wave component calculation means and the cosine wave component calculated by the cosine wave component calculation means. Control angle selecting means for obtaining the angles and selecting the control angle having the smallest value among the control angles of the respective phases, wherein the control means sets the control angle of each phase in the power converter to the control angle selection. 15. The control angle according to claim 14, wherein the control angle is selected by the means.
A control device for the power converter according to claim 1. 16. Control of each phase necessary for preventing commutation failure based on a sine wave component calculated by the sine wave component calculation means and a cosine wave component calculated by the cosine wave component calculation means. A control angle determining means for determining an angle is provided, and the control means makes a control angle of each phase in the power converter coincide with a control angle respectively determined by the control angle determining means. 15. The control device for a power converter according to claim 14.