JP3426986B2 - Frequency conversion system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of a frequency conversion system for interconnecting power systems having different frequencies, such as power supply for Shinkansen, and in particular, it is composed of a self-extinguishing element and AC A parallel type static frequency converter that consists of a voltage-type self-exciting converter that converts DC to AC and a rotary frequency converter that is composed of a synchronous motor and an AC generator and outputs different frequencies. Control of the frequency conversion system.

[0002]

FIG. 31 shows a conventional frequency conversion system. In FIG. 31, 1 is an AC system, 2A to 2D are transformers, 3A and 3B are synchronous motors, 4A and 4B are AC generators, 5 is a transmission line for transmitting the output of the AC generator to a load, and 6
Is a Scott transformer. A train load (not shown) is connected to the secondary side of the Scott transformer.

The system shown in FIG. 31 rotates a synchronous motor at the frequency of the AC system 1 and rotates a generator coaxial with the synchronous motor to generate electric power. Since the frequency is converted, the number of poles is the frequency ratio to be converted. For example, 5 of AC system 1
When it is desired to convert 0 Hz to 60 Hz, the ratio is 5 on the electric motor side and 6 on the generator side. A device for converting a frequency by combining an electric motor and a generator in this way is called a rotary frequency conversion device.

As described above, conventionally, the rotary frequency converters are connected in parallel according to the capacity required on the load side (train),
It constituted the frequency conversion system. On the other hand, in recent years, with the increase in capacity of self-turn-off devices such as gate turn-off thyristors (hereinafter abbreviated as GTO), it has become possible to manufacture large-capacity frequency converters using self-exciting converters.

FIG. 32 shows a frequency conversion system using a self-excited converter. 32, already described in FIG.
The same elements as those are denoted by the same reference numerals, and description thereof is omitted. 7
A and 7B are composed of GTO or the like, and are voltage type self-exciting converters for converting alternating current to direct current and direct current to alternating current, and 8 is a direct current capacitor.

In the system of FIG. 32, the power of the AC system 1 is converted into DC by the voltage type self-excited converter 7A, and the desired frequency is converted by the voltage type self-excited converter 7B connected through the DC capacitor 8. Convert to AC power. Further, when the power is regenerated from the load side, the power is the voltage type self-excited converter 7
It flows from B to the voltage type self-excited converter 7A through the DC capacitor. The general operation of the voltage type self-exciting converter is described in detail in Chapters 6 and 9 of "Semiconductor Power Conversion Circuit" edited by The Institute of Electrical Engineers of Japan.

A frequency conversion device composed of a semiconductor as shown in FIG. 32 is called a static frequency conversion device, and the static frequency conversion device has a loss under no load as compared with a rotary frequency conversion device. There are advantages that the number is small, the start and stop can be performed in a short time, and the output voltage and the output current can be easily controlled.

[0008]

Conventionally, there is no frequency conversion system in which a rotary frequency converter and a static frequency converter are connected in parallel, and different characteristics of the rotary frequency converter and the static frequency converter are provided. There was no control system that was utilized.

The features of the rotating frequency converter, the stationary frequency converter, and the train as a load are shown below. -Rotary frequency converter 1) As shown in Fig. 33, the loss shows a substantially constant value regardless of the load.

2) The time resistance against overload is large. 3) It takes time to start and stop. (10 minutes or more) 4) It is necessary to limit the load when another rotary frequency converter is already started up and an additional rotary frequency converter is added.

Static frequency converter 1) As shown in FIG. 33, the loss varies depending on the load. Especially, the loss at no load is small.

2) There is no time resistance to overload. 3) Start / stop can be performed at high speed. 4) The output voltage and phase can be controlled at high speed.

5) Even if another frequency converter is started up in advance, there is no limit to the additional input.・ Load (train) 1) The reverse current (current with normal 3 phase and reverse rotation phase sequence) is large because it is a single-phase load.

FIG. 34 shows the Scott transformer 6 shown in FIG.
5 shows a waveform when a load is applied to the secondary side of the. FIG. 34 is a waveform when a load of 30 MW is applied to the M seat of the Scott transformer 80 s after 30 MW, and 30 MW is applied to the T seat.
If the load on the T seat is the same, the reverse phase current does not flow, but if there is an imbalance, a reverse phase current is generated.

2) The load constantly changes according to the train schedule and acceleration / deceleration. 3) When the train slows down, active power is regenerated from the train to the power supply. An object of the present invention is to provide a control device for a frequency conversion system in which a rotary type frequency conversion device and a static type frequency conversion device, which have low loss and high reliability, are connected in parallel by making use of the above features. is there.

[0016]

[0017]

[0018]

[Means for Solving the Problems]
Therefore, according to the frequency conversion system of claim 1 of the present invention,
For example, measuring means for measuring the output current of the frequency conversion system
And the anti-phase detector that detects the anti-phase component from the output of the measuring means.
And the level at which the negative-phase component exceeds a certain value
It is equipped with a detection means, and the reverse phase component of the output current exceeds a certain value.
By activating the static frequency converter,
In the region where the reverse phase component of the output current is low,
Only the wave number converter is operated to reduce static load
Stop the wave number converter, and in the area where the negative phase component is large
In addition to the rotary frequency converter,
Operation of the rotary frequency converter
Prevents current overload and protects the entire frequency conversion system.
We can provide a frequency conversion system that can reduce operating loss.
It

According to the frequency conversion system of the second aspect of the present invention, the measuring means for measuring the output current of the frequency converting system, the effective value detecting means for detecting the effective value of each phase of the output of the measuring means, Maximum value selecting means for selecting the maximum value of the effective value of each phase, first level detecting means for detecting that the maximum value of the effective value of each phase exceeds a certain value, and measuring means for measuring the output current. The maximum value of the effective value of each phase of the output current is provided by the anti-phase detecting means for detecting the anti-phase component from the output of the above and the second level detecting means for detecting that the anti-phase component exceeds a certain value. Or, when the anti-phase component exceeds a certain value and the static frequency converter is started, the effective value of each phase of the output current and the anti-phase component are small, so that the rotary frequency converter is not overloaded. Type frequency converter only In the region where the effective value of each phase or the negative phase component is large, the static frequency converter with less load loss is stopped, and the static frequency converter is operated in addition to the rotary frequency converter to operate the rotary frequency converter. It is possible to provide a frequency conversion system capable of preventing a reverse phase current of a device and overload of each phase and reducing an operating loss of the entire frequency conversion system.

According to the frequency conversion system of the third aspect of the present invention, the anti-phase detecting means for detecting the anti-phase component is provided with a means for detecting an average value of the detected values at a constant time. The static frequency converter can be started and stopped in accordance with the time resistance of the rotary frequency converter, so even if there are frequent load fluctuations near the start determination level of the static frequency converter, unnecessary static It is possible to provide a frequency conversion system in which the activation of the frequency conversion device can be suppressed and the disturbance is reduced.

According to the frequency conversion system of the fourth aspect of the present invention, by providing each level detecting means with a hysteresis characteristic, it is possible to prevent the reverse phase current of the rotary frequency conversion device and the overload of each phase. In addition, it is possible to provide a frequency conversion system that can prevent unnecessary start and stop of the static frequency conversion device and reduce the operating loss of the entire frequency conversion system.

[0022]

[0023]

[0024]

[0025]

According to the frequency conversion system of the fifth aspect of the present invention, the output current after the start of the static frequency conversion device is increased.
The reference is converted to the output current of the frequency conversion system.
Rotation frequency from the reverse phase current included in the output current of the stem
The allowable negative-phase current of the converter is subtracted, and the value is frequency converted.
By multiplying the value by dividing the value by dividing by the system reverse phase current, the rotating frequency converter that has almost constant loss regardless of the output current after starting the static frequency converter can be used for the rated current of the reverse phase current. A frequency conversion system that can be operated at the same time and the rest will be shared by the static frequency conversion device, reducing the operating loss of the entire frequency conversion system and preventing overload due to the reverse phase component of the rotary frequency conversion device. it can.

[0027]

According to the sixth aspect of the present invention, the frequency conversion system includes the output current of the frequency conversion system.
Equipped with anti-phase current detection means to detect anti-phase component, static type
The output current reference after starting the frequency conversion device is
From the negative phase current of the frequency conversion system to the output of the flow detection means
The value obtained by subtracting the rated reverse-phase current of the rotary frequency converter
Is divided by the negative phase current of the frequency conversion system and multiplied by
With this value , after starting the static frequency converter, the rotary frequency converter, which has almost constant loss regardless of the output current, is operated at the rated current of the negative phase current and the rest of the negative phase current is stopped. It will be shared by the frequency converter
The operating loss of the entire frequency conversion system can be reduced, and
It is possible to provide a frequency conversion system capable of preventing overload due to a reverse phase component of a rotary frequency conversion device.

[0029]

[0030]

[0031]

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a first embodiment of the present invention. In FIG. 1, FIG. 31 and FIG.
The same elements as those of 2 are given the same reference numerals and the description thereof will be omitted.

In FIG. 1, an AC current detector 9 for measuring an output current is provided on the output side of a frequency conversion system in which a rotary frequency converter and a static frequency converter are connected in parallel.
The three-phase full-wave rectifier 10 full-wave rectifies the three-phase alternating current from the alternating current detector 9.

The level setter 11 sets the level at which the static frequency converter is activated, and the level detector 12 compares the output of the three-phase full-wave rectifier 10 with the output of the level setter 11 to determine the level of the three-phase full-wave rectifier. When the output of 10 is large, the start command 51 of the static frequency converter is output.

The circuit shown in FIG. 1 operates as follows.
There is a train load (not shown) on the secondary side of the Scott transformer 6 in FIG. 1, and it constantly fluctuates according to the train schedule and the acceleration / deceleration pattern. The load current is detected by the output current detector 9, which is rectified by a three-phase full-wave rectifier to obtain a direct current amount, and the level detector 12 compares it with the output of the level setter 11.

When the train load increases, the load current increases, the output of the three-phase full-wave rectifier 10 increases, and when the level setting value is exceeded, a start command is issued to the static frequency converter. When the train load is small and the output of the three-phase full-wave rectifier 10 does not exceed the level setting value, the static frequency converter is stopped.

As described above, when the static frequency converter is started and stopped by the circuit shown in FIG. 1, when the train load is low, the rotary frequency converter with less fluctuation in loss due to the load is operated and no load is applied. Since the static frequency converter with less loss is stopped, the loss of the entire frequency conversion system can be reduced.

Next, a second embodiment of the present invention will be described. FIG. 2 is a configuration diagram of the second embodiment of the present invention. 2, the same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 2, effective value calculation circuits 13A to 13A are provided.
3C inputs the current of each phase of the output current detector 9, calculates the effective value of each, and the maximum value selection circuit 14 inputs the outputs of the effective value calculation circuits 13A to 13C and selects the maximum value. The output of the maximum value selection circuit 14 becomes one input of the level detector 12.

The circuit shown in FIG. 2 operates as follows.
When the train load increases, the load current increases, the effective value of each phase increases, and when the output of the maximum value selection circuit 14 exceeds the level set value, a start command is issued to the static frequency converter. When the train load is low and the maximum effective value of each phase does not exceed the level setting value, the static frequency converter stops.

By detecting the effective value for each phase, for example, even when the amount of reverse phase is large and the output current of each phase is unbalanced, the stationary frequency converter is started by the phase with the heaviest load. Since the stop is determined, overload of the rotary frequency converter can be prevented.

As described above, when the static frequency converter is started and stopped in the circuit shown in FIG. 2, when the train load is low, the rotating rod frequency converter with less fluctuation in loss due to the load is operated, Since the static frequency conversion device, which has a small loss under no load, is stopped, the loss of the entire frequency conversion system can be reduced.

As shown in FIG. 3, level detectors 12A to 12C are provided for each phase after the effective value arithmetic circuits 13A to 13C for each phase, and the outputs of the level detectors 12A to 12C are ORed. It is obvious that the same effect can be obtained by inputting the signal to the circuit 15 and starting the static frequency converter with the output thereof.

Next, a third embodiment of the present invention will be described. FIG. 4 is a configuration diagram of the third embodiment of the present invention. 4, the same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 4, the anti-phase detection circuit 16 inputs the output of the alternating current detector 9 and detects the anti-phase component. The output of the anti-phase detection circuit 16 becomes one input of the level detector 12.

The circuit shown in FIG. 4 operates as follows.
When the load on the M and T seats of the output of the Scott transformer 6 becomes unbalanced, the anti-phase component of the output current increases. For example, in FIG. 5, a power load of 30 MW is applied to the Scott transformer M seat,
The waveform of each part when a regenerative load of 30 MW is applied to the T seat 80 ms after that is shown. At this time, the reverse phase component is the largest when the power running and the regeneration are applied to different seats, and in FIG. 5, the reverse phase component is about 60 MVA, and the current is almost only the reverse phase component.

On the other hand, the rotary frequency converter has a limit for the amount of reverse phase that can be flowed, and if it exceeds a certain value, the reverse phase relay or the like may operate and trip. Therefore, if the frequency conversion system is controlled by a circuit as shown in FIG. 4, when the antiphase component of the train load increases, the output to the antiphase detector 16 increases, and when the level setting value is exceeded, the static frequency A start command 51 is issued to the converter, the static frequency converter shares a part of the negative phase component, and the negative phase component of the rotary frequency converter can be reduced. Trips can be prevented.

Next, a fourth embodiment of the present invention will be described. FIG. 6 is a configuration diagram of the fourth embodiment of the present invention. 6, the same elements as those in FIGS. 2 and 4 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 6, a logical sum circuit 15 takes the logical sum of the output of the level detector 12A based on the effective value calculation circuit and the output of the level detector 12B based on the anti-phase detection circuit, and stands still. It is output as a start command 51 of the frequency converter.

The circuit shown in FIG. 6 operates as follows.
When the train load increases, the load current increases, the outputs of the effective value calculation circuits 13A to 13C for each phase increase, and at the time when the output of the maximum value selection circuit 14 exceeds the level set value 11A,
A start command is issued to the static frequency converter. Even if the maximum value of the effective value of each phase current does not reach the level setting value 11A, if the reverse phase setting value 11B is exceeded in the operation with a large reverse phase current such as one-sided power running and one-sided regenerative operation, the system remains stationary. A start command is issued to the frequency converter.

In this way, the effective value for each phase and the opposite phase component of the rotary frequency converter can be set differently, and the static frequency converter is started when either of them exceeds the tolerance of the rotary frequency converter. Therefore, more reliable control is possible.

Next explained is the fifth embodiment of the invention. FIG. 7 is a configuration diagram of the fifth embodiment of the present invention. 7, the same elements as those of FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 7, effective value calculation circuits 13A to 13A
3C and the time average calculation circuit 1 on the output side of the negative phase detection circuit 16
7A to 17D are connected. Time average calculation circuit 17A-
17D calculates the average value of each input within a fixed time.

The circuit shown in FIG. 7 operates as follows.
As described above, the rotary frequency converter has the withstand capability of the effective current of each phase and the withstand amount of the opposite phase, but has a longer withstand time compared with the static frequency converter composed of semiconductors. . In other words, if it exceeds a certain level, it is not instantaneously damaged by overload, and it can withstand a certain period of time.

Therefore, as shown in FIG. 7, after the output of each of the phase effective value calculation circuits 13A to 13C and the output of the anti-phase detection circuit 16, the time corresponding to the time tolerance of the rotary frequency converter is set. An averaging circuit is provided, and its output determines the starting condition of the static frequency converter.

As a result, since the static frequency converter does not respond to an instantaneous load change as compared with the case where the static frequency converter is activated only by the level, the number of times the static frequency converter is activated and stopped can be reduced, and the static frequency converter is reduced. It is possible to reduce the number of disturbances caused by the start and stop of the converter.

Note that, as shown in FIG. 8, the same effect can be obtained by providing a time averaging arithmetic circuit in the subsequent stage of the maximum value selecting circuit 14 in order to simplify the circuit. Further, the time averaging circuit of FIGS. 7 and 8 can obtain substantially the same effect as a simple on-delay circuit.

Further, as shown in FIG.
Even if the on-delay circuit 18 is provided in the subsequent stage, almost the same effect can be obtained. Note that the description has been given in the case of being applied to the fourth embodiment, but it goes without saying that the same can be applied to the first to third embodiments.

Next, a sixth embodiment of the present invention will be described. FIG. 10 is a configuration diagram of the sixth embodiment of the present invention. 10, the same elements as those of FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 10, the level detectors are level detectors 19A to 19B with hysteresis characteristics, and the level setting devices 11A to 11D determine the hysteresis characteristics.
The operation of the circuit shown in FIG. 10 is shown in FIG. Waveform A is a start / stop command when a level detector having no hysteresis characteristic is used. If the output of the anti-phase detection circuit 16 or the maximum value detection circuit 14 fluctuates frequently in the vicinity of the detection level A, the static type frequency conversion device start-up command frequently comes and goes.

On the other hand, in the case of the level detector with hysteresis characteristic, the start command is output at the upper level B1 and the start command is canceled at the lower level B2, so the start / stop command becomes the waveform B, and the static frequency conversion is performed. The number of times of starting and stopping the device can be reduced, and the number of disturbances caused by starting and stopping of the static frequency converter can be reduced.

Although the description has been given for the case of being applied to the fourth embodiment, it goes without saying that the same can be applied to the first to third embodiments. Next, a seventh embodiment of the invention will be described.

The seventh embodiment describes a method of determining the set value of the level setter. here,
The operation when applied to the second embodiment will be described with reference to FIG. 12, the solid line represents the output of the maximum value detection circuit 14 in FIG. 2, the dotted line represents the set value of the level setter 11, level 1 represents the rating of the rotary frequency converter, and level 2 represents a lower value.

If the output of the level setter 11 is set to level 1, the static frequency converter is started after the rotary frequency converter exceeds the rating, so the total time during which the static frequency converter is running is Becomes shorter than the set value of level 2.

The relationship between the output and the loss of the rotary frequency converter and the static frequency converter is almost constant loss regardless of the output as shown in FIG. And the case of level 2 are the same loss. On the other hand, since the loss of the static frequency converter increases with the output, the level 2 having a long startup time of the static frequency converter is larger.

Therefore, by setting the level setter to the rated value or the continuous overload rated value of the rotary frequency converter so that the rotary frequency converter is used as much as possible, a frequency conversion system with less loss is provided. it can.

Although the description has been given for the case of being applied to the second embodiment, it goes without saying that the same can be applied to the first, third and fourth embodiments. Next, the eighth aspect of the present invention
The embodiment will be described.

FIG. 13 is an explanatory diagram of the startup sequence of the eighth embodiment of the present invention, and FIG. 14 is a configuration diagram of a frequency conversion system using a self-excited converter. 14, the same elements as those of FIG. 32 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 14, a circuit breaker 20 for connecting the voltage type self-exciting converter to the system is provided, and an initial charging circuit 21 for initially charging the DC capacitor. Figure 1
Sequence A of No. 3 shows an example of a starting sequence of a general voltage type self-exciting converter.

First, when a DC capacitor charging command is given, the initial charging circuit 21 is turned on to charge the DC capacitor. When the DC capacitor is charged to a certain level, the circuit breaker 20 is turned on, the gate is given to the voltage type self-exciting converter, and the operation is started. The circuit breaker may be turned on after starting the voltage type self-exciting converter. When stopped, the gate of the self-excited converter is stopped and the breaker is opened. After stopping
The voltage of the DC capacitor is discharged by a resistance component such as a voltage dividing resistor between the DC bus lines.

Charging of the DC capacitor is generally performed for several tens of seconds to several minutes in order to reduce the capacity of the initial charging circuit. Therefore, in the conventional sequence, it takes a long time to perform the initial charging, and the static frequency conversion device cannot be activated at a high speed when the load suddenly changes.

Sequence B in FIG. 13 is a start / stop sequence according to the eighth embodiment. After charging the DC capacitor once when starting the entire system, the DC capacitor is not discharged and the rated DC voltage is not discharged even if the static frequency converter is not started with a small load as described in the previous embodiment. Maintain a value close to. As a result, the load increases, and the charging operation of the DC capacitor can be omitted when the next start command is received, so that the start time can be shortened.

To maintain the voltage of the DC capacitor, the charging circuit is always connected, or when the DC voltage is lower than the rated voltage by a certain value or more, the self-exciting converter is operated (gate deblocking) and the AC voltage is changed. Use a method such as charging from the grid.

Next, a ninth embodiment of the present invention will be described. FIG. 15 is a general control block diagram of the voltage type self-exciting converter, and FIG. 16 is a control block diagram of the ninth embodiment of the present invention. 16, the same elements as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 15, 9A is an alternating current detector,
Reference numeral 22 is an AC voltage detector, 23 is a current detected by the AC current detector 9A, and the AC voltage detector 22 performs three-phase to two-phase conversion and stationary-rotation coordinate conversion to perform an effective current component (Id) 52.
And a coordinate conversion circuit for detecting the reactive current component (Iq) 53,
24 is a host controller that gives an active current command value (Idref) 53 and a reactive current command value (Iqref) 54; 25 is a difference between the active current command value 53 and the active current component 52; and the reactive current command value 54 and the reactive current component. A constant current control circuit that inputs the difference of 53 and operates so that the difference becomes zero, 26 inputs the effective component output command value 56 and the invalid component output command value 57,
Rotation stationary coordinate conversion, 2-phase to 3-phase coordinate conversion to convert to a three-phase AC output command value, a coordinate inverse conversion circuit, 27 is a self-excited converter from the three-phase AC output command value output from the coordinate inverse conversion circuit. It is a pulse width modulation circuit that creates a pulse pattern for turning on and off 7A.

The control principle of active power and reactive power of the voltage type self-excited converter connected to the AC system is disclosed in "Semiconductor Power Conversion Circuit" (edited by The Institute of Electrical Engineers of Japan), P215-P220, etc. Omit it. Further, the principle and implementation method of the constant current control circuit are also disclosed in JP-A-1-77110.
The detailed description is omitted because it is disclosed in Japanese Patent Publication No.

In FIG. 15, a voltage type self-exciting converter 7A
Performs high-speed constant current control so that the output current matches the active current reference and reactive current reference given by the host control system. Generally, a voltage type self-exciting converter that is connected to an AC voltage source such as an AC system performs constant current control of output current. Note that, as a constant current control method, in FIG. 15, the current is coordinate-converted to be separated into an active current component and a reactive current component, but a three-phase instantaneous value command (sinusoidal waveform) is used.
On the other hand, the current may be controlled by feeding back the three-phase instantaneous value current.

FIG. 16 is a diagram showing a control block according to the ninth embodiment of the present invention. In FIG. 16, reference numeral 23B represents three-phase to two-phase conversion and stationary rotation coordinate conversion from the output current of the frequency conversion system detected by the AC current detector 9 and the output voltage of the frequency conversion system detected by the AC voltage detector 22. Effective output current effective component 58, output current ineffective component 59
Coordinate conversion circuit for detecting the
8. A gain adjuster that applies a gain of 1 or less to the output current reactive component 57 to calculate the current reference of the static frequency converter. Reference numeral 29 is a logical product circuit that obtains the logical product of the gate pattern given to the static frequency converter and the start command.

Since the rotary frequency converter operates as a voltage source, it can have the same configuration as the control circuit of the system-excited self-exciting converter shown in FIG. Although the control circuit on the side of the self-excited converter 7A is not shown in FIG.
It is controlled by the circuit shown in FIG.
It has a reactive power constant control and a DC capacitor voltage constant control, and constant current control is performed based on the reactive current command value and active current command value output from each.

The operation of the ninth embodiment will be described. When the load increases and the static frequency converter start command 51 is output from the level detector 12, the AND circuit 29
Is used to start the operation of the static frequency conversion device.

At this time, the value obtained by multiplying the output current of the entire frequency conversion system by a constant ratio is used as the current reference of the static frequency conversion device, so that the rotary frequency is converted by the ratio shared by the static frequency conversion device. The shared current of the converter can be reduced, and overload of the rotary frequency converter can be prevented.

Further, since the output current of the entire frequency conversion system is detected and used as the current reference, the operation of switching the current reference by detecting and determining the load state is performed even when the load changes or when the load changes from power running to regeneration. It is possible to provide a control device that does not need to be performed and that does not waste.

In FIG. 16, the coordinate conversion circuits 23A and 23B, and the coordinate reverse conversion circuit 26 are provided so that the effective current component,
Controlled for each reactive current component, but without coordinate conversion,
The same effect can be obtained by calculating the three-phase instantaneous value.

Although the description has been given for the case where it is applied to the first embodiment, it goes without saying that it can be similarly applied to the second to fourth embodiments. Next, a tenth embodiment of the present invention will be described.

The tenth embodiment of the present invention defines the calculation method of the gain adjusting circuit of the ninth embodiment. FIG. 17 is a diagram showing a calculation method of the gain adjuster 28.

First, the output current effective component (Idout) 5
8 and the output current reactive component (Iqout) 59, the magnitude of the output current (Iout) is obtained. Next, Iout,
And Idout, lqout, an active current command value (Idref) 54 and a reactive current command value (Iqref) 55 of the static frequency converter are obtained.

As described above, the operation of the active current command value and the reactive current command of the static frequency converter is performed as shown in FIG. This is equivalent to sharing the excess of the rated value with the static frequency converter.

When the current reference of the static frequency converter is determined by this method, as described in the seventh embodiment,
It is more effective to combine the detection level of the output current for starting the static frequency converter with the rated current of the rotary frequency converter.

That is, when the output current exceeds the rating of the rotary frequency converter, the static frequency converter is activated, and the current reference of the static frequency converter at that time is the amount that exceeds the rating of the rotary frequency converter. Because it is given as.

Next, an eleventh embodiment of the present invention will be described. FIG. 19 is a configuration diagram of the eleventh embodiment of the present invention, and FIG. 20 is a diagram showing a calculation method of the gain adjuster. In FIGS. 14 and 20, FIGS.
The same symbols are attached to the same elements as, and the description is omitted.

In the gain adjuster 28, the reverse phase detection circuit 16
Output current anti-phase component (INout) 60 which is the output of the rotary frequency converter, anti-phase allowable value (INR) of the rotary frequency converter, output current effective component (Idout) 58, and output current ineffective component (Iq).
out) 59, the active current command value (Idref) 54 and the reactive current command value (Iqre) of the static frequency converter.
f) 55 is calculated by the equation shown in FIG.

In this way, the load is unbalanced and the reverse-phase current increases, and the reverse-phase allowable value (IN
If R is exceeded, the static frequency converter will share the negative-phase current in accordance with the ratio, and it is possible to prevent the rotary frequency converter from tripping with a negative-phase relay or the like.

The present invention is carried out in combination with the third and fourth embodiments of the present invention, and when the output negative-phase current exceeds a certain value, the static frequency converter is activated, When the current reference of the static frequency converter is given by the formula shown in FIG. 20, the loss is small, and the reverse phase component of the rotary frequency converter can be set to the allowable value or less.

21 to 23 show analysis waveforms when controlled by the method of the eleventh embodiment. 30 MV for load
The anti-phase component of A (0.6 pu: 1 pu = 50 MVA) is taken, and the anti-phase allowable value (INR value in FIG. 20) of the rotary frequency converter is changed to carry out three cases.

In FIG. 21, the reverse phase tolerance is 1. lpu (= 5
5 MVA) is shown. Since the anti-phase component of the load does not reach the anti-phase allowable value, the static frequency converter does not share the load, but the anti-phase component of the load directly shares the anti-phase component of the load.

FIG. 22 shows a case where the reverse-phase allowable value is set to 0.4 pu. The anti-phase component of the load is 0.6 pu, which is the same as in the case of FIG. 21, but the static frequency converter shares the anti-phase component, and the anti-phase component of the rotary frequency converter is 0.4.
It has dropped to pu.

FIG. 23 shows a case where the reverse-phase allowable value is set to 0.2 pu. At this time, compared to FIG.
The share of the static frequency converter is increasing, and the reverse phase component of the rotating frequency converter is decreasing.

As can be seen from these analysis waveforms, if the current reference of the static frequency converter is determined according to the present invention, the anti-phase current of the rotary frequency converter can be reduced, and the value can be reduced depending on the set value. Can be controlled.

Next, a twelfth embodiment of the present invention will be described. FIG. 24 is a configuration diagram of the twelfth embodiment of the present invention. 24, the same elements as those of FIG. 19 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 24, the anti-phase component extraction circuit 30 is
Only the opposite phase components are extracted from the output current effective component (Idout) 58 and the output current ineffective component (Iqout) 59, and the output current antiphase effective component 61 and the output current antiphase ineffective component 62 are output.

It is generally known that three-phase alternating current can be separated into a negative phase component, a positive phase component, and a zero phase component. Further, it is possible to separate the effective component and the ineffective component from the phase relationship between the voltage and the current.
Assuming that the zero-phase component is sufficiently small, the three-phase alternating current can be decomposed into the following.

[0102]

## EQU00001 ## Three-phase AC current = positive-phase active current component + positive-phase reactive current component + negative-phase active current component -10-negative-phase reactive current component (Equation 1) The phase active current component and the anti-phase reactive current component are extracted.

Then, the gain adjuster 28 multiplies the component by an appropriate ratio to make it the output current reference of the static frequency converter, and if the antiphase component is supplied from the static frequency converter, the rotary frequency converter is obtained. The reverse phase component of can be reduced.

The difference between the eleventh embodiment and the twelfth embodiment is that the eleventh embodiment uses the value obtained by multiplying the entire output current by a constant ratio as the output current reference of the static frequency converter. As a result, the static frequency conversion device shares both the positive phase component and the negative phase component, whereas the twelfth embodiment of the present invention is that the static frequency conversion device shares only the negative phase component. .

Next, a thirteenth embodiment of the present invention will be described. The thirteenth embodiment of the present invention defines the calculation method of the gain adjustment circuit of the twelfth embodiment.

FIG. 25 is a diagram showing a calculation method of the gain adjuster. In the gain adjuster 28, the reverse phase detection circuit 16
Output current reverse use component (Inout) 60 which is the output of the rotary frequency converter, reverse phase allowable value (INR) of the rotary frequency converter, output current reverse phase effective component (IdN) 58, and output current reverse phase ineffective component (IqN) From 59, the active current command value (Idref) and the reactive current command value (Iqref) of the static frequency converter
Is calculated by the equation shown in FIG.

In this way, when the load is unbalanced and the reverse-phase current increases, and the reverse-phase allowable value of the rotary frequency converter is exceeded, the static frequency converter according to the exceeded ratio. Will share the negative-phase current, and the rotary frequency converter can be prevented from tripping due to the negative-phase relay or the like.

Next, a fourteenth embodiment of the present invention will be described. FIG. 26 is a configuration diagram of the fourteenth embodiment of the present invention, and FIG. 27 is a diagram showing an example of load fluctuation and the number of operating static frequency converters. 26, the same elements as those of FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 26 is an example in which two static frequency converters are connected. In FIG. 26, the static frequency converter 101A is the output 51A of the level detector 12A.
The static frequency converter 101B is activated by 51B which is the output of the level detector 12B.

With the configuration shown in FIG. 26, the level setter 1
Depending on the set values of 1A and the level setter 11B, it is possible to select both of the two static frequency converters to stop, one side to operate, both to operate, and the number of operating machines according to the load.

FIG. 27 is a diagram showing an example of load fluctuations and the number of operating static frequency converters when the circuit shown in FIG. 26 is applied. Until the load reaches level 11A, only the rotary frequency converter is operated, and the load is level 1
Between 1A and 11B, one static frequency converter is operated, and when the load is level 11B or higher, two are operated.

By doing so, in a system having a plurality of static frequency converters, as many level detectors as the number of static frequency converters are provided as shown in FIGS.
If each detection level is made different and the operation stop is determined for each device, it is possible to provide the control device of the frequency conversion device that can minimize the loss in the entire system.

Although the description has been made in the case of being applied to the second embodiment, it goes without saying that the same can be applied to the first, third and fourth embodiments. Next, the first of the present invention
The fifth embodiment will be described.

FIG. 28 is a block diagram of the fifteenth embodiment of the present invention. 28, the same elements as those of FIG. 16 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 28, the limiter circuit 31 limits the active current reference 54 and the reactive current reference 55 output from the gain adjuster 28.

The static frequency converter is, as described above,
It is characterized by a relatively short time tolerance against overload. Therefore, even when the load fluctuation causes a transient overload, a limiter is applied so that the active current reference 54 and the reactive current reference 55 output from the gain adjuster 28 do not exceed the ratings of the static frequency converter.

At this time, the load that cannot be shared by the static frequency converter due to the limiter is supplied from the rotary frequency converter. The rotary frequency converter has a time resistance against overload as compared with the static frequency converter, and there is no problem if the time is short.

FIG. 29 is a block diagram showing a combination of the tenth, eleventh and fifteenth embodiments of the present invention. In FIG. 29, the output current effective component (Idout) 58 and the output current ineffective component (Iqou)
t) 59 is input to the gain adjusters 28A and 28B.

In the gain adjuster 28A, the calculation shown in FIG. 17 is performed, and the static current converter active current reference 54
A and the reactive current reference 55A are output. In the queen adjuster 28B, the static frequency converter active current reference 54B and the reactive current reference 5 are calculated by performing the calculation shown in FIG.
Output 5B.

These references are input to the maximum value selection circuit 14A, and the larger value is used as the current reference of the static frequency converter. However, a limiter 31 is provided so that the rating of the static frequency converter is not exceeded.

With the configuration shown in FIG. 27, the larger value of the negative phase component or the effective current is used as the current reference of the static frequency converter, so that the output of the rotary frequency converter is changed even if the load is largely changed. Is maintained at an appropriate value.

Next, a sixteenth embodiment of the present invention will be described. FIG. 30 is a configuration diagram of the sixteenth embodiment of the present invention. 30, the same elements as those of FIG. 26 are designated by the same reference numerals, and the description thereof will be omitted.

When one or more rotary frequency converters are already in operation and another rotary frequency converter is additionally connected in parallel, the rotation during operation is preceded in order to prevent conduction current and disturbance. It is necessary to set the load of the frequency converter to a constant value (referred to as additional parallel-allowable current) or less.

Since the static frequency converter can control the output current according to the current reference, when the rotary frequency converter is additionally connected, the output current of the rotating frequency converter in operation is additionally parallelized. The static frequency conversion device may share the current so that it is equal to or less than the allowable current.

In FIG. 30, the value set by the level setter 11C is subtracted from the output current of the frequency conversion system detected by the AC current detector 9, and the value is given as the current reference of the static frequency converter. As a result, the shared current of the rotary frequency converter does not exceed the value of the level setter 11C.

However, as described in the fifteenth embodiment, the rating (continuous overload withstanding) of the static frequency converter is provided.
A current reference limiter 31 of the static frequency converter is provided at the final stage so as not to serve as the above current reference.

As described above, the loss at no load is less in the static frequency converter as compared with the rotary frequency converter, so it is not necessary to use the current reference shown in FIG. 29 during continuous operation. During the continuous operation, the static frequency converter is operated with any of the current references described in the ninth to thirteenth embodiments of the present invention, and the additional notice signal for the rotary frequency converter is added. When receiving, the current reference of the static frequency converter is switched as shown in FIG.
After the parallel insertion is completed, if the original current reference is restored, if the operation is performed, the loss during steady operation can be reduced, and the rotary frequency conversion device control device for the frequency conversion system that can be easily operated during parallel insertion Can be provided.

[0127]

[0128]

[0129]

As described above, according to the first aspect of the present invention.
According to the frequency conversion system of
Measuring means for measuring the output current of the
The anti-phase detection means that detects the anti-phase component from the
And a level detecting means for detecting that the value is exceeded,
When the anti-phase component of the output current exceeds a certain value, the static frequency
By activating the number conversion device, the reverse phase component of the output current
Operates only the rotary frequency converter in the low range
Then, stop the static frequency converter with little no-load loss,
In the region where the anti-phase component is large, the rotary frequency converter
In addition to operating the static frequency converter,
Prevents overload of the reverse phase current of the rotary frequency converter
And reduce the operating loss of the entire frequency conversion system.
It is possible to provide a frequency conversion system.

According to the frequency conversion system of the second aspect of the present invention, the measuring means for measuring the output current of the frequency converting system, the effective value detecting means for detecting the effective value of each phase of the output of the measuring means, Maximum value selecting means for selecting the maximum value of the effective value of each phase, first level detecting means for detecting that the maximum value of the effective value of each phase exceeds a certain value, and measuring means for measuring the output current. And a second level detecting means for detecting that the negative phase component exceeds a certain value, and the maximum value of the effective value of each phase of the output current. Or, when the anti-phase component exceeds a certain value and the static frequency converter is started, the effective value of each phase of the output current and the anti-phase component are small, so that the rotary frequency converter is not overloaded. Type frequency converter only In the region where the effective value of each phase or the anti-phase component is large, the static frequency converter with a small load loss is stopped, and the static frequency converter is operated in addition to the rotary frequency converter to operate the rotary frequency converter. It is possible to provide a frequency conversion system capable of preventing a reverse phase current of a device and overload of each phase and reducing an operating loss of the entire frequency conversion system.

According to the frequency conversion system of the third aspect of the present invention, the anti-phase detecting means for detecting the anti-phase component is provided with a means for detecting the average value of the detected values in a certain time. The static frequency converter can be started and stopped in accordance with the time resistance of the rotary frequency converter, so even if there are frequent load fluctuations near the start determination level of the static frequency converter, unnecessary static It is possible to provide a frequency conversion system in which the activation of the frequency conversion device can be suppressed and the disturbance is reduced.

According to the frequency conversion system of the fourth aspect of the present invention, by providing each level detecting means with a hysteresis characteristic, it is possible to prevent the reverse phase current of the rotary frequency conversion device and the overload of each phase. In addition, it is possible to provide a frequency conversion system that can prevent unnecessary start and stop of the static frequency conversion device and reduce the operating loss of the entire frequency conversion system.

[0133]

[0134]

[0135]

[0136]

According to the frequency conversion system of the fifth aspect of the present invention, the output current of the static frequency conversion device after being activated.
The reference is converted to the output current of the frequency conversion system.
Rotation frequency from the reverse phase current included in the output current of the stem
The allowable negative-phase current of the converter is subtracted, and the value is frequency converted.
The value obtained by multiplying the value obtained by dividing by the system negative-phase current allows the rotary frequency converter that has almost constant loss regardless of the output current after starting the static frequency converter to make the rated current of the negative-phase current The frequency conversion system can be operated with the static frequency converter, and the rest is shared by the static frequency converter, which reduces the operating loss of the entire frequency conversion system and prevents overload due to the reverse phase of the rotary frequency converter. it can.

[0138]

According to the frequency conversion system of the sixth aspect of the present invention, it is included in the output current of the frequency conversion system.
Equipped with anti-phase current detection means to detect anti-phase component, static type
The output current reference after starting the frequency conversion device is
From the negative phase current of the frequency conversion system to the output of the flow detection means
The value obtained by subtracting the rated reverse-phase current of the rotary frequency converter
Is divided by the negative phase current of the frequency conversion system and multiplied by
With this value , after starting the static frequency converter, the rotary frequency converter, which has almost constant loss regardless of the output current, is operated at the rated current of the negative phase current and the rest of the negative phase current is stopped. It will be shared by the frequency converter
The operating loss of the entire frequency conversion system can be reduced, and
It is possible to provide a frequency conversion system capable of preventing overload due to a reverse phase component of a rotary frequency conversion device.

[0140]

[0141]

[0142]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a diagram showing another configuration of the second embodiment of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the third embodiment of the present invention.

FIG. 6 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a fifth embodiment of the present invention.

FIG. 8 is a diagram showing another configuration of the fifth embodiment of the present invention.

FIG. 9 is a diagram showing another configuration of the fifth embodiment of the present invention.

FIG. 10 is a configuration diagram of a sixth embodiment of the present invention.

FIG. 11 is an operation explanatory diagram of the sixth embodiment of the present invention.

FIG. 12 is an operation explanatory diagram of the seventh embodiment of the present invention.

FIG. 13 is an operation explanatory diagram of the eighth embodiment of the present invention.

FIG. 14 is a configuration diagram of an eighth embodiment of the present invention.

FIG. 15 is a diagram showing a general control circuit of a voltage type self-exciting converter.

FIG. 16 is a configuration diagram of a ninth embodiment of the present invention.

FIG. 17 is a configuration diagram of a tenth embodiment of the present invention.

FIG. 18 is an operation explanatory diagram of the tenth embodiment of the present invention.

FIG. 19 is a configuration diagram of an eleventh embodiment of the present invention.

FIG. 20 is an explanatory diagram of a gain adjuster of the present invention.

FIG. 21 is an operation explanatory diagram of the eleventh embodiment of the present invention.

FIG. 22 is an operation explanatory diagram of the eleventh embodiment of the present invention.

FIG. 23 is an operation explanatory diagram of the eleventh embodiment of the present invention.

FIG. 24 is a configuration diagram of a twelfth embodiment of the present invention.

FIG. 25 is an explanatory diagram of a gain adjuster of the present invention.

FIG. 26 is a configuration diagram of a fourteenth embodiment of the present invention.

FIG. 27 is an operation explanatory diagram of the fourteenth embodiment of the present invention.

FIG. 28 is a configuration diagram of a fifteenth embodiment of the present invention.

FIG. 29 is a diagram showing another configuration of the fifteenth embodiment of the present invention.

FIG. 30 is a configuration diagram of a sixteenth embodiment of the present invention.

FIG. 31 is a diagram showing a configuration of a conventional rotary frequency converter.

FIG. 32 is a diagram showing a configuration of a frequency conversion device using a voltage type self-exciting converter.

FIG. 33 is a diagram showing the relationship between the load and the loss of the rotary frequency converter and the static frequency converter.

FIG. 34 is a diagram showing waveforms of various parts of the frequency conversion system when a train, which is a load, is input.

[Explanation of symbols]

1 ... AC system 2A-2H ... Transformer 3A, 3B ... Synchronous motor 4A, 4B ... AC generator 5 ... Transmission line 6 ... Scott transformer 7A-7D ... Voltage type self-exciting converters 8, 8A, 8B ... DC capacitors 9, 9A ... AC current detector 10 ... Three-phase full-wave rectifiers 11A-11D ... Level setters 12A-12C ... Level detectors 13A to 13C ... Effective value calculation circuits 14, 14A ... Maximum value selection circuit 15 ... OR circuit 16 ... Reversed phase detection circuits 17A-17D ... Time average calculation circuit 18 ... .... On-delay circuits 19A, 19B ... Level comparator with hysteresis characteristic 20 ... Circuit breaker 21 ... Initial charging circuit 22 ... AC voltage detector 23 ... Coordinate conversion circuit 24 ... High order Control circuit 25: Constant current control circuit 26 ... Coordinate reverse conversion circuit 27 ... Pulse width modulation circuit 28 ... Gain adjustment circuit 29 ... AND circuit 30 ... Reversed phase extraction circuit 31 ... Limiter circuit 101 ... Stationary Type frequency converter 102 ... Rotating type frequency converter

Continuation of the front page (56) Reference JP-A-10-225193 (JP, A) JP-A-8-214550 (JP, A) JP-A-62-201065 (JP, A) JP-B-49-46581 (JP , B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02M 7/48 H02M 7/64

Claims (6)

(57) [Claims] 1. A self-extinguishing element comprising alternating current to direct current
The first voltage type self-exciting converter that converts direct current to alternating current
Direct connection to the DC terminal of the first voltage type self-excited converter
Current capacitor and the DC capacitor are connected to the DC terminal.
Static frequency converter consisting of a second voltage type self-exciting converter
Rotation composed of a switching device, a synchronous motor and an AC generator
Frequency conversion system consisting of parallel connection with a frequency converter
System, measure the output current of the frequency conversion system.
Measuring means and detecting the anti-phase component from the output of the measuring means
The anti-phase detection means and the fact that the anti-phase component exceeds a certain value.
And a level detecting means for detecting the level.
The static frequency converter can be activated based on the output of the stage.
And a frequency conversion system characterized by. 2. A self-extinguishing element is used to convert alternating current to direct current.
The first voltage type self-exciting converter that converts direct current to alternating current
Direct connection to the DC terminal of the first voltage type self-excited converter
Current capacitor and the DC capacitor are connected to the DC terminal.
Static frequency converter consisting of a second voltage type self-exciting converter
Rotation composed of a switching device, a synchronous motor and an AC generator
Frequency conversion system consisting of parallel connection with a frequency converter
System, measure the output current of the frequency conversion system.
Measuring means and the effective value of each phase of the output of the measuring means.
Select the effective value detection means to be output and the maximum value of the effective value of each phase
Maximum value selection means and the maximum value of the effective value of each phase is a constant value
A first level detecting means for detecting that
Anti-phase detecting means for detecting anti-phase component from output of measuring means
And a second level that detects that the anti-phase component exceeds a certain value.
A bell detecting means, and a first level detecting means and a second level detecting means.
Based on the output of the level detection means of the
Frequency conversion system characterized by activating a device. 3. The detector for detecting the reverse phase is provided after the reverse phase detecting means.
Time average calculation to detect the average value of the output value in a fixed time
The frequency according to claim 1, further comprising means.
Number conversion system. 4. The level detecting means has a hysteresis characteristic.
The frequency variation according to claim 1, characterized in that
Exchange system. 5. The output after the static frequency converter is activated.
Frequency to the output current of the frequency conversion system
From the negative phase current contained in the output current of the conversion system Rotary type
Subtract the allowable reverse-phase current of the frequency converter and set the value to frequency.
The value obtained by dividing the value obtained by dividing by the negative phase current of the number conversion system
The frequency conversion system according to claim 1, wherein
Tem. 6. Included in the output current of the frequency conversion system.
The anti-phase current detection means for detecting the anti-phase component to be included,
The output current reference after starting the static frequency converter is
The output of the anti-phase current detection means is the anti-phase voltage of the frequency conversion system.
Subtract the rated negative phase current of the rotary frequency converter from the current,
The value obtained by dividing the value by the negative phase current of the frequency conversion system
The value according to claim 1, which is a multiplied value.
Wave number conversion system.