JPH10191697A - Control apparatus for wound-rotor induction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reset a frequency converter quickly and stably. SOLUTION: A frequency-converter control part 8A, to which a protective- device operating signal (a) expressing the short-circuit protective operation of an overvoltage protective device 5 is input, holds a stop signal (c) used to stop a frequency converter 4 so as to be output to the frequency converter 4. On the other hand, the frequency-converter control part, to which an operation permission signal (b) is input, releases the holding operation of the stop signal (c). A sequence control part 9A is provided with a timing judgment means by which a short-circuit release signal (d) used to release the short-circuit protective operation of the overvoltage protective device 5 and the operation permission signal (b) are output when a state which can stably control the frequency converter 4 is judged according to the magnitude of a short-circuit current signal as its correspondent signal flowing to the overvoltage protective device 5.

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 winding type induction machine for controlling overvoltage of a winding type induction machine for performing AC excitation control on a secondary winding side of the winding type induction machine.

[0002]

2. Description of the Related Art In a winding type induction machine, a primary winding side is connected to an electric power system, and a secondary winding side is excited at a slip frequency. When the primary winding becomes unbalanced, a negative-phase current flows, and a current of 2f1 ± sf1 (f1 is the frequency of the system and s is slip) flows through the secondary winding. When a DC component is applied to the primary winding, a current fr (rotation frequency of the rotor) flows to the secondary winding.

However, the frequency converter that excites the secondary winding side of the wound-type induction motor has elements (for example, thyristor, GTO, etc.) in the frequency converter so that current flows at a frequency of 2f1 ± sf1, or fr. ) Cannot be fired, the secondary winding side of the wound induction machine is released, and an abnormally high voltage is generated. Therefore, when a high voltage is generated on the secondary winding side of the wound-type induction machine, insulation breakdown occurs on the secondary winding side and the frequency converter, which may lead to a serious accident as a power plant.

Therefore, in order to solve such a problem, when an overvoltage occurs on the secondary winding side of the wound induction machine, the secondary winding side is directly short-circuited or short-circuited via a resistor. A method has been considered in which the voltage is reduced to almost zero to protect the secondary winding and the frequency converter from overvoltage.

FIG. 19 is a system diagram of a control device of a conventional wound induction machine.

In the figure, a primary winding 1 of a winding type induction machine 1 is shown.
a is connected to the system bus 3 via the transmission line 2. Further, a frequency converter 4 whose power supply side is connected to the power transmission line 2 is connected to the secondary winding 1b of the wound induction machine 1. Further, an overvoltage protection device 5 is connected to the secondary winding 1b of the wound induction machine 1, and the secondary winding 1b and the overvoltage protection device 5 are connected to the secondary winding 1b.
Is provided with a short-circuit current detector 7 for detecting a short-circuit current. Also, the primary winding 1a of the wound induction machine 1
Is provided with a primary voltage detector 6 for detecting a primary voltage which is a voltage of the primary winding 1a.

When an overvoltage is generated on the secondary winding 1b side of the wound induction machine 1, the overvoltage protection device 5 operates to activate the secondary winding 1b.
Short-circuit the b side to suppress overvoltage. At the same time, the overvoltage protection device 5 outputs a protection device operation signal a to the frequency converter control unit 8. When the protection device operation signal a is input as shown in FIG. 20, the frequency converter control unit 8 sets the flip-flop operation means 8b, outputs the frequency converter stop signal c to the frequency converter 4, and The converter 4 is stopped.

On the other hand, in the primary voltage monitoring means 8a, FIG.
As shown in (1), the primary voltage input from the primary voltage detector 6 is monitored, and when the primary voltage exceeds a specified value, the primary voltage return signal is turned on and the flip-flop operation means 8b is reset. As a result, the frequency converter stop signal c is released, and the frequency converter 4 is restarted. After the restart, the frequency converter control unit 8 controls the frequency converter 4 to take in the short-circuit current flowing in the overvoltage protection device 5 and return it to the system bus 3 side.

The sequence control section 9 inputs the short-circuit current from the short-circuit current detector 7, and determines whether or not the short-circuit current is equal to or less than a specified value by the timing determining means 9a.
If it is less than the specified value in this determination, the short-circuit release signal d
To output a short-circuit release signal d to the overvoltage protection device 5. The overvoltage protection device 5 receives the short-circuit release signal d,
When the short-circuit current becomes zero, the cancellation of the short-circuit is completed. FIG.
9 and FIG. 20, the control device (not shown) for controlling the cycloconverter is provided in the frequency converter 4 so that the secondary current becomes a higher-order current command.

FIG. 21 shows a system diagram of another conventional control device for a wound wire induction machine.

In FIG. 21, a primary winding 1a of the wound induction machine 1 is connected to a system bus 3 via a transmission line 2. A frequency converter 4, for example, a cycloconverter connected to the transmission line 2 is connected to the secondary winding 1 b of the wound induction machine 1. Further, the secondary winding 1 b of the wound induction machine 1 is connected to the overvoltage protection device 5 via the resistor 17. A secondary current detector 12 is provided in the output circuit of the frequency converter 4, and the detection signal is input to the frequency converter control unit 8. The frequency converter control unit 8 controls the frequency converter 4 by outputting a phase pulse signal p so as to make the deviation zero according to the deviation between the current command value and the detection signal from the secondary current detector 12. It is. Also, when the secondary winding side of the wound induction machine 1 is short-circuited by the overvoltage protection device 5, the output side of the frequency converter 4 is also short-circuited. When the capacity of the overvoltage protection device 5 is large, the resistor 17 may not be provided.

With such a configuration, if a failure occurs in the system bus 3 or the transmission line 2 and the primary winding side of the wound induction machine 1 becomes unbalanced, 2f1 ± sf
One alternating current occurs. In this case, the frequency converter 4 is 2f
Since it cannot follow the frequency of 1 ± sf1, the secondary winding 1b of the wound induction machine 1 is momentarily opened, and an overvoltage occurs. When an overvoltage occurs in the secondary winding 1b of the wound induction machine 1, the overvoltage protection device 5 is activated, and the secondary winding 1b of the wound induction machine 1 and the output side of the frequency converter 4 are connected to the resistor 17 in both three phases. Is short-circuited. Therefore, a short-circuit current flows through the overvoltage protection device 5 on the secondary winding side of the wound induction machine 1. The frequency converter control unit 8 controls the frequency converter 4 to take this short-circuit current. The frequency converter control unit 8 releases the short circuit when the current flowing through the overvoltage protection device 5 becomes almost zero, and shifts to normal control.

[0013]

In the case shown in FIGS. 19 and 20, when the overvoltage protection device 5 is short-circuited, the secondary current of the wound induction machine 1 flows because the current exceeds the rated current of the frequency converter 4. If the secondary current is controlled so as to be taken by the frequency converter 4, the frequency converter 4 flows a current higher than the rated current, so that commutation failure is likely to occur and the frequency converter 4 becomes unstable.

Further, since the short-circuit current is a difference (slip frequency) between the frequency of the primary current of the wound-type induction machine 1 and the rotation frequency of the winding-type induction machine 1, when the rotation speed is near the synchronous speed,
The slip frequency is close to zero and the frequency of the short-circuit current is small, almost like a DC current. Once the short-circuit current becomes larger than the current that can be taken by the frequency converter 4, it takes time to return. When the rotation speed is away from the synchronization speed, the short-circuit current increases instantaneously and decreases rapidly. The timing at which the short-circuit current increases as described above depends on the slip, and thus varies depending on operating conditions.

In such a case, in the conventional method, after the overvoltage protection device 5 is short-circuited, the condition for resetting the terminal voltage and the timing by the timer are uniformly determined. Therefore, the frequency converter 4 is restarted to convert the short-circuit current to the frequency. However, there is a problem that commutation fails because the short-circuit current exceeds the rated current of the frequency converter 4 and the operation must be stopped, and the operation return is delayed. .

In the case shown in FIG.
When an overvoltage is generated in the secondary winding 1b, the secondary winding of the wound induction machine 1 and the output side of the frequency converter 4 are short-circuited by the overvoltage protection device 5, and the secondary winding of the wound induction machine 1 is shorted. 1b
The normal operation is resumed by releasing the overvoltage protection device 5 and starting the frequency converter 4 in anticipation of the time when the current flowing between the overvoltage protection device 5 and the overvoltage protection device 5 becomes zero.

However, in such a conventional method, even if an attempt is made to control the current flowing through the overvoltage protection device 5 to zero, the current cannot be controlled to zero if there is a deviation in the zero point of the circuit for current detection or the like. The offset remains, and it takes a long time to erase the thyristor as a current equal to or less than the holding current. As a result, there is a problem in that the operation return is delayed.

This will be described with reference to FIG.
In the previous normal state, since the overvoltage protection device 5 is not operating, the current ig on the secondary winding side shown in the figure and the output current ic on the frequency converter side are the same, and the short-circuit current iovp changes to zero. Now, at time t1, when an overvoltage is generated on the secondary winding side of the wound induction machine 1, the overvoltage protection device 5 is short-circuited by overvoltage detection means (not shown) of the overvoltage protection device 5 and protected by the frequency converter control unit 8. The device operation signal a is output, and the frequency converter 4 is stopped by the phase pulse signal p.
As a result, a short-circuit current flows to the overvoltage protection device 5, and the output current ic on the frequency converter side becomes zero.

Thereafter, the overvoltage decreases, and at time t2, the frequency converter stop signal c from the frequency converter controller 8 is released by means (not shown), the frequency converter 4 returns, and the short circuit is released from the frequency converter controller 8. The signal d is output to the overvoltage protection device 5. As a result, the frequency converter 4 is controlled to take over the short-circuit current, and the short-circuit current decreases.
In this case, the frequency converter control unit 8 controls the frequency converter 4 so that the short-circuit current becomes a current command signal, but the zero point is shifted due to unbalance of the secondary current detector 12 and the like and the circuit. And the offset z remains, the thyristor cannot be erased, and the overvoltage protection device 5 cannot be released, so that it takes time to return to operation.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for a wound-type induction machine which enables a quick restart operation when the device is stopped after the operation of the overvoltage protection device.

[0021]

According to a first aspect of the present invention, a primary winding is connected to a system bus while a secondary winding is AC-excited, and a power supply is supplied from the system bus. Frequency converter that excites the secondary winding of a wound-type induction machine with AC power, and each of the three phases to prevent overvoltage generated in three phases between the wound-type induction machine and the frequency converter due to a system bus fault. An overvoltage protection device for short-circuiting and protecting the frequency converter and the overvoltage protection device.In the control device of the winding induction machine for controlling the overvoltage protection device, a protection device operation signal indicating a short circuit protection operation of the overvoltage protection device is input. A frequency converter control unit that holds a stop signal for stopping the frequency converter and outputs the signal to the frequency converter and inputs an operation permission signal to release the hold of the stop signal, and a short-circuit current flowing to the overvoltage protection device Signal or phase A sequence including timing determination means for outputting a short-circuit release signal for releasing the short-circuit protection operation of the overvoltage protection device and an operation permission signal when it is determined that the frequency converter can be stably controlled according to the magnitude of the signal. A control unit is provided. According to this means, it is determined by the timing determining means whether or not the frequency converter is in a state in which control can be started stably according to the magnitude of the short-circuit current or the equivalent current. At this time, a short-circuit release signal is output to the overvoltage protection device, and a release signal for releasing the stop signal based on the restart permission signal is output to the frequency converter. This allows the short-circuit current to be absorbed when the frequency converter is restarted,
The short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to a second aspect of the present invention, in the control device for a wound-type induction machine according to the first aspect, the timing determining means determines that the magnitude of the active power signal output from the wound-type induction machine is equal to or smaller than a predetermined value. According to this means, which outputs a short-circuit release signal and a re-operation permission signal, the timing judging means makes it possible to detect an overvoltage when the magnitude of the active power signal proportional to the short-circuit current signal falls below a predetermined value. A short-circuit release signal is output to the protection device, and a release signal for releasing the stop signal based on the restart signal is output to the frequency converter. Thereby, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to a third aspect of the present invention, in the control device for a wound-type induction machine according to the first aspect, the timing determining means cancels the short-circuit when the magnitude of the torque detection signal of the wound-type induction machine falls below a predetermined value. A signal and a re-operation permission signal are output. According to this means, when the magnitude of the torque detection signal proportional to the secondary current signal becomes equal to or smaller than a predetermined value, the timing determination means outputs a short-circuit release signal to the overvoltage protection device, and outputs a restart signal to the frequency converter. A release signal for releasing the stop signal based on the control signal is output. Thereby, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to a fourth aspect of the present invention, in the control apparatus for a wire-wound induction machine according to the first aspect, the timing judging means is provided when the q-axis component signal of the secondary current of the wire-wound induction machine becomes a predetermined value or less. A short-circuit release signal and a re-operation permission signal are output. According to this means, when the magnitude of the secondary current q-axis component proportional to the short-circuit current signal becomes equal to or smaller than the predetermined value, the timing judgment means outputs a short-circuit release signal to the overvoltage protection device and re-transmits the signal to the frequency converter. A release signal for releasing the stop signal based on the operation signal is output. Thereby, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to a fifth aspect of the present invention, in the control device for a wound-type induction machine according to the first aspect, the timing determining means short-circuits when a q-axis component signal of the primary current of the wound-type induction machine becomes a predetermined value or less. A release signal and a re-operation permission signal are output. According to this means, when the magnitude of the primary current q-axis component proportional to the short-circuit current signal becomes equal to or less than the predetermined value, the timing determination means outputs a short-circuit release signal to the overvoltage protection device, and restarts the frequency converter. A release signal for releasing the stop signal based on the signal is output. Thereby, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to a sixth aspect of the present invention, in the control apparatus for a wound-type induction machine according to the first aspect, the timing determining means determines a frequency of the short-circuit current obtained from slip of the wound-type induction machine and an active power of the wound-type induction machine. The time at which the short-circuit current becomes equal to or less than the rated power of the frequency converter is calculated from the magnitude of the short-circuit current amplitude obtained from the signal, and when the calculated time comes, a short-circuit release signal and a restart permission signal are output. Things.
According to this means, the timing determining means calculates the time at which the short-circuit current becomes equal to or less than the predetermined value based on the frequency of the short-circuit current calculated from the slip and the amplitude of the short-circuit current calculated from the active power. Then, a short-circuit release signal is output to the overvoltage protection device, and a release signal for releasing the stop signal based on the restart signal is output to the frequency converter. Thereby, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly and without commutation failure,
Stable control can be continued after restart.

According to a seventh aspect of the present invention, there is provided a wound-type induction machine in which the primary winding is connected to the system bus while the secondary winding is AC-excited, and a power is supplied from the system bus to the winding-type induction machine. A frequency converter that excites the secondary winding of AC and a three-phase short-circuit to protect the three-phase overvoltage between the wound induction machine and the frequency converter due to an accident in the system bus. An overvoltage protection device, comprising: a control device for a winding type induction machine for controlling the frequency converter and the overvoltage protection device, wherein when the short-circuit current approaches zero after a short-circuit operation of the overvoltage protection device, the short-circuit current of the thyristor is quickly increased. A frequency converter control unit having a return means for zero-crossing so as to have a holding current or less is provided. According to this means, when the short-circuit current approaches zero, the short-circuit current crosses zero by the return means. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

According to an eighth aspect of the present invention, in the control device for a wound-type induction machine according to the seventh aspect, the frequency converter control section controls the AC excitation current signal output from the frequency converter at normal times to be a current command signal. Computing means for switching after the short-circuit operation and outputting the short-circuit current near zero,
A gain variable means for increasing or decreasing the calculation gain of the calculation means is provided, and when the short-circuit current approaches zero, the calculation gain of the gain variable means is increased to cause the short-circuit current to cross zero. According to this means, when the short-circuit current signal approaches zero, the gain of the control means for inputting the short-circuit current signal is increased, and the short-circuit current is increased or decreased at a predetermined amplitude centering on zero, thereby causing a zero cross. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

According to a ninth aspect of the present invention, in the control device of the wire-wound induction machine according to the seventh aspect, the frequency converter control section controls the AC excitation current signal output from the frequency converter at normal time to be a current command signal. Computing means for switching after the short-circuit operation and outputting the short-circuit current near zero,
Amplitude signal generating means for generating an amplitude signal having a predetermined width centered on zero, and when the short-circuit current signal becomes close to zero, an amplitude signal is added to the signal from the amplitude signal generating means to cross the short-circuit current to zero. It is intended to be. According to this means, when the short-circuit current signal approaches zero, an amplitude signal centered on a predetermined zero of the short-circuit current signal is added, and a zero cross is made. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

According to a tenth aspect of the present invention, in the control device for a wire-wound induction machine according to the seventh aspect, the frequency converter control section comprises:
A control means for controlling the AC excitation current signal output from the frequency converter during normal operation to be a current command signal, and switching after the short-circuit operation to output the short-circuit current near zero; Amplitude signal generating means for generating an amplitude signal having a width, wherein when the short-circuit current signal becomes close to zero, the amplitude signal is added to the output signal from the arithmetic means from the amplitude signal generating means so that the short-circuit current crosses zero. It was made. According to this means, when the short-circuit current signal approaches zero, an amplitude signal centered at a predetermined zero is added to the output signal of the arithmetic means for inputting the short-circuit current signal, and zero crossing is performed. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are block diagrams of a control device for a wound-type induction machine according to a first embodiment of the present invention. The same reference numerals as those in FIGS. 1 and 2 show a corresponding part.
0A, a sequence control unit 9A and a frequency converter control unit 8
A, the frequency converter 4 is stopped after the operation of the overvoltage protection device 5, and the frequency converter 4 is restarted with the short-circuit current smaller than the rated current of the frequency converter 4. 4 is characterized in that the short-circuit current is promptly taken to release the short-circuit of the overvoltage protection device 5, so that the frequency converter 4 does not fail in commutation and can continue stable control even after restarting.

In the first to sixth embodiments of the present invention, the frequency converter 4 is provided with control means (not shown) for controlling the cycloconverter so that the secondary current becomes a higher-order current command. I have.

Here, the frequency converter control unit 8A operates as shown in FIG.
Has flip-flop operation means 8b,
The sequence control unit 9A has a timing determination unit 9a.

First, when the protection device operation signal a is input, the frequency converter control section 8A sets the flip-flop operation means 8b, outputs the frequency converter stop signal c to the frequency converter 4, and outputs the signal to the frequency converter 4. And the frequency converter 4 is stopped.

The sequence control section 9A receives the short-circuit current from the short-circuit current detector 7 and inputs the short-circuit current to the timing determination section 9a.
Then, if the short-circuit current is smaller than the rated current of the frequency converter 4, the re-operation permit signal b is output to the frequency converter control unit 8A, and the short-circuit release signal d is output to the overvoltage protection device 5. Output.

The frequency converter control section 8A resets the flip-flop operation means 8b by the restart permission signal b. As a result, the frequency converter control unit 8A releases the frequency converter stop signal c, returns control means (not shown), restarts the frequency converter 4, and takes over the short-circuit current flowing through the overvoltage protection device 5. To control. The overvoltage protection device 5 receives the short-circuit release signal d, sets the short-circuit current to zero, and completes the short-circuit release.

As described above, according to the first embodiment, the overvoltage protection device 5 suppresses the overvoltage of the secondary winding 1b of the wound-type induction machine 1, while preventing the frequency converter 4 from short-circuiting the secondary winding. By appropriately taking the restart timing, the short-circuit current is immediately taken after the re-operation of the frequency converter 4 to release the short-circuit, and stable control can be performed without the frequency converter 4 failing to commutate. Operation can be resumed.

FIGS. 3 and 4 are block diagrams of a control device for a wire wound induction machine according to a second embodiment of the present invention. The same reference numerals as those in FIGS. FIG. 3 and FIG.
0B, the sequence controller 9B and the frequency converter controller 8
B, the active power is the secondary current of the wound induction machine 1 (same as the short-circuit current when the overvoltage protection device 5 is short-circuited).
Focusing on the fact that the short-circuit current becomes equal to or less than the specified value and the short-circuit current becomes equal to or less than the rated current of the frequency converter 4,
It is characterized in that the frequency converter 4 is operated again to control the commutation without failure, while the short-circuit current can be quickly taken out and the short-circuit can be released.

Here, the frequency converter control unit 8B operates as shown in FIG.
As shown in (1), the flip-flop operation means 8b is provided, and the sequence control section 9B is provided with a timing determination means 9a and an active power monitoring means 9b.

First, when the protection device operation signal a is input, the frequency converter control unit 8B sets the flip-flop operation means 8b, outputs the frequency converter stop signal c to the frequency converter 4, and outputs the signal to the frequency converter 4. And the frequency converter 4 is stopped.

Next, the sequence control unit 9B takes in the active power detected by the active power detector 10, and turns on the active power small signal e if the active power is below the specified level by the active power monitoring means 9b. And the timing determining means 9
“a” outputs the restart permission signal “b” to the frequency converter control unit 8B based on the small active power signal “e”, and outputs the short-circuit release signal “d” to the overvoltage protection device 5.

The frequency converter control section 8B resets the flip-flop operation means 8b with the restart operation permission signal b. As a result, the frequency converter stop signal c is released, the built-in control means (not shown) is returned, the frequency converter 4 is restarted, and the short-circuit current flowing to the overvoltage protection device 5 is controlled to be taken. The frequency converter 4 quickly receives the short-circuit current, and the overvoltage protection device 5 inputs the short-circuit release signal d and sets the short-circuit current to zero to complete the short-circuit release.

As described above, according to the second embodiment, while the overvoltage of the secondary winding 1b of the wound induction machine 1 is suppressed by the overvoltage protection device 5, the overvoltage protection device 5 is short-circuited due to the magnitude of the active power. By appropriately setting the restart timing of the frequency converter 4 during the operation, the short-circuit current is quickly taken after the frequency converter 4 is restarted, the short circuit is released, and the frequency converter 4 is stabilized without commutation failure. And the operation can be returned quickly.

FIGS. 5 and 6 are block diagrams of a control device for a wire wound induction machine according to a third embodiment of the present invention. The same reference numerals as those in FIGS. FIG. 5 and FIG.
0C, the sequence control unit 9C and the frequency converter control unit 8
C, and paying attention to the fact that the torque of the wound wire induction machine 1 is proportional to the secondary current, when the torque of the wound wire induction machine 1 becomes equal to or less than a specified value, the frequency converter 4 is restarted, It is characterized in that the short circuit current of the overvoltage protection device 5 is quickly taken by the frequency converter 4 to release the short circuit.

Here, the frequency converter control section 8C has flip-flop operation means 8b, and the sequence control section 9C
Has a timing determining means 9a and a torque monitoring means 9c.

First, when the protection device operation signal a is input, the frequency converter control section 8C sets the flip-flop operation means 8b, outputs the frequency converter stop signal c to the frequency converter 4, and outputs the signal to the frequency converter 4. And the frequency converter 4 is stopped.

Next, the sequence control unit 9C takes in the torque of the wound induction machine 1 detected by the torque detector 11, and turns on the small torque signal f if the torque is below the specified value by the torque monitoring means 9c. And the timing determining means 9
a turns on the restart permission signal b and the short-circuit release signal d by the small torque signal f, outputs the restart permission signal b to the frequency converter control unit 8C, and outputs the short-circuit release signal d to the overvoltage protection device 5.

The frequency converter control section 8C resets the flip-flop operation means 8b by the restart permission signal b. As a result, the frequency converter stop signal c is released, the built-in control means (not shown) is restored, and the frequency converter 4
Is restarted and the short-circuit current flowing in the overvoltage protection device 5 is controlled to be taken. The frequency converter 4 quickly receives the short-circuit current, and the overvoltage protection device 5 outputs the short-circuit release signal d.
And the short-circuit current is set to zero to complete the short-circuit release.

As described above, according to the third embodiment, the overvoltage protection device 5 suppresses the overvoltage of the secondary winding 1b of the wound induction machine 1 while the overvoltage protection device 5 is short-circuited due to the magnitude of the torque. By appropriately setting the restart timing of the frequency converter 4, the short-circuit current is quickly taken after the frequency converter 4 is restarted, the short circuit is released, and stable control is performed without causing the commutation failure of the frequency converter 4. And the operation can be returned quickly.

FIGS. 7 and 8 are block diagrams of a control device for a wire wound induction machine according to a fourth embodiment of the present invention. The same reference numerals as those in FIGS. FIG. 7 and FIG.
The sequence control unit 9D and the frequency converter control unit 8
D, the short-circuit current is q of the secondary current of the winding type induction machine 1.
Paying attention to the point proportional to the axis component, when the q-axis component of the secondary current becomes equal to or less than the specified value, the short-circuit current of the overvoltage protection device 5 is reduced without restarting the frequency converter 4 without commutation failure. It is characterized in that it is quickly taken out and the short circuit is released.

First, when the protection device operation signal a is input, the frequency converter control section 8D sets the flip-flop operation means 8b, outputs a frequency converter stop signal c to the frequency converter 4, and outputs a frequency converter stop signal c to the frequency converter 4. And the frequency converter 4 is stopped.

First, the sequence control section 9D takes in the secondary current detected by the secondary current detector 12, and detects the secondary current q-axis component signal g by the secondary current q-axis component detection means 9d. The secondary current q-axis component monitoring means 9e turns on the restart enable signal b and the short-circuit release signal d by the secondary current q-axis component small signal h when the secondary current q-axis component signal g is equal to or less than the specified value. Then, the re-operation permission signal b is output to the frequency converter control unit 8D, and the short-circuit release signal d is output to the overvoltage protection device 5.

The frequency converter control section 8D resets the flip-flop operation means 8b by the restart permission signal b. As a result, the frequency converter stop signal c is released, the built-in control means (not shown) is returned, the frequency converter 4 is restarted, and the short-circuit current flowing to the overvoltage protection device 5 is controlled to be taken. The frequency converter 4 quickly receives the short-circuit current, and the overvoltage protection device 5 receives the short-circuit release signal d and sets the short-circuit current to zero to complete the short-circuit release.

As described above, according to the fourth embodiment, the overvoltage protection device 5 suppresses the overvoltage of the secondary winding 1b of the wound induction machine 1, and reduces the magnitude of the secondary current q-axis component signal g. The overvoltage protection device 5 appropriately sets the restart timing of the frequency converter 4 during the short-circuit, so that the frequency converter 4
Immediately after restarting, the short-circuit current is taken and the short-circuit is released,
Stable control can be performed without causing the frequency converter 4 to fail in commutation.

FIGS. 9 and 10 are block diagrams of a control device for a wire-wound induction machine according to a fifth embodiment of the present invention.
The same reference numerals as those in FIGS. 19 and 20 denote the same or corresponding parts, and FIGS. 9 and 10 show a sequence control unit 9E and a frequency converter control unit 8E provided in a control device 100E to provide a short-circuit current. Paying attention to the fact that is proportional to the q-axis component of the primary current of the wound induction machine 1, when the q-axis component of the primary current becomes equal to or less than a specified value, the frequency converter 4 is restarted and commutation fails. Instead, it is characterized in that the short-circuit current of the overvoltage protection device 5 is quickly taken out and the short-circuit is released.

First, when the protection device operation signal a is input, the frequency converter control unit 8E sets the flip-flop operation means 8b, outputs a frequency converter stop signal c to the frequency converter 4, and outputs a frequency converter stop signal c to the frequency converter 4. And the frequency converter 4 is stopped.

First, the sequence control section 9E takes in the primary current detected by the primary current detector 13, and detects the primary current q-axis component signal g by the primary current q-axis component detection means 9f. The primary current q-axis component monitoring means 9g turns on the primary current q-axis component small signal j when the primary current q-axis component signal i is equal to or less than a specified value. Timing judgment means 9
a is a restart operation permission signal b based on the primary current q-axis component small signal j.
Then, the short-circuit release signal d is turned on, the restart operation permission signal b is output to the frequency converter control unit 8E, and the short-circuit release signal d is output to the overvoltage protection device 5.

The frequency converter control unit 8E resets the flip-flop operation means 8b with the restart operation permission signal b. As a result, the frequency converter stop signal c is released, the built-in control means (not shown) is returned, the frequency converter 4 is restarted, and the short-circuit current flowing to the overvoltage protection device 5 is controlled to be taken. The frequency converter 4 quickly receives the short-circuit current, and the overvoltage protection device 5 receives the short-circuit release signal d and sets the short-circuit current to zero to complete the short-circuit release.

As described above, according to the fifth embodiment, while the overvoltage protection device 5 suppresses the overvoltage of the secondary winding 1b of the wound induction machine 1, the overvoltage protection device is determined based on the magnitude of the primary current q-axis component. By appropriately setting the restart timing of the frequency converter 4 during the short circuit, the short circuit current is quickly taken after the frequency converter 4 is restarted, the short circuit is released, and the commutation of the frequency converter 4 does not fail. Can be controlled stably.

FIGS. 11 and 12 are block diagrams of a control device for a wound-type induction machine showing a sixth embodiment of the present invention. The same reference numerals as those in FIGS. 11 and 12 show a sequence control unit 9F and a frequency converter control unit 8F provided in the control device 100F, and determine the frequency of the short-circuit current from the slip and the magnitude of the short-circuit current from the active power, respectively. By calculating, the timing at which the short-circuit current becomes equal to or less than the rated current of the frequency converter 4 is estimated. At this timing, the frequency converter 4 is restarted, and the frequency converter 4 promptly takes the short-circuit current and activates the overvoltage protection device 5. The short circuit is released, and the frequency converter 4 is characterized in that stable control is continued even after restarting without commutation failure.

First, when the protection device operation signal a is input, the frequency converter control section 8F sets the flip-flop operation means 8b, outputs the frequency converter stop signal c to the frequency converter 4, and outputs the signal to the frequency converter 4. And the frequency converter 4 is stopped.

Next, the sequence control section 9 F inputs the active power detected by the active power detector 10 and the slip frequency of the wound induction machine 1 detected by the slip frequency detector 14. The amplitude calculator 9h estimates the short-circuit current amplitude signal k from the active power, and the frequency calculator 9i estimates the short-circuit current frequency signal m from the slip frequency. The short-circuit current predicting means 9j predicts the timing at which the short-circuit current becomes zero from the short-circuit current amplitude signal k and the short-circuit current frequency signal m, and outputs a short-circuit release permission signal n to the timing determining means 9a at this timing. Timing judgment means 9
a turns on the re-operation permission signal b and the short-circuit release signal d by the short-circuit release permission signal n, outputs the re-operation permission signal b to the frequency converter control unit 8F, and outputs the short-circuit release signal d to the overvoltage protection device 5. .

The frequency converter control section 8F resets the flip-flop operation means 8b with the restart operation permission signal b. As a result, the frequency converter stop signal c is released, the built-in control means (not shown) is returned, the frequency converter 4 is restarted, and the short-circuit current flowing to the overvoltage protection device 5 is controlled to be taken. The frequency converter 4 quickly receives the short-circuit current, and the overvoltage protection device 5 inputs the short-circuit release signal d. When the short-circuit current becomes zero, the short-circuit release is completed.

As described above, according to the sixth embodiment, while the overvoltage protection device 5 suppresses the overvoltage of the secondary winding 1b of the wound induction machine 1, the overvoltage protection device is determined based on the magnitude of the active power and the slip frequency. 5 predicts an appropriate restart timing of the frequency converter 4 during the short circuit, thereby immediately taking out the short-circuit current after the restart of the frequency converter 4, releasing the short circuit, and causing the frequency converter 4 to fail in commutation. And stable control can be performed.

FIG. 13 is a block diagram of a control device for a wire-wound induction machine according to a seventh embodiment of the present invention. In FIG. 13, the same reference numerals as those in FIG.
FIG. 13 shows that the frequency converter control unit 8 is provided in the control device 101G.
When the overvoltage protection device 5 is reset by providing G, the short-circuit current is controlled so as to become zero, and when it becomes almost zero, the gain of the calculating means is increased and the current is oscillated to reduce the short-circuit current to zero. It is characterized in that it is crossed and the overvoltage protection device 5 is reset.

Here, the frequency converter control unit 8G operates as shown in FIG.
As shown in FIG. 4, a control means 8G1 is built in. The control means 8G1 includes a phase pulse output means (PHC) 8i for controlling the frequency converter 4, a PI calculation means 8c whose gain can be arbitrarily changed, and an overvoltage protection device. 5, the switching contacts 8e1 and 8e2 that are switched when the protection device operation signal a is input.
And a PI calculating means for determining a deviation between a current command signal input from a higher order through the switching contact 8e1 and a detection signal of the secondary current detector 12 when the overvoltage protection device 5 is inactive. When the overvoltage protection device 5 operates, the detection signal of the short-circuit current detector 7 and the detection signal of the secondary current detector 12 are added, and the added value is subtracted through the switching contact 8e2. It comprises an adding means 8g for giving a current command signal to 8f and a gain changing means 8c1 in addition to this.

Now, when an accident occurs in the system bus 3 or the transmission line 2 and an unbalanced voltage is generated in the winding of the primary winding of the wound induction machine 1, 2f1 due to the reverse phase component is generated in the secondary winding. ± s
An AC voltage of f1 is generated. Therefore, the frequency converter 4
Cannot follow the control according to the voltage at that time, the secondary winding of the wound induction machine 1 is momentarily opened, and an overvoltage occurs. At this time, the overvoltage protection device 5 operates by detecting this overvoltage, short-circuits the secondary winding 1b of the wound-type induction machine 1 and the output side of the frequency converter 4 in three phases, and also controls the frequency converter control unit 8G. The protection device operation signal a is input.

Here, the frequency converter control unit 8G operates as shown in FIG.
As shown in FIG. 5, the following relationship exists between the actual currents and the corresponding signals shown in FIG.
Means 8 immediately before the protection device operation signal a is input from the
The output signal ig of g is as shown in the following equations (1) and (2).

Ig = ic + iovp (1) iovp = 0 (2)

However, when the protection device operation signal a from the overvoltage protection device 5 is input, the switching contact 8e1 opens and the switching contact 8e2 closes, and the current command signal icI input to the subtraction means 8f is expressed by the following equation (3). Become like

IcI = ig = ic + iovp (3)

Here, the current command signal icI and the current signal i
Assuming that the deviation from c is Δic, the following equation (4) is obtained.

Δic = icI-ic (4)

From the above equations (2) and (3), the following equation (5) is obtained.
To (7).

IcI = ic + iovp (5) icI-ic = iovp (6) Therefore, Δic = icI-ic = iovp (7)

From the result, each signal shown in FIG.
There is a corresponding relationship with each current shown in FIG. Therefore, PI
Assuming that Δic, which is the input of the calculating means 8c, is 0, the short-circuit current iovp also becomes 0.

For example, as shown in FIG. 16 corresponding to FIG. 22, in a normal state before time t1, the protection device operation signal a from the overvoltage protection device 5 is off, and the control means 8G1 controls the higher-level current command signal icI. Is input through the contact 8e1, and the current signal ic of the frequency converter 4 is the current command signal ic.
I is controlled. Thus, the short-circuit current iovp is zero as shown in FIG. Thereafter, at time t1, when the overvoltage protection device 5 detects an overvoltage and short-circuits, a short-circuit current iovp flows, the contact 8e1 of the control means 8G1 shown in FIG. 14 opens, the contact 8e2 closes, and the phase The operation stop signal c1 is input to the pulse output means 8i, and the pulse output is stopped.

As a result, the current ic on the secondary winding side shown in FIG. 16 becomes zero. Eventually, when the overvoltage to the overvoltage protection device 5 decreases, the operation stop signal c1 to the phase pulse output means 8i is turned off, and the phase pulse signal p is output from the phase pulse output means 8i to the frequency converter 4. As a result, the current ic flows, but as shown in FIG.
In some cases, the offset z may remain in the short-circuit current iovp. In such a case, the offset z is detected,
The gain of the gain changing means 8c1 of the control means 8G1 shown in FIG. 14 is increased, and the output signal of the PI calculating means 8c hunts and vibrates, crosses zero at time t3, and the thyristor is erased.

As described above, according to the seventh embodiment, when the short-circuit current signal approaches zero, the gain of the arithmetic means for inputting the short-circuit current signal is increased, and the short-circuit current has a predetermined amplitude centered on zero. It is increased or decreased to make a zero cross. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

FIG. 17 is a block diagram of a control device for a wound wire induction machine showing an eighth embodiment of the present invention. The same reference numerals as in FIG. 14 showing the seventh embodiment denote the same or corresponding parts. FIG. 17 shows that the frequency converter control unit 8H has a control unit 8H1 built therein, and the control unit 8H1 additionally includes an amplitude signal generation unit 8h and an addition unit 8i1, and the overvoltage protection device 5
Is reset by the frequency converter control unit 8H so that the short-circuit current becomes zero. When the short-circuit current becomes almost zero, the vibration signal element is added to the current command signal to make the current zero-cross, thereby resetting early. It is characterized in that it is made as described above.

Now, when an accident occurs in the system bus 3 or the transmission line 2 and an unbalanced voltage is generated in the primary winding of the wound induction machine 1, 2f1 due to the negative phase component is generated in the secondary winding. ± s
An AC voltage of f1 is generated. Therefore, the frequency converter 4
Cannot follow the control according to the voltage at that time, the secondary winding of the wound induction machine 1 is momentarily opened, and an overvoltage occurs. Then, the overvoltage protection device 5 operates by detecting this overvoltage, short-circuits the secondary winding of the wound-type induction machine 1 and the output side of the frequency converter 4 in three phases, and provides the protection device to the frequency converter control unit 8H. An operation signal a is input.

Here, the frequency converter control unit 8H operates as shown in FIG.
As shown in FIG. 5, the following relationship exists between each current and each signal corresponding to FIG. 17, and the output signal ig of the adding means 8g immediately before the protection device operation signal a is input from the overvoltage protection device 5.
Is as shown in the following equations (8) and (9).

Ig = ic + iovp (8) iovp = 0 (9)

When the protection device operation signal a from the overvoltage protection device 5 is input, the switching contact 8e1 opens and the switching contact 8e2 closes, and the current command value i input to the subtraction means 8f
cI is as shown in the following equation (10).

IcI = ig = ic + iovp (10)

Here, assuming that the difference between the current command value icI and the actual current is Δic, the following equation (11) is obtained.

Δic = icI-ic (11)

Further, the following expressions (12) to (14) are obtained from the expressions (10) and (11).

IcI = ic + iovp (12) icI-ic = iovp (13) Therefore, Δic = icI-ic = iovp (14)

From the above, it can be seen that if Δic, which is the control deviation, is set to 0, the short-circuit current is set to 0.

For example, as shown in FIG. 16 corresponding to FIG. 22, in a normal state before time t1, the protection device operation signal a from the overvoltage protection device 5 is off, and the higher-level current command signal icI is controlled by the control means 8H1. The current signal ic input through the contact 8e1 and output from the frequency converter 4 is a current command signal icI.
It is controlled so that Thus, the short-circuit current iovp is zero as shown in FIG. Thereafter, at time t1, when the overvoltage protection device 5 detects an overvoltage and short-circuits, a short-circuit current iovp flows, and the protection device operation signal a
The contact 8e1 of the control means 8H1 is opened by the
2 is closed and the operation stop signal c1 is sent to the phase pulse output means 8i.
Is input and the pulse output is stopped.

As a result, the current ic on the secondary winding side shown in FIG. 16 becomes zero. Eventually, when the overvoltage to the overvoltage protection device 5 decreases, the operation stop signal c1 to the phase pulse output means 8i is turned off, and the phase pulse signal p is output from the phase pulse output means 8i to the frequency converter 4. This allows
Although the current ic flows, the offset z may remain in the short-circuit current iovp at time t2 as shown in FIG. In such a case, the offset z is detected, and FIG.
The amplitude signal is output from the amplitude / amplitude signal generating means 8h of the control means 8H1 shown in FIG.
cI vibrates and crosses zero, and the thyristor is erased.

As described above, according to the eighth embodiment, when the short-circuit current signal approaches zero, an amplitude signal centered on a predetermined zero is added to the short-circuit current signal, and zero crossing is performed.
Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

FIG. 18 is a block diagram of a control device for a wire wound induction machine showing a ninth embodiment of the present invention. The same reference numerals as those in FIG. 14 showing the seventh embodiment denote the same or corresponding parts. FIG. 18 shows that the frequency converter control unit 8I has a control unit 8I1 built therein. This control unit 8I1 additionally includes an amplitude signal generation unit 8h and an addition unit 8i1, and the overvoltage protection unit 5I
When resetting, control so that the short-circuit current becomes zero,
It is characterized in that the vibration signal element is added to the voltage command signal output from the PI calculation means 8c for the current at the time when the current becomes substantially zero, thereby causing the current to cross zero and reset.

Now, when an accident occurs in the system bus 3 or the transmission line 2 and an unbalanced voltage is generated in the primary winding of the wound induction machine 1, a 2f1 due to a negative phase component is generated in the secondary winding. ± s
An AC voltage of f1 is generated. Therefore, the frequency converter 4
Cannot follow the control according to the voltage at that time, the secondary winding of the wound induction machine 1 is momentarily opened, and an overvoltage occurs. Then, the overvoltage protection device 5 operates by detecting this overvoltage, short-circuits the secondary winding of the wound-type induction machine 1 and the output side of the frequency converter 4 for three phases, and also provides the protection device to the frequency converter control unit 8I. An operation signal a is input.

Here, the frequency converter control section 8I operates as shown in FIG.
As shown in FIG. 5, the following relationship exists between the currents and the corresponding signals shown in FIG. 18, and the output signal ig of the adding means 8g immediately before the protection device operation signal a is input from the overvoltage protection device 5 is And the following equations (15) and (16).

Ig = ic + iovp (15) iovp = 0 (16)

When the protection device operation signal a from the overvoltage protection device 5 is input, the switching contact 8e1 opens and the switching contact 8e2 closes, and the current command value i input to the subtraction means 8f
cI is as shown in the following equation (17).

IcI = ig = ic + iovp (17)

Here, assuming that a deviation between the current command value icI and the actual current is Δic, the following equation (18) is obtained.

Δic = icI-ic (18)

According to equations (17) and (18), the following equation (1)
9) to (21).

IcI = ic + iovp (19) icI-ic = iovp (20) Therefore, Δic = icI-ic = iovp (21)

As a result, if Δic, which is the control deviation, is set to 0, the short-circuit current iovp is set to 0.

For example, as shown in FIG. 16 corresponding to FIG. 22, in a normal state before time t1, the protection device operation signal a from the overvoltage protection device 5 is off, and the higher-level current command signal icI is controlled by the control means 8I1. The current signal ic input through the contact 8e1 and output from the frequency converter 4 is a current command signal icI.
It is controlled so that Thus, the short-circuit current iovp is zero as shown in FIG. Thereafter, at time t1, when the overvoltage protection device 5 detects an overvoltage and short-circuits, a short-circuit current iovp flows, and the protection device operation signal a
The contact 8e1 of the control means 8I1 is opened by the
2 is closed and the operation stop signal c1 is sent to the phase pulse output means 8i.
Is input and the pulse output is stopped.

As a result, the current ic on the secondary winding side shown in FIG. 16 becomes zero. Eventually, when the overvoltage to the overvoltage protection device 5 decreases, the operation stop signal c1 to the phase pulse output means 8i is turned off, and the phase pulse signal p is output from the phase pulse output means 8i to the frequency converter 4. As a result, the current ic flows, but as shown in FIG.
In some cases, the offset z may remain in the short-circuit current iovp. In such a case, the offset z is detected,
The amplitude signal is input from the amplitude signal generating means 8h of the control means 8I1 shown in FIG. 18 to the adding means 8i1. As a result, the output of the PI calculation means 8c vibrates and crosses zero, and the thyristor is erased.

As described above, according to the ninth embodiment, when the short-circuit current signal approaches zero, an amplitude signal centered on a predetermined zero is added to the output signal of the arithmetic means for inputting the short-circuit current signal, and the zero signal is added. Cross is done. Thus, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

[0109]

As described above, according to the first aspect of the present invention, the timing judging means judges whether or not the frequency converter can start the control stably according to the magnitude of the short-circuit current or the equivalent current. When the frequency converter is stably controllable, a short-circuit release signal is output to the overvoltage protection device, and a release signal for releasing the stop signal based on the restart permission signal is output to the frequency converter. The short circuit current is absorbed when the unit is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to the second aspect of the present invention, when the magnitude of the active power signal proportional to the short-circuit current signal becomes equal to or smaller than the predetermined value, the timing judging means outputs a short-circuit release signal to the overvoltage protection device. Since the release signal for releasing the stop signal based on the restart signal is output, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to the third aspect of the present invention, when the magnitude of the torque detection signal proportional to the secondary current signal falls below a predetermined value by the timing determination means, a short-circuit release signal is output to the overvoltage protection device, and the frequency conversion is performed. Since the release signal for releasing the stop signal based on the restart signal is output to the converter, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to the invention of claim 4, when the magnitude of the secondary current q-axis component proportional to the short-circuit current signal becomes smaller than a predetermined value, the timing judgment means outputs a short-circuit release signal to the overvoltage protection device, Since the release signal for releasing the stop signal based on the restart signal is output to the frequency converter, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to the fifth aspect of the present invention, when the magnitude of the primary current q-axis component proportional to the short-circuit current signal becomes equal to or smaller than the predetermined value, the timing judgment means outputs the short-circuit release signal to the overvoltage protection device, Since the release signal for releasing the stop signal based on the restart signal is output to the converter, the short circuit current is absorbed when the frequency converter is restarted, and the short circuit of the overvoltage protection device is released. Therefore, the frequency converter can be restarted quickly, and commutation does not fail, and stable control can be continued after the restart.

According to the present invention, the time at which the short-circuit current becomes equal to or less than the predetermined value is calculated based on the frequency of the short-circuit current calculated from the slip and the amplitude of the short-circuit current calculated from the active power by the timing determining means. At that time, a short-circuit release signal is output to the overvoltage protection device, and a release signal for releasing the stop signal based on the restart signal is output to the frequency converter, so that the short-circuit current is absorbed when the frequency converter is restarted. And the short circuit of the overvoltage protection device is released. Therefore,
The frequency converter can be restarted quickly, and without commutation failure, stable control can be continued after the restart.

According to the seventh aspect of the present invention, when the short-circuit current approaches zero, the short-circuit current crosses the zero-cross by the return means. The short circuit can be reliably released,
In addition, the frequency converter can be quickly restarted.

According to the invention of claim 8, when the short-circuit current signal approaches zero, the gain of the arithmetic means for inputting the short-circuit current signal is increased to increase or decrease the short-circuit current at a predetermined amplitude around zero. Therefore, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

According to the ninth aspect of the present invention, when the short-circuit current signal approaches zero, the short-circuit current signal is added with an amplitude signal centered at a predetermined zero to cause a zero cross, so that the short-circuit current remains as an offset. Even if it does not become zero, the short circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

According to the tenth aspect of the present invention, when the short-circuit current signal approaches zero, an amplitude signal centered at a predetermined zero is added to the control signal of the arithmetic means for inputting the short-circuit current signal to cause a zero cross. Therefore, even when the short-circuit current remains as an offset and does not become zero, the short-circuit of the overvoltage protection device can be reliably released, and the frequency converter can be quickly restarted.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a control device of a wire-wound induction machine according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a control device of the wound induction machine of FIG. 1;

FIG. 3 is a configuration diagram of a control device of a wire-wound induction machine showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a control device of the wound induction machine of FIG. 3;

FIG. 5 is a configuration diagram of a control device of a wire-wound induction machine showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a control device of the wirewound induction machine of FIG. 5;

FIG. 7 is a configuration diagram of a control device of a wire-wound induction machine showing a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram of a control device of the wound induction machine of FIG. 7;

FIG. 9 is a configuration diagram of a control device for a wire-wound induction machine showing a fifth embodiment of the present invention.

FIG. 10 is a configuration diagram of a control device of the winding induction machine of FIG. 9;

FIG. 11 is a configuration diagram of a control device of a wire-wound induction machine showing a sixth embodiment of the present invention.

FIG. 12 is a configuration diagram of a control device of the winding induction machine of FIG. 11;

FIG. 13 is a configuration diagram of a control device of a wire-wound induction machine showing a seventh embodiment of the present invention.

FIG. 14 is a configuration diagram of a control device of the winding induction machine of FIG. 13;

FIG. 15 is an explanatory diagram showing currents between a wound-type induction machine, a frequency converter, and an overvoltage protection device.

FIG. 16 is an explanatory diagram showing the operation of FIG.

FIG. 17 is a configuration diagram of a control device for a wire-wound induction machine showing an eighth embodiment of the present invention.

FIG. 18 is a configuration diagram of a control device for a wire-wound induction machine showing a ninth embodiment of the present invention.

FIG. 19 is a system configuration diagram of a control device for a wound-type induction machine showing a first conventional example.

FIG. 20 is a configuration diagram of a control device of the wirewound induction machine of FIG. 19;

FIG. 21 is a system configuration diagram of a control device for a wire-wound induction machine showing a second conventional example.

FIG. 22 is an explanatory view showing the operation of the control device for the wirewound induction machine in FIG. 21.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding induction machine 2 Transmission line 3 System bus 4 Frequency converter 5 Overvoltage protection device 6 Primary voltage detector 7 Short circuit current detector 8A-8I Frequency converter control unit 8a Primary voltage monitoring means 8b Flip-flop calculation means 8c PI calculation Means 8e Switching means 8e1, 8e2 Switching contact 8f Subtraction means 8g, 8i Addition means 8h Amplitude signal generation means 9A to 9I Sequence control section 9a Timing determination means 9b Active power monitoring means 9c Torque monitoring means 9d Secondary current q-axis component detection means 9e Secondary current q-axis component monitoring means 9f Primary current q-axis component detection means 9g Primary current q-axis component monitoring means 9h Amplitude calculation means 9i Frequency calculation means 9j Short-circuit current prediction means 10 Active power detector 11 Torque detector 12 Secondary Current detector 13 Primary current detector 14 Slip frequency detector 17 Resistance

Claims (10)

[Claims] A primary winding is connected to a system bus, while a secondary winding is AC-excited. A frequency converter that excites the windings and a short-circuit protection of each of the three phases to prevent an overvoltage generated in the three phases between the wound-type induction machine and the frequency converter due to an accident in the system bus. An overvoltage protection device, comprising: a control device for a winding induction machine that controls the frequency converter and the overvoltage protection device, wherein a protection device operation signal indicating a short-circuit protection operation of the overvoltage protection device is input and the frequency conversion is performed. A frequency converter control unit that holds a stop signal for stopping the device and outputs the signal to the frequency converter, and receives an operation permission signal to release the holding of the stop signal; and a short circuit flowing to the overvoltage protection device. Electric When it is determined that the frequency converter can be stably controlled in accordance with the magnitude of the signal or the equivalent signal, a short-circuit release signal for releasing the short-circuit protection operation of the overvoltage protection device and the operation permission signal are output. A control device for a winding induction machine, comprising: a sequence control unit having timing determination means. 2. The timing determining means outputs the short-circuit release signal and the re-operation permission signal when the magnitude of the active power signal output by the spiral induction machine falls below a predetermined value. The control device for a wound-type induction machine according to claim 1. 3. The timing determining means outputs the short-circuit release signal and the re-operation permission signal when a magnitude of a torque detection signal of the spiral induction machine becomes equal to or less than a predetermined value. Item 2. A control device for a wire-wound induction machine according to Item 1. 4. The timing determination means outputs the short-circuit release signal and the restart operation permission signal when a q-axis component signal of a secondary current of the spirally wound induction machine becomes equal to or less than a predetermined value. The control device for a wound-type induction machine according to claim 1. 5. The timing determining means outputs the short-circuit release signal and the re-operation permission signal when a q-axis component signal of a primary current of the wound wire induction machine becomes equal to or less than a predetermined value. A control device for a wound induction machine according to claim 1. 6. The frequency conversion circuit according to claim 1, wherein the timing determining means determines the frequency of the short-circuit current from the slip of the wire-wound induction machine and the magnitude of the short-circuit current obtained from the active power signal of the wire-wound induction machine. 2. The control device for a coiled induction machine according to claim 1, wherein a time when the power becomes equal to or less than a rated power of the transformer is calculated, and when the calculated time is reached, the short-circuit release signal and the restart operation permission signal are output. 7. A winding type induction machine in which a primary winding side is connected to a system bus, and a secondary winding side is AC-excited. A frequency converter that excites the windings and a short-circuit protection of each of the three phases to prevent an overvoltage generated in the three phases between the wound-type induction machine and the frequency converter due to an accident in the system bus. An overvoltage protection device, comprising: a control device for a wound-type induction machine that controls the frequency converter and the overvoltage protection device. A control device for a winding type induction machine, comprising: a frequency converter control unit having a resetting means for zero-crossing so that the current becomes equal to or less than the holding current of the thyristor. 8. The frequency converter control section controls the AC excitation current signal output from the frequency converter to be a current command signal in a normal state, and switches after a short-circuit operation to make the short-circuit current close to zero. And a gain varying means for increasing or decreasing the computing gain of the computing means. The control device for a wire-wound induction machine according to claim 7, wherein the control is performed. 9. The frequency converter control section controls the AC exciting current signal output from the frequency converter to be a current command signal in a normal state, and switches after a short-circuit operation to make the short-circuit current close to zero. And an amplitude signal generating means for generating an amplitude signal having a predetermined width centered on zero, and when the short-circuit current signal becomes close to zero, the amplitude signal generating means 8. The control device according to claim 7, wherein the short circuit current is zero-crossed by adding an amplitude signal. 10. The frequency converter control section controls the AC excitation current signal output from the frequency converter to be a current command signal in a normal state, and switches after a short-circuit operation to make the short-circuit current close to zero. And an amplitude signal generating means for generating an amplitude signal having a predetermined width centered on zero, and the output signal from the calculating means is provided when the short-circuit current signal becomes close to zero. 8. The control device according to claim 7, wherein an amplitude signal is applied from the amplitude signal generating means to cause the short-circuit current to cross zero.