JP2001200080A - Protective unit for inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely recognize only an inverter necessary to be protected in response to the state of arc discharge occurring between electrodes to thereby stop the operation of the inverter. SOLUTION: The protective unit protects a plurality of independent inverters 31a, 31b which apply a high-frequency voltage to a plurality of electrodes 33a, 33b, installed facing a dielectric roll 35 kept at the earth potential, to cause corona discharge to thereby subject a film (34) conveyed by the rotation of the roll 35 to surface treatment. The protective unit is equipped with a control unit 11 which, when an abnormal state in one of the electrodes 33a, 33b is detected and the operation of the corresponding one of the inverters 31a, 31b is stopped, detects the state of application of voltage from the electrode side to the inverter the operation of which is stopped, thus controlling the operation of the other inverter depending on the results of detection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device for an inverter for generating high-frequency power to cause corona discharge in a device for performing a surface treatment of a film.

[0002]

2. Description of the Related Art FIG. 4 shows a circuit configuration of a general inverter for generating high-frequency power in a device for performing corona discharge for film surface treatment. In the figure, 21 is 3
A rectifying bridge for rectifying the output of the three-phase AC power supply 21; 3, a DC smoothing capacitor; 4, a single-phase inverter bridge; 25, a high-voltage transformer; 6, a control circuit; , 7 are connection lines of the detection circuit,
8 is a reactor.

In the above-described circuit configuration, the three-phase AC output from the three-phase AC power supply 21 which is a commercial power supply is rectified to DC by the rectifying bridge 2 and further smoothed by the DC smoothing capacitor 3. In the inverter bridge 4, the power is excited at a resonance frequency determined according to the load to produce high-frequency power, which is further boosted by a high-voltage transformer 25 before being supplied to a load (not shown).

At this time, the control circuit 6 constantly detects the state through the connection line 7 of the detection circuit, and performs control operations such as judging an abnormality, outputting an alarm, and stopping the operation as necessary.

FIG. 5 schematically shows a surface treatment method using corona discharge. A three-phase AC power supply 21 and a high-voltage transformer (HVTR) 25 are the same as those shown in FIG. INV). Three-phase AC power supply 2
The three-phase AC voltage from 1 is increased in frequency by an inverter 31 and boosted by a high-voltage transformer 25 so that the corona discharge electrode 3
3 is applied.

The corona discharge electrode 33 is disposed on the transport path of the film 34 to be surface-treated at a position facing the roll 35 made of a dielectric material. Mounted.

[0007] Corona discharge is generated between the corona discharge electrode 33 and the roll 35 by high-voltage and high-frequency power, and the energy of electrons during the discharge causes a fine surface of the film 34 passing through the discharge space to be formed. Unevenness is formed as a surface treatment.

[0008]

SUMMARY OF THE INVENTION
The pair of the electrode and the corona discharge electrode 33 is installed in the final step of the production line of the film. When the running speed of the film 34 is increased due to an increase in the production amount or the like, the power required for corona discharge also increases because the surface treatment must be performed in a short passage time. Therefore, in such a case, the output of the inverter 31 for corona discharge has been increased.

However, when considering a high-voltage, high-frequency inverter, increasing the output of a single unit may be disadvantageous in terms of cost. Therefore, it is conceivable to use a plurality of inverters. Even if a plurality of electrodes 33 are provided, the same roll 35 can be discharged, and the installation space can be omitted.

FIG. 6 shows two inverters 31a and 31b.
In addition, two corona discharge electrodes 33a and 33b are installed on a single roll 35 using high-voltage transformers 25a and 25b. With this configuration,
Since the plurality of electrode pairs are connected to different inverters, the frequency, phase, and the like in the discharge can be different.

In order to realize such an arrangement, in response to demands for downsizing of a machine, reduction of a machine installation area in a factory, and the like, a roll 35 having a smaller diameter has been used. In this case, it goes without saying that the plurality of electrodes are arranged with a distance in consideration of insulation between the electrodes.

However, as a protection operation for the inverter 31 as described above, specifically, the following control processing has been performed. That is, the first protection measure is a method of stopping the operation of the inverter 31 itself in response to an overcurrent flowing inside the inverter 31, and the second protection measure is to discharge the electrode with a high voltage electrode. Since an arc discharge may occur from the ground to the ground potential, when the arc discharge occurs, the arc is instantaneously extinguished and the power supply is stopped to protect the equipment.

Here, the second protection measure against arc discharge will be considered.

The output of the inverter 31 is controlled to output the capacitance between the electrodes and the resonance frequency of the reactor 8 inside the inverter 31. However, if an arc discharge occurs to a ground potential or the like, the resonance condition deviates from the resonance condition, so that the output voltage or current phase of the inverter 31 jumps. The control circuit 6 inside the inverter 31 monitors the sudden change in the phase, recognizes that the discharge is abnormal due to the arc, and stops the discharge output.

Inverter 3 having such a protection function
In 1, the following problem occurs. That is, in the configuration having a plurality of corona discharge electrodes 33a and 33b as shown in FIG. 6, the plurality of electrodes 33a and 33b are separated from each other by an insulation distance or more.
Since there is a sufficient separation from the distance from the roll 35, there is almost no possibility of discharge between the electrodes 33a and 33b through the atmosphere in a normal state.

However, when dirt adheres to the surface of the roll 35 or when moisture is condensed, FIG.
At a portion where the film 34 is not interposed between the electrode 33 (33a, 33b) and the roll 35 at the end of the roll 35 as shown in FIG. 7A, for example, as shown in FIG.
<1> in the figure between the electrodes 33a from b through the roll 35
Arc discharge may occur through the path of <3>, and as a result, the arc discharge may directly continue between the electrodes 33b and 33a via the atmosphere.

When such an inter-electrode arc occurs, two inverters 31a, 3 operating in different phases are used.
It is considered that there is almost no possibility that both 1a and 1b suddenly change the phase and determine that the arc is a ground arc and stop the operation.

This means that the two inverters 31
a and 31b supply energy to the inter-electrode arc, and the inverter on the side supplied with energy suddenly changes its phase and stops, but the inverter on the side supplying energy has another Since the arc between the electrodes continues unless the arc is extinguished due to the conditions described above, for example, cooling of the arc, dirt or dew condensation on the surface of the roll 35 disappears, the inverter on the side supplying this energy should continue to operate. This is because such control is performed.

FIG. 8 shows an example of a high-voltage current waveform when an arc is generated between the electrodes by disabling the protection function. An arc discharge is generated at a timing TA in FIG. Then, two inverters 31a, 3
It can be seen that although 1b is operating in a different phase, the two inverters 31a and 31b are almost in phase and continue to operate immediately after the arc is generated.

At this time, if the above protection function is operated,
The inverter whose phase suddenly changes and is supplied with energy by the arc discharge stops its operation, but the inverter that supplies energy whose phase change is small or hardly changes causes a sudden change in phase. Since it cannot be detected, the operation is continued without stopping.

However, if the operation is continued in a state in which arc discharge occurs between the electrodes, the following problem occurs.

FIG. 9 shows a circuit configuration of two inverters 31b and 32a that arc discharge between the electrodes 33b and 33a. Now, it is assumed that an arc is generated between the electrodes 33b and 33a, and the inverter 31a that has detected the arc has stopped operation by the operation of the protection function. Even if the inverter 31a stops operating, the inverter 31b
The arc discharge between the electrodes 33b and 33a continues as long as the operation is performed, and the energy of the arc is reduced by the inverter 31 as shown by the arrow EN in the figure.
b between the electrodes 33b and 33a and the inverter 31
a.

This energy is supplied by an alternating current having a frequency generated by the inverter 31b.
In the supplied inverter 31a, the supplied AC current is rectified by the diode 71, so that the DC voltage of the stopped inverter 31 increases.

When the DC voltage rises in the inverter 31a whose operation is stopped, the voltage applied to both ends of the capacitor and other semiconductor elements connected to the DC circuit of the inverter increases. The element will be destroyed when the withstand voltage of the element is exceeded.

In order to prevent such a situation, when one of the two inverters 31a and 31b detects the arc discharge, the other side that does not detect the arc discharge simultaneously operates simultaneously. By stopping, the arc discharge between the electrodes can be extinguished.

However, when such an interlocking control is realized, the arc flies between the electrode and the ground instead of between the electrodes, and the operation is stopped to protect the inverter that generated the arc. Even if it is desired to do so, since there is no means for distinguishing and recognizing the site where the arc discharge is occurring, the operation of the other inverters discharging to the same roll 35 must be stopped.

The present invention has been made in view of the above circumstances, and an object of the present invention is to apply a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at ground potential. A protective device that protects a plurality of independent inverters by applying a corona discharge and applying a surface treatment to a film delivered by rotation of the roll. It is an object of the present invention to provide an inverter protection device capable of surely recognizing only an inverter that needs to be protected and stopping its operation.

[0028]

According to the first aspect of the present invention,
Applying a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at the ground potential to generate a corona discharge, thereby performing a surface treatment of a film delivered by rotation of the roll. A protection device for protecting each independent inverter, wherein the first device detects an abnormal state at the electrode and stops the operation of the corresponding inverter.
Control means, and second control means for controlling the operation of another inverter in accordance with the state of voltage application or current inflow from the electrode side to the inverter whose operation has been stopped by the first control means. It is characterized by having.

According to a second aspect of the present invention, a corona discharge is generated by applying a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at the ground potential, and the roll is delivered by rotating the roll. A protection device for protecting a plurality of independent inverters for performing a surface treatment on a film to be performed, wherein the first control means detects an abnormal state at the electrode and stops operation of the corresponding inverter; A second control means for controlling the operation of another inverter in accordance with the voltage value in the DC circuit section of the inverter whose operation has been stopped by the first control means.

According to a third aspect of the present invention, a corona discharge is generated by applying a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at the ground potential, and the roll is delivered by rotating the roll. A protection device for protecting a plurality of independent inverters, which is provided for each of the plurality of inverters, detects an abnormal state at the electrodes, and operates the corresponding inverter. A first control unit for stopping the operation, a second control unit provided for each of the plurality of inverters, and detecting a voltage value in a DC circuit unit of the inverter whose operation is stopped by the first control unit; And a third control means for controlling the operation of the other inverters in accordance with the detection content of the second control means.

In any of the first to third aspects of the present invention, it is possible to reliably recognize only the inverter that needs to be protected and stop its operation in response to the state of arc discharge generated at the electrode. It becomes possible.

[0032]

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration. Inverters 31a and 31b, high-voltage transformers 25a and 25b, corona discharge electrodes 33a and 33b, a roll 35, and an earth brush 37 are basically the same as those shown in FIG. Since it is the same as that described in FIG. 9 and the like, the same portions are denoted by the same reference numerals and description thereof will be omitted.

Thus, a voltage detector 12a for detecting a voltage between the inverter 31a and the high voltage transformer 25a is provided, and a voltage detector 12b for detecting a voltage between the inverter 31b and the high voltage transformer 25b is provided. The content is sent to the control device 11.

The control device 11 includes an inverter 31a,
The inverter 31a and the inverter 31b respectively transmit signals 13a and 13b indicating that the own device is operating to the control device 11, and perform an operation from the control device 11 to protect the device 31b. Receive signals 14a and 14b instructing to stop the operation.

In such a configuration, for example, the electrode 33
arc discharge is generated between the inverters 31a and 33b.
Detects this and stops the operation, while the inverter 31b
Consider the operation when driving is continued.

The control device 11, which recognizes that the operation of the inverter 31a has stopped based on the content of the signal 13a from the inverter 31a, determines whether a voltage is generated between the inverter 31a and the high-voltage transformer 25a based on the signal from the voltage detector 12a. Determine whether or not.

In this case, since the operation of the inverter 31a is stopped, the current from the inverter 31b is not supplied to the inverter 31a unless the arc discharge occurs between the electrodes 33a and 33b. Detector 1
No generation of voltage is detected in 2a.

On the other hand, if an arc discharge occurs between the electrodes 33a and 33b, the current from the inverter 31b is supplied to the inverter 31a by the arc discharge, and the voltage is generated by the voltage detector 12a. Can be detected.

Therefore, when a voltage is generated by the signal from the voltage detector 12a corresponding to the inverter 31a on which the operation has been stopped, the control device 11
It is determined that an arc discharge has occurred between 3a and 33b, and the operation of the inverter 31b, which continues to operate, is also stopped by the signal 14b.

As described above, the dielectric roll 35 having the ground potential
Even if an arc discharge occurs between the electrodes 33a and 33b provided for the arc discharge, the arc discharge is forcibly extinguished in order to stop the operation of the inverter 31b which continues to supply current to the arc discharge. be able to.

When an arc discharge occurs not between the electrodes 33a and 33b but between one of the electrodes 33a and 33b and the ground, the inverter connected to the electrode on the side where the arc discharge is generated. Since only 31a or 31b is stopped, without stopping other inverters,
Driving can be continued.

In the above embodiment, the inverter 3
1a and a high voltage transformer 25a, a voltage detector 12a for detecting a voltage between the inverter 31b and the high voltage transformer 25b.
And a voltage detector 12b for detecting a voltage between the electrodes 33a and 33b.
A current detector for detecting the inflow of current from the b side to the inverters 31a and 31b may be provided.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows the circuit configuration. The inverters 31a and 31b, the high voltage transformers 25a and 25b, the corona discharge electrodes 33a and 33b, the roll 35, and the ground brush 37 are basically the same as those shown in FIG. Since it is the same as that described in FIG. 9 and the like, the same portions are denoted by the same reference numerals and description thereof will be omitted.

Thus, a DC voltage detector 82a is provided for detecting a smoothed DC voltage at a stage preceding the inverter bridge 4 in the inverter 31a, and a DC voltage detector 82b is provided for the inverter 31b. Is sent to the control device 81.

The control device 81 includes an inverter 31a,
A control operation for protecting the inverter 31b is performed. In particular, the controller transmits signals 83a and 83b for instructing the inverters 31a and 31b to stop the operation.

The inverters 31a and 31b are connected to the DC voltage detector 8 when the normal three-phase AC power supply 21 is connected regardless of whether the inverter is operating or stopped.
The DC voltage detected by 2a and 82b is a value within a certain width.

In such a configuration, for example, the electrode 33
arc discharge is generated between the inverters 31a and 33b.
Detects this and stops the operation, while the inverter 31b
Consider the operation when driving is continued.

At this time, since the inverter 31a is stopped, the DC voltage detected by the DC voltage detector 82a is:
Normally, the value should be within a certain range. However, due to arc discharge of the electrodes 33a and 33b, the inverter 31b
, The value of the DC voltage detected as a result increases.

In the control device 81, the DC voltage detector 8
Inverter 31a being stopped by the detection signal from 2a
It is determined that the DC voltage has risen, and arc discharge has occurred between the electrodes 33a and 33b, and the inverter 31b that continues to operate is also stopped by the signal 83b.

As described above, the dielectric roll 35 having the ground potential
Even if an arc discharge occurs between the electrodes 33a and 33b provided for the arc discharge, the arc discharge is forcibly extinguished in order to stop the operation of the inverter 31b which continues to supply current to the arc discharge. be able to.

When an arc discharge occurs not between the electrodes 33a and 33b but between one of the electrodes 33a and 33b and the ground, the inverter connected to the electrode on the side where the arc discharge is generated. Since only 31a or 31b stops and its DC voltage does not exceed a certain width value, without stopping the other inverter,
Driving can be continued.

The method of detecting the occurrence of arc discharge between the electrodes from the increase in the DC voltage value according to the second embodiment is implemented together with the method according to the first embodiment. When the occurrence of arc discharge between the electrodes is detected by the method described above, the operation of the inverter on the side where the operation is continued may be stopped.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows the circuit configuration of the circuit.
Reference numerals 31c to 31c denote inverters having basically the same configuration as the inverter 31 described with reference to FIG. 2, and the same portions are denoted by the same reference numerals and description thereof will be omitted.

It is assumed that the control circuit 6 'in each of the inverters 31a to 31c has a function of monitoring the voltage value in the DC circuit even when the operation of the inverter is stopped.

Further, each of the inverters 31a to 31c
The overall control circuit 91 is connected to the control circuit 6 ′ via the communication line 92. The general control circuit 91 is composed of, for example, a sequencer or a personal computer. Control the operation / stop of

In such a configuration, for example, the electrode 33
arc discharge is generated between the inverters 31a and 33b.
Detects this and stops operation, while the inverter 31
b, 31c consider the operation when the operation is continued.

At this time, since the inverter 31a is stopped, the voltage value in the DC circuit portion should normally be a value within a certain width, but due to arc discharge of the electrodes 33a and 33b. Is supplied with the current from the inverter 31b, the DC voltage value increases as a result.

The control circuit 6 'of the inverter 31a transmits to the overall control circuit 91 via the communication line 92 that the value of the DC voltage has risen despite the fact that the operation has been stopped. The integrated control circuit 91 has the electrodes 33a, 3
It is determined that an arc discharge has occurred between 3b or between the electrodes 33a and 33c, and the operation of the inverters 31b and 31c that are continuing operation is also stopped by the communication line 92.

As described above, the dielectric roll 35 having the ground potential
Even if an arc discharge occurs between any of the electrodes 33a to 33c disposed on the inverter, the arc discharge is forcibly applied to stop the operation of the inverter that continues to supply current to the arc discharge. Can be extinguished.

Also, not between the electrodes, but one of the electrodes
When an arc discharge occurs between one and the ground, only the inverter connected to the electrode on the side where the arc discharge occurred stops because the DC voltage does not exceed a certain width. The operation can be continued without stopping other inverters.

It should be noted that the present invention is not limited to the above-described first to third embodiments, and can be variously modified and implemented without departing from the gist thereof.

[0065]

According to any of the first to third aspects of the present invention, a corona discharge is generated by applying a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at the ground potential. In a protective device for protecting a plurality of independent inverters for performing a surface treatment of a film delivered by rotation of the roll, an inverter that needs to be protected in response to a state of arc discharge generated at the electrode. It is possible to reliably recognize only the operation and stop the operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit configuration according to a third embodiment of the present invention.

FIG. 4 is a diagram exemplifying a circuit configuration of an inverter for general corona surface treatment.

FIG. 5 is a diagram showing an outline of a surface treatment method using corona discharge.

FIG. 6 is a diagram showing a configuration of a surface treatment apparatus using two inverters and electrodes.

FIG. 7 is a view showing the principle of generation of arc discharge between electrodes.

FIG. 8 is a diagram exemplifying a high-voltage current waveform when an arc discharge between electrodes occurs.

FIG. 9 is a diagram showing a circuit configuration and energy flows of two inverters in which arc discharge occurs between electrodes.

[Explanation of symbols]

 2 ... Rectifier bridge 3 ... DC smoothing capacitor 4 ... Inverter bridge 6,6 '... Control circuit 7 ... Connection line 8 ... Reactor 11 ... Control device 12a, 12b ... Voltage detector 13a, 13b ... During operation 14a, 14b ... Operation Stop signal 21 ... three-phase AC power supply 25, 25a, 25b ... high-voltage transformer 31, 31a, 31b ... inverter 33, 33a, 33b ... corona discharge electrode 34 ... film 35 ... roll 36 ... corona discharge 37 ... earth brush 71 ... diode 81: control device 82a, 82b: DC voltage detector 83a, 83b: operation stop signal 91: general control circuit 92: communication line

Continuation of the front page (72) Inventor Shinji Sakagami 1F, Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi F-term in Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works 4F073 AA06 BB01 CA21 HA12 5H007 AA17 CC05 CC32 DA06 DB01 DC02 DC05 GA08

Claims (3)

[Claims] 1. A surface treatment of a film delivered by rotating a roll by applying a high-frequency voltage to a plurality of electrodes provided for the same dielectric roll at ground potential to generate corona discharge. A protection device for protecting a plurality of independent inverters, the first control device detecting an abnormal state at the electrode and stopping the operation of the corresponding inverter; and the first control device. A second control means for controlling the operation of another inverter in accordance with the state of application of voltage from the electrode side or the state of current flow to the inverter whose operation has been stopped at step (c). apparatus. 2. A surface treatment of a film delivered by rotating a roll by applying a high-frequency voltage to a plurality of electrodes disposed on the same dielectric roll at ground potential to generate corona discharge. A protection device for protecting a plurality of independent inverters, the first control device detecting an abnormal state at the electrode and stopping the operation of the corresponding inverter; and the first control device. And a second control means for controlling the operation of the other inverter in accordance with the voltage value in the DC circuit of the inverter whose operation has been stopped. 3. A surface treatment of a film delivered by rotating a roll by applying a high-frequency voltage to a plurality of electrodes disposed on the same dielectric roll at ground potential to generate corona discharge. A protection device for protecting a plurality of independent inverters, wherein the first control is provided for each of the plurality of inverters, and detects an abnormal state at the electrode and stops operation of the corresponding inverter. Means, provided for each of the plurality of inverters, for detecting a voltage value in a DC circuit section of the inverter, the operation of which is stopped by the first control means; An inverter protection device, comprising: third control means for integrally controlling the operation of another inverter according to the detected content.