JP2665860B2 - Control method of power supply device for ozone generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an ozone generating power supply device using a thyristor bridge type constant current type inverter.

[0002]

2. Description of the Related Art Conventionally, an ozone generator is disclosed in Japanese Patent Publication No. Sho 60-2.
As described in Japanese Patent Application No. 9641 (C01B 13/11) and the like, the configuration is almost as shown in FIG. FIG. 1 shows a block configuration of a power supply device according to an embodiment of the present invention.
1a, 1b, 1c are three-phase AC power supply terminals, 2 is a converter for converting commercial AC of the power supply terminals 1a to 1c to DC, 3
Is a DC reactor for smoothing, and 4 is a constant current type inverter having a thyristor bridge configuration, and includes thyristors 5 to 8 connected in full bridge. 9 is a step-up transformer,
Both ends of the primary winding 9a are connected to the DC output terminal 4 of the inverter 4.
a, 4b. Reference numeral 10 denotes a starter, which outputs the output terminals 4a and 4b of the inverter 4 and the primary winding 9a at the time of starting.
Supply a DC output for thyristor commutation to the connection point.

Reference numeral 11 denotes an ozone generator connected to the secondary winding 9b of the transformer 9. A plurality of discharge tubes 12 made of a dielectric material, for example, glass, and each of the discharge tubes 12 are provided in a grounded cylindrical container. The high voltage electrode 13 is formed by providing a ground electrode 14 facing the high voltage electrode 13.
, An AC high voltage of, for example, 200 to 2000 Hz (hereinafter referred to as a high-frequency high voltage) of the secondary winding 9b is supplied in parallel.

The starter 10 will be described with reference to FIG. 4 of one embodiment of the present invention. A single-phase AC control power supply 16 is supplied to a rectifier 18 via a transformer 17 and the output of the rectifier 18 is controlled. Is supplied to the starting capacitor 20 via the charging current control device 19.

The capacitor 20 has a positive end connected to one end of a primary winding 9a via an output terminal 4a, and a negative end connected to the primary winding 9b via a thyristor switch 21 and an output terminal 4b. Connected to the other end. Then, before starting, the thyristor switch 21 is turned off, and the capacitor 20 is maintained in a charged state.

Next, at the time of starting, 200 to 2000 H supplied to the inverter 4 from a firing control circuit (not shown).
A pair of gate pulses for firing z is first fixed to the gate pulses of thyristors 5, 8 or 6, 7 and inverter 4 is short-circuited. At this time, DC current i ₁ flowing from converter 2 to reactor 3, thyristors 5, 8 or 6, 7 gradually increases due to the constant current action of reactor 3 and reaches a predetermined constant current.

After the current i ₁ reaches the constant current, for example, the gate pulses of the thyristors 7 and 8 and the gate pulses of the thyristors 5 and 6 alternately change from a short-circuit state fixed to the gate pulses of the thyristors 5 and 8. Transition to a changing AC output state. When the gate pulses of the thyristors 5 and 8 first shift to the gate pulses of the thyristors 7 and 8, a discharge gate pulse is supplied to the starter 10 at the same time, and the thyristor switch 9 is turned on by this pulse.

[0008] starting capacitor 20 is discharged by this on, the output terminal 4a from starter 10, the primary winding 9a, flows a current i ₂ of the large pulsed DC output than the current i ₁ to the output terminal 4b. At this time, if there is no accident in the generator 11 or the like and a so-called normal load state, the voltage generated in the primary winding 9a is applied to the thyristor 5 as a reverse voltage, and the thyristor 5 commutates and extinguishes. , 8 are turned on to the thyristors 7, 8 are turned on.

Thereafter, even if there is no DC output from the starter 10, any one of the fired thyristors 7, 8, or 5, 6 is controlled by the voltage of the primary winding 9a every time the gate pulse changes.
One is commutated and the inverter 4 operates at a frequency (200 to 2000 Hz) sufficiently higher than the commercial frequency, and an AC output of a constant current of this frequency is supplied to the primary winding 9 a of the transformer 9. Then, the output of the inverter 4 is boosted by the transformer 9, and the high-frequency high-voltage output is supplied from the secondary winding 9 b to the generator 11.

At this time, the raw material gas, for example, oxygen is supplied to the generator 11 in the vessel, and the silent state based on the high frequency high voltage is applied between the high voltage electrode 13 and the ground electrode 14 of each discharge tube 12 in this oxygen atmosphere. Discharge occurs to form ozone, and this ozone is discharged out of the container.

By the way, electrodes 13 and 14 such as dielectric breakdown of glass (dielectric) are applied to one of discharge tubes 12 of generator 11.
When a short circuit accident (electrode short circuit accident) occurs, current concentrates on the electrodes 13 and 14 of the discharge tube 12 (accident discharge tube) in which the accident has occurred. In the transformer 9, the voltage of the secondary winding 9b disappears and the voltage of the primary winding 9a also disappears and is maintained at zero.

For this reason, even when the starter 10 is operated at the time of starting to discharge the starting capacitor 20 and its DC output is supplied to the primary winding 9 a of the transformer 9, the commutation to the primary winding 9 a is performed. Since no reverse voltage is generated, commutation of the inverter 4 cannot be started.

Further, the starter 10 is controlled by the control of the protection circuit.
When the operation of the inverter 4 is stopped in only a half cycle when the thyristor switch 9 is turned on, current is concentrated only momentarily in the fuse 15 connected to the high voltage electrode 13 of the accident discharge tube 12, and the energy required for fusing is given. Absent. Therefore, even after the operation of the inverter 4 stops, the accidental discharge tube 12
Of the transformer 9 is connected to the secondary winding 9b of the transformer 9,
Even if the accident discharge tube 12 is not disconnected from the power supply and restarts after the operation of the inverter 4 is stopped, the protection circuit operates again and the operation of the inverter 4 stops.

Therefore, in the above publication, a fusing capacitor is provided in parallel with the capacitor 20 before the starting capacitor 20 of the starter 10, and is closed between the capacitor and the capacitor 20 when charging or when an accident occurs. It is described to provide a switch that performs the operation.

When the discharge tube 12 is started in a state where an electrode short-circuit accident has occurred, the switch is closed to discharge a large amount of the discharge energy of the start capacitor 20 and the fusing capacitor in parallel. DC energy is instantaneously supplied to the fuse 15 of the accident discharge tube 12, and the fuse 15 is blown to connect the electrode 13 of the accident discharge tube 12 to the secondary winding 9.
Disconnect from b. In this case, when restarting, the inverter 4
Operates normally, and generates ozone in a state where the generator 11 has disconnected the accident discharge tube 12.

[0016]

In order to cope with an electrode short-circuit accident of the ozone generator 11 by adding a fuse blowing capacitor and a switch to the starter 10 as in the prior art,
There is a problem that the number of parts of the device increases, which makes the device complicated and expensive, and that the control of the switch of the starter 10 and the like are also required, which complicates the control.

The present invention addresses an electrode short-circuit accident of an ozone generator without adding a fuse blowing capacitor and a switch to a starter, and reliably blows a fuse of an accident discharge tube to restart. The purpose is to be able to do it.

[0018]

In order to achieve the above object, in the control method of the power supply device for generating ozone according to the present invention, starting of the discharge tube of the ozone generator in the state of an electrode short-circuit accident in any one of the discharge tubes. At this time, the inverter is controlled to a DC output state, DC energy for blowing is supplied from the inverter to the fuse of the accident discharge tube via the transformer, and the fuse is blown. After the voltage on the secondary side recovers, the inverter is stopped and returned to the state before starting.

[0019]

According to the control method of the power supply device for ozone generation of the present invention configured as described above, when starting in a state where an electrode short-circuit accident has occurred in any of the discharge tubes of the ozone generator ,
Inverter is controlled to the DC output state DC output of that is supplied to the primary winding of <br/> transformer.

Then, sufficient DC energy via the transformer concentrates on the fuse of the accident discharge tube, and the fuse is blown. Therefore, fusing capacitor in starter, without or providing a switch, it devised to control the inverter,
Sufficient DC energy can be supplied to the accidental discharge tube to reliably disconnect the discharge tube from the power supply. Further, the operation of the inverter stops after the fuse is blown and returns to the original state. Therefore, when the inverter is restarted in this state, the inverter starts normally.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. In the ozone generator shown in FIG. 3, each part except the generator 11 forms an ozone generation power supply device.

The starter 10 of the power supply device is configured as shown in FIG. The difference from the prior art is that the primary winding 9 is connected between the output terminals 4a and 4b to which the starter 10 is connected.
The point is that a voltage detector 22 for detecting the voltage return of a is provided. Next, a control method of the inverter 4 and the starter 10 will be described.

First, in a normal state in which the discharge tube 12 of the generator 11 is started in a state where no electrode short-circuit accident occurs, the ignition control circuit controls the thyristors 5 to 5 of the inverter 4.
8 and the thyristor switch 21 of the starter 10 are triggered in a conventional manner. That is, thyristor 5
8 to the gate pulse P ₅ ~ shown in the FIG. 2 (c) ~ (f)
Supplying a gate pulse P ₂₁ shown in (g) of FIG thyristor switch 21 supplies the P _8.

Therefore, at the time of starting, first, the thyristors 5 and 8 are turned on by the supply of the periodic gate pulses P ₅ and P ₈ , and the output of the inverter 4 is short-circuited. The current i ₁ flowing through the thyristor 4 becomes a short-circuit current passing through the thyristors 5 and 8. At this time, the current i ₁ is supplied to the reactor 3 as shown in FIG.
And gradually increases to reach a predetermined constant current.

Further, the gate pulse P ₂₁ is supplied to the thyristor switch 21 at t _s when the supply of the gate pulses P ₅ and P _{8 is changed to} the supply of the gate pulses P ₇ and P ₈ based on a timer operation or the like. 21 is turned on to discharge the starting capacitor 20, and the primary winding 9a
Supplying a large current i ₂ pulsed shown in (a) of FIG. 2.

At this time, the thyristor 5 is commutated and extinguished by the voltage of the primary winding 9a and is turned off. By this turning off, the thyristor 7, the output terminal 4b, the primary winding 9a and the output terminal 4 are turned off.
a, a negative current (load current) i ₃ flows through the thyristor 8;
The inverter 4 is AC-activated. After that, inverter 4
Are alternately changed to pulses P ₅ and P ₆ and pulses P ₇ and P ₈ at the period τ of the AC output of the inverter 4.

At this time, the fired thyristor 8 or 5 is activated by the voltage generated in the primary winding 9a every time the gate pulse changes.
There are commutation-turn off, the current i ₃ positive as shown in FIG. 2 (b), negatively changed alternately, the inverter 4 generates an AC output which is constant current control. The high-frequency high voltage of the secondary winding 9b, which boosts the AC output, causes the generator 1
1 is driven to generate ozone.

Next, one of the discharge tubes 1 of the generator 11
At the start of a state where the electrodes short-circuit accident 2 occurs, the firing control circuit of the gate pulse P ₅ ~P _8, P ₂₁ in FIG. 1 (c) ~ (f) , the control as shown in (g) I do. That is, initially, as in the normal state, the gate pulses P ₅ and P ₈ are supplied, the thyristors 5 and 8 are turned on, the output of the inverter 4 is short-circuited, and the current i ₁ is turned into a short-circuit current.

At this time, as shown in FIG. 1A, the current i ₁ increases as in the normal state and reaches a predetermined constant current.
Further, the gate pulse P _5, the switching switched t _s to the supply of the gate pulse P _7, P ₈ from the supply of P _8, the thyristor gate pulse P ₂₁ as shown in (g) in FIG. 1 the switch 21
To the primary winding 9a from the starter 10 in FIG.
It pulsed supply a large current i ₂ of shown.

At this time, based on the electrode short-circuit accident of the generator 11, the transformer 9 hardly generates a voltage in the secondary winding 9b and the primary winding 9a, so that a so-called voltage disappearance state occurs. Then, for example, when the voltage disappearance state of the primary winding 9a is detected based on the detection voltage of the voltage detector 22, the inverter 4 is immediately stopped by the protection circuit in the related art, but in this embodiment, the inverter 4 is stopped by the ignition control circuit. Is kept in a DC output state.

[0031] Then, the gate pulse P ₅ to t _{s + 1} that has elapsed since t _s tau as shown in the FIG. 1 (c), (d) , P
₆ is not output, and as shown in (e) and (f) of FIG.
Gate pulses t ₇ and t ₈ are output at t _{s + 2} after elapse of τ from _{s + 1} , and thyristors 7 and 8 are kept on. At this time,
The current i ₃ supplied to the primary winding 9a is, as shown in FIG. 1B, a thyristor 7, an output terminal 4b, a primary winding 9
a, a negative DC current (short-circuit current) flowing through the output terminal 4b and the thyristor 8.

Further, during the occurrence of the electrode short-circuit accident, since the secondary winding 9b is kept in a state where the voltage disappears, for example, several hundreds
The transformer 9 does not enter the magnetic saturation state for a long time of msec to several seconds, and the short-circuit current of the primary winding 9a is reduced to the secondary winding 9b.
Is supplied to the generator 11 via the. With this supply, the fuse 15 of the accident discharge tube 12 is supplied with sufficient DC energy and is reliably blown, and the accident discharge tube 12 is disconnected from the power supply device.

When the accident discharge tube 12 is cut off,
The voltages of the secondary winding 9b and the primary winding 9a return and rise. At this time, based on the rise in the detection voltage of the voltage detector 22, stops the supply of the gate pulse P ₅ to P _8, is returned to the original state of the startup standby stops the inverter 4.

Thereafter, when restarting, since the accidental discharge tube 12 is disconnected, the control and operation in the normal state are performed, and the generator 11 operates normally. The output capacity and the like of converter 2 are set such that current i ₁ when disconnecting faulty discharge tube 12 is large enough to blow fuse 15.

[0035]

Since the present invention is configured as described above, the following effects can be obtained. At the time of starting in a state where an electrode short-circuit accident occurs in any one of the discharge tubes 12 of the ozone generator 11, the inverter 4 is controlled to a DC output state, and sufficient for fusing based on the DC output of the inverter 4. > Since DC energy is supplied to the fuse 15 of the accident discharge tube 12 via the transformer 9 and the fuse 15 is reliably blown, a blower capacitor and a switch may be added to the starter 10 as in the conventional case. Instead, the accident discharge tube 12 can be reliably and simply separated from the power supply at a low cost simply by devising the control of the inverter 4.

Further, when the fuse 15 of the accident discharge tube 12 is blown and the voltages on the primary side and the secondary side of the transformer 9 recover, the inverter 4 stops and returns to the state before starting.
After the accidental discharge tube 12 is disconnected, it can be restarted immediately.

[Brief description of the drawings]

FIGS. 1A to 1G are timing charts for explaining control at the time of starting in an accident occurrence state according to an embodiment of the present invention.

FIGS. 2A to 2G are timing charts for explaining control at the time of normal startup according to one embodiment of the present invention.

FIG. 3 is a block diagram of an ozone generation power supply device according to one embodiment of the present invention.

FIG. 4 is a detailed block diagram of a part of FIG. 3;

[Explanation of symbols]

 4 Constant Current Inverter 9 Transformer 9a Primary Winding 9b Secondary Winding 10 Starter 11 Ozone Generator 12 Discharge Tube 13 High Voltage Electrode 14 Ground Electrode 15 Fuse

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Komuro 2-14-3 Awaji, Higashiyodogawa-ku, Osaka-shi Inside Sansha Electric Manufacturing Co., Ltd. (56) References JP-A-54-26291 (JP, A) JP 60-29641 (JP, B2)

Claims (1)

(57) [Claims] 1. A dc output for commutation of a thyristor of a starter is supplied to a connection point between a constant current type inverter having a thyristor bridge configuration and a primary winding of a step-up transformer at the time of starting. Starting the commutation, boosting the AC output of the inverter by the transformer,
A method of controlling a power supply device for ozone generation, wherein a boosted AC output of a secondary winding of the transformer is applied in parallel between opposed electrodes of respective discharge tubes of an ozone generator via a fuse for each discharge tube, at the start of either of the electrodes short circuit state of each discharge tube, and controls the inverter to the DC output state, the Invar
From data via the transformer to supply DC energy for fusing the fuse accidents discharge tube, blown fuses <br/> the accident discharge tube by direct current energy, fuse blowing of the accident discharge tube By the transformer
A method of controlling a power supply device for generating ozone, characterized in that after the voltages on the secondary side and the secondary side are recovered, the inverter is stopped and returned to a state before starting.