JPH0368465A - Electric power source for electrostatic precipitator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a high voltage power supply device for an electrostatic precipitator, and is particularly suitable for outputting a voltage waveform in which a pulse waveform voltage due to charging and discharging of a capacitor is superimposed on a DC high voltage. This invention relates to a high-voltage power supply device for an electric dust collector.

[Conventional technology]

Generally, in electrostatic precipitators, it is known that when the electrical resistance of dust increases, abnormal discharge called a reverse ionization phenomenon occurs, significantly reducing dust collection performance. This is because if the charged dust attached to the dust collection electrode plate in the dust collection chamber has a high resistance,
Electrical breakdown occurs in the dust layer due to poor charge release in the dust layer, and ions generated by this breakdown neutralize the charge in the dust collection space.

As a countermeasure against such a reverse ionization phenomenon, a pulse charging method and an intermittent charging method have conventionally been adopted for electric concentrators.

The former high-voltage power supply for an electric precipitator uses two power supplies, a DC high-voltage power supply and a pulse power supply, and employs a method in which a pulse waveform voltage is superimposed on the DC high voltage. That is, a charging method is adopted in which a high voltage pulse of several pulses for 7 seconds or more is applied while a DC bias voltage around the corona discharge starting voltage is applied between the discharge electrode and the dust collection electrode of the dust collector. FIG. 8 shows the overall configuration of a conventional electric dust collector power supply device in which such a charging method is adopted.

In FIG. 8, 10 is a dust collector, 12 is a DC high voltage power supply circuit, and 14 is a high voltage pulse generation power supply circuit. The dust collector 10 is composed of a discharge electrode 16 and a dust collection electrode 18.

The DC high voltage power supply circuit 12 is an AC power i1! ! 20, switching thyristor 22, step-up transformer 24, rectifier 2
I will be threatened from 6.

In addition, the high voltage pulse generation power supply circuit 14 has an AC 1N28
, thyristor 30. It is composed of a smoothing capacitor 32, a switching thyristor 33, a diode 34, a coil 35, and a step-up transformer 36.

DC high voltage source circuit 12 and high voltage pulse generation power source circuit 1
4 through a coupling capacitor 38.

In an electric precipitator having such a configuration, a DC high voltage power source 1 is connected between the discharge electrode 16 and the dust collection electrode 18 of the precipitator 10.
A base voltage outputted from the high voltage pulse generator 12 is applied, and a high voltage pulse outputted from the high voltage pulse generation power supply circuit 14 is superimposed on the pace voltage by a coupling capacitor 38 and applied.

That is, the voltage from the AC power supply 20 of the DC high voltage power supply circuit 12 is stepped up by the step-up transformer 24, and then
The current is rectified into direct current and charged as a pace voltage between the discharge electrode 16 and the dust collection electrode 18. On the other hand, a voltage is applied to the gate of the thyristor 30 of the pulse generation power supply circuit 14 to make it conductive, and the capacitor 32 is charged with the voltage from the AC power supply 28 . Next, a voltage is applied to the gate of the thyristor 33 to make it conductive, and at the same time discharge from the capacitor 32, the voltage of the primary winding 1136A of the step-up transformer 36 is changed to the secondary winding by the step-up transformer 36! The voltage is boosted on the 36B side. The voltage boosted by the step-up transformer 36 increases the voltage at the discharge electrode of the electric collector W1 via the capacitor 38. On the other hand, the inductance Ll of the coil 35 of the pulse generation power supply port Vs14 and the inductance L2 of the step-up transformer 36
A resonant circuit is constituted by the capacitance of the capacitor 38 and the capacitance between the discharge electrode 16 and the dust collection electrode 18 of the electrostatic precipitator,
During the next half cycle after boosting the voltage, current flows in the opposite direction through the diode 34 and the voltage drops rapidly. In this way, a pulse waveform voltage (pulse voltage) is applied superimposed on the base voltage.

[Problem to be solved by the invention]

By the way, conventional high-voltage power supplies for electrostatic precipitators have a drawback that ions are not emitted uniformly from the discharge electrode surface because the pulse width of the pulse voltage is long. For this reason, the spark voltage is low, spark discharge is likely to occur, and the dust collection ability is reduced.

Therefore, if you try to shorten the pulse width of the pulse voltage,
di/dt increases, and a heavy load is placed on the thyristor on the negative side. Therefore, in the past, it was possible to shorten the pulse width of the pulse voltage with small-capacity electrostatic precipitators, but with large-capacity electrostatic precipitators, it was impossible to shorten the pulse width because the burden was too high on the si-risk. .

The present invention was developed in view of the above circumstances, and it is possible to shorten the pulse width even in a large-capacity electrostatic precipitator, and furthermore, the ions are uniformly released from the discharge electrode, and the spark voltage is high, making it possible to collect dust easily. Electrical industry that does not reduce capacity! ! The purpose is to propose a power supply device for equipment.

[Means to solve problems]

In order to achieve the above object, the present invention provides a high-voltage power supply device for an electrostatic precipitator that supplies a voltage obtained by superimposing a voltage with a pulse waveform on a high DC voltage to an electrostatic precipitator. A DC high voltage generating means for applying a DC high voltage between a discharge electrode and a dust collection electrode, a means for shaping an AC voltage from an AC power source into a pulse waveform voltage and boosting the voltage, and a boosted output voltage waveform. and a means for applying a voltage having a pulse waveform whose pulse width is compressed by the magnetic pulse compression means between the discharge electrode and the dust collection electrode. It is said that

[Effect]

In the present invention, the DC high voltage generation means is used to generate high voltage. ! A base voltage is applied between the discharge electrode and the collection electrode of the machine. On the other hand, the pulse voltage is magnetically compressed by the magnetic pulse compression means and superimposed on the base voltage. This shortens the pulse width and uniformly releases ions from the discharge electrode.

〔Example〕

Preferred embodiments of a power supply device for an electrostatic precipitator according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the structure of the first embodiment according to the present invention, and the structure of the eighth embodiment is shown in FIG.
The same members or similar members as those of the conventional power supply device for an electrostatic precipitator shown in the figure are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, 10 is a dust collector, 12 is a DC high voltage power supply circuit, and 14 is a high voltage pulse generation power supply circuit. collection ma
12 is composed of a discharge electrode 16 and a dust collection electrode 18.

The DC high voltage power supply circuit 12 includes an AC power supply 111!20, a switching thyristor 22, a step-up transformer 24, and a rectifier 2.
Consists of 6.

Further, the primary side of the high voltage pulse generation power supply circuit 14 includes an AC power supply 20, a diode 31, a smoothing capacitor 32, a switching thyristor 33, a diode 34, an inductor 35, and a step-up transformer 36. Furthermore, a capacitor 40 and a supersaturation reactor 42 are installed on the secondary side. The supersaturation reactor 42 is composed of a toroidal magnetic core 42A as shown in FIG. The toroidal magnetic core 42A is made of a material such as an amorphous alloy or alloy, or ferrite.

In the first embodiment, the pulse voltage is operated at a constant pulse voltage, and the diode 31 rectifies the AC voltage from the AC voltage R28 to charge the capacitor 32 to the peak value of the AC voltage, and the DC voltage of the pulse generation circuit is Obtaining power supply voltage.

In the first embodiment, by appropriately designing the saturable reactor 42 of the magnetic compression circuit based on the capacity of the electrostatic precipitator 10 and the voltage boosted by the pulse transformer 36, the saturable reactor 42 of the magnetic compression circuit is automatically pulsed when an input is received. Performs compression operation. In other words, when the thyristor 33 is turned on, the charge stored in the capacitor 32 flows through the primary side 36A of the pulse transformer, and a boosted pulse voltage appears on the secondary side 36B (the pulse width is 35.37 mm, the pulse transformer It is determined by the inductance of the winding 36 and the capacitance of the capacitor 32, 38, and 40. When this voltage is close to its peak,
The saturable reactor 42 becomes saturated and the resistance approaches approximately zero.

DC high voltage power supply circuit 12 and high voltage pulse generation power supply circuit 1
4 via a general capacitor 38.

According to the power supply device for an electrostatic precipitator according to the present invention configured as described above, the voltage from the AC power supply 20 of the DC high voltage power supply circuit 12 is boosted by the step-up transformer 24, rectified to DC by the rectifier 26, and then discharged. Electrode 16 and dust collection electrode 18
A base voltage is applied between. On the other hand, the AC voltage from the AC power supply 28 of the high voltage pulse generation power supply circuit 14 is rectified by the diode 31 and charged into the capacitor 32.

Next, voltage E+7 is applied to the gate of the thyristor 33 to make it conductive, and the capacitor 32 is discharged, and the voltage of the primary winding 36A of the step-up transformer 36 is increased to the step-up transformer 36.
As a result, the voltage is boosted by the secondary winding 36B (IQ).The boosted secondary current charges the capacitor 4o.When the charging of the capacitor 40 is finished, the current gradually starts to flow to the supersaturation reactor 42, and the input terminal becomes At the peak value, the supersaturated reactor 42 becomes saturated and the resistance value approaches zero.

As a result, the current from the capacitor 4o rapidly flows, and the pulse voltage waveform is compressed. FIG. 3 shows the waveforms of the human power voltage and the output voltage at this time. On the other hand, the inductances L, , L of the coils 35 and 37 of the pulse generation power supply circuit 14, and the inductance L of the step-up transformer 36
', The capacitance of the capacitors 32, 38, 40 and the capacitance between the discharge electrode and the dust collection electrode of the electrostatic precipitator constitute a resonant circuit, and during the next half cycle after boosting, the voltage is passed through the diode 34. The current flows in the opposite direction and the voltage drops suddenly.

In this way, the pulse voltage is charged superimposed on the base voltage. In this way, in the present invention, the pulse generation power supply circuit 1
Since the pulse width is compressed on the secondary side of 4, no burden is placed on the secondary side 33.

FIG. 4 shows a second embodiment of the present invention, in which the combination of a capacitor 40 and a supersaturation reactor 42 is not limited to one stage as in the first embodiment, but can be arranged in multiple stages, for example, as shown in FIG. You can.

FIG. 5 shows another embodiment in which the pulse voltage can be changed, and the charging voltage of the capacitor 32 is adjusted by controlling the phase angle of the thyristor 30, so that the magnitude of the pulse voltage can be changed. In this case, when the voltage appearing on the secondary coil 36B of the pulse generation power supply circuit 14 changes, the timing at which the magnetic compression circuit is saturated also changes. Therefore, as shown in FIG. 6, a current is applied to the other winding of the core 42A using the DC voltage V to bias the core so that the magnetic compression operation starts at the optimum timing even when the input voltage changes. Make it. The DC voltage V is the 51st!1st thyristor 3
0 phase angle control and the magnitude of the biased magnetism is adjusted to correspond to changes in the input voltage of the magnetic compression circuit.

FIG. 7 shows an example of another magnetic compression circuit in which the pulse voltage is changed. As shown in FIG. 7, a trigger circuit 44 is added to the oversaturation reactor 42, and a thyristor 46
The timing is forcibly determined by turning on the trigger current and forcing the trigger current to flow.

That is, when a trigger signal is applied to the thyristor 46, the charge stored in the capacitor 47 flows through the trigger coil through the thyristor 46, and the core 42A becomes saturated.

〔Effect of the invention〕

As explained above, according to the power supply device for an electrostatic precipitator according to the present invention, since the pulse waveform width from the pulse generation means is compressed by providing the magnetic pulse compression child, ions are uniformly emitted from the discharge electrode. Therefore, the dust collection ability will not decrease.

Furthermore, since the pulse voltage waveform is compressed by magnetic compression, the pulse voltage can be gradually raised on the primary side, so there is no burden on the silicon risk. As a result, conventionally it was possible to shorten the pulse width only with a small-capacity electrostatic precipitator, but the present invention has made it possible to supply a pulse voltage with a short pulse width even with a large-capacity electrostatic precipitator.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment according to the present invention, FIG. 2 is a circuit diagram showing a supersaturation reactor of the first embodiment, and FIG. 3 is a characteristic diagram showing input and output waveforms of the first embodiment. FIG. 4 is a block diagram of a second embodiment of the present invention, FIG. 5 is a block diagram of a third embodiment of the present invention, FIG. 6 is a circuit diagram of a supersaturation reactor used in the third embodiment, and FIG. The figure is a circuit diagram of another supersaturation reactor used in the third embodiment, and FIG. 8 is a conventional power supply circuit diagram of an electrostatic precipitator. 1O... Electrostatic precipitator, 12... DC high voltage power supply circuit, 14... High voltage pulse generation power supply circuit, 4
0...Capacitor, 42...Supersaturation reactor. Figure 3 'A 4 b

Claims (1)

[Claims] (1) In a high-voltage power supply device for an electrostatic precipitator that supplies a voltage obtained by superimposing a pulse waveform voltage on a DC high voltage to an electrostatic precipitator, the AC voltage from the AC power source is boosted and rectified, and the AC voltage is increased between the discharge electrode and the dust collection electrode. a DC high voltage generating means for applying a DC high voltage to the
and magnetic pulse compression means for magnetically compressing the boosted output voltage waveform, and the voltage of the pulse waveform whose pulse width has been compressed by the magnetic pulse compression means is applied to the discharge electrode and the dust collection electrode. A power supply device for an electrostatic precipitator, comprising means for applying voltage between electrodes.