KR200287751Y1 - Pulse generator circuit of electrostatic precipitator - Google Patents

Abstract

The present invention relates to a pulse generating circuit of an electrostatic precipitator, and a pulse having an optimal width and frequency required according to the type and state of gas processed in a conventional electrostatic precipitator should be applied to the electrostatic precipitator. By limiting the minimum width of the pulse generated by the leakage inductance, there is a problem that does not generate the optimum pulse for the various load conditions in the electrostatic precipitator, and also the arc discharge occurs to reduce the dust collection efficiency. Accordingly, the present invention has been made to solve the above-described problems, and by using a plurality of pulse transformers to minimize the total leakage inductance to reduce the minimum width of the pulse, for various load situations inside the electrostatic precipitator At the same time supplying the optimum pulse to prevent the occurrence of arc discharge has the effect of improving the dust collection efficiency. In addition, by using a plurality of pulse transformers having a low boost ratio, the pulse transformer is easier to manufacture than the case of making one pulse transformer having a high boost ratio and there is an effect of reducing the manufacturing cost.

Description

Pulse generator circuit of electrostatic precipitator

The present invention relates to a pulse generating circuit of an electrostatic precipitator, and in particular, in applying pulses to an electrostatic precipitator, a plurality of pulse transformers are used to minimize the leakage inductance of the entire pulse transformer, thereby reducing the width of the pulse, thereby making it suitable for various load situations. A pulse generating circuit of an electrostatic precipitator for generating a pulse of.

A general electrostatic precipitator is a cylinder or plate to which a positive high voltage is applied when a corona discharge is generated in a discharge electrode using a wire to which a negative high voltage is applied to ionize a process gas to charge dust and then form an electric field. The charged dust is collected on a dust collecting plate in the form of to remove the dust particles.

In this case, traditionally, the voltage applied between the discharge electrode and the dust collecting plate is applied with a high voltage DC voltage generated by the high voltage pulse transformer and the rectifier, but the DC voltage has a disadvantage in that dust collection efficiency is reduced for dust having a large resistivity.

Therefore, by varying the pulse frequency by using a pulse application method that maintains the DC voltage below the corona starting voltage and superimposes the high voltage pulse with a short width, the current distribution in the dust collector of the electrostatic precipitator becomes uniform. The dust collection efficiency for dust with a large specific resistance increased compared with the said DC application method, such as the dust charging degree became strong.

1 is a block diagram of a general electrostatic precipitator, as shown therein, a pulse generator 10 for generating and outputting a pulse having a high voltage (30 to 40 kV) and a width of about 100 us; A DC generator 20 for generating and outputting a DC voltage having a high voltage of 30 to 40 kV; A discharge electrode 30 that receives a negative voltage to cause a corona discharge to ionize the processing gas to charge dust and form an electric field; A dust collecting plate 40 for collecting dust charged by applying a positive voltage; The DC voltage of the high voltage of the DC generator 20 is composed of a coupling capacitor (CC) to prevent the inflow into the pulse generator (10).

In addition, the pulse generator 10 includes an inductance (LPS) for limiting a voltage (-VPS) supplied from a pulse supply source (not shown) as shown in FIG. A charging capacitor CS that receives the voltage of the pulse supply source (-VPS) through the inductance LPS and charges a negative voltage; A thyristor T connected to the charging capacitor CS to block a negative current by receiving a control signal; A diode D connected in a reverse direction to the charging capacitor CS to block a positive current; A pulse transformer (PT) connected to a primary side of the thyristor (T) and a diode (D) to apply a pulse to a dust collector; An operation process according to the related art, which is composed of a leakage inductance LS leaking from the pulse transformer PT, will be described in detail with reference to the voltage and current waveform diagrams of FIG. 3.

First, before the pulse is applied, the charging capacitor CS is charged with a negative voltage by receiving the output pulse (-VPS) of the pulse supply source, and the dust collecting capacitor CF of the dust collector composed of the discharge electrode 30 and the dust collecting plate 40. ) Is charged to the output voltage (-VDC) of the DC generator 20.

Here, when the thyristor T is turned on for a positive half cycle, the pulse generator 10 has a series resonance circuit including a charging capacitor CS, a leakage inductance LS, a coupling capacitor CC, and a dust collecting capacitor CF. The furnace is configured, where the current IP (t) flowing through the discharge electrode 30 and the dust collecting plate 40 flows through the thyristor T for a positive half cycle as shown in FIG. 3.

In addition, since the thyristor T is automatically turned off during the negative half period, the diode D is conducted by the energy stored in the leakage inductance LS so that the current IP (t) flows in the opposite direction. do.

After a certain time, the current IP (t) is maintained at 0 until the thyristor T is turned on again, and the interval for turning on the thyristor T is a value corresponding to the frequency of the pulse.

In this process, the voltage waveform VP (t) of the pulse appearing in the equivalent capacitance of the dust collector is shown in FIG. 3.

Here, assuming that the pulse transformer PT is an ideal 1: n pulse transformer PT and the capacity of the charging capacitor CS is very large, the width of the pulse To is , Where ego, to be.

Therefore, the value of the coupling capacitor CC is generally set to about 10 times the dust collecting capacitor CF to minimize the total capacitor amount Ceq to minimize the effect on the circuit.

That is, in the electrostatic precipitator using the pulse transformer PT, the width of the voltage pulse appearing in the electrostatic precipitator is a value determined by the dust collecting capacitor CF and the leakage inductance LS, but in reality, the dust collecting plate 40 is used. When this determination is made, the collecting capacitor CF is automatically determined, so that the width of the pulse is adjusted only by the leakage inductance LS.

Therefore, the leakage inductance LS is a value connected in series to the primary side of the ideal pulse transformer PT. In the actual pulse transformer PT, the pulse width is constant even when the leakage inductance LS is large. It cannot be reduced below.

That is, when applying the pulse having the optimum width and frequency required according to the type and condition of the gas to be processed in the conventional electrostatic precipitator as described above, the pulse generated by the leakage inductance of the pulse transformer Since the minimum width is limited, there is a problem in that an optimal discharge for various load conditions in the electrostatic precipitator is not generated and an arc discharge is generated to reduce dust collection efficiency.

Therefore, the present invention has been devised to solve the conventional problems as described above, and by using a plurality of pulse transformers to minimize the total leakage inductance of the electrostatic precipitator to reduce the width of the pulse to generate the optimum pulse for various load conditions Its purpose is to provide a pulse generator circuit.

1 is a block diagram of a typical electrostatic precipitator.

2 is a pulse generation circuit diagram of a conventional electrostatic precipitator.

3 is a voltage and current waveform diagram of the dust collector in FIG.

4 is a pulse generating circuit diagram of the present invention electrostatic precipitator.

* Description of the symbols for the main parts of the drawings *

10: pulse generator 20: DC generator

30: discharge electrode 40: dust collecting plate

50: pulse transformer PT1 to PT3: pulse transformer

The configuration of the pulse generating circuit of the present invention electrostatic precipitator for achieving the above object includes an inductance for limiting the voltage supplied from the pulse supply source; A charging capacitor configured to charge a negative voltage by receiving the voltage of the pulse supply source through the inductance; A thyristor connected to the charging capacitor to block a negative current by receiving a control signal; A diode connected to the charging capacitor in a reverse direction to block a positive current; A pulse transformer unit for applying pulses to a dust collector using a plurality of pulse transformers having a primary side connected in parallel to the thyristor and a diode side; It is characterized by consisting of a leakage inductance leaking from the pulse transformer.

Hereinafter, with reference to the accompanying drawings, the operation and effect of an embodiment of the present invention will be described in detail.

Figure 4 is a pulse generating circuit diagram of the electrostatic precipitator of the present invention, as shown therein is an inductance (LPS) for limiting the voltage (-VPS) supplied from a pulse supply source (not shown); A charging capacitor CS that receives the voltage of the pulse supply source (-VPS) through the inductance LPS and charges a negative voltage; A thyristor T connected to the charging capacitor CS to block a negative current by receiving a control signal; A diode D connected in a reverse direction to the charging capacitor CS to block a positive current; A pulse transformer unit (50) for applying pulses to the dust collector by using a plurality of pulse transformers (PT1 to PT3) having primary sides connected in parallel to the thyristor (T) and diode (D) sides; Consists of the leakage inductance (LS) leaked from the pulse transformer 50, the operation of the present invention is configured in the same manner as in Figure 2 except for the operation of the pulse transformer.

That is, since the leakage inductance LS of the pulse transformer 50 is equivalent to the parallel sum of the respective leakage inductances LS1 to LS3 of the plurality of pulse transformers PT1 to PT3 connected in parallel to the primary side, the pulse inductance LS is equivalent to the pulse inductance LS. The leakage inductance LS of the transformer unit 50 becomes smaller than the leakage inductances LS1 to LS3 of each of the plurality of pulse transformers PT1 to PT3.

Therefore, since the leakage inductances LS1 to LS3 of the plurality of pulse transformers PT1 to PT3 are connected in parallel to reduce the total leakage inductance LS as desired, the width of the pulse applied to the dust collector is eventually reduced.

In addition, since the secondary side of the pulse transformer 50 connects the secondary side of the plurality of pulse transformers PT1 to PT3 in series, the secondary side inductance of the pulse transformer 50 may include the plurality of pulse transformers ( It is equal to the sum of the secondary inductances of PT1 to PT3).

Accordingly, as the primary inductance of the pulse transformer 50 decreases, and the secondary inductance increases, the boost ratio of the pulse transformer 50 is obtained by adding the boost ratios of the plurality of pulse transformers PT1 to PT3. Will appear.

As described in detail above, the present invention minimizes the total leakage inductance by using a plurality of pulse transformers to reduce the minimum width of the pulse, thereby supplying the optimum pulse for various load conditions inside the electrostatic precipitator and at the same time arc discharge It is effective to prevent the occurrence of the dust collection efficiency.

In addition, the present invention uses a plurality of pulse transformers having a low boost ratio, it is easier to manufacture the pulse transformer than the case of making one pulse transformer having a high boost ratio has the effect of reducing the manufacturing cost.

Claims (1)

An inductance for limiting the voltage supplied from the pulse supply source; A charging capacitor configured to charge a negative voltage by receiving the voltage of the pulse supply source through the inductance; A thyristor connected to the charging capacitor to block a negative current by receiving a control signal; A diode connected to the charging capacitor in a reverse direction to block a positive current; A pulse transformer unit configured to connect the primary sides of the plurality of pulse transformers to each other in parallel to the thyristor and the diode side, and to connect the secondary sides of the plurality of pulse transformers in series to apply pulses to the dust collector; The pulse generator circuit of the electrostatic precipitator, characterized by consisting of a leakage inductance leaking from the pulse transformer.