JPH0975780A - Power source for pulse charge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of times of spark discharge generation by making a pulse generator generate impulses so that pulse peak voltage can be kept at a prescribed value or less for a prescribed time at the time when the number of times of spark discharge counted by a counting means exceeds a prescribed one. SOLUTION: In the case spark discharge is generated in an electric precipitator 4, it is detected by a controller 11 in a DC base power source device 1, and also the number of times of the spark discharge is counted. When the number of times of the spark discharge during a prescribed period of time exceeds a prescribed value, a signal to that effect is outputted to a pulse generator 2 for a prescribed time. In this way, the pulse generator 2 lowers pulse spark voltage to a prescribed value or less for a set time to control it so that spark discharge of the electric precipitator 4 can be restrained. The DC base power source for pulse charge 1 performs control so that in the pulse generator 2, pulse charge in which the frequency of pulse voltage generation approaches a set frequency as much as possible can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse charging power supply device applied to a spark discharge control of a pulse charging type electrostatic precipitator.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing a configuration in which a conventional pulse charging power supply device is applied to a pulse charging type electrostatic precipitator. In FIG. 3, 7 is a DC base power supply device, and the output from this DC base power supply device 7 is input to the pulse generator 8. Then, after the pulsed voltage is superimposed on the DC base voltage input by the pulse generator 8, the pulsed voltage is supplied to the electrostatic precipitator (hereinafter referred to as EP) 4. Further, 5 is an interlock wiring, and this interlock wiring 5
Is for sending a signal indicating that the DC base power supply device 7 is in operation to the pulse generation device 8 so that the pulse generation device 8 can be operated under the condition that the DC base power supply device 7 is operated. It is provided. The DC base power supply device 7 includes a thyristor 12 that adjusts the electric power from the single-phase low-voltage commercial power supply 3, a transformer 14 that boosts the adjusted voltage, a rectifier 15 that rectifies the boosted voltage, and a protective reactor 16. It is composed of an EP voltage detector 17 and a control device 71.

FIG. 4A shows the voltage of the pulse charging type EP when performing pulse charging in the above-mentioned configuration.
It is a figure showing a current characteristic. As shown in the figure, the DC high voltage supplied from the DC base power supply device 7 is normally EP4.
Reverse ionization generation voltage (VBC) from the viewpoint of internal reverse ionization suppression
It is set with the lower corona discharge starting voltage (VC) as a guide. Therefore, the output power value of the DC base power supply device 7 is
Only the charging current of EP4. This current value is very small and can be ignored when viewed from the rated current value of the power supply device 7. Further, in order to obtain this voltage / current, the control device 71
As shown in FIG. 4A, the minimum point of the thyristor firing angle signal output from the thyristor is α 0, and it is impossible to adjust the voltage / current to a value lower than this value.

FIG. 4B is a waveform diagram of voltage and current of the pulse charging type EP. During the pulse charging by the above setting, before the pulse peak voltage reaches the set value VPA, E
When a spark discharge occurs inside P4, the DC base power supply device 4 only cuts off the minute charging current described above for a certain time t0, and the pulse voltage is not applied until the voltage of EP4 reaches the set value V0. Therefore, the voltage / current waveform is as shown in FIG.

On the other hand, FIG. 5 (a) is a diagram showing the voltage-current characteristics that are often seen in the recent pulse charging type EP. As shown in the figure, the reverse ionization generation voltage (VBC) is considerably higher than that shown in FIG. 4A because of the change in the gas properties. In this case, the DC base power supply device 7 is operated after the output voltage is set high (VB) to such an extent that the corona discharge current flows to some extent. When a spark discharge occurs in this state, the DC base power supply device 7 detects and counts this discharge, and then interrupts the current for a predetermined time (t0). After that, the current is started to flow again, and the voltage / current until one spark discharge is made and the next spark discharge is made gradually so that the number of spark discharges per unit time (for example, 1 minute) reaches a predetermined set number. It is necessary to increase (however, the degree to which the voltage / current increases depending on the set number of times)
The pulse voltage is not applied until the voltage of 4 reaches the set value V0. FIG. 5B shows a waveform diagram of voltage and current at this time.

The portion in which the pulse voltage is drawn by a broken line in FIGS. 4B and 5B shows a state in which the pulse voltage, which should be superposed, is no longer superposed.

[0007]

If spark discharge occurs during pulse charging operation in the pulse charging type electrostatic precipitator as described above, the following problems will occur. (1) There is a high possibility that a spark discharge will be generated each time a pulse voltage is applied, and it will be difficult to generate ions necessary and sufficient for charging the dust inside the EP4.

(2) When the voltage (VEP) of EP4 falls below a predetermined set value, that is, V0 shown in (b) of FIG. 4 and (b) of FIG. 5 due to the spark discharge, the pulse generator 8 side The pulse generation is stopped for the purpose of preventing the generation of the positive voltage due to the excessive vibration of the voltage when the pulse is generated. For this reason, the number of times the pulse voltage is applied to the EP4 is significantly less than the set value.

The reason why it is necessary to prevent the generation of the positive polarity voltage in the above (2) is that in EP4, when the positive polarity voltage is applied, the negative ions in the dust collector are neutralized, and as a result, the dust collection performance is increased. Is reduced. Further, in the pulse generator 8, the pulse current is suppressed from flowing due to the positive voltage, which may lead to abnormal shutoff of the GTO thyristor and damage to the GTO.

Due to the problems (1) and (2), the pulse voltage is not applied to the EP4 at a predetermined frequency, and the amount of ions generated due to spark generation is reduced, so that the effect of pulse charging is significantly reduced. As a result, the dust collecting performance of EP4 also deteriorates. In particular, the dust collection performance of EP4 remarkably deteriorates in the gas state in which spark discharge is constantly generated and frequently occurs.

It is an object of the present invention to apply a pulse voltage to an electrostatic precipitator at a predetermined frequency, suppress the occurrence of spark discharge, and prevent deterioration of the dust collecting performance of the electrostatic precipitator. To provide a power supply device.

[0012]

In order to solve the above problems and achieve the object, the pulse charging power supply device of the present invention is configured as follows. The power supply device for pulse charging according to the present invention supplies a DC voltage to a predetermined pulse charging type electrostatic precipitator and controls the pulse generation to the pulse charging type electrostatic precipitator by a predetermined pulse generator. In the power supply device for electric power, voltage control means for controlling the DC voltage supplied from the power supply device for pulse charging to be equal to or higher than the corona discharge starting voltage of the pulse charging type electrostatic precipitator, and the voltage is controlled by the voltage control means. When a spark discharge occurs in the pulse charging type electrostatic precipitator during supply, a counting means for counting the number of spark discharges, and a point when the number of spark discharges counted by the counting means exceeds a predetermined number. And instructing means for instructing the pulse generator to generate a pulse by setting the pulse peak voltage to a predetermined value or less for a predetermined period.

[0013] As a result of taking the above measures, the following effects occur. According to the power supply device for pulse charging of the present invention, when the number of spark discharges in the pulse charge type dust collector exceeds a predetermined number, the pulse peak voltage is set to a predetermined value or less for a predetermined pulse generator to generate a pulse. Since it is instructed to do so, the pulse generation stop time in the pulse generator can be shortened, and a decrease in the number of pulse voltage applications can be prevented. Then, by lowering the pulse peak voltage setting value according to an instruction given from the pulse charging power supply device, the pulse peak voltage is also lowered, and the occurrence of spark discharge due to the pulse voltage can be suppressed. Thus, the pulse charging power supply device of the present invention,
A pulse voltage is applied to the electrostatic precipitator at a predetermined frequency, and the occurrence of spark discharge can be suppressed to prevent deterioration of the electrostatic precipitator's dust collecting performance.

[0014]

FIG. 1 is a diagram showing a configuration in which a pulse charging power supply device according to an embodiment of the present invention is applied to a pulse charging type electrostatic precipitator. In FIG. 1, the same parts as those in FIG. 3 are designated by the same reference numerals. As shown in FIG. 1, the present embodiment includes a DC base power supply device 1, a pulse generator 2, a single-phase low-voltage commercial power supply 3 and an EP4. The DC base power supply device 1 includes a control device 11 for performing operation control, a thyristor 12 for adjusting the electric power from the single-phase low-voltage commercial power supply 3, a transformer 14 for boosting the voltage adjusted by the thyristor 12, and a transformer 14. It is provided with a rectifier 15 for rectifying the boosted voltage, a protection reactor 16, an EP voltage detector 17, and a signal generation circuit 18 for generating a signal related to the reduction of the pulse peak voltage set value.

The power source 3 has a terminal 1 of the DC base power source device 1.
The thyristor 12 is connected via 31 and this thyristor 12 is connected to the primary side terminal 141 of the transformer 14. In addition, the power source 3 receives the
Is connected to the primary side terminal 142 of. And transformer 1
The secondary side terminal 143 of No. 4 is connected to the rectifier 15,
The terminal 151 of the rectifier 15 is connected to the pulse generator 2 via the protective reactor 16. Also transformer 1
The secondary side terminal 144 of 4 is also connected to the rectifier 15,
The terminal 152 of the rectifier 15 is connected to the terminal 41 of the EP4 via the EP voltage detector 17, and is grounded outside the DC base power supply device 1.

On the other hand, the control device 1 of the DC base power supply device 1
Reference numeral 1 is connected to the terminals 121 and 122 of the thyristor 12, the EP voltage detector 17, the signal generation circuit 18, and is also connected to the control device 21 of the pulse generation device 2.

The pulse generator 2 includes a controller 21 for controlling the operation and a signal generator 1 of the DC base power supply 1.
8 and a signal processing circuit 22 for generating a signal that lowers the pulse peak voltage by receiving the signal sent from the control unit 21 and the signal processing circuit 22 are connected to each other. The control device 11 of the DC base power supply device 1 and the control device 21 of the pulse generation device 2 are connected by the interlock wiring 5, and the signal generation circuit 18 of the DC base power supply device 1 and the signal processing circuit of the pulse generation device 2 are connected. The wiring 22 is connected to the wiring 22. Further, the pulse generator 2 has a terminal 41 of EP4.
It is connected to the. The terminal 42 of EP4 is grounded.

In the conventional device shown in FIG. 3, when the control devices 71 and 81 are composed of a circuit using a microprocessor, the signal generating circuit 1 shown in FIG.
8. By adding software corresponding to the signal processing circuit 22 to the control devices 71 and 81, respectively, the same DC base power supply device 1 and pulse generator 2 as those shown in FIG.
Can be treated as

Next, the operation of each device configured as described above will be described. First, the control device 1 of the DC base power supply device 1
In No. 1, when the EP voltage detector 17 detects the spark discharge of EP4, the current of EP4 is cut off for a predetermined time, and then the current starts to flow again. At that time, the increase in voltage and current as in the above-mentioned conventional example is stopped, and the current is started to flow at a level such that the voltage value immediately before the spark discharge occurs. Then, the EP voltage detector 1 of the DC-based power supply device 1
In step 7, the spark discharge is detected and counted, and when the count value of the number of spark discharges during a predetermined period exceeds a predetermined value, the control device 11 causes the signal generation circuit 18 to output a signal to the pulse generation device 2 for a predetermined time. . The signal is sent to the signal processing circuit 22 of the pulse generator 2 via the wiring 6, and the signal processing circuit 22 receives this signal to reduce the set value of the pulse peak voltage of EP4 by a predetermined value for a predetermined time. . In addition,
In setting the DC base voltage in the DC base power supply device 1, the voltage-current characteristic of EP4 is acquired in advance, and the reverse ionization start voltage (the voltage at which the characteristic changes from the positive characteristic to the negative characteristic) is grasped and set. I shall.

FIG. 2A is a diagram showing the voltage-current characteristics of the pulse charging type electrostatic precipitator as described above, and FIG. 2B is a voltage and current waveform diagram. In FIG. 2 (a), the DC base voltage (VB) is divided into the corona discharge starting voltage (VC) and the reverse ionization starting voltage (VBC) from the characteristics shown in FIG. 4 (a) and FIG. 5 (a). It is set as a voltage value obtained as a value between. When a pulse voltage is superimposed on this DC base voltage (VB) and a spark discharge is generated inside EP4 during the pulse charging operation, during the period A in FIG. Since it returns to the original level, the pulse voltage is not stopped. Further, since the pulse peak voltage is suppressed during the period B in FIG. 2B, there is no possibility of spark generation. Therefore, by alternately repeating the periods A and B, it becomes possible to perform pulse charging in the vicinity of a predetermined pulse frequency, and it is possible to prevent the performance of the EP 4 from deteriorating due to spark discharge.

FIG. 2C shows a count value (FC) of the number of spark discharges, and when the count value reaches a predetermined set value (FCS), the control device 11 outputs a signal generation circuit. Send a signal to 18. The signal generation circuit 18 sends a signal having a width of a predetermined time (t1) as shown in FIG. 2 (d) to the signal processing circuit 22 of the pulse generation device 2 via the wiring 6 from the time of receiving this signal. Send it. Receiving this signal, the signal processing circuit 22 gives the control device 21 a signal indicating that the set value of the pulse peak voltage is lowered from the VPA level shown in FIG. 2B to the VPA 'level for the predetermined time (t1). Output. Upon receiving this signal, the control device 21
Set the pulse peak voltage of P4 from VP level to VP
Control to lower to A'level.

The present invention is not limited to the above-mentioned embodiments, and can be modified and implemented as appropriate without departing from the scope of the invention. For example, although the single-phase low-voltage commercial power source is used as the power source 3 in the above-described embodiment, the three-phase low-voltage commercial power source may be used.

(Summary of Embodiments) As described above, in this embodiment, in order to supply the DC base voltage of the pulse charging type electrostatic precipitator (4), the single-phase or three-phase low-voltage commercial power supply (3) is used. In the pulse charging DC base power supply device 1 for generating a DC high voltage by adjusting the power from the device, adjusting it to a high voltage, and then rectifying it, the DC high voltage output is equal to or higher than the corona discharge start voltage of EP4 and the power supply device. Operate by setting the rated voltage to 1 or less. When the spark discharge occurs in EP4, the control device 11 in the DC base power supply device 1 detects the spark discharge and counts the number of the spark discharges, and when the number of the spark discharges in a predetermined period exceeds the set value, A signal indicating that is output to the pulse generator 2 for a predetermined time. As a result, the pulse generator 2 reduces the pulse peak voltage for the set period by a predetermined value, and controls so as to suppress the spark discharge of EP4. In this manner, the pulse charging DC base power supply device 1 controls the pulse generator 2 so that the pulse voltage generation frequency is as close to the set frequency as possible.

As a result, after the spark detection and the current interruption are carried out by the DC base power supply device 1, the current is started to flow at a level (> the set value V0) which becomes the voltage value immediately before the spark discharge is generated. As shown in FIG. 2 (b), the DC base voltage recovers quickly and the voltage drop time is shortened. With such an action, the pulse generation stop time in the pulse generator 2 is shortened, and the reduction in the number of times of applying the pulse voltage can be prevented. Further, the pulse generator 2 is a DC base power source device 1
Since the pulse peak voltage setting value is lower than that of the signal sent from the signal generating circuit 18, the pulse peak voltage is reduced and the occurrence of spark discharge due to the pulse voltage can be suppressed. Due to the above-described effects, the pulse voltage is applied to the EP4 at a predetermined frequency, the spark discharge is suppressed, and the deterioration of the dust collecting performance of the EP4 can be prevented.

[0025]

According to the power supply device for pulse charging of the present invention, the frequency of pulse voltage generation during pulse charging can be kept close to the set value even under gas conditions in which spark discharge is generated in the electrostatic precipitator. Since the number of spark discharges can be reduced, the effect of pulse charging can be sufficiently exerted, and the dust collecting performance of the electric dust collector can be significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration in which a pulse charging power supply device according to an embodiment of the present invention is applied to a pulse charging type electrostatic precipitator.

FIG. 2 is a diagram according to an embodiment of the present invention, in which (a) is a diagram showing voltage-current characteristics of a pulse charging type electrostatic precipitator;
(B) is a waveform diagram of voltage and current, (c) is a diagram showing a count value (FC) of the number of spark discharges, and (d) is a signal having a width of a predetermined time (t1) sent to the signal processing circuit. Fig.

FIG. 3 is a diagram showing a configuration in which a pulse charging power supply device according to a conventional example is applied to a pulse charging type electrostatic precipitator.

4A and 4B are diagrams according to a conventional example, in which FIG. 4A is a diagram showing voltage / current characteristics of a pulse charging type electrostatic precipitator when performing pulse charging, and FIG. 4B is a waveform diagram of voltage and current.

5A and 5B are diagrams according to a conventional example, in which FIG. 5A is a diagram showing a voltage / current characteristic of a pulse charge type electrostatic precipitator, and FIG. 5B is a waveform diagram of voltage and current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... DC base power supply device 11 ... Control device 12 ... Thyristor 121 ... Terminal 122 ... Terminal 131 ... Terminal 132 ... Terminal 14 ... Transformer 141 ... Primary side terminal 142 ... Primary side terminal 143 ... Secondary side terminal 144 ... 2 Next-side terminal 15 ... Rectifier 151 ... Terminal 152 ... Terminal 16 ... Protective reactor 17 ... EP voltage detector 18 ... Signal generation circuit 2 ... Pulse generator 21 ... Control device 22 ... Signal processing circuit 3 ... Single-phase low-voltage commercial power supply 4 ... Electrostatic precipitator (EP) 41 ... Terminal 42 ... Terminal.

Claims (1)

[Claims] 1. A power supply device for pulse charging, which supplies a DC voltage to a predetermined pulse charging type electrostatic precipitator and controls the generation of pulses to the pulse charging type electrostatic precipitator by a predetermined pulse generator. Voltage control means for controlling the DC voltage supplied from the pulse charging power supply device to be equal to or higher than the corona discharge starting voltage of the pulse charging type electrostatic precipitator, and when the voltage is supplied by the control of the voltage control means. When spark discharge occurs in the pulse charging type electrostatic precipitator, counting means for counting the number of spark discharges, and the pulse generator when the number of spark discharges counted by the counting means exceeds a predetermined number A power supply device for pulse charging, comprising: an instruction means for instructing to generate a pulse by setting the pulse peak voltage to a predetermined value or less for a predetermined period.