JPH1084681A - Pulse feed device for electrostatic dust collecter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a small pulse width and obtain a pulse or a pulse train having a high pulse-repetition frequency, by using a semiconductor switch and a pulse generating unit having one magnetic switch on the positive side. SOLUTION: A first power supply unit 1 supplies intermediate circuit voltage uC1(t) to an intermediate circuit capacitor C1 for pulse generation at its own output ends 2, 2'. A pulse generating unit fed from the power supply unit 1, 1 contains a series circuit comprising a semiconductor switch T1, a resonance coil L1 and a resonance capacitor C2 , in parallel with the output ends 2, 2' for the power supply unit. The resonance capacitor C2 is connected with the first terminal on a non-linear magnetic switch L2 . The second terminal on the magnetic switch L2 is connected with the output end1 3 of the pulse generating unit. The reflux of energy is achieved through a diode DI and a second resonance coil L2 . Resistors R1 , R2 supply low direct-current voltage lower than the corona starting voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for supplying a pulse power to an electrostatic precipitator.

[0002]

BACKGROUND OF THE INVENTION Electrostatic precipitators (EPS) are used to clean smoke gases, for example, from coal-fired power plants. An electrostatic precipitator is basically 400 parallel to each other.
It is composed of two large-area, rectangular, grounded metal plates provided at an interval of mm to 500 mm. Between these two plates is a helical counter electrode having a high, negative voltage and releasing the negative corona. The smoke gas particles are charged and separated. The electrostatic precipitator is a capacitor having a dielectric which is electrically nonlinear and has a large loss. The static characteristic curve is, for the time being approximated, comparable to the forward characteristic of the diode, the corona onset voltage corresponding to the rising voltage of the diode.

[0003] Smoke gas purifiers when a high, negative DC voltage is applied have a particularly simple and inexpensive structure. Because the robust power supply required for this is essentially a simple 50 Hz three-phase AC regulator,
This is because it is composed of a three-phase high-voltage transformer and a secondary-side bridge rectifier.

When the soot particles are coarse, good filtration efficiency (Ab-scheidegrad) is usually obtained in this voltage mode. In the form of fine granules, and thus into the lungs, causing cancer,
Separation of smoke gas particles of about 0.5 μm in size is almost impossible or even very costly depending on the applied DC voltage.

[0005] At the very high voltages required for the separation of fine smoke gas particles, usually above 100 kV, it must be taken into account that voltage encroachment usually occurs on the load side. This leads directly to the interruption of the separation process. In this case, the smoke gas may reach the atmosphere through the chimney without being filtered for a short time, or a multi-stage dust collector is inevitably required.

Furthermore, even in the case of a plant to which a DC voltage is applied, even in the case of a large furnace apparatus, the power consumption is about 0.02% of the total installed capacity of the power plant. High operating costs are involved.

This can be prevented relatively well by supplying pulses with a pulse width of approximately 50 μs to 100 μs. A short pulse causes a voltage cloaking on the load side only at peak voltages much higher than with an applied DC voltage. For this reason, with such a voltage configuration, a relatively high filtration efficiency can be achieved, even with fine smoke gas particles. Furthermore, the required power according to the pulse shape and pulse width of the voltage on the load side is significantly smaller than when a DC voltage is applied. For example, Herbert J. Hall,
History of pulsed electrification in electrostatic precipitation, Journal of Electrostatics, 25
Vol. 1, No. 1, pp. 21-21, June 1990 or as detailed in W. McCulvein, publisher and editor-in-chief, Pulsed Currents, Preship Newsletter, 216, January 1994. In addition, this type of charging method is widespread.

[0008] The conventional pulse power supply device is usually composed of two DC voltage power supply units and one pulse generation unit. The low power first power supply unit supplies a DC voltage that is typically slightly less than the corona onset voltage. The second power supply unit first supplies a DC voltage for the intermediate circuit. A pulse is finally generated by a post-directly coupled or potential-separated pulse generating unit, which is superimposed on the DC voltage of the first power supply unit.

In the case of a directly coupled pulse-generating unit, the second power supply supplies a high intermediate circuit voltage of, for example, 70 kV. The semiconductor switches required to initialize the pulse are typically designed as a thyristor cascade with up to 100 serially connected elements. A pulse is finally formed by a simple resonant circuit and a cascade of energy return diodes arranged in parallel with the thyristor switch. A balance is provided by a correspondingly sized linear network so that an even voltage division can be ensured in the thyristors connected in series.

However, the more thyristors are connected in series, the more difficult it is to achieve balance. For this reason, the maximum value of the load voltage is typically 80
less than kV.

In other cases, at a lower voltage level of, for example, 10 kV, a pulse is generated by a few thyristors connected in series and is raised to the desired higher voltage level by a pulse transformer. In this case, the thyristor has a possible disadvantageous ratio between the peak current load and the average value. For this purpose, a large-capacity semiconductor switch is required. Such semiconductor switches are known from traction drives, although here very little power is switched. Similar considerations apply for pulse transformers. That is, the pulse current is 400 Hz based on its extremely high amplitude and small pulse duration.
Has a broad frequency spectrum for the ordinary repetition frequency of This has to be regarded as disadvantageous, in particular, in sizing the transformer and leads to an increase in the power dissipation due to the skin effect. In addition, the resulting transformer power due to the pulsed power is a disturbing noise pollution for humans of 110 dB or more. It costs money,
Noise containment is absolutely necessary in this case.

A pulse power supply having individual pulses (so-called single pulse power supply) or a pulse power supply having a pulse train (so-called multi-pulse power supply)
Is commercially available. For example, as reported by C. Maurisson, K. Paul, M. Kirsten, and pulsed current experiments on dust collectors in a wide range of processing and operating conditions (3. ICESP, Padua, 1987),
In each case, the maximum achievable filtration efficiency depends on the pulse shape and
Depends on the composition of the smoke gas.

A schematic diagram of a commercially available single-pulse power supply with a pulse transformer is described, for example, in the aforementioned Electrostatics Genial,
The history of the pulse current of electrostatic precipitation, 25 volumes, can be read from FIG. A directly coupled multi-pulse feeder is shown in the same article in FIG. With this very simple circuit (only five high voltage components), a second power supply unit for low DC current is not required. The function of this power supply unit is performed by a simple resistor. The intermediate circuit capacitor (resonant capacitor) C is selected such that its capacitance is approximately the same as the parasitic capacitance of the dust collector.

As shown in the first scientific studies, the achievable filtration efficiencies, in particular, small dust particles (eg <
0.5 μm) can be further increased
It is time to further reduce the pulse width of currently at least 50 μs. However, since this is no longer possible even with a quick thyristor cascade, another concept, at least another semiconductor switch, is needed. The semiconductor switch prevents the thyristor's principle-based drawbacks (eg safety times to observe).

In principle, the use of an IGBT power module is conceivable here. Nevertheless, in the case of a direct connection, a large number of such power modules are connected in series, based on IGBTs available on the market today and having a maximum reverse voltage of 2 kV, and the current amplitude and current A number of power modules would also have to be connected in parallel based on an unfavorable ratio to the average. Furthermore, the IG connected in series
As is well known, BT control is very costly.
Thus, in the case of the circuits known today, the use of semiconductors that switch quickly can provide particularly economic reasons.

According to other concepts introduced by Mazda (references cited above, Electrostatics Journal, history of pulsed energization of electrostatic precipitation, Volume 25, page 18 and FIG. 8):
The rotation of the spark gap results in a pulse width of less than 1 μs. However, proposals for such a solution based on a perceivable mechanical configuration are rather beneficial for experimental testing. Commercialization of the proposal for this solution is not possible, especially for cost reasons.

Proposals for other solutions are described, for example, in EP 0 417 7
71 B1 is found in FIG. Here, the combination of two series-connected magnetic switches (the principle of a series pulse compression circuit) results in an immediate switching process. In this case, the actual semiconductor switch functions only as an intermediate element and is necessary for pulse initialization. However, the circuit shown in EP 0 417 771 B1 is very expensive and therefore expensive. This is because a large number of high voltage-resistant and high-capacity components are required (primary thyristor cascade with energy return diode cascade, pulse transformer, three pulse-resistant high voltage capacitors, additional Two magnetic switches having a control winding, an energy return diode on the primary side, a power supply unit for the control winding, etc.). As will be more directly appreciated, the components used need to be adjusted very precisely to one another. This is because, without adjustment, the actual functioning of the circuit can no longer be guaranteed (for example, when a capacitor connected in parallel on the secondary side is no longer completely discharged after the switching process, Pulse transformer saturation).

These basic principles of magnetic switches, known since decades, are best suited for the economical generation of very short pulses. This has already been proven many times, especially in the case of pulsed power supplies for high-performance lasers. In contrast, in the case of dust collectors, this rugged circuit has not yet been able to penetrate itself. Because of the high power demands, for example 20-30 kW, of pulsed power supply and the various operating conditions, the concepts proposed to date are very limited, if not appropriate or appropriate for the application. It is because it becomes.

[0019]

It is an object of the present invention to be able to be manufactured in an economical way, for example to allow for very short pulse widths of less than 10 μs and, depending on the composition of the smoke gas particles, to be greater than 100 kV. Several kHz at peak voltage
The present invention is to provide a pulse power supply device for an electrostatic precipitator, which enables a simple pulse or a pulse train having a sufficiently high pulse repetition frequency up to the following.

[0020]

SUMMARY OF THE INVENTION The object of the present invention is to provide a high pulse frequency, a small pulse width of less than 10 μs,
A device for supplying a pulse to an electrostatic precipitator that enables multi-pulse operation, single-pulse operation or quasi-multi-pulse operation when the pulse voltage amplitude is greater than 0 kV, a) applied from an AC voltage network A power supply unit for applying an intermediate circuit voltage to an output terminal and an intermediate circuit capacitor connected in parallel to the output terminal; and b) a pulse generation unit. B1) The pulse generation unit is connected in parallel to the intermediate circuit capacitor. And a series circuit consisting of a first resonance coil, a semiconductor switch, and a resonance capacitor; b2) including exactly one magnetic switch, wherein a first terminal of the magnetic switch has a semiconductor switch and a resonance capacitor. The second terminal of the magnetic switch is connected to the output terminal of the pulse generating unit for connecting the dust collector. B3) The pulse generating unit is connected in parallel with the first resistor, includes a series circuit including a diode and a second resonance coil, and capable of returning energy, and b4) for a power supply unit. And a second resistor connected in parallel with the magnetic switch, the resistors being connected between the output of the first pulse generator and the output for the pulse generating unit, the resistors being connected during the pulse pause. A device for generating an almost constant low DC voltage below the corona starting voltage, generating a multi-pulse with a very short pulse duration, and supplying a pulse power to the electrostatic precipitator; A power supply unit applied from a network to apply an intermediate circuit voltage to an output terminal and an intermediate circuit capacitor connected in parallel to the output terminal; b) a pulse generation unit; b1) the pulse generation unit B2) includes a series circuit including a semiconductor switch, a first resonance coil, and a resonance capacitor, which are connected in parallel to the intermediate circuit capacitor, and b2) includes exactly one magnetic switch. The terminal is connected to a connection point between the first resonance coil and the resonance capacitor, and the second terminal of the magnetic switch is connected to the first terminal of the second resonance capacitor and the first terminal of the third resonance coil. The second terminal of the second resonance capacitor is connected to a reference pole that is connected through between the input and output terminals of the pulse generation unit, and the second terminal of the third resonance coil is connected to the second resonance capacitor. The second terminal is connected to the output terminal of the pulse generation unit. B3) The pulse generation unit is further connected in parallel to the magnetic switch and the third resonance coil, and has the second resistance resistor and the pulse generation unit. Include an output terminal a first resistor which is connected to the output terminal of the power supply unit of use, and it is possible to generate a multi-pulse of very short pulse duration,
A device for pulse feeding an electrostatic precipitator using a pulse transformer for potential separation, comprising: a) an intermediate voltage between an output terminal and an intermediate circuit capacitor connected in parallel to the output terminal, which is applied from an AC voltage network; A power supply unit for applying a circuit voltage; b) a second power supply unit for applying a low DC voltage applied from an AC voltage network or from an output terminal of the first power supply unit, the output terminal of a pulse generation unit. And c) a pulse generating unit having a pulse transformer, c1) the pulse generating unit being connected to the output of the first power supply unit. And a series circuit comprising a first semiconductor switch, a primary winding of a pulse transformer, and a second semiconductor switch, and a demagnetizing diode. C2) the pulse generating unit comprises on the secondary side a series circuit consisting of a mediating diode and a first resonant coil, the mediating diode being the beginning of the winding of the secondary winding of the pulse transformer And the resonance coil is connected to the first terminal of the first resonance capacitor and the first terminal of the magnetic switch, and the second terminal of the magnetic switch is connected to the first terminal of the fourth resonance coil. And a second terminal of the second resonance capacitor, a second terminal of the fourth resonance coil forms a first output terminal of the pulse generation unit, and a winding end of the secondary winding. Are respectively connected to the second terminal of the resonance capacitor and the second output terminal of the pulse generation unit. C3) In the pulse generation unit, the resistor is connected to the output terminal of the pulse generation unit, the first resonance coil and the magnetic switch. Connection point between Combining the is solved by.

Advantageous configurations of the invention are described in the other dependent claims.

The device of the present invention has a number of advantages.

A) The pulse generating means, in the non-potential separation version, comprise only a combination of a conventional semiconductor switch (for example in a thyristor cascade) and exactly one magnetic switch.

B) The pulse generating means has a minimum possible number of high-voltage and pulse-tolerant components (for which, in particular, EP 0 417 771 B1, see FIG. 1).

C) Despite the very short pulse on the load side, for example <10 μs, the semiconductor switch of the pulse generating means has a small amplitude, eg 150 to 20
A current having a high pulse width of 0 μs is applied. Therefore, a low power, particularly inexpensive semiconductor switch can be used.

D) In the non-potential isolation version, the reverse voltage load on the semiconductor switch and the energy return diode cascade is significantly less than in the conventional concept. This is because, in the case of a lossless component, a so-called voltage doubler results at the load.
With the same intermediate circuit voltage, the peak voltage on the load side, which can eventually be achieved, is significantly higher than with the conventional concept.

E) For switching, a thyristor and a GTO
Alternatively, an IGBT or MCT that switches immediately can be used. This is because the ratio between the pulse width and the pulse current amplitude obtains a value that is significantly more preferable than that of the conventional pulse power supply device.

G) The required intermediate circuit DC voltage or low DC voltage can be generated by a highly dynamic, especially small-capacity, switched power supply unit, for example in a resonant circuit.

H) A second power supply unit for applying a low DC voltage is not absolutely necessary. Inexpensive ohmic resistors fulfill this task during pulse pauses.

I) With a very simple circuit enlargement, the time of energy return can be influenced appropriately. Thus, the pulse width required for optimal separation can be determined.

J) The circuit is suitable for single-pulse operation and multi-pulse operation, depending on the embodiment. Quasi-multi-pulse operation is also possible. In this case, the pulse pattern (a plurality of directly consecutive pulses, then a pulse pause) is preset by a corresponding control by the microprocessor. The pulse pattern is formed in this case such that the highest possible filtration efficiency is achieved.

K) Voltage crossing on the load side, unlike in the case of conventional circuits, does not lead to a direct interruption of the power supply unit and thus also to an interruption of the disconnection process. This is because when an arc occurs, the semiconductor switch has already been opened again. Immediately after the arc disappears, a new pulse begins again. The semiconductor switch is thus reliably protected against short-circuit currents.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the means according to the invention for pulse feeding the electrostatic precipitator 4. Starting from, for example, a three-phase AC voltage generated from an AC voltage network AC, the first power supply unit 1.1 has at its output terminals 2, 2 '
The intermediate circuit voltage uC1 (t) is supplied to an intermediate circuit capacitor C1 for pulse generation. In this case, the power supply unit 1.1
Can be designed, for example, as highly dynamic and small capacity switched power supply units in resonant circuits. The switching power supply unit need not be described in further detail. Of course, a conventional 50 Hz power supply unit can also be used. An additional power supply unit for supplying a low DC voltage is not always necessary in this variant.

The power supply unit 1.1 supplies power to the pulse generation unit. This pulse generating unit has a series circuit composed of a semiconductor switch T1, for example, a thyristor cascade, a resonance coil L1 and a resonance capacitor C2, in parallel with the output terminals 2 and 2 'for the power supply unit.

The resonance capacitor C2 is connected to the first terminal of the non-linear magnetic switch L2. Magnetic switch L
The second terminal 2 is connected to the output 3 of the pulse generating unit. The non-linear magnetic switch L2 is designed as a saturable iron core with a winding. Diode D
Energy can be recirculated by the first and second resonance coils L3. By setting the size of the resonance coil L3 accordingly, the time for the return of energy can be favorably influenced. Resistors R1 and R2 provide a substantially constant low DC voltage below the corona onset voltage during the pulse pause. Therefore, no additional power supply unit is required. Furthermore, the resistor R2 provided in parallel with the magnetic switch L2 is an important issue, namely, during the pulse pause,
Another problem is that the difference between the voltage at the resonance capacitor C2 and the voltage at the electrostatic precipitator 4 connected to the output terminals 3, 3 'is equalized again as quickly as possible. Thus,
What can always be guaranteed under any operating conditions is the voltage at the resonant capacitor C2 and the electrostatic precipitator 4.
The magnetic switch L2 is controlled to be turned on again when the difference between the voltages at V.sub.1 and V.sub.2 is not equalized and possibly remains.

The method of operation of the device shown in FIG. 1 is further described below. A typical course of the voltage uDP (t) at the outputs 3, 3 'during single-pulse operation is shown in FIG. FIG. 8B shows a typical transition of the voltage uDP (t) during the quasi-multi-pulse operation.

A second embodiment is shown in FIG.
In this variant, contrary to the device shown in FIG. 1, no additional resonant coil for returning energy is required. However, the resonant coil L13 used in FIG. 2 generally has two windings N1, N2 having different numbers of turns. By changing the turns ratio of the windings N1, N2, the time for the return of energy can be affected, corresponding to the arrangement of FIG.

The variant shown in FIG. 3 is particularly simple, that is to say it is composed of a small number of components. This is because the second resonance coil and thus also the second winding (see FIG. 2) have been omitted. This device differs from the first two variants in that the time for energy return cannot be changed. However, depending on the application, this inexpensive device is quite sufficient for the achievable separation results.

FIGS. 4 and 5 show a pulse generator corresponding to the apparatus shown in FIG. However, in this case, the capacitor C0 is provided for supplying a low DC voltage, and no potential separation occurs. In the device shown in FIG.
The additional power supply unit 1.2 is directly connected, for example, to a three-phase line voltage. In the device shown in FIG. 5, on the other hand, the required energy is supplied directly from the intermediate circuit or, although not explicitly shown in FIG. 5, via the second output of the first power supply unit 1.1. Or by an additional winding wound on the coil L1. The control of the second power supply unit 1.2 can be performed using an optical fiber tube for transmitting control signals. In other cases, there is usually a high demand for insulation, and measures are needed to fulfill this demand, but in this case no such measures are necessary. Of course, the devices shown in FIGS. 1, 2 and 6 and 7 are also suitable as variants as shown in FIGS. However, this is not pointed out again in detail below.

Another variation of the non-potential separation is shown in FIG. This device is suitable for generating very short multi-pulses. Only one semiconductor switch T1 is required. An additional diode with a series connected resonant coil is not required in this variant. This is because it is not always necessary to return the energy during the multi-pulse operation. Due to the short and continuous occurrence of very short voltage pulses, a much lower pulse repetition frequency (eg 10 to 50 Hz) is possible than with single pulse operation (up to 400 Hz). Thus, the requirements for the underlying application can be kept small (as opposed to C. Maurisson, K. Paul, M. Kirsten, cited above; Experiments on pulsed current of dust collector under operating conditions ", 3. ICESP, Padua, 19
1987).

In the modification shown in FIG. 6, the magnetic switch is not directly connected to the dust collector 4, but is connected to the first terminals of the second resonance coil L3 and the second resonance capacitor C3. You. Closing of the magnetic switch L2 activates resonance oscillation. This resonance vibration is formed between the resonance coil L3, the resonance capacitor C3, and the parasitic capacitance of the dust collector 4 after the magnetic switch L2 has been opened again.

FIG. 7 shows a modified example of the multi-pulse operation by the potential separation. This pulse generating unit has a series circuit comprising a first semiconductor switch T1, a primary winding of a pulse transformer Tr, and a second semiconductor switch T2. Freewheeling diodes for demagnetizing the pulse transformer are labeled D1 and D2. The two semiconductor switches T1 and T2 are simultaneously turned on and off at each time. Obviously, other modifications are possible instead of this primary circuit.

The beginning of the winding of the secondary coil of the pulse transformer Tr is connected to the first terminal of the first resonance capacitor C2 and the first terminal of the magnetic switch L2 via a series circuit including the intermediate diode D3 and the resonance coil L1. Terminals. The second terminal of the magnetic switch L2 is connected to the first terminal of the second resonance coil L4 and the first terminal of the second resonance capacitor C3. The second terminal of the resonance coil L4 is connected only to the output terminal 3. The winding end of the secondary coil of the pulse transformer Tr is connected to the second terminal of the first resonance capacitor C2, the second terminal of the resonance capacitor C3, and the output terminal 3 '. FIG. 8 shows a typical transition of the voltage uDP (t) at the output terminals 3 and 3 ′ during the multi-pulse operation.
This is illustrated in FIG.

In the following, the method of operation of the entire pulse-feeding device, and in particular of the pulse-generating unit having a magnetic switch, will be described with reference to the device shown in FIG. 1 and the simulated current-voltage transitions shown in FIGS. It will be described with reference to FIG. The following terminology was used based on Table 1 below.

[0045]

[Table 1]

For the simulation, a parasitic capacitance of 100 nF was assumed for the dust collector. This corresponds approximately to the values that are usual for dust collectors in large furnaces. The value of the resonance capacitor C2 was selected to be 120 nF, and the value of the intermediate circuit capacitor C1 was selected to be 400 nF.
The resonance coils L1 and L2 have a first resonance phase of about 30 μm.
It was sized such that it ended after s (time T1 in FIG. 10) and the phase for energy recirculation ended after about 15 μs (time T4 in FIG. 10). For magnetic switches, commercially available soft magnetic core materials with the properties required for the basic application (for reference, see Literature, Richard Bol, "Soft Magnetic Materials" 4th Edition, Varkum Schmel Tse Geembehr) can be used. In this case, the magnetic switch has the first resonance phase closed under any operating condition, and the semiconductor switch is opened again before the magnetic switch is closed (time T2 = 4 to 6 μs in FIG. 10). It must be of such a size. If this is guaranteed, the semiconductor switch is protected against short circuits (voltage crossing) on the load side.

The pulse repetition frequency for single pulse operation was selected to be 400 Hz. This corresponds to a period of 2500 μs (time TPS in FIG. 9). Intermediate circuit voltage is 8
The simulation was performed at 0 kV and the low DC voltage was 20 kV. Choosing the size results in a voltage peak at the load of about 130 kV. Approximately 4μ to reach peak value
s (time TS1 in FIG. 10).

To explain the method of operation, it is first assumed that the semiconductor switch T1 is open. Capacitor C
The voltage at 1 is 80 kV. The capacitor C2 and the dust collector (4) are charged to a low DC voltage (20 kV).

The first oscillation is started by closing switch T1. As shown in FIG. 10, a half-sine resonance current iL1 (t) flows. The capacitor C2 is charged at resonance. At the end of the first oscillation phase (time interval T1), the voltage on capacitor C2 reaches a maximum. This maximum value depends on the ratio of the two capacitors C1 and C2 (double voltage principle). This ends the first vibration phase. As soon as the resonance current reaches the zero value again, the semiconductor switch opens.

During the first oscillating phase, as the voltage on capacitor C2 rises, simultaneously a small magnetizing current iL
2 (t) flows through the magnetic switch L2. The magnetic flux in the core of the magnetic switch L2 is slowly increased until the saturation limit is reached (time interval T2). Magnetic switch (L2)
The inductive inductance of the present invention, for the corresponding magnetic material, decreases almost abruptly to the value at saturation. This results in a pulsed current increase in the magnetic switch. As a result, the dust collector is charged very quickly at resonance (time interval T3).

As soon as the voltage at the dust collector reaches the value of the intermediate circuit voltage (approximately in the middle of the time interval T3), the diode D1 becomes conductive. The return of energy from the dust collector to the intermediate circuit capacitor C1 via the resonance coil D1 starts slowly. This third resonance phase ends after the current through diode D1 has again reached zero after time interval T4. If the condition T4> 2.5T3 is respected, the return, which already starts in the middle of the second resonance phase, has little effect on the maximum achievable voltage swing at the load. Furthermore, it is now directly recognized that by providing the resonant coil L3 correspondingly, the reflux time can be affected appropriately.

One complete cycle has thus proceeded. The semiconductor switch T1 can be turned on again. Semiconductor switch T1 for individual pulses or pulse trains
Is performed by a control circuit (not shown).

The method of operation of the device shown in FIGS. 2 to 5 corresponds to the circuit shown in FIG. 1, with the exception of the differences already mentioned above. In the device shown in FIG. 6, the first two resonance phases end correspondingly as in the device shown in FIG. Instead of an energy return circuit, in this variant another resonance circuit for generating very short multi-pulses is provided. Such a free-damped oscillation adjusted between the resonance coil L3, the resonance capacitor C3 and the parasitic capacitance of the dust collector 4 is activated by a magnetic switch. Turning on the magnetic switch again without control can be completely omitted in this case because the third resonance circuit has a corresponding size.

In the device shown in FIG. 7, the initialization of the pulse at the reduced voltage level is achieved by turning on both semiconductor switches T1 and T2 (here having IGBT switches instead of thyristors). Is performed. The capacitor C3 is charged at resonance via the pulse transformer and the intermediate diode D3. Subsequently, the third resonance phase is activated again at the load by closing the magnetic switch, corresponding to the device shown in FIG. The intermediate diode D3 is necessary because otherwise the transformer would saturate after energy transfer has taken place. By means of the two diodes D1 and D2, the primary side demagnetization of the transformer can be guaranteed.

[Brief description of the drawings]

FIG. 1 has pulse generation means without potential separation for single-pulse operation and quasi-multi-pulse operation, a magnetic switch, and an additional resonant coil for a configurable configurable energy return time, FIG. 1 is a diagram of a device for supplying a pulse power to an electrostatic precipitator having no power unit for low DC voltage.

FIG. 2 is a diagram of a pulsed power supply device having a resonance coil having no potential separation as in FIG. 1, but having different numbers of turns N1 and N2.

FIG. 3 is a diagram of a pulse power supply device having no potential separation as in FIG. 1 but having only one resonance coil.

FIG. 4 is a diagram of a pulsed power supply as in FIG. 3, without potential separation, but with an additional power supply unit for low DC voltages connected to the network.

FIG. 5 is a diagram of a pulsed power supply as in FIG. 3, without potential separation, but with an additional power supply unit for low DC voltages, for power supply from an intermediate circuit.

FIG. 6 is a diagram of a pulsed power supply without potential separation, with an additional resonant circuit for multi-pulse operation, and without a power supply unit for low DC voltages.

FIG. 7 is a diagram of a pulsed power supply having an additional resonant circuit for potential separation and multi-pulse operation, and here an additional power supply unit for low DC voltages.

8 (a) shows a typical change of voltage and a single pulse operation in a dust collector in the power supply device shown in FIGS. 1 to 5, and FIG. 8 (b) is shown in FIGS. 1 to 5; FIG. 8 (c) shows a typical transition of the voltage at the dust collector in the power supply apparatus shown in FIGS. 6 and 7, and FIG. And FIG.

FIG. 9 is a diagram showing the simulated current-voltage transitions over time in the power supply shown in FIGS. 1 to 5 for single-pulse operation and a pulse repetition frequency of 400 Hz.

FIG. 10 shows FIG. 1 during single pulse operation.
FIG. 6 is a diagram (partially detailed diagram) showing simulated current / voltage transitions over time in the power supply devices shown in FIGS.

[Explanation of symbols]

 1.1 First power supply unit 1.2 Second power supply unit 2, 2 'Output terminal of power supply device 3, 3' Output terminal of pulse generation unit 4 Electrostatic dust collector 5, 5 '... Output terminal of the second power supply unit AC ... AC voltage network C0 ... capacitor C1 ... intermediate circuit capacitor C2 ... first resonance capacitor C3 ... second resonance capacitor D1 ... diode D2 ... diode D3 ... diode L1 ... first 1 resonance coil L2 ... magnetic switch L3 ... second resonance coil L4 ... third resonance coil L13 ... resonance coil having two windings N1, N2 ... windings R1, R2 ... resistance Tr ... pulse transformer T1, T2 ... Semiconductor switch

Claims (8)

[Claims] 1. High pulse frequency, only 10 μs
A device for feeding a pulse to an electrostatic precipitator (4) that enables multi-pulse operation, single-pulse operation or quasi-multi-pulse operation for smaller pulse widths and higher pulse voltage amplitudes greater than 100 kV. A) The intermediate circuit voltage (uC1 (t)) is applied from the AC voltage network (AC) to the output terminal (2, 2 ') and the intermediate circuit capacitor (C1) connected in parallel to the output terminal (2, 2'). B) a pulse generating unit, and b1) the pulse generating unit is connected in parallel to the intermediate circuit capacitor (C1), and includes a first resonance coil (L).
1) including a series circuit including a semiconductor switch (T1) and a resonance capacitor (C2); and b2) including exactly one magnetic switch (L2), and a first terminal of the magnetic switch (L2). Is connected to a connection point between the semiconductor switch (T1) and the resonance capacitor (C2), and a second terminal of the magnetic switch (L2) is connected to the dust collector (4). B3) the pulse generating unit is connected to a first resistor (R1);
B4) includes a series circuit comprising a diode (D1) and a second resonance coil (L3), and capable of returning energy; b4) the output terminal (2) for the power supply unit; A first resistor (R1) connected between the output terminal (3) for the pulse generating unit and the magnetic switch (L2);
And a second resistor (R2) connected in parallel to the power supply device, and these resistors (R1, R2) generate an almost constant low DC voltage equal to or lower than the corona starting voltage during a pulse pause. 2. A resonance coil (L) having two windings (N1, N2) instead of the first resonance coil (L1).
13) is used, and the second winding (N2) is
Instead of the resonance coil (L3), and the turns ratio (N1 / N
2. Device according to claim 1, characterized in that the change in 2) can influence the time for the return of energy. 3. The second resonance coil (L3) is not provided, and the diode (1.2) is connected to the output terminal (3) for the pulse generation unit and the first resonance coil (L3). The power supply device according to claim 1, wherein the power supply device is connected between a connection point between the semiconductor switch (L1) and the semiconductor switch (T1). 4. The power supply unit (1.2), wherein the first first resistor (R1) is not provided and the low DC voltage is generated by a second power supply unit (1.2). ) Is the output end (5, 5 ′) of the dust collector (4).
And an input terminal is connected in parallel to the intermediate circuit capacitor (C1) or is applied from the AC voltage network (AC). The power supply device according to claim 1. 5. A device for generating multi-pulses of very short pal duration and for supplying pulses to an electrostatic precipitator (4), comprising: a) a voltage applied from an alternating voltage network (AC); A power supply unit (1.1) for applying an intermediate circuit voltage (uC1 (t)) to an output terminal (2, 2 ') and an intermediate circuit capacitor (C1) connected in parallel thereto; B1) the pulse generating unit is connected in parallel with the intermediate circuit capacitor (C1), and the semiconductor switch (T1)
), A first resonance coil (L1), and a series circuit consisting of a resonance capacitor (C2). B2) It includes exactly one magnetic switch (L2), and a first switch of the magnetic switch (L2). Is connected to a connection point between the first resonance coil (L1) and the resonance capacitor (C2), and a second terminal of the magnetic switch (L2) is connected to a second resonance capacitor (C3). The second terminal of the second resonance capacitor (C3) is connected to a first terminal and a first terminal of a third resonance coil (L4). Terminals (2 ', 3
'), And a second terminal of the third resonance coil (L4) is connected to the output terminal (3) of the pulse generation unit; b3) The pulse generation unit is further connected in parallel to the magnetic switch (L2) and the third resonance coil (L4), a second resistance resistor (R2), and an output terminal for the pulse generation unit (R2). 3) A power supply device comprising a first resistor (R1) for connecting the output terminal (2) to the output terminal (2) for the power supply unit. 6. A device for pulse-feeding an electrostatic precipitator (4), capable of generating multi-pulses of very short pulse duration and using a pulse transformer (Tr) for potential separation. A) applying an intermediate circuit voltage (uC1 (t)) to an output terminal (2, 2 ') and an intermediate circuit capacitor (C1) connected in parallel to the output terminals (2, 2'); A power supply unit (1.1); b) a low DC voltage applied from the AC voltage network (AC) or from the output end (2, 2 ') of the first power supply unit (1.1). A second power supply unit (1.2) to be applied, the output terminals (5, 5) being connected in parallel to the output terminals (3, 3 ') of the pulse generation unit
′), And c) the pulse generating unit having the pulse transformer (Tr), and c1) the pulse generating unit includes the first power supply unit (1). .1), a primary winding of a first semiconductor switch (T1), a primary winding of the pulse transformer (Tr), and a second semiconductor switch (T2).
) And a demagnetizing diode (D1,
D2) and the two semiconductor switches (T1, T2).
) Are turned on and off simultaneously each time, c2) the pulse generating unit comprises on the secondary side a series circuit consisting of a mediating diode (D3) and a first resonance coil (L1), and the mediating diode (D3) Is connected to the winding start end of the secondary winding of the pulse transformer (Tr), and the resonance coil (L1) is connected to the first terminal of the first resonance capacitor (C2) and the magnetic switch (L2). The second terminal of the magnetic switch (L2) is connected to the first terminal of the fourth resonance coil (L4) and the first terminal of the second resonance capacitor (C3). Connected, a second terminal of the fourth resonance coil (L4) forms a first output terminal (3) of the pulse generation unit, and a winding end of the secondary winding is connected to the resonance capacitor (C2). , C3)
Terminal and the second output terminal (3
C3) In the pulse generating unit, a resistor (R2) is connected to the output terminal (3) of the pulse generating unit and the first terminal.
And a connection point between the resonance coil (L1) and the magnetic switch (L2). 7. The pulse generating unit, wherein the semiconductor switches (T1, T2) are thyristors, GTOs, IGBTs.
Or selected from MCT.
The power supply device according to any one of claims 6 to 6. 8. The power supply unit according to claim 1, wherein at least one of the power supply units is designed as a switchable power supply unit. The power supply device according to claim 1.