DE1588746A1 - Device for controlling the voltage of a direct current consumer, e.g. of an electrostatic precipitator - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Erlangen *, ** ™ ^ϋ ·

PLA 67/1394

Device for controlling the voltage of a direct current consumer, e.g. an electrostatic precipitator

The invention relates to a device for controlling the Voltage of a direct current consumer, e.g. an electric liter with a thyristor controller in which the firing angle of the thyristors can be connected to its tax rate via a The DC control voltage can be changed and the DC control voltage which is passed through a transistor amplifier is used as the DC control voltage

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009883/0416

PLA 67/1394

DC capacitor voltage of an RC element is used to deose charging and discharge process is dependent on the current consumer operating values.

Bs is already a device for supplying voltage to Slektrofiltern known, in which the voltage taken from an alternating current network via a thyristor controller to a high-voltage transformer is led, which is in turn over The rectifier feeds the electrostatic precipitator.

Furthermore, it is known to use such a thyristor controller or another actuator, such as a magnetic amplifier, to be controlled depending on the pilter operating values, such as clamping ring and current.

In these electrostatic precipitators there is often a device provided, through which the voltage is reduced in the event of an overcurrent in the filter, e.g. from 30 kV to 25 kV, and then is slowly increased again up to 30 kV. To control this process one usually uses an RC element, which is discharged in the event of an overcurrent and then slowly recharged.

.Be is now often asked that the tension at the capacitor of the RC element and thus the voltage of the electrofilter only relatively slowly after a lowering process increase again boIIj e.g. from 25 to 30 kV within

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009883/0416

PLA

10 mins.

An RC timing element that exhibits such lateral behavior, is usually great with all-electronic components difficult to realize, since the connected your RC element after ^ Amplifier today is almost exclusively a transistor amplifier that always requires a certain input current. This but is only available if the. ··: part of the RC element is not chosen too large.

According to the invention, this difficulty is largely reduced by the fact that, in order to increase the R component a of the RC Glieäes the transistor amplifier is designed in two stages, the first stage essentially only to form a high-resistance Input resistance is used and only the second stage feeds the tax rate.

Experiments have shown that an RC element can be created by means of this solution mentioned above, which with a capacitor capacitance from 2000 µP a resistance component of 10 MΩ and allows more, whereas with the previously known RC elements with downstream transistor amplifier the limit for the resistance is lower by a power of ten. With others Words "through the two-stage transistor amplifier receives" time constants "which are higher by a whole power of ten al «those achievable so far. This has the advantage that one not going back to electro-mechanical solutions, such as time

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009883/0416

BATH ORIGINAL

reiäisVrückzugeh must * but άέϊί construction of the sbhaltürig from kbiitäktlaseh Elemeiiten can be adhered to *

Ärihäiid der Zeiöhüühg let the Erfiridüiig be explained in more detail:

Figs 1 shows ÖöhfeiriätisöH äie StäüBfÜhg öiheä

figi ^ d§ii Äliitjäü das ÖÖ-Öliecteä Üttd ä ^ ö ii-ahslötbfTör

lie äüö Figi 1 fereichtliöHi isi äri feiil

V üiid 5Ö.Hz practices · fine »from Ähtiparallel gfe-Ihyriöi tor often böäteHfeüden! Dh ^ riEitorsteller 2 öiri HböhSpärihuftgstrto & ibrinätöi ' 3 disconnected 30 kV. i) The voltage supplied to your filter is controlled by the thyristor controller 2 in the primary winding of the high-level transformer 3 # depending on the filter operating values. In the exemplary embodiment shown, the primary current and primary voltage of the high-voltage transformer 3 are used as the filter operating values.

The Primäfspannuiig des Hööhspannungstfansförmatbrs 3 is for this purpose with a chip dealer 7 removed the tax rate 6 of the thyristor controller 2 is supplied. With savings, »UsaiiHMienbruch as a result of Eürzschlüaöen blocks one

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ü 09 BÖ 3 / Ü4 1 6 "BAD 0R18SNAL

PLA 67/1394

Voltage release unit 24 via the tax rate 6 the Thyristor controller 2.

As already mentioned, the primary current is also detected by a current transformer 8 and fed to a current monitoring element. This current monitoring element consists - very schematically - of a flip-flop 9a »which responds whenever the rated current is exceeded and flips back again when the rated current is undershot, and a time flip 9b, which only occurs in the event of an overcurrent, i.e. for a current that is 10 $> above the rated current , appeals. The common output signal of these two stages is used in a device TO to generate the DC control voltage for the control set 6 of the thyristor controller 2. The device 10 consists of a RG-GIied with capacitor 14 (for example, L ⁵ OOO uF) and an adjustable resistor 15 (eg, 15-M) ', -welcher to a battery 16 24 V is connected by ZB. The collector emitter path of a transistor 12, the base of which is connected to the output of the current monitoring element 9, lies parallel to the capacitor via a likewise controllable resistor. The capacitor voltage that can be picked up at terminal 23 is fed via a two-stage transistor amplifier 11 to input terminal 22 ′ of the control unit. By changing this DC control voltage from +10 to -10 V, the firing angle of the thyristors in the thyristor controller 2 can be changed from 0 to 180 °. As already mentioned, the transistor amplifier 11 is constructed in two parts, namely its input stage 11 has one

'. ■ '.. - 5 - Ch / An'

009883/0416. ·. bad or, g _IN a _L

PLA 67 / i39f5887A6

very high input resistance, while the second stage 11b,,. feeds the tax rate 6. The importance of the high-ohm Singang3 resistor is explained below.

Assume, for example, that the nominal filter voltage is 30 kV and that the capacitor 14 has just been charged to a voltage that actually corresponds to this voltage. in the filter. If, for whatever reason, the current in the primary circuit exceeds the rated current, it speaks the flip-flop 9a on; their output signal makes the tranaistor 12 permeable. As a result, the capacitor discharges, depending on the setting of the resistor 13, until through the reduction in the capacitor voltage and thus the filter voltage falls below the nominal current again, so that the flip-flop 9a tilts back again and the transistor 12 blocks again. The capacitor 14 is then removed from the battery 16 again charged via resistor 15 until the original value is reached again. If it comes to exceeding again of the Neural Stream, this process is repeated anew. This arrangement works in the area of the "enristrome" in the manner of a two-position controller.

The dimensioning of the capacitor 14 and the resistor 15 This is not very critical, since it is usually about Voltage ^ drops of a few 100 V will act in can be undone in a very short time. "

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009883/04 16. BATH ORIGINAL

In contrast, the arrangement behaves differently in the case of fine Überetroraesi If, for example, an overcurrent occurs, the Zeitkijjpör speaks 9b and opens the Trahsis- ' Tor iSi Öie Sfianüühg becomes hiördur'öh every time a little bit more Öe'trägf nsE; Ute 25 ^? diverted. Beätfeht helps Üie ^ bräirüiigj dal dar Wiedfcrähstieg dfcSr Spüfiühf- ailf den SnÜWfert iÖ MiriUte'n däüferii bbll »^ o füh-ft difeb riörrnalerWeiöe sü

iikeitgHi da feiü HÖ-G'iiigd with such a fine Sbitver-H very ökftfer rfeäÜSiferbar i * atj This is based solely on the fact that the size of the resistor 15 is not arbitrary pWMkit terdeh kahh 1 jja always fine about a certain flow the frähsistör ¥ er'ätärke'r H ^ flows in!.! so axiirialfall kuhft the ■ fidfetötahä'üit'r eb herds made large "dai3 just high diöser" liebkötröin ¹ 'of RG-ÖÜeaeä can be met. One of enlargement of the C ~ Äht§iieS there are ebehfalis limits ^ on the one hand aüä t> RölBlicheh Grühdöh and on the other hand because of the growth dö-r. Virlüstei

In order to remedy this deficiency, according to the invention, the pre-gas amplifier 11 is designed in two stages and the first stage is provided with such a high input resistance that the leakage current I flowing into the transistor amplifier 11 becomes negligibly small, so that the R-Aiiteil 15 correspondingly of the RG-ßliedes can be chosen accordingly large *. %

More details about the structure of the transistor amplifier and the assembly 10 is shown in FIG. 2.

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BATH

PLA §7 / 1594 1588740

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ORIGlMAL BATHROOM

The device described above is particularly suitable for electrostatic precipitators, which normally have an approximately constant , • Hennatrom work and for filters with a constant overlap point.

As can be seen without further ado, the type of production described is The control voltage for the thyristor plate naturally does not affect its use in sieve filter systems limited, although it can be used there with particular advantage, but it can be applied there in all cases in which a very slow increase in voltage is desired, e.g. when demagnetizing ships or possibly also in electrophoretic systems the case L3t.

2 claims

-9- ChAn

/. 009803/04116 ^l "^{; l} BAD ORIGINAL

Claims (2)

PLA 67/1394 I588746 _v Godparents sayings. ,. ■ 1 / Device for controlling the voltage of a (battery-powered current consumer, e.g. an electrostatic precipitator with a thyristor divider, in which the firing angle of the thyristors can be changed by a control equilibrium that can be injected into its control set and in which the DC capacitor voltage fed via a transistor amplifier is used as the DC control voltage RC element is used, the charging and discharging process is dependent on the current operating consumption values, characterized in that the transistor amplifier (11) is designed in two stages to increase the R component of the RC element (14,15), the first stage (11a) essentially only serves to create a high-ohmic input resistance, and only the second stage (Hb) feeds the control set (6) of the thyristor controller (2). ',, 2. Device according to claim 1, characterized in that the transistor amplifier (11) consists of a translator (17) in the emitter circuit »in the emitter circuit of which there is an emitter resistor (18) and the base emitter path of a further transistor (19), and that the ah one in the emitter circuit of the second transistor (19) on one; Voltage divider (20, 21) detachable voltage is used as control DC voltage for the control set (6). \ .- ~. ... -, - * - - = - ^: - 10 - Ch / A » ir ,, ¹ : · ■■■:; ■) '■ "' _: -, 009883/0 ^ 16 BAD