DE3545471A1 - Voltage conversion system - Google Patents

Abstract

The invention relates to a voltage conversion system for electrical filters. This system consists of a high-voltage transformer 1 to whose primary side a thyristor controller 4 is connected and to whose secondary side a diode rectifier 5 is connected. The diode rectifier 5 is connected to the corona electrode 6 of the electrical filter 7. The single-phase high-voltage transformer 1, which has a high stray inductance, has two windings 2, 3 which are arranged concentrically one above the other, as well as an auxiliary winding 9 on a free iron return path limb. The auxiliary winding 9 is connected via a voltage converter 10 to an electronic controller 12 which acts on the thyristor controller 4. This voltage conversion system is considerably lighter than those which are known and, furthermore, the auxiliary winding 9 detects a short-circuit in the electrical filter 7, after which the electronic controller 12 influences the thyristor controller 4. <IMAGE>

Description

V ^. 'C ;; » £ i PRiETTSCH Gotihcrc'str. 81

D-3000 Munich 21

16,109

December 20, 1985

ELIN UNION

Public company for electrical industry

Penzinger Strasse

A-1141 Vienna

Austria

' Voltage conversion system '

-Z-

The invention relates to a voltage conversion system, preferably for electrostatic precipitators, consisting of a Thyristor controller, which is followed by a high-voltage transformer and a diode rectifier follows, whose output voltage is applied to the spray electrode of the electrostatic precipitator and that a voltage converter is connected to an electronic control that influences the thyristor controller.

For now, the functionality of the electrostatic precipitator will be briefly discussed explains which ones are mainly used where the mechanical centrifugal separators are the required separation efficiency can no longer be achieved. With these filters, dust is separated by charging the air to be cleaned into a strong one electrical direct voltage field approx. 20 to 60 kV. This is generated by the fact that the air passes through deletes parallel alleys, which are formed by plates, so-called precipitation electrodes. In In the middle of the alleys, wires connected as negative poles are arranged, which ionize the polluted air. As a result, the airborne dust is negatively charged and migrates to the earthed ones Precipitation electrodes, to which it adheres and by shaking with the plate knocking device in the the catching device below falls. Because the distance between the spray electrodes and the collecting electrodes must be very low, there may be a short circuit between the two Electrodes come.

In the known controlled voltage conversion systems for electrostatic precipitators, a thyristor controller is used in series a current limiting choke arranged on the primary side of the high voltage transformer. Short circuit occurs

on the secondary side of this transformer, which is created by an arc in the electrostatic precipitator, the short-circuit current occurring on the primary side results in an increase in the voltage drop at the throttle. Since a voltage converter is connected to the primary side of the high-voltage transformer its output voltage is lower than that of a Control for the thyristor controller is supplied. This voltage drop is therefore used electronically Control as a criterion for an arc.

This voltage conversion system is due to the current limiting reactor quite voluminous. It is therefore unusable in electrostatic precipitator systems with little space.

The object of the invention is therefore to create a voltage conversion system that is smaller and simpler is in the making.

The object is achieved by the invention, which is characterized in that the high-voltage transformer has a very high leakage inductance and a multi-legged core, with the upper and the low voltage winding concentrically at least eini core legs are arranged and that an unwound leg or a yoke with a Auxiliary winding is provided, which is connected to the primary winding of the voltage converter.

It is thus possible for the first time to produce a smaller and lighter, in particular half as heavy as the known, Build voltage conversion system. In addition, the losses are about 10 to 20 percent lower.

According to one embodiment, the high-voltage trans-

formator with the auxiliary winding and the diode rectifier arranged in a common oil-filled housing. This means that the same cooling medium can be used for the transformer and rectifier and In addition, material is saved for the second housing, as well as for bushings and connecting lines .

With reference to the drawings, wherein Fig. 1 is the circuit diagram of Voltage conversion system according to the invention and FIGS. 2a to 2d possible design variants of the high-voltage transformer show, the invention will now be explained in more detail.

In Fig. 1, the high-voltage transformer 1 with the primary 2 and the secondary winding ? to see. The primary winding 2 is connected to a single-phase alternating voltage via a thyristor controller, and the secondary winding 3 is connected to a diode rectifier 5. This is connected on the DC side to the spray electrode 6 of the electrostatic filter 7. The collecting electrode 8 and the positive pole of the rectifier f are set to zero potential.

The high-voltage transformer 1 also has a free iron yoke leg which is provided with an auxiliary winding 9 as shown in FIG. 2a. The two windings 2 ,? of the high-voltage transformer 1 are designed so that a very large leakage inductance occurs. This saves a primary-side current limiting reactor. A short circuit on the secondary side of the high-voltage transformer 1 is detected by the auxiliary winding 9.

If there is no short circuit, a voltage is induced in the auxiliary winding 9 by the magnetic flux occurring in the iron yoke leg. If a short circuit now occurs on the secondary side, the major part of the magnetic flux is displaced onto the stray paths between primary 2 and secondary winding 3, causing a drop in voltage on auxiliary winding 9, which is used to register the short circuit. The two windings 2, 3 are arranged concentrically, with the secondary winding 3 on the outside.

The auxiliary winding 9 is on a voltage converter 10 connected, the secondary winding 11 of which is connected to an electronic controller 12. This is a so-called automatic filter which controls the thyristor controller 4.

The high voltage transformer 1 with the auxiliary winding as well as the rectifier 5 are in a common Housing 1? Which is filled with oil is housed.

In Fig. 2a, the high-voltage transformer 1 is shown with two legs 14, with one leg 14 the two concentrically arranged windings 2, 3 are applied. The auxiliary winding is on the other leg 14 9 arranged.

Fig. 2b shows a jacket transformer with three Legs 14, in which the two outer ones have a smaller cross-section than the middle and on the the two windings 2,3 sit. One of the two outer yoke legs 14 has the auxiliary winding 9 on.

In Fig. 2c, the auxiliary winding 9 is arranged on the yoke of a two-limb transformer. The two legs 14 are each wound with half the high-voltage 3 and low-voltage windings 2. The two windings 2, 3 on each leg 14 are also arranged concentrically, the secondary winding 3 being on the outside.

In FIG. 2d, a four-leg transformer is shown, the iron core of which has two return legs 15 having. A return leg 15 is connected to the auxiliary winding 9 provided. Half of the upper 3 and half of the low voltage winding are on each of the two middle legs 14 2 applied.

Claims (1)

Claims Voltage conversion system, preferably for electrostatic precipitators, consisting of a thyristor interference point followed by a high voltage transformer and followed by a diode rectifier, the output voltage of which is applied to the spray electrode of the electrostatic precipitator and that a voltage converter is connected to an electronic control which influences the thyristor controller, characterized that the high-voltage transformer (1) has a very high leakage inductance and a multi-legged core, the upper (,?) and the low-voltage winding (2) are arranged concentrically βμί at least one core leg and that an unwound leg (14) or a yoke with an auxiliary winding (9) is provided which is connected to the primary winding of the voltage converter (10), Voltage conversion system according to Claim 1, characterized in that the high-voltage transformer (l) with the auxiliary winding (9) and the diode rectifier (5) in a common oil-filled housing (l?) are arranged.