DE1016822B - Control arrangement for high-frequency generators to keep the high-frequency voltage of a secondary treatment circuit constant, regardless of the load - Google Patents

Description

Industrial high-frequency generators for capacitive treatment purposes are often designed with two circuits, especially when the generator and treatment device are set up spatially separated need to be or if the capacity of the treatment electrodes is so large that a large part of the reactive current of the entire generator arrangement over the treatment capacitor flows. For reasons of stability, i. H. to avoid dragging symptoms or the like, is a very loose, if possible subcritical coupling between generator and treatment circuit necessary. As a result, the high frequency voltage on the treatment electrodes is dated Dependent on the tuning status of the secondary circuit. In most cases of practice, i. H. both at the continuous as well as discontinuous treatment method, changes either as a result uneven loading or changes in the dielectric properties of the goods, the coordination of the secondary circuit continuously or spontaneously. For this reason, in the case of two-circuit systems, the In most cases, ongoing readjustment of the secondary circuit is required to maintain the power supply to keep the good at the desired height. Manual retuning requires an additional one Operator and is, apart from the relatively high inertia and inaccuracy of the adjustment, uneconomical.

Methods for automatic tuning to the resonance peak are already known and carried out been. Here, the phase relationship is, for example, between the primary voltage and the current of the secondary circuit is used as a measure of the detuned state. However, this is so far disadvantageous as the resonance voltage depends on the damping of the working circuit, d. h., they falls with increasing load. On the other hand, the phase comparison is then not particularly technical easy to implement if the generator and secondary circuit are set up spatially far apart from each other will. In such a case, the high-frequency measured variable would have to be over correspondingly long lines are transmitted in the correct phase and independent of frequency.

According to the invention, these disadvantages are due to a simple and reliable construction Arrangement for the load-independent keeping of the high-frequency voltage of a secondary load circuit constant to a predetermined setpoint is eliminated in that a differentiating device known per se and a voltage-dependent control element is provided, which in the event of any deviation the adjusting element for the control capacitor from the operating point specified on the resonance curve

Rule arrangement

for high frequency generators for

load-independent keeping the

High frequency voltage of a secondary

Treatment circle

Applicant:

Siemens-Schuckertwerke

Aktiengesellschaft,

Berlin and Erlangen,

Erlangen, Werner-von-Siemens-Str. 50

Dipl.-Ing. Karlheinz Schmitter, Erlangen,

and Dipl.-Ing. Günter Meiners, Nuremberg,

have been named as inventors

via switching means, e.g. B. a stepping mechanism, a rotary selector and the like., In such a way that the Direction of movement is opposite to that direction of movement with which the adjusting member is the previous setting of the setpoint has moved, and that the differentiating device at wrong direction of movement of the adjusting member by an impulse reversal of the direction of movement of the adjusting element and thus sets the specified setpoint again. The one used Differentiating device preferably consists essentially of an i? C element in connection with a tube circuit that a polarized relay in the event of a positive or negative voltage change brings each of its rest position into one or the other working position. The one that is changing at the same time Voltage can be monitored by using a polarized relay using a reference voltage determines the positive or negative deviation from the target value. Instead, you can also Switching means are provided that control the ignition voltage of interrupters (grid-controlled gastriodes, Use suitable switching means to compare glow lamps or the like) with the voltage at the operating point.

The subject matter of the invention is explained in more detail with reference to the drawing:

In Fig. 1, the resonance curve 1 is shown, ie the high-frequency voltage U _HP as a function of the circular capacitance C ^.

709 699/154

The case of resonance is denoted by 2, while the desired voltage value 3 of the flank A and the voltage value 4 of the flank B were defined as operating points in accordance with the detuning of the secondary circuit. As can be seen from FIG. 1, the setting of each voltage value, with the exception of the resonance case, is ambiguous, that is to say that the voltage at point 3 increases with increasing capacitance, while at point 4 it increases with decreasing capacity

the voltage for the stepping mechanism 6 is interrupted by a switching pulse from the differentiating device 9 or from the control element 5, so the initial state is restored. The stepping mechanism 6 shown schematically in FIG. 2 corresponds in structure to that shown in more detail in FIG. 3. The correctness of the adjustment direction is monitored by means of a differentiating device 9, which in turn controls a polarized relay F,

Capacity increases. For this reason, you can either use the relay L or the

If there is a deviation from the nominal value, do not specify a generally applicable direction of movement for the adjustment element. The direction of movement therefore not only depends on whether the setpoint is exceeded or not reached,

Relay M interrupts the power supply to the stepping mechanism in a pulsed manner, thereby moving the stepping mechanism by one step. The relay F only has an influence on the stepping mechanism

but also on which flank the reso- 15 15 ie there is another turning impulse when the nanzkurve (A or B) is being worked. Direction of movement is wrong. Instead of the polar relay F shown in FIG 12 connected. The excess voltage change in each case one or the other monitoring of the switching tube on the treatment electrodes 13 ignites and the corresponding high-frequency voltage in the lying high-frequency voltage is carried out via relay L and M located in the anode circuit actuated conductors 14, the directional voltage of which is set with a setpoint.

is compared. This setpoint is measured on a span

voltage divider SP set. If the direction deviates, 25 Fig. 3 is shown. The arrangement is designed in such a way that

voltage from its setpoint at the operating point (see that after switching off the high frequency, a self-

Fig. 1) occurs due to the voltage-dependent active return of the adjusting element to a certain

Control element 5 takes place via the stepping mechanism 6, the misaligned output value. This is from the following

control element 7 in a fixed by the step-by-step mechanism appropriate reasons: As is known, influences the

The direction set in motion and actuates the value of the critical coupling in 30 damping, i. H.,

its size variable capacitor 8 because it is the critical coupling for a given load

responds to the polarized relay C in the control member 5, set. In this case, with increasing development

that the stepping mechanism 6 either over the load the coupling more and more overcritical,

Relay C _max or D _min switches on. According to the and there arise the well-known pulling phenomena, the

Direction of movement and the respective flank 35 after switching on the high frequency again

(A or B of Fig. 1) of the resonance curve, the high frequency voltage will increase or decrease. The resulting voltage curve is electrically differentiated with the aid of the differentiating device 9. Was

unchanged setting of the capacitor 8 and smaller damping, a skipping of the operating point to the other edge of the resonance curve may result. Through the automatic return

previously the target value of the operating point fell below, 40 run into the starting position and then with the correct direction of rotation of the adjustment reconnection through the organ 7, which takes place again and again, the high-frequency voltage and thus a
their proportional directional voltage during the

If the vote comes in from the same direction, this skipping is avoided, since the secondary circuit must always be positive on the same edge after the time. If the derivative 45 is drawn. However, this mode of operation becomes negative, ie the direction of adjustment is wrong, then the relay E switches. When switching off the

High-frequency voltage by actuating the switch HF-Ein , the relay E drops out. The contact e _x closes and the relay H in the stepping mechanism 6, sets the contactor W in action and thus moves the adjusting element 7 via the now closed contact w to the starting position of the adjusting capacitor 8. It is also possible to work without a stepping mechanism, namely such that the direction of movement

then himself via contact g ₃ . As a result, the contacts g _{2 are} closed and ^ ₁ opened in relation to one of the two flanks of the resonance. By curve, if there is a deviation from the setpoint, the latter is always correct, the auxiliary relay K receives voltage, and that is. The differentiating device only enters relay H is blocked. The relay K keeps itself appearance, if not on the selected edge via the contacts k ₂ and h ₂ . The relay G is determined to be worked. On this side, the other motion is 60 deviations from the desired value, the adjustment finishing of the adjusting member 7. If either nearest always wrong then at Abdie a and the relay H is, however, then each time m of said differentiating means 9 of the contact, or vice versa, the differentiating means. The latter and the contact d _min actuated by the control member 5, so order is particularly advantageous when the power supply to the relay G is interrupted and the adjusting member 7 is stopped mainly on a certain edge. The relay K maintains a resonance curve and is only operated as a result of spon-wide via the contacts k ₂ and Ji ₂ , until the step change in the attenuation and the dielectric switching mechanism 6 receives voltage again. Now the constant receives the other edge is reached. The relay H via the contacts k _v g _t voltage and keeps the high-frequency voltage constant can itself via the contact h _v The contact h ₂ will also take place in such a way that the adjusting element opens an adjustment; so that the auxiliary relay K drops out. Is now operated 70 capacitor in the primary circuit and thus through

position increase, d. i.e. the derivation of the directional span

a pulse is triggered by the differentiating device 9, which influences the stepping mechanism 6 in such a way that that the adjusting member 7 reverses its direction of movement.

The mode of operation of the stepping mechanism 6 is as follows:

When it is switched on for the first time, the relay G receives voltage via the contacts d _min , m, k _s and h _s , holds

Changing the frequency of the generator shifts the resonance curve accordingly. At the Execution and working methods do not change anything.

Claims (5)

Patent claims: 1. Control arrangement for high frequency generators to keep the high-frequency voltage of a secondary treatment circuit constant, regardless of the load, at a specified target value Use of a regulating capacitor lying parallel to the treatment capacitor, which is connected to Adjusted with the help of an adjusting device depending on the difference between two comparable voltages is, characterized in that a per se known differentiating device (9) and a voltage-dependent control member (5) is provided, which in the event of any deviation from on the Resonance curve given operating point the adjusting element (7) for the control capacitor (8) via switching means (6), e.g. B. a stepping mechanism, a rotary selector od. Like. In such a way in motion assumes that the direction of movement is opposite to the direction of movement with which the Adjusting member has moved in the previous setting of the setpoint, and that the Differentiating device in the event of an incorrect direction of movement of the adjusting element by an impulse causes a reversal of the direction of movement of the adjusting element and thus the predetermined Adjusts the setpoint again. 2. Arrangement according to claim 1, characterized in that the differentiating device (9) consists essentially of an i? C element in connection with a tube circuit, which a polarized relay (F) in each case from its rest position in the event of a positive or negative voltage change brings one or the other work situation. 3. Arrangement according to claim 1 and 2, characterized in that two switching tubes (grid-controlled gas discharge tubes) are provided in place of the polarized relay (F). 4. Arrangement according to claim 1 to 3, characterized in that a polarized relay (C) with A comparison voltage determines the positive or negative deviation from the nominal value. 5. Arrangement according to claim 1 to 3, characterized by switching means which control the ignition voltage of interrupters (19, 20) with the voltage at the operating point via resistance elements Compare (17, 18). Considered publications:
German patent specification No. 638 205. 1 sheet of drawings © 709 699/154 9.57