DE919059C - Mechanical switching converter (contact converter) - Google Patents

Description

Mechanical switching converter (Kontaktumf orm. Er) Addition to patent 869 983 The main patent proposes that for mechanical switching converters with pre-magnetized switching chokes arranged in series with the switching contacts, an automatic adjustment of the pre-magnetization flow of the switching throttle should be established by producing this flow from at least one duration of the current level and a portion that is dependent on the voltage that prevails at the respective switching inductor during the current level. In an embodiment based on switching off, the constant portion of the bias magnetic flux of the switching choke, which is preferably equipped with stretching circuits, is generated by a pre-magnetization with direct current and the voltage-dependent portion is generated by a biasing circuit, which the voltage applied to the series connection of the switching choke winding and the switching contact is generated via a feeds ohmic resistance. This voltage-dependent premagnetization circuit contains a valve, preferably a dry-type rectifier. By using such a premagnetization of the switching choke it is achieved that the contacts of the switching current converter open practically without current or voltage at the end of the current-carrying times under all operating conditions that occur.

The invention consists in the use of such a composite Pre-magnetization for generating switch-on levels. Accordingly, there is the premagnetization of the switching reactor from one during the duration of the switch-on level constant proportion and from one of the voltage on the series connection of Contact and throttle-dependent proportion. This makes it possible that the contacts are practically de-energized and de-energized at the beginning of their current-carrying times conclude.

The invention is explained below with reference to a few embodiments shown in FIGS. 1 to 5 and 7 to 16 for a single-phase rectifier circuit and a diagram (FIG. 6) . In FIGS. 1 to 4 and 1: 2 to 15, a contact actuation device of any type can be added. For the examples according to the other figures, an electromagnetically operated contact is provided. For all examples, however, it applies that the pre-magnetization arrangement applies mutatis mutandis to single-phase and multi-phase switching converters in general, ie z. B. is applicable to those with motorized contacts. All figures have in common an AC voltage source i, e.g. B. the secondary winding of a single-phase rectifier transformer, a switching reactor 2 with a main winding 3, a contact 4 and a DC-side load 5. This is assumed in the example as an ohmic load.

In Fig. I, a circuit proposed in the main patent for the switch-off stage for generating the voltage-dependent bias component is first repeated. It is a bias circuit consisting of an auxiliary winding io of the switching inductor 2, an uncontrolled valve 12 (dry rectifier) and a setting resistor ii. This arrangement can be transferred to a switch-on choke 2 'with the main winding 3' in such a way that it is designed in the same way. ter bias circuit, consisting of an auxiliary winding 21, a valve 1: 2 'and a setting resistor ii' with reverse flow direction of the valve parallel to the series circuit consisting of the switching inductor winding 3 ' and the contact 4 is connected. Instead of the special auxiliary winding 2,1 part may just as in the Ausschaltvormagnetisierung instead of the auxiliary winding io of FIG. 2, the main winding 3 and 3 'of the shift reactors be involved in saving circuit in the respective bias circuit. Fig. 3 shows the union of the two similar pre-magnetization circuits for the on and off stage for the z. B. .. from patent 711311 known case that the switching reactors 2 and: 2 'have a common main winding 3. According to the same patent, decoupling windings 2: z and 2? - 'are also provided, which prevent the effect of the switch-off magnetization on the switch-on core or, conversely, the switch-on diagnostics on the switch-off core and for this purpose with the same Win-Jung number as the effective part of the main winding 3 are equipped and connected with opposite winding directions. In the arrangement according to FIG. 4, where the cores are also combined into a single one, which is effective both when switching on and when switching off, the rectifiers 1: 2 and 12 'are omitted, and a single resistor 27 is for both directions used.

As constant Vormagnetisierungsanteil may be in the circuits of Figures i and:. 2, a dc bias, as proposed in the main patent for the Ausschaltdrossel using an auxiliary winding 6 (with opposite magnetization direction as the main winding), in the same way for the Einschaltdrossel using an auxiliary winding 6 'can be provided, but with a relatively opposite direction, that is to say in the same direction as the associated main winding, and possibly a different strength than for the cut-off throttle. The same applies to the arrangement of FIG. 3 where the clarity -because the auxiliary coils 6 and 6 'are omitted. About the constant Vormagnetisierungsanteil for an arrangement according to FIG. 4, where again an opening provided for this purpose auxiliary winding is located 6, In special cases, additional measures may be necessary, e.g. with voltage regulation through mechanical partial austerity. If the contact closure is delayed compared to the zero passage of the alternating voltage, then under certain circumstances the switching choke can be under the influence of the positively directed alternating voltage before the contact closes up to be re-magnetized to saturation. the Einschaltstlife would then elapsed before the contact closure and reproducing for their up to prevent a current increase immediately after contact closure at first, no longer be available. in addition, when used has a single shift reactor to produce the switch-on and switch-off stage a premagnetization with direct current, which is used as a constant component of the switch-off premagnetization, for switching on just the opposite direction. These various difficulties are addressed e.g. B. mastered by the additional measures described below.

In addition to the full modulation of the switching converter, there is also a Voltage regulation through partial modulation is possible, the activation of the voltage-dependent portion or the constant portion or both Components of the switch-on bias delayed so far that the switch-on stage only starts immediately after the contact has closed or so shortly before that a sufficient part of the step to temporarily prevent the current surge remains after contact closure.

So that when using a single throttle, z. B. corresponding to FIG. 4, the constant premagnetization component not only when switching on but also when switching off has the required direction, a bias magnetic flux in alternating direction is advantageously used for this component. This can, for. B. with high demands, have a rectangular or trapezoidal curve shape. If necessary, however, it is also possible, for. B. in the case of lower demands (low power, low control range), the constant component to be formed by a sinusoidal current in the winding 6 . The rectangular or trapezoidal curves can be achieved in a manner known per se by current distortion by means of direct current-biased saturation chokes (transducers) connected in series. Instead, currents with a trapezoidal profile can also be generated as anode or transformer currents by rectifier circuits. It is also possible and may be necessary to select different sizes for the level of the constant premagnetization component when the contact is switched off and when it is switched on. This can be achieved in a simple manner by an additional premagnetization of the switching reactor core with direct current. When using saturable chokes to generate the trapezoidal current, the direct current required to premagnetize these chokes can simply be passed through an additional winding on the switching choke core.

The desired delay in the use of one or both premagnetization components can be achieved by a controllable valve, e.g. B. be brought about by a grid-controlled gas or vapor discharge vessel. A cesium vapor discharge vessel is particularly suitable for this because of its low arc voltage drop. The deployment delay can also be effected magnetically, e.g. B. by using a so-called valve throttle, d. H. the series connection of a direct current pre-magnetized saturation choke with a preferably uncontrolled valve. In both cases it is important that the application of the bias current is brought into the correct temporal relationship to the moment the contact is closed.

In the case of contact converters with motor-driven contacts, for example, the motor-driven switching bridge of the contact or a separate pre-contact can supply the grid of the controllable valve with a positive control pulse that causes the valve to ignite. In the case of switching converters with electromagnetically operated contacts, the ignition pulse for the controllable valve located in the premagnetization circuit can be made dependent on the control pulse for the contact closure. If a special control circuit is used for the electromagnetic actuation of the contacts in a manner already proposed otherwise, which contains a grid-controlled discharge vessel or a saturation reactor with variable pre-magnetization as control means and is galvanically, inductively or capacitively coupled to the main circuit of the switching converter, so the same delay device can even be used together for the contact closure can be used as for switching on the bias current. One after the aforementioned point of v-ervollständigte circuit, for example, Fig. 5. Thereafter, a constant during the Ausschaltstufe Vormagnetisierun.g by means of a bias winding 6 is formed on the core of the Schaltdro # Key. 2 The winding 6 is fed by the trapezoidal alternating current of a transducer 7, which is connected, for example, to the secondary winding i of the rectifier transformer. To set the correct phase position, the connection can be via phase rotation means, e.g. B. via a rotary transformer. The direct current required to premagnetize the transducer 7 can be taken from a direct current source 17, for example. A setting resistor 8 and a stabilizing choke g are located in the DC circuit of the transducer 7. The direct current flows at the same time through an auxiliary winding 6 ″ on the core of the switching throttle 2, whereby a direct current flowing through the trapezoidal flow through the winding 6 can be superimposed . A stretching circuit consisting of a capacitor 14 and a resistor 15 is connected to improve the step shape.

As in the arrangement according to FIG. 3, the voltage-dependent component of the switch-off bias is supplied by the series connection of the resistor ii with the valve 12, which is connected to a tap on the main winding 3 of the switching throttle 2 and, on the other hand, to the side of the contact 4 facing away from the switching throttle 2 connected. The closing and opening of the contact 4 takes place in a manner already proposed elsewhere by a shunt control circuit, which consists of the control coil 16 of a magnet system associated with the contact 4, not shown in the drawing, a direct current source 17, a controllable valve 18 and a setting resistor ig . In the main circuit of the switching power converter or a forward main current-carrying magnet coil 2o is in series with the contact 4 arranged, which is of the same magnet system as the control coil 16. and which, when the current-carrying contact 4 is closed, supports the action of the coil 16 in the sense of an increase in the contact pressure as the consumer current increases.

The constant portion of the switch-on bias is supplied by the bias winding 6 , which is also used for the switch-off, but the other, oppositely directed trapezoidal half-wave comes into effect. The circuit of the voltage-dependent portion of the switch-on bias is in turn parallel to the series circuit consisting of the switching inductor winding 3 and the contact 4. It is formed from a bias winding 21 accommodated on the core of the switching inductor 2, a controllable valve 24 and an adjustment resistor 23 and is connected, for example, to a tap a of the direct current source 17. The valve: 24 can be a grid-controlled gas or vapor discharge vessel. The voltage of the part of the voltage source 17 located in the premagnetization circuit is preferably chosen so that the burning voltage drop of the valve 24 is almost compensated, but the voltage source 17 cannot maintain the arc of the valve 24 without the additional effect of a further voltage component originating from the transformer i . With such a dimensioning, the valve 24 goes out immediately after the switch-on stage has elapsed and is only re-ignited by a new control pulse after the beginning of the following period. It is also possible to connect the anode of the valve 24 to the positive pole P of the voltage source 17 or to its negative pole N instead of the tap a. The latter can be particularly advantageous if a valve with only a low operating voltage is used as the valve 24, e.g. a cesium vapor discharge vessel. In this case, the effect of the drop in operating voltage at the valve can be compensated for on the level of the premagnetization component generated by this circuit by a corresponding adjustment of the number of turns of the auxiliary winding 6 ″ .

The operation of the circuit of FIG. 5 will now be explained with reference to Fig. 6. It shows the sinusoidal voltage e of the transformer winding i, the time profile of the current i in the control circuit of the winding 16 and the time profile of the current I flowing through the contact 4, which is essentially equal to the load current. The valves 18 and 24 may be released at the same time, which z. B. can be done by Entnahine the grid control pulses for both valves from a common, not shown control transformer. The release of the valves may also be delayed by a selectable angle α with respect to the zero crossing of the alternating voltage for the purpose of voltage regulation. Then, the control current i rises in the winding 16 as in shown in FIG. 6 as shown. At the point in time E , the flow through the magnet system (coil 16) required to close the contact 4 is reached. After the contact 4 is closed, the control current initially rises even further, until the end of the switch-on stage AtE- Then the control current i sounds at a steady state determined by the voltage of the DC source 17, the operating voltage of the valve 18 and the ohmic resistances of the control circuit Value. The further course of the star current i in the area of the switch-off time A is of no interest in the context of the present considerations.

The voltage-dependent bias current also starts when the vessel: 2.4 is ignited. According to FIG. 6, this point in time is to be regarded as the beginning of the switch-on stage At_P. The mentioned current magnetizes the switching choke 2 -tets just so that a voltage occurs on its main winding 3, even when the contact 4 is still open, which is always equal to the voltage between the transformer-side connection of the switching choke (point N) and the direct current side of the contact 4. The contact 4, if it closes at time E , does not have to switch on any voltage if the premagnetization is correctly set, and after the closure of the contact 4, no stroni flows until the end of the premagnetization, because the premagnetization circuits take over the entire magnetization flow of the switching inductor. Without the measures described, a voltage UE would have to be switched on at the delay angle α. By contrast, due to the above-mentioned composite switch-on bias, the voltage itE is kept wholly or at least for the most part at the switching inductor until the switch-on stage has elapsed. The switch-on stage AtE practically takes place solely under the influence of the premagnetization. The contact current I is practically zero during this time and only rises to the value determined by the voltage c and the resistance of the load circuit after the switch-on stage has elapsed.

In Fig. 7 to 16 modifications of the switching example according to FIG. 5 are shown. Different, unchanged repetitive parts are omitted for the sake of clarity, z. B. the solenoids 16 and 2o, the stretching circuit 13 to 15 and all parts of the circuit for the constant portion of the premagnetization with exception of the winding 6.

In Fig. 7 it is shown that the direct current source 17 can also be inserted at the part of the series connection of switching inductor 2 and contact 4 connected to the load on the direct current side, without changing the operating mode. With this position of the direct current source 17 , with multi-phase operation there is the possibility of getting by with a single direct current source. As can be seen further from this example, the order of arrangement of the contact 4 and the main winding 3, the switch inductor 2 with respect to the arrangement of FIG. 5 can be changed.

In FIG. 8 it is illustrated that, instead of two controllable valves 18 and 24 (FIG. 5), it is also possible to manage with a single, common, controllable valve 24. Thus, not through the DC power source 17, an undesirable current in from the bias winding 21 and the resistors 23 and ig existing, is generated in it, closed circuit, a valve 25 is inserted that locks the given by the voltage of the power source 17 flow direction . On the other hand, so that during the switch-off stage, when a voltage is generated in the bias winding 2 1 that is opposite to the voltage of the current source 17 and outweighs this, a current flow in the opposite direction does not occur in the same circuit, a valve --6 is also provided . The two valves 25 and 26 thus prevent an undesired additional premagnetization of the switching throttle 2.

In Figs. 7 and 8, the circuit of the Einschaltvormagnetisierung, as well as in the circuit of Fig. 5, instead be connected to the tap of a current source 17 and to the full operating voltage (Pool N) or to the positive pole P. In the former case, the valve 25 can optionally also be omitted.

In FIG. 9 it is shown that part of the main winding 3 of the switching inductor 2 can be used in an economy circuit instead of a separate bias winding 21 (FIG. 8) for the delayed onset of switch-on bias.

Fig. I o shows that the same simplification is also possible if the direct current source 17 is not on the consumer side of the switching throttle, but on the transformer side.

In FIG. Ii, an even further simplification of the circuit, which is advantageous in some cases, is created in that, instead of the two separate bias resistors ii and 23 (FIG. 10), only a single, common resistor: 27 is present.

The circuits of FIGS. 12 and 13 show, as the circuits can be simplified as shown in FIGS. Io and ii in such switching converters, in which the 16 (Fig. 5) and the resistance ig existing control circuit from the DC power source 17, the control coil for the actuation of the contacts is not necessary if this is done in another way, e.g. B. motor driven. The control of Einschaltvormagnetisierung can be carried out as a function of switching torque or the switching state of the contact. 4 The bias circuits then only consist of two branches or a single branch, the direction of the current being determined by the controllable valve 2, 4 when switched on and that when switched off by the valve 12. To enable the switch-on bias, the control circuit of the valve 24 can be routed via the moving part of the contact 4 or via a special pre-contact assigned to it.

14 and 15 are modifications of the circuit according to FIG. 13. They make it clear that it is fundamentally irrelevant for the invention with regard to the mode of operation, apart from a practically slight influence of the scatter, whether an economy circuit according to FIG. 13 or a separate auxiliary winding 21 (Fig. 14) with the same effect as the main winding 3 or an auxiliary winding 29 (Fig. 15) connected to the connecting line of the contact 4 with the throttle: 2 with the opposite effect as the main winding 3 is used.

In Fig. 16, which corresponds to the circuit according to Fig. 9 , is shown as an example of a purely magnetic control how the controllable valve 24 (Fig. 9) common to the premagnetization and the control circuit by a magnetically controllable arrangement with valve action, z. B. a so-called valve throttle can be replaced, which consists of an uncontrolled valve 30 and a direct current biased saturation choke 34 with an iron core 32, a main winding 31 and a bias winding 33 , which the latter is flowed through for the purpose of voltage regulation by a variable in its size direct current .

While the converter arrangements according to FIGS. 5 and 7 to 16 contain only a single switching throttle with which both the switch-off stage and the switch-on stage are generated, separate chokes can also be used here for these two functions and the circuits described can be modified accordingly.

Claims (2)

PATENT CLAIMS: i. Mechanical switching converter with pre-magnetized switching chokes in series with the contacts, characterized in that the pre-magnetization used to generate switch-on stages according to Patent 869 983 consists of a component that remains constant during the switch-on stage and a portion that depends on the voltage at the series connection of contact and switching choke. 2. Switching converter according to claim i, characterized by means (24, 34) for delaying the use of one or both premagnetization components, such that the switch-on stage only begins immediately after the contact closure or so shortly before that a sufficient proportion of the stage after the contact closure for temporary prevention of the current surge remains available. 3. Switching converter according to claim i, characterized by the alternating direction of the constant portion of the premagnetization (winding 6). 4. Switching converter according to claim 3, characterized by means (7) which have the effect that the time course of the constant portion of the bias current has a rectangular or trapezoidal shape. 5. Switching converter according to claim 4, characterized in that a DC-biased saturation choke arrangement (7) is used to generate the rectangular or trapezoidal shape of the bias current. 6. Switching power converter according to claim 5, characterized in that smoothing means, preferably a smoothing choke (9), optionally in connection with an adjustable resistor (8), are switched on in the biasing circuit of the direct-current biasing saturation choke arrangement (7). 7. Switching converter according to claim 4, characterized in that the anode or transformer current of a rectifier circuit is used as a rectangular or trapezoidal bias current. 8. Switching converter according to claim 3, characterized in that the time course of the constant portion of the bias current (winding 6) has a sinusoidal shape. G. Switching converter according to Claim 3, characterized in that the constant portion of the bias current (winding 6) is taken from the AC supply voltage of the switching converter via phase rotation means. ok Switching converter according to Claim i, characterized in that the level of the constant portion of the switch-on bias is different from the level of the constant portion of the switch-off bias. ii. Switching converter according to claim 3, characterized by an additional direct current bias (winding 6 ") of the switching reactor. 12. Switching converter according to claim 5 and io, characterized in that the bias current of the saturation choke arrangement (7) at the same time for additional bias (winding (5") of the switching reactor ( 13. Switching converter according to claim i, characterized by an auxiliary circuit containing a setting resistor (i 1, 27), which is arranged parallel to the series connection of a switching inductor winding through which the main current flows, and the associated contact for generating the voltage-dependent premagnetization component , characterized in that the bias circuit is current-permeable in both directions for the purpose of common use for switching on and switching off a valve (24 or 12 ') is arranged with the flow direction in the sense of the main flow magnetization. 16. Switching converter according to claim 15, characterized by the use of an uncontrolled valve (1.2 ") in the case of a limitation of the adjustment range of the contact closure to a control range at least approximating the full modulation. 17. Switching converter according to claim 13, characterized by two similar premagnetization circuits containing valves ( 2,4 or 12 "and 12) with different forward directions for switching on and off. 18. Switching converter according to claim 17, characterized by a common resistor (27) for limiting the bias current when switching on and off. ig. Switching converter according to Claim 13, characterized in that part of the main winding (3) of the switching inductor is in an economy circuit in the circuit of the voltage-dependent portion of the switch-on bias. 20. Switching converter according to claim 13, characterized in that an auxiliary winding (21) acting in the same direction with its main winding (3 ) is located in the circuit of the voltage-dependent component of the switch-on bias of the switching inductor. : 21. Switching converter according to Claim i, characterized in that the series connection of its main winding (3) and an auxiliary winding (29, Fig. 15) with opposing action lies in the circuit of the voltage-dependent component of the switch-on bias of the switching inductor. 22. Switching converter according to claim 2, characterized by a controllable valve (: 24), for. B. a grid-controlled gas or vapor discharge vessel, in particular a cesium vapor discharge vessel, to delay the onset of the switch-on bias. --3. Switching converter according to Claim 2, characterized by a direct current pre-magnetized saturation choke (34) in connection with a preferably uncontrolled valve (30) for delaying the onset of the switch-on pre-magnetization. 24. Switching converter according to claim 2, characterized by an additional voltage which compensates for the voltage drop across the delay means (24, 34). 25. Switching converter according to claim 2, characterized in that the effect of the voltage drop on the delay means (24, 34) is compensated by adapting the direct current bias (winding 6 ") of the switching inductor. 26. Switching converter according to claim i with electromagnetically controlled contacts, characterized by a control circuit, through which the main current does not flow, of the magnet system controlling the contacts, preferably with an auxiliary winding (16) of the latter.: 27. Switching converter according to claim: 26, characterized by such an excitation of the control circuit that the contacts during the time caused by the premagnetized switching choke Closing switch-on stage.: 28. Switching converter according to claim: 27, characterized by simultaneous closure of the control circuit and a circuit of the switch-on bias, preferably with the same control pulse. 29. Switching converter according to claim 28, characterized by a single controllable valve, e.g. B. a grid-controlled gas or vapor discharge vessel (2, 4) or a direct current biased saturation choke (34) in connection with a valve (30), for the common control of the switch-on bias and the contact closure (Fig. 8 to ii and 16). 30. Switching converter according to claim 29, characterized by an additional uncontrolled valve (25, 26) in at least one of the jointly controlled current branches, preferably in the current branch of the star winding of the contacts. 31. Switching converter according to claim i with motorized contact actuation, characterized in that the control of the switch-on bias is dependent on the switching moment or on the switching state of the contacts. 32. Switching converter according to claim 31, characterized in that the control circuit of a valve (22, 24) releasing the switch-on bias is routed via the moving part of the contacts or via a special pre-contact assigned to it.