SU960321A1 - Device for supplying electroplating baths with cyclic current - Google Patents

Description

The invention relates to a galvano technique, in particular, to devices for feeding electroplating baths with a reverse pulse, used, for example, in non-stationary electrolysis.

Closest to the invention, by technical nature, is a device for supplying electroplating baths with a periodic current, containing a stabilizing voltage converter, one of the inputs of which is connected to a clock pulse generator, a switch connected to a power reversing unit, and a unit for setting the forward flow time and reverse current 1.

A disadvantage of the known device is the absence of galvanic separation of the input from the output, which does not allow to operate with high voltages at the input of the device.

This circuit also does not allow changing and stabilizing the frequency and duty cycle of the output voltage. However, studies in the field of electrolytic electrolysis sites have shown that the deposition modes (frequency, duty cycle, power amplitude of its voltage) are uniquely determined by the physicochemical nature of the metal being deposited, i.e. for each type of metal being deposited, there is its own optimum mode. Consequently, in order to obtain the best quality coatings for the electrodeposition of various metals, the power sources for electroplating baths should be

10 to provide a change in the wide frequency range, the duty ratio, and the amplitude of the supply voltage with simultaneous stabilization by E during the deposition process.

15

In addition, in the known device, negative voltage feedback is not performed from the terminals of the electroplating bath, but from

20 inputs of a switching device using a voltage divider, which reduces the stabilization factor of the output voltage of the entire device.

25

The aim of the invention is to improve the quality of electroplating by separately adjusting and stabilizing the output voltage parameters: frequency, duty cycle, and

30 values of output voltage, duration t of direct and reverse current feeding the galvanic bath. The goal is achieved by the fact that a device for supplying electroplating baths with a periodic -current, containing a stabilizing voltage converter, one of the inputs of which is connected to a clock pulse generator, a switch connected to a reverse power supply unit, and a time and flow time setting unit currents, additionally equipped with a standard transformer, a frequency setting block, a block for setting and maintaining a pulse duty cycle, a feedback signal generating block, and a decadal time divider At the same time, a high-frequency stabilizing voltage converter is connected to the primary winding of the power transformer, and to the secondary power reversing unit, the output of the clock pulse generator is connected to a frequency reference unit connected in series, the duty cycle preservation and preservation unit and the switch, as well as a ten-day frequency divider connected in series with the time and flow unit of the forward and reverse current, the output of which is connected to the switch and to the signal generation unit connection, the inputs connected to the terminals of the galvanic bath, and the output to the stabilizing voltage converter. The signal conditioning / feedback unit can be implemented in the form of an output voltage storing circuit, to which inputs of the feedback commutator are connected, In addition, for the purpose of separate frequency control and borehole tuning and maintaining the wellness, 5, a pulse voltage driver, the first input of which is connected to a sawtooth driver and a reference voltage source, and the second with a frequency reference unit, the output of which is also connected to the sawtooth driver about tension. FIG. Figure 1 shows the f / n scheme of the device for feeding electroplating baths with a periodic current; Figures 2 and 3 are schematic diagrams of rectifiers and filters, respectively, for a three-phase and single-phase network; FIG. 4 shows pulse timing diagrams on; the output of the blocks of the proposed device; Fig. 5 shows four of the possible power supply modes of the electroplating bath; Fig. § - functional diagram of the block of tasks and preservation of the duty cycle. A device for supplying electroplating baths with a periodic current contains a stabilizing converter 1 voltage, consisting of a push-pull power converter 2 voltage and a circuit 3 controlling the power generator 2, POWER: transformer 4, power, reversing unit 5, clock generator b, set 7 task frequency, block 8 setting and saving well, block 9 setting the flow time of the forward and reverse current, switch Yu, block 11 of generating a feedback signal, consisting of the circuit 12, the output signal voltage and feedback switch 13, decade frequency divider 14, protection unit 15 g galvanic bath 16, resistor current sensors 17 and 18 and voltage 19, ammeters of direct 20 and reverse current 21, input 22 to 23.,. . ; ,,; :. . The stabilizing converter 1 serves to stabilize the output voltage of the device as a whole and to convert (invert) the voltage supplied to the input of the converter 1 into a high-frequency (over 20 kHz), high-voltage pulsed alternating voltage. The power transformer 4 electrically separates the input of the device from the output and converts the high voltage pulse voltage to low voltage. Siltsvoy reversing unit 5 reverses the output pulse voltage, the frequency, duty cycle and duration of the direct and reverse pulse of which are set and controlled in a wide range by blocks 7, 8 and 9 and a frequency divider. 14. The unit 8 for setting and maintaining the duty cycle, in addition, saves the specified duty cycle with a change in the frequency of the input pulses. The decade frequency divider 14 allows to increase the ranges of variation of the duration of the forward and reverse current from 10 to where n0, 1.2 ... k. The output voltage storage circuit 12 serves to convert the pulsing output voltage of the source 13 constant, store the latter and iodach it to the input of the control converter control circuit 3 1. It serves to turn off the output voltage storage circuit 12 from the terminals of galvanic bath 16 when the polarity of the electrodes of the electroplating bath 16 changes when the current is reversed. When the device operates without reverse, feedback switch 13 is turned on permanently.

The BJJOK protection 15 protects against overcurrent, b input and the output and against increasing the input and output voltage of the device as a whole.

The unit 8 for setting and maintaining the duty cycle consists of a sawtooth voltage generator 24, whose frequencies are equal to the frequency of the pulses of the frequency setting unit 7, the driver 25 and the pulse voltage, and the reference voltage source 26, which sets the various voltage levels corresponding to the required output voltage devices.

A device for supplying electroplating baths with a periodic current operates as follows.

A constant voltage is applied to the input terminals 22 and 23 of the device, which is either rectified-rectifier and filter-smoothed (Fig. 2 and 3) alternating voltage of a three-phase or single-phase network, or voltage from a source of constant voltage .

In the normal mode (with the absence of VII alarms), from the generator output of 6 clock pulses, clock pulses arrive at the inputs of the frequency setting unit 7, the ten-day frequency divider 14 and the control circuit 3. With the arrival of a clock pulse, control circuit 3 generates a pulse-width-modulated pulse signal of variable polarity U- (Fig. 4) with a pulse duration of Tk and is sent to the power converter 2 with a delay of 1–2 s, necessary for the termination of transients in the filters (Fig. 2 and 3), and control of the power converter 2i is performed. The power converter 2 converts the input DC voltage from terminals 22 and 23 into a high-frequency pulse alternating voltage, which is then applied to the primary power transformer 4. From the secondary winding of transformer 4, alternating voltage is supplied to power reversing unit 5. From the output of frequency setting unit 7, one of the possible variants of which is a voltage-to-frequency converter, is fed to the input of duty ratio setting 8 UT pulses (Fig. 4) of a technologically specified frequency setting.

From the output of block 8, the task and preservation of the duty ratio (Fig. 6) can be taken and 1 "L1 pulses of the same duty ratio at different frequencies

or the same frequency with different duty cycle.

The independence of the frequency spacing and the duty cycle occurs in the following way,

The triggering pulses Uj from the frequency setting unit 7, arriving at the first input of the pulse voltage maker 25, form the leading edge of the output pulses

Ug (Fig. 4) of the unit 8 for setting and storing a well. At the second input, the surge voltage driver 25 receives a sawtooth voltage from the saw voltage generator 24 and a constant voltage from the reference voltage source 26, at the instant of coincidence of the amplitudes of which the back front of the pulse Ug is generated. When it changes

the frequency of the triggering pulses of the SC changes and the moment of coincidence of the reference voltage of the source 26 and the pi of the voltage of the driver 24, in which the rear

front of the output pulse U. However, when etsm, the ratio of the period of the output pulse Ug to its duration, i.e. duty cycle, persists. From the output of the block 8

wounding ratio of pulses Ug

(FIG. 4) of a predetermined frequency and duty cycle arrive at one of the inputs of the switch 10. At the other input of the switch 10, pulses U are received from the block 9, specifying the flow time of the forward and reverse current, and the pulse duration and positive polarity correspond to the flow time of the direct current through electroplating bath 16, and

the duration of the pause between pulses and corresponds to the time of flow of the reverse current.

The output pulses of the forward and reverse current time setting unit 9 control the caldator 10, which distributes the impulses received from the setting unit 8 to maintain and maintain the duty ratio to one of its outputs V and Ufo.

(Fig. 4). The impulses from the switch postPoiot to the 5g power reversing unit where they connect the corresponding reversing power key

POWER reversing unit 5 to the terminals of the electroplating bath 16.

In the reverse mode, the polarity of the terminals (electrodes) of the electroplating bath .16 is changed, and in order for stabilization to take place during both the direct polarity and the reverse, the feedback signal generating unit 11 contains a feedback switch 13 and circuit 12 memorizing the output voltage. In the direct polarity mode, the voltage from the flow time 9 block of the forward and reverse current turns on the feedback switch 13 and the output voltage from the terminals of the electroplating bath 16 goes to the output voltage storage circuit -12, where it is converted from the pulsating into constant, stored and in the desired polarity is fed to the control circuit 3, which monitors the level of the output voltage, stabilizing it by a corresponding change in the filling factor of the pulses controlling the power switches and transducer 2,

In the reverse polarity mode, the feedback switch 13 disconnects the circuit 12: remembering the output voltage from the plating bath Ii6 and during this period the output voltage is applied by the voltage stored in this circuit.

Depending on the ratio of h & quotient, the duty cycle, the duration of the direct and reverse currents, the injected device can supply a galanic bath of various periodic currents. Four of these: those of greatest interest for practical purposes are shown in FIG. The duration of the pause between the pulses of the direct and reverse polarities t, - (fig. 5, d) is determined by the frequency properties of the power switches of block 5.

The choice of the shape of the supply current is most convenient to produce: an oscilloscope connected to the terminals of the electroplating bath 16.; . Thus, an improvement in the quality of the coating in the proposed device is achieved by separately adjusting and stabilizing the parameters of the electroplating bath voltage; the output voltage values are in the primary circuit, and in the secondary circuit - adjustment and stabilization of the frequency, duty cycle, and. the duration of the forward and reverse currents at. IeM independent regulation of frequency and duty ratio occurs due to the presence of the block of task and preservation of duty ratio. Independent adjustment of the parameters of the output voltage makes it possible with the same source from the same source to create the most favorable deposition values for the different deposited metals: which, in turn, leads to an increase in the quality of the coating. In addition, the high-frequency conversion carried out by the high-frequency stabilizing converter and the transformer transformer MF operating at a frequency above 20 kHz,

also allows you to increase the efficiency of the source by increasing the efficiency of the power transformer, and also allows you to reduce the weight and size of the source. For example, the use of regulated

high-frequency converter in the primary circuit of a power transformer, powered directly by rectified mains voltage and operating at a frequency of 25 kHz,

allows more than 3 times to reduce the size and weight of the proposed device; compared to the base.

The expected economic effect from the introduction of a single device

compile 4.23 thousand rubles

Claims (3)

1. A device for supplying a galvanic vine with a perirdic current, with stabilizing voltage converter, one of the inputs of which is connected to a generator of clock pulses, a crmmutagor connected to a power reversing unit, and a unit for setting the flow time of direct and reverse current, o ton. And so that, in order to ensure the quality of electroplating by separate control and stabilization of the parameters of the output voltage, it is additionally equipped with a power transformer, set the time mouths, the block setting and maintaining the duty ratio, the block forming the feedback signal and decadia 1 frequency divider, while the primary power source of the transducer is a stabilizing voltage converter, secondary secondary voltage of the reverse generator, clock generator output The pulses are connected to the serial link, the block, the frequency setting, the block of the set and the duty cycle and the frequency of the pulse, and also the decadal frequency, sequentially linked to the block of the set time. the flow and forward current flow, the output of which is connected to the switch and to the feedback signal generating unit, which are connected to the terminals of the electroplating bath, and the output to the stabilizing converter; wives, -. . . . . -. . . ... 2.UrtrOtvRa on p. 1, of tl ich and th and; This is due to the fact that the Forming | torn feedback signal block is made in the form of a circuit for storing an output voltage, to the inputs of which the outputs xc of the feedback switch are applied. 3. The device according to claim 1, that is, with the aim of Separate frequency control of the "squash" factor, the duty setting and maintaining the duty cycle is made in the form of a pulse voltage driver, the first input of which is connected to a reference voltage source and a sawtooth voltage driver, in the second - with a task block frequency, the output of which is also connected to the sawtooth voltage driver. Sources of information taken into account in the examination 1, USSR Author's Certificate 578369, cl., C 25 D 21/12, 1976. (cemt