SU908560A1 - Power supply for electrophysical machining methods - Google Patents

Description

(54) POWER SOURCE FOR ELECTROPHYSICAL PROCESSING METHODS

one

The invention relates to electrophysical methods for the treatment of metals and relates to sources of pulsed voltage for this treatment.

A power supply is known that is made according to a bridge circuit with counter-parallel diodes, which contains a DC source connected via an input choke and a load connected to one of the diagonals of the bridge with a coupling capacitor and protective inductance. Another bridge diagonal is formed by a LC-chain 1.

A disadvantage of this device, which is a current, is the impossibility of obtaining amplitude-stable voltage pulses with variations in the resistance of the interelectrode gap.

The purpose of the invention is to expand the functionality of the source by obtaining voltage amplitude-stable voltage pulses with a steep leading edge, with a wide range of control over their duration, frequency and duty cycle.

To achieve this goal, a source consisting of a direct current source connected to the source through the input choke of a thyristor bridge with counter-parallel diodes and an LC circuit in the KOMMJT of the diagonal, the other diagonal of which is closed on the separation capacitor and protective inductance, is inserted into the thyristor bridge -sequential thyristor, the anodes of which are connected to the LC-circuit of the thyristor bridge, and the connection point of the cathodes is connected to the positive terminal of the interelectrode gap, to the negative todu which is now negative DC source

IS current.

The drawing is a two-cell pulse source circuit diagram. Cells A and B are identical.

The source of pulsed voltage consists

Claims (1)

20 from a DC source I connected in series with choke 2, a coupling capacitor 3 connected to inductor 4, and also an inverter 3 bridge consisting of thyristors 5–8 counter diodes 9–12 and a switching chain 13 and 14 parallel to which two oppositely connected thyristors 15 and 16 are connected by cathodes connected to each other. The common point of thyristors 15 and 16 is the positive pole of the interelectrode gap (MEZ) 17, the negative pole of which is connected to the minus of the source 1 of direct current. The device works as follows. When control pulses are applied to the thyristors 5, 6 and 15, the oscillating current flows through the circuit formed by the elements 5, 14, 13, 6, 4 and 3. In addition, as a result of the thyristor 15 being turned on, another circuit is formed parallel to the power source 1 and the current flows through the thyristors 5 and 15 and the interelectrode gap 17. As a result, a constant voltage is applied to the MEZ 17 through the open thyristors 5 and 15. Then, with oscillatory overcharging of capacitance 14, the oscillating current of the inverter changes its direction and flows through the inductance 13, capacitance 14, open thyristor 5 (diode 10 is locked), capacitance 3 and inductance 4. The thyristor 5 cannot go out the load current flows through it directly. Only at the moment of time when the reverse oscillating current exceeds the amount of current flowing through the interelectrode gap, the thyristor 5 turns off and the diode 10 turns on. Thus, the interelectrode gap circuit will turn off. To form a longer pulse (burst) when the thyristor 5 is turned off, the thyristors of the second bridge are turned on. The cycle repeats and to continue it, the thyristors of the first bridge must be switched on, then the thyristors of the second bridge, and so on. up to the required total pulse length. The duration of the pulse applied to the electrode gap is controlled by removing the control pulses from the thyristors. In this case, both inverter bridges can remain switched on in short-circuit mode. The pause is also determined by the time inverter between turning on the thyristors and then turning off one of them. As a result, rectangular voltage pulses with a constant amplitude equal to the input voltage of the inverter are applied to the interelectrode gap. The duration and duty cycle of these pulses are easily adjustable if the inverter is performed operating at high frequency. If the inversion of the inverter is disrupted during a short-circuit interelectrode gap, the distribution capacitor 3 is recharged through inductance 4 and all the thyristors are locked. To reduce the voltage ripple at the inter electrode gap during the on state of the thyristors 5, 6 and 15, the inductance 4 is chosen such that at high frequency there is a resonance between it and the separator, 1 m. amplitude voltage pulses with a steep leading edge, with a wide range of control over their duration, frequency, and duty cycle, which improves its technological capabilities. The invention of the Istoshik power supply for electrophysical processing methods, which is connected to a direct current source through an input choke of a thyristor bridge with counter-parallel diodes on an LC circuit in a switching diagonal, another diagonal of which is divided into a coupling capacitor and protective inductance, that, in order to extend the functionality, two counter-sequential thyristors were inserted into the thyristor bridge, the anodes of which are attached to the LC-chain, and the common point is n thyristors their negative output DC source are output power source. Sources of information taken into account in the examination 1. USSR author's certificate Jf 300934, cl. H 02 M 5/42, 1969.