SU1657300A1 - Pulse generator - Google Patents

Description

one

(21) 4366727/21

(22) 01/27/88

(46) 06.23.91. Bksh. G 23 (75) V0STs Tarasov

(53) 627 „373 (088.8)

(56) Pulse Generators. - M .: Energie, 1970, p.175, fig.8-6.

Gordeeva PG, Polkov IL, Rumntseva PL1., Sinenko V0V., Prushkina Yu0P. Powerful magnetic thyristor pulse generator / Experimental instruments and equipment, f ° 5, 1980, p. 1 18-119.

(54) PULSE GENERATOR

(57) The invention relates to a pulsed technique, in particular, to a source of pulsed currents for carrying out electroerosive processing and doping, which can be used in the construction of pulse generators

electroerosive machines and installations for electroerosone alloying. The purpose of the invention is to reduce the weight and size when used in EDM processing, as well as expanding the range of frequencies and pulse durations. The pulse generator contains a forming line 1, a switch 2, a control unit 3, a constant voltage source 4, a drive 5, a charge switch 6 made on a pulse-width modulator, windings 7 and 10 of a transformer 8 with a core 9. Introduction The rectifier 11 and the windings 12 and 13 of the transformer 8 made it possible to demagnetize the core 9 by charging and discharging 12 currents through the winding in opposite directions and thereby reducing the weight and size. 2 Il.

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The invention relates to a pulsed technique, in particular t sources of pulsed currents for the implementation of electrical discharge machining and doping, can be used in the construction of electroerosion pulse generators of machine tools and installations for electroerosive alloying.

The invention is a reduction in mass and dimensions, in particular when used for EDM, as well as an extension of the range of frequencies and pulse durations.

Fig. 1 is an electrical circuit diagram of the device;

2 shows the construction of a transformer.

The pulse generator contains the forming line 1, the discharge switch 2, the control unit 3 and the series-connected constant-voltage source 4, the accumulator 5, the charging switch 6 performed on the pulse-width modulator, the first winding 7 of the transformer 8 with the core 9 is inductive connected to the second winding 10 transfer№

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Matora 8, while the output of control unit 3 is connected to the input of a pulse width modulator, rectifier 11 and third and fourth windings 12, 13 of transformer 8. Second winding 10 is connected via series-connected rectifier 11 forming line 1, third winding 12 transformer to the input of the discharge switch 2, the output of which is connected to the output of the rectifier 11, the output and control input of the discharge switch 2 are connected respectively to the input and the second output of the unit 3 controlled, the fourth winding 13 of the transformer 8 is connected and to the electroerosion gap 14, the core 9 of the transformer 8 is made with a closed cavity, inside and along which the turns of the first and second windings 7, 10 of the transformer 8 are located, and the third and fourth windings 12, 13 are perpendicular to them outside. 13. The core 9 is made in the form of a hollow torus consisting of two identical leaves adjacent to each other with a gap in the plane of the torus. The fourth winding 13 is made in the form of a volumetric vetch and covers the third winding 10, and the core 9 of the transformer 8 may be made of a magnetic isotropic material, for example ferrite. Forming line 1 can be configured to adjust the parameters of the pulses by switching sections depending on the requirements of the erosion treatment technology to the duration and steepness of the edges of technological current pulses

Rectifier 11 is connected via successive charging choke and winding 12 to line 10 The second output of rectifier 11 is connected through a sequential discharge switch 2 and winding 12 to line 1, forming a discharge circuit.

A high-frequency pulse thyristor can be used as a bit switch.

Spark discharge electrodes are connected to winding 13, forming an erosion gap.

Unit 3 with its control output is connected to the modulator 6 with the provision of galvanic isolation (for example, optocouplers). When performing the modulator 6 for supply with the winding 7 one

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A pulsed pulse, which simplifies the modulator 6, in the core 9 a non-magnetic gap is necessary, preventing the core from saturating from magnetizing it in one direction. The non-magnetic gap can be formed by a gasket 15 in the form of a thin ring located between two identical flaps adjacent to one another, forming a core 9,

The winding 7 and the winding 10 can be placed in covers 16, made in the form of ring bases, on the periphery of which there are flexible vaulted corrugations, which are closed with their free ends when they are pressed by the niches of the cusps of the magnetic circuit. Due to the high dielectric properties of the core ferrite 9 and the maximum distance between the joints of the corrugations on the inner surface of the chip of the insulation of the insulation between the windings 7 and 10, is almost determined by twice the wall thickness of the ring base. This insulation provides reliable galvanic isolation of the mains supply from the common wire of the generator and increased operational safety in production conditions.

The flaps of the core 9 can be shrunk by insulating 17, consisting of a fluoroplastic tape wrapped around a torus section with an adhesive layer. Since the torus cross section is a circle, it is possible to evenly distribute the tension force of the insulation during winding (for example, in comparison with the rectangular cross section profile), which improves the quality of the insulation and allows its thickness to be reduced with all other conditions being equal. Winding the insulation 17 simultaneously with the core 9 core flaps along the torus length, prepares its surface for winding winding 12 (damage to the windings 12 by the edges of the gap of the core 9 is excluded).

The winding 12 may be covered on both sides by electrically conductive (for example copper) sash, connected to provide electrical contact on the periphery by soldering (in figure 2 to the left of the toroid axis) inn screws (right), forming a volumetric coil of the winding 13. Joining of the cusps of the coil of the winding 10 on the periphery provides reliable electrical contact and

low ohmic resistance of a coil, since at the periphery the current density in the coil body is the same as in the central part, and the area of the contact surfaces is much larger, which reduces the requirements for contact resistance. In the working range of the pulse currents for electrons, the core 9 is made toroidal (without corners), the winding 12 also completely covers the surface of the core 9, which provides a strong

troeroerion alloying 0,2 ... 5 kA, 0 electromagnetic link winding 12

and electroerosive processing of 0.015 ... 1 kL, such an implementation of the winding 10 ensures its simplification, since a multi-turn winding on such a current with a small inductance of dissipation is difficult to produce. At the same time, it is always possible to calculate the core and the remaining windings for the used current emitting durations of technological current O, 8 ... 600 X, provided that the output voltage specified by the processing technology is obtained on a single turn and is volumetric. Transformer1 8 as a whole is also simplified due to the use of this volumetric coil as a transformer casing, which ensures the tightness and protection of windings against the factors of the electrical process. In the central part of the upper flap of the volumetric coil of the winding 13 there is a bottom, in the center of which a conductive pin 18 is made. The lower flap also has a bottom on which a hollow conductive cylinder 19 is located, which is located coaxially with it. The central part of the windings of the coil of the winding 10 and the elements 18 and 19 are insulated for the operating voltage of the erosion gap by solid insulation (a orthoplastic sleeve). The plug 18, which is the inner core of the coaxial conductor, and the cylinder 19, is the outer core of the conductor, are connected to the electrodes of the erosion gap 14. At the same time, the dissipation inductance of the transformer 8 is minimal, since the electrically conductive folds of the coil of the winding 10 completely cover the surface of the core 9 , transition to a solid coaxial connection from elements 18 and 19, directly connected to the EDM load. This short circuit of pulses of power current provides as a small inductance of 20

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with the core 9 and the winding 13, loaded on the erosion gap 14. This contributes to the transmission without distortion of the shape formed by the line 1

15 current pulses from the winding 12 in the discharge circuit of line 1, into the winding 10 and the erosion gap 14. By changing the duration of the generated pulses to the direction of decreasing before the processing starts by switching the sections of line 1, i.e., the range of the generated pulse durations, i.e. to expand the technological capabilities of the generator, because, thanks to the proposed solution, the distortion of the pulse shape is significantly reduced. The formation of short impulses allows setting the control unit 3 to the start of processing to increase the frequency of the process current impulses and, with a given power in the erosion load, improve the quality and performance of the electro-erosion treatment

35 and doping.

The core 9 in the cross section of the hollow toroid can have a profile thickened towards the center of the torus, as a result the magnetic material of the core 9 in the generator has a constant electromagnetic load per unit volume. This makes it possible to establish in the manufacture of the generator the optimal magnitude of the magnetization reversal field for this

45 of the type of material of the core 9 and thereby fully utilize its capabilities, reducing the weight and dimensions of the generator.

The location of the turns of the windings 7, 10,

50 and turns of the windings 12, 13 perpendicular in space provides for the reversal of the core 9 in two mutually perpendicular directions.

55 This allows you to use the volume of the magnetic material of the transformer I in both the charge and discharge circuits of the forming line 1, to use all the magnetic material of the core 1

sowing, and small active losses, which reduces the distortion of the shape of the generated current pulses and losses in the working circuit of the generator.

By making the core 9 toroidal (without corners), the winding 12 also completely covers the surface of the core 9, which provides a strong

the electromagnetic coupling of the winding 12

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with the core 9 and the winding 13, loaded on the erosion gap 14. This contributes to the transmission without distortion of the shape formed by the line 1

5 current pulses from the winding 12 in the discharge circuit of line 1, into the winding 10 and erosion gap 14. By changing the duration of the generated pulses to the direction of decreasing before the processing starts by switching sections of line 1, i.e. to expand the technological capabilities of the generator, because, thanks to the proposed solution, the distortion of the pulse shape is significantly reduced. The formation of short impulses allows setting the control unit 3 to the start of processing to increase the frequency of the process current impulses and, with a given power in the erosion load, improve the quality and performance of the electro-erosion treatment

5 and alloying.

The core 9 in the cross section of the hollow toroid can have a profile thickened towards the center of the torus, as a result the magnetic material of the core 9 in the generator has a constant electromagnetic load per unit volume. This makes it possible to establish in the manufacture of the generator the optimal magnitude of the magnetization reversal field for a given

5 of the type of material of the core 9 and this fully use its capabilities, reducing the weight and dimensions of the generator.

The location of the turns of the windings 7, 10,

0 and turns of the windings 12, 13 perpendicular in space provides for the reversal of the core 9 in two mutually perpendicular directions.

5 This allows using the volume of the magnetic material of the transformer I in both the charge and discharge circuits of the forming line 1, to use all the magnetic material of the core 1

almost all the time of the generator and apply one transform | torus 8 instead of two, reducing the weight and size of the generator.

The pulse generator for EDM works as follows.

A constant voltage source 4 provides the charge current of the accumulator 5 (made in the form of a capacitor), which allows pulsation to coincide with the mains frequency.

After the accumulator 5 is charged, the modulator 6 periodically supplies the winding 7 with a pulsed unipolar (or two-polar in another embodiment) current. The width of the pulses is automatically adjusted by the modulator 6 because of the condition that the current in the winding 7 is constant averaged over several pulse periods.

The leakage through the winding 7, the pulse current causes a magnetic flux in the core 9, directed around the turns of the winding 7. The magnetic flux crosses the nonmagnetic (nonmagnetic) gap with a gasket 15, which prevents saturation of the core 9. The core 9 covers the turns of the winding 10, current flows in the winding 10 which is rectified by the rectifier 11. In this case, the full-wave rectification makes it possible to rectify the current of both the main pulse and the current from the counter-electromotive force of the other polarity arising from the electromagnetic scattering of the core 9 with a gap in this direction ui The energy transformed from the winding 7 to the winding 10 of the main pulse and the energy stored during this pulse in the dissipation inductance of the transformer 8 enters the forming line 1, charging it. Charging the line 1 with a constant averaged current reduces the charging time by increasing the permissible frequency of the generated pulses.

From the output of the rectifier 11, the averaged to a given time voltage of the charge line 1 is fed to the input of the control unit 3. After reaching the line 1 charge voltage specified before processing, determined by the required pulse energy according to the processing technology, block 3 turns off the modulator 6, the current pulses in the winding 7 stop. Then im10

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16573008

The start pulse from unit 3 turns on the discharge switch 2. The discharge current of the forming line 1 flows through the circuit: line 1, switch 2, winding 12, line 1 "This causes the core 9 to be re-magnetized in a different spatial direction and the current is induced in winding 13 technological impulse flows through the circuit: winding 12, pin 18, erosion gap 14, cylinder 19, winding 13, producing electroerosive processing.

After the passage of this current, switch 2 is turned off (for example, the thyristor is closed due to the resorption of minority carriers at the transitions as a result of reducing the forward current to the value of the holding current or when the polarity of the applied voltage is changed due to some mismatch line), the current in the erosion gap 14 between the discharge electrodes ceases.

Then, the unit 3 turns on the modulator 6 and the forming line 1 is charged from a constant voltage source 4. Thus, the generator forms a sequence of erosion pulses in the discharge.

The possibility in the proposed generator of magnetization reversal of the volume of the magnetic core 9 n of two mutually perpendicular directions allows its use both during the charging of the forming line 1 and during the discharge. This allows the use of one transformer 8 for the power and pulse circuits of the generator, which reduces the weight and dimensions of the generator.

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In the process of charging and discharging the forming line, the charge and discharge currents of the protocap on the winding 12 are in opposite directions, which ensures demagnetization of the core 9 after the passage of the discharge pulse in this direction. An additional non-magnetic gap in this direction is not required, which allows for the greatest magnetic coupling of the core 9 to the windings 12 and 13 and to significantly reduce the shape distortion during the transmission of a current pulse from the forming line 1 to the erosion gap 14. The gap in the other

In the process of charging and discharging the forming line, the charge and discharge currents of the protocap on the winding 12 are in opposite directions, which ensures demagnetization of the core 9 after the passage of the discharge pulse in this direction. An additional non-magnetic gap in this direction is not required, which allows for the greatest magnetic coupling of the core 9 to the windings 12 and 13 and to significantly reduce the shape distortion during the transmission of a current pulse from the forming line 1 to the erosion gap 14. The gap in the other

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The direction of the strand is not affected by the magnitude of this connection.

Performing the winding 13 in the form of a volumetric coil makes it possible to simultaneously shield the electromagnetic circuits of both the charging circuit and the discharge circuit of the Normalizing line and thereby exclude high-frequency electromagnetic radiation into the surrounding space. This further simplifies the generator and reduces its weight and dimensions, since additional separate screens on the power and pulse transformers are not required, and the volumetric coil at the same time performs its main function — the creation of a power technological current in the erosion gap of the arrester. transformer.

The execution of the charge and discharge circuits of the forming line with small scattering inductances, as well as the volumetric coil in the form of flaps, which in the central part form a coaxial current lead to the erosion gap of the spark discharge, significantly expand the ranges of generated frequencies and pulse durations and technological capabilities of the generator during EDM processing and doping. Making a gap in the toroid plane makes it possible to use the same sash to form the core, which simplifies the manufacture of ferrite products and the generator in

scrap.

Claims (2)

1. A pulse generator containing a forming line, a discharge switch, a control unit and a serially connected source of 10 ten five 0 five 0 five 0 voltage, drive, charge switch, made on a pulse-width modulator, the first winding of a transformer with a core, inductively connected to the second winding of a transformer, the output of the control unit is connected to the input of a pulse-width modulator, characterized in that in order to reduce the weight and size when used for EDM processing, as well as to expand the range of frequencies and pulse durations, a rectifier, a third and a fourth transformer winding, a second winding are introduced into it The transformer is connected via a series-connected rectifier, forming a line, the third winding to the input of the bit switch, the output of which is connected to the output of the rectifier, the output and the control input of the bit switch are connected respectively to the input and the second output of the control unit, the fourth winding of the transformer is connected to the first and second electrodes of the electroerosion gap, the transformer core is made with a closed cavity, inside and along which the turns of the first and second windings are located transformers, which are perpendicular to the third and fourth windings placed outside. 2. The pulse generator according to claim 1, characterized in that, for the purpose of its simplification, the core is made in the form of a hollow torus consisting of two identical flaps adjacent to each other with a gap in the plane of the torus, and the fourth winding is made in the form volumetric coil and covers the third winding. 1 n 12 Yu 1