# The method of excitation of oscillations in the electrical circuit and device for its implementation

(57) Abstract:

The invention relates to the field of generating high-frequency damped oscillations and can be used in welding technique. The technical result is to obtain a powerful electrical oscillations in circuits that when using the welding machine will increase its capacity several times. The technical result is achieved by the use of the method of excitation of oscillations in an electric circuit, which consists in the generation of oscillations by control signal to control the excitation of vibrations, which by impact excitation of the electric circuits and the generation of harmonics of a higher order than the main fluctuations, form their sequence of resonance currents and resonance voltages. A device for implementing this method includes a high-frequency transformer, thyristor switch, power supply, pulse transformer, the resistor, the phase-shifting unit, two capacitor and inductance. 2 C. p. F.-ly, 4 Il. The invention concerns a method of producing a damped high frequency oscillations and can be applied, in particular, in the welding technique, as the oscillator in the shock excitation of oscillations in an electric circuit", described in and.with. N 292592 CL H 03 B 11/08, characterized by the fact that for impact excitation of oscillations in the electrical circuit used explosion of metal wires. Moreover, in order to accurately capture the moment of explosion, electrical circuit, wire explosion trigger light beam of the laser. Using this method will increase the capacity of excited vibrations, because you can use thicker wire without compromising temporal characteristics.The known device, is selected as the analog "Device for excitation of the oscillating circuit" described in the application Germany N 3733943, CL H 03 B 11/04, characterized by the fact that the oscillating LC circuit through the managed key is connected to the constant current source. Managed from the control circuit key, depending on signal processing oscillating circuit, carries out oscillations in the circuit.The disadvantage of the presented similar is the fact that the plug resonant circuit when the shock excitation, develops capacity weak electrical oscillations, as well as the complexity of the industrial applicability of the method.The closest in technical essence and the achieved positive effect to declared the application Germany N 3733943, CL H 03 B 11/04. The method of excitation of oscillations in an electric circuit, which consists in the generation of oscillations by control signal that controls the excitation of vibrations.Essential for the prototype is the connection of the oscillating LC circuit in series or parallel to the DC source through a managed key. Managed key, depending on signal processing oscillating circuit, disconnects and connects the resonant circuit to the power source, thereby provides the excitation of the oscillating circuit and the control circuit determines the degree of damping of the oscillating circuit.The closest in technical essence and the achieved positive effect of the claimed device is selected as a prototype Generator excitation oscillation, described in U.S. patent, N 4837525, CL NCI 331-165.The device excitation of oscillations in an electric circuit containing a high-frequency transformer, the end of the primary winding of which is connected to the first output of the thyristor switch, the second end of which is connected to the first output of the first capacitor, the first output power source and to the end of the secondary Eternulo switch.The disadvantage of the prototype is that plug-in oscillation circuit, when the shock excitation there is insufficient power fluctuations. For example, when using the circuit as an oscillator, the latter, by shock excitation, develops insufficient to initiate and stabilize the welding arc power.The technical result of the invented method is to obtain a powerful electrical oscillations in the circuits, the use of which in the oscillator, made in the form of the invented device, the welding machine will increase its capacity in a few times, respectively, the degree of ionization of the arc gap.The technical result is achieved due to the fact that in the method of excitation of oscillations in an electric circuit, which consists in the generation of oscillations by control signal that controls the excitation of vibrations, unlike the prototype, in electric circuits form a sequence of resonance currents and resonance voltage by shock excitation and generation of harmonics of a higher order than the fundamental oscillation, the amplitude of which is determined in accordance with the relationship:Rugova the undamental;

the amplitude of the resonance voltages;

n is the number of harmonics;

- phase fundamental wave.The technical result is achieved due to the fact that the device excitation of oscillations in an electric circuit containing a high-frequency transformer, the end of the primary winding of which is connected to the first output of the thyristor switch, the second terminal of which is connected to the first output power source and to the end of the secondary winding of the pulse transformer, which has its beginning through the resistor connected to the control electrode of the thyristor switch, unlike the prototype, it introduced the phase-shifting unit and the thyristor switch is made symmetrical, and the second terminal of the first capacitor is connected to the beginning of the primary winding of the high-frequency transformer and a second capacitor connected to the first output inductance, the second output of which is connected to the second output power source and to the first output of the phase-shifting unit, the second terminal of which is connected to the first output power source and to the end of the primary winding of the pulse transformer, which is connected to the third output of the phase-shifting unit.The invention has penned the account of the formation sequence of resonances shock excitation circuits, create voltage shock excitation with a wide frequency spectrum. This voltage has a frequency f

_{1}and f

_{2}close to the natural frequencies of both oscillatory circuits, which is a sequence of resonances, first resonance currents, then the resonance voltage.The essence of the invention lies in the fact that the invented method and device for its implementation ensures the formation of the primary winding of the high voltage transformer, the value of which is K-times larger than the voltage of the AC power source, K is determined by the quality of the serial circuit. This will greatly increase the power of the vibrations in the high frequency transformer. The application of the invented device as an oscillator welding machine greatly increases the power of ionization of the arc gap. Control signal shifts the phase of cosinusoid AC voltage than regulates power fluctuations in the high frequency transformer, respectively, the power of ionization of the arc gap.In Fig. 1 shows a timing diagram of the operation of the method of excitation of oscillations in e is the amplitude of the resonance voltage, - phase fundamental wave is equal to zero.In Fig. 2 shows a partial diagram of the voltage of the shock excitation circuit according to Fig. 1. Including a and B shows the sequence of resonances.In Fig. 3 shows a timing diagram of the operation of the method according to Fig. 1 control phase.In Fig. 4 shows an electrical schematic diagram of a device impact excitation of oscillations in the electrical circuit. Moreover, the timing diagram of operation of the method corresponds to the point Q of the device according to Fig. 4.The method is as follows. To implement the sequence of resonances to the series-connected parallel and series resonant circuits served alternating voltage. Through managed key in circuit parallel resonant circuit formed of shock excitation circuit. As a result, the oscillating circuits is formed by the voltage U(t) according to Fig. 1 complex shapes and a wide spectral composition, an analytical expression which corresponds to the dependencies in the form of Fourier series

< / BR>

where the phase of the fundamental wave = 0

Analytically this function can be represented as su is and the second bipolar sequence of rectangular pulses with a period equal to the period of cosinusoid, and analytically represent Fourier series, as

< / BR>

where is the amplitude of the rectangular pulse.On newly formed as a result of shock vibration excitation harmonics generated sequence of resonances, and the first resonance currents, as in the parallel circuit is set driven key, respectively, there is a way to pass the DC, then the resonance voltage in a sequential circuit.According Fig. 1 the line segment AB voltage U corresponds to the resonance currents, and line segment BC is the resonance voltage. Next, the curve CA

^{1}(more precisely, cosinusoid) correspond to the application of alternating voltage to the series-connected circuits. While sections A

^{1}B

^{1}and B

^{1}C

^{1}similar to the above process with the other polarity.In Fig. 2 presents a fragment of the voltage of the shock excitation of oscillations in the circuits according to Fig. 1 including A and B show the sequence of resonances.From so A to T. B decays cosinusoid characterizes the resonance currents in the parallel con is the result of shock excitation circuits, the frequency of which is close to the natural frequency of the parallel circuit. The damping rate of the oscillations is determined by the losses in the circuit and, mainly, by the time of closing of the control key

_{C}. After the end of the resonance current starts the resonance voltage in the series resonant circuit. From T. B, so C decays cosinusoid characterizes the resonance voltages carried out with a frequency f

_{2}. Moreover, the offset of the coordinate axis value characterizes the quality factor of the oscillating process of sequential circuit and is determined by the parameters of the circuit elements. The resonance voltage is carried out on the harmonica, formed by shock excitation circuit, the frequency of which is close to the natural frequency of the series resonant circuit.The damping rate of the oscillations is determined by the losses in the sequential circuit.Changing the parameters of oscillatory circuits, according to their own frequency, change the frequency at which the sequence of resonances. Thus the q of the circuits can be increased to 100 units and above.In Fig. 3 shows a timing diagram of the operation of the method according to Fig. 1 and 2 with the I impact excitation MNEO corresponds to the analytical dependence according to equation (1), for the case = 0, and provides for the formation of the maximum voltage at the resonance currents. The displacement of the main harmonics left in the form of voltage shock excitation takes the form of the curve labeled 1 MNKO, according to Fig. 3 and analytically written according to equation (1). The voltage generated when the resonance current is reduced in proportion to the phase saving and accordingly is OK, and the voltage generated in the resonance voltage remains unchanged.When the shift of the main harmonic on /2 form voltage shock excitation takes the form of the curve marked 2 MNLO, according to Fig. 3 and analytically written as

< / BR>

The voltage generated in the resonance currents, is reduced to the value OL.When the shift of the main harmonic on the right form of voltage shock excitation takes the form according to the curve marked 3 MNKO. The value of the voltage generated in the resonance currents corresponds to the value of KO according to Fig. 3.The device for implementing the method illustrated in Fig. 1 and 2, shown in Fig. 4, includes a source 1 of alternating voltage, which is connected to the phase-shifting 2 by block, with catesory connected to the source 1 of alternating voltage through a symmetrical thyristor 7 switch, and the output of the phase-shifting block 2 through pulse 8 transformer and the resistor 9 is connected to a control electrode of the symmetric 7 thyristor switch. Moreover, the secondary winding 6 high frequency transformer has output terminals 10 that connects to the load. The phase-shifting block 2 contains the serial connected resistor 11, the potentiometer 12 and the capacitor 13, to the midpoint of which is connected symmetric 14 dynistor.Capacity 5 and 6 high frequency transformer form a parallel resonant circuit which is formed by the resonance currents and the inductance 3, 4 capacity and capacity 5 form a series resonant circuit, which is formed by the resonance voltage.The device according to Fig. 4 operates as follows. The source 1 of alternating voltage generates a voltage, in which a series resonant circuit is divided into capacitive divider is proportional to the tanks 4 and 5, and the point corresponds to equation (2). The phase-shifting block 2 through dynistor 14 generates a short pulse through the pulse transformer 8 and the resistor 9 is supplied to a control electrode of the symmetric 7 thyristor switch. Thyristor 7 commuted for constant current through primary winding 6 high frequency transformer. In this case, there is a resonance current and voltage from so A is moved in T. B according to the diagram of Fig. 2 during

_{C}which corresponds to the time of closing of the thyristor 7 switch. The resonance currents will be held at a frequency of

< / BR>

where L

_{6}- inductance high-frequency 6 of the transformer;

C

_{5}- capacity capacitor 5 according to Fig. 4.After the thyristor switch closes, there will come a resonance voltage in a sequential circuit. In this case, the voltage from so B will move in so C according to the diagram of Fig. 2. The resonance frequency of the voltage is defined as

< / BR>

where L

_{3}the inductance element 3 circuit according to Fig. 4;

C

_{4}and C

_{5}- capacity capacitors 4 and 5 of the flow chart according to Fig. 4,

The decrement of damping of the oscillatory process in a series resonant circuit is determined by the losses in the circuit. The voltage BC chart according to Fig. 1 is determined by the q of the circuit and depends on the parameters of the inductor 3 and the capacitors 4 and 5. All diagrams shown in Fig. 1 ... Fig. 3 correspond to the voltage in the Q so the device according to Fig. 4. Further, when changing the polarity of the AC voltage in Posidonia variable resistor 12 in the phase-shifting 2 the unit value of the phase shift of damped pulses symmetric 7 thyristor switch relative to the main harmonic oscillation according to Fig. 3, it is possible to regulate the voltage supplied to the primary winding 6 high frequency transformer, respectively, can be adjusted within certain limits the power of high-frequency oscillations, with output terminals 10 of the device according to Fig. 4.The positive effect of the invention is that the method and the device for its implementation provide the formation of the primary winding of the high voltage transformer, the value of which is K - times larger than the voltage of the AC power source, K is determined by the q of the circuit. This will greatly increase the power of the vibrations in the high frequency transformer. The application of the invented device as an oscillator welding machine greatly increases the power of ionization of the arc gap. Control signal shifts the phase of the alternating voltage regulated than the high-frequency power transformer, respectively, the degree of ionization of the arc gap.Literature

1. USSR author's certificate N 292592, H 03 B 11/08, 1975.2. The application of Germany N 3733943, H 03 B 11/04, 1989.3. U.S. patent N 4837525, 331 - 165, 1989.4. Bessonov L. A. Theoretical basis is Torah, consisting in the generation of oscillations by control signal that controls the excitation of vibrations, characterized in that act to a stimulating pulse to the parallel and serial circuits for forming their impact excitation and create harmonics higher than the fundamental oscillation, the order in which a sequence of resonance currents and resonance voltages.2. The device excitation of oscillations in an electric circuit containing a high-frequency transformer, the end of the primary winding of which is connected to the first output of the thyristor switch, the second terminal of which is connected to the first output of the first capacitor, the first output power source and to the end of the secondary winding of the pulse transformer, which has its beginning through the resistor connected to the control electrode of the thyristor switch, characterized in that it introduced the phase-shifting unit, the thyristor switch is made symmetrical, and the second terminal of the first capacitor is connected to the beginning of the primary winding of the high-frequency transformer and a second capacitor connected to the first output inductor, the second output of which is connected to the second output power source and to the end of the primary winding of pulse transformer, the beginning of which is connected to the third output of the phase-shifting unit.

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FIELD: radio engineering, communication.

SUBSTANCE: method of controlling attenuation in an oscillatory LC circuit is based on connecting an additional resistor ρ<<r to the circuit between the earth and an inductance coil, where r is the active resistance of the coil, and introducing special initial conditions for generation of controlled oscillations. External emf is introduced into the circuit, the value of which is equal to the voltage across the resistor amplified k times without inversion and periodisation of the launch modes and the initial position. The required nature of attenuation is established and observed by controlling the equivalent resistance of the circuit r*=r-ρ(k-1); if r*>0 the process is attenuating, if r*=0 the process is not attenuating and if r*<0 the process is rising.

EFFECT: establishing the required nature of attenuation in controlled oscillations.

2 cl, 1 dwg