SU843148A1 - Generator of hign-frequency unipolar current pulses - Google Patents

Description

(54) GENERATOR OF SERIES OF UNIPOLAR HIGH-FREQUENCY CURRENT PULSES

one

The invention relates to converter technology and can be applied in the electrochemical processing of metals as a pulsed power supply.

A known current pulse generator comprising a series-phase single-phase inverter with a switching choke, connected to a power source via a control valve l}.

When using this J power supply, to obtain unipolar current pulses with an amplitude of several thousand amperes, parallel connection of a large number of thyristors or inverter cells operating on a common load with provision is required. their parallel operation, - which increases the size of the generators and limits the scope of their application. The frequency control method in these circuits is ineffective and is accomplished by changing the accuracy of current pulses.

The closest to the proposed generator of high-frequency current pulses contains a DC source, a bridge inverter with a LC commutating diagonal and counter-parallel diodes connected to a DC source through an input choke, and terminals for connecting the load connected

to the inverter through a coupling capacitor and protective inductance 2.

The device cannot generate unipolar current pulses, which is necessary for the electrophysical methods of metal processing. Also, for example, in electrochemical dimensional metal processing, there is a need for high currents at

low voltage load. The use of inverters in this case to obtain large currents requires parallel connection of inverter cells to the total load, and

a step-down transformer is required to obtain a low load voltage. Using a transformer allows you to get a low voltage on the load, but does not allow

to regulate the magnitude of the amplitude of current pulses with a constant duty cycle and reduces the efficiency of the generator as a whole.

The purpose of the invention is to expand the functionality of a known

devices.

The goal is achieved by the fact that the high-frequency current pulse generator is equipped with a bridge rectifier, a capacitor and a choke, the capacitor and the choke are connected in series with the coupling capacitor and protective inductance and connected to the AC diagonal of the bridge rectifier, and the terminals for connecting the load are connected to its diagonal constant nnogo current.

Scheme of the generator in 2-cell performance shown in the drawing,

. The generator contains a source of DC powering, to which inverter bridges 3 and oscillatory circuits 4 with a total load 5 are connected through input chokes 2. Serial circuits from coupling capacitor 6 and protective inductance 7 are connected to the power supply through input chokes. Each inverter bridge is formed thyristors 8–11, counter-parallel diodes 12–15, and a switching circuit formed by inductance 16 and capacitance 17. The oscillatory circuits consist of a capacitor 18 and a throttle 19. The load is included in oscillatory circuits through diode bridges formed by diodes 20-23 so that the diagonal of the alternating current of these bridges is connected to capacitors and throttles of oscillating circuits.

The generator works as follows.

When turning on the thyristors of the inverter bridge 3, an oscillating current 1 flows through the circuit formed by elements 3-7, whose frequency corresponds to the resonant frequency of the oscillating circuits. In circuits 18, 19, 20, 5, and 23, sustained oscillations ij, flowing through the diode bridge and loads, are excited. When the control frequency of the inverters is changed, it is possible to regulate the amplitude of the current flowing through the load over a wide range, by detuning the resonance in the oscillatory channels. At resonance, the amplitude of the current of the oscillating circuit i and the current in the load circuit is maximum and approximately. ; Q times the amplitude i ,, where

Q is the quality factor of the oscillatory circuit 4, which includes the load 5, the voltage on the load in this case is Q times less than at the terminals of the oscillating circuit.

The inverter in two-cell design allows. form a series of unipolar current pulses. In this cell inverter. Work with a phase shift of 90 e. hail, for a common load, the pause between a series of pulses is formed by turning off the inverter.

Using the proposed high-frequency inverter, through the thyristors of which relatively small currents flow (several hundred amperes), a series of unipolar current pulses of increased amplitude (several thousand amperes) and low voltage can be obtained on the load without the help of a high-frequency t-ranformator

Claims (2)

1. Author's certificate of the USSR 370001, cl. B 23 P 1/02, 1969, 2. USSR author's certificate number 300934, cl. H 02 M