SU1290221A1 - Device for exciting electromagnetic field in geoelectric surveying - Google Patents

Abstract

The invention relates to exploration geophysics, in particular, to devices for driving an electromagnetic field in the earth. The purpose of the invention is to increase the service life and simplify the design of the device. The goal is achieved by introducing into the device an additional electronic key with a parallel-connected ballast resistor and a reversing converter. The AC unit produces a stabilized voltage with a stabilized frequency. The inductive-capacitive converter stabilizes the current, and the transformer and rectifier transform and transmit alternating current. As a result, a constant voltage is applied to the thyristor inverter. 1 il. i (О С INS QD О ю ю

Description

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The invention relates to exploration geophysics, in particular, devices for exciting an electromagnetic field in the earth, and can be used in conjunction with measuring systems for geoelectric studies using artificially generated electromagnetic fields.

The purpose of the invention is to increase the service life and simplify the design of the device.

The drawing shows a block diagram of the device.

The device contains a series-connected AC unit 1 and an inductive-capacitive converter 2, made in a T-shaped circuit with varying capacitance, an additional electronic switch 3 and an electronic switch 4, made on anti-parallel thyristors VTj

VT, while the ballast resistor R 5 reversing converter 5, which consists of two counter-parallel controlled bridge terminals VT, VT, load Z, and a control unit 6 connected to blocks 2 - 5, are connected in parallel to the key 3 In order to simplify the description of the device, a single-phase device is shown in the block diagram. In fact, the device contains a three-phase circuit and a three-phase AC unit. I

The device works as follows.

An AC unit produces an alternating stabilized voltage with a stabilized frequency. Inductive-capacitive converter 2 stabilizes the current in the load Z j and at the same time by changing the capacitance can change its value. In this case, the voltage on the load may exceed the voltage produced by the unit of alternating current 1.

In the control unit 6, the modes of operation of the device are set and monitored: current pulses of the polarization without pauses or with pauses in the load Zj,.

To obtain a positive polarity of the current in the load Z, the key 3 is in the open state due to the continuous supply to the control

Relative electrodes with respect to high-frequency unlocking voltage pulses, the frequency of which is chosen much higher than the frequency of the AC unit 1.

At the same time, similar unlocking voltage pulses are applied to the control electrodes of the controlled bridge rectifier VTj of unit f. As a result, the thyristors of the rectifier VT open and a current flows in the load 2, 1 (indicated by a solid arrow). To obtain a negative current polarity, the supply of 1: 1x voltage pulses to the bridge rectifier VTj of unit 5 is stopped and the supply of similar relatively high-frequency voltage pulses to the control electrodes of the controlled bridge rectifier ICD of block 5 begins. As a result, the rectifier VT spontaneously turns off, and the thyristors of the rectifier VT open and a current flows through the load Z (indicated by a dashed arrow).

To create dead-pause, the same unlocking voltage pulses are applied to the control electrodes of the key 4 VT and simultaneously the supply of the unlocking voltage pulses to the key 3 VT (and the VT switch; block 5. As a result, the key 3 and the rectifier VT spontaneously off In this case, the voltage on the block 5 is zero and the current in the load Z is absent, and the AC unit i is loaded on the ballast resistor R 6 and maintains the steady state of operation. Dp of stopping the dead time on command from the control unit 6 unlocking imp lsy voltage again supplied to the key 3 and VT on one of the rectifiers unit 5. I

During the work of the three-phase device

on a load-pole having a. inductive resistance, in the mode of different-polarity pulses, the duration of the current switching front in the load varies from 1/3 to 1/2 of the sinusoidal period of the AC unit and depends on the load parameters , on and off time: thyristors. Since the measuring signal accumulates in the measuring systems, the duration of the current switching edge

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when the device operates in the dead time mode, the duration of the current switching edge at a transition from positive or negative polarity is determined by constant values, depending on the thyristor on-time and load parameters.

The device has a simpler design due to the combination of two functions in the reversing converter - the rectification and switching of the current in the load. The spontaneous switching on of the thyristors simplifies their switching and makes it possible to remove the restrictions from the parameters of the load, which has mainly active-inductive resistance.

Claims (1)

Invention Formula An apparatus for driving an electromagnetic field in geoelectrical exploration comprising GO connected AC unit and inductive-capacitive converter, electronic key and load, as well as a control unit, characterized in that, in order to increase the service life and simplify the design, an additional electronic key with a parallel ballast resistor connected, a reversible converter, with this output of the inductive-capacitive converter is connected in series with the electronic key and an additional electronic key, 15 the input of the reversing converter is connected in parallel with the electronic key, the output is loaded, the control unit is connected to the inductive-capacitive converter with an electronic key, 0 additional electronic key, reversible transducer, and the capacitance of the capacitor inductive-capacitive transducer is made variable. Compiled by I.Abramova Editor N.Gorvat Tehred A.Kravchuk Proofreader E.Roshko  - - -- - - - - --.one,"."... -- - - ---."- - - - - - - - - . - - Order 7896/42 Circulation 752 Subscription VNSHPI USSR State Committee for inventions and discoveries 113-035, Moscow-, Zh-35, Raushsk nab., 4/5 . Production and printing company, Uzhgorod, Projecto st., 4.