SU885779A1 - Induction furnace control apparatus - Google Patents

Description

one

The invention relates to a technique for controlling high-frequency electrothermal installations, in particular quartz-smelting furnaces with tube generators.

The closest to the proposed technical essence and the achieved result is a device containing a power source (machine generator), a high-frequency circuit consisting of capacitors and an inductor with a high-voltage transformer, program block, preamplifier, amplifier. converter (feedback unit) and comparison device l.

The principle of operation of the known device is that the signal received from the sensor (according to Rogowski), proportional to the current in the loop (at a constant frequency), goes to a converter, where it can be converted by using squares

The signal is proportional to the power of the circuit, and hence to the power of the heater (at a constant frequency), and is then fed to the comparator. The error signal from the comparison device through the amplifiers is supplied to the control of the power source by the high-frequency generator.

to

The power released in heating, in a high-frequency furnace, can be expressed by the equation Pf K S Vf, where K is the proportionality coefficient, S is the current in the inductor, f is the frequency of the loop current.

The signal received in the sensor (according to Rogowski’s cross) can be expressed according to formula E.

.Sf and when erecting it in

quad

Claims (1)

rat. - according to the formula E j K -S .f4 Such a signal is fed to the comparison device during regulation. 8 As follows from a comparison of the two. the mathematical dependences of P and E with a change in the frequency of the current in the circuit during regulation introduces an error proportional to. The analysis shows that for lamp generators of type VChIZ-160 / 0.066 and VCGZ-160 / 0.066 for permissible changes in the frequency of the current + 7.9-6.6 kHz, the error in the regulation is + 15.8-13.2% (2% frequency changes for each kHz), which is confirmed by experimental work. The known system of automatic regulation does not ensure reproduction of a predetermined temperature technological process. The purpose of the invention is to improve the accuracy of regulation. This goal is achieved by the fact that in a known device containing a program block, a comparison device and a feedback node with a sensor and a quad converter, in a feedback node the current frequency division blocks of degree 3 are included in the electrical signal circuit after the quad converter (2), to which the frequency meter and the square root extractor from the frequency of the current are connected, and the dividing unit is connected to a comparison device. The drawing shows a block diagram of the proposed induction furnace control device. A high-frequency power supply 1 is connected to an oscillating circuit consisting of an inductor 2 and a capacitor bank 3. A current sensor 4 (along Rogowski's circuit is connected to an inductor circuit. The current sensor output is connected to a quad converter 5 and a frequency meter 6, the signals of which arrive on the square-root extraction block 7 of the frequency and the division block 8. The output of the square-root extraction block 7 and the division block 8 are also connected to the division block 9. The feedback node and the program block 10 are connected to the equalizer 11. The output signal of the comparator is fed to the regulator 12, which is connected to the power source. The principle of the device operation is as follows: In the current sensor 4, an alternating current emf is induced proportional to 4 the current of the oscillating circuit} and the frequency equal to the current frequency The signal from the current sensor is fed to the converter-quad 5, where it is squared, proportional to the product of the circuit's power and the frequency in the square, and then this signal goes to the dividing unit 8. Parallel to the converter-quadrant, the signal from the current sensor is fed to the meter 6 of the current frequency and from the frequency meter of the current to the square root extraction unit 7. From the frequency meter and the square root block, the signals are sent to the corresponding blocks of divisions 8 and 9, where the signals from the quadrant are divided by the current frequency, and then by the square root of the frequency. The frequency-corrected signal, proportional to the power of the heater, and the signal from program block 10 are sent to the comparison device 11, and then the error signal is fed to the controller 12, which controls the power source 1. The effect of the proposed invention is that it allows to regulate the temperature process of high-frequency quartz-furnace electric furnaces according to a given program with an accuracy of ± 1%, which, in turn, will stabilize the geometric parameters of the quartz pipes produced on the electric furnace and increase suitable products. Claims An induction furnace control device comprising a program block, a comparison device and a feedback unit with a sensor and a quad converter, characterized in that, in order to improve the control accuracy, in the feedback node into an electrical signal circuit after the quad converter successively included are frequency dividing units to which they are connected, respectively, as dividers, a current frequency measuring unit and a square root extractor unit from the current frequency. 5885779 3, „le „„, „™„ „and crap„ ™ a „- - - -в; - ;; - --G-PeG common device. Electrotherms sources of information. Collector. M. VNIIESM information standardstand into account when examining electro, 1968, vol. 75, 76, s.we OU.