Дослідження на моделі в MatLab спектру вихідної напруги та струму однофазного тиристорного регулятора за роботи на RL-навантаження

І. М. Голодний, О. В. Санченко

Анотація


STUDY ON SPECTRUM MODEL IN MatLab OUTPUT VOLTAGE

AND CURRENT SINGLE PHASE THYRISTOR FUELLED BY RL-LOAD

 

І.M. Golodnyi, O.V Sanchenko

 

Analysis of recent researches and publications. For low-power asynchronous motors with  a square-cage rotor, it is relatively easy to regulate the speed by changing the voltage on the stator since they have soft mechanical characteristic on the working part. The most simple and cheap for a given type of regulation are the amplitude regulators of the voltage supply [1, 2].

The purpose of the research is reducing time and costs for research of electromagnetic processes of thyristor voltage regulator with the help of computer simulation.

The materials and methods of research. Analysis of the spectral composition of the output voltage of semiconductor converters for the selected control method was carried out using the provisions of the theory of electrical circuits with sinusoidal and non-sinusoidal periodic current and computer simulations in MatLab system [3].

The results of the research. For analysing the characteristics of single-phase thyristor voltage regulator with phase-pulse control of a computer model in MatLab was developed. Power circuit of the  converter consists of a source of alternating current, two thyristors connected in anti-parallel and active-inductive load. Control circuit for the thyristors allows synchronous sinusoidal voltage to open the thyristors from a different angle a.

When applying a control signal to the Thyristor of positive half-wave to open it, the current due to the presence of inductance in the load, increases not abruptly, but smoothly. Moreover, when the voltage of the phase feeding the thyristor passes through zero, the current does not disappear, but under the influence of the EMF of self-inductance  which is generated by the inductance load LНАВ it continues to flow for some time, overcoming the negative voltage phase. The thyristor is closed with a certain delay, when the current through it reaches zero. The amount of reverse phase voltage depends upon the magnitude of inductance in the load.

One of the important features of a thyristor voltage regulator is its ability to regulate the output voltage when changing the angle a, which is non-linear. In the section a from 00 to g (g - torque-turn angle  of closing the thyristor) output voltage corresponds to the mains voltage, when a = 90+g is output voltage two times smaller  than supply voltage. When a= 1800 output voltage is zero.

Harmonic composition of output voltage and current contains all unpaired harmonics. When reducing the output voltage, particularly below 100 V, 3 harmonic approaches the fundamental one, which distorts the mode of the voltage and current load.

Conclusions

The researches have established that the thyristor is closed with a certain delay, when the current through it reaches zero. The amount of reverse phase voltage depends upon the magnitude of inductance in the load.

Control characteristic has a nonlinear dependence, with a decrease of the opening angle a до 400 the output voltage of the thyristor regulator is almost unchanged, after 400 voltage decreases sharply.

 Spectrum of output voltage and current contains all unpaired harmonics.

Harmonic coefficient of  output voltage and current increases abruptly with lowering the output voltage less than 100 V.

The results of investigations can be used in the development of single-phase thyristor voltage regulator for the controlled asynchronous electric drive.

 


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Посилання


Golodnyi, I. M. ed. (2015) Adjustable Electric [Rehulovanyi elektropryvod]. "ZP "Komprynt ", 509.

Glazenki, T. A., Khrisanov, V. I (1983) The semiconductor system of low power asynchronous electric pulse [Napivprovidnykovi systemy impulsnoho asynkhronnoho elektropryvodv maloiu potuzhnosti]. Energoatomisdat, Leningrad. dep-tion., 170.

German-Galkin, S. G. (2002) Power Electronics: Laboratory work on the PC: [Sylova elektronika: laboratorni roboty na PK].Petersburg: CROWN print,304.


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