UDC 621.3

O. Kyrychenko¹, Candidate of Technical Sciences, Associate Professor
I. Sidorika², Candidate of Technical Sciences, Associate Professor
D. Marchenko¹, Candidate of Technical Sciences
¹Mykolayiv National Agrarian University
²National Shipbuilding University named after. Admiral Makarov

Introduction. According to the state educational standards of Ukraine, the passage of laboratory practice in the discipline of electrical engineering and electronics basics involves the practical development of students’ experimental methods for studying electric circuits and consolidation of theoretical knowledge and skills, as well as familiarity with electrical measurements.
The error in determining of parameters and electric circuits operating modes by calculation and obtained experimentally differs in magnitude, which in some cases amounts to 10-15%. One of the reasons that affects the error magnitude is the heat emission in the electric circuit’s elements, which leads to an increase in the spread of their parameters, which was not taken into account before.
Research methodology. The methodology for studying the elements of the training and testing stand of the electrotechnical laboratory envisaged the creation of a geometric, finite-elemental and realistic 3D-resistor models.
Electrothermal analysis of the electrical laboratory training bench elements was carried out using numerical simulation.
Research results. The distribution of the main electric and thermal quantities by the volume of the electrical laboratory’seducational-research stand element is established.
As a result of the electrothermal analysis, different values of the resistor heating were obtained at a different magnitude of the current strength flowing through it, on the basis of which the resistor’s electrothermal characteristics were constructed. The resulting thermal model is adiabatic, and therefore the resulting numerical values for temperature should be considered as the upper thermal limit.
Conclusions. Conducting an electrothermal analysis of elements of the UNSS-1 training laboratory unit allowed to establish the distribution of the main electrical and thermal variables by the volume of the training laboratory stand element.
The influence of heat on the accuracy of calculations in determining the parameters and modes of operation of electric circuits by calculation and determined experimentally is determined. Taking into consideration thermal flux has increased the general accuracy of electric parameters calculations, since the error was not more than 5-7%.

Keyword: electrothermal analysis, educational and research stand, electrotechnical laboratory, modeling, temperature fi eld.

Electrothermal analysis of elements of the educational and research laboratory stand of the electrotechnical laboratory.

Issue 4 (96), 2017

UDC 621.3

O. Kyrychenko, Candidate of Technical Science, Associate Professor
Mykolayiv National Agrarian University

The numerical simulation of main characteristics of magnetic field for metal conductive buses of rectangular cross section is performed. The electromagnetic field pattern and quantitative parameters for magnetic induction, magnetic field strength and volumetric energy density are obtained. The graphic illustrations demonstrate visually the uneven distribution of the electromagnetic field on the geometry of the conductive bus. The usability of numerical analysis of the characteristics of electromagnetic field for metal conductive buses is shown.

Key words: electromagnetic field, magnetic induction, magnetic strength, metal buses, rectangular section.

Simulation of electromagnetic field characteristics for metal conductive buses with rectangular cross-section.

Issue №1 (93), 2017

UDC 681.5

D. Shareiko,
I. Bilyuk,
A. Fomenko,
O. Savchenko,
A. Kirichenko 

The work considers the peculiarities of the way the follow-up system based on the piezoelectric engine functions. The system consists of a piezoelectric engine of the reverse rotation, presented as two independent piezoelectric engines of rectified rotation with the common arbor and separate power supply units; a feedback sensor, a comparator unit, a reverse control unit; a step-length control unit and a clock frequency generator.
It has been defined that unlike the control system with single value nonlinearity, for which Popov criterion is applied to research the stability of the equilibrium, the stability of the control system of the piezoelectric engine with hysteresis nonlinearity and numerous equilibrium positions is evaluated applying the stability criterion of Yakubovitch. To analyze the stability of the control units of the piezoelectric engine with hysteresis nonlinearity, a generalization is used, under which control unit system links are transformed into a hysteresis link of the nonlinear part and links of the linear part of the control unit.
The functional chart of the control unit of the deformation of the piezoelectric transducer is analyzed. The research has been done on the absolute stability of the control unit of the deformation of the piezoelectric transducer for nano- and micro displacements under deterministic impacts based on criterion of Yakubovitch.
Amplitude-phase-frequency characteristics have been built on the complex plane for two kinds of curved lines, for which the conditions of stability are met but the conditions of absolute stability of the control unit of the deformation of the piezoelectric transducer are not met. It is defined that the frequency criterion of the absolute stability is simple and convenient for the synthesis of the compensating devices of the control unit of the deformation of the piezoelectric transducer for nano- and micro displacements. It has been noted that the frequency criterion of the absolute stability of numerous equilibrium positions in a nonlinear system with one hysteresis nonlinearity of the piezoelectric transducer is true both for the systems with deterministic and random processes, as well as both for lumped parameters and distributed constants.
Analytic formulae have been obtained for the synthesis of the follow-up control system based on the piezoelectric engine with the ability to change from step running to continuous operation and back.

Key words: follow-up system; automatic control unit; piezoelectric engine; absolute stability; stability criterion of Yakubovitch; compensating device.

Synthesis of the follow-up system based on the piezoelectric engine.

References:
1. Smyrnov A. B. Mekhatronyka y robototekhnyka. Systemы mykroperemeshchenyi s pezoэlektrycheskymy pryvodamy [Tekst] / A.B. Smyrnov – S.-P.: SPbHPU, 2003. – 160 s.
2. Afonyn S. M. Yssledovanye absoliutnoi ustoichyvosty systemы upravlenyia deformatsyei pezopreobrazovatelia dlia nano- y mykropreobrazovatelei [Tekst] / S. M. Afonyn // Mekhatronyka, avtomatyzatsyia, upravlenye. – 2008. – N 1. – S. 10-16.
3. Shareiko D.Yu. Slidkuvalna systema na osnovi piezoelektrychnoho dvyhuna [Tekst] /D.Yu.Shareiko, I.S. Biliuk, A.M. Fomenko, O.V. Savchenko // Suchasni problemy avtomatyky ta elektrotekhniky / Materialy Vseukrainskoi naukovo-tekhnichna konferentsii. m. Mykolaiv, 21-22 kvitnia 2016 roku – S. 24 – 25
4. Popovych M.H. Teoriia avtomatychnoho keruvannia / M.H. Popovych, O.V. Kovalchuk – K. : Lybid, 2007. — 656 s.

Issue 4 (92), 2016