# A METHOD FOR CALCULATING MECHANICAL CHARACTERISTICS OF INDUCTION MOTORS WITH SQUIRREL-CAGE ROTOR

## Authors

• V. S. Malyar Lviv Polytechnic National University, Ukraine
• A. V. Malyar Lviv Polytechnic National University, Ukraine
• A. S. Andreishyn Lviv Polytechnic National University, Ukraine

## Keywords:

induction motor, squirrel-cage rotor, static characteristics, saturation, displacement of the current

## Abstract

Purpose. Development of a method for calculating mechanical characteristics of induction motors, taking into consideration saturation of the magnetic path and displacement of the current in the rotor bars. Methodology. The algorithm is based on calculating the steady-state mode of induction motor operation for a set slip, described by a system of non-linear algebraic equations of electrical equilibrium, whereas the mechanical characteristic is evaluated as a set of steady-state modes using parameter continuation method. The idea of the steady-state mode calculation consists in determining vectors of currents and flux linkages of the motor circuits, using which makes it possible to evaluate the electromagnetic torque, active and reactive powers, etc. Results. The study resulted in the development of a method and algorithm for calculating static characteristics of induction motors, which allows looking into the effect of different laws of voltage regulation on the mechanical characteristics, depending on the frequency change. Originality. An algorithm for calculating mechanical characteristics of the squirrel-cage induction motor was developed based on the mathematical model of the induction motor in which electromagnetic parameters are calculated using real saturation curves for the main magnetic flux and leakage fluxes, and displacement of the current in the rotor bars is evaluated by presenting the rotor winding as a multi-layer structure. Applying the transformation of the electrical equilibrium equations into the orthogonal axes enabled a significant reduction of calculation volume without impairing the accuracy of the results. Practical value. The developed algorithm allows studying the effect of different laws of scalar regulation of the voltage on the mechanical characteristics of the induction motor in order to obtain the necessary torque-speed curves for their optimization. It can be used for programming frequency converters.

## References

Pivnyak G.G., Volkov A.V. Sovremennye chastotno-reguliruemye asinkhronnye elektroprivody s shirotno-impul'snoi moduliatsiei [Modern frequency controlled asynchronous electric drives with pulse width modulation].Dnepropetrovsk, NGU Publ., 2006. 470 p. (Rus).

Novotny D.W., Lipo T.A. Vector Control and Dynamics of AC Drives. Clarendon PressOxford, 2003. 440 p.

Pabitra Kumar Behera, Manoj Kumar Behera, Amit Kumar Sahoo. Speed Control of Induction Motor using Scalar Control Technique. International Journal of Computer Applications. Proceedings on International Conference on Emergent Trends in Computing and Communication ETCC, 2014, no.1, pp. 37-39.

Aspalli M.S., Asha R., Hunagund P.V. Three phase induction motor drive using IGBTs and constant V/F method. International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering, 2012, vol.1, iss.5, pp. 463-469.

Finch J.W., Giaouris D. Controlled AC Electrical Drives. IEEE Transactions on Industrial Electronics, 2008, vol.55, no.2, pp. 481-491. doi: 10.1109/TIE.2007.911209.

Boldea I. Control issues in adjustable speed drives. IEEE Industrial Electronics Magazine, 2008, vol.2, no.3, pp. 32-50. doi: 10.1109/MIE.2008.928605.

Vaskovskyi Yu.N., Gaydenko Yu.A., Tsivinskiy S.S. Integral characterization of electrical machines with electromagnetic field theory methods. Electrical Engineering & Electromechanics, 2006, no.1, pp.28-32. doi: 10.2098/2074–272X.2016.01.05.

Milykh V.I., Polyakova N.V. Determination of electromagnetic parameters of electric machines based on numerical calculations of magnetic field. Electrical Engineering & Electromechanics, 2006, no.2, pp.40-46. doi: 10.2098/2074–272X.2016.02.09.

RogersG.J., Benaragama D.S. An induction motor model with deep-bar effect and leakage inductance saturation. Archiv für Elektrotechnik, 1978, vol.60, no.4, pp. 193-201. doi: 10.1007/bf01595160.

Stakhiv P., Malyar A. Influence of saturation and skin effect on current harmonic spectrum of asynchronous motor powered by thyristor voltage regulator. Proceedings of the IVth International Workshop Computational Problems of Electrical Engineering. Gdynia, Poland, June 1-3, 2005. pp. 58-60.

2019-04-15

## How to Cite

Malyar, V. S., Malyar, A. V., & Andreishyn, A. S. (2019). A METHOD FOR CALCULATING MECHANICAL CHARACTERISTICS OF INDUCTION MOTORS WITH SQUIRREL-CAGE ROTOR. Electrical Engineering & Electromechanics, (2), 9–13. https://doi.org/10.20998/2074-272X.2019.2.02

## Section

Electrical Machines and Apparatus