**8. References**

	- Sul, S-K. (2011). *Control of Electric Machine Drive Systems,* IEEE Press, Wiley Interscience, ISBN 978-0-470-87655-8, Hoboken, USA

**Chapter 2** 

© 2012 Muşuroi, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

f Jm f Jm f J 1, 2, 3, ... , j fc f1 (1)

jc f c f 1 f f kf (Jm k)f Jm k f , (2)

distribution, and reproduction in any medium, provided the original work is properly cited.

© 2012 Muşuroi, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**The Behavior in Stationary Regime** 

**Frequency Converters** 

Additional information is available at the end of the chapter

Sorin Muşuroi

**1. Introduction** 

http://dx.doi.org/10.5772/38009

**of an Induction Motor Powered by Static** 

Generally, the electric induction motors are designed for supply conditions from energy sources in which the supply voltage is a sinusoidal wave. The parameters and the functional sizes of the electric motors are guaranteed by designers only for it. If the electric motor is powered through an inverter, due to the presence in the input voltage waveform of superior time harmonics, both its parameters and its functional characteristic sizes will be more or less different from those in the case of the sinusoidal supply. The presence of these harmonics will result in the appearance of a deforming regime in the machine, generally with adverse effects in its operation. Under loading and speed conditions similar to those in the case of the sinusoidal supply, it is registered an amplification of the losses of the machine, of the electric power absorbed and thus a reduction in efficiency. There is also a greater heating of the machine and an electromagnetic torque that at a given load is not invariable, but pulsating, in rapport with the average value corresponding to the load. The occurrence of the deforming regime in the machine is inevitable, because any inverter produces voltages or printed currents containing, in addition to the fundamental harmonic, superior time harmonics of odd order. The deforming regime in the electric machine is unfortunately reflected in the supply power grid that powers the inverter. Generalizing, the

output voltage harmonics are grouped into families centered on frequencies:

and the various harmonic frequencies in a family are:

Wach, P. (2011). *Dynamics and Control of Electric Drives,* Springer, ISBN 978-3-642-20221-6, Berlin, Germany
