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Simona Coman1, V. Comnac1, Member IEEE, Cr. Boldisor1, D.C. Dumitrache2
1Automation Department, “Transilvania” University of Brasov, 5 M.Viteazu Str.,
500174 Brasov, Romania, phone/fax: +40 0268 418836,
2 Department of Automatic Control, Technical University of Cluj-Napoca,
26-28 Gh. Baritiu Str., 400027 Cluj-Napoca, Romania

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Abstract –

The distributed control systems with communication
networks are used in many industrial applications. These systems
are often referred as “Networked Control Systems” (NCS). The
network’s induced delays are inevitable, however, when data is
transmitted between control devices. Network delays degrade the
NCS performance and destabilize the system. The goal of the
paper is to analyze the network delays influence over the system
stability by using two DC electrical drives applications, one
having a PI controller, the second an FPI (fractional PI)
controller. The behaviors of the presented control systems have
been examined with MATLAB/SIMULINK simulations. From
here it results that the fractional controller increases the phase
margin, hence improving stability.