Horoshko V. Optimization of dynamic modes of electric machines using fractional-order integral controllers.

Objects of research in the dissertation – electromechanical systems, a characteristic feature of which is the presence of a significant power dependence in the mathematical description. Because of this, there are problems in choosing the structure and parameters of the controllers. In particular, in a DC motor with sequential excitation, a switched reluctance motor and electromagnetic retarders, the magnetic system can be saturated in static and dynamic modes. The fractional-integral calculus used in the work allows to describe such nonlinear objects with high accuracy by linear transfer functions of fractional order. Thus, for the armature circuit of a DC motor with sequential excitation, such an approximation gives the least root mean square error. The combination of a conventional PID controller with fractional-integral components of the order of 0.35 and 1.35 provides the best quality of the transient process – the current reaches the reference value as quickly as possible without overshoot. Secondly, the switched reluctance motor, in the model of which it is necessary to take into account power dependences, is described by the aperiodic function of the order of 0.7 when describing the transient processes of the speed during a voltage jump. From the family of studied controllers, the traditional PI-controller with additional fractional-integral components of the order of 0.7 and 1.7 provided the astaticism of the speed loop of the order 1.7 and the smallest overshoot. The third object studied – electromagnetic retarders mounted on the drive wheels of the car to tune the internal combustion engine – also is most accurately described by the transfer function of the fractional order. With the help of the PIDIγIμ-controller, which provided the closed-loop astaticism of the order of 1.63, the stabilization of the speed of rotation of the two wheels without antiphase oscillations and the exact trajectory of the triangular tachogram were achieved. Thus, thanks to the apparatus of fractional-integral calculus, more accurate identification of object parameters is provided, the mathematical description is reduced to linear transfer functions of fractional order, in closed systems it is possible to provide astaticism of fractional order 1.3 ... 1.7 to achieve better quality of transients than using classical methods.