Fractional Integral-Differentiating Control in Speed Loop of Switched Reluctance Motor

This paper deals with the feedback speed control of a switched reluctance motor using the fractional-order controller. Due to the polar-pole construction and pulsed power windings, at which saturation of the magnetic system occurs, standard PI or PID controllers based on motor description with differential equations of integer order have led to significant errors and inaccuracies in the dynamic and static modes. The purpose of the work is optimization of dynamic and static modes using fractional integral proportional controllers. The goal was achieved by solving the problem of identifying a switched reluctance motor based on the fractional order differential equations with a power of 0.7, parameters found by genetic algorithms. It allowed taking into account the nonlinear dependences of the magnetic flux and torque so that the object behaved like a linear one. Then it became possible to synthesize controllers with a fractional order of integration and differentiation based on standard methods of the theory of the automatic control. It was shown that the parameters of the model changed with voltage regulation. The behavior of a closed system was compared when tuning the speed loop to the technical optimum and fractional order of astaticism 1 , taking into account such changes in the control object. Significance of the results consisted in the fact that the fractional order controllers using a motor model based on a fractional-order differential equation ensured a high quality system (the minimum of the first matching time, the overshoot was no more than 2%), unattainable with classical PID controllers