In this work, the analysis and design of a speed control system of a variable reluctance motor with six poles and four phases is presented. The nonlinear motor model includes the nonlinearity of the Coulomb friction plus the viscous friction. The structural analysis of the non-linear model is carried out, which is linearized at the operating point established at 2000rpm. Both the non-linear and linear models are compared both in their structure and in their responses through digital simulations, finding that under certain conditions both have similar behaviors. Subsequently, based on the linear model, a classic PI controller is designed and subjected to regulation, tracking and load torque variation tests. The controller design is carried out using the Bode shaping technique, guaranteeing adequate gain and phase margins with a higher bandwidth than the mechanical subsystem mode. The robustness is verified by means of the digital simulation of the control system using the non-linear model, which is also subjected to load variations, finding that the PI controller has excellent performance in both regulation and tracking. Finally, two additional controllers are proposed: the first is a PII controller, the objective of which is to reduce the effect of the non-linearity called dead zone present in the motor at start-up or at low speeds. The second is a PI controller that adds a new technique for reducing the ripple present in the speed and torque responses, characteristics of this type of motor.
Analysis and Design of Active Suspensions by H.INF. Robust Control Theory.
