Contribuições ao controle do motor síncrono de ímã permanente com FCEM não senoidal

Abstract

This thesis presents contributions to the sensorless vector control of Permanent Magnet Synchronous Motors (PMSM) with nonsinusoidal back Electromotive Force (back- EMF), whose magnets are allocated on the rotor surface. The proposed technique can reduce the oscillations in the electromagnetic torque and the copper losses in the stator windings depending on the back-EMF. In order to understand the motivation of this work, the particularities that differentiate PMSMs are initially discussed. Thus, this motor can be contextualized in the development of more efficient products. In the following, two dynamic models of nonsinusoidal PMSM are derived. The first model represented in stationary reference frame is used to determine a stator current observer. This observer is expressed in discrete time and is based on high order sliding mode, specifically, in the super-twisting algorithm with a new modification, that uses variable gains for chattering minimization. The second model that is derived from a new synchronous transformation frame oriented on back-EMF vector, is used to vector control of PMSM. In addition, a selective filtering process is included in the control system, allowing to eliminate the residual chattering of the estimates of back-EMF and to implement the proposed transformation in a hybrid vector control system, which provides the sinusoidal and non-sinusoidal vector control. As result, it is possible to achieve improvements in the motor energy efficiency. In order to allow the operation at low speeds and at standstill, I-f control method is adopted with some enhancements. Among these enhancements, it can be highlighted the methodology for motor starting design and the bidirectional transition method that allows a smooth and fast transition between the control strategies. Finally, simulation and experimental results are presented to validate the theoretical developments and to demonstrate the feasibility of implementation.