Controle sem sensores mecânicos para gerador síncrono a ímã permanente

Abstract

This Thesis proposes sensorless vector control schemes that combine designed observers in the discrete-time domain to estimate the rotor position and speed for a permanent magnet synchronous generator of non-salient poles. Two control schemes are proposed. The first scheme is based on a discrete sliding mode current observer in series with an adaptive electromotive force observer. Then, the sliding conditions that assure the sliding motion around the sliding surface are derived to ensure the stability of the current observer as well as an innovative design procedure is proposed for it. Moreover, the electromotive force observer is designed using Lyapunov s Discrete Direct Method, which provides the estimated rotor position and speed. The second scheme extends the developed methodology for the former, considering the parametric uncertainties and eliminating the high frequency components of chattering. The second scheme uses a discrete sliding mode current observer as in the first scheme. However, the electromotive force observer is replaced by a phase-locked loop in series with a discrete sliding mode robust differentiator, which follows the proposed methodology for the discrete sliding mode current observer. Experimental results validate the theoretical analysis and demonstrate the performance of the proposed control schemes considering a small scale wind energy conversion system. In addition, proposed schemes are compared with others of the literature. It should be noticed that the whole approach is carried out in discrete time domain making it suitable for a microcontroller or digital signal processor implementation.