Discrete-time control of high-speed salient machines

In modern electrical drives, all regulators are implemented in discrete-time domain. The design of the current controller in the continuous time and its following discretization is a common and effective procedure as long as the ratio between the fundamental frequency and the sampling frequency remains sufficiently small. If this condition is violated, the performance of the closed-loop system becomes increasingly poor or even unstable. Literature has proposed some effective strategies to design the controllers directly in the discrete-time domain, but these methods can be applied only to nonsalient machines. However, saliency is another major cause of loss of performance when not properly considered. This paper focuses on the extension of the discrete-time design rules to salient machines. Simulation and experimental results demonstrate the effectiveness of the proposed approach.