A robust current control based on proportional-integral observers for permanent magnet synchronous machines

摘要

This paper deals with a novel robust current control scheme for Permanent Magnet Synchronous Machine based on the conventional cascade structure. The main idea is to substitute the commonly used decoupling network, which requires the precise knowledge of the system parameters in any working condition, with a more flexible and robust scheme. In particular, the traditional configuration is improved by mean of two proportional-integral observers which allow the preservation of the drive performances under the effects of disturbance. The improved robustness is achieved maintaining the reliable basic scheme with a pure proportional controller in the forward path with advantages in terms of design and tuning. A genetic algorithm is used to optimize the controller and the observer parameters. This multi-objective optimization leads to a good stability and an overall improved performance of the drive above all the operative range. The choice of the optimal solution is based on a novel fitness function which takes into account both dynamical features and disturbance rejection capabilities of the system. The effectiveness of the proposed control scheme is verified by mean of numerical simulations and experiments as well.