Robust Cascaded Deadbeat Predictive Control for Dual Three-Phase Variable-Flux PMSM Considering Intrinsic Delay in Speed Loop

In this article, a robust cascaded deadbeat predictive speed control method (PSC) is proposed with speed and disturbance observer for the dual three-phase variable-flux permanent-magnet synchronous motor (VF-PMSM) drives. Considering the intrinsic delay in speed loop, an improved predictive speed model has been derived in discrete domain. In turn, a speed observer is proposed for the cascaded PSC to mitigate the issue of this intrinsic delay. In order to improve the system robustness, the torque disturbance observer including the generalized proportional integral observer and the sliding-mode observer has been proposed for parameter variation and load torque perturbation. Furthermore, the stability analysis indicates that the margin of parameter mismatch is determined by the coefficient in the speed observer, which can be expressed as the equivalent gain in discrete domain. The performance comparison between the conventional PSC method and the proposed PSC method has been investigated for parameter robustness. The experimental results are presented to verify the improvements of the proposed PSC method for the dual three-phase VF-PMSM drives under model uncertainty and magnetization manipulation conditions.