Model-Free Speed Control with Modified State Observer for Finite-Set Predictive Current Control of PMSM Drives

This paper presents an improved model-free control (MFC) with a modified state observer to regulate the speed in the finite-set predictive current control (FS-PCC) of permanent magnet synchronous motor (PMSM) drives. In the proposed method, the lumped disturbance is removed from the formulations. So, the extended state observer is not required. Instead, a function of the estimation error plays the role of the lumped disturbance. In this way, a simple yet precise disturbance estimation is achieved. Furthermore, the proposed MFC utilizes a nonlinear control law instead of the regular proportional controller to track the speed reference rapidly. The inner control loop of the drive is constructed based on the model-free FS-PCC. Thus, the overall control system is independent of the classical model of the PMSM creating a fully robust predictive control. The proposed model-free speed-controlled FS-PCC (MFSC-FS-PCC) is evaluated through simulations and experiments. The results show that the proposed method has a fast dynamic response while preserving good steady-state performance.