Two-Step Continuous-Control Set Model Predictive Current Control Strategy for SPMSM Sensorless Drives

Integration of model predictive current control (MPCC) and the existing position estimation method is an attractive and promising strategy for surface-mounted permanent magnet synchronous machines (SPMSMs) sensorless drives. However, its system control performance is severely weakened by the filter delay and position estimation errors in the position estimation process because the conventional MPCC requires accurate rotor position information. In order to effectively resolve these problems, a two-step continuous-control-set MPCC (TS-CCS-MPCC) strategy is proposed in this paper. By adopting the two-step prediction to complete the machine mathematical model, the predictive currents can be obtained without the estimated rotor position. Meanwhile, a new proportional cost function is developed to obtain the optimal voltage vector. With the proposed control strategy, the necessary position estimation process in the conventional MPCC can be removed, and the MPCC-based sensorless control can be achieved rapidly and steadily, which not only simplifies the whole implementation process but also dramatically improves the system dynamic performance. Besides, the one-beat delay compensation and machine parameter identification are deduced to enhance the control performance of the proposed scheme. Finally, the experiments validate that the proposed sensorless control scheme can achieve excellent control performance for both steady-state and dynamic operations.