Simplified Two-Step Model Predictive Control With Fast Voltage Vector Search

The optimization process of the traditional single-step finite control set model predictive control (FCS-MPC) strategy only considers one control cycle, which leads to the high switching frequency of FCS-MPC and the failure to optimize the voltage vector in the extended range. To balance the relationship between switching frequency and steady-state performance, a simplified two-step finite control set model predictive current control strategy is proposed. In this strategy, the voltage vector in the two control cycles does not change, and the corresponding inverter switching action does not switch, so the switching frequency is suppressed. In addition, a new voltage vector sequence distribution space diagram is established in FCS-MPC where the vector does not change in two-step length. On this basis, the reference voltage calculation scheme based on the no-beat principle is extended to two control cycles. Then, according to the amplitude and sector of the reference voltage in two control cycles, a fast voltage vector sequence positioning scheme is designed to reduce the computational burden. Finally, the effectiveness of the proposed scheme applied to a permanent magnet synchronous hub motor (PMSHM) system is verified by experiments.