Cascaded Three-Vector Model Predictive Control of Open Winding Permanent Magnet Synchronous Motor

Abstract

In order to suppress zero-sequence current (ZCS) of open-winding permanent magnet synchronous motor (OW-PMSM) system with a common DC bus, a cascaded three-vector model predictive control (MPC) strategy is proposed. The proposed control strategy adopts a cascade structure. First, determine the sector where the expected reference voltage vector is located based on the deadbeat prediction model. Then, use the voltage error cost function to select two optimal non-zero voltage vectors in the sector for first-level model prediction. Finally, MPC is carried out by using the zero-sequence voltage cost function, and an appropriate zero vector is injected into the control cycle to achieve the purpose of suppressing ZCS. This scheme does not need to traverse all the voltage vectors, which greatly reduces the amount of calculation. The simulation results show that the proposed cascaded three-vector MPC, compared with the traditional MPC, does not need to design weight coefficients, reduces effectively the complexity of the control strategy, and efficiently suppresses zero-sequence current. Both steady-state and dynamic operating performance of PMSM are improved.