Predictive Control Of Open-Winding Permanent Magnet Synchronous Motor Model And Its Zero-Sequence Current Suppression Strategy

The open winding permanent magnet synchronous motor with common DC bus topology has advantages such as flexible control,high voltage utilization efficiency,and multi-level operation characteristics.Compared with the traditional permanent magnet synchronous motor driven by a single inverter,the open winding motor is powered by dual inverters,and the topology with a common DC bus structure has the advantage of simple structure and improved motor efficiency with only a single power source.It has attracted the attention of many scholars in the field of new motor research at home and abroad.However,the zero-sequence current caused by the existence of a zero-sequence circuit in the common DC bus topology leads to a decrease in the motor’s operating performance.Therefore,the problem of zero-sequence current suppression in open winding permanent magnet synchronous motors has become a hot research topic in recent years.This thesis focuses on the model predictive control technology of open winding permanent magnet synchronous motors and the problem of zero-sequence current suppression in the common DC bus topology.Firstly,an improved single-vector model predictive control strategy with a parallel structure is designed.By optimizing the candidate voltage vector quantity and using the cost function of the parallel structure,the need for designing weight factors in traditional model predictive control is effectively avoided,and the effect of zero-sequence current suppression is improved.Then,in order to solve the problem of limited effect of single-vector control technology,a cascaded three-vector model predictive control strategy is proposed.By the optimized method of two-step cascaded control of dead-beat predictive control and model predictive current control,the accurate tracking of dq-axis current and zero-sequence current is achieved.At the same time,considering the conflict between vector action time and control period,the voltage vector action rule is optimized.The cascaded structure eliminates the weight coefficient design process,effectively reduces the complexity of model predictive control,and reduces the controller calculation burden.Compared with the traditional model predictive control scheme,the two improved model predictive control strategies proposed in this thesis do not need to design weight factors,effectively reducing the complexity of model predictive control,and have good zero-sequence current suppression effect.The steady-state and dynamic operating performance of the motor have been improved.Finally,based on the dSPACE real-time simulation system,an experimental platform for open winding permanent magnet synchronous motors is designed and constructed,and the two improved control strategies proposed in this paper are experimentally verified.The experimental results show that the proposed control strategies can effectively suppress zero-sequence current and significantly reduce the complexity of the model predictive control algorithm.