Research on <i>dq</i> -axis current distribution and control strategy of a novel negative-salient PMSM for vehicle

Purpose As the new energy vehicle industry advances, the demands for motors’ speed regulation range and power density are steadily rising. This paper aims to design a motor that combines high efficiency with a wide high-speed range and high power density. To achieve this, a negative-salient permanent magnet synchronous motor is proposed (NSPMSM). Design/methodology/approach This paper presents a new NSPMSM topology for vehicles, which is based on the conventional interior permanent magnet synchronous motor. Firstly, the current trajectories in various operating regions of the NSPMSM are analyzed, along with the effect of the saliency ratio for the distribution of dq-axis current. Secondly, the field-circuit co-simulation framework is built based on the finite element method, using Maxwell-Simplorer-Simulink Real-time data exchange between different software tools allows for transient simulation of the model under varying operating conditions. Through simulations, the laws of distribution of dq-axis current, current variations under changing conditions, and transient data of the NSPMSM are verified. Additionally, the speed range of constant power and full-speed domain efficiency of the NSPMSM are analyzed. Findings The results indicate that compared to conventional motors, the NSPMSM increases the speed range from 4.5:1 to 6.5:1, effectively broadening speed range of the motor, while also improving efficiency under high-speed operating conditions. Originality/value The proposed NSPMSM can effectively increase power density and expand the motor’s speed regulation range.