MAGNETIC COENERGY BASED MODELLING OF PMSM FOR HEV/EV APPLICATION

Permanent-magnet synchronous motors (PMSM) used for HEV/EV drive train have many nonlinear characteristics including saturation, slotting effects and non-sinusoidal back-emf. However, accurate torque control and rigorous on-board-diagnose require precise modelling that goes far beyond capacity of conventional Space Vector based PMSM model considering only fundamental frequency. By considering the higher harmonics of PMSM, this paper introduces a novel PMSM model named Generalized Space Vector Model (GSVM) based on Fourier series reconstruction of magnetic coenergy. Firstly, two-dimensional Fourier series supplemented by polynomial fitting is introduced to reconstruct the numerical solution of coenergy from Finite Element Analysis (FEA). Secondly, analytical models of flux linkage, electric torque and voltage equation in stator current oriented synchronous frame are derived based on the reconstructed coenergy model. Finally, the steady and dynamic characteristics of GSVM are validated against experimental results.