Parameter Determination of PMSM using Coupled Electromagnetic and Thermal Model Incorporating Current Harmonics

Motivation: Permanent magnet synchronous machines (PMSMs) are widely used for electric vehicle (EV) propulsion owing to its high performance capabilities over a wide operating range [1]. With advent in machine structure and inverter topologies, accurate parameter determination incorporating machine non-linearities and effects of time and space harmonics is of paramount significance for high-performance control and analysis. Although classical $dq -$axis modeling is widely incorporated: 1) it fails to incorporate the machine non-linearities such as magnetic saturation, cross-saturation and leakage effects; 2) the spatial harmonic contents caused by machine winding and structural configuration are not considered in inductances and flux linkage; and 3) the effects of operating temperature on parameter variation are neglected [2]; and 4) it requires information from experimental data or complex look-up tables for parameter determination. On the other hand, finite element analysis (FEA) is computationally extensive and modelling of time harmonics becomes complex. Thus, in this paper, a coupled electromagnetic and thermal model incorporating current harmonics for parameter determination is developed and validated for a fractional-slot distributed wound (FSDW) laboratory PMSM.