Transient thermal model of a permanent magnet synchronous planar motor considering spreading thermal resistance

The permanent magnet synchronous planar (PMSP) motor is special planar positioning equipment that has received increasing attention in the academic and industrial fields because of its high positioning accuracy. However, PMSP motors require higher current density to achieve large thrust compared with conventional rotating electrical motors. Such a requirement results in great loss and rapid temperature rise. In this study, a thermal resistance network model is proposed to investigate the transient temperature field of PMSP motors. The spreading thermal resistance among coils, iron cores, and the supporter is obtained based on the equivalent thermal circuit method and solved by the variable separation method, which can generate the transient temperature field for the PMSP motors modeling. The transient temperature field is obtained by solving the model through Laplace and inverse-Laplace transformation. Results are in good agreement with finite element simulations and thus show that our model is valid. The effect of thermal resistance and thermal capacitance on the maximum temperature rise is also investigated based on the proposed model. High thermal capacitance and low thermal resistance are found to improve heat transfer performance. The analytical model can be useful in the thermal design of PMSP motors.