Design of PMSM by using fast and accurate stepwise coupled analysis

Abstract

This paper proposes the fast and accurate stepwise coupled electromagnetic-thermal analysis to permanent magnet synchronous motor (PMSM) considering any operating pattern of electric brake. Electric characteristics such as efficiency and losses are changed monotonically according to temperature. In this reason, a mathematical modeling which is fitted with a second order polynomial equation is conducted. In that fitting, the number of analysis point to describe accurate electric parameters including d, q axis inductance and flux linkage by permanent magnets (PMs) is selected. The mathematical models of electric characteristics are coupled to the lumped-parameter thermal network (LPTN) to calculate temperature distribution of PMSM. In the LPTN, the heat source which is losses such as copper and core loss of PMSM are calculated by using the mathematical models. Both electric characteristics and temperature distribution according to the operating pattern are calculated simultaneously by using the proposed coupled analysis method. After the coupled analysis, the improved design considering real-time temperature is conducted to alleviate the maximum temperature. The experimental verification for the improved designed model will be conducted in the final paper.