Design and Multiobjective Optimization of Dual-Circulation Cooling System Considering Electro-Thermal Coupling for IPMSM

Benefiting from high power density, high reliability, and wide speed range, interior permanent magnet synchronous motors (IPMSMs) have received unprecedented attention. However, due to torque ripple and heat dissipation difficulties caused by the compact structure, the development of IPMSM is not smooth in high-end applications such as electric vehicles. In this article, a dual-circulation cooling system consisting of an external housing water-cooling cycle and an internal rotor-stator air-cooling cycle based on improved magnetic circuit design is innovatively proposed. While the electromagnetic characteristics are substantially improved, the temperature rise problem is also significantly suppressed and weakened. Furthermore, to further optimize multiphysics performance for the IPMSM equipped with this system, an improved multiobjective optimization model considering electro-thermal coupling is studied. Optimization effect is greatly improved by the flexible application of segmented orthogonal experiments, correlation/interaction analysis, and intelligent surrogate model/advanced algorithm. Computational fluid dynamics (CFD) and finite element analysis (FEA) highlight the advantages of proposed dual-circulation cooling system and improved optimization model. Their design rationality, effectiveness, and engineering practicability have been well verified through a series of comparative analyses.