Research on Heat-Transfer Characteristics of Cooling System With Heat Pipe Technology for Outer Rotor SPMSM

Heat pipe is a heat transfer element with high thermal conductivity, lightweight, and good temperature equalization, which has broad application prospects in driving motors. First, in order to simplify the complex heat transfer process, according to the heat transfer mechanism of heat pipe, the flow and heat transfer process of the working medium are equivalent to a single heat transfer process, which is equivalent to a solid with a high thermal conductivity. A mathematical model of the equivalent thermal conductivity of heat pipe is established to provide a theoretical basis for accurate calculation of thermal conductivity. The effects of shape size, different working temperatures, material properties of working medium, and contact thermal resistance of heat pipe on their equivalent thermal conductivity and thermal resistance are considered to obtain the equivalent thermal conductivity of heat pipe. On this basis, the experimental test platform of equivalent thermal conductivity of heat pipe is set up, and the accuracy of the mathematical model is verified experimentally. Finally, an outer rotor surface-mounted permanent magnet synchronous motor (SPMSM) based on heat pipe cooling technology is designed and manufactured, and the temperature rise distribution under different operating conditions is tested, and the effectiveness of the proposed cooling technology is verified.