Thermal Investigation For Permanent Magnet Synchronous Motor Based On Lumped-parameter Thermal-network

Permanent Magnet Synchronous Motor has taken the lead in modern electric propulsion system, for its superior performances, such as simply structure, high efficiency, and excellent reliability. However, under special working condition, motor is supported by frequency control system, which results in complex loss distribution.Especially eddy loss and harmonic loss are multiplied, causing serious temperature rise. In this case, the permanent magnet could easily loss of excitation, which may affect the whole system's durability and even cause accidents. Besides that,According to existing references, FEM and FVM are broadly used to analysis temperature field of motor; but there are not many literatures explored the change of temperature rise of PMSM in both steady state and transient state using Lumped-parameter Thermal-network(LPTN) method. Furthermore, the computational accuracy should be improved either.Therefore, in order to investigate the characteristics of thermal distribution, a 50 kW Surface Permanent Magnet Synchronous Motor(SPMSM), used in warships,was researched in this paper. Based on the LPTN method and numerical heat transfer theory, a LPTN model of the whole solution domain in the SPMSM is established,considering its special structural and cooling features. As the same time, a 3D fluid model of the cooling medium was simulated by finite volume method, to analysis heat transfer coefficients on the fluid-solid interfaces. Beyond that, the temperature of the SPMSM, operating under frequency conversion system, is calculated efficiently and effectively, and draws a good deal of conclusions. What is more, to clarify accurate thermal distribution of different components, more nodes are adopted in the model, and the temperature rise in both steady and transient states are simulated respectively. At last, this paper puts forward an indirect testing means, byusing this way the correctness of calculated results and the accuracy of the solution method were verified by experimental data.