Analytical Model for No-Load Magnetic Field, Can Losses, and Temperature of Permanent Magnet Canned Motor

The stator and rotor can are added to the permanent magnet canned motor (PMCM) to prevent the stator and rotor core corrosion. The can losses accounts for about 40% of the total losses, therewith the temperature problems can be brought in this kind of motors. Based on this, the accurate analytical calculation method of the magnetic field, can losses, and temperature of PMCM is the key to the rapid design of this kind of motor. The no-load magnetic field is solved by the subdomain method, and the harmonic magnetic density is decomposed by Fourier. Secondly, the calculation formula of can losses is proposed based on the law of electromagnetic induction. The derived calculation formula of can losses can separate the can losses into each harmonic can loss. Then, the results of the analytical solution are added into a new thermal network model (TNM) to predict the temperature distribution of the cans accurately. The new TNM of PMCM can consider the influence of uneven heat dissipation of cans and cooling channels. The key is to re-divide the structure of cans and winding and improves its thermal resistance calculation formula. Finally, the effectiveness of the proposed TNM is verified by comparing it with the results of experiment.