Design optimization of air-ducts in rotating machines with high power density

Recently, the request for the compactness of rotating machines such as traction motors has been increasing and thus the rotating machines should be of high power density. The compactness of motors makes the problem of the magnetic saturation more serious. With this background, this paper describes the design optimization of air-ducts in induction motors. By investigating the relationship between the rotor-yoke configuration with air-ducts and the magnetic flux density in the air-gap, we determine the desirable air-ducts arrangement. Some numerical results, which demonstrate the validity of the proposed approach, are also presented