A comparative study of high-speed permanent magnet synchronous motor for air compressor

A high-speed and high-power density electrical motor is needed for air compressor which supplies highly pressured air to fuel cell system. With the aid of high energy magnet materials and adjustable speed drives, the applications of high-efficiency and high-performance permanent magnet synchronous motors (PMSM) have been extensively increased. As a result, PMSM is the best suited candidate for this kind application from the viewpoint of efficiency, cost, compactness, ruggedness and thermal reliability. In this paper, two types rotor structure are considered. One is solid circular shape permanent magnet rotor and the other is circular ring shape. And retaining sleeves which made of stainless steel are installed on both rotors to protect permanent magnet from excessive centrifugal force. The mechanical and electromagnetic considerations were done to determine optimum retaining sleeve thickness. Finally, characteristic comparisons between two types of rotor are made.