A Narrow Bridge Structure for Reduction of the Flux Leakage

抄録

Interior permanent magnet synchronous motors (IPMSMs) are widely used because their size can be reduced and their motor efficiency can be improved by utilizing the residual flux of permanent magnets. The reduction of flux leakage from the bridge parts of a rotor is one of the important issues to enhance merit. In this paper, two structures to reduce flux leakage were proposed: 1) lightening of the rotor cores by using a multi-holes structure and 2) applying non-magnetic materials for reinforcing the mechanical strength of the bridge parts. Measurement of a prototype applying the above structures was also performed in a no-load and load condition. The no-load test showed a 3.1% increase in no-load back EMF, and the load test clarified that the motor loss at 8.1Nm and 1000min^-1 was decreased by 1% as an effect of bridge narrowing compared with a conventional motor.