Rotor design strategy of interior permanent magnet synchronous motor for fuel cell electric vehicle

This paper proposes a rotor-design strategy of interior permanent magnet synchronous machine (IPMSM) considering various design constraints for a fuel-cell electric vehicle. The conventional process in the rotor design only considers the magnitude of the iron loss or the magnet loss while neglecting the loss distributions in the rotor core. This approach results in a design where losses are accumulated on a localized region in the rotor core, especially in the case of IPMSM with a fractional number of slots per pole. This can cause significant irreversible demagnetization of the permanent magnets since the rotor core usually suffers from poor heat transfer. The proposed strategy targets this problem by focusing on the loss distributions according to driving condition. In addition, it offers a parallel approach where mechanical stress analysis is combined with the rotor design process in order to guarantee mechanical strength by centrifugal force at maximum speed. The validity of proposed method was verified by comparing simulation result using the finite element method with experimental data.