Design study on hybrid excitation flux switching motor with permanent magnet placed at middle of field coil slot for HEV drives

Abstract

This paper presents design study on a hybrid excitation flux switching motor that can compete with an interior permanent magnet synchronous motor installed on TOYOTA PRIUS-2010. A stator body of a hybrid excitation flux switching motor generally consists of not only laminated core and three-phase armature windings, but also field excitation coils and permanent magnets as field mmf sources. This machine can be classified into three types according to permanent magnet location. Two of them have the permanent magnet located at either bottom or top of field excitation coil slot. Each of them has own advantages and disadvantages. In order to mitigate their disadvantages, this design study focuses on another type with the permanent magnet located at middle of field excitation coil slot. The design results using finite element magnetic analysis show that the machine achieves the maximum torque and power for the target vehicle drive under given constraints while reducing coercive force of the permanent magnet required to avoid demagnetization. Experimental results using a test motor are demonstrated to validate the design results.