Design Process of a Hybrid Excited Synchronous Machine with Stator Cage Winding

The analytical design of well-known machine types is discussed in several literature. Since the hybrid excited synchronous machine with stator cage winding is the subject of this paper, different peculiarities have to be taken into account analytically. For the stator design it is mandatory to estimate the number of stator bars. An appropriate equation is formulated based on the torque calculation of the machine. Moreover different conditions regarding the torque ripple and suitable numbers of stator bars can be defined. The rotor excitation needs to be distributed due to the hybrid excitation. Also a constraint for the maximum current linkage is necessary, because of the restriction of no active rotor cooling. This is done by developing a separate algorithm. A subsequent optimisation completes the design process. Finally, the design and conditions for low torque ripple are confirmed using finite element analysis.