Small signal stability of three-phase and six-phase synchronous motors: A comparative analysis

Small signal stability analysis is conducted for an asymmetrical six-phase synchronous motor in comparison with its equivalent three-phase counterpart. For this purpose, a linearized model of the six-phase synchronous motor is developed using the dq0 approach, which is used in eigenvalue criteria to determine absolute stability in comparison with its equivalent three-phase counterpart. The analysis includes a comparison of the variation in evaluated eigenvalues associated with the stator and rotor sides according to changes in both the three and six-phase machine parameters and working conditions. Key analytical results are experimentally investigated and validated on a test rig.